Probe shapes that measure time-averaged streamwise momentum and cross-stream turbulence intensity

NASA Technical Reports Server (NTRS)

Rossow, Vernon J. (Inventor)

1993-01-01

A method and apparatus for directly measuring the time-averaged streamwise momentum in a turbulent stream use a probe which has total head response which varies as the cosine-squared of the angle of incidence. The probe has a nose with a slight indentation on its front face for providing the desired response. The method of making the probe incorporates unique design features. Another probe may be positioned in a side-by-side relationship to the first probe to provide a direct measurement of the total pressure. The difference between the two pressures yields the sum of the squares of the cross-stream components of the turbulence level.

The association of BMI and WHR on blood pressure levels and prevalence of hypertension in middle-aged and elderly people in rural China.

PubMed

Zhao, W H; Xu, H Q; Zhang, X; Wang, J I; Yin, C C; Li, M; Chen, J S

2000-09-01

The purpose of this study was to examine the effects of BMI (Body Mass Index) and WHR (Waist Hip Ratio) on average blood pressure and the prevalence of hypertension in middle-aged and elderly population in rural China. A total of 12955 subjects including 6276 males and 6688 females over 40 years of age were surveyed. Height, weight, waist circumference, hip circumference and blood pressure were measured. The association of BMI and WHR on average blood pressure levels and prevalence of hypertension were analyzed by dividing BMI and WHR into tertiles. The average blood pressure levels and the prevalence of hypertension in males and females increased significantly with the increase of BMI or WHR (P < 0.01), as well as with the increase of both of them (P < 0.01). The average blood pressure and the prevalence of hypertension stopped increasing when WHR was > or = 0.76, suggesting that WHR > or = 0.80 could be used as a cut-off value for the prediction of hypertension risk for both males and females. Therefore hypertension could be effectively prevented and controlled by controlling BMI and WHR.

Effects of nitroglycerin and nitroprusside on vascular capacitance of anesthetized ganglion-blocked dogs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1991-10-01

To determine whether changes in vascular capacitance induced by nitroglycerin (NTG) and nitroprusside were due to changes in compliance or unstressed vascular volume, doses producing similar reductions in arterial pressure (Psa) were studied on separate days in six dogs anesthetized and ventilated with pentobarbital after splenectomy during ganglion blockade with hexamethonium. Mean circulatory filling pressure (Pmcf) was determined during transient circulatory arrest induced by acetylcholine at baseline blood volumes and after increases of 5 and 10 ml/kg. Central blood volumes (CBVs, pulmonary artery to aortic root) were determined from transit times, and separately measured cardiac output (CO) was estimated by thermodilution (right atrium to pulmonary artery). NTG and nitroprusside produced similar reductions in Psa and Pmcf without significantly altering right atrial pressure (Pra), pressure gradient for venous return, or CO. Total vascular compliance was not altered, but total vascular capacitance was increased on an average of 4.0 +/- 1.4 ml/kg after NTG and 3.0 +/- 1.3 ml/kg after nitroprusside by increases in unstressed volume. Both drugs caused a variable reduction in CBV, averaging 2 ml/kg. Thus, both drugs produced a large increase in peripheral venous capacitance by increasing unstressed vascular volume without altering total vascular compliance.

Mechanism of continence after repair of posterior urethral disruption: evidence of rhabdosphincter activity.

PubMed

Whitson, Jared M; McAninch, Jack W; Tanagho, Emil A; Metro, Michael J; Rahman, Nadeem U

2008-03-01

Controversy exists regarding continence mechanisms in patients who undergo posterior urethral reconstruction after pelvic fracture. Some evidence suggests that continence after posterior urethroplasty is maintained by the bladder neck or proximal urethral mechanism without a functioning distal mechanism. We studied distal urethral sphincter activity in patients who have undergone posterior urethroplasty for pelvic fracture. A total of 12 patients who had undergone surgical repair of urethral disruption involving the prostatomembranous region underwent videourodynamics with urethral pressure profiles at rest, and during stress and hold maneuvers. Bladder pressure and urethral pressure, including proximal and distal urethral sphincter activity and pressure, were assessed in each patient. All 12 patients had daytime continence of urine postoperatively with a followup after anastomotic urethroplasty of 12 to 242 months (mean 76). Average maximum urethral pressure was 71 cm H2O. Average maximum urethral closure pressure was 61 cm H2O. The average urethral pressure seen during a brief hold maneuver was 111 cm H2O. Average functional sphincteric length was 2.5 cm. Six of the 12 patients had clear evidence of distal urethral sphincter function, as demonstrated by the profile. Continence after anastomotic urethroplasty for posttraumatic urethral strictures is maintained primarily by the proximal bladder neck. However, there is a significant contribution of the rhabdosphincter in many patients.

Minimally invasive sinus augmentation using ultrasonic piezoelectric vibration and hydraulic pressure: a multicenter retrospective study.

PubMed

Kim, Ji-Min; Sohn, Dong-Seok; Heo, Jeong-Uk; Park, Jun-Sub; Jung, Heui-Seung; Moon, Jee-Won; Lee, Ju-Hyoung; Park, In-Sook

2012-12-01

The purpose of this study was to evaluate the success rate of implants and vertical bone gain of edentulous posterior maxilla using ultrasonic piezoelectric vibration and hydraulic pressure, namely the hydrodynamic piezoelectric internal sinus elevation (HPISE) technique through a crestal approach. A total of 250 maxillary sinuses were augmented using HPISE and 353 implants (averaging 11.8 mm in length and 4.5 mm in diameter), with 12 different systems, were placed simultaneously with or without additional bone grafting. Plain radiograms and cone beam computed tomograms were taken in all patients to evaluate sinus augmentation. Membrane perforation was recorded at 10 of the 353 implant sites. The perforation rate was 2.83%. The total success rate of implantation was 97.2% after an average of 69.3 weeks of loading. The crestally approached sinus augmentation using ultrasonic piezoelectric vibration and hydraulic pressure is an additional method of maxillary sinus augmentation.

Heat transfer and pressure measurements for the SSME fuel turbine

NASA Technical Reports Server (NTRS)

Dunn, Michael G.; Kim, Jungho

1991-01-01

A measurement program is underway using the Rocketdyne two-stage Space Shuttle Main Engine (SSME) fuel turbine. The measurements use a very large shock tunnel to produce a short-duration source of heated and pressurized gas which is subsequently passed through the turbine. Within this environment, the turbine is operated at the design values of flow function, stage pressure ratio, stage temperature ratio, and corrected speed. The first stage vane row and the first stage blade row are instrumented in both the spanwise and chordwise directions with pressure transducers and heat flux gages. The specific measurements to be taken include time averaged surface pressure and heat flux distributions on the vane and blade, flow passage static pressure, flow passage total pressure and total temperature distributions, and phase resolved surface pressure and heat flux on the blade.

Carbon, land, and water footprint accounts for the European Union: consumption, production, and displacements through international trade.

PubMed

Steen-Olsen, Kjartan; Weinzettel, Jan; Cranston, Gemma; Ercin, A Ertug; Hertwich, Edgar G

2012-10-16

A nation's consumption of goods and services causes various environmental pressures all over the world due to international trade. We use a multiregional input-output model to assess three kinds of environmental footprints for the member states of the European Union. Footprints are indicators that take the consumer responsibility approach to account for the total direct and indirect effects of a product or consumption activity. We quantify the total environmental pressures (greenhouse gas emissions: carbon footprint; appropriation of biologically productive land and water area: land footprint; and freshwater consumption: water footprint) caused by consumption in the EU. We find that the consumption activities by an average EU citizen in 2004 led to 13.3 tCO(2)e of induced greenhouse gas emissions, appropriation of 2.53 gha (hectares of land with global-average biological productivity), and consumption of 179 m(3) of blue water (ground and surface water). By comparison, the global averages were 5.7 tCO(2)e, 1.23 gha, and 163 m(3) blue water, respectively. Overall, the EU displaced all three types of environmental pressures to the rest of the world, through imports of products with embodied pressures. Looking at intra-EU displacements only, the UK was the most important displacer overall, while the largest net exporters of embodied environmental pressures were Poland (greenhouse gases), France (land), and Spain (freshwater).

Effect of metatarsal pad placement on plantar pressure in people with diabetes mellitus and peripheral neuropathy.

PubMed

Hastings, Mary K; Mueller, Michael J; Pilgram, Thomas K; Lott, Donovan J; Commean, Paul K; Johnson, Jeffrey E

2007-01-01

Standard prevention and treatment strategies to decrease peak plantar pressure include a total contact insert with a metatarsal pad, but no clear guidelines exist to determine optimal placement of the pad with respect to the metatarsal head. The purpose of this study was to determine the effect of metatarsal pad location on peak plantar pressure in subjects with diabetes mellitus and peripheral neuropathy. Twenty subjects with diabetes mellitus, peripheral neuropathy, and a history of forefoot plantar ulcers were studied (12 men and eight women, mean age=57+/-9 years). CT determined the position of the metatarsal pad relative to metatarsal head and peak plantar pressures were measured on subjects in three footwear conditions: extra-depth shoes and a 1) total contact insert, 2) total contact insert and a proximal metatarsal pad, and 3) total contact insert and a distal metatarsal pad. The change in peak plantar pressure between shoe conditions was plotted and compared to metatarsal pad position relative to the second metatarsal head. Compared to the total contact insert, all metatarsal pad placements between 6.1 mm to 10.6 mm proximal to the metatarsal head line resulted in a pressure reduction (average reduction=32+/-16%). Metatarsal pad placements between 1.8 mm distal and 6.1 mm proximal and between 10.6 mm proximal and 16.8 mm proximal to the metatarsal head line resulted in variable peak plantar pressure reduction (average reduction=16+/-21%). Peak plantar pressure increased when the metatarsal pad was located more than 1.8 mm distal to the metatarsal head line. Consistent peak plantar pressure reduction occurred when the metatarsal pad in this study was located between 6 to 11 mm proximal to the metatarsal head line. Pressure reduction lessened as the metatarsal pad moved outside of this range and actually increased if the pad was located too distal of this range. Computational models are needed to help predict optimal location of metatarsal pad with a variety of sizes, shapes, and material properties.

Reliability of Baropodometry on the Evaluation of Plantar Load Distribution: A Transversal Study.

PubMed

Baumfeld, Daniel; Baumfeld, Tiago; da Rocha, Romário Lopes; Macedo, Benjamim; Raduan, Fernando; Zambelli, Roberto; Alves Silva, Thiago Alexandre; Nery, Caio

2017-01-01

Introduction . Baropodometry is used to measure the load distribution on feet during rest and walking. The aim of this study was to evaluate changes in plantar foot pressures distribution due to period of working and due to stretching exercises of the posterior muscular chain. Methods . In this transversal study, all participants were submitted to baropodometric evaluation at two different times: before and after the working period and before and after stretching the muscles of the posterior chain. Results . We analyzed a total of 54 feet of 27 participants. After the working period, there was an average increase in the forefoot pressure of 0.16 Kgf/cm 2 and an average decrease in the hindfoot pressure of 0.17 Kgf/cm 2 . After stretching the posterior muscular chain, the average increase in the forefoot pressure was 0.56 Kgf/cm 2 and the hindfoot average pressure decrease was 0.56 Kgf/cm 2 . These changes were not statistically significant. Discussion . It was reported that the strength of the Achilles tendon generates greater forefoot load transferred from the hindfoot. In our study, no significant variation in the distribution of plantar pressure was observed. It can be inferred that baropodometry was a reliable instrument to determine the plantar pressure, regardless of the tension of the posterior chain muscles.

Foot pressures during gait: a comparison of techniques for reducing pressure points.

PubMed

Lawless, M W; Reveal, G T; Laughlin, R T

2001-07-01

Various methods have been used to redistribute plantar surface foot pressure in patients with foot ulcers. This study was conducted to determine the effectiveness of four modalities (fracture walker, fracture walker with insert, and open and closed toe total contact casts) in reducing plantar foot pressure. Ten healthy, normal volunteer subjects had an F-scan sensor (ultra thin shoe insert pressure monitor) placed under the right foot. They then ambulated on a flat surface, maintaining their normal gait. Dynamic plantar pressures were averaged over 10 steps at four different sites (plantar surface of great toe, first metatarsal head, base of fifth metatarsal, and plantar heel). All subjects repeated this sequence under five different testing conditions (barefoot, with a fracture walker, fracture walker with arch support insert, open and closed toe total contact cast). Each subject's barefoot pressures were then compared with the pressures during the different modalities. All four treatment modalities significantly reduced (p < 0.05) plantar pressure at the first metatarsal head (no method was superior). The fracture walker, fracture walker with insert, and open toe total contact cast significantly reduced pressure at the heel. Pressures at the base of the fifth metatarsal and great toe were not significantly reduced with any treatment form. The fracture walker, with and without arch support, and total contact cast can effectively reduce plantar pressure at the heel and first metatarsal head.

The average cost of pressure ulcer management in a community dwelling spinal cord injury population.

PubMed

Chan, Brian C; Nanwa, Natasha; Mittmann, Nicole; Bryant, Dianne; Coyte, Peter C; Houghton, Pamela E

2013-08-01

Pressure ulcers (PUs) are a common secondary complication experienced by community dwelling individuals with spinal cord injury (SCI). There is a paucity of literature on the health economic impact of PU in SCI population from a societal perspective. The objective of this study was to determine the resource use and costs in 2010 Canadian dollars of a community dwelling SCI individual experiencing a PU from a societal perspective. A non-comparative cost analysis was conducted on a cohort of community dwelling SCI individuals from Ontario, Canada. Medical resource use was recorded over the study period. Unit costs associated with these resources were collected from publicly available sources and published literature. Average monthly cost was calculated based on 7-month follow-up. Costs were stratified by age, PU history, severity level, location of SCI, duration of current PU and PU surface area. Sensitivity analyses were also carried out. Among the 12 study participants, total average monthly cost per community dwelling SCI individual with a PU was $4745. Hospital admission costs represented the greatest percentage of the total cost (62%). Sensitivity analysis showed that the total average monthly costs were most sensitive to variations in hospitalisation costs. © 2012 The Authors. International Wound Journal © 2012 John Wiley & Sons Ltd and Medicalhelplines.com Inc.

Low cost self-made pressure distribution sensors for ergonomic chair: Are they suitable for posture monitoring?

PubMed

Martinaitis, Arnas; Daunoraviciene, Kristina

2018-05-18

Long sitting causes many health problems for people. Healthy sitting monitoring systems, like real-time pressure distribution measuring, is in high demand and many methods of posture recognition were developed. Such systems are usually expensive and hardly available for the regular user. The aim of study is to develop low cost but sensitive enough pressure sensors and posture monitoring system. New self-made pressure sensors have been developed and tested, and prototype of pressure distribution measuring system was designed. Sensors measured at average noise amplitude of a = 56 mV (1.12%), average variation in sequential measurements of the same sensor s = 17 mV (0.34%). Signal variability between sensors averaged at 100 mV (2.0%). Weight to signal dependency graph was measured and hysteresis calculated. Results suggested the use of total sixteen sensors for posture monitoring system with accuracy of < 1.5% after relaxation and repeatability of around 2%. Results demonstrate that hand-made sensor sensitivity and repeatability are acceptable for posture monitoring, and it is possible to build low cost pressure distribution measurement system with graphical visualization without expensive equipment or complicated software.

Longitudinal comparison study of pressure relief (C-Flex) vs. CPAP in OSA patients.

PubMed

Dolan, Diana C; Okonkwo, Renata; Gfullner, Florian; Hansbrough, J Randall; Strobel, Richard J; Rosenthal, Leon

2009-03-01

Continuous positive airway pressure (CPAP) devices with the option of flexible pressure delivery (e.g., C-Flex) are thought to provide an improved degree of comfort and result in better therapeutic adherence while maintaining standard CPAP efficacy. The purpose of this study was to compare adherence and subjective measures of comfort between C-Flex and CPAP treatment. The study was an international, multisite, single-blinded study with participants randomized to either C-Flex or CPAP. Participants completed subjective measures of sleepiness and comfort at baseline, and at 30-, 90-, and 180-day follow-ups. Additionally, compliance data were downloaded from the device at each follow-up. Repeated measures analysis of variance was used to assess the effects of treatment. There were 138 men and 46 women (average age of 48 +/- 9.2, average Epworth Sleepiness Scale score of 14.9 +/- 3.6, and average diagnostic apnea/hypopnea index (AHI) of 51.9 +/- 27.7). C-Flex and CPAP groups were comparable on baseline measures, achieved comparable AHI on titration, and had comparable PAP pressure requirements. C-Flex users had comparable average hours of use per night and total nights of use across the study, but had a trend (p < .07) toward achieving greater total hours of utilization. While both groups had comparable decreases in sleepiness, C-Flex users reported on visual analog scales greater comfort (64.3 vs. 57.4; p = .01). The results of this study demonstrated that C-Flex has comparable resolution of respiratory indices and adherence. Furthermore, C-Flex users reported greater mask comfort.

Vortex Generators in a Two-Dimensional, External-Compression Supersonic Inlet

NASA Technical Reports Server (NTRS)

Baydar, Ezgihan; Lu, Frank K.; Slater, John W.

2016-01-01

Vortex generators within a two-dimensional, external-compression supersonic inlet for Mach 1.6 were investigated to determine their ability to increase total pressure recovery, reduce total pressure distortion, and improve the boundary layer. The vortex generators studied included vanes and ramps. The geometric factors of the vortex generators studied included height, length, spacing, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated through the computational solution of the steady-state Reynolds-averaged Navier-Stokes equations on multi-block, structured grids. The vortex generators were simulated by either gridding the geometry of the vortex generators or modeling the vortices generated by the vortex generators. The inlet performance was characterized by the inlet total pressure recovery, total pressure distortion, and incompressible shape factor of the boundary-layer at the engine face. The results suggested that downstream vanes reduced the distortion and improved the boundary layer. The height of the vortex generators had the greatest effect of the geometric factors.

Evaluation of eating and rumination behaviour in cows using a noseband pressure sensor

PubMed Central

2013-01-01

Background An automated technique for recording eating and rumination behaviour was evaluated in ten lactating Brown Swiss cows by comparing data obtained from a pressure sensor with data obtained via direct observation over a 24-hour period. The recording device involved a pressure sensor integrated in the noseband of a halter. The analysed variables included number and duration of individual rumination, eating and resting phases, total daily length of these phases and number of cuds chewed per day. Results Eating and rumination phases were readily differentiated based on characteristic pressure profiles. Chewing movements during rumination were regular and generated regular waveforms with uniform amplitudes, whereas eating generated irregular waveforms with variable amplitudes. There was complete or almost complete agreement and no significant differences between data obtained via direct observation and pressure sensor technique. Both methods yielded an average of 16 daily eating phases with a mean duration of 28.3 minutes. Total time spent eating was 445.0 minutes for direct observation and 445.4 minutes for the pressure sensor technique. Both techniques recorded an average of 13.3 rumination phases with a mean duration of 30.3 (direct observation) and of 30.2 (pressure sensor) minutes. Total time spent ruminating per day, number of cuds per day and chewing cycles per cud were 389.3 and 388.3 minutes, 410.1 and 410.0 and 60.0 and 60.3 for direct observation and pressure sensor technique, respectively. There was a significant difference between the two methods with respect to mean number of chewing cycles per day (24′669, direct observation vs. 24′751, pressure sensor, P < 0.05, paired t-test). There were strong correlations between the two recording methods with correlation coefficients ranging from 0.98 to 1.00. Conclusions The results confirmed that measurements of eating and rumination variables obtained via the pressure sensor technique are in excellent agreement with data obtained via direct observation. PMID:23941142

Surface modification of Monel K-500 as a means of reducing friction and wear in high-pressure oxygen

NASA Technical Reports Server (NTRS)

Gunaji, Mohan; Stoltzfus, Joel M.; Schoenman, Leonard; Kazaroff, John

1989-01-01

A study is conducted of the tribological characteristics of Monel K-500 during rubbing in a high pressure oxygen atmosphere, upon surface treatment by ion-implanted oxygen, chromium, lead, and silver, as well as electrolyzed chromium and an electroless nickel/SiC composite. The electrolyzed chromium dramatically increased total sample wear, while other surface treatments affected sample wear only moderately. Although the ion-implant treatments reduced the average coefficient of friction at low contact pressure, higher contact pressures eliminated this improvement.

Home blood pressure variability on one occasion is a novel factor associated with arterial stiffness in patients with type 2 diabetes.

PubMed

Fukui, Michiaki; Ushigome, Emi; Tanaka, Muhei; Hamaguchi, Masahide; Tanaka, Toru; Atsuta, Haruhiko; Ohnishi, Masayoshi; Oda, Yohei; Hasegawa, Goji; Nakamura, Naoto

2013-03-01

Recent studies have suggested that not only mean blood pressure but also variability in blood pressure might be related to cardiovascular disease. The aim of this study was to investigate the association between home blood pressure variability on one occasion and markers of arterial stiffness in patients with type 2 diabetes. We investigated the relationship between the s.d. of clinic- or home-measured systolic blood pressure on one occasion and pulse wave velocity (PWV) in 332 patients with type 2 diabetes, and we evaluated whether the SD of clinic- or home-measured systolic blood pressure on one occasion was an independent determinant of PWV by multivariate linear regression analysis, after adjustment for known risk factors for arterial stiffness, including sex, age, duration of diabetes, body mass index, hemoglobin A1c, serum total cholesterol, triglycerides, smoking status, drinking alcohol, presence of antihypertensive medication, average systolic blood pressure and heart rate. Age, average morning home-measured systolic blood pressure, heart rate and PWV (r=0.259, P<0.0001) were positively correlated with the s.d. of morning home blood pressure on one occasion. Multiple regression analysis demonstrated that age, average morning home-measured systolic blood pressure (P=0.0019), heart rate and the s.d. of morning home-measured systolic blood pressure on one occasion (P=0.0159) were independently associated with PWV. In conclusion, home blood pressure variability on one occasion was correlated with PWV, independent of other known risk factors, in Japanese patients with type 2 diabetes.

Ground Impingement of a Fan Jet Exhaust Plume

DTIC Science & Technology

1978-05-01

ground plane to avoid a possible interaction between the ground-deflected exhaust and the fan j .t engine inlet. Two pitot pressure rakes , shown on the...Pressure signals from the two rakes (total of 18 pitot tubes) were read sequentially with a Scannivalve system, time-averaged, and displayed on a pen...taken from the inner anid outer rakes with the ground plane normal to the flow at h/d f 2. Pitot pressures from each rake were normalized by the

[Effects of acupuncture on circadian rhythm of blood pressure in patients with essential hypertension].

PubMed

Lei, Yun; Jin, Jiu; Ban, Haipeng; Du, Yuzheng

2017-11-12

To observe the effects of acupuncture combined with medication on circadian rhythm of blood pressure in patients with essential hypertension. Sixty-four patients of essential hypertension were randomly divided into an observation group and a control group, 32 cases in each group. All the patients maintained original treatment (taking antihypertensive medication); the patients in the observation group were treated with acupuncture method of " Huoxue Sanfeng , Shugan Jianpi ", once a day, five times per week, for totally 6 weeks (30 times). The circadian rhythm of blood pressure and related dynamic parameters were observed before and after treatment in the two groups. (1) The differences of daytime average systolic blood pressure (dASBP), daytime average diastolic blood pressure (dADBP), nighttime average systolic blood pressure (nASBP) and circadian rhythm of systolic blood pressure before and after treatment were significant in the observation group (all P <0.05); the differences of circadian rhythm of blood pressure and related dynamic parameters before and after treatment were insignificant in the control group (all P >0.05). The nASBP and circadian rhythm of systolic blood pressure in the observation group were significantly different from those in the control group (all P <0.05). (2) After the treatment, the spoon-shaped rate of circadian rhythm of blood pressure in the observation group was higher than that in the control group ( P <0.05). The acupuncture combined with medication could effectively improve the circadian rhythm of blood pressure and related dynamic parameters in patients with essential hypertension.

Biometric Screening and Future Employer Medical Costs: Is It Worth It to Know?

PubMed

Vanichkachorn, Greg; Marchese, Maya; Roy, Brad; Opel, Gordon

2017-12-01

To study the relationship between a biometric wellness data and future/actual medical costs. A relationship between total cholesterol to high density lipoprotein ratio, blood pressure, and blood glucose and medical costs, based on analysis of claims data, was explored in 1834 employees that had both wellness program biometric and claims data in 2016. Increased total cholesterol to HDL ratio is strongly associated with increased average costs (P < 0.01). Similarly, an increased glucose level is strongly associated with increased average costs (P = 0.001). There was no evidence of a relationship between elevated blood pressure and higher costs. By investing in an employer-sponsored biometric screening of full cholesterol and glucose profiles, medium-sized employers can identify high-risk employees who are expected to incur significantly higher healthcare costs, as compared with low-risk level employees, and improve treatment outcomes.

Global effects of land use on local terrestrial biodiversity.

PubMed

Newbold, Tim; Hudson, Lawrence N; Hill, Samantha L L; Contu, Sara; Lysenko, Igor; Senior, Rebecca A; Börger, Luca; Bennett, Dominic J; Choimes, Argyrios; Collen, Ben; Day, Julie; De Palma, Adriana; Díaz, Sandra; Echeverria-Londoño, Susy; Edgar, Melanie J; Feldman, Anat; Garon, Morgan; Harrison, Michelle L K; Alhusseini, Tamera; Ingram, Daniel J; Itescu, Yuval; Kattge, Jens; Kemp, Victoria; Kirkpatrick, Lucinda; Kleyer, Michael; Correia, David Laginha Pinto; Martin, Callum D; Meiri, Shai; Novosolov, Maria; Pan, Yuan; Phillips, Helen R P; Purves, Drew W; Robinson, Alexandra; Simpson, Jake; Tuck, Sean L; Weiher, Evan; White, Hannah J; Ewers, Robert M; Mace, Georgina M; Scharlemann, Jörn P W; Purvis, Andy

2015-04-02

Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.

Global effects of land use on local terrestrial biodiversity

NASA Astrophysics Data System (ADS)

Newbold, Tim; Hudson, Lawrence N.; Hill, Samantha L. L.; Contu, Sara; Lysenko, Igor; Senior, Rebecca A.; Börger, Luca; Bennett, Dominic J.; Choimes, Argyrios; Collen, Ben; Day, Julie; de Palma, Adriana; Díaz, Sandra; Echeverria-Londoño, Susy; Edgar, Melanie J.; Feldman, Anat; Garon, Morgan; Harrison, Michelle L. K.; Alhusseini, Tamera; Ingram, Daniel J.; Itescu, Yuval; Kattge, Jens; Kemp, Victoria; Kirkpatrick, Lucinda; Kleyer, Michael; Correia, David Laginha Pinto; Martin, Callum D.; Meiri, Shai; Novosolov, Maria; Pan, Yuan; Phillips, Helen R. P.; Purves, Drew W.; Robinson, Alexandra; Simpson, Jake; Tuck, Sean L.; Weiher, Evan; White, Hannah J.; Ewers, Robert M.; Mace, Georgina M.; Scharlemann, Jörn P. W.; Purvis, Andy

2015-04-01

Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.

Triacylglycerols profiling in plant oils important in food industry, dietetics and cosmetics using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

PubMed

Lísa, Miroslav; Holcapek, Michal

2008-07-11

Optimized non-aqueous reversed-phase high-performance liquid chromatography method using acetonitrile-2-propanol gradient elution and the column coupling in the total length of 45 cm has been applied for the high resolution separation of plant oils important in food industry, dietetics and cosmetics. Positive-ion atmospheric pressure chemical ionization mass spectrometry is used for the unambiguous identification and also the reliable quantitation with the response factors approach. Based on the precise determination of individual triacyglycerol concentrations, the calculation of average parameters important in the nutrition is performed, i.e. average carbon number, average double bond number, relative concentrations of essential, saturated, monounsaturated and polyunsaturated fatty acids. Results are reported in the form of both chromatographic fingerprints and tables containing relative concentrations for all triacylglycerols and fatty acids in individual samples. In total, 264 triacylglycerols consisting of 28 fatty acids with the alkyl chain length from 6 to 26 carbon atoms and 0 to 4 double bonds have been identified in 26 industrial important plant oils.

Time-dependent local and average structural evolution of δ-phase 239Pu-Ga alloys

DOE PAGES

Smith, Alice I.; Page, Katharine L.; Siewenie, Joan E.; ...

2016-08-05

Here, plutonium metal is a very unusual element, exhibiting six allotropes at ambient pressure, between room temperature and its melting point, a complicated phase diagram, and a complex electronic structure. Many phases of plutonium metal are unstable with changes in temperature, pressure, chemical additions, or time. This strongly affects structure and properties, and becomes of high importance, particularly when considering effects on structural integrity over long periods of time [1]. This paper presents a time-dependent neutron total scattering study of the local and average structure of naturally aging δ-phase 239Pu-Ga alloys, together with preliminary results on neutron tomography characterization.

Selected meteorological data for an arid site near Beatty, Nye County, Nevada, calendar years 1990 and 1991

USGS Publications Warehouse

Wood, James L.; Andraski, Brian J.

1995-01-01

Selected meteorological data were collected at a study site adjacent to a low-level radioactive-waste burial facility near Beatty, Nevada, for calendar years 1990 and 1991. Data were collected in support of ongoing studies to estimate the potential for downward movement of radionuclides into the unsaturated sediments beneath waste-burial trenches at the facility. The data include air temperature, relative humidity, vapor pressure, incident solar radiation, windspeed, wind direction, barometric pressure, and precipitation. The data are summarized in tables and graphs.Instrumentation used at the site is discussed. The discussion includes the type, reported accuracy, and mounting height of each sensor.In 1990, the average hourly air temperatures ranged from -16.2 degrees Celsius, in December, to 44.2 degrees Celsius, in July. Hourly averaged relative humidity ranged from 6 percent to more than 90 percent. Hourly vapor pressures ranged from 0.08 to 1.84 kilopascals. Daily maximum incident solar radiation values ranged from 192 to 1,028 watts per square meter. Daily mean windspeed ranged from less than 1 to 8.7 meters per second. Wind direction was primarily from the northwest in fall, winter, and spring and varied from southeast, southwest, or northwest during the summer. Hourly barometric pressures ranged from 99.47 to 103.12 kilopascals. Total precipitation for 1990 was 32.4 millimeters; almost 45 percent was in September.In 1991, the average hourly air temperatures ranged from -9.2 degrees Celsius, in January, to 43.7 degrees Celsius, in July. Hourly averaged relative humidity ranged from 3 percent to more than 95 percent. Hourly vapor pressures ranged from 0.07 to 2.22 kilopascals. Daily maximum incident solar radiation values ranged from 143 to 1,041 watts per square meter. Daily mean windspeed ranged from 1.2 to 8.4 meters per second. Wind direction was primarily from the northwest in fall, winter, and spring and varied from southeast, southwest, or northwest during the summer. Hourly barometric pressures ranged from 99.52 to 103.40 kilopascals. Total precipitation for 1991 was 103.6 millimeters; almost 60 percent was in March.

Correlation of residual strength with acoustic emission from impact-damaged composite structures under constant biaxial load

NASA Astrophysics Data System (ADS)

Hamstad, M. A.; Whittaker, J. W.; Brosey, W. D.

1992-01-01

Small, filament-wound, Kevlar/epoxy, biaxial test specimens were subjected to various levels of impact damage. The specimens were pressurized in a proof test cycle to 58 percent of their nominal, undamaged strength and then pressurized to failure. Acoustic emission data were gathered by multiple sensors during a 10 minute hold at peak proof pressure. Post-test filtering of the data was performed to study composite behavior in the damaged region and other areas. The rate and total amount of AE produced depends on the duration of the static load and degree of damage. The concept of the event rate moment is introduced as a method of quantifying a structure's total AE behavior when under static load. Average event rate, total long duration events, and event rate moments provided various degrees of correlation between AE and residual strength.

[Association between distribution of bacillary dysentery and meteorological factors in Beijing, 2004-2015].

PubMed

Du, Z; Zhang, J; Lu, J X; Lu, L P

2018-05-10

Objective: To analyze the distribution characteristics of bacillary dysentery in Beijing during 2004-2015 and evaluate the influence of meteorological factors on the temporal and spatial distribution of bacillary dysentery. Methods: The incidence data of bacterial dysentery and meteorological data in Beijing from 2004 to 2015 were collected. Descriptive epidemiological analysis was conducted to study the distribution characteristics of bacterial dysentery. Linear correlation analysis and multiple linear regression analysis were carried out to investigate the relationship between the incidence of bacillary dysentery and average precipitation, average air temperature, sunshine hours, average wind speed, average air pressure, gale and rain days. Results: A total of 280 704 cases of bacterial dysentery, including 36 deaths, were reported from 2004 to 2015 in Beijing, the average annual incidence was 130.15/100 000. The annual incidence peak was mainly between May and October, the cases occurred during this period accounted for 80.75 % of the total, and the incidence was highest in age group 0 year. The population distribution showed that most cases were children outside child care settings and students, and the sex ratio of the cases was 1.22∶1. The reported incidence of bacillary dysentery was positively associated with average precipitation, average air temperature and rain days with the correlation coefficients of 0.931, 0.878 and 0.888, but it was negatively associated with the average pressure, the correlation coefficient was -0.820. Multiple linear regression equation for fitting analysis of bacillary dysentery and meteorological factors was Y =3.792+0.162 X (1). Conclusion: The reported incidence of bacillary dysentery in Beijing was much higher than national level. The annual incidence peak was during July to August, and the average precipitation was an important meteorological factor influencing the incidence of bacillary dysentery.

Abnormal cardiovascular responses induced by localized high power microwave exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, S.-T; Brown, D.O.; Johnson, C.E.

1992-05-01

A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz and 16 Hz pulsemodulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in themore » neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power but not to the lower average power microwaves. Depression of pulse pressure, an indication of a decrease in stroke volume, and increased or decreased heart rate were noted in presence of whole-body hyperthermia. The cardiac output of those animals exposed to higher average power microwaves was considered to be below normal as hypothesized. Decreased cardiac output and normal mean arterial pressure resulted in an increase in the total peripheral resistance which was contrary to the anticipated thermal response of animals.« less

Attitudes of surgical nurses towards pressure ulcer prevention.

PubMed

Ünver, Seher; Fındık, Ümmü Yıldız; Özkan, Zeynep Kızılcık; Sürücü, Çağla

2017-11-01

Nurses play the key role in prevention of pressure ulcers, and negative attitudes of them may affect preventive care strategies. This research aimed to identify surgical nurses' attitudes towards pressure ulcer prevention. A descriptive and cross-sectional study design was used to collect data between March 31-May 16, 2016 on 101 voluntary nurses (66.01% of all nurses) working in surgical units of a university hospital in Turkey. "Attitude towards Pressure Ulcer Prevention Instrument" and "Nurse Information Form" were used to investigate nurses' attitude toward preventing pressure ulcer. Descriptive statistics, Mann-Whitney U test, independent samples t-test, Pearson's chi-squared, and correlation tests were used to analyse the data. The mean age of nurses' was 32.0 ± 6.3 years and, the average duration of clinical experience was 72.3 ± 61 months. A total of 54.5% were working in surgical wards and, 40.6% gained additional education about pressure ulcer care. The mean total attitude score was found to be 80.5% (41.8 ± 4.8). Previous education significantly affected the total attitude score of nurses (p < 0.05). The total scale score showed that surgical nurses had a positive attitude towards pressure ulcer prevention and nurses who had previous education about pressure ulcer care has higher attitude score than who had not. It is recommended that effective in-service education programs be developed at hospitals or that nurses be required to attend courses to help them to improve their pressure ulcer care. Copyright © 2017. Published by Elsevier Ltd.

Pressure-Aware Control Layer Optimization for Flow-Based Microfluidic Biochips.

PubMed

Wang, Qin; Xu, Yue; Zuo, Shiliang; Yao, Hailong; Ho, Tsung-Yi; Li, Bing; Schlichtmann, Ulf; Cai, Yici

2017-12-01

Flow-based microfluidic biochips are attracting increasing attention with successful biomedical applications. One critical issue with flow-based microfluidic biochips is the large number of microvalves that require peripheral control pins. Even using the broadcasting addressing scheme, i.e., one control pin controls multiple microvalves simultaneously, thousands of microvalves would still require hundreds of control prins, which is unrealistic. To address this critical challenge in control scalability, the control-layer multiplexer is introduced to effectively reduce the number of control pins into log scale of the number of microvalves. There are two practical design issues with the control-layer multiplexer: (1) the reliability issue caused by the frequent control-valve switching, and (2) the pressure degradation problem caused by the control-valve switching without pressure refreshing from the pressure source. This paper addresses these two design issues by the proposed Hamming-distance-based switching sequence optimization method and the XOR-based pressure refreshing method. Simulation results demonstrate the effectiveness and efficiency of the proposed methods with an average 77.2% (maximum 89.6%) improvement in total pressure refreshing cost, and an average 88.5% (maximum 90.0%) improvement in pressure deviation.

Gastroesophageal pressure gradients in gastroesophageal reflux disease: relations with hiatal hernia, body mass index, and esophageal acid exposure.

PubMed

de Vries, Durk R; van Herwaarden, Margot A; Smout, André J P M; Samsom, Melvin

2008-06-01

The roles of intragastric pressure (IGP), intraesophageal pressure (IEP), gastroesophageal pressure gradient (GEPG), and body mass index (BMI) in the pathophysiology of gastroesophageal reflux disease (GERD) and hiatal hernia (HH) are only partly understood. In total, 149 GERD patients underwent stationary esophageal manometry, 24-h pH-metry, and endoscopy. One hundred three patients had HH. Linear regression analysis showed that each kilogram per square meter of BMI caused a 0.047-kPa increase in inspiratory IGP (95% confidence interval [CI] 0.026-0.067) and a 0.031-kPa increase in inspiratory GEPG (95% CI 0.007-0.055). Each kilogram per square meter of BMI caused expiratory IGP to increase with 0.043 kPa (95% CI 0.025-0.060) and expiratory IEP with 0.052 kPa (95% CI 0.027-0.077). Each added year of age caused inspiratory IEP to decrease by 0.008 kPa (95% CI -0.015-0.001) and inspiratory GEPG to increase by 0.008 kPa (95% CI 0.000-0.015). In binary logistic regression analysis, HH was predicted by inspiratory and expiratory IGP (odds ratio [OR] 2.93 and 2.62, respectively), inspiratory and expiratory GEPG (OR 3.19 and 2.68, respectively), and BMI (OR 1.72/5 kg/m(2)). In linear regression analysis, HH caused an average 5.09% increase in supine acid exposure (95% CI 0.96-9.22) and an average 3.46% increase in total acid exposure (95% CI 0.82-6.09). Each added year of age caused an average 0.10% increase in upright acid exposure and a 0.09% increase in total acid exposure (95% CI 0.00-0.20 and 0.00-0.18). BMI predicts IGP, inspiratory GEPG, and expiratory IEP. Age predicts inspiratory IEP and GEPG. Presence of HH is predicted by IGP, GEPG, and BMI. GEPG is not associated with acid exposure.

IFCPT S-Duct Grid-Adapted FUN3D Computations for the Third Propulsion Aerodynamics Works

NASA Technical Reports Server (NTRS)

Davis, Zach S.; Park, M. A.

2017-01-01

Contributions of the unstructured Reynolds-averaged Navier-Stokes code, FUN3D, to the 3rd AIAA Propulsion Aerodynamics Workshop are described for the diffusing IFCPT S-Duct. Using workshop-supplied grids, results for the baseline S-Duct, baseline S-Duct with Aerodynamic Interface Plane (AIP) rake hardware, and baseline S-Duct with flow control devices are compared with experimental data and results computed with output-based, off-body grid adaptation in FUN3D. Due to the absence of influential geometry components, total pressure recovery is overpredicted on the baseline S-Duct and S-Duct with flow control vanes when compared to experimental values. An estimate for the exact value of total pressure recovery is derived for these cases given an infinitely refined mesh. When results from output-based mesh adaptation are compared with those computed on workshop-supplied grids, a considerable improvement in predicting total pressure recovery is observed. By including more representative geometry, output-based mesh adaptation compares very favorably with experimental data in terms of predicting the total pressure recovery cost-function; whereas, results computed using the workshop-supplied grids are underpredicted.

Porous membrane utilization in plant nutrient delivery

NASA Technical Reports Server (NTRS)

Dreschel, T. W.; Hinkle, C. R.; Prince, R. P.; Knott, W. M., III

1987-01-01

A spacecraft hydroponic plant growth unit of tubular configuration, employing a microporous membrane as a capilary interface between plant roots and a nutrient solution, is presented. All three of the experimental trials undertaken successfully grew wheat from seed to harvest. Attention is given to the mass/seed, number of seeds/head, ratio of seed dry mass to total plant dry mass, production of tillers, and mass of seed/plant. Dry matter production is found to be reduced with increasing suction pressure; this is true for both average seed and average total dry matter/plant. This may be due to a reduction in water and nutrient availability through the microporous membrane.

Numerical Investigation of a Model Scramjet Combustor Using DDES

NASA Astrophysics Data System (ADS)

Shin, Junsu; Sung, Hong-Gye

2017-04-01

Non-reactive flows moving through a model scramjet were investigated using a delayed detached eddy simulation (DDES), which is a hybrid scheme combining Reynolds averaged Navier-Stokes scheme and a large eddy simulation. The three dimensional Navier-Stokes equations were solved numerically on a structural grid using finite volume methods. An in-house was developed. This code used a monotonic upstream-centered scheme for conservation laws (MUSCL) with an advection upstream splitting method by pressure weight function (AUSMPW+) for space. In addition, a 4th order Runge-Kutta scheme was used with preconditioning for time integration. The geometries and boundary conditions of a scramjet combustor operated by DLR, a German aerospace center, were considered. The profiles of the lower wall pressure and axial velocity obtained from a time-averaged solution were compared with experimental results. Also, the mixing efficiency and total pressure recovery factor were provided in order to inspect the performance of the combustor.

Optimum data analysis procedures for Titan 4 and Space Shuttle payload acoustic measurements during lift-off

NASA Technical Reports Server (NTRS)

Piersol, Allan G.

1991-01-01

Analytical expressions have been derived to describe the mean square error in the estimation of the maximum rms value computed from a step-wise (or running) time average of a nonstationary random signal. These analytical expressions have been applied to the problem of selecting the optimum averaging times that will minimize the total mean square errors in estimates of the maximum sound pressure levels measured inside the Titan IV payload fairing (PLF) and the Space Shuttle payload bay (PLB) during lift-off. Based on evaluations of typical Titan IV and Space Shuttle launch data, it has been determined that the optimum averaging times for computing the maximum levels are (1) T (sub o) = 1.14 sec for the maximum overall level, and T(sub oi) = 4.88 f (sub i) (exp -0.2) sec for the maximum 1/3 octave band levels inside the Titan IV PLF, and (2) T (sub o) = 1.65 sec for the maximum overall level, and T (sub oi) = 7.10 f (sub i) (exp -0.2) sec for the maximum 1/3 octave band levels inside the Space Shuttle PLB, where f (sub i) is the 1/3 octave band center frequency. However, the results for both vehicles indicate that the total rms error in the maximum level estimates will be within 25 percent the minimum error for all averaging times within plus or minus 50 percent of the optimum averaging time, so a precise selection of the exact optimum averaging time is not critical. Based on these results, linear averaging times (T) are recommended for computing the maximum sound pressure level during lift-off.

The effective forces transmitted by high-speed, low-amplitude thoracic manipulation.

PubMed

Herzog, W; Kats, M; Symons, B

2001-10-01

Twenty asymptomatic volunteers each received three spinal manipulative treatments to the thoracic spine. The treatments consisted of a straight posterior-to-anterior high-speed, low-amplitude thrust to the transverse process of T3-T10 using a reinforced hypothenar contact. All treatments were given by a full-time practicing clinician with 3 years of experience. The primary objective of this study was to quantify local measures of loading applied by the clinician on the volunteers during spinal manipulative treatments and to compare these local measures of loading with previously described global measures. The sparse information on the mechanics of spinal manipulative treatments deals exclusively with global force or pressure measurements. On the basis of these global data, incorrect conclusions may be drawn about the beneficial effects of spinal manipulative therapy, the loading of internal structures, and the risks associated with these treatments. Twenty asymptomatic subjects each received three posterior-to-anterior, high-speed, low-amplitude spinal manipulative treatments to the transverse process of the thoracic spine. Total force, local force, contact area, peak pressure, and average pressure at the contact interface between clinician and subject were measured continuously by use of a thin, flexible pressure pad. Local and global measures of loading were compared and analyzed by use of nonparametric statistics (alpha = 0.01). The average peak total force was 238.2 N. The average peak local force over a target area of 25 mm2 was 5 N, indicating that global measures of loading vastly overestimate the local effective forces at the target site. The peak pressure point moved, on average, 9.8 mm during the course of the manipulation. To the authors' best knowledge, this is the first study to quantify local, effective measures of loading and compare them with the global measures typically used. The conclusions are limited because the study used a single clinician. The effective loading of specific target sites is much smaller than the global measures might suggest. This result occurs because as the forces during spinal manipulative treatment increase, so does the contact area; therefore, much of the total treatment force is taken up by non-target-specific tissues. Because of the vast discrepancy between the global and local measures of loading, it is suggested that risk-benefit assessments of high-speed, low-amplitude spinal manipulative treatments should be made, including local measures of loading. Finally, because theoretical approaches and the inverse dynamics approach can provide only global measures of loading, the results of such studies should be interpreted with caution.

Evolution of the Orszag-Tang vortex system in a compressible medium. I - Initial average subsonic flow

NASA Technical Reports Server (NTRS)

Dahlburg, R. B.; Picone, J. M.

1989-01-01

The results of fully compressible, Fourier collocation, numerical simulations of the Orszag-Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2-0.6. These values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.

Evolution of the Orszag--Tang vortex system in a compressible medium. I. Initial average subsonic flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahlburg, R.B.; Picone, J.M.

In this paper the results of fully compressible, Fourier collocation, numerical simulations of the Orszag--Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2--0.6. Thesemore » values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.« less

Physical parameter estimation from porcine ex vivo vocal fold dynamics in an inverse problem framework.

PubMed

Gómez, Pablo; Schützenberger, Anne; Kniesburges, Stefan; Bohr, Christopher; Döllinger, Michael

2018-06-01

This study presents a framework for a direct comparison of experimental vocal fold dynamics data to a numerical two-mass-model (2MM) by solving the corresponding inverse problem of which parameters lead to similar model behavior. The introduced 2MM features improvements such as a variable stiffness and a modified collision force. A set of physiologically sensible degrees of freedom is presented, and three optimization algorithms are compared on synthetic vocal fold trajectories. Finally, a total of 288 high-speed video recordings of six excised porcine larynges were optimized to validate the proposed framework. Particular focus lay on the subglottal pressure, as the experimental subglottal pressure is directly comparable to the model subglottal pressure. Fundamental frequency, amplitude and objective function values were also investigated. The employed 2MM is able to replicate the behavior of the porcine vocal folds very well. The model trajectories' fundamental frequency matches the one of the experimental trajectories in [Formula: see text] of the recordings. The relative error of the model trajectory amplitudes is on average [Formula: see text]. The experiments feature a mean subglottal pressure of 10.16 (SD [Formula: see text]) [Formula: see text]; in the model, it was on average 7.61 (SD [Formula: see text]) [Formula: see text]. A tendency of the model to underestimate the subglottal pressure is found, but the model is capable of inferring trends in the subglottal pressure. The average absolute error between the subglottal pressure in the model and the experiment is 2.90 (SD [Formula: see text]) [Formula: see text] or [Formula: see text]. A detailed analysis of the factors affecting the accuracy in matching the subglottal pressure is presented.

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2010 CFR

2010-04-01

... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION... polyethylene has a minimum number average molecular weight of 1,200, as determined by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total oxygen; and has an acid value of 9...

Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection.

PubMed

Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K

2015-10-15

A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

Navier-Stokes analysis of an oxidizer turbine blade with tip clearance

NASA Technical Reports Server (NTRS)

Gibeling, Howard J.; Sabnis, Jayant S.

1992-01-01

The Gas Generator Oxidizer Turbine (GGOT) Blade is being analyzed by various investigators under the NASA MSFC sponsored Turbine Stage Technology Team design effort. The present work concentrates on the tip clearance region flow and associated losses; however, flow details for the passage region are also obtained in the simulations. The present calculations simulate the rotor blade row in a rotating reference frame with the appropriate coriolis and centrifugal acceleration terms included in the momentum equation. The upstream computational boundary is located about one axial chord from the blade leading edge. The boundary conditions at this location were determined by using a Euler analysis without the vanes to obtain approximately the same flow profiles at the rotor as were obtained with the Euler stage analysis including the vanes. Inflow boundary layer profiles are then constructed assuming the skin friction coefficient at both the hub and the casing. The downstream computational boundary is located about one axial chord from the blade trailing edge, and the circumferentially averaged static pressure at this location was also obtained from the Euler analysis. Results were obtained for the 3-D baseline GGOT geometry at the full scale design Reynolds number. Details of the clearance region flow behavior and blade pressure distributions were computed. The spanwise variation in blade loading distributions are shown, and circumferentially averaged spanwise distributions of total pressure, total temperature, Mach number, and flow angle are shown at several axial stations. The spanwise variation of relative total pressure loss shows a region of high loss in the region near the casing. Particle traces in the near tip region show vortical behavior of the fluid which passes through the clearance region and exits at the downstream edge of the gap.

Pedobarography in diagnosis and clinical application.

PubMed

Skopljak, Amira; Muftic, Mirsad; Sukalo, Aziz; Masic, Izet; Zunic, Lejla

2014-12-01

Pedobarography as a new diagnostic tool enables measuring the pressure between the foot and the floor during dynamic loading. Dynamic analysis of the foot shows advantage over static analysis due to its capabilities for detecting high load points in certain diseases and in certain phases of walking. Pedobarography as a new method in the context of rehabilitation include wide range of clinical entities. To show the advantages of pedobarography as new diagnostic and rehabilitation method in prevention programs. A prospective study included 100 patients with diabetes mellitus type 2. Research was conducted in the Primary Health Care Center of the Sarajevo Canton and the Center for Physical Medicine and Rehabilitation. The test parameters were: Test of balance-symmetric load for the test, the number of comorbidity, clinical examination of foot deformity, test with 10 g monofilament, HbA1c. From the total sample 45 patients (Group I) were selected, aged 50-65 years, which underwent pedobarography (on the appliance Novel Inc., Munich with EMED™ platform) and robotic fabrication of individual orthopedic insoles, followed by control pedobarography. Plantar pressure was determined using standard pedobarography, computer recorded parameters: peak pressure (kPa), force (Ns), area (cm). The average age of the respondents was 59.4±11.38 years; altered results on the balance test were present in 34% of patients; 61% of respondents have ≤2 comorbidity. In the total sample, the average number of foot deformity was 2.84. Flat feet have 66% of respondents, and valgus position 57%. The average HbA1c values were 7.783±1.58% (min.5-max.15.0). All subjects (45) after the first, and after the second measurement of peak pressure, have values above 200 kPa, or are in the designated zone of peak pressure that needs to be corrected. In a study was determined the correlation between the number of deformities and peak pressure, the number of deformities and the area upon which plantar pressure act, test with 10g monofilament and peak pressure. Within the framework of prevention programs early diagnosis, detection of sensitivity disorders, adequate treatment and taking load from the feet with the help of pedobarography, are of great importance for the patient suffering from diabetes.

The turn team: a novel strategy for reducing pressure ulcers in the surgical intensive care unit.

PubMed

Still, Mary D; Cross, Linda C; Dunlap, Martha; Rencher, Rugenia; Larkins, Elizabeth R; Carpenter, David L; Buchman, Timothy G; Coopersmith, Craig M

2013-03-01

Pressure ulcers cause significant morbidity and mortality in the surgical intensive care unit (SICU). The purpose of this study was to determine if a dedicated team tasked with turning and repositioning all hemodynamically stable SICU patients could decrease the formation of pressure ulcers. A total of 507 patients in a 20-bed SICU in a university hospital were assessed for pressure ulcers using a point prevalence strategy, between December 2008 and September 2010, before and after implementation of a team tasked with turning and repositioning all hemodynamically stable patients every 2 hours around the clock. At baseline, when frequent turning was encouraged but not required, a total of 42 pressure ulcers were identified in 278 patients. After implementation of the turn team, a total of 12 pressure ulcers were identified in 229 patients (p < 0.0001). The preintervention group included 34 stage I and II ulcers and 8 higher stage ulcers. After implementation of the turn team, there were 7 stage I and II ulcers and 5 higher stage ulcers. The average Braden score was 16.5 in the preintervention group and 13.4 in the postintervention group (p = 0.04), suggesting that pressure ulcers were occurring in higher risk patients after implementation of the turn team. A team dedicated to turning SICU patients every 2 hours dramatically decreased the incidence of pressure ulcers. The majority of stage I and stage II ulcers appear to be preventable with an aggressive intervention aimed at pressure ulcer prevention. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Plantar pressures determinants in mild Hallux Valgus.

PubMed

Martínez-Nova, Alfonso; Sánchez-Rodríguez, Raquel; Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Leal-Muro, Alejo; Pedrera-Zamorano, Juan Diego

2010-07-01

While podobarometric techniques have been applied to the study of pressures in Hallux Valgus (HV), little is known about its clinical and radiological determinants. So, the aim of the present study was to determine the plantar pressure pattern in participants with mild HV, comparing to a control group, and their clinical and anthropometric determinants. Biofoot/IBV(®) in-shoe system was used to evaluate 79 participants with mild HV. Computerized measurements of the 1st intermetatarsal angle (IMA) and the hallux abductus angle (HAA) were made on antero-posterior radiographs. The clinical outcome was assessed using the AOFAS score. The dependent baropodometric variables and the independent clinical and anthropometric variables were subjected to a multiple regression analysis. In both groups, the highest average pressure was in the 2nd metatarsal head (MTH). The mean pressure under the Hallux was significantly higher in HV group (controls, 146.5±92.5kPa; HV, 328.5±113.2kPa; p<0.001). An 18.6% of average pressure under the 1st MTH was accounted for pain, first ray alignment and total AOFAS score. Variations of the HAA explained 26.8% of the mean Hallux pressure. Women with mild HV present with pathologically increased pressure under the Hallux, which is caused by the altered alignment of the first ray. Pain and clinical result were associated with the pressure under the 1st MTH and the remaining variables were only moderate predictors of dynamic plantar pressures. Copyright © 2010 Elsevier B.V. All rights reserved.

Preliminary tests of an advanced high-temperature combustion system

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

1983-01-01

A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

Parameter sensitivity analysis of a lumped-parameter model of a chain of lymphangions in series.

PubMed

Jamalian, Samira; Bertram, Christopher D; Richardson, William J; Moore, James E

2013-12-01

Any disruption of the lymphatic system due to trauma or injury can lead to edema. There is no effective cure for lymphedema, partly because predictive knowledge of lymphatic system reactions to interventions is lacking. A well-developed model of the system could greatly improve our understanding of its function. Lymphangions, defined as the vessel segment between two valves, are the individual pumping units. Based on our previous lumped-parameter model of a chain of lymphangions, this study aimed to identify the parameters that affect the system output the most using a sensitivity analysis. The system was highly sensitive to minimum valve resistance, such that variations in this parameter caused an order-of-magnitude change in time-average flow rate for certain values of imposed pressure difference. Average flow rate doubled when contraction frequency was increased within its physiological range. Optimum lymphangion length was found to be some 13-14.5 diameters. A peak of time-average flow rate occurred when transmural pressure was such that the pressure-diameter loop for active contractions was centered near maximum passive vessel compliance. Increasing the number of lymphangions in the chain improved the pumping in the presence of larger adverse pressure differences. For a given pressure difference, the optimal number of lymphangions increased with the total vessel length. These results indicate that further experiments to estimate valve resistance more accurately are necessary. The existence of an optimal value of transmural pressure may provide additional guidelines for increasing pumping in areas affected by edema.

Tissue classification and segmentation of pressure injuries using convolutional neural networks.

PubMed

Zahia, Sofia; Sierra-Sosa, Daniel; Garcia-Zapirain, Begonya; Elmaghraby, Adel

2018-06-01

This paper presents a new approach for automatic tissue classification in pressure injuries. These wounds are localized skin damages which need frequent diagnosis and treatment. Therefore, a reliable and accurate systems for segmentation and tissue type identification are needed in order to achieve better treatment results. Our proposed system is based on a Convolutional Neural Network (CNN) devoted to performing optimized segmentation of the different tissue types present in pressure injuries (granulation, slough, and necrotic tissues). A preprocessing step removes the flash light and creates a set of 5x5 sub-images which are used as input for the CNN network. The network output will classify every sub-image of the validation set into one of the three classes studied. The metrics used to evaluate our approach show an overall average classification accuracy of 92.01%, an average total weighted Dice Similarity Coefficient of 91.38%, and an average precision per class of 97.31% for granulation tissue, 96.59% for necrotic tissue, and 77.90% for slough tissue. Our system has been proven to make recognition of complicated structures in biomedical images feasible. Copyright © 2018 Elsevier B.V. All rights reserved.

Numerical simulation of the compressible Orszag-Tang vortex. Interim report, June 1988-February 1989

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahlburg, R.B.; Picone, J.M.

Results of fully compressible, Fourier collocation, numerical simulations of the Orszag-Tang vortex system are presented. Initial conditions consist of a nonrandom, periodic field in which the magnetic and velocity fields contain X-points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure-field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average flow Mach number of the flow. In the numerical simulations, this initial Mach number is varied from 0.2 to 0.6. These values correspond to average plasma beta valuesmore » ranging from 30.0 to 3.3, respectively. Compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as mass density and nonsolenoidal flow field. These effects include (1) retardation of growth of correlation between the magnetic field and the velocity field, (2) emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible-flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.« less

AMERICAN AIR FILTER KINPACTOR 10 X 56 VENTURI SCRUBBER EVALUATION

EPA Science Inventory

The report gives results of an evaluation of an American Air Filter Kinpactor 10 x 56 venturi scrubber, operating on emissions from a large borax fusing furnace. Average total efficiency was 97.5% during the test period. The venturi was operated at a pressure drop of 110 cm W. C....

21 CFR 172.260 - Oxidized polyethylene.

Code of Federal Regulations, 2014 CFR

2014-04-01

... ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Coatings, Films and Related Substances... average molecular weight of 1,200, as determined by high temperature vapor pressure osmometry; contains a maximum of 5 percent by weight of total oxygen; and has an acid value of 9 to 19. (b) The additive is used...

40 CFR 60.266 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... effluent gas from exhaust stream “i”, dscm/hr (dscf/hr). P=average furnace power input, MW. K=conversion....8, the owner or operator shall not allow gaseous diluents to be added to the effluent gas stream after the fabric in an open pressurized fabric filter collector unless the total gas volume flow from...

Comparative climatology of four marine stratocumulus regimes

NASA Technical Reports Server (NTRS)

Hanson, Howard P.

1990-01-01

The climatology of marine stratocumulus (MSc) cloud regimes off the west coasts of California, Peru, Morocco, and Angola are examined. Long-term, annual averages are presented for several quantities of interest in the four MSc regimes. The climatologies were constructed using the Comprehensive Ocean-Atmosphere Data Set (COADS). A 40 year time series of observations was extracted for 32 x 32 deg analysis domains. The data were taken from the monthly-averaged, 2 deg product. The resolution of the analysis is therefore limited to scales of greater than 200 km with submonthly variability not resolved. The averages of total cloud cover, sea surface temperature, and surface pressure are presented.

Stiffness and relaxation components of the exponential and logistic time constants may be used to derive a load-independent index of isovolumic pressure decay.

PubMed

Shmuylovich, Leonid; Kovács, Sándor J

2008-12-01

In current practice, empirical parameters such as the monoexponential time constant tau or the logistic model time constant tauL are used to quantitate isovolumic relaxation. Previous work indicates that tau and tauL are load dependent. A load-independent index of isovolumic pressure decline (LIIIVPD) does not exist. In this study, we derive and validate a LIIIVPD. Recently, we have derived and validated a kinematic model of isovolumic pressure decay (IVPD), where IVPD is accurately predicted by the solution to an equation of motion parameterized by stiffness (Ek), relaxation (tauc), and pressure asymptote (Pinfinity) parameters. In this study, we use this kinematic model to predict, derive, and validate the load-independent index MLIIIVPD. We predict that the plot of lumped recoil effects [Ek.(P*max-Pinfinity)] versus resistance effects [tauc.(dP/dtmin)], defined by a set of load-varying IVPD contours, where P*max is maximum pressure and dP/dtmin is the minimum first derivative of pressure, yields a linear relation with a constant (i.e., load independent) slope MLIIIVPD. To validate the load independence, we analyzed an average of 107 IVPD contours in 25 subjects (2,669 beats total) undergoing diagnostic catheterization. For the group as a whole, we found the Ek.(P*max-Pinfinity) versus tauc.(dP/dtmin) relation to be highly linear, with the average slope MLIIIVPD=1.107+/-0.044 and the average r2=0.993+/-0.006. For all subjects, MLIIIVPD was found to be linearly correlated to the subject averaged tau (r2=0.65), tauL(r2=0.50), and dP/dtmin (r2=0.63), as well as to ejection fraction (r2=0.52). We conclude that MLIIIVPD is a LIIIVPD because it is load independent and correlates with conventional IVPD parameters. Further validation of MLIIIVPD in selected pathophysiological settings is warranted.

Management of leg and pressure ulcer in hospitalized patients: direct costs are lower than expected.

PubMed

Assadian, Ojan; Oswald, Joseph S; Leisten, Rainer; Hinz, Peter; Daeschlein, Georg; Kramer, Axel

2011-01-01

In Germany, cost calculations on the financial burden of wound treatment are scarce. Studies for attributable costs in hospitalized patients estimate for pressure ulcer additional costs of € 6,135.50 per patient, a calculation based on the assumption that pressure ulcers will lead to prolonged hospitalization averaging 2 months. The scant data available in this field prompted us to conduct a prospective economical study assessing the direct costs of treatment of chronic ulcers in hospitalized patients. The study was designed and conducted as an observational, prospective, multi-centre economical study over a period of 8 months in three community hospitals in Germany. Direct treatment costs for leg ulcer (n=77) and pressure ulcer (n=35) were determined observing 67 patients (average age: 75±12 years). 109 treatments representing 111 in-ward admissions and 62 outpatient visits were observed. During a total of 3,331 hospitalized and 867 outpatient wound therapies, 4,198 wound dressing changes were documented. Costs of material were calculated on a per item base. Direct costs of care and treatment, including materials used, surgical interventions, and personnel costs were determined. An average of € 1,342 per patient (€ 48/d) was spent for treatment of leg ulcer (staff costs € 581, consumables € 458, surgical procedures € 189, and diagnostic procedures € 114). On average, each wound dressing change caused additional costs of € 15. For pressure ulcer, € 991 per patient (€ 52/d) was spent on average (staff costs € 313, consumables € 618, and for surgical procedures € 60). Each wound dressing change resulted in additional costs of € 20 on average. When direct costs of chronic wounds are calculated on a prospective case-by-case basis for a treatment period over 3 months, these costs are lower than estimated to date. While reduction in prevalence of chronic wounds along with optimised patient care will result in substantial cost saving, this saving might be lower than expected. Our results, however, do not serve as basis for making any conclusions on cost-benefit analysis for both, the affected individual, as well as for the society.

Changes of contact pressure and area in patellofemoral joint after different meniscectomies.

PubMed

Bai, Bo; Shun, Hui; Yin, Zhi Xun; Liao, Zhuang-Wen; Chen, Ni

2012-05-01

We investigated the contact pressure and area of the patellofemoral joint both before and after different meniscectomies to provide a biomechanical basis for selecting meniscectomy and its clinical application for meniscus injuries. Six fresh cadaveric knees were used in the study. Using Staubli robots and an ultra-low-min-type pressure-sensitive tablet, changes in contact area and stress in the patellofemoral joint were measured at various flexion angles following different parts and degrees of meniscectomy. The patellofemoral contact area enlarged with the increase of knee flexion angle. From the values obtained from contact areas and average contact pressure of the patellofemoral joint, we found no significant difference between partial meniscectomy and intact knees, but a significant difference was found between total meniscectomy and intact knees. The contact area after lateral meniscectomy was statistically less than that of intact knees. The mean patellofemoral contact pressure after lateral meniscectomy was larger than in intact knees at each angle of flexion. No significant difference in contact area was observed between intact knees and medial meniscectomy. The average patellofemoral contact pressure after medial meniscectomy was larger than in intact knees from 0° ~ 30° of knee flexion, and no significant differences were found between intact knees and medial meniscectomy while knee bending from 60° to 90°. Different meniscectomies result in high contact pressure or disordered distribution of contact pressure, which may be the cause of postoperative patellofemoral degenerative arthrosis.

Skin-Friction Measurements in Incompressible Flow

NASA Technical Reports Server (NTRS)

Smith, Donald W.; Walker, John H.

1959-01-01

Experiments have been conducted to measure the local surface-shear stress and the average skin-friction coefficient in Incompressible flow for a turbulent boundary layer on a smooth flat plate having zero pressure gradient. Data were obtained for a range of Reynolds numbers from 1 million to 45 million. The local surface-shear stress was measured by a floating-element skin-friction balance and also by a calibrated total head tube located on the surface of the test wall. The average skin-friction coefficient was obtained from boundary-layer velocity profiles.

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2014 CFR

2014-07-01

... fitted for the test kW PB Total barometric pressure (average of the pre-test and post-test values) kPa...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions Pt. 91, Subpt... Term Unit AYM Final weighted emission test results g/kW-hr C3 H8 Propane CB Concentration of emission...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2010 CFR

2010-07-01

... fitted for the test kW PB Total barometric pressure (average of the pre-test and post-test values) kPa...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions Pt. 91, Subpt... Term Unit AYM Final weighted emission test results g/kW-hr C3 H8 Propane CB Concentration of emission...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2012 CFR

2012-07-01

... fitted for the test kW PB Total barometric pressure (average of the pre-test and post-test values) kPa...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions Pt. 91, Subpt... Term Unit AYM Final weighted emission test results g/kW-hr C3 H8 Propane CB Concentration of emission...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2011 CFR

2011-07-01

... fitted for the test kW PB Total barometric pressure (average of the pre-test and post-test values) kPa...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions Pt. 91, Subpt... Term Unit AYM Final weighted emission test results g/kW-hr C3 H8 Propane CB Concentration of emission...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2013 CFR

2013-07-01

... fitted for the test kW PB Total barometric pressure (average of the pre-test and post-test values) kPa...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions Pt. 91, Subpt... Term Unit AYM Final weighted emission test results g/kW-hr C3 H8 Propane CB Concentration of emission...

A prospective double-blinded randomized controlled trial comparing systemic stress response in Laparoascopic cholecystectomy between low-pressure and standard-pressure pneumoperitoneum.

PubMed

Shoar, Saeed; Naderan, Mohammad; Ebrahimpour, Hossein; Soroush, Ahmadreza; Nasiri, Shirzad; Movafegh, Ali; Khorgami, Zhamak

2016-04-01

Laparoscopic cholecystectomy (LC) has become the gold-standard treatment for gallstone diseases. However, despite huge reduction in operative injury, systemic stress response remains high. This randomized controlled trial (RCT) aimed to compare systemic stress response between 2 different techniques of CO2 pneumoperitoneum. Trough a prospective, double-blinded RCT, serum levels of cortisol, adrenaline, glucose, and C-reactive protein (CRP) were compared between the two groups consisted of 50 patients undergoing LC under low-pressure and standard-pressure CO2 pneimoperitoneum. A total of fifty patients undergoing LC were equally assigned to 2 groups of twenty five patients. Average age was 48 ± 13.8 years (range, 19-74 years). Operative time was similar between standard-pressure group (47.8 ± 16.8 min) and low-pressure group (53.6 ± 25.1). Moreover, intra-operative IV volume administration and urine output did not differ significantly between the 2 groups (p > 0.05). Although the average heart rate and mean arterial pressure were slightly higher in a standard-pressure group compared with a low-pressure group, serial measurements of these parameters were statistically similar between the 2 groups. Serial changes of serum levels of cortisol, glucose, adrenaline, and CRP were compared between surgery day, postoperative 6-h and 1st postoperative day, which did not differ significantly between the standard-pressure and the low-pressure groups (p > 0.05). Our study did not reveal any alteration in systemic stress response with reduction in intra-abdominal pressure of pneumoperitoneum in LC. RCT REGISTRATION: irct.ir ID: IRCT201110072982N5. Copyright © 2016 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

Axial-Flow Turbine Rotor Discharge-Flow Overexpansion and Limit-Loading Condition, Part I: Computational Fluid Dynamics (CFD) Investigation

NASA Technical Reports Server (NTRS)

Chen, Shu-Cheng S.

2017-01-01

A Computational Fluid Dynamic (CFD) investigation is conducted over a two-dimensional axial-flow turbine rotor blade row to study the phenomena of turbine rotor discharge flow overexpansion at subcritical, critical, and supercritical conditions. Quantitative data of the mean-flow Mach numbers, mean-flow angles, the tangential blade pressure forces, the mean-flow mass flux, and the flow-path total pressure loss coefficients, averaged or integrated across the two-dimensional computational domain encompassing two blade-passages, are obtained over a series of 14 inlet-total to exit-static pressure ratios, from 1.5 (un-choked; subcritical condition) to 10.0 (supercritical with excessively high pressure ratio.) Detailed flow features over the full domain-of-computation, such as the streamline patterns, Mach contours, pressure contours, blade surface pressure distributions, etc. are collected and displayed in this paper. A formal, quantitative definition of the limit loading condition based on the channel flow theory is proposed and explained. Contrary to the comments made in the historical works performed on this subject, about the deficiency of the theoretical methods applied in analyzing this phenomena, using modern CFD method for the study of this subject appears to be quite adequate and successful. This paper describes the CFD work and its findings.

Cardiovascular risk and blood pressure control in a Spanish hypertensive population attended in a Primary Care setting. Data from the PRESCAP 2006 study.

PubMed

Rodriguez-Roca, Gustavo C; Llisterri-Caro, Jose L; Barrios-Alonso, Vivencio; Alonso-Moreno, Francisco J; Lou-Arnal, Salvador; Prieto-Diaz, Miguel A; Sanchez-Ruiz, Tomas; Dura-Belinchon, Rafael; Santos-Rodriguez, Jose A; Divison-Garrote, Juan A; Gonzalez-Segura, Diego; Banegas-Banegas, Jose R

2009-01-01

To analyse the cardiovascular risk of a broad sample of hypertensive patients and to examine whether there are differences in blood pressure control and associated factors according to the different cardiovascular risk categories. A total of 10,520 patients > or = 18 years old were included (mean age 64.6+/-11.3 years; 53.7% women). In this cohort, 3.3% were average risk, 22.6% low added risk, 22.2% moderate added risk, 33.5% high added risk and 18.4% very high added risk. Blood pressure was controlled in 41.4% (95% CI 40.5-42.4) of the total population, in 91.7% of patients with low added risk, in 19.4% with moderate added risk, in 27.4% with high added risk and in 6.8% with very high added risk. Diabetes was the factor most strongly associated with poor blood pressure control in patients with high to very high added risk (OR=7.2; p<0.0001). More than half of the hypertensive patients treated in primary health care have a high or very high added cardiovascular risk. In these patients, blood pressure control is inadequate and diabetes is associated with a sevenfold increase in the likelihood of poor blood pressure control.

The effect of continuous positive airway pressure on middle ear pressure.

PubMed

Lin, Fred Y; Gurgel, Richard K; Popelka, Gerald R; Capasso, Robson

2012-03-01

While continuous positive airway pressure (CPAP) is commonly used for obstructive sleep apnea treatment, its effect on middle ear pressure is unknown. The purpose of this study was to measure the effect of CPAP on middle ear pressure and describe the correlation between CPAP levels and middle ear pressures. Retrospective review of normal tympanometry values and a prospective cohort evaluation of subjects' tympanometric values while using CPAP at distinct pressure levels. A total of 3,066 tympanograms were evaluated to determine the normal range of middle ear pressures. Ten subjects with no known history of eustachian tube dysfunction or obstructive sleep apnea had standard tympanometry measurements while wearing a CPAP device. Measurements were taken at baseline and with CPAP air pressures of 0, 5, 10, and 15 cm H(2)O. The percentage of normal control patients with middle ear pressures above 40 daPa was 0.03%. In the study population, prior to a swallowing maneuver to open the eustachian tube, average middle ear pressures were 21.67 daPa, 22.63 daPa, 20.42, daPa, and 21.58 daPa with CPAP pressures of 0, 5, 10, and 15 cm H(2) 0, respectively. After swallowing, average middle ear air pressures were 18.83 daPa, 46.75 daPa, 82.17 daPa, and 129.17 daPa with CPAP pressures of 0, 5, 10, and 15 cm H(2)0, respectively. The postswallow Pearson correlation coefficient correlating CPAP and middle ear pressures was 0.783 (P < 0.001). Middle ear air pressure is directly proportional to CPAP air pressure in subjects with normal eustachian tube function. Middle ear pressure reaches supraphysiologic levels at even minimal CPAP levels. Although further investigation is necessary, there may be otologic implications for patients who are chronically CPAP dependent. These findings may also influence the perioperative practice of otologic and skull base surgeons. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

[Influence of weather in the incidence of acute myocardial infarction in Galicia (Spain)].

PubMed

Fernández-García, José Manuel; Dosil Díaz, Olga; Taboada Hidalgo, Juan José; Fernández, José Ramón; Sánchez-Santos, Luis

2015-08-07

To assess the interactions between weather and the impact of each individual meteorological parameters in the incidence of acute myocardial infarctions (AMI) in Galicia. Retrospective study analyzing the number of AMI diagnosed and transferred to the hospital by the Emergencies Sanitary System of Galicia between 2002 and 2009. We included patients with clinical and ECG findings of AMI. The correlation between 10-minute meteorological variables (temperature, humidity, pressure, accumulated rainfall and wind speed) recorded by MeteoGalicia and the incidence of AMI was assessed. A total of 4,717 AMI were registered (72.8% men, 27.2% women). No seasonal variations were found. No significant correlations were detected with regard to average daily temperature (P=.683) or wind speed (P=.895). Correlation between atmospheric pressure and incidence of AMI was significant (P<.005), as well as with the daily relative humidity average (P=.005). Our study showed a statistical significant association with atmospheric pressure and with the daily relative humidity average. Since the local conditions of weather are widely variable, future studies should establish the relationship between weather patterns (including combinations of meteorological parameters), rather than seasonal variations, and the incidence of AMI. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Fluctuating pressures measured beneath a high-temperature, turbulent boundary layer on a flat plate at Mach number of 5

NASA Technical Reports Server (NTRS)

Parrott, Tony L.; Jones, Michael G.; Albertson, Cindy W.

1989-01-01

Fluctuating pressures were measured beneath a Mach 5, turbulent boundary layer on a flat plate with an array of piezoresistive sensors. The data were obtained with a digital signal acquisition system during a test run of 4 seconds. Data sampling rate was such that frequency analysis up to 62.5 kHz could be performed. To assess in situ frequency response of the sensors, a specially designed waveguide calibration system was employed to measure transfer functions of all sensors and related instrumentation. Pressure time histories were approximated well by a Gaussian prohibiting distribution. Pressure spectra were very repeatable over the array span of 76 mm. Total rms pressures ranged from 0.0017 to 0.0046 of the freestream dynamic pressure. Streamwise, space-time correlations exhibited expected decaying behavior of a turbulence generated pressure field. Average convection speed was 0.87 of freestream velocity. The trendless behavior with sensor separation indicated possible systematic errors.

[Analysis of the characteristic of pharyngeal paraesthesia patients by high resolution manometry].

PubMed

Gu, Yun; Qian, Wei

2015-09-01

To discuss the pressure changing characteristics of upper esophageal sphincter (UES), lower esophageal sphincter (LES) and the esophagus kinetic characteristics of pharyngeal paraesthesia patients. To take high resolution manometry in 44 cases of pharyngeal paraesthesia patients and 23 normal subjects separately. According to the RSI score,the 44 patients were divided into group A (the group without reflux, RSI < 13, n = 25) and group B (the group with reflux, RSI ≥ 13, n = 19). The UES average resting pressure and average residual pressure of patients group were higher than the control group (P < 0.05); The UES average resting pressure and average residual pressure of group B were higher than group A (P < 0.05); The LES average resting pressure and average residual pressure of group B were lower than group A and the control group (P < 0.05); The comparison of LES average resting pressure and average residual pressure between group A and the control group was not statistically significant (P > 0.05). The esophagus DCI of group B was lower than that of group A and control group (P < 0.05). The esophagus DCI comparison between group A and control group was not statistically significant (P > 0.05). The pharyngeal paresthesia symptoms of'patients was associated with the increasing of UES pressure. The pharyngeal paresthesia symptoms of group with reflux was related to low pressure of LES and high pressure of UES. The last part of esophagus of group with reflux had obstacles in powers, which weaken the peristalsis and declined the ability to clear the bolus and gastric reflux material.

The local phase transitions of the solvent in the neighborhood of a solvophobic polymer at high pressures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Budkov, Yu. A., E-mail: urabudkov@rambler.ru; National Research University Higher School of Economics, Moscow; Department of Chemistry, Lomonosov Moscow State University, Moscow

2014-11-28

We investigate local phase transitions of the solvent in the neighborhood of a solvophobic polymer chain which is induced by a change of the polymer-solvent repulsion and the solvent pressure in the bulk solution. We describe the polymer in solution by the Edwards model, where the conditional partition function of the polymer chain at a fixed radius of gyration is described by a mean-field theory. The contributions of the polymer-solvent and the solvent-solvent interactions to the total free energy are described within the mean-field approximation. We obtain the total free energy of the solution as a function of the radiusmore » of gyration and the average solvent number density within the gyration volume. The resulting system of coupled equations is solved varying the polymer-solvent repulsion strength at high solvent pressure in the bulk. We show that the coil-globule (globule-coil) transition occurs accompanied by a local solvent evaporation (condensation) within the gyration volume.« less

A general low frequency acoustic radiation capability for NASTRAN

NASA Technical Reports Server (NTRS)

Everstine, G. C.; Henderson, F. M.; Schroeder, E. A.; Lipman, R. R.

1986-01-01

A new capability called NASHUA is described for calculating the radiated acoustic sound pressure field exterior to a harmonically-excited arbitrary submerged 3-D elastic structure. The surface fluid pressures and velocities are first calculated by coupling a NASTRAN finite element model of the structure with a discretized form of the Helmholtz surface integral equation for the exterior fluid. After the fluid impedance is calculated, most of the required matrix operations are performed using the general matrix manipulation package (DMAP) available in NASTRAN. Far field radiated pressures are then calculated from the surface solution using the Helmholtz exterior integral equation. Other output quantities include the maximum sound pressure levels in each of the three coordinate planes, the rms and average surface pressures and normal velocities, the total radiated power and the radiation efficiency. The overall approach is illustrated and validated using known analytic solutions for submerged spherical shells subjected to both uniform and nonuniform applied loads.

Droplet squeezing through a narrow constriction: Minimum impulse and critical velocity

NASA Astrophysics Data System (ADS)

Zhang, Zhifeng; Drapaca, Corina; Chen, Xiaolin; Xu, Jie

2017-07-01

Models of a droplet passing through narrow constrictions have wide applications in science and engineering. In this paper, we report our findings on the minimum impulse (momentum change) of pushing a droplet through a narrow circular constriction. The existence of this minimum impulse is mathematically derived and numerically verified. The minimum impulse happens at a critical velocity when the time-averaged Young-Laplace pressure balances the total minor pressure loss in the constriction. Finally, numerical simulations are conducted to verify these concepts. These results could be relevant to problems of energy optimization and studies of chemical and biomedical systems.

Wake-shock interaction at a Mach number of 6

NASA Technical Reports Server (NTRS)

Walsh, M. J.

1978-01-01

Measurements of mean pitot pressure, static pressure, and total temperature were made in the two dimensional turbulent mixing region of a wake downstream of an interaction with a shock-expansion wave system. The results indicated that: (1) the shock increased the mixing, and (2) the expansion field that followed the shock decreased the turbulent mixing. The overall effect of the shock-expansion wave interaction was dependent on the orientation of the expansion wave with respect to the intersecting shock wave. These data could be used to validate nonequilibrium turbulence modeling and numerical solution of the time averaged Navier-Stokes equations.

Quantifying patterns of change in marine ecosystem response to multiple pressures.

PubMed

Large, Scott I; Fay, Gavin; Friedland, Kevin D; Link, Jason S

2015-01-01

The ability to understand and ultimately predict ecosystem response to multiple pressures is paramount to successfully implement ecosystem-based management. Thresholds shifts and nonlinear patterns in ecosystem responses can be used to determine reference points that identify levels of a pressure that may drastically alter ecosystem status, which can inform management action. However, quantifying ecosystem reference points has proven elusive due in large part to the multi-dimensional nature of both ecosystem pressures and ecosystem responses. We used ecological indicators, synthetic measures of ecosystem status and functioning, to enumerate important ecosystem attributes and to reduce the complexity of the Northeast Shelf Large Marine Ecosystem (NES LME). Random forests were used to quantify the importance of four environmental and four anthropogenic pressure variables to the value of ecological indicators, and to quantify shifts in aggregate ecological indicator response along pressure gradients. Anthropogenic pressure variables were critical defining features and were able to predict an average of 8-13% (up to 25-66% for individual ecological indicators) of the variation in ecological indicator values, whereas environmental pressures were able to predict an average of 1-5 % (up to 9-26% for individual ecological indicators) of ecological indicator variation. Each pressure variable predicted a different suite of ecological indicator's variation and the shapes of ecological indicator responses along pressure gradients were generally nonlinear. Threshold shifts in ecosystem response to exploitation, the most important pressure variable, occurred when commercial landings were 20 and 60% of total surveyed biomass. Although present, threshold shifts in ecosystem response to environmental pressures were much less important, which suggests that anthropogenic pressures have significantly altered the ecosystem structure and functioning of the NES LME. Gradient response curves provide ecologically informed transformations of pressure variables to explain patterns of ecosystem structure and functioning. By concurrently identifying thresholds for a suite of ecological indicator responses to multiple pressures, we demonstrate that ecosystem reference points can be evaluated and used to support ecosystem-based management.

Hemodynamic response to exercise and head-up tilt of patients implanted with a rotary blood pump: a computational modeling study.

PubMed

Lim, Einly; Salamonsen, Robert Francis; Mansouri, Mahdi; Gaddum, Nicholas; Mason, David Glen; Timms, Daniel L; Stevens, Michael Charles; Fraser, John; Akmeliawati, Rini; Lovell, Nigel Hamilton

2015-02-01

The present study investigates the response of implantable rotary blood pump (IRBP)-assisted patients to exercise and head-up tilt (HUT), as well as the effect of alterations in the model parameter values on this response, using validated numerical models. Furthermore, we comparatively evaluate the performance of a number of previously proposed physiologically responsive controllers, including constant speed, constant flow pulsatility index (PI), constant average pressure difference between the aorta and the left atrium, constant average differential pump pressure, constant ratio between mean pump flow and pump flow pulsatility (ratioP I or linear Starling-like control), as well as constant left atrial pressure ( P l a ¯ ) control, with regard to their ability to increase cardiac output during exercise while maintaining circulatory stability upon HUT. Although native cardiac output increases automatically during exercise, increasing pump speed was able to further improve total cardiac output and reduce elevated filling pressures. At the same time, reduced venous return associated with upright posture was not shown to induce left ventricular (LV) suction. Although P l a ¯ control outperformed other control modes in its ability to increase cardiac output during exercise, it caused a fall in the mean arterial pressure upon HUT, which may cause postural hypotension or patient discomfort. To the contrary, maintaining constant average pressure difference between the aorta and the left atrium demonstrated superior performance in both exercise and HUT scenarios. Due to their strong dependence on the pump operating point, PI and ratioPI control performed poorly during exercise and HUT. Our simulation results also highlighted the importance of the baroreflex mechanism in determining the response of the IRBP-assisted patients to exercise and postural changes, where desensitized reflex response attenuated the percentage increase in cardiac output during exercise and substantially reduced the arterial pressure upon HUT. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Piezoelectrically-induced trap-depth reduction model of elastico-mechanoluminescent materials

NASA Astrophysics Data System (ADS)

Chandra, B. P.; Chandra, V. K.; Jha, Piyush

2015-03-01

Considering the detrapping of charge carriers due to reduction in trap-depth caused by piezoelectric field produced by applied pressure, an expression is derived for the detrapping rate of electrons. Then, an expression is obtained for the rate of generation of excited ions produced during capture of detrapped electrons by Eu3+ ions in persistent luminescent materials or by the energy released during electron-hole recombination in ZnS:Mn crystals. Finally, an expression is explored for the elastico-mechanoluminescence (EML) intensity, which is able to explain satisfactorily the characteristics of EML for the application of static pressure as well as for impact pressure. The total number of detrapped electrons and the total EML intensity are found to increase linearly with the electrostatic energy of the crystals in piezoelectric field. It is shown that the EML intensity should increase with the EML efficiency, number of crystallites (volume of sample), concentration of local piezoelectric regions in crystallites, piezoelectric constant of local piezoelectric regions, average length of the local piezoelectric regions, total number of electron traps, pressing rate, and applied pressure, and it should be higher for the materials having low value of threshold pressure and low value of trap-depth in unstressed condition. On the basis of the piezoelectrically-induced trap-depth reduction model of EML reported in the present investigation novel intense elastico mechanoluminescent materials having repetitive EML with undiminished intensity for successive loadings can be tailored which may find applications in sensing, imaging, lighting, colored displays, and other mechano-optical devices.

Sensitive Procedures for Determining the Permeation Resistance of Chlorinated Polyethylene Against Liquid Propellants

NASA Technical Reports Server (NTRS)

Waller, Jess M.; Williams, James H.; Fries, Joseph (Technical Monitor)

1999-01-01

The permeation resistance of chlorinated polyethylene (CPE) used in totally encapsulating chemical protective suits against the aerospace fuels hydrazine, monomethylhydrazine, and uns-dimethylhydrazine was determined by measuring the breakthrough time (BT) and time-averaged vapor transmission rate (VTR) using procedures consistent with ASTM F 739 and ASTM F 1383. Two exposure scenarios were simulated: a 2 hour (h) fuel vapor exposure, and a liquid fuel "splash" followed by a 2 h vapor exposure. To simulate internal suit pressure during operation, a positive differential pressure of 0.3 in. water (75 Pa) on the collection side of the permeation apparatus was used. Using the available data, a model was developed to estimate propellant concentrations inside an air-line fed, totally encapsulating chemical protective suit. Concentrations were calculated under simulated conditions of fixed vapor transmission rate, variable breathing air flow rate, and variable splash exposure area. Calculations showed that the maximum allowable permeation rates of hydrazine fuels through CPE were of the order of 0.05 to 0.08 ng/sq cm min for encapsulating suits with low breathing air flow rates (of the order of 5 scfm or 140 L min-1). Above these permeation rates, the 10 parts-per-billion (ppb) threshold limit value time-weighted average could be exceeded. To evaluate suit performance at 10 ppb threshold-limiting value/time-weighted average level concentrations, use of a sensitive analytical method such as cation exchange high performance liquid chromatography with amperometric detection was found to be essential. The analytical detection limit determines the lowest measurable VTR, which in turn governed the lowest per meant concentration that could be calculated inside the totally encapsulating chemical protective suit.

An analysis of collegiate band directors' exposure to sound pressure levels

NASA Astrophysics Data System (ADS)

Roebuck, Nikole Moore

Noise-induced hearing loss (NIHL) is a significant but unfortunate common occupational hazard. The purpose of the current study was to measure the magnitude of sound pressure levels generated within a collegiate band room and determine if those sound pressure levels are of a magnitude that exceeds the policy standards and recommendations of the Occupational Safety and Health Administration (OSHA), and the National Institute of Occupational Safety and Health (NIOSH). In addition, reverberation times were measured and analyzed in order to determine the appropriateness of acoustical conditions for the band rehearsal environment. Sound pressure measurements were taken from the rehearsal of seven collegiate marching bands. Single sample t test were conducted to compare the sound pressure levels of all bands to the noise exposure standards of OSHA and NIOSH. Multiple regression analysis were conducted and analyzed in order to determine the effect of the band room's conditions on the sound pressure levels and reverberation times. Time weighted averages (TWA), noise percentage doses, and peak levels were also collected. The mean Leq for all band directors was 90.5 dBA. The total accumulated noise percentage dose for all band directors was 77.6% of the maximum allowable daily noise dose under the OSHA standard. The total calculated TWA for all band directors was 88.2% of the maximum allowable daily noise dose under the OSHA standard. The total accumulated noise percentage dose for all band directors was 152.1% of the maximum allowable daily noise dose under the NIOSH standards, and the total calculated TWA for all band directors was 93dBA of the maximum allowable daily noise dose under the NIOSH standard. Multiple regression analysis revealed that the room volume, the level of acoustical treatment and the mean room reverberation time predicted 80% of the variance in sound pressure levels in this study.

Analytical and experimental evaluation of a 3-D hypersonic fixed-geometry, swept, mixed compression inlet

NASA Technical Reports Server (NTRS)

Agnone, Anthony M.

1987-01-01

The performance of a fixed-geometry, swept, mixed compression hypersonic inlet is presented. The experimental evaluation was conducted for a Mach number of 6.0 and for several angles of attack. The measured surface pressures and pitot pressure surveys at the inlet throat are compared to computations using a three-dimensional Euler code and an integral boundary layer theory. Unique features of the intake design, including the boundary layer control, insure a high inlet performance. The experimental data show the inlet has a high mass averaged total pressure recovery, a high mass capture and nearly uniform flow diffusion. The swept inlet exhibits excellent starting characteristics, and high flow stability at angle of attack.

First-principles studies of PETN molecular crystal vibrational frequencies under high pressure

NASA Astrophysics Data System (ADS)

Perger, Warren; Zhao, Jijun

2005-07-01

The vibrational frequencies of the PETN molecular crystal were calculated using the first-principles CRYSTAL03 program which employs an all-electron LCAO approach and calculates analytic first derivatives of the total energy with respect to atomic displacements. Numerical second derivatives were used to enable calculation of the vibrational frequencies at ambient pressure and under various states of compression. Three different density functionals, B3LYP, PW91, and X3LYP were used to examine the effect of the exchange-correlation functional on the vibrational frequencies. The pressure-induced shift of the vibrational frequencies will be presented and compared with experiment. The average deviation with experimental results is shown to be on the order of 2-3%, depending on the functional used.

Preston Probe Calibrations at High Reynolds Number

NASA Technical Reports Server (NTRS)

Smits, Alexander J.

1998-01-01

The overall goal of the research effort is to study the performance of two Preston probes designed by NASA Langley Research Center across an unprecedented range of Reynolds number (based on friction velocity and probe diameter), and perform an accurate calibration over the same Reynolds number range. Using the Superpipe facility in Princeton, two rounds of experiments were performed. In each round of experiments for each Reynolds number, the pressure gradient, static pressure from the Preston probes and the total pressure from the Preston probes were measured. In the first round, 3 Preston probes having outer diameters of 0.058 inches, 0.083 inches and 0.203 inches were tested over a large range of pipe Reynolds numbers. Two data reduction methods were employed: first, the static pressure measured on the Preston probe was used to calculate P (modified Preston probe configuration), and secondly, the static pressure measured at the reference pressure tap was used to calculate P (un-modified Preston probe configuration). For both methods, the static pressure was adjusted to correspond with the static pressure at the Preston probe tip using the pressure gradient. The measurements for Preston probes with diameters of 0.058 inches, and 0.083 inches respectively were performed in the test pipe before it was polished a second time. Therefore, the measurements at high pipe Reynolds numbers may have been affected by roughness. In the second round of experiments the 0.058 inches and 0.083 inches diameter, un-modified probes were tested after the pipe was polished and prepared to ensure that the surface was smooth. The average velocity was estimated by assuming that the connection between the centerline velocity and the average velocity was known, and by using a Pitot tube to measure the centerline velocity. A preliminary error estimate suggests that it is possible to introduce a 1% to 2% error in estimating the average velocity using this approach. The evidence on the errors attending the second data set is somewhat circumstantial, and the measurements have not been repeated using a better approach, it seems probable that the correlation given applies to un-modified Preston probes over the range 6.4 less than x* less than 11.3.

Medial shoe-ground pressure and specific running injuries: A 1-year prospective cohort study.

PubMed

Brund, René B K; Rasmussen, Sten; Nielsen, Rasmus O; Kersting, Uwe G; Laessoe, Uffe; Voigt, Michael

2017-09-01

Achilles tendinitis, plantar fasciopathy and medial tibial stress syndrome injuries (APM-injuries) account for approximately 25% of the total number of running injuries amongst recreational runners. Reports on the association between static foot pronation and APM-injuries are contradictory. Possibly, dynamic measures of pronation may display a stronger relationship with the risk of APM-injuries. Therefore, the purpose of the present study was to investigate if running distance until the first APM-injury was dependent on the foot balance during stance phase in recreational male runners. Prospective cohort study. Foot balance for both feet was measured during treadmill running at the fastest possible 5000-m running pace in 79 healthy recreational male runners. Foot balance was calculated by dividing the average of medial pressure with the average of lateral pressure. Foot balance was categorized into those which presented a higher lateral shod pressure (LP) than medial pressure, and those which presented a higher medial shod pressure (MP) than lateral pressure during the stance phase. A time-to-event model was used to compare differences in incidence between foot balance groups. Compared with the LP-group (n=59), the proportion of APM-injuries was greater in the MP-group (n=99) after 1500km of running, resulting in a cumulative risk difference of 16%-points (95% CI=3%-point; 28%-point, p=0.011). Runners displaying a more medial pressure during stance phase at baseline sustained a greater amount of APM-injuries compared to those displaying a lateral shod pressure during stance phase. Prospective studies including a greater amount of runners are needed to confirm this relationship. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Unsteady specific work and isentropic efficiency of a radial turbine driven by pulsed detonations

NASA Astrophysics Data System (ADS)

Rouser, Kurt P.

There has been longstanding government and industry interest in pressure-gain combustion for use in Brayton cycle based engines. Theoretically, pressure-gain combustion allows heat addition with reduced entropy loss. The pulsed detonation combustor (PDC) is a device that can provide such pressure-gain combustion and possibly replace typical steady deflagration combustors. The PDC is inherently unsteady, however, and comparisons with conventional steady deflagration combustors must be based upon time-integrated performance variables. In this study, the radial turbine of a Garrett automotive turbocharger was coupled directly to and driven, full admission, by a PDC in experiments fueled by hydrogen or ethylene. Data included pulsed cycle time histories of turbine inlet and exit temperature, pressure, velocity, mass flow, and enthalpy. The unsteady inlet flowfield showed momentary reverse flow, and thus unsteady accumulation and expulsion of mass and enthalpy within the device. The coupled turbine-driven compressor provided a time-resolved measure of turbine power. Peak power increased with PDC fill fraction, and duty cycle increased with PDC frequency. Cycle-averaged unsteady specific work increased with fill fraction and frequency. An unsteady turbine efficiency formulation is proposed, including heat transfer effects, enthalpy flux-weighted total pressure ratio, and ensemble averaging over multiple cycles. Turbine efficiency increased with frequency but was lower than the manufacturer reported conventional steady turbine efficiency.

Comparison between SAGE II and ISCCP high-level clouds. 2: Locating clouds tops

NASA Technical Reports Server (NTRS)

Liao, Xiaohan; Rossow, William B.; Rind, David

1995-01-01

A comparison is made of the vertical distribution of high-level cloud tops derived from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation measurements and from the International Satellite Cloud Climatology Project (ISCCP) for all Julys and Januarys in 1985 to 1990. The results suggest that ISCCP overestimates the pressure of high-level clouds by up to 50-150 mbar, particularly at low latitudes. This is caused by the frequent presence of clouds with diffuse tops (greater than 50% time when cloudy events are observed). The averaged vertical extent of the diffuse top is about 1.5 km. At midlatitudes where the SAGE II and ISCCP cloud top pressure agree best, clouds with distinct tops reach a maximum relative proportion of the total level cloud amount (about 30-40%), and diffuse-topped clouds are reduced to their minimum (30-40%). The ISCCP-defined cloud top pressure should be regarded not as the material physical height of the clouds but as the level which emits the same infrared radiance as observed. SAGE II and ISCCP cloud top pressures agree for clouds with distinct tops. There is also an indication that the cloud top pressures of optically thin clouds not overlying thicker clouds are poorly estimated by ISCCP at middle latitudes. The average vertical extent of these thin clouds is about 2.5 km.

Unsteady Flow Field in a Multistage Axial Flow Compressor

NASA Technical Reports Server (NTRS)

Suryavamshi, N.; Lakshminarayana, B.; Prato, J.

1997-01-01

The flow field in a multistage compressor is three-dimensional, unsteady, and turbulent with substantial viscous effects. Some of the specific phenomena that has eluded designers include the effects of rotor-stator and rotor-rotor interactions and the physics of mixing of velocity, pressure, temperature and velocity fields. An attempt was made, to resolve experimentally, the unsteady pressure and temperature fields downstream of the second stator of a multistage axial flow compressor which will provide information on rotor-stator interaction effects and the nature of the unsteadiness in an embedded stator of a three stage axial flow compressor. Detailed area traverse measurements using pneumatic five hole probe, thermocouple probe, semi-conductor total pressure probe (Kulite) and an aspirating probe downstream of the second stator were conducted at the peak efficiency operating condition. The unsteady data was then reduced through an ensemble averaging technique which splits the signal into deterministic and unresolved components. Auto and cross correlation techniques were used to correlate the deterministic total temperature and velocity components (acquired using a slanted hot-film probe at the same measurement locations) and the gradients, distributions and relative weights of each of the terms of the average passage equation were then determined. Based on these measurements it was observed that the stator wakes, hub leakage flow region, casing endwall suction surface corner region, and the casing endwall region away from the blade surfaces were the regions of highest losses in total pressure, lowest efficiency and highest levels of unresolved unsteadiness. The deterministic unsteadiness was found to be high in the hub and casing endwall regions as well as on the pressure side of the stator wake. The spectral distribution of hot-wire and kulite voltages shows that at least eight harmonics of all three rotor blade passing frequencies are present at this measurement location. In addition to the basic three rotor blade passing frequencies (R1, R2 and R3) and their harmonics, various difference frequencies such as (2R1 -R2) and (2R3-R2) and their harmonics are also observed. These difference frequencies are due to viscous and potential interactions between rotors 1, 2 and 3 which are sensed by both the total pressure and aspirating probes at this location. Significant changes occur to the stator exit flow features with passage of the rotor upstream of the stator. Because of higher convection speeds of the rotor wake on the suction surface of the downstream stator than on the pressure side, the chopped rotor wake was found to be arriving at different times on either side of the stator wake. As the rotor passes across the stator.

Validation of the Pangao PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Zhao, Hairong; Qiao, Weichang; Zhang, Rui; Cui, Peng; Hou, Fanglin; Zhang, Wenli

2018-02-01

The aim of this study was to validate the PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010 and the British Hypertension Society (BHS) protocols. A total of 33 participants were initially included on the basis of the ESH-IP, followed by examination of 85 participants according to the BHS protocol. The procedures and analysis methods of the protocols were followed precisely with left arm/wrist sequential measurements by two trained observers using a mercury sphygmomanometer and one supervisor using the device. The device passed the ESH-IP with an average difference of 1.45±6.46 mmHg for systolic blood pressure and 1.25±5.10 mmHg for diastolic blood pressure. Furthermore, the A/A grade of the BHS protocol was achieved with an average difference of 1.84±6.94 mmHg for systolic blood pressure and 1.15±6.49 mmHg for diastolic blood pressure, and thus, the device also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The Pangao PG-800A36 passed the requirements of the ESH-IP revision 2010 and achieved the A/A grade of the BHS protocol, which can be recommended for self-measurement in the general population.

Differences in prevalence of diastolic arterial hypertension in 1423 young individuals in two different interviews.

PubMed

De Lena, S M; Gende, O A; Almirón, M A; Cingolani, H E

1994-09-01

To determine prevalence of diastolic arterial hypertension (DAH) in young individuals using different criteria. Secondly, to test the possible different blood pressure reactions to mental stress and hand grip in two groups: group A, a 'low blood pressure group', and group B, diastolic blood pressure 90 mmHg or greater in one interview and below these values in a second interview. A total of 1423 volunteer medical students was recruited at La Plata School of Medicine, average age 21 +/- 3 years. Systolic and diastolic blood pressure were measured three times on two different occasions separated by one week. With the values obtained, prevalence of arterial hypertension was determined according to the criteria suggested by The Joint National Committee 4 (JNC-4) and the World Health Organization (WHO), and to statistical bases. Mental stress and hand grip tests were performed by groups A and B. The prevalence of DAH when only the first determination of the first interview was considered was 14.7%, 6.7% (considering the WHO criterion) or 5% (using the statistical criterion). These values are reduced if repeated measurements are averaged. The greatest reduction was obtained when the JNC-4 criterion was used (1.6%). The reactivity of stressors did not show any relationship with the initial blood pressure of the subjects. In epidemiological studies, the differences among the criteria should be considered when analyzing blood pressure of populations. Stress tests (mental stress and hand grip) do not help in identifying differences between the groups studied.

Measuring static seated pressure distributions and risk for skin pressure ulceration in ice sledge hockey players.

PubMed

Darrah, Shaun D; Dicianno, Brad E; Berthold, Justin; McCoy, Andrew; Haas, Matthew; Cooper, Rory A

2016-01-01

To determine whether sledge hockey players with physical disability have higher average seated pressures compared to non-disabled controls. Fifteen age-matched controls without physical disability and 15 experimental participants with physical disability were studied using a pressure mapping device to determine risk for skin pressure ulceration and the impact of cushioning and knee angle positioning on seated pressure distributions. Regardless of participant group, cushioning, or knee angle, average seated pressures exceeded clinically acceptable seated pressures. Controls had significantly higher average seated pressures than the disability group when knees were flexed, both with the cushion (p = 0.013) and without (p = 0.015). Knee extension showed significantly lower average pressures in controls, both with the cushion (p < 0.001) and without (p < 0.001). Placement of the cushion resulted in significantly lower average pressure in controls when knees were extended (p = 0.024) but not when flexed (p = 0.248). Placement of the cushion resulted in no difference in pressure (p = 0.443) in the disability group. Pressures recorded indicate high risk for skin ulceration. Cushioning was effective only in the control group with knees extended. That knee extension significantly lowered average seated pressures is important, as many sledge hockey players utilize positioning with larger knee flexion angles. Implications for Rehabilitation Ice sledge hockey is a fast growing adaptive sport. Adaptive sports have been associated with several positive improvements in overall health and quality of life, though may be putting players at risk for skin ulceration. Measured static seated pressure in sledges greatly exceeds current clinically accepted clinical guidelines. With modern improvements in wheelchair pressure relief/cushioning there are potential methods for improvement of elevated seated pressure in ice hockey sledges.

Sea level static calibration of a compact multimission aircraft propulsion simulator with inlet flow distortion

NASA Technical Reports Server (NTRS)

Won, Mark J.

1990-01-01

Wind tunnel tests of propulsion-integrated aircraft models have identified inlet flow distortion as a major source of compressor airflow measurement error in turbine-powered propulsion simulators. Consequently, two Compact Multimission Aircraft Propulsion Simulator (CMAPS) units were statically tested at sea level ambient conditions to establish simulator operating performance characteristics and to calibrate the compressor airflow against an accurate bellmouth flowmeter in the presence of inlet flow distortions. The distortions were generated using various-shaped wire mesh screens placed upstream of the compressor. CMAPS operating maps and performance envelopes were obtained for inlet total pressure distortions (ratio of the difference between the maximum and minimum total pressures to the average total pressure) up to 35 percent, and were compared to baseline simulator operating characteristics for a uniform inlet. Deviations from CMAPS baseline performance were attributed to the coupled variation of both compressor inlet-flow distortion and Reynolds number index throughout the simulator operating envelope for each screen configuration. Four independent methods were used to determine CMAPS compressor airflow; direct compressor inlet and discharge measurements, an entering/exiting flow-balance relationships, and a correlation between the mixer pressure and the corrected compressor airflow. Of the four methods, the last yielded the least scatter in the compressor flow coefficient, approximately + or - 3 percent over the range of flow distortions.

The effectiveness of intensive nursing care on seasonal variation of blood pressure in patients on peritoneal dialysis.

PubMed

Quan, Lei; Dong, Jie; Li, Yanjun; Zuo, Li

2012-06-01

  This article is a report of a study to reduce the seasonal variation of blood pressure in patients on peritoneal dialysis through an intensive programme of nursing care.   The seasonal variation of blood pressure is a common phenomenon in patients on maintenance dialysis. Whether or not this variation can be reduced through a given intervention is unknown.   The programme of intensive nursing care including education on volume control, home blood pressure monitoring and intensified antihypertensive treatment, was implemented from December 2006. The blood pressure, fluid and sodium removal and defined daily doses of antihypertensive agents were measured at 1-monthly intervals and averagely quarterly for seasonal values for spring, summer, autumn and winter, respectively, before (December 2005-November 2006) and after intervention (December 2006-November 2007).   A total of 76 clinically stable patients on peritoneal dialysis were enrolled and finally analysed. The mean age was 60·6 years, and dialysis duration was 23·2 months. Before intervention, there were important seasonal variations in systolic and diastolic blood pressure. After intensive nursing care was implemented, the seasonal variation of systolic blood pressure disappeared. The diastolic blood pressure still represented a season pattern, but the discrepancy between winter and summer decreased. There were no seasonal patterns of total fluid and sodium removal before and after intervention.   Intensive nursing care reduced the seasonal variation of blood pressure in patients on peritoneal dialysis. These data provided an evidence for implementing nurse-centred interventions in this population. © 2011 Blackwell Publishing Ltd.

Noninvasive laser coagulation of the canine vas deferens, in vivo

NASA Astrophysics Data System (ADS)

Cilip, Christopher M.; Ross, Ashley E.; Jarow, Jonathan P.; Fried, Nathaniel M.

2010-02-01

Development of a noninvasive vasectomy technique may eliminate male fear of complications (incision, bleeding, infection, and scrotal pain) and result in a more popular procedure. This study builds upon previously reported ex vivo tissue studies by exploring acute and short-term chronic in vivo canine studies. Isolation of the canine vas was achieved using a conventional vas ring clamp method. No perforation of the scrotal skin was necessary to occlude the vas. Laser radiation with a wavelength of 1075 nm, average power of 11.2 W, 500-ms pulse duration, 0.5 Hz pulse rate, and 3-mm-diameter spot was synchronized with cryogen spray cooling of the scrotal skin surface in a total of 8 dogs (n = 16 vasa) for a treatment time of 60 s. Burst pressure measurements were conducted at Days 0 and 21 (n = 8 vasa each day) to quantify the strength of vas closure. The vas was successfully thermally occluded in 15/16 (94%) procedures with 14/15 (93%) vas recording burst pressures above ejaculation pressure. One vas was not present, and another vas recorded a bursting pressure below ejaculation pressure. The coagulated vas bursting pressure averaged 283 +/- 34 mm Hg at Day 0 and 260 +/- 77 mm Hg at Day 21, significantly higher than reported vas ejaculation pressures of 136 +/- 29 mm Hg. Minor scrotal skin burns were observed during the recovery period. Noninvasive thermal occlusion of the vas is feasible in an in vivo canine model. Elimination of minor skin burns and longer term chronic in vivo canine studies are needed to confirm azospermia after vas occlusion without recanalization.

Pressure and heat-transfer distributions in a simulated wing-elevon cove with variable leakage at a free-stream Mach number of 6.9

NASA Technical Reports Server (NTRS)

Deveikis, W. D.; Bartlett, W.

1978-01-01

An experimental aerodynamic heating investigation was conducted to determine effects of hot boundary-layer ingestion into the cove on the windward surface between a wing and elevon for cove seal leak areas nominally between 0 and 100 percent of cove entrance area. Pressure and heating-rate distributions were obtained on the wing and elevon surfaces and on the cove walls of a full-scale model that represented a section of the cove region on the space shuttle orbiter. Data were obtained for both attached and separated turbulent boundary layers upstream of the unswept cove entrance. Average free-stream Mach number was 6.9, average free-stream unit Reynolds numbers were 1.31 x 10 to the 6th power and 4.40 x 10 to the 6th power per meter (0.40 x 10 to the 6th power and 1.34 x 10 to the 6th power per foot), and average total temperature was 1888 K (3400 R). Cove pressures and heating rates varied as a function of seal leak area independent of leak aspect ratio. Although cove heating rates for attached flow did not appear intolerable, it was postulated that convective heating in the cove may increase with time. For separated flow, the cove environment was considered too severe for unprotected interior structures of control surfaces.

40 CFR Table 5 to Subpart Jjjjj of... - Continuous Compliance With Emission Limits and Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... kilns equipped with WS i. Collecting the scrubber pressure drop data according to § 63.8450(a); reducing the scrubber pressure drop data to 3-hour block averages according to § 63.8450(a); maintaining the average scrubber pressure drop for each 3-hour block period at or above the average pressure drop...

Average rainwater pH, concepts of atmospheric acidity, and buffering in open systems

NASA Astrophysics Data System (ADS)

Liljestrand, Howard M.

The system of water equilibrated with a constant partial pressure of CO 2, as a reference point for pH acidity-alkalinity relationships, has nonvolatile acidity and alkalinity components as conservative quantities, but not [H +]. Simple algorithms are presented for the determination of the average pH for combinations of samples both above and below pH 5.6. Averaging the nonconservative quantity [H +] yields erroneously low mean pH values. To extend the open CO 2 system to include other volatile atmospheric acids and bases distributed among the gas, liquid and particulate matter phases, a theoretical framework for atmospheric acidity is presented. Within certain oxidation-reduction limitations, the total atmospheric acidity (but not free acidity) is a conservative quantity. The concept of atmospheric acidity is applied to air-water systems approximating aerosols, fogwater, cloudwater and rainwater. The buffer intensity in hydrometeors is described as a function of net strong acidity, partial pressures of acid and base gases and the water to air ratio. For high liquid to air volume ratios, the equilibrium partial pressures of trace acid and base gases are set by the pH or net acidity controlled by the nonvolatile acid and base concentrations. For low water to air volume ratios as well as stationary state systems such as precipitation scavenging with continuous emissions, the partial pressures of trace gases (NH 3, HCl, HNO 3, SO 2 and CH 3COOH) appear to be of greater or equal importance as carbonate species as buffers in the aqueous phase.

Assessment of nurses' knowledge on evidence-based preventive practices for pressure ulcer risk reduction in patients with impaired mobility.

PubMed

Akese, M I; Adejumo, P O; Ilesanmi, R E; Obilor, H N

2014-09-01

The increase in the prevalence of pressure ulcer among patients with impaired physical mobility has currently been associated with nurses' inadequate knowledge of preventive interventions. To assess nurses' knowledge of pressure ulcer identification/staging, risk factors and evidence-based preventive practices. This descriptive study was carried out at the University Teaching Hospital Maiduguri (UMTH), Borno State, Nigeria. Total sampling technique was utilized in the recruitment of the study participants. An adapted 75-item-pressure ulcer questionnaire was used for data collection. The data were analyzed using SPSS version 16. The hypotheses on nurses' knowledge were tested at 0.05 level of significance using Chi square test. A total of 219 nurses participated in this study with response rate of 68.0%. The nurses' years of professional practice ranged from 1 to 35 years with a mean of 11.7 (± 7.8) years. Approximately, 73% of the nurses demonstrated a low level of knowledge of pressure ulcer identification/staging, 69.4% demonstrated an average level of knowledge of risk factors and 79.9% demonstrated high level of knowledge of preventive practices. The relationship between nurses' knowledge of risk factors and knowledge of preventive practices (p = 0.37) was not significant. Nurses demonstrated a knowledge deficit in core areas on pressure ulcer identification/staging, risk factors' assessment and evidence-based preventive practices. In order to address this dearth, there is a need to institute an educational-based practice-guideline on pressure ulcer prevention for nurses.

Development of gait segmentation methods for wearable foot pressure sensors.

PubMed

Crea, S; De Rossi, S M M; Donati, M; Reberšek, P; Novak, D; Vitiello, N; Lenzi, T; Podobnik, J; Munih, M; Carrozza, M C

2012-01-01

We present an automated segmentation method based on the analysis of plantar pressure signals recorded from two synchronized wireless foot insoles. Given the strict limits on computational power and power consumption typical of wearable electronic components, our aim is to investigate the capability of a Hidden Markov Model machine-learning method, to detect gait phases with different levels of complexity in the processing of the wearable pressure sensors signals. Therefore three different datasets are developed: raw voltage values, calibrated sensor signals and a calibrated estimation of total ground reaction force and position of the plantar center of pressure. The method is tested on a pool of 5 healthy subjects, through a leave-one-out cross validation. The results show high classification performances achieved using estimated biomechanical variables, being on average the 96%. Calibrated signals and raw voltage values show higher delays and dispersions in phase transition detection, suggesting a lower reliability for online applications.

Deuteron Beam Source Based on Mather Type Plasma Focus

NASA Astrophysics Data System (ADS)

Lim, L. K.; Yap, S. L.; Wong, C. S.; Zakaullah, M.

2013-04-01

A 3 kJ Mather type plasma focus system filled with deuterium gas is operated at pressure lower than 1 mbar. Operating the plasma focus in a low pressure regime gives a consistent ion beam which can make the plasma focus a reliable ion beam source. In our case, this makes a good deuteron beam source, which can be utilized for neutron generation by coupling a suitable target. This paper reports ion beam measurements obtained at the filling pressure of 0.05-0.5 mbar. Deuteron beam energy is measured by time of flight technique using three biased ion collectors. The ion beam energy variation with the filling pressure is investigated. Deuteron beam of up to 170 keV are obtained with the strongest deuteron beam measured at 0.1 mbar, with an average energy of 80 keV. The total number of deuterons per shot is in the order of 1018 cm-2.

Incremental costs associated with physician and pharmacist collaboration to improve blood pressure control.

PubMed

Kulchaitanaroaj, Puttarin; Brooks, John M; Ardery, Gail; Newman, Dana; Carter, Barry L

2012-08-01

To compare costs associated with a physician-pharmacist collaborative intervention with costs of usual care. Cost analysis using health care utilization and outcome data from two prospective, cluster-randomized, controlled clinical trials. Eleven community-based medical offices. A total of 496 patients with hypertension; 244 were in the usual care (control) group and 252 were in the intervention group. To compare the costs, we combined cost data from the two trials. Total costs included costs of provider time, laboratory tests, and antihypertensive drugs. Provider time was calculated based on an online survey of intervention pharmacists and the National Ambulatory Medical Care Survey. Cost parameters were taken from the Bureau of Labor Statistics for average wage rates, the Medicare laboratory fee schedule, and a publicly available Web site for drug prices. Total costs were adjusted for patient characteristics. Adjusted total costs were $774.90 in the intervention group and $445.75 in the control group (difference $329.16, p<0.001). In a sensitivity analysis, the difference in adjusted total costs between the two groups ranged from $224.27-515.56. The intervention cost required to have one additional patient achieve blood pressure control within 6 months was $1338.05, determined by the difference in costs divided by the difference in hypertension control rates between the groups ($329.16/24.6%). The cost over 6 months to lower systolic and diastolic blood pressure 1 mm Hg was $36.25 and $94.32, respectively. The physician-pharmacist collaborative intervention increased not only blood pressure control but also the cost of care. Additional research, such as a cost-benefit or a cost-minimization analysis, is needed to assess whether financial savings related to reduced morbidity and mortality achieved from better blood pressure control outweigh the cost of the intervention. © 2012 Pharmacotherapy Publications, Inc. All rights reserved.

Contact stresses, pressure and area in a fixed-bearing total ankle replacement: a finite element analysis.

PubMed

Martinelli, Nicolo; Baretta, Silvia; Pagano, Jenny; Bianchi, Alberto; Villa, Tomaso; Casaroli, Gloria; Galbusera, Fabio

2017-11-25

Mobile-bearing ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty to address endstage ankle osteoarthritis preserving joint movement. Alternative solutions used fixed-bearing designs, which increase stability and reduce the risk of bearing dislocation, but with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses, pressure and area in the polyethylene component of a new total ankle replacement with a fixed-bearing design, using 3D finite element analysis. A three-dimensional finite element model of the Zimmer Trabecular Metal Total Ankle was developed and assembled based on computed tomography images. Three different sizes of the polyethylene insert were modeled, and a finite element analysis was conducted to investigate the contact pressure, the von Mises stresses and the contact area of the polyethylene component during the stance phase of the gait cycle. The peak value of pressure was found in the anterior region of the articulating surface, where it reached 19.8 MPa at 40% of the gait cycle. The average contact pressure during the stance phase was 6.9 MPa. The maximum von Mises stress of 14.1 MPa was reached at 40% of the gait cycle in the anterior section. In the central section, the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas in the posterior section the maximum stress of 5.4 MPa was reached at the end of the stance phase. The new fixed-bearing total ankle replacement showed a safe mechanical behavior and many clinical advantages. However, advanced models to quantitatively estimate the wear are need. To the light of the clinical advantages, we conclude that the presented prosthesis is a good alternative to the other products present in the market.

Experimental evaluation of a TF30-P-3 turbofan engine in an altitude facility: Effect of steady-state temperature distortion

NASA Technical Reports Server (NTRS)

Braithwaite, W. M.

1973-01-01

The effects of circumferential distortion of the total temperature entering 25, 50, and 75 percent of the inlet circumferential annulus of a turbofan engine were determined. Complete compressor stall resulted from distortions of from 14 to 20 percent of the face averaged temperature. Increasing the temperature level in one sector resulted in that sector moving toward stall by decreasing the equivalent rotor speeds while the pressure ratio remained approximately constant. Stall originated as a rotating zone in the low-pressure compressor which resulted as a terminal stall in the high-pressure compressor. Decreasing the Reynolds number index to 0.25 from 0.5 reduced the required distortion for stall by 50 percent for the conditions investigated.

First-Principles Studies of Pentaerythritol Tetranitrate (PETN) Single Crystal Unit Cell Volumes and Vibrational Frequencies under Hydrostatic Pressure

NASA Astrophysics Data System (ADS)

Perger, Warren F.; Zhao, Jijun; Winey, J. M.; Gupta, Y. M.

2006-07-01

The vibrational frequencies of the PETN molecular crystal were calculated using the first-principles CRYSTAL03 program which employs an all-electron LCAO approach and calculates analytic first derivatives of the total energy with respect to atomic displacements. Numerical second derivatives were used to enable calculation of the vibrational frequencies at ambient pressure and under various states of compression. Three different density functionals, B3LYP, PW91, and X3LYP were used to examine the effect of the exchange-correlation functional on the vibrational frequencies. The average deviation with experimental results is shown to be on the order of 2-3%, depending on the functional used. The pressure-induced shift of the vibrational frequencies is presented.

Diagnostics of ion beam generated from a Mather type plasma focus device

NASA Astrophysics Data System (ADS)

Lim, L. K.; Ngoi, S. K.; Wong, C. S.; Yap, S. L.

2014-03-01

Diagnostics of ion beam emission from a 3 kJ Mather-type plasma focus device have been performed for deuterium discharge at low pressure regime. Deuterium plasma focus was found to be optimum at pressure of 0.2 mbar. The energy spectrum and total number of ions per shot from the pulsed ion beam are determined by using biased ion collectors, Faraday cup, and solid state nuclear track detector CR-39. Average energy of the ion beam obtained is about 60 keV. Total number of the ions has been determined to be in the order of 1011 per shot. Solid state nuclear track detectors (SSNTD) CR39 are employed to measure the particles at all angular direction from end on (0°) to side on (90°). Particle tracks are registered by SSNTD at 30° to 90°, except the one at the end-on 0°.

Investigation on centrifugal impeller in an axial-radial combined compressor with inlet distortion

NASA Astrophysics Data System (ADS)

Li, Du; Yang, Ce; Zhao, Ben; Zhou, Mi; Qi, Mingxu; Zhang, Jizhong

2011-12-01

Assembling an axial rotor and a stator at centrifugal compressor upstream to build an axial-radial combined compressor could achieve high pressure ratio and efficiency by appropriate size augment. Then upstream potential flow and wake effect appear at centrifugal impeller inlet. In this paper, the axial-radial compressor is unsteadily simulated by three-dimensional Reynolds averaged Navier-Stokes equations with uniform and circumferential distorted total pressure inlet condition to investigate upstream effect on radial rotor. The results show that span-wise nonuniform total pressure distribution is generated and radial and circumferential combined distortion is formed at centrifugal rotor inlet. The upstream stator wake deflects to rotor rotation direction and decreases with blade span increases. Circumferential distortion causes different separated flow formations at different pitch positions. The tip leakage vortex is suppressed in centrifugal blade passages. Under distorted inlet condition, flow direction of centrifugal impeller leading edge upstream varies evidently near hub and shroud but varies slightly at mid-span. In addition, compressor stage inlet distortion produces remarkable effect on blade loading of centrifugal blade both along chordwise and pitchwise.

Influence of hydrostatic pressure on dynamics and spatial distribution of protein partial molar volume: time-resolved surficial Kirkwood-Buff approach.

PubMed

Yu, Isseki; Tasaki, Tomohiro; Nakada, Kyoko; Nagaoka, Masataka

2010-09-30

The influence of hydrostatic pressure on the partial molar volume (PMV) of the protein apomyoglobin (AMb) was investigated by all-atom molecular dynamics (MD) simulations. Using the time-resolved Kirkwood-Buff (KB) approach, the dynamic behavior of the PMV was identified. The simulated time average value of the PMV and its reduction by 3000 bar pressurization correlated with experimental data. In addition, with the aid of the surficial KB integral method, we obtained the spatial distributions of the components of PMV to elucidate the detailed mechanism of the PMV reduction. New R-dependent PMV profiles identified the regions that increase or decrease the PMV under the high pressure condition. The results indicate that besides the hydration in the vicinity of the protein surface, the outer space of the first hydration layer also significantly influences the total PMV change. These results provide a direct and detailed picture of pressure induced PMV reduction.

The effects of a 12-week worksite physical activity intervention on anthropometric indices, blood pressure indices, and plasma biomarkers of cardiovascular disease risk among university employees.

PubMed

Corbett, Duane B; Fennell, Curtis; Peroutky, Kylene; Kingsley, J Derek; Glickman, Ellen L

2018-01-29

To determine the effectiveness of a low-cost 12-week worksite physical activity intervention targeting a goal of 10,000 steps per day on reducing anthropometric indices, blood pressure indices, and plasma biomarkers of cardiovascular disease (CVD) risk among the employees of a major university. Fifty university employees (n = 43 female, n = 7 male; mean age = 48 ± 10 years) participated in the 12-week physical activity intervention (60 min, 3 day/week). Each session included both aerobic (cardiorespiratory endurance) and muscle-strengthening (resistance) physical activity using existing university facilities and equipment. Anthropometric indices, blood pressure indices, and plasma biomarkers of CVD risk assessed included those for obesity (body mass index), hypertension (systolic blood pressure, SBP; diastolic blood pressure, DBP), dyslipidemia (high-density lipoprotein, HDL; low-density lipoprotein, LDL; total serum cholesterol), and prediabetes (impaired fasting glucose, IFG). Steps per day were assessed using a wrist-worn activity monitor. Participants were given the goal of 10,000 steps per day and categorized as either compliers (≥ 10,000 steps per day on average) or non-compliers (< 10,000 steps per day on average) based on their ability to achieve this goal. Overall, 34% of participants at baseline were already at an elevated risk of CVD due to age. On average, 28% of participants adhered to the goal of 10,000 steps per day. After 12-weeks, participants in both groups (compliers and non-compliers) had lower BMI scores (p < 0.001), lower HDL scores (p < 0.034), and higher IFG scores (p < 0.001). The non-compliers had a greater reduction of BMI scores than the compliers (p = 0.003). Participants at risk for CVD had greater reductions than those not at risk for several risk factors, including SBP (p = 0.020), DBP (p = 0.028), IFG (p = 0.002), LDL (p = 0.006), and total serum cholesterol (p = 0.009). While the physical activity intervention showed mixed results overall with both favorable changes in anthropometric indices yet unfavorable changes in plasma biomarkers, it was particularly beneficial in regards to both blood pressure indices and plasma biomarkers among those already at risk of CVD. Trial registration ClinicalTrials.gov NCT03385447; retrospectively registered.

Energy transfers in internal tide generation, propagation and dissipation in the deep ocean

NASA Astrophysics Data System (ADS)

Floor, J. W.; Auclair, F.; Marsaleix, P.

The energy transfers associated with internal tide (IT) generation by a semi-diurnal surface tidal wave impinging on a supercritical meridionally uniform deep ocean ridge on the f-plane, and subsequent IT-propagation are analysed using the Boussinesq, free-surface, terrain-following ocean model Symphonie. The energy diagnostics are explicitly based on the numerical formulation of the governing equations, permitting a globally conservative, high-precision analysis of all physical and numerical/artificial energy transfers in a sub-domain with open lateral boundaries. The net primary energy balances are quantified using a moving average of length two tidal periods in a simplified control simulation using a single time-step, minimal diffusion, and a no-slip sea floor. This provides the basis for analysis of enhanced vertical and horizontal diffusion and a free-slip bottom boundary condition. After a four tidal period spin-up, the tidally averaged (net) primary energy balance in the generation region, extending ±20 km from the ridge crest, shows that the surface tidal wave loses approximately C = 720 W/m or 0.3% of the mean surface tidal energy flux (2.506 × 10 5 W/m) in traversing the ridge. This corresponds mainly to the barotropic-to-baroclinic energy conversion due to stratified flow interaction with sloping topography. Combined with a normalised net advective flux of baroclinic potential energy of 0.9 × C this causes a net local baroclinic potential energy gain of 0.72 × C and a conversion into baroclinic kinetic energy through the baroclinic buoyancy term of 1.18 × C. Tidally averaged, about 1.14 × C is radiated into the abyssal ocean through the total baroclinic flux of internal pressure associated with the IT- and background density field. This total baroclinic pressure flux is therefore not only determined by the classic linear surface-to-internal tide conversion, but also by the net advection of baroclinic (background) potential energy, indicating the importance of local processes other than linear IT-motion. In the propagation region (PR), integrated over the areas between 20 and 40 km from the ridge crest, the barotropic and baroclinic tide are decoupled. The net incoming total baroclinic pressure flux is balanced by local potential energy gain and outward baroclinic flux of potential energy associated with the total baroclinic density. The primary net energy balances are robust to changes in the vertical diffusion coefficient, whereas relatively weak horizontal diffusion significantly reduces the outward IT energy flux. Diapycnal mixing due to vertical diffusion causes an available potential energy loss of about 1% of the total domain-averaged potential energy gain, which matches {km-1}/{km}ρ0KVN2 to within 0.5%, for km linearly distributed grid-levels and constant background density ρ0, vertical diffusivity ( KV) and buoyancy frequency ( N).

Retrospective, nonrandomized controlled study on autoadjusting, dual-pressure positive airway pressure therapy for a consecutive series of complex insomnia disorder patients

PubMed Central

Krakow, Barry; McIver, Natalia D; Ulibarri, Victor A; Nadorff, Michael R

2017-01-01

Purpose Emerging evidence shows that positive airway pressure (PAP) treatment of obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) in chronic insomnia patients (proposed “complex insomnia” disorder) leads to substantial decreases in insomnia severity. Although continuous PAP (CPAP) is the pressure mode most widely researched, intolerance to fixed pressurized air is rarely investigated or described in comorbidity patients. This retrospective study examined dual pressure, autoadjusting PAP modes in chronic, complex insomnia disorder patients. Patients and methods Chronic insomnia disorder patients (mean [SD] insomnia severity index [ISI] =19.11 [3.34]) objectively diagnosed with OSA or UARS and using either autobilevel PAP device or adaptive servoventilation (ASV) device after failing CPAP therapy (frequently due to intolerance to pressurized air, poor outcomes, or emergence of CSA) were divided into PAP users (≥20 h/wk) and partial users (<20 h/wk) for comparison. Subjective and objective baseline and follow-up measures were analyzed. Results Of the 302 complex insomnia patients, PAP users (n=246) averaged 6.10 (1.78) nightly hours and 42.71 (12.48) weekly hours and partial users (n=56) averaged 1.67 (0.76) nightly hours and 11.70 (5.31) weekly hours. For mean (SD) decreases in total ISI scores, a significant (group × time) interaction was observed (F[1,300]=13.566; P<0.0001) with PAP users (–7.59 [5.92]; d=1.63) showing superior results to partial users (−4.34 [6.13]; d=0.81). Anecdotally, patients reported better tolerability with advanced PAP compared to previous experience with CPAP. Both adaptive servoventilation and autobilevel PAP showed similar ISI score improvement without statistical differences between devices. Total weekly hours of PAP use correlated inversely with change in insomnia symptoms (r=−0.256, P<0.01). Conclusion Insomnia severity significantly decreased in patients using autoadjusting PAP devices, but the study design restricts interpretation to an association. Future research must elucidate the interaction between insomnia and OSA/UARS as well as the adverse influence of pressure intolerance on PAP adaptation in complex insomnia patients. Randomized controlled studies must determine whether advanced PAP modes provide benefits over standard CPAP modes in these comorbidity patients. PMID:28331381

Measuring Time-Averaged Blood Pressure

NASA Technical Reports Server (NTRS)

Rothman, Neil S.

1988-01-01

Device measures time-averaged component of absolute blood pressure in artery. Includes compliant cuff around artery and external monitoring unit. Ceramic construction in monitoring unit suppresses ebb and flow of pressure-transmitting fluid in sensor chamber. Transducer measures only static component of blood pressure.

Identification of the Optimal Protocol for Automated Office Blood Pressure Measurement Among Patients With Treated Hypertension.

PubMed

Moore, Myles N; Schultz, Martin G; Nelson, Mark R; Black, J Andrew; Dwyer, Nathan B; Hoban, Ella; Jose, Matthew D; Kosmala, Wojciech; Przewlocka-Kosmala, Monika; Zachwyc, Jowita; Otahal, Petr; Picone, Dean S; Roberts-Thomson, Philip; Veloudi, Panagiota; Sharman, James E

2018-02-09

Automated office blood pressure (AOBP) involving repeated, unobserved blood pressure (BP) readings during one clinic visit is recommended for in-office diagnosis and assessment of hypertension. However, the optimal AOBP protocol to determine BP control in the least amount of time with the fewest BP readings is yet to be determined and was the aim of this study. One hundred and eighty-nine patients (mean age 62.8 ± 12.1 years; 50.3% female) with treated hypertension referred to specialist clinics at 2 sites underwent AOBP in a quiet room alone. Eight BP measurements were taken starting immediately after sitting and then at 2-minute intervals (15 minutes total). The optimal AOBP protocol was defined by the smallest mean difference and highest intraclass correlation coefficient (ICC) compared with daytime ambulatory BP (ABP). The same BP device (Mobil-o-graph, IEM) was used for both AOBP and daytime ABP. Average 15-minute AOBP and daytime ABP were 134 ± 22/82 ± 13 and 137 ± 17/83 ± 11 mm Hg, respectively. The optimal AOBP protocol was derived within a total duration of 6 minutes from the average of 2 measures started after 2 and 4 minutes of seated rest (systolic BP: mean difference (95% confidence interval) 0.004(-2.21, 2.21) mm Hg, P = 1.0; ICC = 0.81; diastolic BP: mean difference 0.37(-0.90, 1.63) mm Hg, P = 0.57; ICC = 0.86). AOBP measures taken after 8 minutes tended to underestimate daytime ABP (whether as a single BP or the average of more than 1 BP reading). Only 2 AOBP readings taken over 6 minutes (excluding an initial reading immediately after sitting) may be needed to be comparable with daytime ABP. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Instantaneous, phase-averaged, and time-averaged pressure from particle image velocimetry

NASA Astrophysics Data System (ADS)

de Kat, Roeland

2015-11-01

Recent work on pressure determination using velocity data from particle image velocimetry (PIV) resulted in approaches that allow for instantaneous and volumetric pressure determination. However, applying these approaches is not always feasible (e.g. due to resolution, access, or other constraints) or desired. In those cases pressure determination approaches using phase-averaged or time-averaged velocity provide an alternative. To assess the performance of these different pressure determination approaches against one another, they are applied to a single data set and their results are compared with each other and with surface pressure measurements. For this assessment, the data set of a flow around a square cylinder (de Kat & van Oudheusden, 2012, Exp. Fluids 52:1089-1106) is used. RdK is supported by a Leverhulme Trust Early Career Fellowship.

Optimization of supercritical carbon dioxide extraction of Piper Betel Linn leaves oil and total phenolic content

NASA Astrophysics Data System (ADS)

Aziz, A. H. A.; Yunus, M. A. C.; Arsad, N. H.; Lee, N. Y.; Idham, Z.; Razak, A. Q. A.

2016-11-01

Supercritical Carbon Dioxide (SC-CO2) Extraction was applied to extract piper betel linn leaves. The piper betel leaves oil was used antioxidant, anti-diabetic, anticancer and antistroke. The aim of this study was to optimize the conditions of pressure, temperature and flowrate for oil yield and total phenolic content. The operational conditions of SC-CO2 studied were pressure (10, 20, 30 MPa), temperature (40, 60, 80 °C) and flowrate carbon dioxide (4, 6, 8 mL/min). The constant parameters were average particle size and extraction regime, 355pm and 3.5 hours respectively. First order polynomial expression was used to express the extracted oil while second order polynomial expression was used to express the total phenolic content and the both results were satisfactory. The best conditions to maximize the total extraction oil yields and total phenolic content were 30 MPa, 80 °C and 4.42 mL/min leading to 7.32% of oil and 29.72 MPa, 67.53 °C and 7.98 mL/min leading to 845.085 mg GAE/g sample. In terms of optimum condition with high extraction yield and high total phenolic content in the extracts, the best operating conditions were 30 MPa, 78 °C and 8 mL/min with 7.05% yield and 791.709 mg gallic acid equivalent (GAE)/g sample. The most dominant condition for extraction of oil yield and phenolic content were pressure and CO2 flowrate. The results show a good fit to the proposed model and the optimal conditions obtained were within the experimental range with the value of R2 was 96.13% for percentage yield and 98.52% for total phenolic content.

Border-Crossing Model for the Diffusive Coarsening of Wet Foams

NASA Astrophysics Data System (ADS)

Durian, Douglas; Schimming, Cody

For dry foams, the transport of gas from small high-pressure bubbles to large low-pressure bubbles is dominated by diffusion across the thin soap films separating neighboring bubbles. For wetter foams, the film areas become smaller as the Plateau borders and vertices inflate with liquid. So-called ``border-blocking'' models can explain some features of wet-foam coarsening based on the presumption that the inflated borders totally block the gas flux; however, this approximation dramatically fails in the wet/unjamming limit where the bubbles become close-packed spheres. Here, we account for the ever-present border-crossing flux by a new length scale defined by the average gradient of gas concentration inside the borders. We argue that it is proportional to the geometric average of film and border thicknesses, and we verify this scaling and the numerical prefactor by numerical solution of the diffusion equation. Then we show how the dA / dt =K0 (n - 6) von Neumann law is modified by the appearance of terms that depend on bubble size and shape as well as the concentration gradient length scale. Finally, we use the modified von Neumann law to compute the growth rate of the average bubble, which is not constant.

Preliminary Results of Altitude-Wind-Tunnel Investigation of X24C-4B Turbojet Engine. I - Pressure and Temperature Distributions

NASA Technical Reports Server (NTRS)

Prince, William R.; Hawkins, W. Kent

1947-01-01

Pressures and temperatures throughout the X24C-4B turbojet engine are presented in both tabular and graphical forms to show the effect of altitude, flight Mach number, and engine speed on the internal operation of the engine. These data were obtained in the NACA Cleveland altitude wind tunnel at simulated altitudes from 5000 to 45,000 feet, simulated flight Mach numbers from 0.25 to 1.08, and engine speeds from 4000 to 12,500 rpm. Location and detail drawings of the instrumentation installed at seven survey stations in the engine are shown. Application of generalization factors to pressures and temperatures at each measuring station for the range of altitudes investigated showed that the data did not generalize above an altitude of 25,000 feet. Total-pressure distribution at the compressor outlet varied only with change in engine speed. At altitudes above 35,000 feet and engine speeds above 11,000 rpm, the peak temperature at the turbine-outlet annulus moved inward toward the root of the blade, which is undesirable from blade-stress considerations. The temperature levels at the turbine outlet and the exhaust-nozzle outlet were lowered as the Mach number was increased. The static-pressure measurements obtained at each stator stage of the compressor showed a pressure drop through the inlet guide vanes and the first-stage rotor at high engine speeds. The average values measured by the manufacturer's instrumentation werein close agreement with the average values obtained with NACA instrumentation.

Computer program for analysis of hemodynamic response to head-up tilt test

NASA Astrophysics Data System (ADS)

ŚwiÄ tek, Eliza; Cybulski, Gerard; Koźluk, Edward; PiÄ tkowska, Agnieszka; Niewiadomski, Wiktor

2014-11-01

The aim of this work was to create a computer program, written in the MATLAB environment, which enables the visualization and analysis of hemodynamic parameters recorded during a passive tilt test using the CNS Task Force Monitor System. The application was created to help in the assessment of the relationship between the values and dynamics of changes of the selected parameters and the risk of orthostatic syncope. The signal analysis included: R-R intervals (RRI), heart rate (HR), systolic blood pressure (sBP), diastolic blood pressure (dBP), mean blood pressure (mBP), stroke volume (SV), stroke index (SI), cardiac output (CO), cardiac index (CI), total peripheral resistance (TPR), total peripheral resistance index (TPRI), ventricular ejection time (LVET) and thoracic fluid content (TFC). The program enables the user to visualize waveforms for a selected parameter and to perform smoothing with selected moving average parameters. It allows one to construct the graph of means for any range, and the Poincare plot for a selected time range. The program automatically determines the average value of the parameter before tilt, its minimum and maximum value immediately after changing positions and the times of their occurrence. It is possible to correct the automatically detected points manually. For the RR interval, it determines the acceleration index (AI) and the brake index (BI). It is possible to save calculated values to an XLS with a name specified by user. The application has a user-friendly graphical interface and can run on a computer that has no MATLAB software.

Relationship Between Depression and Specific Health Indicators Among Hypertensive African American Parents and Grandparents

PubMed Central

Taylor, Jacquelyn Y.; Washington, Olivia G. M.; Artinian, Nancy T.; Lichtenberg, Peter

2010-01-01

African Americans are at greater risk for hypertension than are other ethnic groups. This study examined relationships among hypertension, stress, and depression among 120 urban African American parents and grandparents. This study is a secondary analysis of a larger nurse-managed randomized clinical trial testing the effectiveness of a telemonitoring intervention. Baseline data used in analyses, with the exception of medication compliance, were collected at 3 months' follow-up. Health indicators, perceived stress, and social support were examined to determine their relationship with depressive symptoms. A total of 48% of the variance in depressive symptomology was explained by perceived stress and support. Health indicators including average systolic blood pressure explained 21% of the variance in depressive symptomology. The regression analysis using average diastolic blood pressure explained 26% of the variance in depressive symptomology. Based on study results, African Americans should be assessed for perceived stress and social support to alleviate depressive symptomology. PMID:18843828

[Low-dose omega-3 fatty acids as lipid lowering agents in the practice. A field study of ambulatory patients in general practice].

PubMed

Zakaria, B; Bertsch, S

1992-04-10

BASICS: Clinical trials have shown that omega-3 fatty acids are also effective at smaller doses than those so far recommended for lowering lipid concentrations. Testing this finding in a large number of unselected outpatients. Open multicentric trial involving 197 patients with dyslipoproteinemia. Treatment comprised omega-3 fatty acids, 1.1 to 1.4 g per day administered for a period of 12 weeks. After 12 weeks of treatment, serum triglycerides decreased on average by about 23%, total cholesterol by about 10%, and LDL cholesterol by about 5%. HDL cholesterol rose by an average of 16%. The fish oil preparation (Eicosapen, Nycomed, Munich) was well tolerated; a fishy taste and mild gastrointestinal complaints led to discontinuation of treatment in only four cases. It was also found that the effect of omega-3 fatty acids was appreciably greater in hypertensives than in patients with normal blood pressure--not only on systolic and diastolic blood pressure, but also on serum triglycerides and HDL.

Errors in calculated oncotic pressure of dog plasma.

PubMed

Gabel, J C; Scott, R L; Adair, T H; Drake, R E; Traber, D L

1980-12-01

Several equations to calculate plasma oncotic pressure (pi) from the total protein concentration (C) have been previously described. These equations were derived empirically from samples with a wide range of C obtained by diluting or concentrating normal plasma samples. To test these equations over a range of naturally occurring C, we measured C and pi of plasma samples from 40 dogs. C ranged from 5.3 to 8.7 g/dl and averaged 6.5 +/- 0.1 (mean +/- SE) and pi averaged 17.9 +/- 0.3 mmHg. The regression equation was pi = 78.14 + 1.67 C (r = 0.74). pi increased with C much less than predicted with the commonly used equations. The albumin-to-globulin concentration ratios (A/G), determined in 27 of the dogs, decreased with increasing C (A/G = 1.56-0.128 C, r = 0.62). The lower A/G at the higher C's could cause the lower than predicted increase in pi with C, because the equations were developed from data in which A/G was constant.

Trends in Biometric Health Indices Within an Employer-Sponsored Wellness Program With Outcome-Based Incentives.

PubMed

Fu, Patricia Lin; Bradley, Kent L; Viswanathan, Sheila; Chan, June M; Stampfer, Meir

2016-07-01

To evaluate changes in employees' biometrics over time relative to outcome-based incentive thresholds. Retrospective cohort analysis of biometric screening participants (n = 26 388). Large employer primarily in Western United States. Office, retail, and distribution workforce. A voluntary outcome-based biometric screening program, incentivized with health insurance premium discounts. Body mass index (BMI), cholesterol, blood glucose, blood pressure, and nicotine. Followed were participants from their first year of participation, evaluating changes in measures. On average, participants who did not meet the incentive threshold at baseline decreased their BMI (1%), glucose (8%), blood pressure (systolic 9%, diastolic 8%), and total cholesterol (8%) by year 2 with improvements generally sustained or continued during each additional year of participation. On average, individuals at high health risk who participated in a financially incentivized biometric assessment program improved their health indices over time. Further research is needed to understand key determinants that drive health improvement indicated here. © The Author(s) 2016.

Correlation between the season, temperature and atmospheric pressure with incidence and pathogenesis of acute appendicitis.

PubMed

Karanikolić, Aleksandar; Karanikolić, Vesna; Djordjević, Lidija; Pešić, Ivan

2016-01-01

There is very little literature data on the correlation between the seasons, temperature and atmospheric pressure, and pathogenesis of acute appendicitis (AA). The aim of this research is to investigate the association between the seasons, changes in atmospheric temperature and pressure, and patients’ age and severity of the clinical form of AA in the city of Niš This study included 395 patients diagnosed with AA, who, during the two-year period, from July 1st 2011 to June 30th 2013, were hospitalized and operated on at the Department of General Surgery, Clinical Center in Niš, Serbia. The increased average daily values of barometric pressure by 1 millibar on the day when the event took place was associated (p < 0.05) with the decrease of total risk of the occurrence of appendicitis by 2.2% (0.2–4.1%). In all observed patients, each increase of the mean daily temperature by 1°C three days before the event took place (Lag 3) was associated (p < 0.05) with the increase of total risk of the occurrence of appendicitis by 1.3% (0.1–2.5%). According to the results of this research, we can conclude that patients’ sex, age and severity of the clinical form of AA are not in connection with the seasons, while there are certain connections between appendicitis occurrence and atmospheric temperature and pressure.

Osmotic effects of polyethylene glycol.

PubMed

Schiller, L R; Emmett, M; Santa Ana, C A; Fordtran, J S

1988-04-01

Polyethylene glycol (PEG) has been used to increase the osmotic pressure of fluids used to cleanse the gastrointestinal tract. However, little is known about its osmotic activity. To investigate this activity systematically, solutions of PEG of differing molecular weights were made and subjected to measurement of osmolality by both freezing point depression and vapor pressure osmometry. Measured osmolality was increasingly greater than predicted from average molecular weight as PEG concentration increased. Measurement of sodium activity in NaCl/PEG solutions by means of an ion-selective electrode suggested that the higher than expected osmolality could be due in part to interactions that, in effect, sequestered water from the solution. Osmolality was consistently greater by freezing point osmometry than by vapor pressure osmometry. To determine which osmometry method reflected biologically relevant osmolality, normal subjects underwent steady-state total gut perfusion with an electrolyte solution containing 105 g/L of PEG 3350. This produced rectal effluent that was hypertonic by freezing point osmometry but isotonic by vapor pressure osmometry. Assuming that luminal fluid reaches osmotic equilibrium with plasma during total gut perfusion, this result suggests that the vapor pressure osmometer accurately reflects the biologically relevant osmolality of intestinal contents. We conclude that PEG exerts more of an osmotic effect than would be predicted from its molecular weight. This phenomenon may reflect interactions between PEG and water molecules that alter the physical chemistry of the solution and sequester water from the solution.

Exploring pharmacist-customer communication: the established blood pressure measurement episode.

PubMed

Cavaco, Afonso Neves; Romano, João P

2010-10-01

To characterize the communication ritual in the pharmacist-customer dyad during a blood pressure measurement and counselling episode. A Portuguese urban community pharmacy. An exploratory, cross-sectional design was used. Participants were purposively selected and data collected via audio recording, as well as demographics and clinical information via questionnaire. Encounters' verbal content was transcribed verbatim, utterances identified, time stamped, and classified according to a coding scheme of fifteen categories. All data was statistically analyzed using SPSSv17. Four dialogue structures: speaker turn, interactivity, turn density and turn duration measurements. From a total of 51 participants, 72.5% were female with a median age of 66 years. The average systolic blood pressure was 140 mmHg, while the diastolic was 78 mmHg. The blood pressure measurement episode lasted for 5:35 min, with an average of 81 utterances. From all utterances registered, 55.3% were produced by the customer. Visits averaged 38 speaker turns, with an interactivity rate of approximately 7 turns per episode minute. For pharmacists, turn duration averaged 7.0 s and turn density 2.1 utterances. The customers' turns comprised a mean of 8.0 s, with 2.4 utterances. Longer episodes were related to more speaker turns and greater customer turn density and duration, but lower dialogue interactivity. The interactivity rate was also lower when the customers' utterances increased. Pharmacists asked more questions (essentially closed ones), while the customers gave more information. No significant associations were observed between elderly/non-elderly and gender in relation to all communication variables. However, an increased number of speaker turns and closed-questions were associated to a higher systolic pressure. It seems that pharmacists tend to control the content of the dialogue, while customers have more influence on the visit duration and interactivity. Specific hypertensive episodes induce a higher information search. Since the closed questioning format was prevalent, it seems that open information exchange was limited, mainly serving confirmation purposes rather than having a true exploratory nature. Although talk dominance is balanced, further analysis is required to better inform these results, which would confirm the low interactivity and the reduced information-seeking behaviour showed in the counselling episodes.

Protective effects of green tea on olanzapine-induced-metabolic syndrome in rats.

PubMed

Razavi, Bibi Marjan; Lookian, Fariba; Hosseinzadeh, Hossein

2017-08-01

Atypical antipsychotics particularly olanzapine are associated with obesity and serious metabolic disturbances. As green tea (Camellia sinensis) is generally associated with beneficial effects on obesity and other metabolic disturbances, this study was undertaken to evaluate the effect of green tea aqueous extract (GTAE) on olanzapine induced weight gain and metabolic abnormalities in rats. Male Wistar rats were divided into eight groups: control, olanzapine (5mg/kg/day, IP.), GTAE (25, 50 and 100mg/kg/day, IP.) plus olanzapine and GTAE (25, 50 and 100mg/kg/day, IP.). Treatments were continued for 11 days. Body weight gain, average food and water intake were measured during the experiment. Plasma lipid, glucose and leptin levels, mean systolic blood pressure and total locomotion were evaluated at the end of experiment. Olanzapine induced significant weight gain at the end of treatment (10.38% of body weight) when compared to control (3.13% of body weight) in male Wistar rats. Average food and water intake were increased by olanzapine treatment. 11days olanzapine administration led to hyperleptinemia, hyperglycemia and dyslipidemia. Olanzapine also increased mean systolic blood pressure and decreased total locomotion. GTAE decreased significantly body weight gain and average food and water intake, improved the changes in lipid profile as well as fasting blood glucose, and finally decreased hyperleptinemia and hypertension induced by olanzapine. Results of this study demonstrated that GTAE could exert protective effects against olanzapine induced obesity partially due to its lowering effect on leptin. GTAE improved other metabolic abnormalities including dyslipidemia, hyperglycemia and hypertension induced by olanzapine in rats. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Comparison of renal pelvic pressure and postoperative fever incidence between standard- and mini-tract percutaneous nephrolithotomy.

PubMed

Wu, Cheng; Hua, Li-Xin; Zhang, Jian-Zhong; Zhou, Xun-Rong; Zhong, Wei; Ni, Hao-Dong

2017-01-01

This study was proposed to compare the clinical effectiveness of mini-tract percutaneous nephrolithotomy (MPCNL) with standard-tract percutaneous nephrolithotomy (SPCNL) and verify whether MPCNL is associated with both higher renal pelvic pressure (RPP) and incidence of postoperative fever. A total of 228 patients with kidney stone were randomly allocated to the MPCNL group (n=114) and SPCNL group (n=114). Both intraoperative and postoperative indexes along with the incidence of complications were compared between the two treatment groups. RPP was measured using a baroreceptor which was connected to an open-ended ureteric catheter during the operation of percutaneous nephrolithotomy. The MPCNL group exhibited significantly longer average operation time, more average amount of flush water, and lesser average amount of bleeding during the operation than the SPCNL group (p<0.05). Moreover, significantly lesser average amount of postoperative serum creatinine, shorter average hospital stay, and more average amount of postoperative hemoglobin were observed in the MPCNL group than in the SPCNL group (p<0.05). MPCNL were more applicable to clear caliceal stones (p<0.05), whereas SPCNL were more effective for the removal of simple pelvic stones. The difference in the incidence of postoperative fever between the two treatment groups also appeared to be significant (p<0.05). Logistic regression provided solid evidence that both RPP and its accumulation time at which RPP≥30 mmHg significantly affected the incidence of postoperative fever. MPCNL was correlated with both higher RPP and increased likelihood of postoperative fever compared with SPCNL. Copyright © 2016 The Authors. Published by Elsevier Taiwan.. All rights reserved.

The daytime course of total ozone content caused by cloud convection

NASA Technical Reports Server (NTRS)

Ishov, Alexander G.

1994-01-01

Presented are the experimental data on the daytime course of the total O3 and SO2 content obtained by Brewer 044 spectrophotometer in the tropics (Thumba, India, 8.53 N, 76.87 W, March-May 1990) and at middle latitudes (Obninsk, Russia, 55.12 N, 36.6 W, May-October 1991) of the Northern Hemisphere. The analysis showed that under fine warm weather conditions without precipitation (air mass change and frontal passage were not observed during several days) in days with well-developed convective clouds (cloudless morning, convective clouds in the daytime, no clouds in the evening) there is a typical nearly symmetric (with respect to local noon) course of the total O3 (with the minimum at about local noon) and SO2 (with the maximum at about local noon) content. The minimum depth is about 2-5 percent of the average daytime values of the total ozone content. The synchronous measurements of pressure pulsations with microbarograph (they are the indicator of convective and turbulent motion development in the lower subcloud atmospheric layer) showed that during these days there is a nearly symmetric course of pressure pulsations with the maximum at about local noon.

Three-dimensional unsteady flow calculations in an advanced gas generator turbine

NASA Technical Reports Server (NTRS)

Rangwalla, Akil A.

1993-01-01

This paper deals with the application of a three-dimensional, unsteady Navier-Stokes code for predicting the unsteady flow in a single stage of an advanced gas generator turbine. The numerical method solves the three-dimensional thin-layer Navier-Stokes equations, using a system of overlaid grids, which allow for relative motion between the rotor and stator airfoils. Results in the form of time averaged pressures and pressure amplitudes on the airfoil surfaces will be shown. In addition, instantaneous contours of pressure, Mach number, etc. will be presented in order to provide a greater understanding of the inviscid as well as the viscous aspects of the flowfield. Also, relevant secondary flow features such as cross-plane velocity vectors and total pressure contours will be presented. Prior work in two-dimensions has indicated that for the advanced designs, the unsteady interactions can play a significant role in turbine performance. These interactions affect not only the stage efficiency but can substantially alter the time-averaged features of the flow. This work is a natural extension of the work done in two-dimensions and hopes to address some of the issues raised by the two-dimensional calculations. These calculations are being performed as an integral part of an actual design process and demonstrate the value of unsteady rotor-stator interaction calculations in the design of turbomachines.

Predictive validity of granulation tissue color measured by digital image analysis for deep pressure ulcer healing: a multicenter prospective cohort study.

PubMed

Iizaka, Shinji; Kaitani, Toshiko; Sugama, Junko; Nakagami, Gojiro; Naito, Ayumi; Koyanagi, Hiroe; Konya, Chizuko; Sanada, Hiromi

2013-01-01

This multicenter prospective cohort study examined the predictive validity of granulation tissue color evaluated by digital image analysis for deep pressure ulcer healing. Ninety-one patients with deep pressure ulcers were followed for 3 weeks. From a wound photograph taken at baseline, an image representing the granulation red index (GRI) was processed in which a redder color represented higher values. We calculated the average GRI over granulation tissue and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) and wound surface (%wound red index 80). In the receiver operating characteristics curve analysis, most GRI parameters had adequate discriminative values for both improvement of the DESIGN-R total score and wound closure. Ulcers were categorized by the obtained cutoff points of the average GRI (≤80, >80), %GRI80 (≤55, >55-80, >80%), and %wound red index 80 (≤25, >25-50, >50%). In the linear mixed model, higher classes for all GRI parameters showed significantly greater relative improvement in overall wound severity during the 3 weeks after adjustment for patient characteristics and wound locations. Assessment of granulation tissue color by digital image analysis will be useful as an objective monitoring tool for granulation tissue quality or surrogate outcomes of pressure ulcer healing. © 2012 by the Wound Healing Society.

Effects of wave shape on sheet flow sediment transport

USGS Publications Warehouse

Hsu, T.-J.; Hanes, D.M.

2004-01-01

A two-phase model is implemented to study the effects of wave shape on the transport of coarse-grained sediment in the sheet flow regime. The model is based on balance equations for the average mass, momentum, and fluctuation energy for both the fluid and sediment phases. Model simulations indicate that the responses of the sheet flow, such as the velocity profiles, the instantaneous bed shear stress, the sediment flux, and the total amount of the mobilized sediment, cannot be fully parameterized by quasi-steady free-stream velocity and may be correlated with the magnitude of local horizontal pressure gradient (or free-stream acceleration). A net sediment flux in the direction of wave advance is obtained for both skewed and saw-tooth wave shapes typical of shoaled and breaking waves. The model further suggests that at critical values of the horizontal pressure gradient, there is a failure event within the bed that mobilizes more sediment into the mobile sheet and enhances the sediment flux. Preliminary attempts to parameterize the total bed shear stress and the total sediment flux appear promising. Copyright 2004 by the American Geophysical Union.

Prediction of transfer among multiple states of blood pressure based on Markov model: an 18-year cohort study.

PubMed

Wang, Yunfeng; Ma, Zhimin; Xu, Chaonan; Wang, ZiKun; Yang, Xinghua

2018-05-15

This study aimed to identify the rules of transition between normotension, prehypertension and hypertension states and to establish a prediction model for the incidence of prehypertension and hypertension. Data from the China Health and Nutrition Survey from 1991 to 2009 were used as training data to develop the model. Data of the year 2011 were used for model validation. The multistate Markov model was developed using the msm package in R software. A total of 5265 participants were included at baseline, with an average follow-up of 8.05 ± 5.27 years and 17 640 observations. The ratio of men to women was 1 : 1.17, and the mean age was 37.54 ± 13.80 years. Within 10 years, in men, from normotension, the average probability to prehypertension and hypertension are 34.5 and 35.25%, respectively; from prehypertension, the average probability of recovering to normotension and developing to hypertension are 17.78 and 43.85%, respectively. In women, the average probabilities are 27.49, 28.09, 29.11 and 39.05%. Fat consumption increasing was found to be a protective factor, with 4.5% lower rate of transferring from normotension to prehypertension for a quarter percentage increasing. The model showed a very good prediction ability within 10 years and provided good prediction of blood pressure in the 2011 cohort (χ = 0.781, P = 0.676). The multistate Markov model can be a useful tool to identify the rules of transition among multiple states of blood pressure and predict well prevalence of the normotension, prehypertension and hypertension in cohort populations.

Pressure dependence of effective Coulomb interaction parameters in BaFe2As2 by first-principle calculation

NASA Astrophysics Data System (ADS)

Aghajani, M.; Hadipour, H.; Akhavan, M.

2018-05-01

Pressure dependence of the onsite Coulomb interactions of the BaFe2As2 has been studied by employing the constrained random phase approximation within first-principle calculations. Analyzing total and projected density of states, a pseudogap is found for dxy band at the energy roughly 0.25 eV higher than the Fermi level. Also, by applying pressure the spectral weight of the dxy orbital vanishes while other orbitals remain metallic. The different screening channels, as discussed in four different models, affect significantly on the Hubbard U while the Hund J remains almost unchanged. The average onsite bare and partially and fully screened Coulomb interactions increase with different rates upon compression. These different rates can be explained by competition between the electronic screening and reduction of bond lengths.

Vortex Generators in a Streamline-Traced, External-Compression Supersonic Inlet

NASA Technical Reports Server (NTRS)

Baydar, Ezgihan; Lu, Frank K.; Slater, John W.; Trefny, Charles J.

2017-01-01

Vortex generators within a streamline-traced, external-compression supersonic inlet for Mach 1.66 were investigated to determine their ability to increase total pressure recovery and reduce total pressure distortion. The vortex generators studied were rectangular vanes arranged in counter-rotating and co-rotating arrays. The vane geometric factors of interest included height, length, spacing, angle-of-incidence, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated numerically through the solution of the steady-state, Reynolds-averaged Navier-Stokes equations on multi-block, structured grids using the Wind-US flow solver. The vanes were simulated using a vortex generator model. The inlet performance was characterized by the inlet total pressure recovery and the radial and circumferential total pressure distortion indices at the engine face. Design of experiments and statistical analysis methods were applied to quantify the effect of the geometric factors of the vanes and search for optimal vane arrays. Co-rotating vane arrays with negative angles-of-incidence positioned on the supersonic diffuser were effective in sweeping low-momentum flow from the top toward the sides of the subsonic diffuser. This distributed the low-momentum flow more evenly about the circumference of the subsonic diffuser and reduced distortion. Co-rotating vane arrays with negative angles-of-incidence or counter-rotating vane arrays positioned downstream of the terminal shock were effective in mixing higher-momentum flow with lower-momentum flow to increase recovery and decrease distortion. A strategy of combining a co-rotating vane array on the supersonic diffuser with a counter-rotating vane array on the subsonic diffuser was effective in increasing recovery and reducing distortion.

Enthalpy Distributions of Arc Jet Flow Based on Measured Laser Induced Fluorescence, Heat Flux and Stagnation Pressure Distributions

NASA Technical Reports Server (NTRS)

Suess, Leonard E.; Milhoan, James D.; Oelke, Lance; Godfrey, Dennis; Larin, Maksim Y.; Scott, Carl D.; Grinstead, Jay H.; DelPapa, Steven

2011-01-01

The centerline total enthalpy of arc jet flow is determined using laser induced fluorescence of oxygen and nitrogen atoms. Each component of the energy, kinetic, thermal, and chemical can be determined from LIF measurements. Additionally, enthalpy distributions are inferred from heat flux and pressure probe distribution measurements using an engineering formula. Average enthalpies are determined by integration over the radius of the jet flow, assuming constant mass flux and a mass flux distribution estimated from computational fluid dynamics calculations at similar arc jet conditions. The trends show favorable agreement, but there is an uncertainty that relates to the multiple individual measurements and assumptions inherent in LIF measurements.

Invasive blood pressure recording comparing nursing charts with an electronic monitor: a technical report.

PubMed

Wong, Benjamin T; Glassford, Neil J; Bion, Victoria; Chai, Syn Y; Bellomo, Rinaldo

2014-03-01

Blood pressure management (assessed using nursing charts) in the early phase of septic shock may have an effect on renal outcomes. Assessment of mean arterial pressure (MAP) values as recorded on nursing charts may be inaccurate. To determine the difference between hourly blood pressure values as recorded on the nursing charts and hourly average blood pressure values over the corresponding period obtained electronically from the bedside monitor. We studied 20 patients with shock requiring vasopressor support and invasive blood pressure monitoring. Hourly blood pressure measurements were recorded on the nursing charts over a 12-hour period. Blood pressure values recorded every 10 minutes were downloaded from electronic patient monitors over the corresponding period. The hourly average of the 10-minute blood pressure values was compared with the measurements recorded on the nursing charts. We assessed 240 chart readings and 1440 electronic recordings. Average chart MAP was 72.54 mmHg and average electronic monitor MAP was 71.54 mmHg. MAP data from the two sources showed a strong correlation (ρ0.71, P < 0.005). Bland-Altman assessment revealed acceptable agreement, with a mean bias of 1mmHg and 95% limits of agreement of -11.76 mmHg and 13.76 mmHg. Using average data over 6 hours, 95% limits of agreement narrowed to -6.79mmHg and 8.79mmHg. With multiple measurements over time, mean blood pressure as recorded on nursing charts reasonably approximates mean blood pressure recorded on the monitor.

Petrologic Constraints on Magma Plumbing Systems Beneath Hawaiian Volcanoes

NASA Astrophysics Data System (ADS)

Li, Y.; Peterman, K. J.; Scott, J. L.; Barton, M.

2016-12-01

We have calculated the pressures of partial crystalliztion of basaltic magmas from Hawaii using a petrological method. A total of 1576 major oxide analyses of glasses from four volcanoes (Kilauea and the Puna Ridge, Loihi, Mauna Loa, and Mauna Kea, on the Big Island) were compiled and used as input data. Glasses represent quenched liquid compositions and are ideal for calculation of pressures of partial crystallization. The results were filtered to exclude samples that yielded unrealistic high errors associated with the calculated pressure or negative value of pressure, and to exclude samples with non-basaltic compositions. Calculated pressures were converted to depths of partial crystallization. The majority (68.2%) of pressures for the shield-stage subaerial volcanoes Kilauea, Mauna Loa, and Mauna Kea, fall in the range 0-140 MPa, corresponding to depths of 0-5 km. Glasses from the Puna Ridge yield pressures ranging from 18 to 126 MPa and are virtually identical to pressures determined from glasses from Kilauea (0 to 129 MPa). These results are consistent with the presence of magma reservoirs at depths of 0-5 km beneath the large shield volcanoes. The inferred depth of the magma reservoir beneath the summit of Kilauea (average = 1.8 km, maximum = 5 km) agrees extremely well with depths ( 2-6 km) estimated from seismic studies. The results for Kilauea and Mauna Kea indicate that significant partial crystallization also occurs beneath the summit reservoirs at depths up to 11 km. These results are consistent with seismic evidence for the presence of a magma reservoir at 8-11 km beneath Kilauea at the base of the volcanic pile. The results for Loihi indicate crystallization at higher average pressures (100-400 MPa) and depths (3-14 km) than the large shield volcanoes, suggesting that the plumbing system is not yet fully developed, and that the Hawaiian volcanic plumbing systems evolve over time.

Inferior gluteal artery perforator flap: a viable alternative for ischial pressure sores.

PubMed

Kim, Young Seok; Lew, Dae Hyun; Roh, Tai Suk; Yoo, Won Min; Lee, Won Jai; Tark, Kwan Chul

2009-10-01

The ischial area is by far the most common site for pressure sores in wheelchair-bound paraplegic patients, because most of the pressure of the body is exerted on this area in the seated position. Even after a series of successful pressure sore treatments, the site is very prone to relapse from the simplest everyday tasks. Therefore, it is crucial to preserve the main pedicle during primary surgery. Several surgical procedures, such as myocutaneous flap and perforator flap, have been introduced for the treatment of pressure sores. During a 4-year time period at our institute, we found favourable clinical results using the inferior gluteal artery perforator (IGAP) procedure for ischial sore treatment. A total of 23 patients (20 males and three females) received IGAP flap surgery in our hospital from January 2003 to January 2007. Surgery was performed on the same site again in 10 (43%) patients who had originally relapsed after undergoing the conventional method of pressure sore surgery. The average age of patients was 47.4 years (range 26-71 years). Most of the patients were paraplegic (16 cases, 70%) and others were either quadriplegic (four cases, 17%) or ambulatory (three cases, 13%). Based on hospital records and clinical photographs, we attempted to assess the feasibility and practicability of the IGAP flap procedure through comparative analysis of several parameters including the size of the defective area, treatment modalities, relapses, complications, and postoperative treatments. The average follow-up duration for 23 subjects was 25.4 months (range 5-42 months). All flaps survived without major complications. Partial flap necrosis developed in one case but secondary healing was achieved and the final outcome was not impaired. Most of the cases healed well during the follow-up period. Postoperative complications such as wound dehiscence and fistula developed in some subjects, but all healed well with a secondary treatment. A total of five cases relapsed after surgery due to tissue deficit and these were treated with bursectomy and muscle transposition flap to fill the dead space. We propose that the IGAP flap should be considered a viable alternative to other methods of ischial pressure sore surgery owing to its many advantages, which include the ability to preserve peripheral muscle tissue, the variability of flap designs, relatively good durability, and the low donor site morbidity rate.

Effect of skim milk treated with high hydrostatic pressure on permeate flux and fouling during ultrafiltration.

PubMed

Leu, Mathilde; Marciniak, Alice; Chamberland, Julien; Pouliot, Yves; Bazinet, Laurent; Doyen, Alain

2017-09-01

Ultrafiltration (UF) is largely used in the dairy industry to generate milk and whey protein concentrate for standardization of milk or production of dairy ingredients. Recently, it was demonstrated that high hydrostatic pressure (HHP) extended the shelf life of milk and improved rennet coagulation and cheese yield. Pressurization also modified casein micelle size distribution and promoted aggregation of whey proteins. These changes are likely to affect UF performance. Consequently, this study determined the effect of skim milk pressurization (300 and 600 MPa, 5 min) on UF performance in terms of permeate flux decline and fouling. The effect of HHP on milk proteins was first studied and UF was performed in total recycle mode at different transmembrane pressures to determine optimal UF operational parameters and to evaluate the effect of pressurization on critical and limiting fluxes. Ultrafiltration was also performed in concentration mode at a transmembrane pressure of 345 kPa for 130 or 140 min to evaluate the decline of permeate flux and to determine fouling resistances. It was observed that average casein micelle size decreased by 32 and 38%, whereas β-lactoglobulin denaturation reached 30 and 70% at 300 and 600 MPa, respectively. These results were directly related to UF performance because initial permeate fluxes in total recycle mode decreased by 25% at 300 and 600 MPa compared with nonpressurized milk, critical flux, and limiting flux, which were lower during UF of milk treated with HHP. During UF in concentration mode, initial permeate fluxes were 30% lower at 300 and 600 MPa compared with the control, but the total flux decline was higher for nonpressurized milk (62%) compared with pressure-treated milk (30%). Fouling resistances were similar, whatever the treatment, except at 600 MPa where irreversible fouling was higher. Characterization of the fouling layer showed that caseins and β-lactoglobulin were mainly involved in membrane fouling after UF of pressure-treated milk. Our results demonstrate that HHP treatment of skim milk drastically decreased UF performance. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Suicide and meteorological factors in São Paulo, Brazil, 1996-2011: a time series analysis.

PubMed

Bando, Daniel H; Teng, Chei T; Volpe, Fernando M; Masi, Eduardo de; Pereira, Luiz A; Braga, Alfésio L

2017-01-01

Considering the scarcity of reports from intertropical latitudes and the Southern Hemisphere, we aimed to examine the association between meteorological factors and suicide in São Paulo. Weekly suicide records stratified by sex were gathered. Weekly averages for minimum, mean, and maximum temperature (°C), insolation (hours), irradiation (MJ/m2), relative humidity (%), atmospheric pressure (mmHg), and rainfall (mm) were computed. The time structures of explanatory variables were modeled by polynomial distributed lag applied to the generalized additive model. The model controlled for long-term trends and selected meteorological factors. The total number of suicides was 6,600 (5,073 for men), an average of 6.7 suicides per week (8.7 for men and 2.0 for women). For overall suicides and among men, effects were predominantly acute and statistically significant only at lag 0. Weekly average minimum temperature had the greatest effect on suicide; there was a 2.28% increase (95%CI 0.90-3.69) in total suicides and a 2.37% increase (95%CI 0.82-3.96) among male suicides with each 1 °C increase. This study suggests that an increase in weekly average minimum temperature has a short-term effect on suicide in São Paulo.

Numerical Investigation of Vortex Generator Flow Control for External-Compression Supersonic Inlets

NASA Astrophysics Data System (ADS)

Baydar, Ezgihan

Vortex generators (VGs) within external-compression supersonic inlets for Mach 1.6 were investigated to determine their ability to increase total pressure recovery and reduce total pressure distortion. Ramp and vane-type VGs were studied. The geometric factors of interest included height, length, spacing, angle-of-incidence, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated numerically through the solution of the steady-state, Reynolds-averaged Navier-Stokes equations on multi-block, structured grids using the Wind-US flow solver. The inlet performance was characterized by the inlet total pressure recovery and the radial and circumferential total pressure distortion indices at the engine face. Previous research of downstream VGs in the low-boom supersonic inlet demonstrated improvement in radial distortion up to 24% while my work on external-compression supersonic inlets improved radial distortion up to 86%, which is significant. The design of experiments and statistical analysis methods were applied to quantify the effect of the geometric factors of VGs and search for optimal VG arrays. From the analysis, VG angle-of-incidence and VG height were the most influential factors in increasing total pressure recovery and reducing distortion. The study on the two-dimensional external-compression inlet determined which passive flow control devices, such as counter-rotating vanes or ramps, reduce high distortion levels and improve the health of the boundary layer, relative to the baseline. Downstream vanes demonstrate up to 21% improvement in boundary layer health and 86% improvement in radial distortion. Upstream vanes demonstrated up to 3% improvement in boundary layer health and 9% improvement in radial distortion. Ramps showed no improvement in boundary layer health and radial distortion. Micro-VGs were preferred for their reduced viscous drag and improvement in total pressure recovery at the AIP. Although traditional VGs energize the flow with stronger vortex structures compared to micro-VGs, the AIP is affected with overwhelming amounts of reduced and enhanced flow regions. In summary, vanes are exceptional in reducing radial distortion and improving the health of the boundary layer compared to the ramps. In the study of the STEX inlet, vane-type vortex generators were the preferred devices for boundary layer flow control. In the supersonic diffuser, co-rotating vane arrays and counter-rotating vane arrays did not show improvement. In the subsonic diffuser, co-rotating vane arrays with negative angles-of-incidence and counter-rotating vane arrays were exceptional in reducing radial distortion and improving total pressure recovery. Downstream co-rotating vanes demonstrated up to 41% improvement in radial distortion whereas downstream counter-rotating vanes demonstrated up to 73% improvement. For downstream counter-rotating vanes, a polynomial trend between VG height and radial distortion indicate that increasing VG height improves inlet distortion. In summary, downstream vanes are exceptional in improving total pressure recovery compared to upstream vanes.

Ambulatory Blood Pressure Monitoring in Clinical Practice: A Review

PubMed Central

Viera, Anthony J.; Shimbo, Daichi

2016-01-01

Ambulatory blood pressure monitoring offers the ability to collect blood pressure readings several times an hour across a 24-hour period. Ambulatory blood pressure monitoring facilitates the identification of white-coat hypertension, the phenomenon whereby certain individuals who are not on antihypertensive medication show elevated blood pressure in a clinical setting but show non-elevated blood pressure averages when assessed by ambulatory blood pressure monitoring. Additionally, readings can be segmented into time windows of particular interest, e.g., mean daytime and nighttime values. During sleep, blood pressure typically decreases, or dips, such that mean sleep blood pressure is lower than mean awake blood pressure. A non-dipping pattern and nocturnal hypertension are strongly associated with increased cardiovascular morbidity and mortality. Approximately 70% of individuals dip ≥10% at night, while 30% have non-dipping patterns, when blood pressure remains similar to daytime average, or occasionally rises above daytime average. The various blood pressure categorizations afforded by ambulatory blood pressure monitoring are valuable for clinical management of high blood pressure since they increase accuracy for diagnosis and the prediction of cardiovascular risk. PMID:25107387

40 CFR Table 2 to Subpart Kkkkk of... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Maintain the average scrubber pressure drop for each 3-hour block period at or above the average pressure drop established during the performance test; andb. Maintain the average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test...

Past epochs of significantly higher pressure atmospheres on Pluto

NASA Astrophysics Data System (ADS)

Stern, S. A.; Binzel, R. P.; Earle, A. M.; Singer, K. N.; Young, L. A.; Weaver, H. A.; Olkin, C. B.; Ennico, K.; Moore, J. M.; McKinnon, W. B.; Spencer, J. R.; New Horizons Geology; Geophysics; Atmospheres Teams

2017-05-01

Pluto is known to have undergone thousands of cycles of obliquity change and polar precession. These variations have a large and corresponding impact on the total average solar insolation reaching various places on Pluto's surface as a function of time. Such changes could produce dramatic increases in surface pressure and may explain certain features observed by New Horizons on Pluto's surface, including some that indicate the possibility of surface paleo-liquids. This paper is the first to discuss multiple lines of geomorphological evidence consistent with higher pressure epochs in Pluto's geologic past, and it also the first to provide a mechanism for potentially producing the requisite high pressure conditions needed for an environment that could support liquids on Pluto. The presence of such liquids and such conditions, if borne out by future work, would fundamentally affect our view of Pluto's past climate, volatile transport, and geological evolution. This paper motivates future, more detailed climate modeling and geologic interpretation efforts in this area.

A description of intraoperative ventilator management in patients with acute lung injury and the use of lung protective ventilation strategies.

PubMed

Blum, James M; Maile, Michael; Park, Pauline K; Morris, Michelle; Jewell, Elizabeth; Dechert, Ronald; Rosenberg, Andrew L

2011-07-01

The incidence of acute lung injury (ALI) in hypoxic patients undergoing surgery is currently unknown. Previous studies have identified lung protective ventilation strategies that are beneficial in the treatment of ALI. The authors sought to determine the incidence and examine the use of lung protective ventilation strategies in patients receiving anesthetics with a known history of ALI. The ventilation parameters that were used in all patients were reviewed, with an average preoperative PaO₂/Fio₂ [corrected] ratio of ≤ 300 between January 1, 2005 and July 1, 2009. This dataset was then merged with a dataset of patients screened for ALI. The median tidal volume, positive end-expiratory pressure, peak inspiratory pressures, fraction inhaled oxygen, oxygen saturation, and tidal volumes were compared between groups. A total of 1,286 patients met criteria for inclusion; 242 had a diagnosis of ALI preoperatively. Comparison of patients with ALI versus those without ALI found statistically yet clinically insignificant differences between the ventilation strategies between the groups in peak inspiratory pressures and positive end-expiratory pressure but no other category. The tidal volumes in cc/kg predicted body weight were approximately 8.7 in both groups. Peak inspiratory pressures were found to be 27.87 cm H₂O on average in the non-ALI group and 29.2 in the ALI group. Similar ventilation strategies are used between patients with ALI and those without ALI. These findings suggest that anesthesiologists are not using lung protective ventilation strategies when ventilating patients with low PaO₂/Fio₂ [corrected] ratios and ALI, and instead are treating hypoxia and ALI with higher concentrations of oxygen and peak pressures.

Influence of Different Patellofemoral Design Variations Based on Genesis II Total Knee Endoprosthesis on Patellofemoral Pressure and Kinematics.

PubMed

Leichtle, Ulf G; Lange, Barbara; Herzog, Yvonne; Schnauffer, Peter; Leichtle, Carmen I; Wülker, Nikolaus; Lorenz, Andrea

2017-01-01

In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt ( p < 0.05 for 35°-80° flexion) and translation of the patella ( p < 0.045 for 20°-65° and 75°-90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA.

Static Feed Water Electrolysis Subsystem Testing and Component Development

NASA Technical Reports Server (NTRS)

Koszenski, E. P.; Schubert, F. H.; Burke, K. A.

1983-01-01

A program was carried out to develop and test advanced electrochemical cells/modules and critical electromechanical components for a static feed (alkaline electrolyte) water electrolysis oxygen generation subsystem. The accomplishments were refurbishment of a previously developed subsystem and successful demonstration for a total of 2980 hours of normal operation; achievement of sustained one-person level oxygen generation performance with state-of-the-art cell voltages averaging 1.61 V at 191 ASF for an operating temperature of 128F (equivalent to 1.51V when normalized to 180F); endurance testing and demonstration of reliable performance of the three-fluid pressure controller for 8650 hours; design and development of a fluid control assembly for this subsystem and demonstration of its performance; development and demonstration at the single cell and module levels of a unitized core composite cell that provides expanded differential pressure tolerance capability; fabrication and evaluation of a feed water electrolyte elimination five-cell module; and successful demonstration of an electrolysis module pressurization technique that can be used in place of nitrogen gas during the standby mode of operation to maintain system pressure and differential pressures.

Validation of the Grandway MD2301 digital automatic blood pressure monitor according to the European Society of Hypertension International Protocol.

PubMed

Chen, Wan; Zeng, Zhao-Lin; Bing, Sen; Li, Lin-Yi; Wang, Rui; Wan, Yi

2016-08-01

The aim of the present study was to validate the Grandway MD2301 digital automatic blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. The ESH-IP revision 2010 for the validation of blood pressure-measuring devices in adults was followed precisely. Systolic and diastolic blood pressure (SBP and DBP, respectively) were measured sequentially in 33 adult patients and compared with a standard mercury sphygmomanometer (two observers). A total of 99 comparison pairs were obtained. The device produced 78, 95 and 99 measurements within 5, 10, and 15 mmHg for SBP and 83, 96, and 99 for DBP, respectively. The average device-observer difference was -1.81±4.22 mmHg for SBP and -0.15±3.93 mmHg for DBP. All of the data were within the standards requirements to pass the testing. The Grandway MD2301 digital automatic blood pressure monitor meets the standards of the ESH-IP revision 2010 and can be recommended for self/home measurement in the general population.

Conservative-variable average states for equilibrium gas multi-dimensional fluxes

NASA Technical Reports Server (NTRS)

Iannelli, G. S.

1992-01-01

Modern split component evaluations of the flux vector Jacobians are thoroughly analyzed for equilibrium-gas average-state determinations. It is shown that all such derivations satisfy a fundamental eigenvalue consistency theorem. A conservative-variable average state is then developed for arbitrary equilibrium-gas equations of state and curvilinear-coordinate fluxes. Original expressions for eigenvalues, sound speed, Mach number, and eigenvectors are then determined for a general average Jacobian, and it is shown that the average eigenvalues, Mach number, and eigenvectors may not coincide with their classical pointwise counterparts. A general equilibrium-gas equation of state is then discussed for conservative-variable computational fluid dynamics (CFD) Euler formulations. The associated derivations lead to unique compatibility relations that constrain the pressure Jacobian derivatives. Thereafter, alternative forms for the pressure variation and average sound speed are developed in terms of two average pressure Jacobian derivatives. Significantly, no additional degree of freedom exists in the determination of these two average partial derivatives of pressure. Therefore, they are simultaneously computed exactly without any auxiliary relation, hence without any geometric solution projection or arbitrary scale factors. Several alternative formulations are then compared and key differences highlighted with emphasis on the determination of the pressure variation and average sound speed. The relevant underlying assumptions are identified, including some subtle approximations that are inherently employed in published average-state procedures. Finally, a representative test case is discussed for which an intrinsically exact average state is determined. This exact state is then compared with the predictions of recent methods, and their inherent approximations are appropriately quantified.

Effects of Periodic Unsteady Wake Flow and Pressure Gradient on Boundary Layer Transition Along the Concave Surface of a Curved Plate. Part 3

NASA Technical Reports Server (NTRS)

Schobeiri, M. T.; Radke, R. E.

1996-01-01

Boundary layer transition and development on a turbomachinery blade is subjected to highly periodic unsteady turbulent flow, pressure gradient in longitudinal as well as lateral direction, and surface curvature. To study the effects of periodic unsteady wakes on the concave surface of a turbine blade, a curved plate was utilized. On the concave surface of this plate, detailed experimental investigations were carried out under zero and negative pressure gradient. The measurements were performed in an unsteady flow research facility using a rotating cascade of rods positioned upstream of the curved plate. Boundary layer measurements using a hot-wire probe were analyzed by the ensemble-averaging technique. The results presented in the temporal-spatial domain display the transition and further development of the boundary layer, specifically the ensemble-averaged velocity and turbulence intensity. As the results show, the turbulent patches generated by the wakes have different leading and trailing edge velocities and merge with the boundary layer resulting in a strong deformation and generation of a high turbulence intensity core. After the turbulent patch has totally penetrated into the boundary layer, pronounced becalmed regions were formed behind the turbulent patch and were extended far beyond the point they would occur in the corresponding undisturbed steady boundary layer.

The erosion/corrosion of small superalloy turbine rotors operating in the effluent of a PFB coal combustor

NASA Technical Reports Server (NTRS)

Zellars, G. R.; Benfold, S. M.; Rowe, A. P.; Lowell, C. E.

1979-01-01

Superalloy turbine rotors in a single stage turbine with 6 percent partial admittance were operated in the effluent of a pressurized fluidized bed coal combustor for up to 164 hours. Total mass flow was 300 kg/hr and average particulate loadings ranged from 600 to 2800 ppm for several coal/sorbent combinations. A 5.5 atm turbine inlet gas pressure and inlet gas temperatures from 700 to 800 C yielded absolute gas velocities at the stator exit of about 500 m/s. The angular rotation speed (40,000 rpm) of the six inch diameter rotors was equivalent to a tip speed of about 300 m/s, and average gas velocities relative to the rotating surface ranged from 260 to 330 m/s at mean radius. The rotor erosion pattern reflects heavy particle separation with severe (5 to 500 cm/yr) erosion at the leading edge, pressure side center, and suction side trailing edge at the tip. The erosion distribution pattern provides a spectrum of erosion/oxidation/deposition as a function of blade position. This spectrum includes enhanced oxidation (10 to 100 x air), mixed oxides in exposed depletion zones, sulfur rich oxides in deposition zones, and rugged areas of erosive oxide removal.

Aero-thermal optimization of film cooling flow parameters on the suction surface of a high pressure turbine blade

NASA Astrophysics Data System (ADS)

El Ayoubi, Carole; Hassan, Ibrahim; Ghaly, Wahid

2012-11-01

This paper aims to optimize film coolant flow parameters on the suction surface of a high-pressure gas turbine blade in order to obtain an optimum compromise between a superior cooling performance and a minimum aerodynamic penalty. An optimization algorithm coupled with three-dimensional Reynolds-averaged Navier Stokes analysis is used to determine the optimum film cooling configuration. The VKI blade with two staggered rows of axially oriented, conically flared, film cooling holes on its suction surface is considered. Two design variables are selected; the coolant to mainstream temperature ratio and total pressure ratio. The optimization objective consists of maximizing the spatially averaged film cooling effectiveness and minimizing the aerodynamic penalty produced by film cooling. The effect of varying the coolant flow parameters on the film cooling effectiveness and the aerodynamic loss is analyzed using an optimization method and three dimensional steady CFD simulations. The optimization process consists of a genetic algorithm and a response surface approximation of the artificial neural network type to provide low-fidelity predictions of the objective function. The CFD simulations are performed using the commercial software CFX. The numerical predictions of the aero-thermal performance is validated against a well-established experimental database.

Effects of flow separation and cove leakage on pressure and heat-transfer distributions along a wing-cove-elevon configuration at Mach 6.9. [Langley 8-ft high temperature tunnel test

NASA Technical Reports Server (NTRS)

Deveikis, W. D.

1983-01-01

External and internal pressure and cold-wall heating-rate distributions were obtained in hypersonic flow on a full-scale heat-sink representation of the space shuttle orbiter wing-elevon-cove configuration in an effort to define effects of flow separation on cove aerothermal environment as a function of cove seal leak area, ramp angle, and free-stream unit Reynolds number. Average free-stream Mach number from all tests was 6.9; average total temperature from all tests was 3360 R; free-stream dynamic pressure ranged from about 2 to 9 psi; and wing angle of attack was 5 deg (flow compression). For transitional and turbulent flow separation, increasing cove leakage progressively increased heating rates in the cove. When ingested mass flow was sufficient to force large reductions in extent of separation, increasing cove leakage reduced heating rates in the cove to those for laminar attached flow. Cove heating-rate distributions calculated with a method that assumed laminar developing channel flow agreed with experimentally obtained distributions within root-mean-square differences that varied between 11 and 36 percent where cove walls were parallel for leak areas of 50 and 100 percent.

Estimating outflow facility through pressure dependent pathways of the human eye

PubMed Central

Gardiner, Bruce S.

2017-01-01

We develop and test a new theory for pressure dependent outflow from the eye. The theory comprises three main parameters: (i) a constant hydraulic conductivity, (ii) an exponential decay constant and (iii) a no-flow intraocular pressure, from which the total pressure dependent outflow, average outflow facilities and local outflow facilities for the whole eye may be evaluated. We use a new notation to specify precisely the meaning of model parameters and so model outputs. Drawing on a range of published data, we apply the theory to animal eyes, enucleated eyes and in vivo human eyes, and demonstrate how to evaluate model parameters. It is shown that the theory can fit high quality experimental data remarkably well. The new theory predicts that outflow facilities and total pressure dependent outflow for the whole eye are more than twice as large as estimates based on the Goldman equation and fluorometric analysis of anterior aqueous outflow. It appears likely that this discrepancy can be largely explained by pseudofacility and aqueous flow through the retinal pigmented epithelium, while any residual discrepancy may be due to pathological processes in aged eyes. The model predicts that if the hydraulic conductivity is too small, or the exponential decay constant is too large, then intraocular eye pressure may become unstable when subjected to normal circadian changes in aqueous production. The model also predicts relationships between variables that may be helpful when planning future experiments, and the model generates many novel testable hypotheses. With additional research, the analysis described here may find application in the differential diagnosis, prognosis and monitoring of glaucoma. PMID:29261696

Dependence of N-polar GaN rod morphology on growth parameters during selective area growth by MOVPE

NASA Astrophysics Data System (ADS)

Li, Shunfeng; Wang, Xue; Mohajerani, Matin Sadat; Fündling, Sönke; Erenburg, Milena; Wei, Jiandong; Wehmann, Hergo-Heinrich; Waag, Andreas; Mandl, Martin; Bergbauer, Werner; Strassburg, Martin

2013-02-01

Selective area growth of GaN rods by metalorganic vapor phase epitaxy has attracted great interest due to its novel applications in optoelectronic and photonics. In this work, we will present the dependence of GaN rod morphology on various growth parameters i.e. growth temperature, H2/N2 carrier gas concentration, V/III ratio, total carrier gas flow and reactor pressure. It is found that higher growth temperature helps to increase the aspect ratio of the rods, but reduces the height homogeneity. Furthermore, H2/N2 carrier gas concentration is found to be a critical factor to obtain vertical rod growth. Pure nitrogen carrier gas leads to irregular growth of GaN structure, while an increase of hydrogen carrier gas results in vertical GaN rod growth. Higher hydrogen carrier gas concentration also reduces the diameter and enhances the aspect of the GaN rods. Besides, increase of V/III ratio causes reduction of the aspect ratio of N-polar GaN rods, which could be explained by the relatively lower growth rate on (000-1) N-polar top surface when supplying more ammonia. In addition, an increase of the total carrier gas flow leads to a decrease in the diameter and the average volume of GaN rods. These phenomena are tentatively explained by the change of partial pressure of the source materials and boundary layer thickness in the reactor. Finally, it is shown that the average volume of the N-polar GaN rods keeps a similar value for a reactor pressure PR of 66 and 125 mbar, while an incomplete filling of the pattern opening is observed with PR of 250 mbar. Room temperature photoluminescence spectrum of the rods is also briefly discussed.

Early in vivo experience with the pediatric continuous-flow total artificial heart.

PubMed

Karimov, Jamshid H; Horvath, David J; Byram, Nicole; Sunagawa, Gengo; Kuban, Barry D; Gao, Shengqiang; Dessoffy, Raymond; Fukamachi, Kiyotaka

2018-03-30

Heart transplantation in infants and children is an accepted therapy for end-stage heart failure, but donor organ availability is low and always uncertain. Mechanical circulatory support is another standard option, but there is a lack of intracorporeal devices due to size and functional range. The purpose of this study was to evaluate the in vivo performance of our initial prototype of a pediatric continuous-flow total artificial heart (P-CFTAH), comprising a dual pump with one motor and one rotating assembly, supported by a hydrodynamic bearing. In acute studies, the P-CFTAH was implanted in 4 lambs (average weight: 28.7 ± 2.3 kg) via a median sternotomy under cardiopulmonary bypass. Pulmonary and systemic pump performance parameters were recorded. The experiments showed good anatomical fit and easy implantation, with an average aortic cross-clamp time of 98 ± 18 minutes. Baseline hemodynamics were stable in all 4 animals (pump speed: 3.4 ± 0.2 krpm; pump flow: 2.1 ± 0.9 liters/min; power: 3.0 ± 0.8 W; arterial pressure: 68 ± 10 mm Hg; left and right atrial pressures: 6 ± 1 mm Hg, for both). Any differences between left and right atrial pressures were maintained within the intended limit of ±5 mm Hg over a wide range of ratios of systemic-to-pulmonary vascular resistance (0.7 to 12), with and without pump-speed modulation. Pump-speed modulation was successfully performed to create arterial pulsation. This initial P-CFTAH prototype met the proposed requirements for self-regulation, performance, and pulse modulation. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

A Simplified Model for Detonation Based Pressure-Gain Combustors

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

2010-01-01

A time-dependent model is presented which simulates the essential physics of a detonative or otherwise constant volume, pressure-gain combustor for gas turbine applications. The model utilizes simple, global thermodynamic relations to determine an assumed instantaneous and uniform post-combustion state in one of many envisioned tubes comprising the device. A simple, second order, non-upwinding computational fluid dynamic algorithm is then used to compute the (continuous) flowfield properties during the blowdown and refill stages of the periodic cycle which each tube undergoes. The exhausted flow is averaged to provide mixed total pressure and enthalpy which may be used as a cycle performance metric for benefits analysis. The simplicity of the model allows for nearly instantaneous results when implemented on a personal computer. The results compare favorably with higher resolution numerical codes which are more difficult to configure, and more time consuming to operate.

Computer code for preliminary sizing analysis of axial-flow turbines

NASA Technical Reports Server (NTRS)

Glassman, Arthur J.

1992-01-01

This mean diameter flow analysis uses a stage average velocity diagram as the basis for the computational efficiency. Input design requirements include power or pressure ratio, flow rate, temperature, pressure, and rotative speed. Turbine designs are generated for any specified number of stages and for any of three types of velocity diagrams (symmetrical, zero exit swirl, or impulse) or for any specified stage swirl split. Exit turning vanes can be included in the design. The program output includes inlet and exit annulus dimensions, exit temperature and pressure, total and static efficiencies, flow angles, and last stage absolute and relative Mach numbers. An analysis is presented along with a description of the computer program input and output with sample cases. The analysis and code presented herein are modifications of those described in NASA-TN-D-6702. These modifications improve modeling rigor and extend code applicability.

[Study on supercritical CO2 extraction of xiaoyaosan and its GC-MS fingerprint].

PubMed

Zuo, Ya-Mei; Tian, Jun-Sheng; Guo, Xiao-Qing; Zhou, Yu-Zhi; Gao, Xiao-Xia; Qin, Xue-Mei

2014-02-01

To determine the optimum conditions of supercritical CO2 extraction of Xiaoyaosan, and establish its fingerprint by gas chromatography-mass spectrometry (GC-MS), the yield of extract were investigated, an orthogonal test was used to quantify the effects of extraction temperature, pressure, CO2 flow rate and time, and fingerprint analysis of different batches of extracts were by GC-MS. The optimal extraction conditions were determined as follows: extraction pressure 20 MPa, extraction temperature 50 degrees C, CO2 flow rate 25 kg x h(-1), extraction time 3 h, and average yield 2.2%. The GC-MS fingerprint was established and 27 common peaks were found, whose contents add up to 81.89% of the total peak area. Among them, 21 compounds were identified, accounting for 53.20% of the total extract. The extraction process is reasonable and favorable for industrial production. The GC-MS method is accurate, reliable, reproducible, and can be used for quality control of supercritical CO2 extract from Xiaoyaosan.

The Peculiar Behavior of Halo Coronal Mass Ejections in Solar Cycle 24

NASA Technical Reports Server (NTRS)

Gopalswamy, N.; Xie, H.; Akiyama, S.; Makela, P.; Yashiro, S.; Michalek, G.

2015-01-01

We report on the remarkable finding that the halo coronal mass ejections (CMEs) in cycle 24 are more abundant than in cycle 23, although the sunspot number in cycle 24 has dropped by approx. 40%. We also find that the distribution of halo-CME source locations is different in cycle 24: the longitude distribution of halos is much flatter with the number of halos originating at a central meridian distance greater than or equal to 60deg twice as large as that in cycle 23. On the other hand, the average speed and associated soft X-ray flare size are the same in both cycles, suggesting that the ambient medium into which the CMEs are ejected is significantly different. We suggest that both the higher abundance and larger central meridian longitudes of halo CMEs can be explained as a consequence of the diminished total pressure in the heliosphere in cycle 24. The reduced total pressure allows CMEs to expand more than usual making them appear as halos.

Diagnostics of ion beam generated from a Mather type plasma focus device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, L. K., E-mail: yapsl@um.edu.my; Ngoi, S. K., E-mail: yapsl@um.edu.my; Wong, C. S., E-mail: yapsl@um.edu.my

Diagnostics of ion beam emission from a 3 kJ Mather-type plasma focus device have been performed for deuterium discharge at low pressure regime. Deuterium plasma focus was found to be optimum at pressure of 0.2 mbar. The energy spectrum and total number of ions per shot from the pulsed ion beam are determined by using biased ion collectors, Faraday cup, and solid state nuclear track detector CR-39. Average energy of the ion beam obtained is about 60 keV. Total number of the ions has been determined to be in the order of 10{sup 11} per shot. Solid state nuclear trackmore » detectors (SSNTD) CR39 are employed to measure the particles at all angular direction from end on (0°) to side on (90°). Particle tracks are registered by SSNTD at 30° to 90°, except the one at the end-on 0°.« less

Selected meteorological data for an arid site near Beatty, Nye County, Nevada, calendar year 1988

USGS Publications Warehouse

Wood, James L.; Hill, Kevin J.; Andraski, Brian J.

1992-01-01

Selected meteorological data were collected at a study site adjacent to a low-level radioactive-waste burial facility near Beatty/ Nevada, for calendar year 1988. Data were collected in support of ongoing studies to estimate the potential for downward movement of radionuclides into the unsaturated sediments beneath waste-burial trenches at the facility. The data include air temperature, relative humidity, vapor pressure, incident solar radiation, windspeed, wind direction, and precipitation. The data are summarized in tables and graphs.Instrumentation used at the site is discussed. The discussion includes the type, reported accuracy, and mounting height of each sensor.In 1988, the average hourly air temperatures ranged from -10.2 degrees Celsius, in December, to 45.3 degrees Celsius, in July. Hourly averaged relative humidity ranged from about 12 percent to over 80 percent. Hourly vapor pressures ranged from 0.09 to 2.22 kilopascals. Daily values for maximum incident solar radiation ranged from 63 to 1,064 watts per square meter. Daily mean windspeed ranged from 1.2 to 7.8 meters per second. Monthly wind-direction patterns are shown in a series of diagrams in which wind direction is summed over 10-degree arcs from hourly averaged data. Total precipitation for 1988 was 104.5 millimeters, with over 70 percent occurring from January through May.

Management of pediatric postoperative chylothorax.

PubMed

Bond, S J; Guzzetta, P C; Snyder, M L; Randolph, J G

1993-09-01

Questions persist about the management of postoperative chylothorax in infants and children. Our experience with postoperative chylothorax over the most recent decade (1980 to 1990) has been reviewed. The type and amount of drainage, data from cardiac catheterization and echocardiography, operative decisions and details, and eventual outcomes have been cataloged. All patients were initially treated with total gut rest, with operation reserved for unabated drainage. Chylothorax developed postoperatively in 15 infants and 11 children (18 with a cardiac procedure and 8 with a noncardiac procedure). The average age was 3.1 years. Spontaneous cessation and cure occurred in 19 (73.1%) of these 26 patients, with an average drainage duration of 11.9 days (range, 4 to 30 days). Those for whom operation was chosen drained preoperatively for an average of 29.2 days (range, 25 to 40 days). There were no deaths in either group. Complications were lymphopenia (2 patients) and fungal sepsis (1 patient). The amount of drainage per day was not significantly different between patients treated operatively and those treated nonoperatively. Failure of nonoperative management was associated with venous hypertension from increased right-sided cardiac pressures or central venous thrombosis (p < 0.05, Fisher's exact test). Presumably this increased pressure is transmitted to the lymphatic system. These patients should be identified early and considered for thoracic duct suture or pleuroperitoneal shunting.

Radial and local time structure of the Saturnian ring current, revealed by Cassini

NASA Astrophysics Data System (ADS)

Sergis, N.; Jackman, C. M.; Thomsen, M. F.; Krimigis, S. M.; Mitchell, D. G.; Hamilton, D. C.; Dougherty, M. K.; Krupp, N.; Wilson, R. J.

2017-02-01

We analyze particle and magnetic field data obtained between July 2004 and December 2013 in the equatorial magnetosphere of Saturn, by the Cassini spacecraft. The radial and local time distribution of the total (thermal and suprathermal) particle pressure and total plasma beta (ratio of particle to magnetic pressure) over radial distances from 5 to 16 Saturn radii (RS = 60,258 km) is presented. The average azimuthal current density Jϕ and its separate components (inertial, pressure gradient, and anisotropy) are computed as a function of radial distance and local time and presented as equatorial maps. We explore the relative contribution of different physical mechanisms that drive the ring current at Saturn. Results show that (a) the particle pressure is controlled by thermal plasma inside of 8 RS and by the hot ions beyond 12 RS, exhibiting strong local time asymmetry with higher pressures measured at the dusk and night sectors; (b) the plasma beta increases with radial distance and remains >1 beyond 8-10 RS for all local times; (c) the ring current is asymmetric in local time and forms a maximum region between 7 and 13 RS, with values up to 100-115 pA/m2; and (d) the ring current is inertial everywhere inside of 7 RS, exhibits a mixed nature between 7 and 11 RS and is pressure gradient driven beyond 11 RS, with the exception of the noon sector where the mixed nature persists. In the dawn sector, it appears strongly pressure gradient driven for a wider range of radial distance, consistent with fast return flow of hot, tenuous magnetospheric plasma following tail reconnection.

Heuristic approach to capillary pressures averaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coca, B.P.

1980-10-01

Several methods are available to average capillary pressure curves. Among these are the J-curve and regression equations of the wetting-fluid saturation in porosity and permeability (capillary pressure held constant). While the regression equation seem completely empiric, the J-curve method seems to be theoretically sound due to its expression based on a relation between the average capillary radius and the permeability-porosity ratio. An analysis is given of each of these methods.

Validation of the Andon KD-5851 upper arm blood pressure monitor, for self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Wu, Lili; Jiao, Yinghui; Wang, Chengdong; Chen, Lei; Di, Dalin; Zhang, Haiyan

2015-08-01

This study aimed to validate the Andon KD-5851 upper arm blood pressure (BP) monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. A total of 33 eligible participants were included in the study. Sequential measurements of BPs were performed using a mercury sphygmomanometer and the device, and the data analysis was carried out following precisely the ESH-IP revision 2010. The device had 82, 98, and 99 measurements within 5, 10, and 15 mmHg for systolic blood pressure and 85, 95, and 99 measurements for diastolic blood pressure, respectively. The average device-observer difference was -0.53±4.00 mmHg for systolic blood pressure and -1.15±4.06 mmHg for diastolic blood pressure. The device passed all the criteria according to the ESH-IP revision 2010. According to the validation results on the basis of the ESH-IP revision 2010, the Andon KD-5851 upper arm BP monitor can be recommended for self/home measurement in adults. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Effect of CPAP on blood pressure in patients with obstructive sleep apnea and resistant hypertension: the HIPARCO randomized clinical trial.

PubMed

Martínez-García, Miguel-Angel; Capote, Francisco; Campos-Rodríguez, Francisco; Lloberes, Patricia; Díaz de Atauri, María Josefa; Somoza, María; Masa, Juan F; González, Mónica; Sacristán, Lirios; Barbé, Ferrán; Durán-Cantolla, Joaquín; Aizpuru, Felipe; Mañas, Eva; Barreiro, Bienvenido; Mosteiro, Mar; Cebrián, Juan J; de la Peña, Mónica; García-Río, Francisco; Maimó, Andrés; Zapater, Jordi; Hernández, Concepción; Grau SanMarti, Nuria; Montserrat, Josep María

2013-12-11

More than 70% of patients with resistant hypertension have obstructive sleep apnea (OSA). However, there is little evidence about the effect of continuous positive airway pressure (CPAP) treatment on blood pressure in patients with resistant hypertension. To assess the effect of CPAP treatment on blood pressure values and nocturnal blood pressure patterns in patients with resistant hypertension and OSA. Open-label, randomized, multicenter clinical trial of parallel groups with blinded end point design conducted in 24 teaching hospitals in Spain involving 194 patients with resistant hypertension and an apnea-hypopnea index (AHI) of 15 or higher. Data were collected from June 2009 to October 2011. CPAP or no therapy while maintaining usual blood pressure control medication. The primary end point was the change in 24-hour mean blood pressure after 12 weeks. Secondary end points included changes in other blood pressure values and changes in nocturnal blood pressure patterns. Both intention-to-treat (ITT) and per-protocol analyses were performed. A total of 194 patients were randomly assigned to receive CPAP (n = 98) or no CPAP (control; n = 96). The mean AHI was 40.4 (SD, 18.9) and an average of 3.8 antihypertensive drugs were taken per patient. Baseline 24-hour mean blood pressure was 103.4 mm Hg; systolic blood pressure (SBP), 144.2 mm Hg; and diastolic blood pressure (DBP), 83 mm Hg. At baseline, 25.8% of patients displayed a dipper pattern (a decrease of at least 10% in the average nighttime blood pressure compared with the average daytime blood pressure). The percentage of patients using CPAP for 4 or more hours per day was 72.4%. When the changes in blood pressure over the study period were compared between groups by ITT, the CPAP group achieved a greater decrease in 24-hour mean blood pressure (3.1 mm Hg [95% CI, 0.6 to 5.6]; P = .02) and 24-hour DBP (3.2 mm Hg [95% CI, 1.0 to 5.4]; P = .005), but not in 24-hour SBP (3.1 mm Hg [95% CI, -0.6 to 6.7]; P = .10) compared with the control group. Moreover, the percentage of patients displaying a nocturnal blood pressure dipper pattern at the 12-week follow-up was greater in the CPAP group than in the control group (35.9% vs 21.6%; adjusted odds ratio [OR], 2.4 [95% CI, 1.2 to 5.1]; P = .02). There was a significant positive correlation between hours of CPAP use and the decrease in 24-hour mean blood pressure (r = 0.29, P = .006), SBP (r = 0.25; P = .02), and DBP (r = 0.30, P = .005). Among patients with OSA and resistant hypertension, CPAP treatment for 12 weeks compared with control resulted in a decrease in 24-hour mean and diastolic blood pressure and an improvement in the nocturnal blood pressure pattern. Further research is warranted to assess longer-term health outcomes. clinicaltrials.gov Identifier: NCT00616265.

Chemistry of Earth's Putative Steam Atmosphere

NASA Astrophysics Data System (ADS)

Fegley, B.; Schaefer, L.

2007-12-01

The concept of a steam atmosphere generated by impact devolatilization of planetesimals accreted during Earth's formation is over 20 years old (Matsui and Abe, 1986; Lange and Ahrens, 1982). Surprisingly, with the possible exception of a few qualitative remarks, no one has critically assessed this scenario. We use thermochemical equilibrium and, where relevant, thermochemical kinetic calculations to model the chemistry of the "steam" atmosphere produced by impact volatilization of different types of accreting material. We present results for our nominal conditions (1500 K, total P = 100 bar). We also studied the effects of variable temperature and total pressure. The composition of the accreting material is modeled using average compositions of the Orgueil CI chondrite, the Murchison CM2 chondrite, the Allende CV3 chondrite, average ordinary (H, L, LL) chondrites, and average enstatite (EH, EL) chondrites. The major gases released from CI and CM chondritic material are H2O, CO2, H2, H2S, CO, CH4, and SO2 in decreasing order of abundance. About 10% of the atmosphere is CO2. The major gases released from CV chondritic material are CO2, H2O, CO, H2, and SO2 in decreasing order of abundance. About 20% of the total atmosphere is steam. The major gases released from average ordinary chondritic material are H2, CO, H2O, CO2, CH4, H2S, and N2 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with steam being about 10% of the total atmosphere. The major gases released from EH chondritic material are H2, CO, H2O, CO2, N2, and CH4 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with about 10% of the total atmosphere as steam. This work was supported by the NASA Astrobiology and Origins Programs.

Calm water resistance prediction of a bulk carrier using Reynolds averaged Navier-Stokes based solver

NASA Astrophysics Data System (ADS)

Rahaman, Md. Mashiur; Islam, Hafizul; Islam, Md. Tariqul; Khondoker, Md. Reaz Hasan

2017-12-01

Maneuverability and resistance prediction with suitable accuracy is essential for optimum ship design and propulsion power prediction. This paper aims at providing some of the maneuverability characteristics of a Japanese bulk carrier model, JBC in calm water using a computational fluid dynamics solver named SHIP Motion and OpenFOAM. The solvers are based on the Reynolds average Navier-Stokes method (RaNS) and solves structured grid using the Finite Volume Method (FVM). This paper comprises the numerical results of calm water test for the JBC model with available experimental results. The calm water test results include the total drag co-efficient, average sinkage, and trim data. Visualization data for pressure distribution on the hull surface and free water surface have also been included. The paper concludes that the presented solvers predict the resistance and maneuverability characteristics of the bulk carrier with reasonable accuracy utilizing minimum computational resources.

Wafer-level hermetic vacuum packaging by bonding with a copper-tin thin film sealing ring

NASA Astrophysics Data System (ADS)

Akashi, Teruhisa; Funabashi, Hirofumi; Takagi, Hideki; Omura, Yoshiteru; Hata, Yoshiyuki

2018-04-01

A wafer-level hermetic vacuum packaging technology intended for use with MEMS devices was developed based on a copper-tin (CuSn) thin film sealing ring. To allow hermetic packaging, the shear strength of the CuSn thin film bond was improved by optimizing the pretreatment conditions. As a result, an average shear strength of 72.3 MPa was obtained and a cavity that had been hermetically sealed using wafer-level packaging (WLP) maintained its vacuum for 1.84 years. The total pressures in the cavities and the partial pressures of residual gases were directly determined with an ultra-low outgassing residual gas analyzer (RGA) system. Hermeticity was evaluated based on helium leak rates, which were calculated from helium pressures determined with the RGA system. The resulting data showed that a vacuum cavity following 1.84 years storage had a total pressure of 83.1 Pa, contained argon as the main residual gas and exhibited a helium leak rate as low as 1.67  ×  10-17 Pa · m3 s-1, corresponding to an air leak rate of 6.19  ×  10-18 Pa · m3 s-1. The RGA data demonstrate that WLP using a CuSn thin film sealing ring permits ultra-high hermeticity in conjunction with long-term vacuum packaging that is applicable to MEMS devices.

The major influence of the atmosphere on intracranial pressure: an observational study.

PubMed

Herbowski, Leszek

2017-01-01

The impact of the atmosphere on human physiology has been studied widely within the last years. In practice, intracranial pressure is a pressure difference between intracranial compartments and the surrounding atmosphere. This means that gauge intracranial pressure uses atmospheric pressure as its zero point, and therefore, this method of pressure measurement excludes the effects of barometric pressure's fluctuation. The comparison of these two physical quantities can only take place through their absolute value relationship. The aim of this study is to investigate the direct effect of barometric pressure on the absolute intracranial pressure homeostasis. A prospective observational cross-sectional open study was conducted in Szczecin, Poland. In 28 neurosurgical patients with suspected normal-pressure hydrocephalus, intracranial intraventricular pressure was monitored in a sitting position. A total of 168 intracranial pressure and atmospheric pressure measurements were performed. Absolute atmospheric pressure was recorded directly. All values of intracranial gauge pressure were converted to absolute pressure (the sum of gauge intracranial pressure and local absolute atmospheric pressure). The average absolute mean intracranial pressure in the patients is 1006.6 hPa (95 % CI 1004.5 to 1008.8 hPa, SEM 1.1), and the mean absolute atmospheric pressure is 1007.9 hPa (95 % CI 1006.3 to 1009.6 hPa, SEM 0.8). The observed association between atmospheric and intracranial pressure is strongly significant (Spearman correlation r = 0.87, p < 0.05) and all the measurements are perfectly reliable (Bland-Altman coefficient is 4.8 %). It appears from this study that changes in absolute intracranial pressure are related to seasonal variation. Absolute intracranial pressure is shown to be impacted positively by atmospheric pressure.

The major influence of the atmosphere on intracranial pressure: an observational study

NASA Astrophysics Data System (ADS)

Herbowski, Leszek

2017-01-01

The impact of the atmosphere on human physiology has been studied widely within the last years. In practice, intracranial pressure is a pressure difference between intracranial compartments and the surrounding atmosphere. This means that gauge intracranial pressure uses atmospheric pressure as its zero point, and therefore, this method of pressure measurement excludes the effects of barometric pressure's fluctuation. The comparison of these two physical quantities can only take place through their absolute value relationship. The aim of this study is to investigate the direct effect of barometric pressure on the absolute intracranial pressure homeostasis. A prospective observational cross-sectional open study was conducted in Szczecin, Poland. In 28 neurosurgical patients with suspected normal-pressure hydrocephalus, intracranial intraventricular pressure was monitored in a sitting position. A total of 168 intracranial pressure and atmospheric pressure measurements were performed. Absolute atmospheric pressure was recorded directly. All values of intracranial gauge pressure were converted to absolute pressure (the sum of gauge intracranial pressure and local absolute atmospheric pressure). The average absolute mean intracranial pressure in the patients is 1006.6 hPa (95 % CI 1004.5 to 1008.8 hPa, SEM 1.1), and the mean absolute atmospheric pressure is 1007.9 hPa (95 % CI 1006.3 to 1009.6 hPa, SEM 0.8). The observed association between atmospheric and intracranial pressure is strongly significant (Spearman correlation r = 0.87, p < 0.05) and all the measurements are perfectly reliable (Bland-Altman coefficient is 4.8 %). It appears from this study that changes in absolute intracranial pressure are related to seasonal variation. Absolute intracranial pressure is shown to be impacted positively by atmospheric pressure.

Average Skin-Friction Drag Coefficients from Tank Tests of a Parabolic Body of Revolution (NACA RM-10)

NASA Technical Reports Server (NTRS)

Mottard, Elmo J; Loposer, J Dan

1954-01-01

Average skin-friction drag coefficients were obtained from boundary-layer total-pressure measurements on a parabolic body of revolution (NACA rm-10, basic fineness ratio 15) in water at Reynolds numbers from 4.4 x 10(6) to 70 x 10(6). The tests were made in the Langley tank no. 1 with the body sting-mounted at a depth of two maximum body diameters. The arithmetic mean of three drag measurements taken around the body was in good agreement with flat-plate results, but, apparently because of the slight surface wave caused by the body, the distribution of the boundary layer around the body was not uniform over part of the Reynolds number range.

Production of NO2 from Photolysis of Peroxyacetyl Nitrate

NASA Technical Reports Server (NTRS)

Mazely, Troy L.; Friedl, Randall R.; Sander, Stanley P.

1965-01-01

Peroxyacetyl nitrate (PAN) vapor was photolyzed at 248 nm, and the NO2 photoproduct was detected by laser-induced fluorescence. The quantum yield for the production of NO2 from PAN photolysis was determined by comparison to HNO3 photolysis data taken under identical experimental conditions. The average of data collected over a range of total pressures, precursor concentrations, and buffer gases was 0.83 +/- 0.09 for the NO2 quantum yield, where the statistical uncertainty is 2 standard deviations.

Experimental Study of Transition in a Compressible Free Shear Layer

DTIC Science & Technology

1982-12-01

Pressure Probe 18 5.3.4 Pitot Probe 18 5.3.5 Total Temperature Probe 19 5.3.6 Electromechanical Positioning and Actuating 19 6. Results 22 6.1...Signal-processing gear for this probe were identical to that connected to the pitot probe , and will be described below. The minimum lateral resolution of...5.3.4 Pitot Probe The pitot probe was the principal instrument for the measurement of mean (average) flow quantities. It consisted of a 0.008" (0.02

A Comparison of the Diagnostic Accuracy of Common Office Blood Pressure Monitoring Protocols.

PubMed

Kronish, I M; Edmondson, D; Shimbo, D; Shaffer, J A; Krakoff, L R; Schwartz, J E

2018-04-20

The optimal approach to measuring office blood pressure (BP) is uncertain. We aimed to compare BP measurement protocols that differed based on numbers of readings within and between visits and by assessment method. We enrolled a sample of 707 employees without known hypertension or cardiovascular disease, and obtained 6 standardized BP readings during each of 3 office visits at least 1 week apart, using mercury sphygmomanometer and BpTRU oscillometric devices (18 readings per participant) for a total of 12,645 readings. We used confirmatory factor analysis to develop a model estimating "true" office BP that could be used to compare the probability of correctly classifying participants' office BP status using differing numbers and types of office BP readings. Averaging two systolic BP readings across two visits correctly classified participants as having BP below or above the 140 mmHg threshold at least 95% of the time if the averaged reading was <134 mmHg or >149 mmHg, respectively. Our model demonstrated that more confidence was gained by increasing the number of visits with readings than by increasing the number of readings within a visit. No clinically significant confidence was gained by dropping the first reading versus averaging all readings, nor by measuring with a manual mercury device versus with an automated oscillometric device. Averaging two BP readings across two office visits appeared to best balance increased confidence in office BP status with efficiency of BP measurement, though the preferred measurement strategy may vary with the clinical context.

Foundational Performance Analyses of Pressure Gain Combustion Thermodynamic Benefits for Gas Turbines

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Kaemming, Thomas A.

2012-01-01

A methodology is described whereby the work extracted by a turbine exposed to the fundamentally nonuniform flowfield from a representative pressure gain combustor (PGC) may be assessed. The method uses an idealized constant volume cycle, often referred to as an Atkinson or Humphrey cycle, to model the PGC. Output from this model is used as input to a scalable turbine efficiency function (i.e., a map), which in turn allows for the calculation of useful work throughout the cycle. Integration over the entire cycle yields mass-averaged work extraction. The unsteady turbine work extraction is compared to steady work extraction calculations based on various averaging techniques for characterizing the combustor exit pressure and temperature. It is found that averages associated with momentum flux (as opposed to entropy or kinetic energy) provide the best match. This result suggests that momentum-based averaging is the most appropriate figure-of-merit to use as a PGC performance metric. Using the mass-averaged work extraction methodology, it is also found that the design turbine pressure ratio for maximum work extraction is significantly higher than that for a turbine fed by a constant pressure combustor with similar inlet conditions and equivalence ratio. Limited results are presented whereby the constant volume cycle is replaced by output from a detonation-based PGC simulation. The results in terms of averaging techniques and design pressure ratio are similar.

Ambulatory blood pressure monitoring-derived short-term blood pressure variability in primary hyperparathyroidism.

PubMed

Concistrè, A; Grillo, A; La Torre, G; Carretta, R; Fabris, B; Petramala, L; Marinelli, C; Rebellato, A; Fallo, F; Letizia, C

2018-04-01

Primary hyperparathyroidism is associated with a cluster of cardiovascular manifestations, including hypertension, leading to increased cardiovascular risk. The aim of our study was to investigate the ambulatory blood pressure monitoring-derived short-term blood pressure variability in patients with primary hyperparathyroidism, in comparison with patients with essential hypertension and normotensive controls. Twenty-five patients with primary hyperparathyroidism (7 normotensive,18 hypertensive) underwent ambulatory blood pressure monitoring at diagnosis, and fifteen out of them were re-evaluated after parathyroidectomy. Short-term-blood pressure variability was derived from ambulatory blood pressure monitoring and calculated as the following: 1) Standard Deviation of 24-h, day-time and night-time-BP; 2) the average of day-time and night-time-Standard Deviation, weighted for the duration of the day and night periods (24-h "weighted" Standard Deviation of BP); 3) average real variability, i.e., the average of the absolute differences between all consecutive BP measurements. Baseline data of normotensive and essential hypertension patients were matched for age, sex, BMI and 24-h ambulatory blood pressure monitoring values with normotensive and hypertensive-primary hyperparathyroidism patients, respectively. Normotensive-primary hyperparathyroidism patients showed a 24-h weighted Standard Deviation (P < 0.01) and average real variability (P < 0.05) of systolic blood pressure higher than that of 12 normotensive controls. 24-h average real variability of systolic BP, as well as serum calcium and parathyroid hormone levels, were reduced in operated patients (P < 0.001). A positive correlation of serum calcium and parathyroid hormone with 24-h-average real variability of systolic BP was observed in the entire primary hyperparathyroidism patients group (P = 0.04, P  = 0.02; respectively). Systolic blood pressure variability is increased in normotensive patients with primary hyperparathyroidism and is reduced by parathyroidectomy, and may potentially represent an additional cardiovascular risk factor in this disease.

Increased nocturnal blood pressure in enuretic children with polyuria.

PubMed

Kruse, Anne; Mahler, Birgitte; Rittig, Soren; Djurhuus, Jens Christian

2009-10-01

We investigated the association between nocturnal blood pressure and urine production in children with enuresis. A total of 39 consecutive children with a mean age of 9.8 years (range 6.2 to 14.9) with monosymptomatic nocturnal enuresis completed a bladder diary, including 2 weeks of basic documentation and 2 with desmopressin titration from 120 to 240 microg sublingually. Arterial blood pressure was measured every 30 minutes during 24 hours and during 4 additional nights using an ambulatory blood pressure monitor. Furthermore, 10 healthy children were recruited into the study who completed a bladder diary for 5 days while measuring arterial blood pressures with documentation of all intake and voided volumes. Patients with nocturnal polyuria had significantly higher nocturnal mean arterial pressure than patients without polyuria and controls (p <0.05). Furthermore, a positive correlation was seen between nocturnal urine output and nocturnal mean arterial pressure (r = 0.32, p <0.001). Nocturnal urine output was significantly higher during wet nights than dry nights (p <0.001). However, no significant difference was found in mean arterial pressure between wet and dry nights. Nocturnal mean arterial pressure was significantly higher in children with enuresis with polyuria than in children without polyuria. There was a significant positive correlation between average nocturnal mean arterial pressure and nocturnal urine volume in the whole study. The association between nocturnal blood pressure and urine volume, and the role of blood pressure should be investigated in a larger group of children with enuresis who have nocturnal polyuria.

Effects of blood pressure reduction in mild hypertension: a systematic review and meta-analysis.

PubMed

Sundström, Johan; Arima, Hisatomi; Jackson, Rod; Turnbull, Fiona; Rahimi, Kazem; Chalmers, John; Woodward, Mark; Neal, Bruce

2015-02-03

Effects of blood pressure reduction in persons with grade 1 hypertension are unclear. To investigate whether pharmacologic blood pressure reduction prevents cardiovascular events and deaths in persons with grade 1 hypertension. Trials included in the BPLTTC (Blood Pressure Lowering Treatment Trialists' Collaboration) and trials identified from a previous review and electronic database searches. Patients without cardiovascular disease with blood pressures in the grade 1 hypertension range (140 to 159/90 to 99 mm Hg) who were randomly assigned to an active (antihypertensive drug or more intensive regimen) or control (placebo or less intensive regimen) blood pressure-lowering regimen. Individual-patient data from BPLTTC trials and aggregate data from other trials were extracted. Risk of bias was assessed for all trials. Individual-patient data involved 10 comparisons from trials where most patients had diabetes, and aggregate data involved 3 comparisons from trials of patients without diabetes. The average blood pressure reduction was about 3.6/2.4 mm Hg. Over 5 years, odds ratios were 0.86 (95% CI, 0.74 to 1.01) for total cardiovascular events, 0.72 (CI, 0.55 to 0.94) for strokes, 0.91 (CI, 0.74 to 1.12) for coronary events, 0.80 (CI, 0.57 to 1.12) for heart failure, 0.75 (CI, 0.57 to 0.98) for cardiovascular deaths, and 0.78 (CI, 0.67 to 0.92) for total deaths. Results were similar in secondary analyses. Withdrawal from treatment due to adverse effects was more common in the active groups. Blood pressure reductions and numbers of events were small. Blood pressure-lowering therapy is likely to prevent stroke and death in patients with uncomplicated grade 1 hypertension. Swedish Heart-Lung Foundation, Swedish Research Council, Australian Research Council, and National Health and Medical Research Council of Australia.

Correlation between quantitative traits and correlation between corresponding LOD scores: detection of pleiotropic effects.

PubMed

Ulgen, Ayse; Han, Zhihua; Li, Wentian

2003-12-31

We address the question of whether statistical correlations among quantitative traits lead to correlation of linkage results of these traits. Five measured quantitative traits (total cholesterol, fasting glucose, HDL cholesterol, blood pressure, and triglycerides), and one derived quantitative trait (total cholesterol divided by the HDL cholesterol) are used for phenotype correlation studies. Four of them are used for linkage analysis. We show that although correlation among phenotypes partially reflects the correlation among linkage analysis results, the LOD-score correlations are on average low. The most significant peaks found by using different traits do not often overlap. Studying covariances at specific locations in LOD scores may provide clues for further bivariate linkage analyses.

A Mobile Phone-Based Health Coaching Intervention for Weight Loss and Blood Pressure Reduction in a National Payer Population: A Retrospective Study

PubMed Central

Magana, Candy; Caballero Barajas, Karla

2017-01-01

Background The prevalence of obesity and associated metabolic conditions continue to be challenging and costly to address for health care systems; 71% of American adults were overweight, with 35% of men and 40% of women diagnosed with obesity in 2014. Digital health coaching is an innovative approach to decreasing the barriers of cost and accessibility of receiving health coaching for the prevention and management of chronic disease in overweight or obese individuals. Objective To evaluate the early impact of a mobile phone-based health coaching service on weight loss and blood pressure management in a commercially insured population. Methods This was a retrospective study using existing registry data from a pilot commercial collaboration between Vida Health and a large national insurance provider, which enrolled adult members who were overweight (body mass index >25 kg/m2) and able to engage in a mobile phone-based coaching intervention. Participants received 4 months of intensive health coaching via live video, phone, and text message through the Vida Health app. Participants were also provided with a wireless scale, pedometer, and blood pressure cuff. Of the 1012 enrolled, 763 (75.40%) participants had an initial weight upon enrollment and final weight between 3 and 5 months from enrollment; they served as our intervention group. There were 73 participants out of the 1012 (7.21%) who had weight data 4 months prior to and after Vida coaching, who served as the matched-pair control group. Results Participants in the intervention group lost an average of 3.23% total body weight (TBW) at 4 months of coaching and 28.6% (218/763) intervention participants achieved a clinically significant weight loss of 5% or more of TBW, with an average of 9.46% weight loss in this cohort. In the matched-pair control group, participants gained on average 1.81% TBW in 4 months without Vida coaching and lost, on average, 2.47% TBW after 4 months of Vida coaching, demonstrating a statistically significant difference of 4.28% in mean percentage weight change (P<.001). Among 151 intervention participants with blood pressure data, 112 (74.2%) had a baseline blood pressure that was above the goal (systolic blood pressure >120 mmHg); 55 out of 112 (49.1%) participants improved their blood pressure at 4 months by an entire hypertensive stage—as defined by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Conclusions Mobile phone app-based health coaching interventions can be an acceptable and effective means to promote weight loss and improve blood pressure management in overweight or obese individuals. Given the ubiquity of mobile phones, digital health coaching may be an innovative solution to decreasing barriers of access to much-needed weight management interventions for obesity. PMID:28596147

Lattuce growth and water use in closed, low pressure environment

NASA Astrophysics Data System (ADS)

Fowler, P.; Rygalov, V.; Wheeler, R.; Bucklin, R.; Schumacher, N.

Lettuce (Lactuca sativa L.) cv. Waldmann's Green plants were grown in a clear, hemispherical enclosure at a reduced atmospheric pressure to study the potential for using low pressure greenhouses on planetary missions. The atmosphere was maintained at 25 kPa total pressure, with ˜20 kPa of N_2, ˜5 kPa of O_2, and between 0.1 and 0.2 kPa of CO_2, supplied by CO_2 injection and a feed-back control system. A closed water cycle was maintained inside the low pressure greenhouse by recycling condensed humidity back to the plants, and only adding external water to offset water vapor leakage and uptake in the plant tissue. All plants were grown in a granular, arcillite medium (calcined clay chips), with nutrients supplied by adding time-release fertilizer (Osmocote 20-20-20). Plants were harvested after 45 days, averaging 237 g fresh mass, and 23.7 g dry mass. No obvious adverse effects were noted on the plants, with the exception of some minor "tip-burn" injury to some leaves. Additional studies are planned to compare growth and water flux (evapotranspiration) rates at higher pressures. Preliminary results suggest that water fluxes should be lower at the higher pressures provided equal vapor pressure deficits can be maintained. The results suggest that vegetative crops such as lettuce should grow well at reduced pressures if adequate water, nutrients, and CO_2 are provided.

Method and Apparatus for Monitoring of Daily Activity in Terms of Ground Reaction Forces

NASA Technical Reports Server (NTRS)

Whalen, Robert T. (Inventor); Breit, Gregory A. (Inventor)

2001-01-01

A device to record and analyze habitual daily activity in terms of the history of gait-related musculoskeletal loading is disclosed. The device consists of a pressure-sensing insole placed into the shoe or embedded in a shoe sole, which detects contact of the foot with the ground. The sensor is coupled to a portable battery-powered digital data logger clipped to the shoe or worn around the ankle or waist. During the course of normal daily activity, the system maintains a record of time-of-occurrence of all non-spurious foot-down and lift-off events. Off line, these data are filtered and converted to a history of foot-ground contact times, from which measures of cumulative musculoskeletal loading, average walking- and running-specific gait speed, total time spent walking and running, total number of walking steps and running steps, and total gait-related energy expenditure are estimated from empirical regressions of various gait parameters to the contact time reciprocal. Data are available as cumulative values or as daily averages by menu selection. The data provided by this device are useful for assessment of musculoskeletal and cardiovascular health and risk factors associated with habitual patterns of daily activity.

Blood pressure prevalences and levels for a multicultural population in Auckland, New Zealand: results from the Diabetes, Heart and Health Survey 2002/2003.

PubMed

Gentles, Dudley; Metcalf, Patricia; Dyall, Lorna; Scragg, Robert; Black, Peter; Schaaf, David; Sundborn, Gerhard; Jackson, Rod

2006-11-17

To estimate ethnic-specific raised blood pressure (RBP) prevalences, blood pressure levels, and associations of systolic blood pressure (SBP) in the Auckland region. A cross-sectional survey of adults aged between 35-74 years in the Auckland region. There were 1006 Maori, 996 Pacific people (mostly of Samoan, Tongan, Niuean, or Cook Islands origin), and 2021 Others (mainly Europeans). Approximately 1 in 3 Maori and Pacific people had RBP (defined arbitrarily as greater than and equal to 140/90 mmHg or on blood pressure-lowering treatment), compared to 1 in 5 Others. The prevalences of RBP (adjusted for age and gender) were: Maori 37%, Pacific people 38%, and Others 22%. Maori and Pacific people had higher average systolic and diastolic blood pressure levels than Others (adjusted for age and gender). This difference became non-significant when adjusted for body mass index (BMI). SBP was (on average) higher for: male gender, increased age, increased BMI, no tertiary education, high pulse rate, high cholesterol, high triglycerides, those on current blood pressure-lowering medication. SBP was (on average) lower for current cigarette smokers. Average blood pressure levels and the prevalences of RBP were higher in Pacific people and Maori compared to Others. BMI was identified as the major modifiable factor.

The biomechanical characteristics of wearing FitFlop™ sandals highlight significant alterations in gait pattern: a comparative study.

PubMed

James, Darren C; Farmer, Laura J; Sayers, Jason B; Cook, David P; Mileva, Katya N

2015-05-01

The net contribution of all muscles that act about a joint can be represented as an internal joint moment profile. This approach may be advantageous when studying footwear-induced perturbations during walking since the contribution of the smaller deeper muscles that cross the ankle joint cannot be evaluated with surface electromyography. Therefore, the present study aimed to advance the understanding of FitFlop™ footwear interaction by investigating lower extremity joint moment, and kinematic and centre of pressure profiles during gait. 28 healthy participants performed 5 walking trials in 3 conditions: a FitFlop™ sandal, a conventional sandal and an athletic trainer. Three-dimensional ankle joint, and sagittal plane knee and hip joint moments, as well as corresponding kinematics and centre of pressure trajectories were evaluated. FitFlop™ differed significantly to both the conventional sandal and athletic trainer in: average anterior position of centre of pressure trajectory (P<0.0001) and peak hip extensor moment (P=0.001) during early stance; average medial position of centre of pressure trajectory during late stance; peak ankle dorsiflexion and corresponding range of motion; peak plantarflexor moment and total negative work performed at the ankle (all P<0.0001). The present findings demonstrate that FitFlop™ footwear significantly alters the gait pattern of wearers. An anterior displacement of the centre of pressure trajectory during early stance is the primary response to the destabilising effect of the mid-sole technology, and this leads to reductions in sagittal plane ankle joint range of motion and corresponding kinetics. Future investigations should consider the clinical implications of these findings. Copyright © 2015 Elsevier Ltd. All rights reserved.

Validation of High Aspect Ratio Cooling in a 89 kN (20,000 lb(sub f)) Thrust Combustion Chamber

NASA Technical Reports Server (NTRS)

Wadel, Mary F.; Meyer, Michael L.

1996-01-01

In order to validate the benefits of high aspect ratio cooling channels in a large scale rocket combustion chamber, a high pressure, 89 kN (20,000 lbf) thrust, contoured combustion chamber was tested in the NASA Lewis Research Center Rocket Engine Test Facility. The combustion chamber was tested at chamber pressures from 5.5 to 11.0 MPa (800-1600 psia). The propellants were gaseous hydrogen and liquid oxygen at a nominal mixture ratio of six, and liquid hydrogen was used as the coolant. The combustion chamber was extensively instrumented with 30 backside skin thermocouples, 9 coolant channel rib thermocouples, and 10 coolant channel pressure taps. A total of 29 thermal cycles, each with one second of steady state combustion, were completed on the chamber. For 25 thermal cycles, the coolant mass flow rate was equal to the fuel mass flow rate. During the remaining four thermal cycles, the coolant mass flow rate was progressively reduced by 5, 6, 11, and 20 percent. Computer analysis agreed with coolant channel rib thermocouples within an average of 9 percent and with coolant channel pressure drops within an average of 20 percent. Hot-gas-side wall temperatures of the chamber showed up to 25 percent reduction, in the throat region, over that of a conventionally cooled combustion chamber. Reducing coolant mass flow yielded a reduction of up to 27 percent of the coolant pressure drop from that of a full flow case, while still maintaining up to a 13 percent reduction in a hot-gas-side wall temperature from that of a conventionally cooled combustion chamber.

Pneumatic bracing and total contact casting have equivocal effects on plantar pressure relief.

PubMed

Hartsell, H D; Fellner, C; Saltzman, C L

2001-06-01

The purpose was to examine and compare plantar pressures produced in healthy subjects while wearing a running shoe (RS), total contact cast (TCC) and 'customized' pneumatic pre-fabricated walking brace (PWB). A repeated measures design was used to compare the plantar pressures recorded for three footwear types (RS, TCC, PWB) in two body regions (forefoot, heel). Nine healthy subjects walked at a self-selected walking pace on a motorized treadmill while wearing the RS, TCC and PWB (ordered randomization). Following a five-minute acclimatization period on the treadmill with each footwear device, plantar pressures were recorded from 84 constant gait speed and step length steps using the Pedar system of in-shoe array of capacitive sensors embedded in an insert. Mean spatially averaged peak plantar pressures were recorded for the metatarsal heads and heel region for each footwear device worn by each subject. A two-way analysis of variance with repeated measures and post-hoc Tukey tests analysed the data with a significance level of p=.05. The main effects of footwear (p=.005) and body region (p=.000), and interaction effect (body region x footwear device) (p=.000) were significant. Unloading of the forefoot was 63.72% and 58.77% for the TCC and PWB, respectively, whereas loading under the heel was increased 37.09% and 34.11% for the same two devices, respectively. Patients who develop neuropathic plantar ulcers in the forefoot region, but not in the heel region, may benefit from a reduction in plantar pressures by using either the TCC or a 'customized' PWB. An alternative footwear device still needs to be found for those patients with heel ulceration.

Effects of living at two ambient temperatures on 24-h blood pressure and neuroendocrine function among obese and non-obese humans: a pilot study

NASA Astrophysics Data System (ADS)

Kanikowska, Dominika; Sato, Maki; Iwase, Satoshi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Sugenoya, Junichi

2013-05-01

The effects of environmental temperature on blood pressure and hormones in obese subjects in Japan were compared in two seasons: summer vs winter. Five obese (BMI, 32 ± 5 kg/m2) and five non-obese (BMI, 23 ±3 kg/m2) men participated in this experiment at latitude 35°10' N and longitude 136°57.9' E. The average environmental temperature was 29 ± 1 °C in summer and 3 ± 1 °C in winter. Blood samples were analyzed for leptin, ghrelin, catecholamines, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), total cholesterol, triglycerides, insulin and glucose. Blood pressure was measured over the course of 24 h in summer and winter. A Japanese version of the Profile of Mood States (POMS) questionnaire was also administered each season. Systolic and diastolic blood pressures in obese men were significantly higher in winter (lower environmental temperatures) than in summer (higher environmental temperatures). Noradrenaline and dopamine concentrations were also significantly higher at lower environmental temperatures in obese subjects, but ghrelin, TSH, fT3, fT4, insulin and glucose were not significantly different in summer and winter between obese and non-obese subjects. Leptin, total cholesterol and triglyceride concentrations were significantly higher in winter in obese than non-obese men. Results from the POMS questionnaire showed a significant rise in Confusion at lower environmental temperatures (winter) in obese subjects. In this pilot study, increased blood pressure may have been due to increased secretion of noradrenaline in obese men in winter, and the results suggest that blood pressure control in obese men is particularly important in winter.

[Effect of green alga Ulva lactuca polysaccharides supplementation on blood pressure and on atherogenic risk factors, in rats fed a high fat diet].

PubMed

Tair, Z I; Bensalah, F; Boukortt, F

2018-05-15

To highlight the benefits of green alga Ulva lactuca polysaccharides supplementation on blood pressure and atherogenic risk factors in rats fed a high fat diet. Wistar male rats were fed a high fat diet (30% sheep fat) for 3 months. At an average body weight (BW) of 360g, the rats (n=18) were divided into 3 groups and consumed, for 28 days, either a high fat diet (HFD) or a high fat diet enriched with 1% of whole green algae (WGA) powder or with 1% of its polysaccharides (PLS). In HFD, WGA and PLS supplementation reduced BW and food intake. WGA and PLS compared to HFD reduced systolic (PAS) (-17% and -19%) and diastolic (PAD) blood pressure (-38% and -39%), serum glucose (-37% and -30%, respectively), insulinemia (-55% and -74%, respectively), serum and hepatic total lipids, triglycerides, total cholesterol levels, as well as the total cholesterol concentration of low and very low density lipoproteins. The same, atherogenicity ratios and membrane fluidity decreased in the WGA and PLS vs HFD while lecithin: cholesterol acyltransferase (LCAT) activity increased (51 and 41% respectively). Ulva lactuca and its polysaccharides, one of the bioactive compounds of this macroalga, seem to have hypotensive, hypoglycemic, hypolipaemic and antiatherogenic properties that can correct or prevent certain cardiovascular complications linked to a high fat diet. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

In vitro method for assessing the biomechanics of the patellofemoral joint following total knee arthroplasty.

PubMed

Coles, L G; Gheduzzi, S; Miles, A W

2014-12-01

The patellofemoral joint is a common site of pain and failure following total knee arthroplasty. A contributory factor may be adverse patellofemoral biomechanics. Cadaveric investigations are commonly used to assess the biomechanics of the joint, but are associated with high inter-specimen variability and often cannot be carried out at physiological levels of loading. This study aimed to evaluate the suitability of a novel knee simulator for investigating patellofemoral joint biomechanics. This simulator specifically facilitated the extended assessment of patellofemoral joint biomechanics under physiological levels of loading. The simulator allowed the knee to move in 6 degrees of freedom under quadriceps actuation and included a simulation of the action of the hamstrings. Prostheses were implanted on synthetic bones and key soft tissues were modelled with a synthetic analogue. In order to evaluate the physiological relevance and repeatability of the simulator, measurements were made of the quadriceps force and the force, contact area and pressure within the patellofemoral joint using load cells, pressure-sensitive film, and a flexible pressure sensor. The results were in agreement with those previously reported in the literature, confirming that the simulator is able to provide a realistic physiological loading situation. Under physiological loading, average standard deviations of force and area measurements were substantially lower and comparable to those reported in previous cadaveric studies, respectively. The simulator replicates the physiological environment and has been demonstrated to allow the initial investigation of factors affecting patellofemoral biomechanics following total knee arthroplasty. © IMechE 2014.

Influence of Different Patellofemoral Design Variations Based on Genesis II Total Knee Endoprosthesis on Patellofemoral Pressure and Kinematics

PubMed Central

Lange, Barbara; Herzog, Yvonne; Schnauffer, Peter; Leichtle, Carmen I.; Wülker, Nikolaus

2017-01-01

In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt (p < 0.05 for 35°–80° flexion) and translation of the patella (p < 0.045 for 20°–65° and 75°–90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA. PMID:28255225

Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

PubMed

Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

2016-09-01

Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

Acoustic Effects in Classical Nucleation Theory

NASA Technical Reports Server (NTRS)

Baird, J. K.; Su, C.-H.

2017-01-01

The effect of sound wave oscillations on the rate of nucleation in a parent phase can be calculated by expanding the free energy of formation of a nucleus of the second phase in powers of the acoustic pressure. Since the period of sound wave oscillation is much shorter than the time scale for nucleation, the acoustic effect can be calculated as a time average of the free energy of formation of the nucleus. The leading non-zero term in the time average of the free energy is proportional to the square of the acoustic pressure. The Young-Laplace equation for the surface tension of the nucleus can be used to link the time average of the square of the pressure in the parent phase to its time average in the nucleus of the second phase. Due to the surface tension, the pressure in the nuclear phase is higher than the pressure in the parent phase. The effect is to lower the free energy of formation of the nucleus and increase the rate of nucleation.

[Features of arterial blood pressure in elderly persons of different ethnic groups in Yakutsk].

PubMed

Nikitin, Iu P; Tatarinova, O V; Neustroeva, V N; Shcherbakova, L V; Sidorov, A S

2013-01-01

The differences in arterial blood pressure in the sample of population in the age of 60 and older of different ethnic groups in Yakutsk, as well as its connection with the other cardiovascular diseases risk factors have been analyzed. It was shown that the average values of systolic and diastolic blood pressure in subsample of the Yakuts appeared to be lower than in Caucasoid gerontic persons. The average values of systolic arterial blood pressure both in the Yakuts and in the Caucasoids were detected higher than normal values in all age-dependent subgroups. The average values of diastolic blood pressure in both ethnic groups were within the limits of high normal level. From 60 to 90 years and older the decrease in systolic and diastolic arterial blood pressure was detected; it was more marked in Caucasoid gerontic persons. The average values of pulse pressure in the Yakuts and in the Caucasoids appeared to be higher than the existing standard and didn't have any differences in ethnic groups. In both ethnical subsamples, pulse pressure values increase was observed in persons of 60-89 years old and its decrease after 90. Persons with overweight, obesity, central (abdominal) obesity, dyslypoproteidemias irrespective of belonging to ethnical group were characterized as having higher levels of arterial blood pressure. Statistically significant differences in the levels of arterial blood pressure in the Yakuts and in the Caucasoids depending on hyperglycemia, smoking, the presence of burdened anamnesis, educational level, marital status was not detected.

Martian tidal pressure and wind fields obtained from the Mariner 9 infrared spectroscopy experiment

NASA Technical Reports Server (NTRS)

Pirraglia, J. A.; Conrath, B. J.

1973-01-01

Using temperature fields derived from the Mariner 9 infrared spectroscopy experiment, the Martian atmospheric tidal pressure and wind fields are calculated. Temperature as a function of local time, latitude, and atmospheric pressure level is obtained by secular and longitudinal averaging of the data. The resulting temperature field is approximated by a spherical harmonic expansion, retaining one symmetric and one asymmetric term for wavenumber zero and wavenumber one. Vertical averaging of the linearized momentum and continuity equations results in an inhomogeneous tidal equation for surface pressure fluctuations with the driving function related to the temperature field through the geopotential function and the hydrostatic equation. Solutions of the tidal equation show a diurnal fractional pressure amplitude approximately equal to one half of the vertically averaged diurnal fractional temperature amplitude.

Martian tidal pressure and wind fields obtained from the Mariner 9 infrared spectroscopy experiment

NASA Technical Reports Server (NTRS)

Pirraglia, J. A.; Conrath, B. J.

1974-01-01

Using temperature fields derived from the Mariner 9 infrared spectroscopy experiment, the Martian atmospheric tidal pressure and wind fields are calculated. Temperature as a function of local time, latitude, and atmospheric pressure level is obtained by secular and longitudinal averaging of the data. The resulting temperature field is approximated by a spherical harmonic expansion, retaining one symmetric and one asymmetric term each for wavenumber zero and wavenumber one. Vertical averaging of the linearized momentum and continuity equations results in an inhomogeneous tidal equation for surface pressure fluctuations with the driving function related to the temperature field through the geopotential function and the hydrostatic equation. Solutions of the tidal equation show a diurnal fractional pressure amplitude approximately equal to one-half the vertically averaged diurnal fractional temperature amplitude.

Models of brachial to finger pulse wave distortion and pressure decrement.

PubMed

Gizdulich, P; Prentza, A; Wesseling, K H

1997-03-01

To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by the Finapres technique in 53 adult human subjects. Mean pressure was subtracted from each pressure waveform and Fourier analysis applied to the pulsations. A distortion model was estimated for each subject and averaged over the group. The average inverse model was applied to the full finger pressure waveform. The pressure decrement was modelled by multiple regression on finger systolic and diastolic levels. Waveform distortion could be described by a general, frequency dependent model having a resonance at 7.3 Hz. The general inverse model has an anti-resonance at this frequency. It converts finger to brachial pulsations thereby reducing average waveform distortion from 9.7 (s.d. 3.2) mmHg per sample for the finger pulse to 3.7 (1.7) mmHg for the converted pulse. Systolic and diastolic level differences between finger and brachial arterial pressures changed from -4 (15) and -8 (11) to +8 (14) and +8 (12) mmHg, respectively, after inverse modelling, with pulse pressures correct on average. The pressure decrement model reduced both the mean and the standard deviation of systolic and diastolic level differences to 0 (13) and 0 (8) mmHg. Diastolic differences were thus reduced most. Brachial to finger pulse wave distortion due to wave reflection in arteries is almost identical in all subjects and can be modelled by a single resonance. The pressure decrement due to flow in arteries is greatest for high pulse pressures superimposed on low means.

Experimental Study on an Unsteady Pressure Gain Combustion Hypergolic Rocket Engine Concept

NASA Astrophysics Data System (ADS)

Kan, Brandon K.

An experimental study is conducted to investigate pulsed combustion in a lab-scale bipropellant rocket engine using hypergolic propellants. The propellant combination is high concentration hydrogen peroxide and a catalyst-laced triglyme fuel. A total of 50 short duration firings have been conducted; the vast majority in an open-chamber configuration. High amplitude pulsations were evident in nearly all cases and have been assessed with high frequency pressure measurements. Both pintle and unlike impinging quadlet injector types have been evaluated although the bulk of the testing was with the latter configuration. Several firings were conducted with a transparent chamber in an attempt to gain understanding using a high-speed camera in the visible spectrum. Peak chamber pressures in excess of 5000 psi have been recorded with surface mounted high frequency gages with pulsation frequencies exceeding 600 Hz. A characterization of time-averaged performance is made for the unsteady system, where time-resolved thrust and pressure measurements were attempted. While prior literature describes this system as a pulse detonation rocket engine, the combustion appears to be more "constant volume" in nature.

4D pressure MRI: validation through in-vitro experiments and simulations

NASA Astrophysics Data System (ADS)

Schiavazzi, Daniele; Amili, Omid; Coletti, Filippo

2017-11-01

Advances in MRI scan technology and recently developed acquisition sequences have led to the development of 4D flow MRI, a protocol capable of characterizing in-vivo hemodynamics in patients. Thus, the availability of phase-averaged time-resolved three-dimensional blood velocities has opened new opportunities for computing a wide spectrum of totally non-invasive hemodynamic indicators. In this regard, relative pressures play a particularly important role, as they are routinely employed in the clinic to detect cardiovascular abnormalities (e.g., in peripheral artery disease, valve stenosis, hypertension, etc.). In the first part of the talk, we discuss how the relative pressures can be robustly computed through the solution of a pressure Poisson equation and how noise in the velocities affects their estimate. Routine application of these techniques in the clinic, require however a thorough validation on multiple patients/anatomies and systematic comparisons with in-vitro and simulated representations. Thus, the second part of the talk illustrates the use of numerical simulation and in-vitro experimental protocols to validate these indicators with reference to aortic and cerebral vascular anatomies.

An experimental investigation of the internal methane pressure in hydrogen attack

NASA Technical Reports Server (NTRS)

Natan, M.; Johnson, H. H.

1983-01-01

An experimental investigation of the internal methane pressure that is the driving force for bubble growth in hydrogen attack (HA) was done on pure iron (204 ppm C) and on two low carbon steels of slightly different compositions. The methane content N (c.c gas/g. material) in attacked specimens was measured by a vacuum extraction technique. The total void volume V (c.c) was determined from density measurements before and after HA exposure. The two values, N and V, were then used in an equation of state to calculate an average methane pressure P for the attack stages beyond a density loss (d.l.) greater than 0.05 pct. It was determined that N and P depend on hydrogen exposure conditions and the presence of traces of strong carbide forming alloying elements (in steel). They are independent of specimen size and grain size over a limited range. P varies as the bubble volume increases, showing a generally decreasing trend which brings it to values lower than calculated equilibrium pressures, although well within the same order of magnitude. Possible reasons for this behavior are discussed.

The operative treatment of pressure sores in the pelvic region: A 10-year period overview

PubMed Central

Jósvay, János; Klauber, András; Both, Béla; Kelemen, Péter B.; Varga, Zsombor Z.; Pesthy, Pál Cs.

2015-01-01

Context Pelvic region pressure sores often develop following spinal cord injury. Surgery is often necessary for long standing, large-sized pressure sores not responding to conservative treatment. Authors analyze their results of a 10-year period, and identify factors contributing to the reduction of the recurrence rate. Methods A total of 119 pressure sores were operated on 98 patients in two institutions during a 10-year period (1 January 2003 to 31 December 2012). The encountered perioperative complications are summarized, and the recurrence rate is analyzed with a patient follow-up questionnaire. Results We experienced 15 perioperative complications (12.6%). All complications were fully resolved by conservative treatment. Fifty-eight returned patient replies were processed. The average follow-up time after surgery was 5.2 years. The recurrence rate was 5.47%. Conclusion The strict adherence to surgical indications, full patient compliance, specialized pre- and post-operative patient care, our routinely used preferred surgical method, all contribute to a low post-operative complication rate, long-term flap survival, and an extended recurrence free period. PMID:25299238

The operative treatment of pressure sores in the pelvic region: A 10-year period overview.

PubMed

Jósvay, János; Klauber, András; Both, Béla; Kelemen, Péter B; Varga, Zsombor Z; Pesthy, Pál Cs

2015-07-01

Pelvic region pressure sores often develop following spinal cord injury. Surgery is often necessary for long standing, large-sized pressure sores not responding to conservative treatment. Authors analyze their results of a 10-year period, and identify factors contributing to the reduction of the recurrence rate. A total of 119 pressure sores were operated on 98 patients in two institutions during a 10-year period (1 January 2003 to 31 December 2012). The encountered perioperative complications are summarized, and the recurrence rate is analyzed with a patient follow-up questionnaire. We experienced 15 perioperative complications (12.6%). All complications were fully resolved by conservative treatment. Fifty-eight returned patient replies were processed. The average follow-up time after surgery was 5.2 years. The recurrence rate was 5.47%. The strict adherence to surgical indications, full patient compliance, specialized pre- and post-operative patient care, our routinely used preferred surgical method, all contribute to a low post-operative complication rate, long-term flap survival, and an extended recurrence free period.

Experimental investigation of a Mach 6 fixed-geometry inlet featuring a swept external-internal compression flow field

NASA Technical Reports Server (NTRS)

Torrence, M. G.

1975-01-01

An investigation of a fixed-geometry, swept external-internal compression inlet was conducted at a Mach number of 6.0 and a test-section Reynolds number of 1.55 x 10 to the 7th power per meter. The test conditions was constant for all runs with stagnation pressure and temperature at 20 atmospheres and 500 K, respectively. Tests were made at angles of attack of -5 deg, 0 deg, 3 deg, and 5 deg. Measurements consisted of pitot- and static-pressure surveys in inlet throat, wall static pressures, and surface temperatures. Boundary-layer bleed was provided on the centerbody and on the cowl internal surface. The inlet performance was consistently high over the range of the angle of attack tested, with an overall average total pressure recovery of 78 percent and corresponding adiabatic kinetic-energy efficiency of 99 percent. The inlet throat flow distribution was uniform and the Mach number and pressure level were of the correct magnitude for efficient combustor design. The utilization of a swept compression field to meet the starting requirements of a fixed-geometry inlet produced neither flow instability nor a tendency to unstart.

Is atmospheric pressure change an Independent risk factor for hemoptysis?

PubMed

Araz, Omer; Ucar, Elif Yilmazel; Akgun, Metin; Aydin, Yener; Meral, Mehmet; Saglam, Leyla; Kaynar, Hasan; Gorguner, Ali Metin

2014-05-01

Hemoptysis is one of the most important and challenging symptoms in pulmonary medicine. Because of the increased number of patients with hemoptysis in certain periods of the year, we aimed to investigate whether atmospheric changes have an effect on the development of hemoptysis with or without a secondary cause. The data of patients presenting with hemoptysis between January 2006 and December 2011 were analyzed. Data on the daily atmospheric pressure (hectopascal, hPa), relative humidity (%), and temperature ((o) C) during that time were obtained. A total of 232 patients with hemoptysis, 145 male (62.5%) and 87 female (37.5%) with an average age of 48.1(±17.6), were admitted to our hospital between 2006 and 2011. The highest admission rates were in the spring season, the highest in May (n=37, 15.9%), and the lowest admission rates were in December (n=10, 4.3%). A statistically significant negative correlation was found between the number of hemoptysis cases and mean atmospheric pressure but no relative humidity or outdoor temperature. Hemoptysis is very much influenced by weather factors; in particular, low atmospheric pressures significantly affect the development of hemoptysis. Fluctuations in atmospheric pressure may also play a role in hemoptysis.

Evaluation of the accuracy of the Rotating Parallel Ray Omnidirectional Integration for instantaneous pressure reconstruction from the measured pressure gradient

NASA Astrophysics Data System (ADS)

Moreto, Jose; Liu, Xiaofeng

2017-11-01

The accuracy of the Rotating Parallel Ray omnidirectional integration for pressure reconstruction from the measured pressure gradient (Liu et al., AIAA paper 2016-1049) is evaluated against both the Circular Virtual Boundary omnidirectional integration (Liu and Katz, 2006 and 2013) and the conventional Poisson equation approach. Dirichlet condition at one boundary point and Neumann condition at all other boundary points are applied to the Poisson solver. A direct numerical simulation database of isotropic turbulence flow (JHTDB), with a homogeneously distributed random noise added to the entire field of DNS pressure gradient, is used to assess the performance of the methods. The random noise, generated by the Matlab function Rand, has a magnitude varying randomly within the range of +/-40% of the maximum DNS pressure gradient. To account for the effect of the noise distribution pattern on the reconstructed pressure accuracy, a total of 1000 different noise distributions achieved by using different random number seeds are involved in the evaluation. Final results after averaging the 1000 realizations show that the error of the reconstructed pressure normalized by the DNS pressure variation range is 0.15 +/-0.07 for the Poisson equation approach, 0.028 +/-0.003 for the Circular Virtual Boundary method and 0.027 +/-0.003 for the Rotating Parallel Ray method, indicating the robustness of the Rotating Parallel Ray method in pressure reconstruction. Sponsor: The San Diego State University UGP program.

Data Assimilation by Ensemble Kalman Filter during One-Dimensional Nonlinear Consolidation in Randomly Heterogeneous Highly Compressible Aquitards

NASA Astrophysics Data System (ADS)

Zapata Norberto, B.; Morales-Casique, E.; Herrera, G. S.

2017-12-01

Severe land subsidence due to groundwater extraction may occur in multiaquifer systems where highly compressible aquitards are present. The highly compressible nature of the aquitards leads to nonlinear consolidation where the groundwater flow parameters are stress-dependent. The case is further complicated by the heterogeneity of the hydrogeologic and geotechnical properties of the aquitards. We explore the effect of realistic vertical heterogeneity of hydrogeologic and geotechnical parameters on the consolidation of highly compressible aquitards by means of 1-D Monte Carlo numerical simulations. 2000 realizations are generated for each of the following parameters: hydraulic conductivity (K), compression index (Cc) and void ratio (e). The correlation structure, the mean and the variance for each parameter were obtained from a literature review about field studies in the lacustrine sediments of Mexico City. The results indicate that among the parameters considered, random K has the largest effect on the ensemble average behavior of the system. Random K leads to the largest variance (and therefore largest uncertainty) of total settlement, groundwater flux and time to reach steady state conditions. We further propose a data assimilation scheme by means of ensemble Kalman filter to estimate the ensemble mean distribution of K, pore-pressure and total settlement. We consider the case where pore-pressure measurements are available at given time intervals. We test our approach by generating a 1-D realization of K with exponential spatial correlation, and solving the nonlinear flow and consolidation problem. These results are taken as our "true" solution. We take pore-pressure "measurements" at different times from this "true" solution. The ensemble Kalman filter method is then employed to estimate ensemble mean distribution of K, pore-pressure and total settlement based on the sequential assimilation of these pore-pressure measurements. The ensemble-mean estimates from this procedure closely approximate those from the "true" solution. This procedure can be easily extended to other random variables such as compression index and void ratio.

Selected meteorological data for an arid site near Beatty, Nye County, Nevada, calendar year 1987

USGS Publications Warehouse

Wood, James L.; Fischer, Jeffrey M.

1992-01-01

Selected meteorological data were collected at a study site adjacent to a low-level radioactive-waste burial facility near Beatty, Nevada, for calendar year 1987. Data were collected in support of an ongoing study to estimate the potential for downward movement of radionuclides into the unsaturated sediments beneath waste-burial trenches at the facility. The data include air temperature, relative humidity, vapor pressure, incident solar radiation, windspeed, wind direction, and precipitation. The data are summarized in tables and graphs A discussion of the instrumentation used at the site is presented. Included in the discussion are the type of sensors, their reported accuracy, and mounting height of each sensor.In 1987, the average hourly air temperatures ranged from -7.6 degrees Celsius, in December, to 43.1 degrees Celsius, in July. Hourly averaged relative humidity ranged from about 12 percent to over 80 percent. Hourly vapor pressures ranged from 0.12 to 1.77 kilopascals. Daily values for maximum incident solar radiation ranged from 118 to 1,067 watts per square meter. Daily mean windspeed ranged from 1.4 to 9.4 meters per second. Monthly wind-direction patterns are shown in a series of diagrams in which wind direction is summed over 10-degree arcs from hourly averaged data. Total precipitation for 1987 was 136.4 millimeters, more than 75 percent occurring during January-April and November-December.

Border-crossing model for the diffusive coarsening of two-dimensional and quasi-two-dimensional wet foams

NASA Astrophysics Data System (ADS)

Schimming, C. D.; Durian, D. J.

2017-09-01

For dry foams, the transport of gas from small high-pressure bubbles to large low-pressure bubbles is dominated by diffusion across the thin soap films separating neighboring bubbles. For wetter foams, the film areas become smaller as the Plateau borders and vertices inflate with liquid. So-called "border-blocking" models can explain some features of wet-foam coarsening based on the presumption that the inflated borders totally block the gas flux; however, this approximation dramatically fails in the wet or unjamming limit where the bubbles become close-packed spheres and coarsening proceeds even though there are no films. Here, we account for the ever-present border-crossing flux by a new length scale defined by the average gradient of gas concentration inside the borders. We compute that it is proportional to the geometric average of film and border thicknesses, and we verify this scaling by numerical solution of the diffusion equation. We similarly consider transport across inflated vertices and surface Plateau borders in quasi-two-dimensional foams. And we show how the d A /d t =K0(n -6 ) von Neumann law is modified by the appearance of terms that depend on bubble size and shape as well as the concentration gradient length scales. Finally, we use the modified von Neumann law to compute the growth rate of the average bubble area, which is not constant.

Flight Test of a 40-Foot Nominal-Diameter Disk-Gap-Band Parachute Deployed at a Mach Number of 1.91 and a Dynamic Pressure of 11.6 Pounds per Square Foot

NASA Technical Reports Server (NTRS)

Eckstrom, Clinton V.; Preisser, John S.

1968-01-01

A 40-foot (12.2 meter) nominal-diameter disk-gap-band parachute was flight tested as part of the NASA Supersonic Planetary Entry Decelerator Program (SPED-I). The test parachute was ejected by a deployment mortar from an instrumented payload at an altitude of 140,000 feet (42.5 kilometers). The payload was at a Mach number of 1.91 and the dynamic pressure was 11.6 pounds per square foot (555 newtons per square meter) at the time the parachute deployment mortar was fired. The parachute reached suspension line stretch in 0.43 second with a resultant snatch force loading of 1990 pounds (8850 newtons). The maximum parachute opening load of 6500 pounds (28,910 newtons) came 0.61 second later at a total elapsed time from mortar firing of 1.04 seconds. The first full inflation occurred at 1.12 seconds and stable inflation was achieved at approximately 1.60 seconds. The parachute had an average axial-force coefficient of 0.53 during the deceleration period. During the steady-state descent portion of the flight test, the average effective drag coefficient was also 0.53 and pitch-yaw oscillations of the canopy averaged less than 10 degrees in the altitude region above 100,000 feet (30.5 meters).

Influence of atmospheric pressure on the incidence of spontaneous pneumothorax.

PubMed

Díaz, Raúl; Díez, Manuel Mariano; Medrano, María José; Vera, Cristina; Guillamot, Paloma; Sánchez, Ana; Ratia, Tomás; Granell, Javier

2014-01-01

This study analyses the relationship between the incidence of idiopathic spontaneous pneumothorax (ISP) and atmospheric pressure (AP). A total of 288 cases of ISP were included, 229 men and 59 women. The AP of the day of diagnosis, of the 3 prior days and the monthly average was registered. The association between the incidence of ISP and AP was analyzed by calculating standardized incidence ratio (SIR) and Poisson regression. The AP on the day of admission (mean±standard deviation) (1,017.9±7 hectopascals [hPa]) was higher than the monthly average AP (1,016.9±4.1 hPa) (P=.005). There was a monthly distribution pattern of ISP with the highest incidence in the months of January, February and September and the lowest in April. When AP was less than 1,014 hPa, there were fewer cases registered than what would statistically have been expected (58/72 cases). In contrast, when the pressure was higher than 1,019 hPa, the registered cases were more than expected (109/82 cases) (SIR=1.25; 95% CI: 1.04 to 1.51). The risk of ISP increased 1.15 times (95% CI: 1.05 to 1.25, P=.001) for each hPa of AP, regardless of sex, age and monthly average AP. A dose-response relationship was observed, with progressive increases in risk (IRR=1.06 when the AP was 1,014-1016 hPa; 1.17 hPa when the AP was 1,016-1,019 hPa and 1.69 when AP was superior to 1,019 hPa) (P for trend=.089). The AP is a risk factor for the onset of idiopathic spontaneous pneumothorax. Copyright © 2012 AEC. Published by Elsevier Espana. All rights reserved.

Numerical Modeling of Flow Control in a Boundary-Layer-Ingesting Offset Inlet Diffuser at Transonic Mach Numbers

NASA Technical Reports Server (NTRS)

Allan, Brian G.; Owens, Lewis R.

2006-01-01

This paper will investigate the validation of the NASA developed, Reynolds-averaged Navier-Stokes (RANS) flow solver, OVERFLOW, for a boundary-layer-ingesting (BLI) offset (S-shaped) inlet in transonic flow with passive and active flow control devices as well as a baseline case. Numerical simulations are compared to wind tunnel results of a BLI inlet experiment conducted at the NASA Langley 0.3-Meter Transonic Cryogenic Tunnel. Comparisons of inlet flow distortion, pressure recovery, and inlet wall pressures are performed. The numerical simulations are compared to the BLI inlet data at a free-stream Mach number of 0.85 and a Reynolds number of approximately 2 million based on the fanface diameter. The numerical simulations with and without tunnel walls are performed, quantifying tunnel wall effects on the BLI inlet flow. A comparison is made between the numerical simulations and the BLI inlet experiment for the baseline and VG vane cases at various inlet mass flow rates. A comparison is also made to a BLI inlet jet configuration for varying actuator mass flow rates at a fixed inlet mass flow rate. Overall, the numerical simulations were able to predict the baseline circumferential flow distortion, DPCP avg, very well within the designed operating range of the BLI inlet. A comparison of the average total pressure recovery showed that the simulations were able to predict the trends but had a negative 0.01 offset when compared to the experimental levels. Numerical simulations of the baseline inlet flow also showed good agreement with the experimental inlet centerline surface pressures. The vane case showed that the CFD predicted the correct trends in the circumferential distortion levels for varying inlet mass flow but had a distortion level that was nearly twice as large as the experiment. Comparison to circumferential distortion measurements for a 15 deg clocked 40 probe rake indicated that the circumferential distortion levels are very sensitive to the symmetry of the flow and that a misalignment of the vanes in the experiment could have resulted in this difference. The numerical simulations of the BLI inlet with jets showed good agreement with the circumferential inlet distortion levels for a range of jet actuator mass flow ratios at a fixed inlet mass flow rate. The CFD simulations for the jet case also predicted an average total pressure recovery offset that was 0.01 lower than the experiment as was seen in the baseline. Comparisons of the flow features for the jet cases revealed that the CFD predicted a much larger vortex at the engine fan-face when compare to the experiment.

OPERATIONAL CHARACTERISTICS OF THE ARMOUR FISSION GAS GAMMA FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terrell, C.W.; McElroy, W.N.

1958-10-31

As the reactor power level is changed frequently, the radiation levels in the gamma facility fluctuate. Data are presented to show the power dependency of the gamma dose rate and the manner of growth and decay. Additional data show the dependercy of the equilibrium gamma activity on the foel temperature and total system pressure. The final phase of the work is directed toward determining an average gamma energy by attenuation measurements with various thicknesses of several materials. The neutrou flux associated with the gas phase activity is determined by foil measurement. From the measurements of dose rate and average gammamore » energy, calculations to determine the number of curies of gas phase decay gamma activity per watt of reactor power are presented. (auth)« less

Source identification of combustion-related air pollution during an episode and afterwards in winter-time in Istanbul.

PubMed

Kuzu, S Levent

2016-10-11

Conventional air pollutants (PM 10 , CO, NO x ) gradually increased from fall to winter during 2015 in Istanbul. Several air pollution episodes were observed during this period. This study was made in order to determine polycyclic aromatic hydrocarbon (PAH) levels, identify the sources of air pollution, and make toxicity assessment based on Benzo(a)pyrene equivalent concentrations. The sampling took 14 sequential days during winter. High-pressure weather conditions prevailed at the start of the sampling. The conditions were then changed to low-pressure condition towards the end of the sampling. Strong inversion was effective on the onset of the sampling. Strong inversion was effective at the onset of the sampling. A high-volume sampler was used to collect gas and particle phase samples. Total suspended particle concentrations were between 27 and 252 μg m -3 . Sixteen PAH species were investigated. Total (gas + particle) PAH concentrations were between 76.4 and 1280.3 ng m -3 , with an average of 301.4 ng m -3 . Individual PAH concentrations were between not detected (n.d.) and 99.2 ng m -3 in the gaseous phase, and between n.d. and 11.5 ng m -3 in the particle phase. Phenanthrene had the highest share among 16 PAH compounds. Benzo(a)pyrene was not detected in 8 days. On the remaining days, its concentration ranged between 5.5 and 14.8 ng m -3 with an average of 3.7 ng m -3 . Low-molecular-weight PAHs dominated gaseous phase; inversely, high-molecular-weight PAHs dominated particle phase. Possible sources were identified by diagnostic ratios. These ratios suggested that coal combustion and diesel vehicle exhaust emissions had a substantial impact on ambient air quality. Benzo(a)pyrene equivalencies were calculated for each PAH compound in order to make toxicity assessment. Total benzo(a)pyrene equivalencies ranged between 0.4 and 30.0 ng m -3 with an average of 7.2 ng m -3 .

Validation of the Pangao PG-800B5 for clinical use and self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Chen, Wan; Zeng, Zhaolin; Li, Lizhi; Wan, Xiaofen; Wan, Yi

2014-10-01

This study aimed to validate the Pangao PG-800B5 upper arm blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010. A total of 33 participants, 16 men and 17 women, were included in the device evaluation. The protocol requirements were followed precisely. The mean age of the participants was 56.4±21.0 years (range 22-84 years). The mean systolic blood pressure was 143.6±25.5 mmHg (range 98-188 mmHg), the mean diastolic blood pressure was 85.7±17.2 mmHg (range 49-125 mmHg), and the mean arm circumference was 26.1±2.2 cm (range 23-32 cm). On average, the device overestimated the systolic blood pressure by 0.9±4.2 mmHg and diastolic blood pressure by 0.7±4.5 mmHg. The device passed all requirements, fulfilling the standards of the protocol. Therefore, the Pangao PG-800B5 upper arm blood pressure monitor can be recommended for clinical use and self-measurement in an adult population.

[The effects of a low-fat versus a low carbohydrate diet in obese adults].

PubMed

De Luis, Daniel A; Aller, Rocio; Izaola, Olatz; González Sagrado, Manuel; Conde, Rosa

2009-02-21

The aim of our study was to compare the effect of a high fat and a high protein diet vs a fat restricted diet on weight loss in obese patients. A population of 74 obesity non diabetic outpatients was analyzed in a prospective way. Patients were randomly allocated to two groups: a) diet I (low fat diet: 1500kcal/day, 52% carbohydrates, 20% proteins, 27% fats) with a distribution of fats and b) diet II (high fat and high protein diet: 1507kcal/day, 38% carbohydrates, 26% proteins, 36% fats). After three months with diet, weight, blood pressure, glucose, C reactive protein, insulin, insulin resistance, total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides were evaluated. There were randomized 35 patients (4 males and 31 females) in the group I and 39 patients (6 males and 33 females) in diet group II. In group I, systolic pressure, BMI, weight, fat free mass, fat mass total body water, intracellular body water and waist circumference decreased significantly. In group II, glucose, total cholesterol, LDL cholesterol, systolic blood, BMI, weight, fat mass, total body water and waist circumference decreased significantly. Differences among averages of parameters before treatment with both diets were not detected. No differences were detected on weight loss between a fat-restricted diet and a high fat and high protein enhanced diet.

Atmospheric pressure fluctuations in the far infrasound range and emergency transport events coded as circulatory system diseases.

PubMed

Didyk, L A; Gorgo, Yu P; Dirckx, J J J; Bogdanov, V B; Buytaert, J A N; Lysenko, V A; Didyk, N P; Vershygora, A V; Erygina, V T

2008-09-01

This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72-11.07 Pa, n = 87) compared to the low DHA (0.7-3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21-1.64, n = 229) compared to the high Rdn (1.65-7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.

Atmospheric pressure fluctuations in the far infrasound range and emergency transport events coded as circulatory system diseases

NASA Astrophysics Data System (ADS)

Didyk, L. A.; Gorgo, Yu. P.; Dirckx, J. J. J.; Bogdanov, V. B.; Buytaert, J. A. N.; Lysenko, V. A.; Didyk, N. P.; Vershygora, A. V.; Erygina, V. T.

2008-09-01

This study examines whether a relation exists between rapid atmospheric pressure fluctuations, attributed to the far infrasound frequency range (APF), and a number of emergency transport events coded as circulatory system diseases (EEC). Over an entire year, the average integral amplitudes of APF in the range of periods from 3 s to 120 s over each hour (HA) were measured. Daily dynamics of HA averaged over the year revealed a wave shape with smooth increase from night to day followed by decrease from day to night. The total daily number of EEC within the city of Kiev, Ukraine, was related to the daily mean of HA (DHA) and to the ratio of HA averaged over the day time to HA averaged over the night time (Rdn), and was checked for confounding effects of classical meteorological variables through non-parametric regression algorithms. The number of EEC were significantly higher on days with high DHA (3.72 11.07 Pa, n = 87) compared to the low DHA (0.7 3.62 Pa, n = 260, p = 0.01), as well at days with low Rdn (0.21 1.64, n = 229) compared to the high Rdn (1.65 7.2, n = 118, p = 0.03). A difference between DHA and Rdn effects on the emergency events related to different categories of circulatory diseases points to a higher sensitivity of rheumatic and cerebro-vascular diseases to DHA, and ischaemic and hypertensive diseases to Rdn. Results suggest that APF could be considered as a meteorotropic factor capable of influencing circulatory system diseases.

[Effects of a vegetarian life style on health].

PubMed

Ritter, M M; Richter, W O

1995-06-10

A vegetarian diet has a positive effect on various risk factors for coronary artery disease: these include usually lower average body weight, lower total and LDL cholesterol levels, and lower blood pressure. In conjunction with a generally more healthy way of life (more exercise, less alcohol and tobacco use), vegetarians have roughly 30% reduction in overall mortality. The prevalence of bronchial, colon and breast cancer is also lower. In particular in its strict form (total vegetarianism or veganism), a vegetarian regimen may lead to deficiency disorders, in particular vitamin B12 deficiency, which may occur especially in vegetarian children, pregnant or lactating women. Overall, however, a vegetarian regimen has a more beneficial effect on health than the usual Central European diet.

Numerical Analysis of the Trailblazer Inlet Flowfield for Hypersonic Mach Numbers

NASA Technical Reports Server (NTRS)

Steffen, C. J., Jr.; DeBonis, J. R.

1999-01-01

A study of the Trailblazer vehicle inlet was conducted using the Global Air Sampling Program (GASP) code for flight Mach numbers ranging from 4-12. Both perfect gas and finite rate chemical analysis were performed with the intention of making detailed comparisons between the two results. Inlet performance was assessed using total pressure recovery and kinetic energy efficiency. These assessments were based upon a one-dimensional stream-thrust-average of the axisymmetric flowfield. Flow visualization utilized to examine the detailed shock structures internal to this mixed-compression inlet. Kinetic energy efficiency appeared to be the least sensitive to differences between the perfect gas and finite rate chemistry results. Total pressure recovery appeared to be the most sensitive discriminator between the perfect gas and finite rate chemistry results for flight Mach numbers above Mach 6. Adiabatic wall temperature was consistently overpredicted by the perfect gas model for flight Mach numbers above Mach 4. The predicted shock structures were noticeably different for Mach numbers from 6-12. At Mach 4, the perfect gas and finite rate chemistry models collapse to the same result.

On the influence of the local maxima of total pressure on the current sheet stability to the kink-like (flapping) mode

NASA Astrophysics Data System (ADS)

Korovinskiy, D. B.; Erkaev, N. V.; Semenov, V. S.; Ivanov, I. B.; Kiehas, S. A.; Ryzhkov, I. I.

2018-02-01

The stability of the Fadeev-like current sheet with respect to transversally propagating kink-like perturbations (flapping mode) is considered in terms of two-dimensional linear magnetohydrodynamic numerical simulations. It is found that the current sheet is stable when the total pressure minimum is located in the sheet center and unstable when the maximum value is reached there. It is shown that an unstable spot of any size enforces the whole sheet to be unstable, though the increment of instability decreases with the reduction of the unstable domain. In unstable sheets, the dispersion curve of instability shows a good match with the double-gradient (DG) model prediction. Here, the typical growth rate (short-wavelength limit) is close to the DG estimate averaged over the unstable region. In stable configurations, the typical frequency matches the maximum DG estimate. The dispersion curve of oscillations demonstrates a local maximum at wavelength ˜0.7 sheet half-width, which is a new feature that is absent in simplified analytical solutions.

Simplified Physics Based Models Research Topical Report on Task #2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, Srikanta; Ganesh, Priya

We present a simplified-physics based approach, where only the most important physical processes are modeled, to develop and validate simplified predictive models of CO2 sequestration in deep saline formation. The system of interest is a single vertical well injecting supercritical CO2 into a 2-D layered reservoir-caprock system with variable layer permeabilities. We use a set of well-designed full-physics compositional simulations to understand key processes and parameters affecting pressure propagation and buoyant plume migration. Based on these simulations, we have developed correlations for dimensionless injectivity as a function of the slope of fractional-flow curve, variance of layer permeability values, and themore » nature of vertical permeability arrangement. The same variables, along with a modified gravity number, can be used to develop a correlation for the total storage efficiency within the CO2 plume footprint. Similar correlations are also developed to predict the average pressure within the injection reservoir, and the pressure buildup within the caprock.« less

Acoustical transmission-line model of the middle-ear cavities and mastoid air cells.

PubMed

Keefe, Douglas H

2015-04-01

An acoustical transmission line model of the middle-ear cavities and mastoid air cell system (MACS) was constructed for the adult human middle ear with normal function. The air-filled cavities comprised the tympanic cavity, aditus, antrum, and MACS. A binary symmetrical airway branching model of the MACS was constructed using an optimization procedure to match the average total volume and surface area of human temporal bones. The acoustical input impedance of the MACS was calculated using a recursive procedure, and used to predict the input impedance of the middle-ear cavities at the location of the tympanic membrane. The model also calculated the ratio of the acoustical pressure in the antrum to the pressure in the middle-ear cavities at the location of the tympanic membrane. The predicted responses were sensitive to the magnitude of the viscothermal losses within the MACS. These predicted input impedance and pressure ratio functions explained the presence of multiple resonances reported in published data, which were not explained by existing MACS models.

Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study.

PubMed

Franceschini, N; Fry, R C; Balakrishnan, P; Navas-Acien, A; Oliver-Williams, C; Howard, A G; Cole, S A; Haack, K; Lange, E M; Howard, B V; Best, L G; Francesconi, K A; Goessler, W; Umans, J G; Tellez-Plaza, M

2017-03-01

Cadmium (Cd) is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of Cd with hypertension has been inconsistent. We studied the association between urinary Cd concentrations, a measure of total body burden, and blood pressure in American Indians, a US population with above national average Cd burden. Urinary Cd was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking antihypertensive medications), urinary Cd ranged from 0.01 to 78.48 μg g -1 creatinine (geometric mean=0.94 μg g -1 ) and it was correlated with smoking pack-year among ever-smokers (r 2 =0.16, P<0.0001). Participants who were smokers were on average light-smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88 μg g -1 creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration (β)=1.64, P=0.002). These associations were present among light- and never-smokers (β=2.03, P=0.002, n=2627), although not significant among never-smokers (β=1.22, P=0.18, n=1260). Cd was also associated with diastolic blood pressure among light- and never-smokers (β=0.94, P=0.004). These findings suggest that there is a relationship between Cd body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk.

Cadmium body burden and increased blood pressure in middle-aged American Indians: the Strong Heart Study

PubMed Central

Franceschini, Nora; Fry, Rebecca; Balakrishnan, Poojitha; Navas-Acien, Ana; Oliver-Williams, Clare; Howard, Annie G; Cole, Shelley A; Haack, Karin; Lange, Ethan M.; Howard, Barbara V.; Best, Lyle G; Francesconi, Kevin A.; Goessler, Walter; Umans, Jason G; Tellez-Plaza, Maria

2016-01-01

Cadmium is an environmental pollutant that has been associated with cardiovascular disease in populations, but the relationship of cadmium with hypertension has been inconsistent. We studied the association between urinary cadmium concentrations, a measure of total body burden, and blood pressure in American Indians, a U.S. population with above national average cadmium burden. Urinary cadmium (Cd) was measured using inductively coupled plasma mass spectrometry, and adjusted for urinary creatinine concentration. Among 3,714 middle-aged American Indian participants of the Strong Heart Study (mean age 56 years, 41% male, 67% ever-smokers, 23% taking anti-hypertensive medications), urinary Cd ranged from 0.01 to 78.48 μg/g creatinine (geometric mean=0.94 μg/g) and it was correlated with smoking pack-year among ever-smokers (r2=0.16, P<0.0001). Participants who were smokers were on average light smokers (mean 10.8 pack-years), and urinary Cd was similarly elevated in light- and never-smokers (geometric means of 0.88 μg/g creatinine for both categories). Log-transformed urinary Cd was significantly associated with higher systolic blood pressure in models adjusted for age, sex, geographic area, body mass index, smoking (ever vs. never, and cumulative pack-years) and kidney function (mean blood pressure difference by lnCd concentration [β]=1.64, P=0.002). These associations were present among light- and never-smokers (β=2.03, P=0.002, n=2,627), although not significant among never-smokers (β=1.22, P=0.18, n=1,260). Cd was also associated with diastolic blood pressure among light- and never-smokers (β=0.94, P=0.004). These findings suggest there is a relationship between cadmium body burden and increased blood pressure in American Indians, a population with increased cardiovascular disease risk. PMID:27629244

[Experimental evaluation of the role of the coronary sinus pressure in the regulation of coronary return volume via the coronary sinus. Surgical considerations in atrio-pulmonary diversion procedures].

PubMed

Fantidis, P; Fernández Ruiz, M A; Madero Jarabo, R; Moreno Granados, F; Cordovilla Zurdo, G; Sanz Galeote, E

1990-11-01

In order to find out the validity of the vascular waterfall mechanism in coronary venous circulation, the role of coronary sinus pressure in the regulation of coronary return volume via the coronary sinus is studied in healthy animals. An experimental model of pressure regulation in the coronary sinus was prepared, and aortic pressure, EKG and the cardiac output (measured by thermodilution) were recorded. The return volume via the coronary sinus was measured at coronary sinus pressure of 10 or less, 15, 20, and 25 mmHg or more, for a total of 36 determinations. Increased coronary sinus pressure did not produce significant changes in aortic pressure, heart rate, cardiac index or coronary return volume via coronary sinus. When coronary sinus pressure was 25 mmHg or more, there was a significant decline in the average of coronary return volume via coronary sinus. Nevertheless, stepwise variant regression showed that the coronary sinus pressure per se does not condition the volume of coronary return via the coronary sinus. Our results suggest that in the healthy animals, the vascular waterfall mechanism in coronary venous circulation is not valid. Our results suggest that in the correction of congenital cardiac malformations using atriopulmonary anastomosis procedures, employing techniques that ensure coronary sinus drainage into the left atrium, in order to avoid the hemodynamic repercussions attributable to the vascular waterfall mechanism, is not justified.

An inlet analysis for the NASA hypersonic research engine aerothermodynamic integration model

NASA Technical Reports Server (NTRS)

Andrews, E. H., Jr.; Russell, J. W.; Mackley, E. A.; Simmonds, A. L.

1974-01-01

A theoretical analysis for the inlet of the NASA Hypersonic Research Engine (HRE) Aerothermodynamic Integration Model (AIM) has been undertaken by use of a method-of-characteristics computer program. The purpose of the analysis was to obtain pretest information on the full-scale HRE inlet in support of the experimental AIM program (completed May 1974). Mass-flow-ratio and additive-drag-coefficient schedules were obtained that well defined the range effected in the AIM tests. Mass-weighted average inlet total-pressure recovery, kinetic energy efficiency, and throat Mach numbers were obtained.

Determination of the Frictional Behavior at Compaction of Powder Materials Consisting of Spray-Dried Granules

NASA Astrophysics Data System (ADS)

Staf, Hjalmar; Olsson, Erik; Lindskog, Per; Larsson, Per-Lennart

2018-03-01

The frictional behavior during powder compaction and ejection is studied using an instrumented die with eight radial sensors. The average friction over the total powder pillar is used to determine a local friction coefficient at each sensor. By comparing forces at compaction with forces at ejection, it can be shown that the Coulomb's friction coefficient can be described as a function of normal pressure. Also stick phenomena has been investigated in order to assess its influence on the determination of the local friction coefficient.

Influence of Total Inertia Effects in a Thrust Curvilinear Bearing Lubricated with Newtonian Lubricants

NASA Astrophysics Data System (ADS)

Walicka, A.; Jurczak, P.

2017-12-01

In the paper, the flow of a Newtonian type of lubricant in the clearance of a curvilinear bearing is considered. It is assumed that the bearing walls are modelled as smooth and impermeable. In analytical considerations, full inertia of the longitudinal flow and partial inertia of the circumferential flow are taken into account. The equation of motion of the lubricant is solved by the modified method of averaged inertia. A thrust bearing and spherical bearing are considered, for which dimensionless pressure distributions and the bearing capacity are given.

System and method measuring fluid flow in a conduit

DOEpatents

Ortiz, Marcos German; Kidd, Terrel G.

1999-01-01

A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.

The values of intrapleural pressure before the removal of chest tube in non-complicated pulmonary lobectomies.

PubMed

Refai, Majed; Brunelli, Alessandro; Varela, Gonzalo; Novoa, Nuria; Pompili, Cecilia; Jimenez, Marcelo F; Aranda, José Luis; Sabbatini, Armando

2012-04-01

Digitalized chest drainage systems allow for quantification of air leak and measurement of intrapleural pressure. Little is known about the value of intrapleural pressure during the postoperative phase and its role in the recovering process after pulmonary resection. The objective of this investigation was to measure the values of pleural pressure immediately before the removal of chest tube after different types of pulmonary lobectomy. Prospective observational analysis on 203 consecutive patients submitted to pulmonary lobectomy during a 12-month period at two centres. Multiple measurements were recorded in the last hour before the removal of chest tube and averaged for the analysis. All patients were seated in bed in a 45° up-right position or in a chair, had a single chest tube and were not connected to suction during the evaluation period. Analysis of variance (ANOVA) was used to assess the differences in pleural pressure between different types of lobectomies. The average maximum, minimum and differential pressures were -6.1, -19.5 and 13.3 cmH(2)O, respectively. The average pressures were similar in all types of lobectomies (ANOVA, P = 0.2) and ranged from -11 to -13 cmH(2)O, with the exception of right upper bilobectomy (-20 cmH(2)O, all P-values vs. other types of lobectomies <0.05). Similar values were also recorded for maximum pressures (range -4.4 to -8.4 cmH(2)O) and minimum pressures (-31.6 cmH(2)O vs. ranged from -15.4 to -20.5 cmH(2)O, all P-values <0.01). The average pleural pressure was not associated with FEV1 (P = 0.9), DLCO (P = 0.2) or FEV1/FVC ratio (P = 0.6), when tested with linear regression. Similarly, the average pleural pressure was similar in patients with and without COPD (-12.1 vs. -13.0 cmH(2)O, P = 0.4). The ANOVA test was used to assess differences in pressures between different lobectomies. The so-called water seal status may actually correspond to intrapleural pressures ranging from -13 to -20 cmH(2)O. Modern electronic chest drainage devices allow a stable control of the intrapleural pressure. Thus, the values found in this study may be used as target pressures for different types of lobectomies, in order to favour lung recovery after surgery.

A Mobile Phone-Based Health Coaching Intervention for Weight Loss and Blood Pressure Reduction in a National Payer Population: A Retrospective Study.

PubMed

Mao, Alice Yuqing; Chen, Connie; Magana, Candy; Caballero Barajas, Karla; Olayiwola, J Nwando

2017-06-08

The prevalence of obesity and associated metabolic conditions continue to be challenging and costly to address for health care systems; 71% of American adults were overweight, with 35% of men and 40% of women diagnosed with obesity in 2014. Digital health coaching is an innovative approach to decreasing the barriers of cost and accessibility of receiving health coaching for the prevention and management of chronic disease in overweight or obese individuals. To evaluate the early impact of a mobile phone-based health coaching service on weight loss and blood pressure management in a commercially insured population. This was a retrospective study using existing registry data from a pilot commercial collaboration between Vida Health and a large national insurance provider, which enrolled adult members who were overweight (body mass index >25 kg/m2) and able to engage in a mobile phone-based coaching intervention. Participants received 4 months of intensive health coaching via live video, phone, and text message through the Vida Health app. Participants were also provided with a wireless scale, pedometer, and blood pressure cuff. Of the 1012 enrolled, 763 (75.40%) participants had an initial weight upon enrollment and final weight between 3 and 5 months from enrollment; they served as our intervention group. There were 73 participants out of the 1012 (7.21%) who had weight data 4 months prior to and after Vida coaching, who served as the matched-pair control group. Participants in the intervention group lost an average of 3.23% total body weight (TBW) at 4 months of coaching and 28.6% (218/763) intervention participants achieved a clinically significant weight loss of 5% or more of TBW, with an average of 9.46% weight loss in this cohort. In the matched-pair control group, participants gained on average 1.81% TBW in 4 months without Vida coaching and lost, on average, 2.47% TBW after 4 months of Vida coaching, demonstrating a statistically significant difference of 4.28% in mean percentage weight change (P<.001). Among 151 intervention participants with blood pressure data, 112 (74.2%) had a baseline blood pressure that was above the goal (systolic blood pressure >120 mmHg); 55 out of 112 (49.1%) participants improved their blood pressure at 4 months by an entire hypertensive stage-as defined by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Mobile phone app-based health coaching interventions can be an acceptable and effective means to promote weight loss and improve blood pressure management in overweight or obese individuals. Given the ubiquity of mobile phones, digital health coaching may be an innovative solution to decreasing barriers of access to much-needed weight management interventions for obesity. ©Alice Yuqing Mao, Connie Chen, Candy Magana, Karla Caballero Barajas, J Nwando Olayiwola. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 08.06.2017.

Beyond Bernoulli

PubMed Central

Donati, Fabrizio; Myerson, Saul; Bissell, Malenka M.; Smith, Nicolas P.; Neubauer, Stefan; Monaghan, Mark J.; Nordsletten, David A.

2017-01-01

Background— Transvalvular peak pressure drops are routinely assessed noninvasively by echocardiography using the Bernoulli principle. However, the Bernoulli principle relies on several approximations that may not be appropriate, including that the majority of the pressure drop is because of the spatial acceleration of the blood flow, and the ejection jet is a single streamline (single peak velocity value). Methods and Results— We assessed the accuracy of the Bernoulli principle to estimate the peak pressure drop at the aortic valve using 3-dimensional cardiovascular magnetic resonance flow data in 32 subjects. Reference pressure drops were computed from the flow field, accounting for the principles of physics (ie, the Navier–Stokes equations). Analysis of the pressure components confirmed that the spatial acceleration of the blood jet through the valve is most significant (accounting for 99% of the total drop in stenotic subjects). However, the Bernoulli formulation demonstrated a consistent overestimation of the transvalvular pressure (average of 54%, range 5%–136%) resulting from the use of a single peak velocity value, which neglects the velocity distribution across the aortic valve plane. This assumption was a source of uncontrolled variability. Conclusions— The application of the Bernoulli formulation results in a clinically significant overestimation of peak pressure drops because of approximation of blood flow as a single streamline. A corrected formulation that accounts for the cross-sectional profile of the blood flow is proposed and adapted to both cardiovascular magnetic resonance and echocardiographic data. PMID:28093412

Development of a high resolution plantar pressure monitoring pad based on fiber Bragg grating (FBG) sensors.

PubMed

Suresh, R; Bhalla, S; Hao, J; Singh, C

2015-01-01

High importance is given to plantar pressure monitoring in the field of biomedical engineering for the diagnosis of posture related ailments associated with diseases such as diabetes and gonarthrosis. This paper presents the proof-of-concept development of a new high resolution plantar pressure monitoring pad based on fiber Bragg grating (FBG) sensors. In the proposed configuration, the FBG sensors are embedded within layers of carbon composite material (CCM) in turn conforming to an arc shape. A total of four such arc shaped sensors are instrumented in the pad at the locations of the forefoot and the hind foot. As a test of the pad, static plantar pressure is monitored on normal subjects under various posture conditions. The pad is evaluated both as a standalone platform as well as a pad inserted inside a standard shoe. An average pressure sensitivity of 1.2 pm/kPa and a resolution of approximately 0.8 kPa is obtained in this special configuration. The pad is found to be suitable in both configurations- stand-alone pad as well as an insert inside a standard shoe. The proposed set up offers a cost-effective high resolution and accurate plantar pressure measurement system suitable for clinical deployment. The novelty of the developed pressure pad lies in its ability to be used both as platform type as well as inserted in-sole type sensor system.

Computations of unsteady multistage compressor flows in a workstation environment

NASA Technical Reports Server (NTRS)

Gundy-Burlet, Karen L.

1992-01-01

High-end graphics workstations are becoming a necessary tool in the computational fluid dynamics environment. In addition to their graphic capabilities, workstations of the latest generation have powerful floating-point-operation capabilities. As workstations become common, they could provide valuable computing time for such applications as turbomachinery flow calculations. This report discusses the issues involved in implementing an unsteady, viscous multistage-turbomachinery code (STAGE-2) on workstations. It then describes work in which the workstation version of STAGE-2 was used to study the effects of axial-gap spacing on the time-averaged and unsteady flow within a 2 1/2-stage compressor. The results included time-averaged surface pressures, time-averaged pressure contours, standard deviation of pressure contours, pressure amplitudes, and force polar plots.

Evaluating the Impact of a Patient-centered Remote Monitoring Program on Adherence to Negative Pressure Wound Therapy.

PubMed

Griffin, Leah; Casillas, Laura Leyva

2018-03-01

A remote therapy monitoring (RTM) system has been developed for use with a negative pressure wound therapy (NPWT) unit for patients in the home care setting. In conjunction with RTM, a network of trained professionals call patients when their NPWT usage is low and provide education to assist with therapy adherence. The objective of this evaluation is to examine the relationship between the RTM system and patient adherence. One hundred ninety-eight home care patients receiving NPWT with RTM between December 2016 and April 2017 were included. A total of 979 calls were made, with an average of 4.9 calls per patient. Among 198 patients, 195 received a welcome call, 157 received a call due to low adherence, and 35 had an escalation call made to their treating nurse. Of the 157 patients who required at least 1 call due to low adherence, 153 were successfully contacted at least once. The day following the patient call, adherence increased 73% of the time by an average of 8.5 hours. This evaluation suggests there is an ability to influence patient adherence through active engagement, potentially improving outcomes and reducing wound costs.

A comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharge in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Guangsheng; Tan, Zhenyu, E-mail: tzy@sdu.edu.cn; Pan, Jie

In this work, a comparative study on the frequency effects of the electrical characteristics of the pulsed dielectric barrier discharges in He/O{sub 2} and in Ar/O{sub 2} at atmospheric pressure has been performed by means of the numerical simulation based on a 1-D fluid model at frequencies below 100 kHz. The frequency dependences of the characteristic quantities of the discharges in the two gases have been systematically calculated and analyzed under the oxygen concentrations below 2%. The characteristic quantities include the discharge current density, the averaged electron density, the electric field, and the averaged electron temperature. Especially, the frequency effects onmore » the averaged particle densities of the reactive species have also been calculated. This work gives the following significant results. For the two gases, there are two bipolar discharges in one period of applied voltage pulse under the considered frequency range and oxygen concentrations, as occurred in the pure noble gases. The frequency affects the two discharges in He/O{sub 2}, but in Ar/O{sub 2}, it induces a strong effect only on the first discharge. For the first discharge in each gas, there is a characteristic frequency at which the characteristic quantities reach their respective minimum, and this frequency appears earlier for Ar/O{sub 2}. For the second discharge in Ar/O{sub 2}, the averaged electron density presents a slight variation with the frequency. In addition, the discharge in Ar/O{sub 2} is strong and the averaged electron temperature is low, compared to those in He/O{sub 2.} The total averaged particle density of the reactive species in Ar/O{sub 2} is larger than those in He/O{sub 2} by about one order of magnitude.« less

Computational fluid dynamics study of the variable-pitch split-blade fan concept

NASA Technical Reports Server (NTRS)

Kepler, C. E.; Elmquist, A. R.; Davis, R. L.

1992-01-01

A computational fluid dynamics study was conducted to evaluate the feasibility of the variable-pitch split-blade supersonic fan concept. This fan configuration was conceived as a means to enable a supersonic fan to switch from the supersonic through-flow type of operation at high speeds to a conventional fan with subsonic inflow and outflow at low speeds. During this off-design, low-speed mode of operation, the fan would operate with a substantial static pressure rise across the blade row like a conventional transonic fan; the front (variable-pitch) blade would be aligned with the incoming flow, and the aft blade would remain fixed in the position set by the supersonic design conditions. Because of these geometrical features, this low speed configuration would inherently have a large amount of turning and, thereby, would have the potential for a large total pressure increase in a single stage. Such a high-turning blade configuration is prone to flow separation; it was hoped that the channeling of the flow between the blades would act like a slotted wing and help alleviate this problem. A total of 20 blade configurations representing various supersonic and transonic configurations were evaluated using a Navier Stokes CFD program called ADAPTNS because of its adaptive grid features. The flow fields generated by this computational procedure were processed by another data reduction program which calculated average flow properties and simulated fan performance. These results were employed to make quantitative comparisons and evaluations of blade performance. The supersonic split-blade configurations generated performance comparable to a single-blade supersonic, through-flow fan configuration. Simulated rotor total pressure ratios of the order of 2.5 or better were achieved for Mach 2.0 inflow conditions. The corresponding fan efficiencies were approximately 75 percent or better. The transonic split-blade configurations having large amounts of turning were able to generate large amounts of total turning and achieve simulated total pressure ratios of 3.0 or better with subsonic inflow conditions. These configurations had large losses and low fan efficiencies in the 70's percent. They had large separated regions and low velocity wakes. Additional turning and diffusion of this flow in a subsequent stator row would probably be very inefficient. The high total pressure ratios indicated by the rotor performance would be substantially reduced by the stators, and the stage efficiency would be substantially lower. Such performance leaves this dual-mode fan concept less attractive than originally postulated.

Fan Noise Source Diagnostic Test: Vane Unsteady Pressure Results

NASA Technical Reports Server (NTRS)

Envia, Edmane

2002-01-01

To investigate the nature of fan outlet guide vane pressure fluctuations and their link to rotor-stator interaction noise, time histories of vane fluctuating pressures were digitally acquired as part of the Fan Noise Source Diagnostic Test. Vane unsteady pressures were measured at seven fan tip speeds for both a radial and a swept vane configuration. Using time-domain averaging and spectral analysis, the blade passing frequency (BPF) harmonic and broadband contents of the vane pressures were individually analyzed. Significant Sound Pressure Level (SPL) reductions were observed for the swept vane relative to the radial vane for the BPF harmonics of vane pressure, but vane broadband reductions due to sweep turned out to be much smaller especially on an average basis. Cross-correlation analysis was used to establish the level of spatial coherence of broadband pressures between different locations on the vane and integral length scales of pressure fluctuations were estimated from these correlations. Two main results of this work are: (1) the average broadband level on the vane (in dB) increases linearly with the fan tip speed for both the radial and swept vanes, and (2) the broadband pressure distribution on the vane is nearly homogeneous and its integral length scale is a monotonically decreasing function of fan tip speed.

Experimental study of iron-chloride complexing in hydrothermal fluids

USGS Publications Warehouse

Fein, J.B.; Hemley, J.J.; d'Angelo, W. M.; Komninou, A.; Sverjensky, D.A.

1992-01-01

Mineral assemblage solubilities were measured in cold-seal pressure vessels as a function of pressure, temperature, and potassium chloride concentration in order to determine the nature and thermodynamic properties of iron-chloride complexes under hydrothermal conditions. The assemblage pyritepyrrhotite-magnetite was used to buffer f{hook}S2 and f{hook}O2, and K+ H+ ratios were buffered at reasonable geologic values using the assemblage potassium feldspar-muscovite (or andalusite)-quartz. The pressure-temperature ranges were 0.5-2.0 kbar and 300-600??C, and initial fluid compositions ranged from 0.01-2.0 molal KCl. With all other factors constant, the concentration of iron in solution increases with increasing temperature, with decreasing pressure, and with increasing total potassium chloride concentration. Changes in iron concentrations as a function of KCl concentration, in conjunction with charge balance, mass action, and mass balance constraints on the system, place constraints on the stoichiometry of the important iron-chloride complexes under each of the experimental conditions. Using least-squared linear regression fits to determine these slopes, the calculations yield values for the average ligand numbers that are in the range 1.2-1.9, with uncertainties ranging from ??0.1-0.6 at the several PT conditions considered. The slopes of the regressed fits to the data suggest that both FeCl+ and FeCl20 are important in the experimental fluids, with FeCl20 becoming dominant at the higher temperatures. Theoretical calculations, however, indicate that FeCl+ does not contribute significantly to the solubility. Because of the large uncertainties associated with some of the calculated average ligand numbers, we base our data analysis on the theoretical calculations. A statistical analysis is applied to the solubility data in order to determine the values and uncertainties of the dissociation constant for FeCl20 that best fit the data at each of the experimental pressures and temperatures. The calculated stability of FeCl20 increases with increasing temperature and total chloride concentration, and with decreasing pressure. The values of the dissociation constant of FeCl20that are calculated in this study are in moderately good agreement with FeCl20dissociation constants from other studies of iron-chloride complexing in supercritical fluids. Differences are likely due to different assumptions made concerning activity coefficients of aqueous species. Log kd values for full dissociation of FeCl20 at 0.5 kbar-300??C-and at 1 kbar-400, 500, and 600??C, respectively-are -3.75 ?? 0.40, -6.25 ?? 0.10, -9.19 ?? 0.44, and -13.29 ?? 0.09. ?? 1992.

Poynting vector, energy densities, and pressure of collective transverse electromagnetic fluctuations in unmagnetized plasmas

NASA Astrophysics Data System (ADS)

Schlickeiser, R.

2012-01-01

A systematic calculation of the electromagnetic properties (Poynting vector, electromagnetic energy, and pressure) of the collective transverse fluctuations in unmagnetized plasmas with velocity-anisotropic plasma particle distributions functions is presented. Time-averaged electromagnetic properties for monochromatic weakly damped wave-like fluctuations and space-averaged electromagnetic properties for monochromatic weakly propagating and aperiodic fluctuations are calculated. For aperiodic fluctuations, the Poynting vector as well as the sum of the space-averaged electric and magnetic field energy densities vanish. However, aperiodic fluctuations possess a positive pressure given by its magnetic energy density. This finite pressure density pa of aperiodic fluctuations has important consequences for the dynamics of cosmic unmagnetized plasmas such as the intergalactic medium after reionization. Adopting the standard cosmological evolution model, we show that this additional pressure changes the expansion law of the universe leading to further deceleration. Negative vacuum pressure counterbalances this deceleration to an accelerating universe provided that the negative vacuum pressure is greater than 1.5pa, which we estimate to be of the order 2.1 . 10-16 dyn cm-2.

The effect of deep-tissue massage therapy on blood pressure and heart rate.

PubMed

Kaye, Alan David; Kaye, Aaron J; Swinford, Jan; Baluch, Amir; Bawcom, Brad A; Lambert, Thomas J; Hoover, Jason M

2008-03-01

In the present study, we describe the effects of deep tissue massage on systolic, diastolic, and mean arterial blood pressure. The study involved 263 volunteers (12% males and 88% females), with an average age of 48.5. Overall muscle spasm/muscle strain was described as either moderate or severe for each patient. Baseline blood pressure and heart rate were measured via an automatic blood pressure cuff. Twenty-one (21) different soothing CDs played in the background as the deep tissue massage was performed over the course of the study. The massages were between 45 and 60 minutes in duration. The data were analyzed using analysis of variance with post-hoc Scheffe's F-test. Results of the present study demonstrated an average systolic pressure reduction of 10.4 mm Hg (p<0.06), a diastolic pressure reduction of 5.3 mm Hg (p<0.04), a mean arterial pressure reduction of 7.0 mm Hg (p<0.47), and an average heart rate reduction of 10.8 beats per minute (p<0.0003), respectively. Additional scientific research in this area is warranted.

Influence of mental stress on the plasma homocysteine level and blood pressure change in young men.

PubMed

Sawai, Asuka; Ohshige, Kenji; Kura, Naoki; Tochikubo, Osamu

2008-04-01

Objective. This study aimed to determine whether mental stress influences the plasma total homocysteine level or blood pressure in young men. Method. Twenty-seven male university students were assigned to a normal blood pressure group (24-h systolic blood pressure <125 mmHg and diastolic blood pressure <75 mmHg; 13 subjects) or a high blood pressure group (24-h systolic blood pressure > or =125 mmHg, or 24-h diastolic blood pressure > or =75 mmHg; 14 subjects). Wearing an ambulatory blood pressure monitoring device, subjects rested for 30 minutes, underwent an arithmetic test for 15 minutes, and rested again for 15 minutes. Blood samples were taken before and after the test. Plasma total homocysteine levels were measured. Heart rate, blood pressure, and sympathovagal balance were determined during the test. Results. The mean total homocysteine level at rest in the high blood pressure group was slightly, but not significantly, higher than that in the normal blood pressure group. The resting total homocysteine level was significantly higher in subjects with parental history of hypertension than in those without (p < 0.01). Blood pressure, heart rate, and the plasma total homocysteine level were increased significantly by mental stress (p < 0.05). The change in total homocysteine correlated significantly with the changes in systolic blood pressure and sympathovagal balance (p < 0.05). Conclusion. Resting total homocysteine level was significantly higher in male students with a parental history of hypertension than in those without. It was shown that mental stress elevates heart rate, blood pressure, sympathovagal activity, and the plasma total homocysteine level in young men.

Gas buildup in Lake Nyos, Cameroon: The recharge process and its consequences

USGS Publications Warehouse

Evans, William C.; Kling, G.W.; Tuttle, M.L.; Tanyileke, G.; White, L.D.

1993-01-01

The gases dissolved in Lake Nyos, Cameroon, were quantified recently (December 1989 and September 1990) by two independent techniques: in-situ measurements using a newly designed probe and laboratory analyses of samples collected in pre-evacuated stainless steel cylinders. The highest concentrations of CO2 and CH4 were 0.30 mol/kg and 1.7 mmol/kg, respectively, measured in cylinders collected 1 m above lake bottom. Probe measurements of in-situ gas pressure at three different stations showed that horizontal variations in total dissolved gas were negligible. Total dissolved-gas pressure near the lake bottom is 1.06 MPa (10.5 atm), 50% as high as the hydrostatic pressure of 2.1 MPa (21 atm). Comparing the CO2 profile constructed from the 1990 data to one obtained in May 1987 shows that CO2 concentrations have increased at depths to below 150 m. Based on these profiles, the average rate of CO2 input to bottom waters was 2.6 ?? 108 mol/a. Increased deep-water temperatures require an average heat flow of 0.32 MW into the hypolimnion over the same time period. The transport rates of CO2, heat, and major ions into the hypolimnion suggest that a low-temperature reservoir of free CO2 exists a short distance below lake bottom and that convective cycling of lake water through the sediments is involved in transporting the CO2 into the lake from the underlying diatreme. Increased CH4 concentrations at all depths below the oxycline and a high 14C content (41% modern) in the CH4 4 m above lake bottom show that much of the CH4 is biologically produced within the lake. The CH4 production rate may vary with time, but if the CO2 recharge rate remains constant, CO2 saturation of the entire hypolimnion below 50 m depth would require ???140 a, given present-day concentrations. ?? 1993.

Towards the Irving-Kirkwood limit of the mechanical stress tensor

NASA Astrophysics Data System (ADS)

Smith, E. R.; Heyes, D. M.; Dini, D.

2017-06-01

The probability density functions (PDFs) of the local measure of pressure as a function of the sampling volume are computed for a model Lennard-Jones (LJ) fluid using the Method of Planes (MOP) and Volume Averaging (VA) techniques. This builds on the study of Heyes, Dini, and Smith [J. Chem. Phys. 145, 104504 (2016)] which only considered the VA method for larger subvolumes. The focus here is typically on much smaller subvolumes than considered previously, which tend to the Irving-Kirkwood limit where the pressure tensor is defined at a point. The PDFs from the MOP and VA routes are compared for cubic subvolumes, V =ℓ3. Using very high grid-resolution and box-counting analysis, we also show that any measurement of pressure in a molecular system will fail to exactly capture the molecular configuration. This suggests that it is impossible to obtain the pressure in the Irving-Kirkwood limit using the commonly employed grid based averaging techniques. More importantly, below ℓ ≈3 in LJ reduced units, the PDFs depart from Gaussian statistics, and for ℓ =1.0 , a double peaked PDF is observed in the MOP but not VA pressure distributions. This departure from a Gaussian shape means that the average pressure is not the most representative or common value to arise. In addition to contributing to our understanding of local pressure formulas, this work shows a clear lower limit on the validity of simply taking the average value when coarse graining pressure from molecular (and colloidal) systems.

Towards the Irving-Kirkwood limit of the mechanical stress tensor.

PubMed

Smith, E R; Heyes, D M; Dini, D

2017-06-14

The probability density functions (PDFs) of the local measure of pressure as a function of the sampling volume are computed for a model Lennard-Jones (LJ) fluid using the Method of Planes (MOP) and Volume Averaging (VA) techniques. This builds on the study of Heyes, Dini, and Smith [J. Chem. Phys. 145, 104504 (2016)] which only considered the VA method for larger subvolumes. The focus here is typically on much smaller subvolumes than considered previously, which tend to the Irving-Kirkwood limit where the pressure tensor is defined at a point. The PDFs from the MOP and VA routes are compared for cubic subvolumes, V=ℓ 3 . Using very high grid-resolution and box-counting analysis, we also show that any measurement of pressure in a molecular system will fail to exactly capture the molecular configuration. This suggests that it is impossible to obtain the pressure in the Irving-Kirkwood limit using the commonly employed grid based averaging techniques. More importantly, below ℓ≈3 in LJ reduced units, the PDFs depart from Gaussian statistics, and for ℓ=1.0, a double peaked PDF is observed in the MOP but not VA pressure distributions. This departure from a Gaussian shape means that the average pressure is not the most representative or common value to arise. In addition to contributing to our understanding of local pressure formulas, this work shows a clear lower limit on the validity of simply taking the average value when coarse graining pressure from molecular (and colloidal) systems.

Towards the Irving-Kirkwood limit of the mechanical stress tensor

PubMed Central

Heyes, D. M.; Dini, D.

2017-01-01

The probability density functions (PDFs) of the local measure of pressure as a function of the sampling volume are computed for a model Lennard-Jones (LJ) fluid using the Method of Planes (MOP) and Volume Averaging (VA) techniques. This builds on the study of Heyes, Dini, and Smith [J. Chem. Phys. 145, 104504 (2016)] which only considered the VA method for larger subvolumes. The focus here is typically on much smaller subvolumes than considered previously, which tend to the Irving-Kirkwood limit where the pressure tensor is defined at a point. The PDFs from the MOP and VA routes are compared for cubic subvolumes, V=ℓ3. Using very high grid-resolution and box-counting analysis, we also show that any measurement of pressure in a molecular system will fail to exactly capture the molecular configuration. This suggests that it is impossible to obtain the pressure in the Irving-Kirkwood limit using the commonly employed grid based averaging techniques. More importantly, below ℓ≈3 in LJ reduced units, the PDFs depart from Gaussian statistics, and for ℓ=1.0, a double peaked PDF is observed in the MOP but not VA pressure distributions. This departure from a Gaussian shape means that the average pressure is not the most representative or common value to arise. In addition to contributing to our understanding of local pressure formulas, this work shows a clear lower limit on the validity of simply taking the average value when coarse graining pressure from molecular (and colloidal) systems. PMID:29166053

How strong is the impact of the Indo-ocean dipole on the surface air temperature/sea level pressure anomalies in the Mediterranean region?

NASA Astrophysics Data System (ADS)

Polonsky, Alexander B.; Basharin, Dmitry V.

2017-04-01

The aim of this paper is to study the interannual climate variability over the Mediterranean region related to the Indo-ocean dipole (IOD) using the data of re-analyses, archival data and specialized numerical experiments. It is shown that the IOD does not impact essentially the anomalies of surface air temperature (SAT) and sea level pressure (SLP) in the Mediterranean region. On average, the IOD-induced share of the SAT/SLP variance in the total variance of these fields in the Mediterranean region is smaller than 10% even in summer when it is at a maximum. However, the statistically significant IOD-induced SAT/SLP anomalies in the Mediterranean region are detectable. For definite IOD events the associated Mediterranean SAT anomalies can reach about 1 °C.

Integrally geared and integrated turbine generator energy recovery for high pressure natural gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agahi, R.R.; Ershaghi, B.; Moser, H.

1995-12-31

Recovery of pressure let-down energy dates back to the early 1980`s. Several installations have proven the feasibility and attractive pay back of using turbine generator system in lieu of throttling valves. These installations, on average, are saving up to 200,000 barrels of fuel oil per year. Since the first installation, many improvements have been implemented in turboexpander packages and the associated control systems. Based on site requirements, two alternate designs may be introduced. One is a totally encapsulated integral turboexpander generator unit. The other is an integrally geared turboexpander. Both alternatives have the flexibility necessary to cope with a widemore » range of inlet gas conditions while maintaining required outlet gas conditions. These installations are environmentally friendly (no hazardous gas leakage) and operate within an acceptable noise level.« less

System and method measuring fluid flow in a conduit

DOEpatents

Ortiz, M.G.; Kidd, T.G.

1999-05-18

A system is described for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements. 3 figs.

Extra compressibility terms for Favre-averaged two-equation models of inhomogeneous turbulent flows

NASA Technical Reports Server (NTRS)

Rubesin, Morris W.

1990-01-01

Forms of extra-compressibility terms that result from use of Favre averaging of the turbulence transport equations for kinetic energy and dissipation are derived. These forms introduce three new modeling constants, a polytropic coefficient that defines the interrelationships of the pressure, density, and enthalpy fluctuations and two constants in the dissipation equation that account for the non-zero pressure-dilitation and mean pressure gradients.

Flight Test of a 30-Foot Nominal-Diameter Disk-Gap-Band Parachute Deployed at Mach 1.56 and Dynamic Pressure of 11.4 Pounds per Square Foot

NASA Technical Reports Server (NTRS)

Eckstrom, Clinton V.; Preisser, John S.

1967-01-01

A 30-foot (9.1 meter) nominal-diameter disk-gap-band parachute (reference area 707 sq ft (65.7 m(exp 2)) was flight tested with a 200-pound (90.7 kg) instrumented payload as part of the NASA Planetary Entry Parachute Program. A deployment mortar ejected the test parachute when the payload was at a Mach number of 1.56 and a dynamic pressure of 11.4 lb/sq ft (546 newtons per m 2 ) at an altitude of 127,500 feet (38.86 km). The parachute reached suspension line stretch in 0.37 second resulting in a snatch force loading of 1270 pounds (5650 N). Canopy inflation began 0.10 second after line stretch. A delay in the opening process occurred and was apparently due to a momentary interference of the glass-fiber shroud used in packing the parachute bag in the mortar. Continuous canopy inflation began 0.73 second after initiation of deployment and 0.21 second later full inflation was attained for a total elapsed time from mortar fire of 0.94 second. The maximum opening load of 3915 pounds (17,400 newtons) occurred at the time the canopy was first fully opened. The parachute exhibited an average drag coefficient of 0.52 during the deceleration period and pitch-yaw oscillations of the canopy were less than 5 degrees. During the steady-state descent portion of the test period, the average effective drag coefficient was about 0.47 (based on vertical descent velocity and total system weight).

Design of sidewall treatment of cabin noise control of a twin engine turboprop aircraft

NASA Technical Reports Server (NTRS)

Vaicaitis, R.; Slazak, M.

1983-01-01

An analytical procedure was used to predict the noise transmission into the cabin of a twin engine general aviation aircraft. This model was then used to optimize the interior A weighted noise levels to an average value of about 85 dBA. The surface pressure noise spectral levels were selected utilizing experimental flight data and empirical predictions. The add on treatments considered in this optimization study include aluminum honeycomb panels, constrained layer damping tape, porous acoustic blankets, acoustic foams, septum barriers and limp trim panels which are isolated from the vibration of the main sidewall structure. To reduce the average noise level in the cabin from about 102 kBA (baseline) to 85 dBA (optimized), the added weight of the noise control treatment is about 2% of the total gross takeoff weight of the aircraft.

Design of sidewall treatment of cabin noise control of a twin engine turboprop aircraft

NASA Astrophysics Data System (ADS)

Vaicaitis, R.; Slazak, M.

1983-12-01

An analytical procedure was used to predict the noise transmission into the cabin of a twin engine general aviation aircraft. This model was then used to optimize the interior A weighted noise levels to an average value of about 85 dBA. The surface pressure noise spectral levels were selected utilizing experimental flight data and empirical predictions. The add on treatments considered in this optimization study include aluminum honeycomb panels, constrained layer damping tape, porous acoustic blankets, acoustic foams, septum barriers and limp trim panels which are isolated from the vibration of the main sidewall structure. To reduce the average noise level in the cabin from about 102 kBA (baseline) to 85 dBA (optimized), the added weight of the noise control treatment is about 2% of the total gross takeoff weight of the aircraft.

Towards a standard for the dynamic measurement of pressure based on laser absorption spectroscopy

PubMed Central

Douglass, K O; Olson, D A

2016-01-01

We describe an approach for creating a standard for the dynamic measurement of pressure based on the measurement of fundamental quantum properties of molecular systems. From the linewidth and intensities of ro-vibrational transitions we plan on making an accurate determination of pressure and temperature. The goal is to achieve an absolute uncertainty for time-varying pressure of 5 % with a measurement rate of 100 kHz, which will in the future serve as a method for the traceable calibration of pressure sensors used in transient processes. To illustrate this concept we have used wavelength modulation spectroscopy (WMS), due to inherent advantages over direct absorption spectroscopy, to perform rapid measurements of carbon dioxide in order to determine the pressure. The system records the full lineshape profile of a single ro-vibrational transition of CO2 at a repetition rate of 4 kHz and with a systematic measurement uncertainty of 12 % for the linewidth measurement. A series of pressures were measured at a rate of 400 Hz (10 averages) and from these measurements the linewidth was determined with a relative uncertainty of about 0.5 % on average. The pressures measured using WMS have an average difference of 0.6 % from the absolute pressure measured with a capacitance diaphragm sensor. PMID:27881884

Separation of Solid Stress From Interstitial Fluid Pressure in Pancreas Cancer Correlates With Collagen Area Fraction.

PubMed

Nieskoski, Michael D; Marra, Kayla; Gunn, Jason R; Kanick, Stephen C; Doyley, Marvin M; Hasan, Tayyaba; Pereira, Stephen P; Stuart Trembly, B; Pogue, Brian W

2017-06-01

Elevated total tissue pressure (TTP) in pancreatic adenocarcinoma is often associated with stress applied by cellular proliferation and hydrated hyaluronic acid osmotic swelling; however, the causal roles of collagen in total tissue pressure have yet to be clearly measured. This study illustrates one direct correlation between total tissue pressure and increased deposition of collagen within the tissue matrix. This observation comes from a new modification to a conventional piezoelectric pressure catheter, used to independently separate and quantify total tissue pressure, solid stress (SS), and interstitial fluid pressure (IFP) within the same tumor location, thereby clarifying the relationship between these parameters. Additionally, total tissue pressure shows a direct correlation with verteporfin uptake, demonstrating the impediment of systemically delivered molecules with increased tissue hypertension.

Phase 1, randomized, parallel-group, double-blind, placebo-controlled trial to evaluate the effects of erenumab (AMG 334) and concomitant sumatriptan on blood pressure in healthy volunteers.

PubMed

de Hoon, Jan; Van Hecken, Anne; Vandermeulen, Corinne; Herbots, Marissa; Kubo, Yumi; Lee, Ed; Eisele, Osa; Vargas, Gabriel; Gabriel, Kristin

2018-01-01

Objectives The aim of this study was to assess the effects of concomitant administration of erenumab and sumatriptan on resting blood pressure, pharmacokinetics, safety, and tolerability in healthy subjects. Methods In this phase 1, parallel-group, one-way crossover, double-blind, placebo-controlled study, healthy adult subjects were randomized (1:2) to receive either intravenous placebo and subcutaneous sumatriptan 12 mg (i.e. two 6-mg injections separated by 1 hour) or intravenous erenumab 140 mg and subcutaneous sumatriptan 12 mg. Blood pressure was measured pre-dose and at prespecified times post-dose. The primary endpoint was individual time-weighted averages of mean arterial pressure, measured from 0 hours to 2.5 hours after the first dose of sumatriptan. Pharmacokinetic parameters for sumatriptan were evaluated by calculating geometric mean ratios (erenumab and sumatriptan/placebo and sumatriptan). Adverse events and anti-erenumab antibodies were also evaluated. Results A total of 34 subjects were randomized and included in the analysis. Least squares mean (standard error) time-weighted averages of mean arterial pressure were 87.4 (1.0) mmHg for the placebo and sumatriptan group and 87.4 (1.2) mmHg for the erenumab and sumatriptan group. Mean difference in mean arterial pressure between groups was -0.04 mmHg (90% confidence interval: -2.2, 2.1). Geometric mean ratio estimates for maximum plasma concentration of sumatriptan was 0.95 (90% confidence interval: 0.82, 1.09), area under the plasma concentration-time curve (AUC) from time 0 to 6 hours was 0.98 (90% confidence interval: 0.93, 1.03), and AUC from time 0 to infinity was 1.00 (90% confidence interval: 0.96, 1.05). No clinically relevant safety findings for co-administration of sumatriptan and erenumab were identified. Conclusion Co-administration of erenumab and sumatriptan had no additional effect on resting blood pressure or on pharmacokinetics of sumatriptan. ClinicalTrials.gov, NCT02741310.

[Family physicians attitude towards quality indicator program].

PubMed

Shani, Michal; Nakar, Sasson; Azuri, Yossi

2012-10-01

Quality indicator programs for primary care are implanted throughout the world improving quality in health care. In this study, we have assessed family physicians attitudes towards the quality indicators program in Israel. Questionnaires were distributed to family physicians in various continuing educational programs. The questionnaire addressed demographics, whether the physician dealt with quality indicators, time devoted by the physician to quality indicators, pressure placed on the physician related to quality indicators, and the working environment. A total of 140 questionnaires were distributed and 91 (65%) were completed. The average physician age was 49 years (range 33-65 years]; the average working experience as a family physician was 17.8 years (range 0.5-42); 58 physicians were family medicine specialist (65.9%). Quality indicators were part of the routine work of 94% of the physicians; 72% of the physicians noted the importance of quality indicators; 84% of the physicians noted that quality indicators demand better team work; 76% of the physicians noted that quality indicators have reduced their professional independence. Pressure to deal with quality indicators was noted by 72% of the family physicians. Pressure to deal with quality indicators was related to reduced loyalty to their employer (P = 0.001), reducing their interest to practice family medicine (p < 0.001), and increasing their burnout at work (p = 0.001). It is important that policy makers find the way to leverage the advantages of quality indicator programs, without creating a heavy burden on the work of family physicians.

[PASTIS study: Evaluation of an automated office blood pressure measurement].

PubMed

Ayach, O; Sarlon Bartoli, G; Silhol, F; Demari, C; Vaïsse, B

2018-06-01

The evaluation of automated office blood pressure (AOBP) measurement compared to 24-hour ambulatory BP monitoring (ABPM), Home BP measurement and manual BP. A total of 123 hypertensive patients were included. Overall, 68 completed the 4 measurement: Manual BP in the office (Omron 705 CP 3 measurements), ABPM (Spacelab of 96 measurement/per 24hours), Home BP (18 measurement during 3 days), AOBP using the SPRINT methodology: lying patient, isolated with an automatic measurement (Dinamap) every minutes during 8minutes (average of the last 3 measurement). Twenty-two out of 123 patients (26%) did not complete the Home BP measurement. The average of AOBP measurement using SPRINT is 132±12/69±9mmHg, of ABPM 134±13/79±9, of Home BP: 135±13/70±13 and of manual BP: 138±13/72±11mmHg The Bland & Altman method highlight that the AOBP, the ABPM and home BP measurement are 3 substitutable methods. The confidence interval is smaller between the ABPM and the AOBP than with the home BP. The automated office blood pressure, as the Home BP measurement, can be considered a reliable substitute for the ABPM, when the later is not accessible, and when a repeated therapeutic evaluation is needed, or when the home BP measurement is not done. These results encourage us to use it more frequently as the Canadian Hypertension Education Program recommend it. Copyright © 2018. Published by Elsevier Masson SAS.

The effect of different classes of beta-antagonists on clinical and experimental hypertension.

PubMed

Fitzgerald, J D

1982-01-01

The reference beta adrenoceptor antagonist propranolol reduces blood pressure in about 60% of patients with essential hypertension. Pressure is reduced in the supine, and erect positions without postural hypotension as well as during exercise. The average extent of pressure reduction is approximately 26/16 mm.Hg. Though all clinically available beta antagonists reduce blood pressure, the profile may be modified by both adrenotropic and non-adrenotropic ancillary properties. Of the adrenotropic properties, potency influences dose frequency and total body burden of drug. Selective beta 1 antagonism may enhance safety without reducing efficacy in patients with obstructive airways disease. Selective beta 2 blockade does not reduce blood pressure in experimental models or normal subjects, but the response in patients is unknown. Partial agonism may reduce efficacy if the degree of stimulant activity is too great. Of the non-adrenotropic properties, membrane stabilising properties are of relevance only in so far as such agents undergo extensive biotransformation resulting in either reduced efficacy when drugs are used at fixed doses or the formation of biologically active metabolites. The additional properties of either alpha adrenergic blockade or inhibition of vascular smooth muscle tone modify both the speed of onset and the haemodynamic profile. The interaction of these ancillary pharmacological properties is evaluated in this review.

Hypertension prevalence, awareness, treatment, and control and sodium intake in Shandong Province, China: baseline results from Shandong-Ministry of Health Action on Salt Reduction and Hypertension (SMASH), 2011.

PubMed

Bi, Zhenqiang; Liang, Xiaofeng; Xu, Aiqiang; Wang, Linghong; Shi, Xiaoming; Zhao, Wenhua; Ma, Jixiang; Guo, Xiaolei; Zhang, Xiaofei; Zhang, Jiyu; Ren, Jie; Yan, Liuxia; Lu, Zilong; Wang, Huicheng; Tang, Junli; Cai, Xiaoning; Dong, Jing; Zhang, Juan; Chu, Jie; Engelgau, Michael; Yang, Quanhe; Hong, Yuling; Wang, Yu

2014-05-22

In China, population-based blood pressure levels and prevalence of hypertension are increasing. Meanwhile, sodium intake, a major risk factor for hypertension, is high. In 2011, to develop intervention priorities for a salt reduction and hypertension control project in Shandong Province (population 96 million), a cross-sectional survey was conducted to collect information on sodium intake and hypertension prevalence, awareness, treatment, and control. Complex, multistage sampling methods were used to select a provincial-representative adult sample. Blood pressure was measured and a survey conducted among all participants; condiments were weighed in the household, a 24-hour dietary recall was conducted, and urine was collected. Hypertension was determined by blood pressure measured on a single occasion and self-reported use of antihypertension medications. Overall, 23.4% (95% confidence interval [CI], 20.9%-26.0%) of adults in Shandong were estimated to have hypertension. Among those classified as having hypertension, approximately one-third (34.5%) reported having hypertension, approximately one-fourth (27.5%) reported taking medications, and one-seventh (14.9%) had their blood pressure controlled (<140/<90 mm Hg). Estimated total average daily dietary sodium intake was 5,745 mg (95% CI, 5,428 mg-6,063 mg). Most dietary sodium (80.8%) came from salt and high-salt condiments added during cooking: a sodium intake of 4,640 mg (95% CI, 4,360 mg-4,920 mg). The average daily urinary sodium excretion was 5,398 mg (95% CI, 5,112 mg-5,683 mg). Hypertension and excessive sodium intake in adults are major public health problems in Shandong Province, China.

Hypertension Prevalence, Awareness, Treatment, and Control and Sodium Intake in Shandong Province, China: Baseline Results From Shandong–Ministry of Health Action on Salt Reduction and Hypertension (SMASH), 2011

PubMed Central

Bi, Zhenqiang; Liang, Xiaofeng; Xu, Aiqiang; Wang, Linghong; Shi, Xiaoming; Zhao, Wenhua; Ma, Jixiang; Guo, Xiaolei; Zhang, Xiaofei; Zhang, Jiyu; Ren, Jie; Yan, Liuxia; Lu, Zilong; Wang, Huicheng; Tang, Junli; Cai, Xiaoning; Dong, Jing; Zhang, Juan; Chu, Jie; Engelgau, Michael; Yang, Quanhe; Hong, Yuling

2014-01-01

Introduction In China, population-based blood pressure levels and prevalence of hypertension are increasing. Meanwhile, sodium intake, a major risk factor for hypertension, is high. In 2011, to develop intervention priorities for a salt reduction and hypertension control project in Shandong Province (population 96 million), a cross-sectional survey was conducted to collect information on sodium intake and hypertension prevalence, awareness, treatment, and control. Methods Complex, multistage sampling methods were used to select a provincial-representative adult sample. Blood pressure was measured and a survey conducted among all participants; condiments were weighed in the household, a 24-hour dietary recall was conducted, and urine was collected. Hypertension was determined by blood pressure measured on a single occasion and self-reported use of antihypertension medications. Results Overall, 23.4% (95% confidence interval [CI], 20.9%–26.0%) of adults in Shandong were estimated to have hypertension. Among those classified as having hypertension, approximately one-third (34.5%) reported having hypertension, approximately one-fourth (27.5%) reported taking medications, and one-seventh (14.9%) had their blood pressure controlled (<140/<90 mm Hg). Estimated total average daily dietary sodium intake was 5,745 mg (95% CI, 5,428 mg–6,063 mg). Most dietary sodium (80.8%) came from salt and high-salt condiments added during cooking: a sodium intake of 4,640 mg (95% CI, 4,360 mg–4,920 mg). The average daily urinary sodium excretion was 5,398 mg (95% CI, 5,112 mg–5,683 mg). Conclusion Hypertension and excessive sodium intake in adults are major public health problems in Shandong Province, China. PMID:24854239

Pressure Ulcers in the United States' Inpatient Population From 2008 to 2012: Results of a Retrospective Nationwide Study.

PubMed

Bauer, Karen; Rock, Kathryn; Nazzal, Munier; Jones, Olivia; Qu, Weikai

2016-11-01

Pressure ulcers are common, increase patient morbidity and mortality, and costly for patients, their families, and the health care system. A retrospective study was conducted to evaluate the impact of pressure ulcers on short-term outcomes in United States inpatient populations and to identify patient characteristics associated with having 1 or more pressure ulcers. The US Nationwide Inpatient Sample (NIS) database was analyzed using the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9 CM) diagnosis codes as the screening tool for all inpatient pressure ulcers recorded from 2008 to 2012. Patient demographics and comorbid conditions, as identified by ICD-9 code, were extracted, along with primary outcomes of length of stay (LOS), total hospital charge (TC), inhospital mortality, and discharge disposition. Continuous variables with normal distribution were expressed in terms of mean and standard deviation. Group comparisons were performed using t-test or ANOVA test. Continuous nonnormal distributed variables such as LOS and TC were expressed in terms of median, and nonparametric tests were used to compare the differences between groups. Categorical data were presented in terms of percentages of the number of cases within each group. Chi-squared tests were used to compare categorical data in different groups. For multivariate analysis, linear regressions (for continuous variable) and logistic regression (for categorical variables) were used to analyze the possible risk factors for the investigated outcomes of LOS, TC, inhospital mortality, and patient disposition. Coefficients were calculated with multivariate regression with all included patients versus patients with pressure ulcers alone. The 5-year average number of admitted patients with at least 1 pressure ulcer was determined to be 670 767 (average overall rate: 1.8%). Statistically significant differences between patients with and without pressure ulcers were observed for median LOS (7 days [mean 11.1 ± 15] compared to 3 days [mean 4.6 ± 6.8]) and median TC ($36 500 [mean $72 000 ± $122 900] compared to $17 200 [mean $32 200 ± $57 500]). The mortality rate in patients with a pressure ulcer was significantly higher than in patients without a pressure ulcer (9.1% versus 1.8%, OR = 5.08, CI: 5.03-5.1, P <0.001). Pressure ulcers were significantly more common in patients who were older or had malnutrition. The results of this study confirm the importance of prevention initiatives to help reduce the negative impact of pressure ulcers on patient outcomes and costs of care.

Numerical simulation and experiment on effect of ultrasonic in polymer extrusion processing

NASA Astrophysics Data System (ADS)

Wan, Yue; Fu, ZhiHong; Wei, LingJiao; Zang, Gongzheng; Zhang, Lei

2018-01-01

The influence of ultrasonic wave on the flow field parameters and the precision of extruded products are studied. Firstly, the effect of vibration power on the average velocity of the outlet, the average viscosity of the die section, the average shear rate and the inlet pressure of the die section were studied by using the Polyflow software. Secondly, the effects of ultrasonic strength on the die temperature and the drop of die pressure were studied experimentally by different head temperature and different screw speed. Finally, the relationship between die pressure and extrusion flow rate under different ultrasonic power were studied through experiments.

Comparison of endotracheal tube cuff pressure values before and after training seminar.

PubMed

Özcan, Ayça Tuba Dumanlı; Döğer, Cihan; But, Abdülkadir; Kutlu, Işık; Aksoy, Şemsi Mustafa

2018-06-01

It is recommended that endotracheal cuff (ETTc) pressure be between 20 and 30 cm H 2 O. In this present study, we intend to observe average cuff pressure values in our clinic and the change in these values after the training seminar. The cuff pressure values of 200 patients intubated following general anesthesia induction in the operating theatre were measured following intubation. One hundred patients whose values were measured before the training seminar held for all physician assistants, and 100 patients whose values were measured after the training seminar were regarded as Group 1 and Group 2, respectively. Cuff pressures of both groups were recorded, and the difference between them was shown. Moreover, cuff pressure values were explored according to the working period of the physician assistants. There was no significant difference between the groups in terms of age, gender and tube diameters. Statistically significant difference was found between cuff pressure values before and after the training (p < 0.001). Average pressure measure for Group I was 54 cm H 2 O, while average pressure in Group II declined to 33 cm H 2 O. It was observed that as the working period and experience of physician assistants increased, cuff pressure values decreased, however no statistically significant different was found (p < 0.375). We believe that clinical experience does not have significant effects on cuff pressure and that training seminars held at intervals would prevent high cuff pressure values and potential complications.

SOIL GAS RADON MEASUREMENT AROUND FAULT LINES ON THE WESTERN SECTION OF THE NORTH ANATOLIAN FAULT ZONE IN TURKEY.

PubMed

Yakut, Hakan; Tabar, Emre; Yildirim, Eray; Zenginerler, Zemine; Ertugral, Filiz; Demirci, Nilufer

2017-04-15

Soil gas radon activity measurements were made around the western section of the North Anatolian Fault Zone. In the study, the variation of radon concentration at 12 different locations along the fault line was monitored by using LR-115 (solid-state nuclear track detectors) detectors for 12-monthly periods. Twelve radon stations were determined in the study region, and in each station, LR-115 films were installed in the borehole of ∼50 cm. The recorded radon concentration varies from 29 to 7059 Bqm-3 with an average value of 1930 Bqm-3. The influence of meteorological parameters such as temperature, pressure, total rainfall and humidity on soil radon concentrations in the study area was also investigated. The positive and poor correlation was observed between average value of 222Rn concentration and temperature. There is a reverse proportion between radon level with other meteorological factors (humidity, pressure and rainfall). The results show that the measured soil gas radon activity concentration shows seasonal variation in a highly permeable sandy-gravelly soil with definite seasons without obvious long transitional periods. The summer (from June 2013 to September 2013) is characterised by 1.8 times higher average soil gas radon activity concentration (median is 2.372 kBqm-3) than the winter (from December 2012 to March 2013) (median is 1.298 kBqm-3). © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Selected meteorological data for an arid site near Beatty, Nye County, Nevada, calendar year 1989

USGS Publications Warehouse

Wood, J.L.; Andraski, Brian J.

1992-01-01

Selected meteorological data were collected at a study site adjacent to a low-level radioactive-waste burial facility near Beatty, Nevada, for calendar year 1989. Data were collected in support of ongoing studies to estimate the potential for downward movement of radionuclides into the unsaturated sediments beneath waste-burial trenches at the facility. The data include air temperature, relative humidity, vapor pressure, incident solar radiation, windspeed, wind direction, and precipitation. The data are summarized in tables and graphs.Instrumentation used at the site is discussed. The discussion includes the type, reported accuracy, and mounting height of each sensor.In 1989, the hourly averaged air temperature ranged from -14.5 degrees Celsius, in February, to 46.0 degrees Celsius, in July. Hourly averaged relative humidity ranged from less than 12 percent to over 80 percent. Hourly vapor pressures ranged from 0.06 to 1.71 kilopascals. Daily maximum incident solar radiation values ranged from 149 to 1,084 watts per square meter. Daily mean windspeed ranged from less than 1 to 8.6 meters per second. Monthly wind direction patterns are shown in a series of diagrams in which wind direction is summed over 10-degree arcs from hourly averaged data. Wind direction was primarily from the northwest in fall, winter, and spring and varied from southeast, southwest, or northwest during the summer. Total precipitation for 1989 was 14.0 millimeters, with almost 90 percent occurring from January through May.

Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2012

USGS Publications Warehouse

Beebee, Robin A.; Schauer, Paul V.

2015-11-19

Vertical contraction and pressure flow occurred during 1 percent or smaller annual exceedance probability floods at five sites, including three aggradation sites. Contraction scour exceeded 5 feet at two sites, and total scour at piers (pier scour plus contraction scour) exceeded 5 feet at two sites. Debris accumulation increased calculated pier scour at six sites by an average of 1.2 feet. Total scour at abutments including contraction scour exceeded 5 feet at seven sites. Scour estimates seemed excessive at aggradation sites where upstream sediment supply controls scour and deposition processes, at cohesive soil sites where conservative assumptions were made for soil strength and flood duration, and for abutment scour at sites where failure of the embankment and attendant channel widening would reduce scour.

Transportation Fuels and the Hydrogen Economy

NASA Astrophysics Data System (ADS)

Gabbard, Alex

2004-11-01

An energy analysis of transportation fuels is performed for comparing automobiles and fuels currently in the marketplace as real world benchmarks projected as "hydrogen economy" requirements. Comparisons are made for ideal case average energy values at Standard Temperature and Pressure (STP) at 20°C, 1 atmosphere with no loses. "Real world" benchmarks currently in the marketplace illuminate the challenges to be met if an equivalent "hydrogen economy" is to become reality. The idea of a "hydrogen economy" is that, at some time in the future, world energy needs will be supplied in part or totally from hydrogen; in part as compared to the current "petroleum economy" that is the source of most of the world's transportation fuels and only a portion of total energy use, or hydrogen as the source of all energy consumption.

The behavior of a compressible turbulent boundary layer in a shock-wave-induced adverse pressure gradient. Ph.D. Thesis - Washington Univ., Seattle, Aug. 1972

NASA Technical Reports Server (NTRS)

Rose, W. C.

1973-01-01

The results of an experimental investigation of the mean- and fluctuating-flow properties of a compressible turbulent boundary layer in a shock-wave-induced adverse pressure gradient are presented. The turbulent boundary layer developed on the wall of an axially symmetric nozzle and test section whose nominal free-stream Mach number and boundary-layer thickness Reynolds number were 4 and 100,000, respectively. The adverse pressure gradient was induced by an externally generated conical shock wave. Mean and time-averaged fluctuating-flow data, including the complete experimental Reynolds stress tensor and experimental turbulent mass- and heat-transfer rates are presented for the boundary layer and external flow, upstream, within and downstream of the pressure gradient. The mean-flow data include distributions of total temperature throughout the region of interest. The turbulent mixing properties of the flow were determined experimentally with a hot-wire anemometer. The calibration of the wires and the interpretation of the data are discussed. From the results of the investigation, it is concluded that the shock-wave - boundary-layer interaction significantly alters the turbulent mixing characteristics of the boundary layer.

[Evaluation of super dwarf wheat growth and development in greenhouse "Svet" during cultivation in inhabited pressurized chamber

NASA Technical Reports Server (NTRS)

Sychev, V. N.; Levinskikh, M. A.; Podol'skii, I. G.; Ivanova, I. E.; Nefedova, E. L.; Livanskaia, O. G.; Derendiaeva, T. A.; Mikhailov, N. I.; Salisbury, F. B.; Bingham, G. E.;

Pressure-Dependent Detection of Carbon Monoxide Employing Wavelength Modulation Spectroscopy Using a Herriott-Type Cell.

PubMed

Li, Chuanliang; Wu, Yingfa; Qiu, Xuanbing; Wei, Jilin; Deng, Lunhua

2017-05-01

Wavelength modulation spectroscopy (WMS) combined with a multipass absorption cell has been used to measure a weak absorption line of carbon monoxide (CO) at 1.578 µm. A 0.95m Herriott-type cell provides an effective absorption path length of 55.1 m. The WMS signals from the first and second harmonic output of a lock-in amplifier (WMS-1 f and 2 f, respectively) agree with the Beer-Lambert law, especially at low concentrations. After boxcar averaging, the minimum detection limit achieved is 4.3 ppm for a measurement time of 0.125 s. The corresponding normalized detection limit is 84 ppm m Hz -1/2 . If the integrated time is increased to 88 s, the minimum detectable limit of CO can reach to 0.29 ppm based on an Allan variation analysis. The pressure-dependent relationship is validated after accounting for the pressure factor in data processing. Finally, a linear correlation between the WMS-2 f amplitudes and gas concentrations is obtained at concentration ratios less than 15.5%, and the accuracy is better than 92% at total pressure less than 62.7 Torr.

Valuing the benefits of improved marine environmental quality under multiple stressors.

PubMed

Tuhkanen, Heidi; Piirsalu, Evelin; Nõmmann, Tea; Karlõševa, Aljona; Nõmmann, Sulev; Czajkowski, Mikołaj; Hanley, Nick

2016-05-01

Many marine ecosystems are under increasing pressure from multiple stressors. In the Baltic Sea, these stressors include oil and chemical spills from shipping, nutrient run-off from land and the introduction of non-indigenous species. All of these pressures have been growing over recent years. Increasing pressures lead to reductions in environmental quality, which produce negative effects on human well-being. In this paper, the choice experiment method is used to estimate the benefits to people in Estonia resulting from reductions in pressure from multiple stressors in the Baltic Sea. The main results show that, firstly, respondents have a positive, statistically-significant willingness to pay to reduce each of the three stressors analysed. Secondly, the average willingness to pay for the improvement in the quality of all Estonian marine waters to achieve Good Environmental Status is around 65 euro per household per year, with a 95% confidence interval of 48-77 euro. Thirdly, the greatest share of value of this total economic benefit is derived from the willingness to pay for reductions in the risk of large scale oil and chemical spills. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of scale effect in compressive ice failure and implications for design

NASA Astrophysics Data System (ADS)

Taylor, Rocky Scott

The main focus of the study was the analysis of scale effect in local ice pressure resulting from probabilistic (spalling) fracture and the relationship between local and global loads due to the averaging of pressures across the width of a structure. A review of fundamental theory, relevant ice mechanics and a critical analysis of data and theory related to the scale dependent pressure behavior of ice were completed. To study high pressure zones (hpzs), data from small-scale indentation tests carried out at the NRC-IOT were analyzed, including small-scale ice block and ice sheet tests. Finite element analysis was used to model a sample ice block indentation event using a damaging, viscoelastic material model and element removal techniques (for spalling). Medium scale tactile sensor data from the Japan Ocean Industries Association (JOIA) program were analyzed to study details of hpz behavior. The averaging of non-simultaneous hpz loads during an ice-structure interaction was examined using local panel pressure data. Probabilistic averaging methodology for extrapolating full-scale pressures from local panel pressures was studied and an improved correlation model was formulated. Panel correlations for high speed events were observed to be lower than panel correlations for low speed events. Global pressure estimates based on probabilistic averaging were found to give substantially lower average errors in estimation of load compared with methods based on linear extrapolation (no averaging). Panel correlations were analyzed for Molikpaq and compared with JOIA results. From this analysis, it was shown that averaging does result in decreasing pressure for increasing structure width. The relationship between local pressure and ice thickness for a panel of unit width was studied in detail using full-scale data from the STRICE, Molikpaq, Cook Inlet and Japan Ocean Industries Association (JOIA) data sets. A distinct trend of decreasing pressure with increasing ice thickness was observed. The pressure-thickness behavior was found to be well modeled by the power law relationships Pavg = 0.278 h-0.408 MPa and Pstd = 0.172h-0.273 MPa for the mean and standard deviation of pressure, respectively. To study theoretical aspects of spalling fracture and the pressure-thickness scale effect, probabilistic failure models have been developed. A probabilistic model based on Weibull theory (tensile stresses only) was first developed. Estimates of failure pressure obtained with this model were orders of magnitude higher than the pressures observed from benchmark data due to the assumption of only tensile failure. A probabilistic fracture mechanics (PFM) model including both tensile and compressive (shear) cracks was developed. Criteria for unstable fracture in tensile and compressive (shear) zones were given. From these results a clear theoretical scale effect in peak (spalling) pressure was observed. This scale effect followed the relationship Pp,th = 0.15h-0.50 MPa which agreed well with the benchmark data. The PFM model was applied to study the effect of ice edge shape (taper angle) and hpz eccentricity. Results indicated that specimens with flat edges spall at lower pressures while those with more tapered edges spall less readily. The mean peak (failure) pressure was also observed to decrease with increased eccentricity. It was concluded that hpzs centered about the middle of the ice thickness are the zones most likely to create the peak pressures that are of interest in design. Promising results were obtained using the PFM model, which provides strong support for continued research in the development and application of probabilistic fracture mechanics to the study of scale effects in compressive ice failure and to guide the development of methods for the estimation of design ice pressures.

Cerebral blood flow velocity declines before arterial pressure in patients with orthostatic vasovagal presyncope

NASA Technical Reports Server (NTRS)

Dan, Dan; Hoag, Jeffrey B.; Ellenbogen, Kenneth A.; Wood, Mark A.; Eckberg, Dwain L.; Gilligan, David M.

2002-01-01

OBJECTIVES: We studied hemodynamic changes leading to orthostatic vasovagal presyncope to determine whether changes of cerebral artery blood flow velocity precede or follow reductions of arterial pressure. BACKGROUND: Some evidence suggests that disordered cerebral autoregulation contributes to the occurrence of orthostatic vasovagal syncope. We studied cerebral hemodynamics with transcranial Doppler recordings, and we closely examined the temporal sequence of changes of cerebral artery blood flow velocity and systemic arterial pressure in 15 patients who did or did not faint during passive 70 degrees head-up tilt. METHODS: We recorded photoplethysmographic arterial pressure, RR intervals (electrocardiogram) and middle cerebral artery blood flow velocities (mean, total, mean/RR interval; Gosling's pulsatility index; and cerebrovascular resistance [mean cerebral velocity/mean arterial pressure, MAP]). RESULTS: Eight men developed presyncope, and six men and one woman did not. Presyncopal patients reported light-headedness, diaphoresis, or a sensation of fatigue 155 s (range: 25 to 414 s) before any cerebral or systemic hemodynamic change. Average cerebral blood flow velocity (CBFV) changes (defined by an iterative linear regression algorithm) began 67 s (range: 9 to 198 s) before reductions of MAP. Cerebral and systemic hemodynamic measurements remained constant in nonsyncopal patients. CONCLUSIONS: Presyncopal symptoms and CBFV changes precede arterial pressure reductions in patients with orthostatic vasovagal syncope. Therefore, changes of cerebrovascular regulation may contribute to the occurrence of vasovagal reactions.

Influence of meteorological conditions on hospital admission in patients with acute coronary syndrome with and without ST-segment elevation: Results of the AIRACOS study.

PubMed

Dominguez-Rodriguez, A; Juarez-Prera, R A; Rodríguez, S; Abreu-Gonzalez, P; Avanzas, P

2016-05-01

Evaluate whether the meterological parameters affecting revenues in patients with ST-segment and non-ST-segment elevation ACS. A prospective cohort study was carried out. Coronary Care Unit of Hospital Universitario de Canarias We studies a total of 307 consecutive patients with a diagnosis of ST-segment and non-ST-segment elevation ACS. We analyze the average concentrations of particulate smaller than 10 and 2.5μm diameter, particulate black carbon, the concentrations of gaseous pollutants and meteorological parameters (wind speed, temperature, relative humidity and atmospheric pressure) that were exposed patients from one day up to 7 days prior to admission. None. Demographic, clinical, atmospheric particles, concentrations of gaseous pollutants and meterological parameters. A total of 138 (45%) patients were classified as ST-segment and 169 (55%) as non-ST-segment elevation ACS. No statistically significant differences in exposure to atmospheric particles in both groups. Regarding meteorological data, we did not find statistically significant differences, except for higher atmospheric pressure in ST-segment elevation ACS (999.6±2.6 vs. 998.8±2.5 mbar, P=.008). Multivariate analysis showed that atmospheric pressure was significant predictor of ST-segment elevation ACS presentation (OR: 1.14, 95% CI: 1.04-1.24, P=.004). In the patients who suffer ACS, the presence of higher number of atmospheric pressure during the week before the event increase the risk that the ST-segment elevation ACS. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Phasic changes in human right coronary blood flow before and after repair of aortic insufficiency.

PubMed

Folts, J D; Rowe, G G; Kahn, D R; Young, W P

1979-02-01

We have shown previously that acute aortic insufficiency in chronically instrumented dogs reverses the normally high ratio of diastolic to systolic coronary blood flow. Phasic blood flow in the dominant right coronary artery was measured directly with an electromagnetic flow meter during surgery in eight patients with severe aortic insufficiency before and after relacement of the aortic valve. Before the insufficiency was eliminated, right coronary flow average 116 +/- 37 ml./minute and the diastolic to systolic flow ratio was 0.88 +/- 17. Mean arterial blood pressure averaged 106 +/- 17 mm. Hg, heart rate 84 +/- 19 beats/minute, and mean diastolic pressure averaged 67 +/- 10 mm. Hg. After the aortic valve was replaced with an average heart rate of 90 +/- 15 and mean blood pressure of 103 +/- 13 mm. Hg, the average right coronary blood flow increased to 180 +/- 40 ml./minute with a D/S ratio of 2.18 +/- 0.8. In all cases the right coronary blood flow increased after the aortic insufficiency was eliminated surgically. Right coronary flow probably increased because of the improved diastolic perfusion pressure and the change from predominantly systolic to diastolic coronary flow.

Inter-Arm Difference in Brachial Blood Pressure in the General Population of Koreans.

PubMed

Song, Bo Mi; Kim, Hyeon Chang; Shim, Jee-Seon; Lee, Myung Ha; Choi, Dong Phil

2016-05-01

We investigated the inter-arm difference in blood pressure of the general Korean population to identify associated factors. A total of 806 participants aged 30 to 64 years without history of major cardiovascular disease were analyzed in this cross-sectional study. They participated in the Cardiovascular and Metabolic Disease Etiology Research Center cohort study that began in 2013. Brachial blood pressure was measured simultaneously for both arms using an automated oscillometric device equipped with two cuffs in seated position. After five minutes of rest, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured three times. The average of the three measurements was used for analysis. Multivariate logistic regression models were used to identify factors associated with inter-arm differences in blood pressure. The mean inter-arm difference was 3.3 mmHg for SBP and 2.0 mmHg for DBP. Large inter-arm differences (≥10 mmHg) in SBP and in DBP were found in 3.7% and 0.9% of subjects, respectively. A large inter-arm difference in SBP was associated with mean SBP (p=0.002) and C-reactive protein (p=0.014) while a large inter-arm different in DBP was only associated with body mass index (p=0.015). Sex, age, and anti-hypertensive medication use were not associated with differences in inter-arm blood pressure. Large inter-arm difference in blood pressure is only present in a small portion of healthy Korean adults. Our findings suggest that high SBP, chronic inflammation, and obesity may be associated with larger difference in inter-arm blood pressure.

Application of Pressure Sensitive Paint to Confined Flow at Mach Number 2.5

NASA Technical Reports Server (NTRS)

Lepicovsky, J.; Bencic, T. J.; Bruckner, R. J.

1998-01-01

Pressure sensitive paint (PSP) is a novel technology that is being used frequently in external aerodynamics. For internal flows in narrow channels, and applications at elevated nonuniform temperatures, however, there are still unresolved problems that complicate the procedures for calibrating PSP signals. To address some of these problems, investigations were carried out in a narrow channel with supersonic flows of Mach 2.5. The first set of tests focused on the distribution of the wall pressure in the diverging section of the test channel downstream of the nozzle throat. The second set dealt with the distribution of wall static pressure due to the shock/wall interaction caused by a 25 deg. wedge in the constant Mach number part of the test section. In addition, the total temperature of the flow was varied to assess the effects of temperature on the PSP signal. Finally, contamination of the pressure field data, caused by internal reflection of the PSP signal in a narrow channel, was demonstrated. The local wall pressures were measured with static taps, and the wall pressure distributions were acquired by using PSP. The PSP results gave excellent qualitative impressions of the pressure field investigated. However, the quantitative results, specifically the accuracy of the PSP data in narrow channels, show that improvements need to be made in the calibration procedures, particularly for heated flows. In the cases investigated, the experimental error had a standard deviation of +/- 8.0% for the unheated flow, and +/- 16.0% for the heated flow, at an average pressure of 11 kpa.

Postdialysis blood pressure rise predicts long-term outcomes in chronic hemodialysis patients: a four-year prospective observational cohort study

PubMed Central

2012-01-01

Background The blood pressure (BP) of a proportion of chronic hemodialysis (HD) patients rises after HD. We investigated the influence of postdialysis BP rise on long-term outcomes. Methods A total of 115 prevalent HD patients were enrolled. Because of the fluctuating nature of predialysis and postdialysis BP, systolic BP (SBP) and diastolic BP before and after HD were recorded from 25 consecutive HD sessions during a 2-month period. Patients were followed for 4 years or until death or withdrawal. Results Kaplan-Meier estimates revealed that patients with average postdialysis SBP rise of more than 5 mmHg were at the highest risk of both cardiovascular and all-cause mortality as compared to those with an average postdialysis SBP change between -5 to 5 mmHg and those with an average postdialysis SBP drop of more than 5 mmHg. Furthermore, multivariate Cox regression analysis indicated that both postdialysis SBP rise of more than 5 mmHg (HR, 3.925 [95% CI, 1.410-10.846], p = 0.008) and high cardiothoracic (CT) ratio of more than 50% (HR, 7.560 [95% CI, 2.048-27.912], p = 0.002) independently predicted all-cause mortality. We also found that patients with an average postdialysis SBP rise were associated with subclinical volume overload, as evidenced by the significantly higher CT ratio (p = 0.008). Conclusions A postdialysis SBP rise in HD patients independently predicted 4-year cardiovascular and all-cause mortality. Considering postdialysis SBP rise was associated with higher CT ratio, intensive evaluation of cardiac and volume status should be performed in patients with postdialysis SBP rise. PMID:22414233

Pressure mapping to assess seated pressure distributions and the potential risk for skin ulceration in a population of sledge hockey players and control subjects.

PubMed

Berthold, Justin; Dicianno, Brad E; Cooper, Rory A

2013-09-01

Ice sledge (or sled) hockey is a fast-paced sport that enables individuals with physical disabilities to play ice hockey. As the attraction to the sport continues to rise, the need for developing better equipment and installing preventative measures for injury will become increasingly important. One such injury includes skin pressure ulceration. A total of 26 subjects including active controls and those with spinal cord injury, multiple sclerosis, limb amputation and traumatic brain injury were studied using a pressure mapping device at the 2012 National Disabled Veterans Winter Sports Clinic to determine the risk for skin pressure ulceration and the impact of cushioning and knee angle positioning on seated pressure distributions. Sledge hockey athletes may be at increased risk for skin pressure ulceration based on seated pressure distribution data. This experiment failed to demonstrate a benefit for specialty cushioning in either group. Interestingly, knee angle positioning, particularly, knee extension significantly lowered the average seated pressures. When considering the risk for skin pressure ulceration, knee angle positioning is of particular clinical importance. More research is warranted, specifically targeting novel cushion and sledge designs and larger groups of individuals with sensory loss and severe spinal deformities. Implications for Rehabilitation Ice sledge (or sled) hockey is a fast-paced and growing adaptive sport played at the Paralympic level. Rehabilitation professionals should consider the potential for skin ulceration in this population of athletes. The effects of cushioning used in the sledge design warrants further investigation. Knee angle positioning; particularly, knee extension significantly lowers seated pressures and may reduce the potential for skin ulceration.

Simulation of Surface Pressure Induced by Vortex/Body Interaction

NASA Astrophysics Data System (ADS)

He, M.; Islam, M.; Veitch, B.; Bose, N.; Colbourne, M. B.; Liu, P.

When a strong vortical wake impacts a structure, the pressure on the impacted surface sees large variations in its amplitude. This pressure fluctuation is one of the main sources causing severe structural vibration and hydrodynamic noise. Economical and effective prediction methods of the fluctuating pressure are required by engineers in many fields. This paper presents a wake impingement model (WIM) that has been incorporated into a panel method code, Propella, and its applications in simulations of a podded propeller wake impacting on a strut. Simulated strut surface pressure distributions and variations are compared with experimental data in terms of time-averaged components and phase-averaged components. The pressure comparisons show that the calculated results are in a good agreement with experimental data.

Model to Design Drip Hose Lateral Line

NASA Astrophysics Data System (ADS)

Ludwig, Rafael; Cury Saad, João Carlos

2014-05-01

Introduction The design criterion for non-pressure compensating drip hose is normally to have 10% of flow variation (Δq) in the lateral line, corresponding to 20% of head pressure variation (ΔH). Longer lateral lines in drip irrigation systems using conventional drippers provide cost reduction, but it is necessary to obtain to the uniformity of irrigation [1]. The use of Δq higher levels can provide longer lateral lines. [4] proposes the use of a 30% Δq and he found that this value resulted in distribution uniformity over 80%. [1] considered it is possible to extend the lateral line length using two emitters spacing in different section. He assumed that the spacing changing point would be at 40% of the total length, because this is approximately the location of the average flow according with [2]. [3] found that, for practical purposes, the average pressure is located at 40% of the length of the lateral line and that until this point it has already consumed 75% of total pressure head loss (hf ). In this case, the challenge for designers is getting longer lateral lines with high values of uniformity. Objective The objective of this study was to develop a model to design longer lateral lines using non-pressure compensating drip hose. Using the developed model, the hypotheses to be evaluated were: a) the use of two different spacing between emitters in the same lateral line allows longer length; b) it is possible to get longer lateral lines using high values of pressure variation in the lateral lines since the distribution uniformity stays below allowable limits. Methodology A computer program was developed in Delphi® based on the model developed and it is able to design lateral lines in level using non-pressure compensating drip hose. The input data are: desired distribution uniformity (DU); initial and final pressure in the lateral line; coefficients of relationship between emitter discharge and pressure head; hose internal diameter; pipe cross-sectional area with the dripper; and roughness coefficient for the Hazen-Williams equation. The program allows calculate the lateral line length with three possibilities: selecting two spacing between emitters and defining the exchange point; using two pre-established spacing between emitters and calculating the length of each section with different spacing; using one emitter spacing. Results Results showed that the use of two sections with different spacing between drippers in the lateral line didn't allow longer length but got better uniformity when compared with lateral line with one spacing between emitters. The adoption of two spacing increased the flow rate per meter in the final section which represented approximately 80% of the lateral line total length and this justifies their use. The software allowed DU above 90% with pressure head variation of 40% and the use of two spacing between emitters. Conclusions The developed model/software showed to be accurate, easy to handle and useful for lateral line design using non-pressure compensating drip hose. References [1] ANDRADE, L. A. D. Estudo de uniformidade de emissão de água utilizando diferentes espaçamentos entre gotejadores na linha lateral. 2009. 87 f. Tese (Doutorado em Agronomia/Irigação e Drenagem) - Faculdade de Ciências Agronômicas, Universidade Estadual Paulista 'Julio de Mesquita Filho', Botucatu, (2009). [2] KELLER, J.; BLIESNER, R. D. Sprinkle and trickle irrigation. Caldwell: Blackburn Press, (1990). 652 p. [3] TALENS, J. A. M. Riego localizado y fertirrigacion. Madrid: Mundi-Prensa, (2002). 533 p. [4] WU, I. P. An assessment of hydraulic design of micro-irrigation systems. Agricultural Water Management, Amsterdan, v. 32, n. 3

Comparison of Mixing Characteristics for Several Fuel Injectors on an Open Plate and in a Ducted Flowpath Configuration at Hypervelocity Flow Conditions

NASA Technical Reports Server (NTRS)

Drozda, Tomasz G.; Shenoy, Rajiv R.; Passe, Bradley J.; Baurle, Robert A.; Drummond, J. Philip

2017-01-01

In order to reduce the cost and complexity associated with fuel injection and mixing experiments for high-speed flows, and to further enable optical access to the test section for nonintrusive diagnostics, the Enhanced Injection and Mixing Project (EIMP) utilizes an open flat plate configuration to characterize inert mixing properties of various fuel injectors for hypervelocity applications. The experiments also utilize reduced total temperature conditions to alleviate the need for hardware cooling. The use of "cold" flows and non-reacting mixtures for mixing experiments is not new, and has been extensively utilized as a screening technique for scramjet fuel injectors. The impact of reduced facility-air total temperature, and the use of inert fuel simulants, such as helium, on the mixing character of the flow has been assessed in previous numerical studies by the authors. Mixing performance was characterized for three different injectors: a strut, a ramp, and a flushwall. The present study focuses on the impact of using an open plate to approximate mixing in the duct. Toward this end, Reynolds-averaged simulations (RAS) were performed for the three fuel injectors in an open plate configuration and in a duct. The mixing parameters of interest, such as mixing efficiency and total pressure recovery, are then computed and compared for the two configurations. In addition to mixing efficiency and total pressure recovery, the combustion efficiency and thrust potential are also computed for the reacting simulations.

A metabolic simulator for unmanned testing of breathing apparatuses in hyperbaric conditions.

PubMed

Frånberg, Oskar; Loncar, Mario; Larsson, Åke; Ornhagen, Hans; Gennser, Mikael

2014-11-01

A major part of testing of rebreather apparatuses for underwater diving focuses on the oxygen dosage system. A metabolic simulator for testing breathing apparatuses was built and evaluated. Oxygen consumption was achieved through catalytic combustion of propene. With an admixture of carbon dioxide in the propene fuel, the system allowed the respiratory exchange ratio to be set freely within human variability and also made it possible to increase test pressures above the condensation pressure of propene. The system was tested by breathing ambient air in a pressure chamber with oxygen uptake (Vo₂) ranging from 1-4 L · min(-1), tidal volume (VT) from 1-3 L, breathing frequency (f) of 20 and 25 breaths/min, and chamber pressures from 100 to 670 kPa. The measured end-tidal oxygen concentration (Fo₂) was compared to calculated end-tidal Fo₂. The largest average difference in end-tidal Fo₂during atmospheric pressure conditions was 0.63%-points with a 0.28%-point average difference during the whole test. During hyperbaric conditions with pressures ranging from 100 to 670 kPa, the largest average difference in Fo₂was 1.68%-points seen during compression from 100 kPa to 400 kPa and the average difference in Fo₂during the whole test was 0.29%-points. In combination with a breathing simulator simulating tidal breathing, the system can be used for dynamic continuous testing of breathing equipment with changes in VT, f, Vo2, and pressure.

Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

1996-01-01

The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

The influence of age and diabetes on the skin blood flow response to local pressure.

PubMed

Petrofsky, Jerrold S; Bains, Gurinder S; Prowse, Michelle; Mc Lellan, Katie; Ethiraju, Gomathi; Lee, Scott; Gunda, Shashi; Lohman, Everett; Schwab, Ernie

2009-07-01

Previous data has shown that when pressure is applied to the skin of the ankle and on the foot, there is a reactive increase in circulation. In the present investigation, these studies were expanded to look at the response of the hand, back, and foot to applied pressure. Ten young subjects whose average age was 26.5+/-3.3 yrs, 10 older subjects whose average age was 73.3+/-19.7 yrs and 10 people with diabetes whose average age was 60.1+/-5.7 yrs participated in the study. There was no statistical difference in the height or weight of the subjects. Hemoglobin A1c of the group with Diabetes averaged 6.98+/-1.15% with the mean duration of diabetes 13.6+/-9.5 yrs. An infrared laser Doppler flow meter was used to measure circulation on the hand, lower back, and on the bottom of the foot during applications of pressure at 15, 30, 45, and 60 kPa. For all three areas of the body, circulation was significantly less in the group with diabetes than the other two groups (p<0.05). When pressure was applied at 15 kPa, the blood flow to the skin initially decreased, but then increased in the younger subjects and in the older subjects but did not increase in subjects with diabetes for any area of the body. Further, after pressure was released, for any of the four pressures examined here, while the younger subjects showed a pronounced reactive hyperemia, subjects with diabetes showed a diminished hyperemia not proportional to the pressure that was applied. It appears that the normal protective mechanism of a pressure induced hyperemia is absent or diminished in patients with diabetes with more effect on the periphery than on the core area of the body. More importantly, after pressure was applied and released, subjects with diabetes lacked a proportional hyperemia to recovery form the transient ischemia of the pressure.

Effect of blade outlet angle on radial thrust of single-blade centrifugal pump

NASA Astrophysics Data System (ADS)

Nishi, Y.; Fukutomi, J.; Fujiwara, R.

2012-11-01

Single-blade centrifugal pumps are widely used as sewage pumps. However, a large radial thrust acts on a single blade during pump operation because of the geometrical axial asymmetry of the impeller. This radial thrust causes vibrations of the pump shaft, reducing the service life of bearings and shaft seal devices. Therefore, to ensure pump reliability, it is necessary to quantitatively understand the radial thrust and clarify the behavior and generation mechanism. This study investigated the radial thrust acting on two kinds of single-blade centrifugal impellers having different blade outlet angles by experiments and computational fluid dynamics (CFD) analysis. Furthermore, the radial thrust was modeled by a combination of three components, inertia, momentum, and pressure, by applying an unsteady conservation of momentum to this impeller. As a result, the effects of the blade outlet angle on both the radial thrust and the modeled components were clarified. The total head of the impeller with a blade outlet angle of 16 degrees increases more than the impeller with a blade outlet angle of 8 degrees at a large flow rate. In this case, since the static pressure of the circumference of the impeller increases uniformly, the time-averaged value of the radial thrust of both impellers does not change at every flow rate. On the other hand, since the impeller blade loading becomes large, the fluctuation component of the radial thrust of the impeller with the blade outlet angle of 16 degrees increases. If the blade outlet angle increases, the fluctuation component of the inertia component will increase, but the time-averaged value of the inertia component is located near the origin despite changes in the flow rate. The fluctuation component of the momentum component becomes large at all flow rates. Furthermore, although the time-averaged value of the pressure component is almost constant, the fluctuation component of the pressure component becomes large at a large flow rate. In addition to the increase of the fluctuation component of this pressure component, because the fluctuation component of the inertia and momentum components becomes large (as mentioned above), the radial thrust increases at a large flow rate, as is the case for the impeller with a large blade outlet angle.

Flight Tests Results from Supersonic Deployment of an 18-Foot Diameter (5.49 meter) Towed Ballute Decelerator

NASA Technical Reports Server (NTRS)

Mayhue, Robert J.; Eckstrom, Clinton V.

1969-01-01

A ram-air-inflated, towed ballute decelerator having a maximum frontal diameter of 18 feet (5.49 meters) was deployed during free flight at a Mach number of 3.15 and a dynamic pressure of 38.5 lb/ft(exp 2) (1843.4 newtons/m(exp 2)). Deployment and extraction of the test ballute were normal but inflation stopped about 1 second after mortar firing and produced an average plateau drag force of 1500 pounds (6.7 kN) for about 1 second. Approximately 30 percent of expected total frontal area was obtained.

Pulse Wave Velocity Predicts Response to Renal Denervation in Isolated Systolic Hypertension.

PubMed

Fengler, Karl; Rommel, Karl-Philipp; Hoellriegel, Robert; Blazek, Stephan; Besler, Christian; Desch, Steffen; Schuler, Gerhard; Linke, Axel; Lurz, Philipp

2017-05-17

Renal sympathetic denervation seems to be less effective as a treatment for hypertension in patients with isolated systolic hypertension, a condition associated with elevated central arterial stiffness. Because isolated systolic hypertension can also be caused by wave reflection or increased cardiac output, a more differentiated approach might improve patient preselection for renal sympathetic denervation. We sought to evaluate the additional predictive value of invasive pulse wave velocity for response to renal sympathetic denervation in patients with combined versus isolated systolic hypertension. Patients scheduled for renal sympathetic denervation underwent additional invasive measurement of pulse wave velocity and pulse pressure before denervation. Blood pressure was assessed via ambulatory measurement at baseline and after 3 months. In total 109 patients (40 patients with isolated systolic hypertension) were included in our analysis. After 3 months, blood pressure reduction was more pronounced among patients with combined hypertension compared with patients with isolated systolic hypertension (systolic 24-hour average 9.3±10.5 versus 5.0±11.5 mm Hg, P =0.046). However, when stratifying patients with isolated systolic hypertension by invasive pulse wave velocity, patients in the lowest tertile of pulse wave velocity had comparable blood pressure reduction (12.1±12.6 mm Hg, P =0.006) despite lower baseline blood pressure than patients with combined hypertension (systolic 24-hour average 154.8±12.5 mm Hg in combined hypertension versus 141.2±8.1, 148.4±10.9, and 150.5±12.7 mm Hg, respectively, by tertiles of pulse wave velocity, P =0.002). Extended assessment of arterial stiffness can help improve patient preselection for renal sympathetic denervation and identify a subgroup of isolated systolic hypertension patients who benefit from sympathetic modulation. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Impact of anthropogenic aerosols from global, East Asian, and non-East Asian sources on East Asian summer monsoon system

NASA Astrophysics Data System (ADS)

Wang, Qiuyan; Wang, Zhili; Zhang, Hua

2017-01-01

The impact of the total effects due to anthropogenic aerosols from global, East Asian, and non-East Asian sources on East Asian summer monsoon (EASM) system is studied using an aerosol-climate online model BCC_AGCM2.0.1_CUACE/Aero. The results show that the summer mean net all-sky shortwave fluxes averaged over East Asian monsoon region (EAMR) at the top of the atmosphere (TOA) and surface reduce by 4.8 and 5.0 W m- 2, respectively, due to the increases of global aerosol emissions in 2000 relative to 1850. Changes in radiations and their resulting changes in heat and water transport and cloud fraction contribute together to the surface cooling over EAMR in summer. The increases in global anthropogenic aerosols lead to a decrease of 2.1 K in summer mean surface temperature and an increase of 0.4 hPa in summer mean surface pressure averaged over EAMR, respectively. It is shown that the changes in surface temperature and pressure are significantly larger over land than ocean, thus decreasing the contrast of land-sea surface temperature and pressure. This results in the marked anomalies of north and northeast winds over eastern and southern China and the surrounding oceans in summer, thereby weakening the EASM. The summer mean precipitation averaged over the EAMR reduces by 12%. The changes in non-East Asian aerosol emissions play a more important role in inducing the changes of local temperature and pressure, and thus significantly exacerbate the weakness of the EASM circulation due to local aerosol changes. The weakening of circulation due to both is comparable, and even the effect of non-local aerosols is larger in individual regions. The changes of local and non-local aerosols contribute comparably to the reductions in precipitation over oceans, whereas cause opposite changes over eastern China. Our results highlight the importance of aerosol changes outside East Asia in the impact of the changes of anthropogenic aerosols on EASM.

Simultaneous validation of the SunTech CT40 automated blood pressure measurement device by the 1993 British Hypertension Society protocol and the Association for the Advancement of Medical Instrumentation/International Organization for Standardization 81060-2: 2013 standard.

PubMed

Polo Friz, Hernan; Punzi, Veronica; Petri, Francesco; Orlandi, Riccardo; Maggiolini, Daniele; Polo Friz, Melisa; Primitz, Laura; Vighi, Giuseppe

2017-10-01

This study aimed to perform a simultaneous, third-party, independent validation of the oscillometric SunTech CT40 device for blood pressure (BP) measurement, according to the 1993 protocol of the British Hypertension Society and the standard of the Association for the Advancement of Medical Instrumentation (AAMI)/the International Organization for Standardization (ISO) 81060-2:2013. Patient recruitment, study procedures, and data analysis followed the recommendations stated by the protocols. The study was approved by the institutional review board. A total of 94 participants were included, 52 (55.3%) women, mean±SD age: 63.1±18.0 years, mean±SD arm circumference: 35.0±9.0 cm. The average of observers' entry BPs was 146.9±37.2 mmHg for systolic blood pressure (SBP) and 82.2±22.1 mmHg for diastolic blood pressure (DBP). Differences between the standard measurement and the test device within 5, 10, and 15 mmHg, for the better observer, were 79.4, 96.5, and 100.0% for SBP and 82.6, 97.5, and 100.0% for DBP, respectively. The mean±SD differences between the readings obtained using the test device and those obtained by the observers (AAMI/ISO 81060-2:2013 standard criterion 1) were 0.3±5.0 mmHg (SBP) and -0.8±4.3 mmHg (DBP), and the mean±SD differences between average of reference readings and average of test device readings in each patient (criterion 2) were 0.3±3.9 and -0.8±3.5 mmHg for SBP and DBP, respectively. The CT40 BP device achieved A/A grade of the British Hypertension Society protocol and fulfilled the requirements (criteria 1 and 2) of the AAMI/ISO standard. CT40 can be recommended for BP measurement in adults.

Evaluation program for secondary spacecraft cells: Initial evaluation tests of General Electric Company 40.0 ampere-hour nickel-cadmium spacecraft cells for the tracking data relay satellite system

NASA Technical Reports Server (NTRS)

Harkness, J. D.

1978-01-01

Five cells provided by NASA's Goddard Space Flight Center were evaluated at room temperature and pressure (25 C plus or minus 2 C) with discharges at the 2 hour rate. Measurements of the cell containers following test, indicated an average increase of .006 inches at the plate thickness. Average end of charge voltages and pressures, and capacity output in ampere hours were determined. Three cells exceeded the voltage requirements of 1.52 volts during both c/10 charges at 20 C. All cells exceeded the voltage requirement of 1.52 volts during the 0 C overcharge test, although their end charges were below 1.50 volts. The pressure requirement of 65 psia was exceeded by both pressure transducer cells during c/10 charges at 25 C and 20 C and also during the 0 C overcharge test. The cells with pressure transducers reached a pressure of 20 psia before reaching the voltage limit of 1.550 volts during the pressure versus capacity test, and exhibited a pressure decay of 2 psia during the last 30 minutes of the 1 hour open circuit stand. Average capacity was 51.3 ampere hours.

Root-knot nematode management in double-cropped plasticulture vegetables.

PubMed

Desaeger, J A; Csinos, A S

2006-03-01

Combination treatments of chisel-injected fumigants (methyl bromide, 1,3-D, metam sodium, and chloropicrin) on a first crop, followed by drip-applied fumigants (metam sodium and 1,3-D +/- chloropicrin) on a second crop, with and without oxamyl drip applications were evaluated for control of Meloidogyne incognita in three different tests (2002 to 2004) in Tifton, GA. First crops were eggplant or tomato, and second crops were cantaloupe, squash, or jalapeno pepper. Double-cropped vegetables suffered much greater root-knot nematode (RKN) pressure than first crops, and almost-total yield loss occurred when second crops received no nematicide treatment. On a first crop of eggplant, all fumigants provided good nematode control and average yield increases of 10% to 15 %. On second crops, higher application rates and fumigant combinations (metam sodium and 1,3-D +/- chloropicrin) improved RKN control and increased yields on average by 20% to 35 % compared to the nonfumigated control. Oxamyl increased yields of the first crop in 2003 on average by 10% to 15% but had no effect in 2004 when RKN failed to establish itself. On double-cropped squash in 2003, oxamyl following fumigation provided significant additional reduction in nematode infection and increased squash yields on average by 30% to 75%.

Increasing pressure on freshwater resources due to terrestrial feed ingredients for aquaculture production.

PubMed

Pahlow, M; van Oel, P R; Mekonnen, M M; Hoekstra, A Y

2015-12-01

As aquaculture becomes more important for feeding the growing world population, so too do the required natural resources needed to produce aquaculture feed. While there is potential to replace fish meal and fish oil with terrestrial feed ingredients, it is important to understand both the positive and negative implications of such a development. The use of feed with a large proportion of terrestrial feed may reduce the pressure on fisheries to provide feed for fish, but at the same time it may significantly increase the pressure on freshwater resources, due to water consumption and pollution in crop production for aquafeed. Here the green, blue and gray water footprint of cultured fish and crustaceans related to the production of commercial feed for the year 2008 has been determined for the major farmed species, representing 88% of total fed production. The green, blue and gray production-weighted average feed water footprints of fish and crustaceans fed commercial aquafeed are estimated at 1629 m3/t, 179 m3/t and 166 m3/t, respectively. The estimated global total water footprint of commercial aquafeed was 31-35 km3 in 2008. The top five contributors to the total water footprint of commercial feed are Nile tilapia, Grass carp, Whiteleg shrimp, Common carp and Atlantic salmon, which together have a water footprint of 18.2 km3. An analysis of alternative diets revealed that the replacement of fish meal and fish oil with terrestrial feed ingredients may further increase pressure on freshwater resources. At the same time economic consumptive water productivity may be reduced, especially for carnivorous species. The results of the present study show that, for the aquaculture sector to grow sustainably, freshwater consumption and pollution due to aquafeed need to be taken into account. Copyright © 2015. Published by Elsevier B.V.

Mean Arterial Blood Pressure Correlates with Neurological Recovery after Human Spinal Cord Injury: Analysis of High Frequency Physiologic Data

PubMed Central

Hawryluk, Gregory; Whetstone, William; Saigal, Rajiv; Ferguson, Adam; Talbott, Jason; Bresnahan, Jacqueline; Dhall, Sanjay; Pan, Jonathan; Beattie, Michael

2015-01-01

Abstract Current guidelines for the care of patients with acute spinal cord injuries (SCIs) recommend maintaining mean arterial pressure (MAP) values of 85–90 mm Hg for 7 days after an acute SCI however, little evidence supports this recommendation. We sought to better inform the relationship between MAP values and neurological recovery. A computer system automatically collected and stored q1 min physiological data from intensive care unit monitors on patients with SCI over a 6-year period. Data for 100 patients with acute SCI were collected. 74 of these patients had American Spinal Injury Association Impairment Scale (AIS) grades determined by physical examination on admission and at time of hospital discharge. Average MAP values as well as the proportion of MAP values below thresholds were explored for values from 120 mm Hg to 40 mm Hg in 1 mm Hg increments; the relationship between these measures and outcome was explored at various time points up to 30 days from the time of injury. A total of 994,875 q1 min arterial line blood pressure measurements were recorded for the included patients amid 1,688,194 min of recorded intensive care observations. A large proportion of measures were below 85 mm Hg despite generally acceptable average MAP values. Higher average MAP values correlated with improved recovery in the first 2–3 days after SCI while the proportion of MAP values below the accepted threshold of 85 mm Hg seemed a stronger correlate, decreasing in strength over the first 5–7 days after injury. This study provides strong evidence supporting a correlation between MAP values and neurological recovery. It does not, however, provide evidence of a causal relationship. Duration of hypotension may be more important than average MAP. It provides support for the notion of MAP thresholds in SCI recovery, and the highest MAP values correlated with the greatest degree of neurological recovery. The results are concordant with current guidelines in suggesting that MAP thresholds >85 mm Hg may be appropriate after acute SCI. PMID:25669633

Surface pressure distributions on a delta wing undergoing large amplitude pitching oscillations. M.S. Thesis

NASA Technical Reports Server (NTRS)

Thompson, Scott A.

1989-01-01

Wind tunnel experiments were performed on a 70 deg sweep delta wing to determine the effect of a sinusoidal pitching motion on the pressure field on the suction side of the wing. Twelve pressure taps were placed from 35 to 90 percent of the chord, at 60 percent of the local semi-span. Pressure coefficients were measured as a function of Reynolds number and pitch rate. The pressure coefficient was seen to vary at approximately the same frequency as the pitching frequency. The relative pressure variation at each chord location was comparable for each case. The average pressure distribution through each periodic motion was near the static distribution for the average angle of attack. Upon comparing the upstroke and downstroke pressures for a specific angle of attack, the downstroke pressures were slightly larger. Vortex breakdown was seen to have the most significant effect at the 40 to 45 percent chord location, where a decrease in pressure was apparent.

Sufficient condition for a finite-time singularity in a high-symmetry Euler flow: Analysis and statistics

NASA Astrophysics Data System (ADS)

Ng, C. S.; Bhattacharjee, A.

1996-08-01

A sufficient condition is obtained for the development of a finite-time singularity in a highly symmetric Euler flow, first proposed by Kida [J. Phys. Soc. Jpn. 54, 2132 (1995)] and recently simulated by Boratav and Pelz [Phys. Fluids 6, 2757 (1994)]. It is shown that if the second-order spatial derivative of the pressure (pxx) is positive following a Lagrangian element (on the x axis), then a finite-time singularity must occur. Under some assumptions, this Lagrangian sufficient condition can be reduced to an Eulerian sufficient condition which requires that the fourth-order spatial derivative of the pressure (pxxxx) at the origin be positive for all times leading up to the singularity. Analytical as well as direct numerical evaluation over a large ensemble of initial conditions demonstrate that for fixed total energy, pxxxx is predominantly positive with the average value growing with the numbers of modes.

The gust-mitigating potential of flapping wings.

PubMed

Fisher, Alex; Ravi, Sridhar; Watkins, Simon; Watmuff, Jon; Wang, Chun; Liu, Hao; Petersen, Phred

2016-08-02

Nature's flapping-wing flyers are adept at negotiating highly turbulent flows across a wide range of scales. This is in part due to their ability to quickly detect and counterract disturbances to their flight path, but may also be assisted by an inherent aerodynamic property of flapping wings. In this study, we subject a mechanical flapping wing to replicated atmospheric turbulence across a range of flapping frequencies and turbulence intensities. By means of flow visualization and surface pressure measurements, we determine the salient effects of large-scale freestream turbulence on the flow field, and on the phase-average and fluctuating components of pressure and lift. It is shown that at lower flapping frequencies, turbulence dominates the instantaneous flow field, and the random fluctuating component of lift contributes significantly to the total lift. At higher flapping frequencies, kinematic forcing begins to dominate and the flow field becomes more consistent from cycle to cycle. Turbulence still modulates the flapping-induced flow field, as evidenced in particular by a variation in the timing and extent of leading edge vortex formation during the early downstroke. The random fluctuating component of lift contributes less to the total lift at these frequencies, providing evidence that flapping wings do indeed provide some inherent gust mitigation.

Numerical investigation of drag and heat flux reduction mechanism of the pulsed counterflowing jet on a blunt body in supersonic flows

NASA Astrophysics Data System (ADS)

Zhang, Rui-rui; Huang, Wei; Yan, Li; Li, Lang-quan; Li, Shi-bin; Moradi, R.

2018-05-01

To design a kind of aerospace vehicle, the drag and heat flux reduction are the most important factors. In the current study, the counterflowing jet, one of the effective drag and heat flux reduction concepts, is investigated numerically by the two-dimensional axisymmetric Reynolds-averaged Navier-Stokes equations coupled with the SST k-ω turbulence model. An axisymmetric numerical simulation mode of the counterflowing jet on the supersonic vehicle nose-tip is established, and the numerical method employed is validated by the experimental schlieren images and experimental data in the open literature. A pulsed counterflowing jet scheme is proposed, and it uses a sinusoidal function to control the total and static pressures of the counterflowing jet. The obtained results show that the long penetration mode does not exist in the whole turnaround, even in a relatively small range of the jet total and static pressures, and this is different from the phenomenon obtained under the steady condition in the open literature. At the same time, it is observed that the variation of the physical parameters, such as the Stanton number induced by the pulsed jet, has an obvious periodicity and hysteresis phenomenon.

Assessment of vital exhaustion and identification of subjects at increased risk of myocardial infarction in general practice.

PubMed

Schuitemaker, G E; Dinant, G J; van der Pol, G A; Appels, A

2004-01-01

Vital exhaustion, a state characterized by unusual fatigue, loss of energy, increased irritability, and feelings of demoralization, is one of the cardiovascular risk factors. The authors investigated whether vital exhaustion contributes to the identification of subjects at increased risk of myocardial infarction in general practice. In this prospective cohort study, vital exhaustion was assessed with the Maastricht Interview on Vital Exhaustion. Other cardiovascular risk factors established were age, gender, systolic and diastolic blood pressure, total cholesterol, body mass index, smoking habits, cardiovascular disease, and diabetes mellitus. A Cox regression analysis was used. The subjects were adults (41-66 years) in an average Dutch village population. Outcome measures were fatal and nonfatal myocardial infarction. At the univariate level, vital exhaustion doubled the risk of myocardial infarction. The effect of exhaustion was confounded by gender; women had higher exhaustion scores and a lower incidence of myocardial infarction. With control for gender, age, systolic blood pressure, total cholesterol, smoking habits, self-reported cardiovascular disease, and diabetes mellitus, vital exhaustion almost tripled the risk of myocardial infarction. Assessment of vital exhaustion contributes to the identification of subjects at increased risk of myocardial infarction in general practice.

Damping, amplitude, aging tests of stacked transducers for shock wave generation.

PubMed

Sferruzza, Jean-Pierre; Birer, Alain; Chavrier, Françoise; Cathignol, Dominique

2002-10-01

New clinical concepts in lithotripsy demand small shock heads. Reducing the size of piezoelectric shock heads will be possible only if the pressure generated at the surface of each transducer can be increased so that the total pressure at the focus remains the same. To solve this problem, different solutions were proposed. For example, it has been demonstrated that piezocomposite material, as opposed to piezoceramic material, allows the generation of a higher surface pressure before breaking, mainly because radial modes are dramatically reduced. In addition, in a previous paper, we showed the feasibility of generating high-pressure pulse waves without increasing the transducer voltage by using sandwiched transducers, which are a stack of two or more transducers. Some discrepancies appeared, however, between the pressure measured at the surface of the front transducer and the arithmetic sum of the pressures generated by each transducer constituting the stack. In fact, development of such stacked transducers capable of generating surface pressures in the range of 2 to 5 MPa is very complex, which may explain why no aging tests have been reported in the literature thus far. In the first part of this paper, we theoretically determine the importance of the electroacoustical coupling between the two transducers on the generated surface pressure. We show that pressure losses due to these electroacoustical couplings are less than 5%. Experimental measurements done on a stacked transducer assembled and tightened in a castor oil-filled tank are in excellent accordance with the theoretical measurements. Using this assembly technique, it was possible to obtain, on average, out of four elements, a pressure of 7.5 MPa for the duration of 4 million shocks, which would allow the treatment of approximately 1000 patients.

Control of respiration-driven retrograde flow in the subdiaphragmatic venous return of the Fontan circulation

PubMed Central

Vukicevic, M; Conover, T; Jaeggli, M; Zhou, J; Pennati, G; Hsia, TY; Figliola, RS

2014-01-01

Respiration influences the subdiaphragmatic venous return in the total cavopulmonary connection (TCPC) of the Fontan circulation whereby both the inferior vena cava (IVC) and hepatic vein flows can experience retrograde motion. Controlling retrograde flows could improve patient outcomes. Using a patient-specific model within a Fontan mock circulatory system with respiration, we inserted a valve into the IVC to examine its effects on local hemodynamics while varying retrograde volumes by changing vascular impedances. A bovine valved conduit reduced IVC retrograde flow to within 3% of antegrade flow in all cases. The valve closed only under conditions supporting retrograde flow and its effects on local hemodynamics increased with larger retrograde volume. Liver and TCPC pressures improved only while the valve leaflets were closed while cycle-averaged pressures improved only slightly (italic>1 mm Hg). Increased pulmonary vascular resistance raised mean circulation pressures but the valve functioned and cardiac output improved and stabilized. Power loss across the TCPC improved by 12–15% (pbold>0.05) with a valve. The effectiveness of valve therapy is dependent on patient vascular impedance. PMID:24814833

Structure of magnetopause layers formed by a radial interplanetary magnetic field

NASA Astrophysics Data System (ADS)

Safrankova, Jana; Simunek, Jiri; Nemecek, Zdenek; Prech, Lubomir; Grygorov, Kostiantyn; Shue, Jih-Hong; Samsonov, Andrey; Pi, Gilbert

2016-07-01

The magnetopause location is generally believed to be determined by the solar wind dynamic pressure and by the sign and value of the interplanetary magnetic field (IMF) vertical (Bz) component. A contribution of other parameters is usually assumed to be minor or negligible near the equatorial plane. However, recent papers have shown a magnetopause expansion during intervals of a nearly radial IMF (large IMF Bx component). Under such conditions, the total pressure exerted on the subsolar magnetopause is significantly lower than the solar wind dynamic pressure as demonstrate both MHD simulations and statistical investigations. During a long-duration radial IMF, all parameters - the IMF magnitude, solar wind speed, density, and especially the temperature are depressed in comparison with their yearly averages. Moreover, in this case, the structures of the LLBL change; the LLBL shows different profiles at both hemispheres for negative and positive IMF Bx polarities. This asymmetry changes over time and influences the LLBL structures due to magnetic reconnection. We present an overview of important physical quantities controlling the magnetopause compression and new results that deal with the structure of the magnetopause and adjacent layers.

STME Hydrogen Mixer Study

NASA Technical Reports Server (NTRS)

Blumenthal, Rob; Kim, Dongmoon; Bache, George

1992-01-01

The hydrogen mixer for the Space Transportation Main Engine is used to mix cold hydrogen bypass flow with warm hydrogen coolant chamber gas, which is then fed to the injectors. It is very important to have a uniform fuel temperature at the injectors in order to minimize mixture ratio problems due to the fuel density variations. In addition, the fuel at the injector has certain total pressure requirements. In order to achieve these objectives, the hydrogen mixer must provide a thoroughly mixed fluid with a minimum pressure loss. The AEROVISC computational fluid dynamics (CFD) code was used to analyze the STME hydrogen mixer, and proved to be an effective tool in optimizing the mixer design. AEROVISC, which solves the Reynolds Stress-Averaged Navier-Stokes equations in primitive variable form, was used to assess the effectiveness of different mixer designs. Through a parametric study of mixer design variables, an optimal design was selected which minimized mixed fuel temperature variation and fuel mixer pressure loss. The use of CFD in the design process of the STME hydrogen mixer was effective in achieving an optimal mixer design while reducing the amount of hardware testing.

The effects of blood pressure reduction in older patients: an overview of five randomized controlled trials in elderly hypertensives.

PubMed

MacMahon, S; Rodgers, A

1993-11-01

Direct evidence about the effects of antihypertensive treatment on vascular disease in older patients is available from five randomized trials conducted exclusively in patients over the age of 60 years. These trials involved a total of 12,483 individuals with systolic or diastolic hypertension (mean age = 72 years, mean entry blood pressure = 181/88 mmHg). Over an average follow-up period of 4.7 years, a 15/6 mmHg difference in blood pressure between study and control groups was achieved. Among those patients assigned active treatment, stroke incidence was reduced by 34% SD6 and coronary heart disease incidence was reduced by 19% SD7. These proportional reductions were of similar size to those observed in trials in predominantly younger patients. However, the absolute benefits observed in older patients were more than twice as great as those observed in younger patients. The results suggest that over 10 years, treatment would prevent at least one major vascular event among every 10 elderly patients at similar risk to those enrolled in the trials.

Inlet Trade Study for a Low-Boom Aircraft Demonstrator

NASA Technical Reports Server (NTRS)

Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

2016-01-01

Propulsion integration for low-boom supersonic aircraft requires careful inlet selection, placement, and tailoring to achieve acceptable propulsive and aerodynamic performance, without compromising vehicle sonic boom loudness levels. In this investigation, an inward-turning streamline-traced and axisymmetric spike inlet are designed and independently installed on a conceptual low-boom supersonic demonstrator aircraft. The airframe was pre-shaped to achieve a target ground under-track loudness of 76.4 PLdB at cruise using an adjoint-based design optimization process. Aircraft and inlet performance characteristics were obtained by solution of the steady-state Reynolds-averaged Navier-Stokes equations. Isolated cruise inlet performance including total pressure recovery and distortion were computed and compared against installed inlet performance metrics. Evaluation of vehicle near-field pressure signatures, along with under- and off-track propagated loudness levels is also reported. Results indicate the integrated axisymmetric spike design offers higher inlet pressure recovery, lower fan distortion, and reduced sonic boom. The vehicle with streamline-traced inlet exhibits lower external wave drag, which translates to a higher lift-to-drag ratio and increased range capability.

Computational and Experimental Characterization of the Mach 6 Facility Nozzle Flow for the Enhanced Injection and Mixing Project at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Drozda, Tomasz G.; Cabell, Karen F.; Passe, Bradley J.; Baurle, Robert A.

2017-01-01

Computational fluid dynamics analyses and experimental data are presented for the Mach 6 facility nozzle used in the Arc-Heated Scramjet Test Facility for the Enhanced Injection and Mixing Project (EIMP). This project, conducted at the NASA Langley Research Center, aims to investigate supersonic combustion ramjet (scramjet) fuel injection and mixing physics relevant to flight Mach numbers greater than 8. The EIMP experiments use a two-dimensional Mach 6 facility nozzle to provide the high-speed air simulating the combustor entrance flow of a scramjet engine. Of interest are the physical extent and the thermodynamic properties of the core flow at the nozzle exit plane. The detailed characterization of this flow is obtained from three-dimensional, viscous, Reynolds-averaged simulations. Thermodynamic nonequilibrium effects are also investigated. The simulations are compared with the available experimental data, which includes wall static pressures as well as in-stream static pressure, pitot pressure and total temperature obtained via in-stream probes positioned just downstream of the nozzle exit plane.

Atmospheric Pressure and Onset of Episodes of Menière's Disease - A Repeated Measures Study.

PubMed

Gürkov, Robert; Strobl, Ralf; Heinlin, Nina; Krause, Eike; Olzowy, Bernhard; Koppe, Christina; Grill, Eva

2016-01-01

External changes of air pressure are transmitted to the middle and inner ear and may be used therapeutically in Menière's disease, one of the most common vertigo disorders. We analyzed the possible relationship of atmospheric pressure and other meteorological parameters with the onset of MD vertigo episodes in order to determine whether atmospheric pressure changes play a role in the occurrence of MD episodes. Patients of a tertiary outpatient dizziness clinic diagnosed with MD were asked to keep a daily vertigo diary to document MD episodes (2004-2009). Local air pressure, absolute temperature and dew point temperature were acquired on an hourly basis. Change in meteorological parameters was conceptualized as the maximum difference in a 24 hour time frame preceding each day. Effects were estimated using additive mixed models with a random participant effect. We included lagged air parameters, age, sex, weekday and season in the model. A total of 56 persons (59% female) with mean age 54 years were included. Mean follow-up time was 267 days. Persons experienced on average 10.3 episodes during the observation period (median 8). Age and change in air pressure were significantly associated with vertigo onset risk (Odds Ratio = 0.979 and 1.010). We could not show an effect of sex, weekday, season, air temperature, and dew point temperature. Change in air pressure was significantly associated with onset of MD episodes, suggesting a potential triggering mechanism in the inner ear. MD patients may possibly use air pressure changes as an early warning system for vertigo attacks in the future.

Influence of Microgravity on Arterial Baroreflex Responses Triggered by Valsalva's Maneuver

NASA Technical Reports Server (NTRS)

Eckberg, Dwain L.; Cox, James F.; Tahvanainen, Kari U. O.; Kuusela, Tom A.; Cooke, William H.; Ames, Jimey E.

2003-01-01

When astronauts return to Earth and stand upright, their heart rates may speed inordinately, their blood pressures may fall, and some returning astronauts may even faint. Since physiological adjustments to standing are mediated importantly by pressure-regulating reflexes (baroreflexes), we studied involuntary (or autonomic) nerve and blood pressure responses of astronauts to four, 15-second periods of 15- and 30-mmHg straining (Valsalva'. maneuver). We measured the electrocardiogram, finger blood pressure, respiration, and muscle sympathetic nerve activity in four healthy male astronauts before and during the 16-day Neurolab Space Shuttle mission. We found that although microgravity provoked major autonomic changes, no astronaut experienced fainting symptoms after the mission. Blood pressure fell more during straining in space than on Earth (the average reduction of systolic pressure with 30-mmHg straining was 49 mmHg during and 27 mmHg before the mission). However, the increases of muscle sympathetic nerve activity that were triggered by straining were also larger in space than on Earth. As a result, the gain of the sympathetic baroreflex, taken as the total sympathetic nerve response divided by the maximum pressure reduction during straining, was the same in space as on Earth. In contrast, heart rate changes, which are mediated by changes of vagus nerve activity, were smaller in space. This and earlier research suggest that exposure to microgravity augments blood pressure and sympathetic adjustments to Valsalva straining and differentially reduces vagal, but not sympathetic baroreflex responsiveness. The changes that we documented can be explained economically as a consequence of the blood volume reduction that occurs in space.

Controlling and assessing pressure conditions during treatment of tar sands formations

DOEpatents

Zhang, Etuan; Beer, Gary Lee

2015-11-10

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the tar sands formation from a plurality of heaters located in the formation. Heat is allowed to transfer from the heaters to at least a portion of the formation. A pressure in the portion of the formation is controlled such that the pressure remains below a fracture pressure of the formation overburden while allowing the portion of the formation to heat to a selected average temperature of at least about 280.degree. C. and at most about 300.degree. C. The pressure in the portion of the formation is reduced to a selected pressure after the portion of the formation reaches the selected average temperature.

Evaluation of Hearing Loss in Pilots

PubMed Central

Atalay, Hayriye; Babakurban, Seda Türkoğlu; Aydın, Erdinç

2015-01-01

Objective High-intensity noise sources with an increase in air traffic and sudden changes in atmospheric pressure can cause hearing loss in pilots. The main goal of this research is to examine hearing loss due to age, the total flight hours and aircraft types and to evaluate the effects of personal conditions that can influence the hearing level. Methods We examined the data of 234 Turkish pilots aged between 25 and 54 years who were examined due to the aviation Law for annual control from January 2005 to January 2014 at Başkent University Medical Faculty, Ankara Hospital. The audiometric results of the pilots were used. While 1, 2, 3, 4, 6, and 8 KHz were used for the airway threshold, 1, 2, and 4 KHz were used for the bone conduction threshold. Results According to the data of the 234 pilots, there was a significant correlation between high-frequency hearing loss and the total flight hours and pilots’ ages. The average hearing loss was higher, particularly in the left ear, in pilots using helicopters than in those using other aircraft types. There was no statistically significant correlation between hearing loss and diabetes, hypercholesterolemia, high blood pressure, anemia, obesity, and smoking. Conclusion A significant correlation was observed between high frequency hearing loss and the total flight hours, pilots’ age, and aircraft types in our study. PMID:29392000

Auxiliary total artificial heart: A compact electromechanical artificial heart working simultaneously with the natural heart.

PubMed

Andrade, A; Nicolosi, D; Lucchi, J; Biscegli, J; Arruda, A C; Ohashi, Y; Mueller, J; Tayama, E; Glueck, J; Nosé, Y

1999-09-01

Leading international institutions are designing and developing various types of ventricular assist devices (VAD) and total artificial hearts (TAH). Some of the commercially available pulsatile VADs are not readily implantable into the thoracic cavity of smaller size patients because of size limitation. The majority of the TAH dimensions requires the removal of the patients' native heart. A miniaturized artificial heart, the auxiliary total artificial heart (ATAH), is being developed in these authors' laboratories. This device is an electromechanically driven ATAH using a brushless direct current (DC) motor fixed in a center metallic piece. This pusher plate-type ATAH control is based on Frank-Starling's law. The beating frequency is regulated through the change of the left preload, assisting the native heart in obtaining adequate blood flow. With the miniaturization of this pump, the average sized patient can have the surgical implantation procedure in the right thoracic cavity without removing the native heart. The left and right stroke volumes are 35 and 32 ml, respectively. In vitro tests were conducted, and the performance curves demonstrate that the ATAH produces 5 L/min of cardiac output at 180 bpm (10 mmHg of left inlet mean pressure and 100 mm Hg of left outlet mean pressure). Taking into account that this ATAH is working along with the native heart, this output is more than satisfactory for such a device.

Spatio-temporal variability of lake CH4 fluxes and its influence on annual estimates

NASA Astrophysics Data System (ADS)

Natchimuthu, S.; Sundgren, I.; Gålfalk, M.; Klemedtsson, L.; Crill, P. M.; Danielsson, Å.; Bastviken, D.

2014-12-01

Lakes are major sources of methane (CH4) to the atmosphere and it has been shown that lakes contribute significantly to the global CH4 budget. However, the data behind these global estimates are snapshots in time and space only and they typically lack information on spatial and temporal variability of fluxes which can potentially lead to biased estimates. Recent studies have shown that diffusive flux, gas exchange velocity (k), ebullition and concentration of CH4 in the surface water can vary significantly in space within lakes. CH4 fluxes can also change at a broad range of temporal scales in response to seasons, temperature, lake mixing events, short term weather events like pressure variations, shifting winds and diel cycles. We sampled CH4 fluxes and surface water concentrations from three lakes of differing characteristics in southwest Sweden over two annual cycles, approximately every 14 days from April to October 2012 and from April to November 2013. CH4 fluxes were measured using floating chambers distributed in the lakes based on depth categories and dissolved CH4 concentrations were determined by a headspace equilibration method. We observed significant differences in CH4 concentration, diffusion, ebullition and total fluxes between and within the lakes. The fluxes increased exponentially with temperature in all three lakes and water temperature, for example, explained 53-78% of variations in total fluxes in the lakes. Based on our data which relied on improved spatial and temporal information, we demonstrate that measurements which do not take into account of the spatial variability in the lakes could substantially bias the whole lake estimates. For instance, in one of the lakes, measurements from the central parts of the lake represented only 58% of our estimates from all chambers on an average. In addition, we consider how intensive sampling in one season of the year may affect the annual estimates due to the complex interaction of temperature, air pressure and lake mixing events on CH4 fluxes. For example, samples collected when the average air temperatures during chamber deployments were above 15 °C overestimated the total fluxes by 17-157% in all lakes when compared to averages from all measurement times.

Optimized nested Markov chain Monte Carlo sampling: theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coe, Joshua D; Shaw, M Sam; Sewell, Thomas D

2009-01-01

Metropolis Monte Carlo sampling of a reference potential is used to build a Markov chain in the isothermal-isobaric ensemble. At the endpoints of the chain, the energy is reevaluated at a different level of approximation (the 'full' energy) and a composite move encompassing all of the intervening steps is accepted on the basis of a modified Metropolis criterion. By manipulating the thermodynamic variables characterizing the reference system we maximize the average acceptance probability of composite moves, lengthening significantly the random walk made between consecutive evaluations of the full energy at a fixed acceptance probability. This provides maximally decorrelated samples ofmore » the full potential, thereby lowering the total number required to build ensemble averages of a given variance. The efficiency of the method is illustrated using model potentials appropriate to molecular fluids at high pressure. Implications for ab initio or density functional theory (DFT) treatment are discussed.« less

Application of a low cost ceramic filter to a membrane bioreactor for greywater treatment.

PubMed

Hasan, Md Mahmudul; Shafiquzzaman, Md; Nakajima, Jun; Ahmed, Abdel Kader T; Azam, Mohammad Shafiul

2015-03-01

The performance of a low cost and simple ceramic filter to a membrane bioreactor (MBR) process was evaluated for greywater treatment. The ceramic filter was submerged in an acrylic cylindrical column bioreactor. Synthetic greywater (prepared by shampoo, dish cleaner and laundry detergent) was fed continuously into the reactor. The filter effluent was obtained by gravitational pressure. The average flux performance was observed to be 11.5 LMH with an average hydraulic retention time of 1.7 days. Complete biodegradation of surfactant (methylene blue active substance removal: 99-100%) as well as high organic removal performance (biochemical oxygen demand: 97-100% and total organic carbon: >88%) was obtained. The consistency of flux (11.5 LMH) indicated that the filter can be operated for a long time without fouling. The application of this simple ceramic filter would make MBR technology cost-effective in developing countries for greywater reclamation and reuse.

Gender affects sympathetic and hemodynamic response to postural stress

NASA Technical Reports Server (NTRS)

Shoemaker, J. K.; Hogeman, C. S.; Khan, M.; Kimmerly, D. S.; Sinoway, L. I.

2001-01-01

We tested the hypothesis that differences in sympathetic reflex responses to head-up tilt (HUT) between males (n = 9) and females (n = 8) were associated with decrements in postural vasomotor responses in women. Muscle sympathetic nerve activity (MSNA; microneurography), heart rate, stroke volume (SV; Doppler), and blood pressure (Finapres) were measured during a progressive HUT protocol (5 min at each of supine, 20 degrees, 40 degrees, and 60 degrees ). MSNA and hemodynamic responses were also measured during the cold pressor test (CPT) to examine nonbaroreflex neurovascular control. SV was normalized to body surface area (SV(i)) to calculate the index of cardiac output (Q(i)), and total peripheral resistance (TPR). During HUT, heart rate increased more in females versus males (P < 0.001) and SV(i) and Q(i) decreased similarly in both groups. Mean arterial pressure (MAP) increased to a lesser extent in females versus males in the HUT (P < 0.01) but increases in TPR during HUT were similar. MSNA burst frequency was lower in females versus males in supine (P < 0.03) but increased similarly during HUT. Average amplitude/burst increased in 60 degrees HUT for males but not females. Both males and females demonstrated an increase in MAP as well as MSNA burst frequency, mean burst amplitude, and total MSNA during the CPT. However, compared with females, males demonstrated a greater neural response (DeltaTotal MSNA) due to a larger increase in mean burst amplitude (P < 0.05). Therefore, these data point to gender-specific autonomic responses to cardiovascular stress. The different MSNA response to postural stress between genders may contribute importantly to decrements in blood pressure control during HUT in females.

Effect of Degeneration on Fluid-Solid Interaction within Intervertebral Disk Under Cyclic Loading - A Meta-Model Analysis of Finite Element Simulations.

PubMed

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid-solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk.

Effect of Degeneration on Fluid–Solid Interaction within Intervertebral Disk Under Cyclic Loading – A Meta-Model Analysis of Finite Element Simulations

PubMed Central

Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

2015-01-01

The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid–fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid–solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid–fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk. PMID:25674562

Analysis of a Shock-Associated Noise Prediction Model Using Measured Jet Far-Field Noise Data

NASA Technical Reports Server (NTRS)

Dahl, Milo D.; Sharpe, Jacob A.

2014-01-01

A code for predicting supersonic jet broadband shock-associated noise was assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. The jet was operated at 24 conditions covering six fully expanded Mach numbers with four total temperature ratios. To enable comparisons of the predicted shock-associated noise component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise component spectra. Comparisons between predicted and measured shock-associated noise component spectra were used to identify deficiencies in the prediction model. Proposed revisions to the model, based on a study of the overall sound pressure levels for the shock-associated noise component of the measured data, a sensitivity analysis of the model parameters with emphasis on the definition of the convection velocity parameter, and a least-squares fit of the predicted to the measured shock-associated noise component spectra, resulted in a new definition for the source strength spectrum in the model. An error analysis showed that the average error in the predicted spectra was reduced by as much as 3.5 dB for the revised model relative to the average error for the original model.

[Distribution features of chlorophyll a and primary productivity in high frequency area of red tide in East China Sea during spring].

PubMed

Zhou, Weihua; Huo, Wenyi; Yuan, Xiangcheng; Yin, Kedong

2003-07-01

The distributions of chlorophyll a and primary productivity were determined during April to May 2002 in the East China Sea. The results showed that the average concentration of chlorophyll a was 1.086 mg.m-3 at surface layer, and that nano- and pico-phytoplankton (< 20 microns) dominated the phytoplankton biomass in this sea region during Spring (up to 64% of total chlorophyll a content). Ultra-phytoplankton (< 5 microns) consisted 27% of total phytoplankton biomass. Nutrients and feeding pressure of zooplankton affected the distribution of chlorophyll a and its size-fractionation. The average primary productivity was 10.091 mg.m-3.h-1, while that of red tide tracking stations R-03, RL-01 and RG-01 was 399.984 mg.m-3.h-1. Light and nutrients were the main factors affecting the distributions of chlorophyll a and primary productivity. The station DC-11 had a high concentration of phytoplankton biomass. The surface layer concentration of chlorophyll a and primary productivity were up to 9,082 mg.m-3 and 128,79 mg.m-3.h-1, respectively, but the color of the seawater was normal.

Characteristics of an immobilized yeast cell system using very high gravity for the fermentation of ethanol.

PubMed

Ji, Hairui; Yu, Jianliang; Zhang, Xu; Tan, Tianwei

2012-09-01

The characteristics of ethanol production by immobilized yeast cells were investigated for both repeated batch fermentation and continuous fermentation. With an initial sugar concentration of 280 g/L during the repeated batch fermentation, more than 98% of total sugar was consumed in 65 h with an average ethanol concentration and ethanol yield of 130.12 g/L and 0.477 g ethanol/g consumed sugar, respectively. The immobilized yeast cell system was reliable for at least 10 batches and for a period of 28 days without accompanying the regeneration of Saccharomyces cerevisiae inside the carriers. The multistage continuous fermentation was carried out in a five-stage column bioreactor with a total working volume of 3.75 L. The bioreactor was operated for 26 days at a dilution rate of 0.015 h(-1). The ethanol concentration of the effluent reached 130.77 g/L ethanol while an average 8.18 g/L residual sugar remained. Due to the high osmotic pressure and toxic ethanol, considerable yeast cells died without regeneration, especially in the last two stages, which led to the breakdown of the whole system of multistage continuous fermentation.

The influence of weather on Golden Eagle migration in northwestern Montana

USGS Publications Warehouse

Yates, R.E.; McClelland, B.R.; Mcclelland, P.T.; Key, C.H.; Bennetts, R.E.

2001-01-01

We analyzed the influence of 17 weather factors on migrating Golden Eagles (Aquila chrysaetos) near the Continental Divide in Glacier National Park, Montana, U.S.A. Local weather measurements were recorded at automated stations on the flanks of two peaks within the migration path. During a total of 506 hr of observation, the yearly number of Golden Eagles in autumn counts (1994-96) averaged 1973; spring counts (1995 and 1996) averaged 605 eagles. Mean passage rates (eagles/hr) were 16.5 in autumn and 8.2 in spring. Maximum rates were 137 in autumn and 67 in spring. Using generalized linear modeling, we tested for the effects of weather factors on the number of eagles counted. In the autumn model, the number of eagles increased with increasing air temperature, rising barometric pressure, decreasing relative humidity, and interactions among those factors. In the spring model, the number of eagles increased with increasing wind speed, barometric pressure, and the interaction between these factors. Our data suggest that a complex interaction among weather factors influenced the number of eagles passing on a given day. We hypothesize that in complex landscapes with high topographic relief, such as Glacier National Park, numerous weather factors produce different daily combinations to which migrating eagles respond opportunistically. ?? 2001 The Raptor Research Foundation, Inc.

A Priori Analysis of Flamelet-Based Modeling for a Dual-Mode Scramjet Combustor

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; McDaniel, James C.; Drozda, Tomasz G.; Lacaze, Guilhem; Oefelein, Joseph

2014-01-01

An a priori investigation of the applicability of flamelet-based combustion models to dual-mode scramjet combustion was performed utilizing Reynolds-averaged simulations (RAS). For this purpose, the HIFiRE Direct Connect Rig (HDCR) flowpath, fueled with a JP-7 fuel surrogate and operating in dual- and scram-mode was considered. The chemistry of the JP-7 fuel surrogate was modeled using a 22 species, 18-step chemical reaction mechanism. Simulation results were compared to experimentally-obtained, time-averaged, wall pressure measurements to validate the RAS solutions. The analysis of the dual-mode operation of this flowpath showed regions of predominately non-premixed, high-Damkohler number, combustion. Regions of premixed combustion were also present but associated with only a small fraction of the total heat-release in the flow. This is in contrast to the scram-mode operation, where a comparable amount of heat is released from non-premixed and premixed combustion modes. Representative flamelet boundary conditions were estimated by analyzing probability density functions for temperature and pressure for pure fuel and oxidizer conditions. The results of the present study reveal the potential for a flamelet model to accurately model the combustion processes in the HDCR and likely other high-speed flowpaths of engineering interest.

Two-Dimensional Supersonic Nozzle Thrust Vectoring Using Staggered Ramps

NASA Astrophysics Data System (ADS)

Montes, Carlos Fernando

A novel mechanism for vectoring the thrust of a supersonic, air-breathing engine was analyzed numerically using ANSYS Fluent. The mechanism uses two asymmetrically staggered ramps; one placed at the throat, the other positioned at the exit lip of the nozzle. The nozzle was designed using published flow data, isentropic relationships, and piecewise quartic splines. The design was verified numerically and was in fair agreement with the analytical data. Using the steady-state pressure-based solver, along with the realizable kappa - epsilon turbulence model, a total of eighteen simulations were conducted: three ramp lengths at three angles, using two sets of inlet boundary conditions (non-afterburning and afterburning). The vectoring simulations showed that the afterburning flow yields a lower flow deflection distribution, shown by the calculated average deflection angle and area-weighted integrals of the distributions. The data implies that an aircraft can achieve an average thrust vectoring angle of approximately 30° in a given direction with the longest ramp length and largest ramp angle configuration. With increasing ramp angle, the static pressure across the nozzle inlet increased, causing concern for potential negative effects on the engine's turbine. The mechanism, for which a provisional patent application has been filed, will require further work to investigate the maximum possible thrust vectoring angle, including experiments.

Respiratory sinus arrhythmia: time domain characterization using autoregressive moving average analysis

NASA Technical Reports Server (NTRS)

Triedman, J. K.; Perrott, M. H.; Cohen, R. J.; Saul, J. P.

1995-01-01

Fourier-based techniques are mathematically noncausal and are therefore limited in their application to feedback-containing systems, such as the cardiovascular system. In this study, a mathematically causal time domain technique, autoregressive moving average (ARMA) analysis, was used to parameterize the relations of respiration and arterial blood pressure to heart rate in eight humans before and during total cardiac autonomic blockade. Impulse-response curves thus generated showed the relation of respiration to heart rate to be characterized by an immediate increase in heart rate of 9.1 +/- 1.8 beats.min-1.l-1, followed by a transient mild decrease in heart rate to -1.2 +/- 0.5 beats.min-1.l-1 below baseline. The relation of blood pressure to heart rate was characterized by a slower decrease in heart rate of -0.5 +/- 0.1 beats.min-1.mmHg-1, followed by a gradual return to baseline. Both of these relations nearly disappeared after autonomic blockade, indicating autonomic mediation. Maximum values obtained from the respiration to heart rate impulse responses were also well correlated with frequency domain measures of high-frequency "vagal" heart rate control (r = 0.88). ARMA analysis may be useful as a time domain representation of autonomic heart rate control for cardiovascular modeling.

Comparison of high-pressure liquid chromatography and microbiological assay for the determination of biliary elimination of ciprofloxacin in humans.

PubMed Central

Brogard, J M; Jehl, F; Monteil, H; Adloff, M; Blickle, J F; Levy, P

1985-01-01

Serum kinetics and biliary, urinary, and fecal elimination of ciprofloxacin, a new quinolone derivative, were studied in 12 recently cholecystectomized patients provided with T-tube drainage during 24 h after oral administration of a single 500-mg dose of this substance. Drug concentrations were measured by both high-pressure liquid chromatography (HPLC) and microbiological assay. The results were comparable for the concentrations in serum (average of peaks, 2.0 +/- 0.2 micrograms/ml by HPLC and 2.3 +/- 0.3 micrograms/ml by the microbiological method) and urine (0 to 6 h, 267 +/- 74 and 241 +/- 58 micrograms/ml, respectively). This was not the case for biliary values, for which the microbiological assay yielded significantly higher concentrations than did HPLC (average of peak concentrations, 21.2 +/- 2.6 and 16.0 +/- 2.5 micrograms/ml, respectively [P less than 0.02]), nor for total 24-h biliary output (2,167 +/- 288 and 1,587 +/- 222 micrograms, respectively [P less than 0.01]). This suggests hepatic biotransformation of ciprofloxacin into microbiologically active metabolites. The apparent broad antibacterial spectrum of ciprofloxacin and its higher biliary levels than simultaneously determined serum concentrations suggest that this derivative is suitable for the treatment of biliary tract infections. PMID:2939796

An Universal and Easy-to-Use Model for the Pressure of Arbitrary-Shape 3D Multifunctional Integumentary Cardiac Membranes.

PubMed

Su, Yewang; Liu, Zhuangjian; Xu, Lizhi

2016-04-20

Recently developed concepts for 3D, organ-mounted electronics for cardiac applications require a universal and easy-to-use mechanical model to calculate the average pressure associated with operation of the device, which is crucial for evaluation of design efficacy and optimization. This work proposes a simple, accurate, easy-to-use, and universal model to quantify the average pressure for arbitrary-shape organs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation program for secondary spacecraft cells. Initial evaluation tests of General Electric Company standard and teflonated negative electrode 20.0 ampere-hour, nickel-cadmium spacecraft cells with auxiliary electrodes

NASA Technical Reports Server (NTRS)

1974-01-01

The standard plate cells exhibited higher average end-of-charge (EOC) voltages than the cells with teflonated negative plates; they also delivered a higher capacity output in ampere hours following these charges. All the cells reached a pressure of 20 psia before reaching the voltage limit of 1.550 volts during the pressure versus capacity test. The average ampere hours in and voltages at this pressure were 33.6 and 1.505 volts respectively for the teflonated negative plate cells and 35.5 and 1.523 volts for the standard plate cells. All cells exhibited pressure decay in the range of 1 to 7 psia during the last 30 minutes of the 1-hour open circuit stand. Average capacity out for the teflonated and standard negative plate cells was 29.4 and 29.9 ampere hours respectively.

Wavelet assessment of cerebrospinal compensatory reserve and cerebrovascular pressure reactivity

NASA Astrophysics Data System (ADS)

Latka, M.; Turalska, M.; Kolodziej, W.; Latka, D.; West, B.

2006-03-01

We employ complex continuous wavelet transforms to develop a consistent mathematical framework capable of quantifying both cerebrospinal compensatory reserve and cerebrovascular pressure--reactivity. The wavelet gain, defined as the frequency dependent ratio of time averaged wavelet coefficients of intracranial (ICP) and arterial blood pressure (ABP) fluctuations, characterizes the dampening of spontaneous arterial blood oscillations. This gain is introduced as a novel measure of cerebrospinal compensatory reserve. For a group of 10 patients who died as a result of head trauma (Glasgow Outcome Scale GOS =1) the average gain is 0.45 calculated at 0.05 Hz significantly exceeds that of 16 patients with favorable outcome (GOS=2): with gain of 0.24 with p=4x10-5. We also study the dynamics of instantaneous phase difference between the fluctuations of the ABP and ICP time series. The time-averaged synchronization index, which depends upon frequency, yields the information about the stability of the phase difference and is used as a cerebrovascular pressure--reactivity index. The average phase difference for GOS=1 is close to zero in sharp contrast to the mean value of 30^o for patients with GOS=2. We hypothesize that in patients who died the impairment of cerebral autoregulation is followed by the break down of residual pressure reactivity.

Exploring the relationship of peripheral total bilirubin, red blood cell, and hemoglobin with blood pressure during childhood and adolescence.

PubMed

Chen, Xiao-Tian; Yang, Song; Yang, Ya-Ming; Zhao, Hai-Long; Chen, Yan-Chun; Zhao, Xiang-Hai; Wen, Jin-Bo; Tian, Yuan-Rui; Yan, Wei-Li; Shen, Chong

2017-11-04

Total bilirubin is beneficial for protecting cardiovascular diseases in adults. The authors aimed to investigate the association of total bilirubin, red blood cell, and hemoglobin levels with the prevalence of high blood pressure in children and adolescents. A total of 3776 students (aged from 6 to 16 years old) were examined using cluster sampling. Pre-high blood pressure and high blood pressure were respectively defined as the point of 90th and 95th percentiles based on the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Both systolic and diastolic blood pressure were standardized into z-scores. Peripheral total bilirubin, red blood cell and hemoglobin levels were significantly correlated with age, and also varied with gender. Peripheral total bilirubin was negatively correlated with systolic blood pressure in 6- and 9-year-old boys, whilst positively correlated with diastolic blood pressure in the 12-year-old boys and 13- to 15-year-old girls (p<0.05). Higher levels of red blood cell and hemoglobin were observed in pre-high blood pressure and high blood pressure students when compared with their normotensive peers (p<0.01). The increases in red blood cell and hemoglobin were significantly associated with high blood pressure after adjusting for confounding factors. The ORs (95% CI) of each of the increases were 2.44 (1.52-3.92) and 1.04 (1.03-1.06), respectively. No statistical association between total bilirubin and high blood pressure was observed (p>0.05). Total bilirubin could be weakly correlated with both systolic and diastolic blood pressure, as correlations varied with age and gender in children and adolescents; in turn, the increased levels of red blood cell and hemoglobin are proposed to be positively associated with the prevalence of high blood pressure. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

[Obesity, high blood pressure, hypercholesterolaemia, and untreated diabetes in HIV-infected and HIV-uninfected Adults in Mbuji-Mayi (Democratic republic of congo)].

PubMed

Mukeba-Tshialala, D; Nachega, J B; Mutombo-Tshingwali, M; Arendt, V; Gilson, G; Moutschen, M

2017-12-01

Little is known about the major cardiovascular risk factors in HIV-infected as compared to the HIV-uninfected patients in the Democratic Republic of Congo (DR Congo). We determined the prevalence of hypertension, obesity (BMI ≥ 30 kg/m 2 ), total cholesterol > 200 mg/dl, HDLcholesterol &≤ 40 mg/dl, and glycemia > 126 mg/dl. We also calculated the average and/or median of total cholesterol, HDL-cholesterol, and glycemia among HIV-infected and HIV-uninfected patients.We conducted a cross-sectional study that enrolled 592 HIV-uninfected and 445 HIV-infected patients of whom 425 (95.5%) were on first-line antiretroviral therapy based on stavudine-lamivudine-nevirapine. Clinical and laboratory data of the patients were collected. The results were analyzed by chi-square, t-student, and Wilcoxon rank sum tests. 11.5% of HIV-infected patients had an average blood pressure suggesting hypertension versus 10.6% of HIV-uninfected (P = 0.751). But in absolute value, HIVinfected patients had a median of diastolic blood pressure of 90 mmHg versus 85 mmHg of HIV-uninfected (P < 0.001). 4.04% of HIV-infected patients had a BMI suggesting obesity versus 6.08% of HIV-uninfected patients (P = 0.187). For fasting glucose: 2.50% of HIV-infected patients versus 4.20% of HIV-uninfected patients had a serum fasting glucose suggesting diabetes (P<0.176). 11.9% of HIV-infected patients had a total cholesterol greater than 200 mg/dl versus 7.4% of HIVuninfected patients (P=0.019). For HDL-cholesterol: 36.40% of HIV-infected patients had a serum fasting ≤ 40 mg/dl versus 15.70% of HIV-uninfected patients (P < 0.001). HIV-infected patients had a median fasting total cholesterol higher (140 mg/ dl) thanHIV-uninfected patients (133mg/dl) [P=0.015].HIVuninfected patients had a median fasting HDL-cholesterol higher (58.5 mg/dl) than HIV-infected patients (49 mg/dl) [P < 0.001]. HIV-infected women were more likely to have a higher mean of total cholesterol: 147.70 #x00B1; 52.09 mg/dl versus 135.72 ± 48.23 mg/dl for the HIV-infected men (P = 0.014) and of HDL-cholesterol: 55.80 ± 30.77 mg/dl versus 48.24 ± 28.57mg/dl for the HIV-infected men (P = 0.008). In this study population, prevalence of hypertension was elevated in HIVinfected versus HIV-uninfected patients. Being HIV positive on first-line antiretroviral therapy based on stavudine-lamivudine-nevirapine was associated with high prevalence of total cholesterol > 200 mg/dl and HDL-cholesterol ≤ 40 mg/dl. Proactive screening and prompt management of dyslipidemia and hypertension in this population should be a priority.

Roughness topographical effects on mean momentum and stress budgets in developed turbulent channel flows

NASA Astrophysics Data System (ADS)

Aghaei Jouybari, Mostafa; Yuan, Junlin

2017-11-01

Direct numerical simulations of turbulent channel flows are carried out over two surfaces: a synthesized sand-grain surface and a realistic turbine roughness that is characterized by more prominent large-scale surface features. To separate the effects of wall-normal variation of the roughness area fraction from the (true) variation of flow statistics, the governing equations are area-averaged using intrinsic averaging, contrary to the usually practice based on the total area (i.e., superficial averaging). Additional terms appear in the mean-momentum equation resulted from the wall-normal variation of the solid fraction and play a role in the near-wall balance. Results from surfaces with a step solidity function (e.g., cubes) will also be discussed. Compared to the sand grains, the turbine surface generates stronger form-induced fluctuations, despite weaker dispersive shear stress. This is associated with more significant form-induced productions (comparable to shear production) in Reynolds stress budgets, weaker pressure work, and, consequently, more anisotropic redistribution of turbulent kinetic energy in the roughness sublayer, which potentially leads to different turbulent responses between the two surfaces in non-equilibrium flows.

Diastolic coronary artery pressure-flow velocity relationships in conscious man.

PubMed

Dole, W P; Richards, K L; Hartley, C J; Alexander, G M; Campbell, A B; Bishop, V S

1984-09-01

We characterised the diastolic pressure-flow velocity relationship in the normal left coronary artery of conscious man before and after vasodilatation with angiographic contrast medium. Phasic coronary artery pressure and flow velocity were measured in ten patients during individual diastoles (0.5 to 1.0 s) using a 20 MHz catheter-tipped, pulsed Doppler transducer. All pressure-flow velocity curves were linear over the diastolic pressure range of 110 +/- 15 (SD) mmHg to 71 +/- 7 mmHg (r = 0.97 +/- 0.01). In the basal state, values for slope and extrapolated zero flow pressure intercept averaged 0.35 +/- 0.12 cm X s-1 X mmHg-1 and 51.7 +/- 8.6 mmHg, respectively. Vasodilatation resulted in a 2.5 +/- 0.5 fold increase in mean flow velocity. The diastolic pressure-flow velocity relationship obtained during peak vasodilatation compared to that during basal conditions was characterised by a steeper slope (0.80 +/- 0.48 cm X s-1 X mmHg-1, p less than 0.001) and lower extrapolated zero flow pressure intercept (37.9 +/- 9.8 mmHg, p less than 0.05). Mean right atrial pressure for the group averaged 4.4 +/- 1.7 mmHg, while left ventricular end-diastolic pressure averaged 8.7 +/- 2.8 mmHg. These observations in man are similar to data reported in the canine coronary circulation which are consistent with a vascular waterfall model of diastolic flow regulation. In this model, coronary blood flow may be regulated by changes in diastolic zero flow pressure as well as in coronary resistance.

Nurses' attitudes towards pressure ulcer prevention in Turkey.

PubMed

Aslan, Arzu; Yavuz van Giersbergen, Meryem

2016-02-01

Pressure ulcers remain a major problem in healthcare system. Pressure ulcer incidence is widely accepted as an indicator for the quality of care. Positive attitudes towards pressure ulcer prevention have positive impacts on preventive care. The aim of this study was to identify nurses' attitude towards pressure ulcer prevention. The study design was descriptive. The study was carried out in a university hospital in Izmir, Turkey. The study population consisted of 660 nurses who work in medical and surgical clinics and intensive care units. The study sample consisted of 426 nurses who agreed to participate. Attitude towards Pressure Ulcer Prevention Instrument was used in order to evaluate nurses' attitudes. Written permissions for ethical considerations and Attitude towards Pressure Ulcer Prevention Instrument permission were obtained. Data were collected between June and July 2014. The statistics program SPSS 18 packaged software was used in the analyses of data. The average age of the nurses who took part in the study was 31.86 ± 7.09 years and the average work experience was 8.88 ± 7.41 years; 36.9% (n: 157) were working in intensive care units. The nurses' average score on the Attitude towards Pressure Ulcer Prevention Instrument was 43.74 ± 4.29 (84.12%). It was seen that the attitudes of the nurses towards the prevention of pressure ulcers was positive. To read guidelines and training time about pressure ulcer prevention affect positively attitudes towards the prevention of pressure ulcers. Copyright © 2015 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Coast Guard exposure to gasoline, MTBE, and benzene vapors during inspection of tank barges.

PubMed

Davenport, A C; Glynn, T J; Rhambarose, H

2000-01-01

A field study was conducted June through August 1996 in an attempt to quantify short-term exposure levels to Coast Guard personnel performing routine inspection activities aboard commercial tank barges carrying gasoline. Transfer and fleeting operations were monitored in the ports of Pittsburgh, Pa., Huntington, W.Va., Baton Rouge, La., and Galveston, Tex. A total of 43 personal and 68 area samples were analyzed for benzene and total hydrocarbons as gasoline ("gasoline"). Results can be summarized as follows: Personal exposure to benzene gave 15-min time-weighted-average (TWA) results ranging from <0.10 to 0.50 ppm. Area benzene levels ranged from <0.04 to 170 ppm. Personal monitoring for gasoline revealed a range of <2.0 to 590 mg/m3 with a GM of 23 mg/m3. Area sample results for gasoline ranged from 1.7 to 90,000 mg/m3. Twelve personal samples were collected for methyl-tert butyl ether (MTBE). Only two of these were above the limit of detection and had 15-min time-weighted averages of 22 ppm and 1.3 ppm. Eighteen MTBE area samples ranged in value from <3.0 to 38 ppm. Although none of the personal samples met or exceeded proposed or established short-term exposure standards, many of the area sampling results indicated that a significant risk of acute exposure exists in the vicinity of valves, pressure lines, and connections. This includes anticipated sources such as pressure vent valves as well as unexpected sources resulting from structural deficiencies onboard the vessels. These results further emphasize the value of safe work practices and proper vessel maintenance in controlling exposure to harmful chemicals.

Water relations and microclimate around the upper limit of a cloud forest in Maui, Hawai'i.

PubMed

Gotsch, Sybil G; Crausbay, Shelley D; Giambelluca, Thomas W; Weintraub, Alexis E; Longman, Ryan J; Asbjornsen, Heidi; Hotchkiss, Sara C; Dawson, Todd E

2014-07-01

The goal of this study was to determine the effects of atmospheric demand on both plant water relations and daily whole-tree water balance across the upper limit of a cloud forest at the mean base height of the trade wind inversion in the tropical trade wind belt. We measured the microclimate and water relations (sap flow, water potential, stomatal conductance, pressure-volume relations) of Metrosideros polymorpha Gaudich. var. polymorpha in three habitats bracketing the cloud forest's upper limit in Hawai'i to understand the role of water relations in determining ecotone position. The subalpine shrubland site, located 100 m above the cloud forest boundary, had the highest vapor pressure deficit, the least amount of rainfall and the highest levels of nighttime transpiration (EN) of all three sites. In the shrubland site, on average, 29% of daily whole-tree transpiration occurred at night, while on the driest day of the study 50% of total daily transpiration occurred at night. While EN occurred in the cloud forest habitat, the proportion of total daily transpiration that occurred at night was much lower (4%). The average leaf water potential (Ψleaf) was above the water potential at the turgor loss point (ΨTLP) on both sides of the ecotone due to strong stomatal regulation. While stomatal closure maintained a high Ψleaf, the minimum leaf water potential (Ψleafmin) was close to ΨTLP, indicating that drier conditions may cause drought stress in these habitats and may be an important driver of current landscape patterns in stand density. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Characterizing the relative contributions of large vessels to total ocean noise fields: a case study using the Gerry E. Studds Stellwagen Bank National Marine Sanctuary.

PubMed

Hatch, Leila; Clark, Christopher; Merrick, Richard; Van Parijs, Sofie; Ponirakis, Dimitri; Schwehr, Kurt; Thompson, Michael; Wiley, David

2008-11-01

In 2006, we used the U.S. Coast Guard's Automatic Identification System (AIS) to describe patterns of large commercial ship traffic within a U.S. National Marine Sanctuary located off the coast of Massachusetts. We found that 541 large commercial vessels transited the greater sanctuary 3413 times during the year. Cargo ships, tankers, and tug/tows constituted 78% of the vessels and 82% of the total transits. Cargo ships, tankers, and cruise ships predominantly used the designated Boston Traffic Separation Scheme, while tug/tow traffic was concentrated in the western and northern portions of the sanctuary. We combined AIS data with low-frequency acoustic data from an array of nine autonomous recording units analyzed for 2 months in 2006. Analysis of received sound levels (10-1000 Hz, root-mean-square pressure re 1 microPa +/- SE) averaged 119.5 +/- 0.3 dB at high-traffic locations. High-traffic locations experienced double the acoustic power of less trafficked locations for the majority of the time period analyzed. Average source level estimates (71-141 Hz, root-mean-square pressure re 1 microPa +/- SE) for individual vessels ranged from 158 +/- 2 dB (research vessel) to 186 +/- 2 dB (oil tanker). Tankers were estimated to contribute 2 times more acoustic power to the region than cargo ships, and more than 100 times more than research vessels. Our results indicate that noise produced by large commercial vessels was at levels and within frequencies that warrant concern among managers regarding the ability of endangered whales to maintain acoustic contact within greater sanctuary waters.

Measurement of earth pressures on concrete box culverts under highway embankments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, M.Z.; Drumm, E.C.; Bennett, R.M.

1999-07-01

To obtain a better understanding of the stresses acting on cast-in-place concrete box culverts, and to investigate the conditions which resulted in a culvert failure under about 12 meters of backfill, two sections of a new culvert were instrumented. The measured earth pressure distribution was found to depend upon the height of the embankment over the culvert. For low embankment heights (less than one-half the culvert width), the average measured vertical earth pressures, weighted by tributary length, were about 30% greater than the recommended AASHTO pressures. The measured lateral pressures were slightly greater than the AASHTO pressures. As the embankmentmore » height increased, the measured weighted average vertical stress exceeded the AASHTO pressures by about 20%. Lateral pressures which exceeded the vertical pressures were recorded at the bottom of the culvert walls, and small lateral pressures were recorded on the upper locations of the wall. The high lateral pressures at the base of the wall are consistent with the results from finite element analyses with high density (modulus) backfill material placed around the culvert.« less

Feasibility of measuring dissolved carbon dioxide based on head space partial pressures

USGS Publications Warehouse

Watten, B.J.; Boyd, C.E.; Schwartz, M.F.; Summerfelt, S.T.; Brazil, B.L.

2004-01-01

We describe an instrument prototype that measures dissolved carbon dioxide (DC) without need for standard wetted probe membranes or titration. DC is calculated using Henry's Law, water temperature, and the steady-state partial pressure of carbon dioxide that develops within the instrument's vertical gas-liquid contacting chamber. Gas-phase partial pressures were determined with either an infrared detector (ID) or by measuring voltage developed by a pH electrode immersed in an isolated sodium carbonate solution (SC) sparged with recirculated head space gas. Calculated DC concentrations were compared with those obtained by titration over a range of DC (2, 4, 8, 12, 16, 20, 24, and 28mg/l), total alkalinity (35, 120, and 250mg/l as CaCO3), total dissolved gas pressure (-178 to 120 mmHg), and dissolved oxygen concentrations (7, 14, and 18 mg/l). Statistically significant (P < 0.001) correlations were established between head space (ID) and titrimetrically determined DC concentrations (R2 = 0.987-0.999, N = 96). Millivolt and titrimetric values from the SC solution tests were also correlated (P < 0.001, R 2 = 0.997, N = 16). The absolute and relative error associated with the use of the ID and SC solution averaged 0.9mg/l DC and 7.0% and 0.6 mg/l DC and 9.6%, respectively. The precision of DC estimates established in a second test series was good; coefficients of variation (100(SD/mean)) for the head space (ID) and titration analyses were 0.99% and 1.7%. Precision of the SC solution method was 1.3%. In a third test series, a single ID was coupled with four replicate head space units so as to permit sequential monitoring (15 min intervals) of a common water source. Here, appropriate gas samples were secured using a series of solenoid valves (1.6 mm bore) activated by a time-based controller. This system configuration reduced the capital cost per sample site from US$ 2695 to 876. Absolute error averaged 2.9, 3.1, 3.7, and 2.7 mg/ l for replicates 1-4 (N = 36) during a 21-day test period (DC range, 36-40 mg/l). The ID meter was then modified so as to provide for DO as well as DC measurements across components of an intensive fish production system. ?? 2003 Elsevier B.V. All rights reserved.

Continuous monitoring of intracranial pressure for prediction of postoperative complications of hypertensive intracerebral hemorrhage.

PubMed

Yu, S-X; Zhang, Q-S; Yin, Y; Liu, Z; Wu, J-M; Yang, M-X

2016-11-01

This study evaluates the value of continuous dynamic monitoring of intracranial pressure (ICP) in patients with hypertensive intracerebral hemorrhage to predict early postoperative complications. Data from 80 patients treated in our hospital from February 2014 to February 2015 were analyzed. The patients all underwent decompressive craniectomies, and their ICP changes were monitored invasively and continuously for 1 to 7 days after surgery. The average blood loss during surgery for the group of patients was 65.3 ± 12.4 ml and the mean GCS score 8.7 ± 2.4. Cases were divided into three groups according to ICP values to compare early postoperative complications of the groups: a normal and mildly increased group (51 cases), a moderately increased group (19 cases) and a severely increased group (10 cases). To validate the analysis we first showed that comparisons among groups based on gender, age, systolic pressure, diastolic pressure, bleeding time, blood loss, operation time, craniectomy localization, and preoperative mannitol dosage yielded no statistically significant differences. In contrast, the following comparisons produced statistically significant differences: the comparison of postoperative Glasgow Coma Scale (GCS) scores showing that the lower intracranial pressure, the higher the GCS score; the postoperative rehemorrhage, cerebral edema and death ratios showing the higher the intracranial pressure, the higher the rehemorrhage ratio; the average ICP and the time to occurrence of rehemorrhage, cerebral edema or cerebral infarction, showing the relationship between the average ICP and the time to a complication. Patients with higher ICP averages suffered a complication of rehemorrhage within the first 9.6 ± 2.5 hours on average. Nevertheless, the comparison of GCS scores in those patients and the others showed no significant differences. Based on the findings, the dynamic monitoring of intracranial pressure can early and sensitively predict postoperative complications of patients with hypertensive cerebral hemorrhage, and guide the clinical intervention actively to improve the surgery outcome.

Inter-Arm Difference in Brachial Blood Pressure in the General Population of Koreans

PubMed Central

Song, Bo Mi; Shim, Jee-Seon; Lee, Myung Ha; Choi, Dong Phil

2016-01-01

Background and Objectives We investigated the inter-arm difference in blood pressure of the general Korean population to identify associated factors. Subjects and Methods A total of 806 participants aged 30 to 64 years without history of major cardiovascular disease were analyzed in this cross-sectional study. They participated in the Cardiovascular and Metabolic Disease Etiology Research Center cohort study that began in 2013. Brachial blood pressure was measured simultaneously for both arms using an automated oscillometric device equipped with two cuffs in seated position. After five minutes of rest, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured three times. The average of the three measurements was used for analysis. Multivariate logistic regression models were used to identify factors associated with inter-arm differences in blood pressure. Results The mean inter-arm difference was 3.3 mmHg for SBP and 2.0 mmHg for DBP. Large inter-arm differences (≥10 mmHg) in SBP and in DBP were found in 3.7% and 0.9% of subjects, respectively. A large inter-arm difference in SBP was associated with mean SBP (p=0.002) and C-reactive protein (p=0.014) while a large inter-arm different in DBP was only associated with body mass index (p=0.015). Sex, age, and anti-hypertensive medication use were not associated with differences in inter-arm blood pressure. Conclusion Large inter-arm difference in blood pressure is only present in a small portion of healthy Korean adults. Our findings suggest that high SBP, chronic inflammation, and obesity may be associated with larger difference in inter-arm blood pressure. PMID:27275174

Effect of Pressure on Piloted Ignition Delay of PMMA

NASA Technical Reports Server (NTRS)

McAllister, Sara; Lai, Janice; Scott, Sarah; Ramirez-Correa, Amelia; Fernandez-Pello, Carlos; Urban, David; Ruff, Gary

2008-01-01

In order to reduce the risk of decompression sickness associated with spacewalks, NASA is considering designing the next generation of exploration vehicles and habitats with a different cabin environment than used previously. The proposed environment uses a total cabin pressure of 52.7 to 58.6 kPa with an oxygen concentration of 30 to 34% by volume and was chosen with material flammability in mind. Because materials may burn differently under these conditions and there is little information on how this new environment affects the flammability of the materials onboard, it is important to conduct material flammability experiments at the intended exploration atmosphere. One method to evaluate material flammability is by its ease of ignition. To this end, piloted ignition delay tests were conducted in the Forced Ignition and Spread Test (FIST) apparatus subject to this new environment. In these tests, polymethylmethacylate (PMMA) was exposed to a range of oxidizer flow velocities and externally applied heat fluxes. The ultimate goal is to determine the individual effect of pressure and the combined effect of pressure and oxygen concentration on the ignition delay. Tests were conducted for a baseline case of normal pressure and oxygen concentration, low pressure (58.6 kPa) with normal oxygen (21%). Future work will focus on low pressure with 32% oxygen concentration (space exploration atmosphere - SEA) conditions. It was found that reducing the pressure while keeping the oxygen concentration at 21% reduced the ignition time by 17% on average. It was also noted that the critical heat flux for ignition decreases in low-pressure conditions. Because tests conducted in standard atmospheric conditions will underpredict the flammability of materials intended for use on spacecraft, fire safety onboard at exploration atmospheres may be compromised.

Learning a stick-balancing task involves task-specific coupling between posture and hand displacements.

PubMed

Cluff, Tyler; Boulet, Jason; Balasubramaniam, Ramesh

2011-08-01

Theories of motor learning argue that the acquisition of novel motor skills requires a task-specific organization of sensory and motor subsystems. We examined task-specific coupling between motor subsystems as subjects learned a novel stick-balancing task. We focused on learning-induced changes in finger movements and body sway and investigated the effect of practice on their coupling. Eight subjects practiced balancing a cylindrical wooden stick for 30 min a day during a 20 day learning period. Finger movements and center of pressure trajectories were recorded in every fifth practice session (4 in total) using a ten camera VICON motion capture system interfaced with two force platforms. Motor learning was quantified using average balancing trial lengths, which increased with practice and confirmed that subjects learned the task. Nonlinear time series and phase space reconstruction methods were subsequently used to investigate changes in the spatiotemporal properties of finger movements, body sway and their progressive coupling. Systematic increases in subsystem coupling were observed despite reduced autocorrelation and differences in the temporal properties of center of pressure and finger trajectories. The average duration of these coupled trajectories increased systematically across the learning period. In short, the abrupt transition between coupled and decoupled subsystem dynamics suggested that stick balancing is regulated by a hierarchical control mechanism that switches from collective to independent control of the finger and center of pressure. In addition to traditional measures of motor performance, dynamical analyses revealed changes in motor subsystem organization that occurred when subjects learned a novel stick-balancing task.

Effect of peroral esophageal myotomy for achalasia treatment: A Chinese study.

PubMed

Lu, Bin; Li, Meng; Hu, Yue; Xu, Yi; Zhang, Shuo; Cai, Li-Jun

2015-05-14

To assess the safety and feasibility of peroral esophageal myotomy (POEM) in patients with achalasia. From January 2012 to March 2014, 50 patients (28 men, 22 women; mean age: 42.8 years, range: 14-70 years) underwent POEM. Pre- and postoperative symptoms were quantified using the Eckardt scoring system. Barium swallow and esophagogastroscopy were performed before and after POEM, respectively. Esophageal motility was evaluated in all patients, both preoperatively and one month after POEM treatment, using a high-resolution manometry system. Manometry data, Eckardt scores, lower esophageal sphincter pressure and barium swallow results were used to evaluate the effect of the procedure. POEM was successfully completed for all patients. The mean procedure time was 55.4 ± 17.3 min and the mean total length of myotomy of the circular esophagus was 10.5 ± 2.6 cm. No specific complications occurred, with the exception of two patients that developed asymptomatic pneumomediastinum and subcutaneous emphysema. Clinical improvement in symptoms was achieved in all patients. Approximately 77.5% of patients experienced weight gain 6 mo after POEM, with an average of 4.78 kg (range: 2-15 kg). The lower esophageal sphincter resting pressure, four second integrated relaxation pressure and Eckardt scores were all significantly reduced after POEM (Ps < 0.05). A small segment of proximal esophageal peristalsis appeared postoperatively in two patients, but without normal esophageal peristalsis. The average diameter of the esophageal lumen decreased significantly from 4.39 to 3.09 cm (P < 0.01). POEM can relieve achalasia symptoms, improve gastroesophageal junction relaxation and restore esophageal body motility function, but not normal esophageal peristalsis.

Addressing reverse osmosis fouling within water reclamation--a side-by-side comparison of low-pressure membrane pretreatments.

PubMed

Kent, Fraser C; Farahbakhsh, Khosrow

2011-06-01

A tertiary membrane filtration (TMF) pilot operating on secondary effluent and a membrane bioreactor (MBR) were setup in a side-by-side study as pretreatments for two identical reverse osmosis pilot systems. The water quality of the permeate from both low-pressure membrane pretreatment systems and the fouling rate of the reverse osmosis systems were compared to assess the capabilities of the two low-pressure membrane pretreatments to prevent organic fouling of the reverse osmosis systems. Both pretreatment pilots were setup using typical operating conditions (i.e., solids retention time and mixed-liquor suspended solids). A consistent difference in water quality and reverse osmosis performance was demonstrated during the 12-month study. The MBR permeate consistently had significantly lower total organic carbon (TOC) and chemical oxygen demand concentrations, but higher color and specific UV absorbance compared with the permeate from the TMF pretreatment. The pretreatment with the MBR gave an average reverse osmosis fouling rate over the entire study (0.27 Lmh/bar.month) that was less than half of the value found for the reverse osmosis with TMF pretreatment (0.60 Lmh/bar.month). A correlation of reverse osmosis feed TOC concentration with average reverse osmosis fouling rate also was established, independent of the pretreatment method used. Results from a cleaning analysis, energy dispersive spectroscopy, and fourier transformed infrared reflectometry confirmed that the foulants were primarily organic in nature. It is concluded that, for this type of application and setup, MBR systems present an advantage over tertiary membrane polishing of secondary effluent for reverse osmosis pretreatment.

Solar radiation and water vapor pressure to forecast chickenpox epidemics.

PubMed

Hervás, D; Hervás-Masip, J; Nicolau, A; Reina, J; Hervás, J A

2015-03-01

The clear seasonality of varicella infections in temperate regions suggests the influence of meteorologic conditions. However, there are very few data on this association. The aim of this study was to determine the seasonal pattern of varicella infections on the Mediterranean island of Mallorca (Spain), and its association with meteorologic conditions and schooling. Data on the number of cases of varicella were obtained from the Network of Epidemiologic Surveillance, which is composed of primary care physicians who notify varicella cases on a compulsory basis. From 1995 to 2012, varicella cases were correlated to temperature, humidity, rainfall, water vapor pressure, atmospheric pressure, wind speed, and solar radiation using regression and time-series models. The influence of schooling was also analyzed. A total of 68,379 cases of varicella were notified during the study period. Cases occurred all year round, with a peak incidence in June. Varicella cases increased with the decrease in water vapor pressure and/or the increase of solar radiation, 3 and 4 weeks prior to reporting, respectively. An inverse association was also observed between varicella cases and school holidays. Using these variables, the best fitting autoregressive moving average with exogenous variables (ARMAX) model could predict 95 % of varicella cases. In conclusion, varicella in our region had a clear seasonality, which was mainly determined by solar radiation and water vapor pressure.

Mobile Clinic In Massachusetts Associated With Cost Savings From Lowering Blood Pressure And Emergency Department Use

PubMed Central

Hill, Caterina; Bennet, Jennifer; Vavasis, Anthony; Oriol, Nancy E.

2014-01-01

Mobile health clinics are in increasingly wide use, but evidence of their clinical impact or cost-effectiveness is limited. Using a unique data set of 5,900 patients who made a total of 10,509 visits in 2010–12 to the Family Van, an urban mobile health clinic in Massachusetts, we examined the effect of screenings and counseling provided by the clinic on blood pressure. Patients who presented with high blood pressure during their initial visit experienced average reductions of 10.7 mmHg and 6.2 mmHg in systolic and diastolic blood pressure, respectively, during their follow-up visits. These changes were associated with 32.2 percent and 44.6 percent reductions in the relative risk of myocardial infarction and stroke, respectively, which we converted into savings using estimates of the incidence and costs of these conditions over thirty months. The savings from this reduction in blood pressure and patient-reported avoided emergency department visits produced a positive lower bound for the clinic’s return on investment of 1.3. All other services of the clinic—those aimed at diabetes, obesity, and maternal health, for example—were excluded from this lower-bound estimate. Policy makers should consider mobile clinics as a delivery model for underserved communities with poor health status and high use of emergency departments. PMID:23297269

Mobile clinic in Massachusetts associated with cost savings from lowering blood pressure and emergency department use.

PubMed

Song, Zirui; Hill, Caterina; Bennet, Jennifer; Vavasis, Anthony; Oriol, Nancy E

2013-01-01

Mobile health clinics are in increasingly wide use, but evidence of their clinical impact or cost-effectiveness is limited. Using a unique data set of 5,900 patients who made a total of 10,509 visits in 2010-12 to the Family Van, an urban mobile health clinic in Massachusetts, we examined the effect of screenings and counseling provided by the clinic on blood pressure. Patients who presented with high blood pressure during their initial visit experienced average reductions of 10.7 mmHg and 6.2 mmHg in systolic and diastolic blood pressure, respectively, during their follow-up visits. These changes were associated with 32.2 percent and 44.6 percent reductions in the relative risk of myocardial infarction and stroke, respectively, which we converted into savings using estimates of the incidence and costs of these conditions over thirty months. The savings from this reduction in blood pressure and patient-reported avoided emergency department visits produced a positive lower bound for the clinic's return on investment of 1.3. All other services of the clinic-those aimed at diabetes, obesity, and maternal health, for example-were excluded from this lower-bound estimate. Policy makers should consider mobile clinics as a delivery model for underserved communities with poor health status and high use of emergency departments.

Reduction of dissipation in a thermal engine by means of periodic changes of external constraintsa)

NASA Astrophysics Data System (ADS)

Escher, Claus; Ross, John

1985-03-01

We consider a thermal engine driven by chemical reactions, which take place in a continuous flow, stirred tank reactor fitted with a movable piston. Work can be produced by means of a heat engine coupled to the products and to an external heat bath, and by the piston. Two modes of operation are compared, each with fixed input rate of chemicals: one with periodic variation of an external constraint [mode (b)], in which we vary the external pressure, and one without such variation [mode (a)]. We derive equations for the total power output in each of the two modes. The power output in mode (b) can be larger than that of mode (a) for the same chemical throughput and for the same average value of the external pressure. For a particularly simple case it is shown that the total power output in mode (b) is larger than that in (a) if work is done by the piston. At the same time the entropy production is decreased and the efficiency is increased. The possibility of an increased power output is due to the proper control of the relative phase of the externally varied constraint and its conjugate variable, the external pressure and the volume. This control is achieved by the coupling of nonlinear kinetics to the externally varied constraint. Details of specific mechanisms and the occurrence of resonance phenomena are presented in the following article.

Relation of raw and cooked vegetable consumption to blood pressure: the INTERMAP Study.

PubMed

Chan, Q; Stamler, J; Brown, I J; Daviglus, M L; Van Horn, L; Dyer, A R; Oude Griep, L M; Miura, K; Ueshima, H; Zhao, L; Nicholson, J K; Holmes, E; Elliott, P

2014-06-01

Inverse associations have been reported of overall vegetable intake to blood pressure (BP); whether such relations prevail for both raw and cooked vegetables has not been examined. Here we report cross-sectional associations of vegetable intakes with BP for 2195 Americans ages 40-59 in the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) using four standardized multi-pass 24-h dietary recalls and eight BP measurements. Relations to BP of raw and cooked vegetables consumption, and main individual constituents were assessed by multiple linear regression. Intakes of both total raw and total cooked vegetables considered separately were inversely related to BP in multivariate-adjusted models. Estimated average systolic BP differences associated with two s.d. differences in raw vegetable intake (68 g per 1000 kcal) and cooked vegetable intake (92 g per 1000 kcal) were -1.9 mm Hg (95% confidence interval (CI): -3.1, -0.8; P=0.001) and -1.3 mm Hg (95% CI: -2.5, -0.2; P=0.03) without body mass index (BMI) in the full model; -1.3 mm Hg (95% CI: -2.4, -0.2; P=0.02) and -0.9 mm Hg (95% CI: -2.0, 0.2; P=0.1) with additional adjustment for BMI. Among commonly consumed individual raw vegetables, tomatoes, carrots, and scallions related significantly inversely to BP. Among commonly eaten cooked vegetables, tomatoes, peas, celery, and scallions related significantly inversely to BP.

Three Dimensional Compressible Turbulent Flow Computations for a Diffusing S-Duct With/Without Vortex Generators

NASA Technical Reports Server (NTRS)

Cho, Soo-Yong; Greber, Isaac

1994-01-01

Numerical investigations on a diffusing S-duct with/without vortex generators and a straight duct with vortex generators are presented. The investigation consists of solving the full three-dimensional unsteady compressible mass averaged Navier-Stokes equations. An implicit finite volume lower-upper time marching code (RPLUS3D) has been employed and modified. A three-dimensional Baldwin-Lomax turbulence model has been modified in conjunction with the flow physics. A model for the analysis of vortex generators in a fully viscous subsonic internal flow is evaluated. A vortical structure for modeling the shed vortex is used as a source term in the computation domain. The injected vortex paths in the straight duct are compared with the analysis by two kinds of prediction models. The flow structure by the vortex generators are investigated along the duct. Computed results of the flow in a circular diffusing S-duct provide an understanding of the flow structure within a typical engine inlet system. These are compared with the experimental wall static-pressure, static- and total-pressure field, and secondary velocity profiles. Additionally, boundary layer thickness, skin friction values, and velocity profiles in wall coordinates are presented. In order to investigate the effect of vortex generators, various vortex strengths are examined in this study. The total-pressure recovery and distortion coefficients are obtained at the exit of the S-duct. The numerical results clearly depict the interaction between the low velocity flow by the flow separation and the injected vortices.

Stem geometry changes initial femoral fixation stability of a revised press-fit hip prosthesis: A finite element study.

PubMed

Russell, Robert D; Huo, Michael H; Rodrigues, Danieli C; Kosmopoulos, Victor

2016-11-14

Stable femoral fixation during uncemented total hip arthroplasty is critical to allow for subsequent osseointegration of the prosthesis. Varying stem designs provide surgeons with multiple options to gain femoral fixation. The purpose of this study was to compare the initial fixation stability of cylindrical and tapered stem implants using two different underreaming techniques (press-fit conditions) for revision total hip arthroplasty (THA). A finite element femur model was created from three-dimensional computed tomography images simulating a trabecular bone defect commonly observed in revision THA. Two 18-mm generic femoral hip implants were modeled using the same geometry, differing only in that one had a cylindrical stem and the other had a 2 degree tapered stem. Surgery was simulated using a 0.05-mm and 0.01-mm press-fit and tested with a physiologically relevant loading protocol. Mean contact pressure was influenced more by the surgical technique than by the stem geometry. The 0.05-mm press-fit condition resulted in the highest contact pressures for both the cylindrical (27.35 MPa) and tapered (20.99 MPa) stems. Changing the press-fit to 0.01-mm greatly decreased the contact pressure by 79.8% and 78.5% for the cylindrical (5.53 MPa) and tapered (4.52 MPa) models, respectively. The cylindrical stem geometry consistently showed less relative micromotion at all the cross-sections sampled as compared to the tapered stem regardless of press-fit condition. This finite element analysis study demonstrates that tapered stem results in lower average contact pressure and greater micromotion at the implant-bone interface than a cylindrical stem geometry. More studies are needed to establish how these different stem geometries perform in such non-ideal conditions encountered in revision THA cases where less bone stock is available.

Optimum Tilt Angle of Flow Guide in Steam Turbine Exhaust Hood Considering the Effect of Last Stage Flow Field

NASA Astrophysics Data System (ADS)

CAO, Lihua; LIN, Aqiang; LI, Yong; XIAO, Bin

2017-07-01

Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam turbine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional (3D) Reynolds time-averaged N-S equations and standard k- ɛ turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30° to 40°, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effective enthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.

Walking performance in people with diabetic neuropathy: benefits and threats.

PubMed

Kanade, R V; van Deursen, R W M; Harding, K; Price, P

2006-08-01

Walking is recommended as an adjunct therapy to diet and medication in diabetic patients, with the aim of improving physical fitness, glycaemic control and body weight reduction. Therefore we evaluated walking activity on the basis of capacity, performance and potential risk of plantar injury in the diabetic population before it can be prescribed safely. Twenty-three subjects with diabetic neuropathy (DMPN) were compared with 23 patients with current diabetic foot ulcers, 16 patients with partial foot amputations and 22 patients with trans-tibial amputations. The capacity for walking was measured using a total heart beat index (THBI). Gait velocity and average daily strides were measured to assess the performance of walking, and its impact on weight-bearing was studied using maximum peak pressure. THBI increased (p<0.01) and gait velocity and daily stride count fell (p<0.001 for both) with progression of foot complications. The maximum peak pressures over the affected foot of patients with diabetic foot ulcers (p<0.05) and partial foot amputations (p<0.01) were higher than in the group with DMPN. On the contralateral side, the diabetic foot ulcer group showed higher maximum peak pressure over the total foot (p<0.05), and patients with partial foot amputations (p<0.01) and trans-tibial amputations (p<0.05) showed higher maximum peak pressure over the heel. Walking capacity and performance decrease with progression of foot complications. Although walking is recommended to improve fitness, it cannot be prescribed in isolation, considering the increased risk of plantar injury. For essential walking we therefore recommend the use of protective footwear. Walking exercise should be supplemented by partial or non-weight-bearing exercises to improve physical fitness in diabetic populations.

Stage-frit: A straightforward sub-2 μm nano-liquid chromatography column fabrication for proteomic analysis.

PubMed

Hsieh, Ming-Yueh; Hsiao, He-Hsuan

2015-07-30

In this work we demonstrated a facile method for the fabrication of C18 coordination polymer gel in a capillary, called stage-frit, which was efficiently applied to pack sub-2 μm C18 beads into the capillary by a high pressure bomb for the online separation of proteolytic peptides. The back pressure of the column with 10 cm × 75 μm i.d. is regularly lower than 170 bar at a flow rate of 300 nl/min, which could be operated on a common nanoLC system instead of nanoUPLC system due to the good permeability, low back pressure and high mechanical stress of the frit that will totally reduce the cost for the purchase of instrument. The stage-frit allows long-term continuous flow of the solvent and no significant beads loss or pressure instability was observed during the period. The repeatability of retention time for fifteen BSA tryptic peaks was found to be less than 1.08% (RSD) in six time nanoLC-ESI-MS/MS experiments. The average full width at half maximum (FWHM) of peptide peaks is 5.87 s. The sub-2 μm stage-frit nanoLC column showed better sensitivity than the commercial available for large scale proteomic analysis of total tissue proteins from human spleen. The number of identified peptides is approximately 0.4-fold and 0.2-fold higher than that obtained by utilizing commercial columns packed with 3 μm and 1.8 μm C18 materials, respectively. In the field of analytical chemistry, particularly the use of nanoLC systems, stage-frit nanoLC column offers a great potential for the separation of complex mixtures. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhancing cuttings removal with gas blasts while drilling on Mars

NASA Astrophysics Data System (ADS)

Zacny, K. A.; Quayle, M. C.; Cooper, G. A.

2005-04-01

Future missions to Mars envision use of drills for subsurface exploration. Since the Martian atmosphere precludes the use of liquids for cuttings removal, proposed drilling machines utilize mechanical cuttings removal systems such as augers. However, an auger can substantially contribute to the total power requirements, and in the worst scenario it can choke. A number of experiments conducted under Martian pressures showed that intermittent blasts of gas at low differential pressures can effectively lift the cuttings out of the hole. A gas flushing system could be incorporated into the drill assembly for assistance in clearing the holes of rock cuttings or for redundancy in case of auger jamming. A number of variables such as the particle size distribution of the rock powder, the type of gas used, the bit and auger side clearances, the initial mass of cuttings, and the ambient pressure were investigated and found to affect the efficiency. In all tests the initial volume of gas was close to 1 L and the differential pressure was varied to achieve desired clearing efficiencies. Particles were being lifted out of the hole at a maximum speed of 6 m/s at a differential pressure of 25 torr and ambient pressure of 5 torr. Flushing tests lasted on average for 2 s. The power required to compress the thin Martian atmosphere to achieve a sufficient gas blast every minute or so at 10% efficiency was calculated to be of the order of a few watts.

An Inverse Square Law Variation for Hubble's Constant

NASA Astrophysics Data System (ADS)

Day, Orville W., Jr.

1999-11-01

The solution to Einstein's gravitational field equations is examined, using a Robertson-Walker metric with positive curvature, when Hubble's parameter, H_0, is taken to be a constant divided by R^2. R is the cosmic scale factor for the universe treated as a three-dimensional hypersphere in a four-dimensional Euclidean space. This solution produces a self-energy of the universe, W^(0)_self, proportional to the square of the total mass, times the universal gravitational constant divided by the cosmic scale factor, R. This result is totally analogous to the self-energy of the electromagnetic field of a charged particle, W^(0)_self = ke^2/2r, where the total charge e is squared, k is the universal electric constant and r is the scale factor, usually identified as the radius of the particle. It is shown that this choice for H0 leads to physically meaningful results for the average mass density and pressure, and a deacceleration parameter q_0=1.

Cowpeas and pinto beans: yields and light efficiency of candidate space crops in the Laboratory Biosphere closed ecological system

NASA Astrophysics Data System (ADS)

Nelson, M.; Dempster, W. F.; Silverstone, S.; Alling, A.; Allen, J. P.; van Thillo, M.

An experiment utilizing cowpeas Vigna unguiculata pinto beans Phaseolus vulgaris L and Apogee ultra-dwarf wheat was conducted in the soil-based closed ecological facility Laboratory Biosphere from February to May 2005 The lighting regime was 13 hours light 11 hours dark at a light intensity of 960 mu mol m -2 s -1 45 moles m -2 day -1 supplied by high-pressure sodium lamps The pinto beans and cowpeas were grown at two different plant densities The pinto bean produced 710 g m -2 total aboveground biomass and 341 g m -2 at 33 5 plants per m 2 and at 37 5 plants per m 2 produced 1092 g m -2 total biomass and 537 g m -2 of dry seed an increase of almost 50 Cowpeas at 28 plants m -2 yielded 1060 g m -2 of total biomass and 387 g seed m -2 outproducing the less dense planting by more than double 209 in biomass and 86 more seed as the planting of 21 plants m -2 produced 508 g m-2 of total biomass and 209 g m-2 of seed Edible yield rate EYR for the denser cowpea bean was 4 6 g m -2 day -1 vs 2 5 g m -2 day -1 for the less dense stand average yield was 3 5 g m -2 day -1 EYR for the denser pinto bean was 8 5 g m -2 day -1 vs 5 3 g m -2 day -1 average EYR for the pinto beans was 7 0 g m -2 day -1 Yield efficiency rate YER the ratio of edible to non-edible biomass was 0 97 for the dense pinto bean 0 92 for the less dense pinto bean and average 0 94 for the entire crop The cowpeas

Puffing Topography and Nicotine Intake of Electronic Cigarette Users

PubMed Central

Behar, Rachel Z.; Hua, My; Talbot, Prue

2015-01-01

Background Prior electronic cigarette (EC) topography data are based on two video analyses with limited parameters. Alternate methods for measuring topography are needed to understand EC use and nicotine intake. Objectives This study evaluated EC topography with a CReSS Pocket device and quantified nicotine intake. Methods Validation tests on pressure drop, flow rate, and volume confirmed reliable performance of the CReSS Pocket device. Twenty participants used Blu Cigs and V2 Cigs for 10 minute intervals with a 10–15 minute break between brands. Brand order was reversed and repeated within 7 days Data were analyzed to determine puff duration, puff count, volume, flow rate, peak flow, and inter-puff interval. Nicotine intake was estimated from cartomizer fluid consumption and topography data. Results Nine patterns of EC use were identified. The average puff count and inter-puff interval were 32 puffs and 17.9 seconds. All participants, except one, took more than 20 puffs/10 minutes. The averages for puff duration (2.65 seconds/puff), volume/puff (51ml/puff), total puff volume (1,579 ml), EC fluid consumption (79.6 mg), flow rate (20 ml/s), and peak flow rate (27 ml/s) were determined for 10-minute sessions. All parameters except total puff count were significantly different for Blu versus V2 EC. Total volume for Blu versus V2 was four-times higher than for conventional cigarettes. Average nicotine intake for Blu and V2 across both sessions was 1.2 ± 0.5 mg and 1.4 ± 0.7 mg, respectively, which is similar to conventional smokers. Conclusions EC puffing topography was variable among participants in the study, but often similar within an individual between brands or days. Puff duration, inter-puff interval, and puff volume varied from conventional cigarette standards. Data on total puff volume and nicotine intake are consistent with compensatory usage of EC. These data can contribute to the development of a standard protocol for laboratory testing of EC products. PMID:25664463

Computational Model for Tumor Oxygenation Applied to Clinical Data on Breast Tumor Hemoglobin Concentrations Suggests Vascular Dilatation and Compression.

PubMed

Welter, Michael; Fredrich, Thierry; Rinneberg, Herbert; Rieger, Heiko

2016-01-01

We present a computational model for trans-vascular oxygen transport in synthetic tumor and host tissue blood vessel networks, aiming at qualitatively explaining published data of optical mammography, which were obtained from 87 breast cancer patients. The data generally show average hemoglobin concentration to be higher in tumors versus host tissue whereas average oxy-to total hemoglobin concentration (vascular segment RBC-volume-weighted blood oxygenation) can be above or below normal. Starting from a synthetic arterio-venous initial network the tumor vasculature was generated by processes involving cooption, angiogenesis, and vessel regression. Calculations of spatially resolved blood flow, hematocrit, oxy- and total hemoglobin concentrations, blood and tissue oxygenation were carried out for ninety tumor and associated normal vessel networks starting from various assumed geometries of feeding arteries and draining veins. Spatial heterogeneity in the extra-vascular partial oxygen pressure distribution can be related to various tumor compartments characterized by varying capillary densities and blood flow characteristics. The reported higher average hemoglobin concentration of tumors is explained by growth and dilatation of tumor blood vessels. Even assuming sixfold metabolic rate of oxygen consumption in tumorous versus host tissue, the predicted oxygen hemoglobin concentrations are above normal. Such tumors are likely associated with high tumor blood flow caused by high-caliber blood vessels crossing the tumor volume and hence oxygen supply exceeding oxygen demand. Tumor oxy- to total hemoglobin concentration below normal could only be achieved by reducing tumor vessel radii during growth by a randomly selected factor, simulating compression caused by intra-tumoral solid stress due to proliferation of cells and extracellular matrix. Since compression of blood vessels will impede chemotherapy we conclude that tumors with oxy- to total hemoglobin concentration below normal are less likely to respond to chemotherapy. Such behavior was recently reported for neo-adjuvant chemotherapy of locally advanced breast tumors.

Computational Model for Tumor Oxygenation Applied to Clinical Data on Breast Tumor Hemoglobin Concentrations Suggests Vascular Dilatation and Compression

PubMed Central

Welter, Michael; Fredrich, Thierry; Rinneberg, Herbert; Rieger, Heiko

2016-01-01

We present a computational model for trans-vascular oxygen transport in synthetic tumor and host tissue blood vessel networks, aiming at qualitatively explaining published data of optical mammography, which were obtained from 87 breast cancer patients. The data generally show average hemoglobin concentration to be higher in tumors versus host tissue whereas average oxy-to total hemoglobin concentration (vascular segment RBC-volume-weighted blood oxygenation) can be above or below normal. Starting from a synthetic arterio-venous initial network the tumor vasculature was generated by processes involving cooption, angiogenesis, and vessel regression. Calculations of spatially resolved blood flow, hematocrit, oxy- and total hemoglobin concentrations, blood and tissue oxygenation were carried out for ninety tumor and associated normal vessel networks starting from various assumed geometries of feeding arteries and draining veins. Spatial heterogeneity in the extra-vascular partial oxygen pressure distribution can be related to various tumor compartments characterized by varying capillary densities and blood flow characteristics. The reported higher average hemoglobin concentration of tumors is explained by growth and dilatation of tumor blood vessels. Even assuming sixfold metabolic rate of oxygen consumption in tumorous versus host tissue, the predicted oxygen hemoglobin concentrations are above normal. Such tumors are likely associated with high tumor blood flow caused by high-caliber blood vessels crossing the tumor volume and hence oxygen supply exceeding oxygen demand. Tumor oxy- to total hemoglobin concentration below normal could only be achieved by reducing tumor vessel radii during growth by a randomly selected factor, simulating compression caused by intra-tumoral solid stress due to proliferation of cells and extracellular matrix. Since compression of blood vessels will impede chemotherapy we conclude that tumors with oxy- to total hemoglobin concentration below normal are less likely to respond to chemotherapy. Such behavior was recently reported for neo-adjuvant chemotherapy of locally advanced breast tumors. PMID:27547939

Vascular capacitance and cardiac output in pacing-induced canine models of acute and chronic heart failure.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1995-11-01

The relationship between stressed and total blood volume, total vascular capacitance, central blood volume, cardiac output (CO), and pulmonary capillary wedge pressure (Ppcw) was investigated in pacing-induced acute and chronic heart failure. Acute heart failure was induced in anesthetized splenectomized dogs by a volume load (20 mL/kg over 10 min) during rapid right ventricular pacing at 250 beats/min (RRVP) for 60 min. Chronic heart failure was induced by continuous RRVP for 2-6 weeks (average 24 +/- 2 days). Total vascular compliance and capacitance were calculated from the mean circulatory filling pressure (Pmcf) during transient circulatory arrest after acetylcholine at three different circulating volumes. Stressed blood volume was calculated as a product of compliance and Pmcf, with the total blood volume measured by a dye dilution. Central blood volume (CBV) and CO were measured by thermodilution. Central (heart and lung) vascular capacitance was estimated from the plot of Ppcw against CBV. Acute volume loading without RRVP increased capacitance and CO, whereas after volume loading with RRVP, capacitance and CO were unaltered from baseline. Chronic RRVP reduced capacitance and CO. All interventions, volume +/- RRVP or chronic RRVP, increased stressed and central blood volumes and Ppcw. Acute or chronic RRVP reduced central vascular capacitance. Cardiac output was increased when stressed and unstressed blood volumes increased proportionately as during volume loading alone. When CO was reduced and Ppcw increased, as during chronic RRVP or acute RRVP plus a volume load, stressed blood volume was increased and unstressed blood volume was decreased. Thus, interventions that reduced CO and increased Ppcw also increased stressed and reduced unstressed blood volume and total vascular capacitance.

High cost of stage IV pressure ulcers.

PubMed

Brem, Harold; Maggi, Jason; Nierman, David; Rolnitzky, Linda; Bell, David; Rennert, Robert; Golinko, Michael; Yan, Alan; Lyder, Courtney; Vladeck, Bruce

2010-10-01

The aim of this study was to calculate and analyze the cost of treatment for stage IV pressure ulcers. A retrospective chart analysis of patients with stage IV pressure ulcers was conducted. Hospital records and treatment outcomes of these patients were followed up for a maximum of 29 months and analyzed. Costs directly related to the treatment of pressure ulcers and their associated complications were calculated. Nineteen patients with stage IV pressure ulcers (11 hospital-acquired and 8 community-acquired) were identified and their charts were reviewed. The average hospital treatment cost associated with stage IV pressure ulcers and related complications was $129,248 for hospital-acquired ulcers during 1 admission, and $124,327 for community-acquired ulcers over an average of 4 admissions. The costs incurred from stage IV pressure ulcers are much greater than previously estimated. Halting the progression of early stage pressure ulcers has the potential to eradicate enormous pain and suffering, save thousands of lives, and reduce health care expenditures by millions of dollars. Copyright © 2010 Elsevier Inc. All rights reserved.

Changes in Contact Area in Meniscus Horizontal Cleavage Tears Subjected to Repair and Resection.

PubMed

Beamer, Brandon S; Walley, Kempland C; Okajima, Stephen; Manoukian, Ohan S; Perez-Viloria, Miguel; DeAngelis, Joseph P; Ramappa, Arun J; Nazarian, Ara

2017-03-01

To assess the changes in tibiofemoral contact pressure and contact area in human knees with a horizontal cleavage tear before and after treatment. Ten human cadaveric knees were tested. Pressure sensors were placed under the medial meniscus and the knees were loaded at twice the body weight for 20 cycles at 0°, 10°, and 20° of flexion. Contact area and pressure were recorded for the intact meniscus, the meniscus with a horizontal cleavage tear, after meniscal repair, after partial meniscectomy (single leaflet), and after subtotal meniscectomy (double leaflet). The presence of a horizontal cleavage tear significantly increased average peak contact pressure and reduced effective average tibiofemoral contact area at all flexion angles tested compared with the intact state (P < .03). There was approximately a 70% increase in contact pressure after creation of the horizontal cleavage tear. Repairing the horizontal cleavage tear restored peak contact pressures and areas to within 15% of baseline, statistically similar to the intact state at all angles tested (P < .05). Partial meniscectomy and subtotal meniscectomy significantly increased average peak contact pressure and reduced average contact area at all degrees of flexion compared with the intact state (P < .05). The presence of a horizontal cleavage tear in the medial meniscus causes a significant reduction in contact area and a significant elevation in contact pressure. These changes may accelerate joint degeneration. A suture-based repair of these horizontal cleavage tears returns the contact area and contact pressure to nearly normal, whereas both partial and subtotal meniscectomy lead to significant reductions in contact area and significant elevations in contact pressure within the knee. Repairing horizontal cleavage tears may lead to improved clinical outcomes by preserving meniscal tissue and the meniscal function. Understanding contact area and peak contact pressure resulting from differing strategies for treating horizontal cleavage tears will allow the surgeon to evaluate the best strategy for treating his or her patients who present with this meniscal pathology. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Characteristics of ion flow in the quiet state of the inner plasma sheet

NASA Technical Reports Server (NTRS)

Angelopoulos, V.; Kennel, C. F.; Coroniti, F. V.; Pellat, R.; Spence, H. E.; Kivelson, M. G.; Walker, R. J.; Baumjohann, W.; Feldman, W. C.; Gosling, J. T.

1993-01-01

We use AMPTE/IRM and ISEE 2 data to study the properties of the high beta plasma sheet, the inner plasma sheet (IPS). Bursty bulk flows (BBFs) are excised from the two databases, and the average flow pattern in the non-BBF (quiet) IPS is constructed. At local midnight this ensemble-average flow is predominantly duskward; closer to the flanks it is mostly earthward. The flow pattern agrees qualitatively with calculations based on the Tsyganenko (1987) model (T87), where the earthward flow is due to the ensemble-average cross tail electric field and the duskward flow is the diamagnetic drift due to an inward pressure gradient. The IPS is on the average in pressure equilibrium with the lobes. Because of its large variance the average flow does not represent the instantaneous flow field. Case studies also show that the non-BBF flow is highly irregular and inherently unsteady, a reason why earthward convection can avoid a pressure balance inconsistency with the lobes. The ensemble distribution of velocities is a fundamental observable of the quiet plasma sheet flow field.

Effect of compression ratio, nozzle opening pressure, engine load, and butanol addition on nanoparticle emissions from a non-road diesel engine.

PubMed

Maurya, Rakesh Kumar; Saxena, Mohit Raj; Rai, Piyush; Bhardwaj, Aashish

2018-05-01

Currently, diesel engines are more preferred over gasoline engines due to their higher torque output and fuel economy. However, diesel engines confront major challenge of meeting the future stringent emission norms (especially soot particle emissions) while maintaining the same fuel economy. In this study, nanosize range soot particle emission characteristics of a stationary (non-road) diesel engine have been experimentally investigated. Experiments are conducted at a constant speed of 1500 rpm for three compression ratios and nozzle opening pressures at different engine loads. In-cylinder pressure history for 2000 consecutive engine cycles is recorded and averaged data is used for analysis of combustion characteristics. An electrical mobility-based fast particle sizer is used for analyzing particle size and mass distributions of engine exhaust particles at different test conditions. Soot particle distribution from 5 to 1000 nm was recorded. Results show that total particle concentration decreases with an increase in engine operating loads. Moreover, the addition of butanol in the diesel fuel leads to the reduction in soot particle concentration. Regression analysis was also conducted to derive a correlation between combustion parameters and particle number emissions for different compression ratios. Regression analysis shows a strong correlation between cylinder pressure-based combustion parameters and particle number emission.

Direct Left Atrial Pressure Monitoring in Severe Heart Failure: Long-Term Sensor Performance

PubMed Central

Ritzema, Jay; Eigler, Neal L.; Melton, Iain C.; Krum, Henry; Adamson, Philip B.; Kar, Saibal; Shah, Prediman K.; Whiting, James S.; Heywood, J. Thomas; Rosero, Spencer; Singh, Jagmeet P.; Saxon, Leslie; Matthews, Ray; Crozier, Ian G.; Abraham, William T.

2010-01-01

We report the stability, accuracy, and development history of a new left atrial pressure (LAP) sensing system in ambulatory heart failure (HF) patients. A total of 84 patients with advanced HF underwent percutaneous transseptal implantation of the pressure sensor. Quarterly noninvasive calibration by modified Valsalva maneuver was achieved in all patients, and 96.5% of calibration sessions were successful with a reproducibility of 1.2 mmHg. Absolute sensor drift was maximal after 3 months at 4.7 mmHg (95% CI, 3.2–6.2 mmHg) and remained stable through 48 months. LAP was highly correlated with simultaneous pulmonary wedge pressure at 3 and 12 months (r = 0.98, average difference of 0.8 ± 4.0 mmHg). Freedom from device failure was 95% (n = 37) at 2 years and 88% (n = 12) at 4 years. Causes of failure were identified and mitigated with 100% freedom from device failure and less severe anomalies in the last 41 consecutive patients (p = 0.005). Accurate and reliable LAP measurement using a chronic implanted monitoring system is safe and feasible in patients with advanced heart failure. PMID:20945124

Comparison of experimental with theoretical total-pressure loss in parallel-walled turbojet combustors

NASA Technical Reports Server (NTRS)

Dittrich, Ralph T

1957-01-01

An experimental investigation of combustor total-pressure loss was undertaken to confirm previous theoretical analyses of effects of geometric and flow variables and of heat addition. The results indicate that a reasonable estimate of cold-flow total-pressure-loss coefficient may be obtained from the theoretical analyses. Calculated total-pressure loss due to heat addition agreed with experimental data only when there was no flame ejection from the liner at the upstream air-entry holes.

Silver nanocube aggregation gradient materials in search for total internal reflection with high phase sensitivity

NASA Astrophysics Data System (ADS)

König, Tobias A. F.; Ledin, Petr A.; Russell, Michael; Geldmeier, Jeffrey A.; Mahmoud, Mahmoud. A.; El-Sayed, Mostafa A.; Tsukruk, Vladimir V.

2015-03-01

We fabricated monolayer coatings of a silver nanocube aggregation to create a step-wise optical strip by applying different surface pressures during slow Langmuir-Blodgett deposition. The varying amount of randomly distributed nanocube aggregates with different surface coverages in gradient manner due to changes in surface pressure allows for continuous control of the polarization sensitive absorption of the incoming light over a broad optical spectrum. Optical characterization under total internal reflection conditions combined with electromagnetic simulations reveal that the broadband light absorption depends on the relative orientation of the nanoparticles to the polarization of the incoming light. By using computer simulations, we found that the electric field vector of the s-polarized light interacts with the different types of silver nanocube aggregations to excite different plasmonic resonances. The s-polarization shows dramatic changes of the plasmonic resonances at different angles of incidence (shift of 64 nm per 10° angle of incidence). With a low surface nanocube coverage (from 5% to 20%), we observed a polarization-selective high absorption of 80% (with an average 75%) of the incoming light over a broad optical range in the visible region from 400 nm to 700 nm. This large-area gradient material with location-dependent optical properties can be of particular interest for broadband light absorption, phase-sensitive sensors, and imaging.We fabricated monolayer coatings of a silver nanocube aggregation to create a step-wise optical strip by applying different surface pressures during slow Langmuir-Blodgett deposition. The varying amount of randomly distributed nanocube aggregates with different surface coverages in gradient manner due to changes in surface pressure allows for continuous control of the polarization sensitive absorption of the incoming light over a broad optical spectrum. Optical characterization under total internal reflection conditions combined with electromagnetic simulations reveal that the broadband light absorption depends on the relative orientation of the nanoparticles to the polarization of the incoming light. By using computer simulations, we found that the electric field vector of the s-polarized light interacts with the different types of silver nanocube aggregations to excite different plasmonic resonances. The s-polarization shows dramatic changes of the plasmonic resonances at different angles of incidence (shift of 64 nm per 10° angle of incidence). With a low surface nanocube coverage (from 5% to 20%), we observed a polarization-selective high absorption of 80% (with an average 75%) of the incoming light over a broad optical range in the visible region from 400 nm to 700 nm. This large-area gradient material with location-dependent optical properties can be of particular interest for broadband light absorption, phase-sensitive sensors, and imaging. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06430e

Estimation of lower flammability limits of C-H compounds in air at atmospheric pressure, evaluation of temperature dependence and diluent effect.

PubMed

Mendiburu, Andrés Z; de Carvalho, João A; Coronado, Christian R

2015-03-21

Estimation of the lower flammability limits of C-H compounds at 25 °C and 1 atm; at moderate temperatures and in presence of diluent was the objective of this study. A set of 120 C-H compounds was divided into a correlation set and a prediction set of 60 compounds each. The absolute average relative error for the total set was 7.89%; for the correlation set, it was 6.09%; and for the prediction set it was 9.68%. However, it was shown that by considering different sources of experimental data the values were reduced to 6.5% for the prediction set and to 6.29% for the total set. The method showed consistency with Le Chatelier's law for binary mixtures of C-H compounds. When tested for a temperature range from 5 °C to 100 °C, the absolute average relative errors were 2.41% for methane; 4.78% for propane; 0.29% for iso-butane and 3.86% for propylene. When nitrogen was added, the absolute average relative errors were 2.48% for methane; 5.13% for propane; 0.11% for iso-butane and 0.15% for propylene. When carbon dioxide was added, the absolute relative errors were 1.80% for methane; 5.38% for propane; 0.86% for iso-butane and 1.06% for propylene. Copyright © 2014 Elsevier B.V. All rights reserved.

Modelling gas dynamics in 1D ducts with abrupt area change

NASA Astrophysics Data System (ADS)

Menina, R.; Saurel, R.; Zereg, M.; Houas, L.

2011-09-01

Most gas dynamic computations in industrial ducts are done in one dimension with cross-section-averaged Euler equations. This poses a fundamental difficulty as soon as geometrical discontinuities are present. The momentum equation contains a non-conservative term involving a surface pressure integral, responsible for momentum loss. Definition of this integral is very difficult from a mathematical standpoint as the flow may contain other discontinuities (shocks, contact discontinuities). From a physical standpoint, geometrical discontinuities induce multidimensional vortices that modify the surface pressure integral. In the present paper, an improved 1D flow model is proposed. An extra energy (or entropy) equation is added to the Euler equations expressing the energy and turbulent pressure stored in the vortices generated by the abrupt area variation. The turbulent energy created by the flow-area change interaction is determined by a specific estimate of the surface pressure integral. Model's predictions are compared with 2D-averaged results from numerical solution of the Euler equations. Comparison with shock tube experiments is also presented. The new 1D-averaged model improves the conventional cross-section-averaged Euler equations and is able to reproduce the main flow features.

Big and small: menisci in soil pores affect water pressures, dynamics of groundwater levels, and catchment-scale average matric potentials

NASA Astrophysics Data System (ADS)

de Rooij, G. H.

2010-09-01

Soil water is confined behind the menisci of its water-air interface. Catchment-scale fluxes (groundwater recharge, evaporation, transpiration, precipitation, etc.) affect the matric potential, and thereby the interface curvature and the configuration of the phases. In turn, these affect the fluxes (except precipitation), creating feedbacks between pore-scale and catchment-scale processes. Tracking pore-scale processes beyond the Darcy scale is not feasible. Instead, for a simplified system based on the classical Darcy's Law and Laplace-Young Law we i) clarify how menisci transfer pressure from the atmosphere to the soil water, ii) examine large-scale phenomena arising from pore-scale processes, and iii) analyze the relationship between average meniscus curvature and average matric potential. In stagnant water, changing the gravitational potential or the curvature of the air-water interface changes the pressure throughout the water. Adding small amounts of water can thus profoundly affect water pressures in a much larger volume. The pressure-regulating effect of the interface curvature showcases the meniscus as a pressure port that transfers the atmospheric pressure to the water with an offset directly proportional to its curvature. This property causes an extremely rapid rise of phreatic levels in soils once the capillary fringe extends to the soil surface and the menisci flatten. For large bodies of subsurface water, the curvature and vertical position of any meniscus quantify the uniform hydraulic potential under hydrostatic equilibrium. During unit-gradient flow, the matric potential corresponding to the mean curvature of the menisci should provide a good approximation of the intrinsic phase average of the matric potential.

Effects of IV Acetaminophen on Core Body Temperature and Hemodynamic Responses in Febrile Critically Ill Adults: A Randomized Controlled Trial.

PubMed

Schell-Chaple, Hildy M; Liu, Kathleen D; Matthay, Michael A; Sessler, Daniel I; Puntillo, Kathleen A

2017-07-01

To determine the effects of IV acetaminophen on core body temperature, blood pressure, and heart rate in febrile critically ill patients. Randomized, double-blind, placebo-controlled clinical trial. Three adult ICUs at a large, urban, academic medical center. Forty critically ill adults with fever (core temperature, ≥ 38.3°C). An infusion of acetaminophen 1 g or saline placebo over 15 minutes. Core temperature and vital signs were measured at baseline and at 5-15-minute intervals for 4 hours after infusion of study drug. The primary outcome was time-weighted average core temperature adjusted for baseline temperature. Secondary outcomes included adjusted time-weighted average heart rate, blood pressure, and respiratory rate, along with changes-over-time for each. Baseline patient characteristics were similar in those given acetaminophen and placebo. Patients given acetaminophen had an adjusted time-weighted average temperature that was 0.47°C less than those given placebo (95% CI, -0.76 to -0.18; p = 0.002). The acetaminophen group had significantly lower adjusted time-weighted average systolic blood pressure (-17 mm Hg; 95% CI, -25 to -8; p < 0.001), mean arterial pressure (-7 mm Hg; 95% CI, -12 to -1; p = 0.02), and heart rate (-6 beats/min; 95% CI, -10 to -1; p = 0.03). Changes-over-time temperature, blood pressure, and heart rate outcomes were also significantly lower at 2 hours, but not at 4 hours. Among febrile critically ill adults, treatment with acetaminophen decreased temperature, blood pressure, and heart rate. IV acetaminophen thus produces modest fever reduction in critical care patients, along with clinically important reductions in blood pressure.

Analysis of actual pressure point using the power flexible capacitive sensor during chest compression.

PubMed

Minami, Kouichiro; Kokubo, Yota; Maeda, Ichinosuke; Hibino, Shingo

2017-02-01

In chest compression for cardiopulmonary resuscitation (CPR), the lower half of the sternum is pressed according to the American Heart Association (AHA) guidelines 2010. These have been no studies which identify the exact location of the applied by individual chest compressions. We developed a rubber power-flexible capacitive sensor that could measure the actual pressure point of chest compression in real time. Here, we examined the pressure point of chest compression by ambulance crews during CPR using a mannequin. We included 179 ambulance crews. Chest compression was performed for 2 min. The pressure position was monitored, and the quality of chest compression was analyzed by using a flexible pressure sensor (Shinnosukekun™). Of the ambulance crews, 58 (32.4 %) pressed the center and 121 (67.6 %) pressed outside the proper area of chest compression. Many of them pressed outside the center; 8, 7, 41, and 90 pressed on the caudal, left, right, and cranial side, respectively. Average compression rate, average recoil, average depth, and average duty cycle were 108.6 counts per minute, 0.089, 4.5 cm, and 48.27 %, respectively. Many of the ambulance crews did not press on the sternal lower half definitely. This new device has the potential to improve the quality of CPR during training or in clinical practice.

Evaluation of Glaucoma Progression in Large-Scale Clinical Data: The Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG).

PubMed

Fujino, Yuri; Asaoka, Ryo; Murata, Hiroshi; Miki, Atsuya; Tanito, Masaki; Mizoue, Shiro; Mori, Kazuhiko; Suzuki, Katsuyoshi; Yamashita, Takehiro; Kashiwagi, Kenji; Shoji, Nobuyuki

2016-04-01

To develop a large-scale real clinical database of glaucoma (Japanese Archive of Multicentral Databases in Glaucoma: JAMDIG) and to investigate the effect of treatment. The study included a total of 1348 eyes of 805 primary open-angle glaucoma patients with 10 visual fields (VFs) measured with 24-2 or 30-2 Humphrey Field Analyzer (HFA) and intraocular pressure (IOP) records in 10 institutes in Japan. Those with 10 reliable VFs were further identified (638 eyes of 417 patients). Mean total deviation (mTD) of the 52 test points in the 24-2 HFA VF was calculated, and the relationship between mTD progression rate and seven variables (age, mTD of baseline VF, average IOP, standard deviation (SD) of IOP, previous argon/selective laser trabeculoplasties (ALT/SLT), previous trabeculectomy, and previous trabeculotomy) was analyzed. The mTD in the initial VF was -6.9 ± 6.2 dB and the mTD progression rate was -0.26 ± 0.46 dB/year. Mean IOP during the follow-up period was 13.5 ± 2.2 mm Hg. Age and SD of IOP were related to mTD progression rate. However, in eyes with average IOP below 15 and also 13 mm Hg, only age and baseline VF mTD were related to mTD progression rate. Age and the degree of VF damage were related to future progression. Average IOP was not related to the progression rate; however, fluctuation of IOP was associated with faster progression, although this was not the case when average IOP was below 15 mm Hg.

Ready to work or not quite? Self-perception of practical skills among medical students from Serbia ahead of graduation.

PubMed

Gazibara, Tatjana; Nurković, Selmina; Marić, Gorica; Kurtagić, Ilma; Kovačević, Nikolina; Kisić-Tepavčević, Darija; Pekmezović, Tatjana

2015-08-01

To assess final year medical students' self-perception of their practical skills. The study was conducted at the Faculty of Medicine in Belgrade during compulsory practical sessions in the period December 2-9, 2013 and 390 students agreed to participate (response rate 77.8%). The questionnaire included questions on demographic characteristics, 21 questions on students' self-perception of their practical skills, and 1 question on students' self-perceived readiness to start working with patients. Cronbach's α for the entire scale was 0.891. Students felt most confident about measuring arterial pulse and blood pressure and taking patients' history (average score 10 for all three skills) and least confident about placing a urinary catheter (average score 1) and suturing a wound (average score 2). They rated their readiness to work with patients with 5.0 out of 10.0 points. The total score did not correlate with students' average mark (Spearman's ρ=0.039; P=0.460) and the average mark did not correlate with the self-perceived readiness to work with patients (Spearman's ρ=-0.048; P=0.365). Our study suggests that medical students lack confidence to perform various clinical procedures, particularly those related to surgical interventions. To improve students' confidence, clinical curriculum should include either more hours of practical work or ensure closer supervision of practical training in wards.

An Evaluation of Surgical Functional Reconstruction of the Foot Using Kinetic and Kinematic Systems: A Case Report.

PubMed

Jordán-Palomar, Elena Irene; Javierre, Etelvina; Rey-Vasalo, José; Alfaro-Santafé, Víctor; Gómez-Benito, María José

Most pedobarographic studies of microsurgical foot reconstruction have been retrospective. In the present study, we report the results from a prospective pedobarographic study of a patient after microsurgical reconstruction of her foot with a latissimus dorsi flap and a cutaneous paddle, with a 42-month follow-up period. We describe the foot reconstruction plan and the pedobarographic measurements and analyzed its functional outcome. The goal of the present study was to demonstrate that pedobarography could have a role in the treatment of foot reconstruction from a quantitative perspective. The pedobarographic measurements were recorded after the initial coverage surgery and 2 subsequent foot remodeling procedures. A total of 4 pedobarographic measurements and 2 gait analyses were recorded and compared for both the noninvolved foot and the injured foot. Furthermore, the progress of the reconstructed foot was critically evaluated using this method. Both static and dynamic patterns were compared at subsequent follow-up visits after the foot reconstruction. The values and progression of the foot shape, peak foot pressure (kPa), average foot pressure (kPa), total contact surface (cm 2 ), loading time (%), and step time (ms) were recorded. Initially, the pressure distribution of the reconstructed foot showed higher peak values at nonanatomic locations, revealing a greater ulceration risk. Over time, we found an improvement in the shape and values of these factors in the involved foot. To homogenize the pressure distribution and correct the imbalance between the 2 feet, patient-specific insoles were designed and fabricated. In our patient, pedobarography provided an objective, repeatable, and recordable method for the evaluation of the reconstructed foot. Pedobarography can therefore provide valuable insights into the prevention of pressure ulcers and optimization of rehabilitation. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Mammographic compression after breast conserving therapy: Controlling pressure instead of force

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groot, J. E. de, E-mail: jerry.degroot@sigmascreening.com; Branderhorst, W.; Grimbergen, C. A.

Purpose: X-ray mammography is the primary tool for early detection of breast cancer and for follow-up after breast conserving therapy (BCT). BCT-treated breasts are smaller, less elastic, and more sensitive to pain. Instead of the current force-controlled approach of applying the same force to each breast, pressure-controlled protocols aim to improve standardization in terms of physiology by taking breast contact area and inelasticity into account. The purpose of this study is to estimate the potential for pressure protocols to reduce discomfort and pain, particularly the number of severe pain complaints for BCT-treated breasts. Methods: A prospective observational study including 58more » women having one BCT-treated breast and one untreated nonsymptomatic breast, following our hospital's 18 decanewton (daN) compression protocol was performed. Breast thickness, applied force, contact area, mean pressure, breast volume, and inelasticity (mean E-modulus) were statistically compared between the within-women breast pairs, and data were used as predictors for severe pain, i.e., scores 7 and higher on an 11-point Numerical Rating Scale. Curve-fitting models were used to estimate how pressure-controlled protocols affect breast thickness, compression force, and pain experience. Results: BCT-treated breasts had on average 27% smaller contact areas, 30% lower elasticity, and 30% higher pain scores than untreated breasts (allp < 0.001). Contact area was the strongest predictor for severe pain (p < 0.01). Since BCT-treatment is associated with an average 0.36 dm{sup 2} decrease in contact area, as well as increased pain sensitivity, BCT-breasts had on average 5.3 times higher odds for severe pain than untreated breasts. Model estimations for a pressure-controlled protocol with a 10 kPa target pressure, which is below normal arterial pressure, suggest an average 26% (range 10%–36%) reduction in pain score, and an average 77% (range 46%–95%) reduction of the odds for severe pain. The estimated increase in thickness is +6.4% for BCT breasts. Conclusions: After BCT, women have hardly any choice in avoiding an annual follow-up mammogram. Model estimations show that a 10 kPa pressure-controlled protocol has the potential to reduce pain and severe pain particularly for these women. The results highly motivate conducting further research in larger subject groups.« less

Scanning the pressure-induced distortion of fingerprints.

PubMed

Mil'shtein, S; Doshi, U

2004-01-01

Fingerprint recognition technology is an important part of criminal investigations it is the basis of some security systems and an important tool of government operations such as the Immigration and Naturalization Services, registration procedures in the Armed Forces, and so forth. After the tragic events of September 11, 2001, the importance of reliable fingerprint recognition technology became even more obvious. In the current study, pressure-induced changes of distances between ridges of a fingerprint were measured. Using calibrated silicon pressure sensors we scanned the distribution of pressure across a finger pixel by pixel, and also generated maps of an average pressure distribution during fingerprinting. Emulating the fingerprinting procedure employed with widely used optical scanners, we found that on average the distance between ridges decreases by about 20% when a finger is positioned on a scanner. Controlled loading of a finger demonstrated that it is impossible to reproduce the same distribution of pressure across a given finger during repeated fingerprinting procedures.

Atmospheric Pressure and Onset of Episodes of Menière’s Disease - A Repeated Measures Study

PubMed Central

Strobl, Ralf; Heinlin, Nina; Krause, Eike; Olzowy, Bernhard; Koppe, Christina; Grill, Eva

2016-01-01

Background External changes of air pressure are transmitted to the middle and inner ear and may be used therapeutically in Menière’s disease, one of the most common vertigo disorders. We analyzed the possible relationship of atmospheric pressure and other meteorological parameters with the onset of MD vertigo episodes in order to determine whether atmospheric pressure changes play a role in the occurrence of MD episodes. Methods Patients of a tertiary outpatient dizziness clinic diagnosed with MD were asked to keep a daily vertigo diary to document MD episodes (2004–2009). Local air pressure, absolute temperature and dew point temperature were acquired on an hourly basis. Change in meteorological parameters was conceptualized as the maximum difference in a 24 hour time frame preceding each day. Effects were estimated using additive mixed models with a random participant effect. We included lagged air parameters, age, sex, weekday and season in the model. Results A total of 56 persons (59% female) with mean age 54 years were included. Mean follow-up time was 267 days. Persons experienced on average 10.3 episodes during the observation period (median 8). Age and change in air pressure were significantly associated with vertigo onset risk (Odds Ratio = 0.979 and 1.010). We could not show an effect of sex, weekday, season, air temperature, and dew point temperature. Conclusions Change in air pressure was significantly associated with onset of MD episodes, suggesting a potential triggering mechanism in the inner ear. MD patients may possibly use air pressure changes as an early warning system for vertigo attacks in the future. PMID:27096752

Piloted Ignition Delay of PMMA in Space Exploration Atmospheres

NASA Technical Reports Server (NTRS)

McAllister, Sara; Fernandez-Pello, Carlos; Urban, David; Ruff, Gary

2007-01-01

In order to reduce the risk of decompression sickness associated with extravehicular activity (EVA), NASA is designing the next generation of exploration vehicles and habitats with a different cabin environment than used previously. The proposed environment uses a total cabin pressure of 52.7 to 58.6 kPa with an oxygen concentration of 30 to 34% by volume and was chosen with material flammability in mind. Because materials may burn differently under these conditions and there is little information on how this new environment affects the flammability of the materials onboard, it is important to conduct material flammability experiments at the intended exploration atmosphere. One method to evaluate material flammability is by its ease of ignition. To this end, piloted ignition delay tests were conducted in the Forced Ignition and Spread Test (FIST) apparatus subject to this new environment. In these tests, polymethylmethacylate (PMMA) was exposed to a range of oxidizer flow velocities and externally applied heat fluxes. Tests were conducted for a baseline case of normal pressure and oxygen concentration, low pressure (58.6 kPa) with normal oxygen (21%), and low pressure with 32% oxygen concentration conditions to determine the individual effect of pressure and the combined effect of pressure and oxygen concentration on the ignition delay. It was found that reducing the pressure while keeping the oxygen concentration at 21% reduced the ignition time by 17% on average. Increasing the oxygen concentration at low pressures reduced the ignition time by an additional 10%. It was also noted that the critical heat flux for ignition decreases at exploration atmospheres. These results show that tests conducted in standard atmospheric conditions will underpredict the ignition of materials intended for use on spacecraft and that, at these conditions, materials are more susceptible to ignition than at current spacecraft atmospheres.

[Quantitative evaluation of resource and environment pressure in Qinghai Province, China based on footprint family].

PubMed

Ma, Cai Hong; Zhao, Jing

2016-04-22

In order to effectively evaluate the influence of human activities on the resource and environment, this paper constructed an resource and environment pressure evaluation system based on footprint family, and calculated the ecological footprint, carbon footprint, water footprint, and resource and environment pressure in Qinghai Province. The results showed that from 1990 to 2013, the ecological footprint per capita in Qinghai Province increased from 1.32 hm 2 to 3.32 hm 2 , and biological capacity per capita decreased from 2.33 hm 2 to 2.07 hm 2 . Since 2006 there was ecological deficit. However, the biomass surplus existed during 1990-2013. The carbon footprint per capita increased from 5.82 t to 15.85 t, which had been more than 7.93 times of the target to address climate change. The water footprint per capita decreased from 967.67 m 3 to 732.05 m 3 . Since 1990, the ecological pressure was at low grade (1 b ), greenhouse gas (GHG) emissions pressure was enhanced from low grade (1 b ) to above-average grade (2 b ), the water pressure was at very low grade (1 a ), the resource and environment pressure increased from very low grade (1 a ) to low grade (1 b ). The rate of contribution of ecological pressure and water resource pressure to resources and environment pressure gradually decreased, whereas, the rate of contribution of GHG emission pressure to resources and environment pressure gradually increased. The resource and environment pressure had spatial heterogeneity. In 2013, it was at very high grade (3 b ) in Xining City, at above-average grade (2 b ) in Haidong City, at below-average grade (2 a ) in Haixi State and atvery low grade (1 a ) in the rest regions. The main resource and environment pressure source also had obvious spatial heterogeneity. In future, differentiation strategies should be taken in the decompression progress.

The effects of flow on airway pressure during nasal high-flow oxygen therapy.

PubMed

Parke, Rachael L; Eccleston, Michelle L; McGuinness, Shay P

2011-08-01

Nasal high-flow oxygen therapy increases the mean nasopharyngeal airway pressure in adults, but the relationship between flow and pressure is not well defined. To determine the relationship between flow and pressure with the Optiflow nasal high-flow oxygen therapy system. We invited patients scheduled for elective cardiac surgery to participate. Measurements were performed with nasal high-flow oxygen at flows of 30, 40, and 50 L/min, with the patient's mouth both open and closed. Pressures were recorded over one minute of breathing, and average flows were calculated via simple averaging. With the mouth closed, the mean ± SD airway pressures at 30, 40, and 50 L/min were 1.93 ± 1.25 cm H(2)O, 2.58 ± 1.54 cm H(2)O, and 3.31 ± 1.05 cm H(2)O, respectively. There was a positive linear relationship between flow and pressure. The mean nasopharyngeal pressure during nasal high-flow oxygen increases as flow increases. Australian Clinical Trials Registry http://www.adhb.govt.nz/achicu/hot_2_airway_pressure.htm.

The Dynamics of Glomerular Ultrafiltration in the Rat

PubMed Central

Brenner, Barry M.; Troy, Julia L.; Daugharty, Terrance M.

1971-01-01

Using a unique strain of Wistar rats endowed with glomeruli situated directly on the renal cortical surface, we measured glomerular capillary pressures using servo-nulling micropipette transducer techniques. Pressures in 12 glomerular capillaries from 7 rats averaged 60 cm H2O, or approximately 50% of mean systemic arterial values. Wave form characteristics for these glomerular capillaries were found to be remarkably similar to those of the central aorta. From similarly direct estimates of hydrostatic pressures in proximal tubules, and colloid osmotic pressures in systemic and efferent arteriolar plasmas, the net driving force for ultrafiltration was calculated. The average value of 14 cm H2O is lower by some two-thirds than the majority of estimates reported previously based on indirect techniques. Single nephron GFR (glomerular filtration rate) was also measured in these rats, thereby permitting calculation of the glomerular capillary ultrafiltration coefficient. The average value of 0.044 nl sec−1 cm H2O−1 glomerulus−1 is at least fourfold greater than previous estimates derived from indirect observations. PMID:5097578

Root-Knot Nematode Management in Double-Cropped Plasticulture Vegetables

PubMed Central

Desaeger, J. A.; Csinos, A. S.

2006-01-01

Combination treatments of chisel-injected fumigants (methyl bromide, 1,3-D, metam sodium, and chloropicrin) on a first crop, followed by drip-applied fumigants (metam sodium and 1,3-D ± chloropicrin) on a second crop, with and without oxamyl drip applications were evaluated for control of Meloidogyne incognita in three different tests (2002 to 2004) in Tifton, GA. First crops were eggplant or tomato, and second crops were cantaloupe, squash, or jalapeno pepper. Double-cropped vegetables suffered much greater root-knot nematode (RKN) pressure than first crops, and almost-total yield loss occurred when second crops received no nematicide treatment. On a first crop of eggplant, all fumigants provided good nematode control and average yield increases of 10% to 15 %. On second crops, higher application rates and fumigant combinations (metam sodium and 1,3-D ± chloropicrin) improved RKN control and increased yields on average by 20% to 35 % compared to the nonfumigated control. Oxamyl increased yields of the first crop in 2003 on average by 10% to 15% but had no effect in 2004 when RKN failed to establish itself. On double-cropped squash in 2003, oxamyl following fumigation provided significant additional reduction in nematode infection and increased squash yields on average by 30% to 75%. PMID:19259431

Effect of Geometric Parameters on the Performance of Second Throat Annular Steam Ejectors

DTIC Science & Technology

1991-07-01

Cell Pressure versus Rake Average Exit Pitot Pressure . . . . . . . . . . . 42 15. Baseline Wall Pressure Profiles...diffuser exit plane pitot pressure rake . 2.5.2 Alternate Configurations Six alternate ejector diffuser configurations were tested. A summary of...along the walls of the diffusers to help characterize the flow. The ejector diffuser exit pitot pressure was measured with a 6-probe pitot pressure rake

Pressure Effects on Oxygen Concentration Flammability Thresholds of Materials for Aerospace Applications

NASA Technical Reports Server (NTRS)

Hirsch, David; Williams, Jim; Beeson, Harold

2006-01-01

Spacecraft materials selection is based on an upward flammability test conducted in a quiescent environment in the highest-expected oxygen-concentration environment. However, NASA s advanced space exploration program is anticipating using various habitable environments. Because limited data is available to support current program requirements, a different test logic is suggested to address these expanded atmospheric environments through the determination of materials self-extinguishment limits. This paper provides additional pressure effects data on oxygen concentration and partial pressure self-extinguishment limits under quiescent conditions. For the range of total pressures tested, the oxygen concentration and oxygen partial pressure flammability thresholds show a near linear function of total pressure. The oxygen concentration/oxygen partial pressure flammability thresholds depend on the total pressure and appear to increase with increasing oxygen concentration (and oxygen partial pressure). For the Constellation Program, the flammability threshold information will allow NASA to identify materials with increased flammability risk because of oxygen concentration and total pressure changes, minimize potential impacts, and allow for development of sound requirements for new spacecraft and extraterrestrial landers and habitats.

Determination of mean pressure from PIV in compressible flows using the Reynolds-averaging approach

NASA Astrophysics Data System (ADS)

van Gent, Paul L.; van Oudheusden, Bas W.; Schrijer, Ferry F. J.

2018-03-01

The feasibility of computing the flow pressure on the basis of PIV velocity data has been demonstrated abundantly for low-speed conditions. The added complications occurring for high-speed compressible flows have, however, so far proved to be largely inhibitive for the accurate experimental determination of instantaneous pressure. Obtaining mean pressure may remain a worthwhile and realistic goal to pursue. In a previous study, a Reynolds-averaging procedure was developed for this, under the moderate-Mach-number assumption that density fluctuations can be neglected. The present communication addresses the accuracy of this assumption, and the consistency of its implementation, by evaluating of the relevance of the different contributions resulting from the Reynolds-averaging. The methodology involves a theoretical order-of-magnitude analysis, complemented with a quantitative assessment based on a simulated and a real PIV experiment. The assessments show that it is sufficient to account for spatial variations in the mean velocity and the Reynolds-stresses and that temporal and spatial density variations (fluctuations and gradients) are of secondary importance and comparable order-of-magnitude. This result permits to simplify the calculation of mean pressure from PIV velocity data and to validate the approximation of neglecting temporal and spatial density variations without having access to reference pressure data.

Associations of long-term fine particulate matter exposure with prevalent hypertension and increased blood pressure in older Americans.

PubMed

Honda, Trenton; Pun, Vivian C; Manjourides, Justin; Suh, Helen

2018-07-01

Hypertension is a highly prevalent cardiovascular risk factor. It is possible that air pollution, also an established cardiovascular risk factor, may contribute to cardiovascular disease through increasing blood pressure. Previous studies evaluating associations between air pollution and blood pressure have had mixed results. We examined the association between long-term (one-year moving average) air pollutant exposures, prevalent hypertension and blood pressure in 4121 older Americans (57+ years) enrolled in the National Social Life, Health, and Aging Project. We estimated exposures to PM 2.5 using spatio-temporal models and used logistic regression accounting for repeated measures to evaluate the association between long-term average PM 2.5 and prevalence odds of hypertension. We additionally used linear regression to evaluate the associations between air pollutants and systolic, diastolic, mean arterial, and pulse pressures. Health effect models were adjusted for a number of demographic, health and socioeconomic covariates. An inter-quartile range (3.91 μg/m 3 ) increase in the one-year moving average of PM 2.5 was associated with increased: Odds of prevalent hypertension (POR 1.24, 95% CI: 1.11, 1.38), systolic blood pressure (0.93 mm Hg, 95% CI: 0.05, 1.80) and pulse pressure (0.89 mm Hg, 95% CI: 0.21, 1.58). Dose-response relationships were also observed. PM 2.5 was associated with increased odds of prevalent hypertension, and increased systolic pressure and pulse pressure in a cohort of older Americans. These findings add to the growing evidence that air pollution may be an important risk factor for hypertension and perturbations in blood pressure. Copyright © 2018 Elsevier Inc. All rights reserved.

Hydro-isomerization of n-hexane on bi-functional catalyst: Effect of total and hydrogen partial pressures

NASA Astrophysics Data System (ADS)

Thoa, Dao Thi Kim; Loc, Luu Cam

2017-09-01

The effect of both total pressure and hydrogen partial pressure during n-hexane hydro-isomerization over platinum impregnated on HZSM-5 was studied. n-Hexane hydro-isomerization was conducted at atmospheric pressure and 0.7 MPa to observe the influence of total pressure. In order to see the effect of hydrogen partial pressure, the reaction was taken place at different partial pressure of hydrogen varied from 307 hPa to 718 hPa by dilution with nitrogen to keep the total pressure at 0.1 MPa. Physico-chemical characteristics of catalyst were determined by the methods of nitrogen physi-sorption BET, SEM, XRD, TEM, NH3-TPD, TPR, and Hydrogen Pulse Chemi-sorption. Activity of catalyst in the hydro-isomerization of n-hexane was studied in a micro-flow reactor in the temperature range of 225-325 °C; the molar ratio H2/ hydrocarbon: 5.92, concentration of n-hexane: 9.2 mol.%, GHSV 2698 h-1. The obtained catalyst expressed high acid density, good reducing property, high metal dispersion, and good balance between metallic and acidic sites. It is excellent contact for n-hexane hydro-isomerization. At 250 °C, n-hexane conversion and selectivity were as high as 59-76 % and 85-99 %, respectively. It was found that catalytic activity was promoted either by total pressure or hydrogen partial pressure. At total pressure of 0.7 MPa while hydrogen partial pressure of 718 hPa, catalyst produced 63 RON liquid product containing friendly environmental iso-paraffins which is superior blending stock for green gasoline. Hydrogen did not only preserve catalyst actives by depressing hydrocracking and removing coke precursors but also facilitated hydride transfer step in the bi-functional bi-molecular mechanism.

Mapping Atmospheric Moisture Climatologies across the Conterminous United States

PubMed Central

Daly, Christopher; Smith, Joseph I.; Olson, Keith V.

2015-01-01

Spatial climate datasets of 1981–2010 long-term mean monthly average dew point and minimum and maximum vapor pressure deficit were developed for the conterminous United States at 30-arcsec (~800m) resolution. Interpolation of long-term averages (twelve monthly values per variable) was performed using PRISM (Parameter-elevation Relationships on Independent Slopes Model). Surface stations available for analysis numbered only 4,000 for dew point and 3,500 for vapor pressure deficit, compared to 16,000 for previously-developed grids of 1981–2010 long-term mean monthly minimum and maximum temperature. Therefore, a form of Climatologically-Aided Interpolation (CAI) was used, in which the 1981–2010 temperature grids were used as predictor grids. For each grid cell, PRISM calculated a local regression function between the interpolated climate variable and the predictor grid. Nearby stations entering the regression were assigned weights based on the physiographic similarity of the station to the grid cell that included the effects of distance, elevation, coastal proximity, vertical atmospheric layer, and topographic position. Interpolation uncertainties were estimated using cross-validation exercises. Given that CAI interpolation was used, a new method was developed to allow uncertainties in predictor grids to be accounted for in estimating the total interpolation error. Local land use/land cover properties had noticeable effects on the spatial patterns of atmospheric moisture content and deficit. An example of this was relatively high dew points and low vapor pressure deficits at stations located in or near irrigated fields. The new grids, in combination with existing temperature grids, enable the user to derive a full suite of atmospheric moisture variables, such as minimum and maximum relative humidity, vapor pressure, and dew point depression, with accompanying assumptions. All of these grids are available online at http://prism.oregonstate.edu, and include 800-m and 4-km resolution data, images, metadata, pedigree information, and station inventory files. PMID:26485026

What happens at work stays at work? Workplace supervisory social interactions and blood pressure outcomes.

PubMed

Wong, Jennifer H K; Kelloway, E Kevin

2016-04-01

We investigated the relationship between workplace supervisory social interactions and blood pressure outcomes using hourly diary entries and ambulatory blood pressure data from an experience sampling study of 55 long-term care employees. After accounting for relevant cardiovascular controls, significant effects of supervisory interactions on cardiovascular reactivity and recovery were found. Multilevel analyses revealed that negatively perceived supervisory interactions predicted higher systolic blood pressure at work (B = -1.59, p < .05, N observations = 422). Using time-lagged hierarchical regression analyses, the average perceived valence of supervisory interactions at work predicted average systolic blood pressure recovery after work (B = -14.52, p < .05, N = 33). Specifically, negatively perceived supervisory interactions at work predicted poorer cardiovascular recovery after work. Suggestions for improving practices in organizations and in experience sampling research are discussed. (c) 2016 APA, all rights reserved).

Methods of increasing thermal efficiency of steam and gas turbine plants

NASA Astrophysics Data System (ADS)

Vasserman, A. A.; Shutenko, M. A.

2017-11-01

Three new methods of increasing efficiency of turbine power plants are described. Increasing average temperature of heat supply in steam turbine plant by mixing steam after overheaters with products of combustion of natural gas in the oxygen. Development of this idea consists in maintaining steam temperature on the major part of expansion in the turbine at level, close to initial temperature. Increasing efficiency of gas turbine plant by way of regenerative heating of the air by gas after its expansion in high pressure turbine and before expansion in the low pressure turbine. Due to this temperature of air, entering combustion chamber, is increased and average temperature of heat supply is consequently increased. At the same time average temperature of heat removal is decreased. Increasing efficiency of combined cycle power plant by avoiding of heat transfer from gas to wet steam and transferring heat from gas to water and superheated steam only. Steam will be generated by multi stage throttling of the water from supercritical pressure and temperature close to critical, to the pressure slightly higher than condensation pressure. Throttling of the water and separation of the wet steam on saturated water and steam does not require complicated technical devices.

Total and methyl mercury contents and distribution characteristics in cicada, Cryptotympana atrata (Fabricius).

PubMed

Zheng, Dongmei; Zhang, Zhongsheng; Wang, Qichao

2010-06-01

Total and methyl mercury concentrations of cicada bodies, wings, and exuviae were investigated to study the mercury distribution characteristics. Results indicated that total and methyl mercury concentrations of cicada bodies were 2.64 mg/kg and 123.93 ng/g on average, respectively. In cicada tissues, total mercury concentrations were found to increase in the order of exuviae (0.50 mg/kg on average) < wings (0.98 mg/kg on average) < cicada bodies (2.64 mg/kg on average) and methyl mercury concentrations of cicada bodies were 123.93 ng/g on average and were the highest. Methyl mercury concentrations accounted for about 4.69% of total mercury in cicada bodies and most mercury was in inorganic forms in cicada. Sex differences of total mercury concentrations were significantly great (F = 8.433, p < 0.01) and total mercury concentrations of the males, which were 3.38 mg/kg on average, were much higher. Correlation analysis showed that neither total nor methyl mercury concentrations of cicada bodies was significantly related to the corresponding contents of soil (r = 0.0598, p > 0.05).

Mechanical support of total cavopulmonary connection with an axial flow pump.

PubMed

Riemer, R Kirk; Amir, Gabriel; Reichenbach, Steven H; Reinhartz, Olaf

2005-08-01

Even under optimal circumstances, total cavopulmonary connection is associated with a continuous late risk of death. Hemodynamics are distinctly abnormal, with increased systemic venous pressures and frequent low cardiac output. Our study uses a sheep model of total cavopulmonary connection to test the response to axial flow pump (Thoratec HeartMate II; Thoratec Corporation (Pleasanton, Calif)) support of total cavopulmonary connection, which might be suitable to treat patients with failing Fontan circulation. Eight sheep (42-48 kg) were studied. After pilot studies in 3 animals, 5 underwent both pump-supported and nonsupported total cavopulmonary connection in alternating sequence for up to 2 hours. This was achieved with a 12-mm polytetrafluoroethylene graft from the (distally ligated) superior vena cava to the main pulmonary artery and a cannula placed in the inferior vena cava with an attached 16-mm Dacron graft to the main pulmonary artery. Pressures (arterial, inferior vena cava, left atrium, and pulmonary artery) and flows (ascending aorta and inferior vena cava) were recorded over 1 hour both with unsupported total cavopulmonary connection and after placing an axial flow pump (Thoratec HeartMate II) between the inferior vena caval inflow cannula and the main pulmonary artery. Under nonsupported total cavopulmonary connection circulation, inferior vena caval and aortic blood flow decreased by nearly 50%. Inferior vena caval pressure nearly doubled, whereas arterial pressure decreased by one third. Pulmonary artery pressure became nonpulsatile; however, mean pulmonary artery pressure and left atrial pressure did not change significantly. With pump-supported Fontan circulation, cardiac output, inferior vena caval flow, and arterial pressure returned to baseline. Inferior vena caval pressure decreased to below baseline levels. Mean pulmonary artery pressure and left atrial pressure again remained unchanged. Axial flow pump support from the inferior vena cava to the pulmonary artery can prevent the substantial decrease of aortic flow and pressure associated with total cavopulmonary connection and can reverse its poor hemodynamics. This is a simple model that can be used to further evaluate the potential of mechanical support as a treatment option in failing Fontan circulation.

The Worksite Heart Health Improvement Project (WHHIP): feasibility and efficacy.

PubMed

Flannery, Kelly; Resnick, Barbara; Galik, Elizabeth; Lipscomb, Jane; McPhaul, Kathleen; Shaughnessy, Marianne

2012-01-01

Test the feasibility and efficacy of the Worksite Heart Health Improvement Project (WHHIP). The WHHIP was a quasi-experimental 6-month pilot performed in 2 long-term care facilities. Thirty-nine female minority nursing assistants participated in this study with a mean age of 42.39 (SD = 12.79) years. Measures were collected at baseline, 3, and 6 months and included blood pressure, lipid panel, body mass index, physical activity levels, diet behaviors, depressive symptoms, and self-efficacy outcomes. The 3-month WHHIP intervention included 3 components: environmental and policy assessment; education; and on-going motivation. The control site received education only. Subject participation averaged 47% and 58% in exercise and diet related activities, respectively. Generalized estimating equations showed the treatment group showed significant improvements in depressive symptoms (p = .012), systolic blood pressure (p = .028), total cholesterol (p = .002) and triglycerides (p = .011) over time. The treatment group also showed trends for improvement in diet behaviors (p = .069) and diastolic blood pressure (p = .073). This study provided feasibility evidence for the WHHIP and preliminary evidence that the WHHIP can improve heart healthy behaviors and subsequent outcomes among nursing assistants in long-term care settings. © 2012 Wiley Periodicals, Inc.

Grid-Adapted FUN3D Computations for the Second High Lift Prediction Workshop

NASA Technical Reports Server (NTRS)

Lee-Rausch, E. M.; Rumsey, C. L.; Park, M. A.

2014-01-01

Contributions of the unstructured Reynolds-averaged Navier-Stokes code FUN3D to the 2nd AIAA CFD High Lift Prediction Workshop are described, and detailed comparisons are made with experimental data. Using workshop-supplied grids, results for the clean wing configuration are compared with results from the structured code CFL3D Using the same turbulence model, both codes compare reasonably well in terms of total forces and moments, and the maximum lift is similarly over-predicted for both codes compared to experiment. By including more representative geometry features such as slat and flap brackets and slat pressure tube bundles, FUN3D captures the general effects of the Reynolds number variation, but under-predicts maximum lift on workshop-supplied grids in comparison with the experimental data, due to excessive separation. However, when output-based, off-body grid adaptation in FUN3D is employed, results improve considerably. In particular, when the geometry includes both brackets and the pressure tube bundles, grid adaptation results in a more accurate prediction of lift near stall in comparison with the wind-tunnel data. Furthermore, a rotation-corrected turbulence model shows improved pressure predictions on the outboard span when using adapted grids.

Thermodynamic Behavior in Decaying Compressible Turbulence with Initially Dominant Temperature Fluctuations

NASA Astrophysics Data System (ADS)

Cai, X. D.; O'Brien, Edward E.; Ladeinde, Foluso

1996-11-01

Direct numerical simulation of decaying, isotropic, compressible turbulence in three dimensions is used to examine the behavior of fluctuations in density, temperature, and pressure when the initial conditions include temperature fluctuations larger than pressure fluctuations. The numerical procedure is described elsewhere (Ladeinde, F. et al.,) Phys. Fluids 7(11), pp. 2848 (1995), the initial turbulence Mach number range is subsonic, 0.3 to 0.7, and, following Ghosh and Matthaeus(Ghosh, S. and Matthaeus, W. H. Phys. Fluids A, pp. 148 (1991)), the initial compressible turbulence is characterized as a: mostly solenoidal, b: random, or c: longitudinal. These cases represent, respectively, ratios of initial kinetic energy in the compressible modes to total initial kinetic energy, say \\chi_0, which are either a: very small, b: about 0.6, or c: near unity. Thermodynamic scalings at the lowest values of initial Mach number and \\chi0 follow the predictions of Zank and Matthaeus (Zank, G. P. and Matthaeus, W. H. Phys. Fluids A(3), pp. 69 (1991)), but not otherwise. The relationship between \\chi, Mach number, and compressible pressure predicted by Sarkar et al.(Sarkar, S. et al.,) J. Fluid Mech. 227, pp. 473 (1991) applies, on average, to all cases computed.

Measurement of Flow Pattern Within a Rotating Stall Cell in an Axial Compressor

NASA Technical Reports Server (NTRS)

Lepicovsky, Jan; Braunscheidel, Edward P.

2006-01-01

Effective active control of rotating stall in axial compressors requires detailed understanding of flow instabilities associated with this compressor regime. Newly designed miniature high frequency response total and static pressure probes as well as commercial thermoanemometric probes are suitable tools for this task. However, during the rotating stall cycle the probes are subjected to flow direction changes that are far larger than the range of probe incidence acceptance, and therefore probe data without a proper correction would misrepresent unsteady variations of flow parameters. A methodology, based on ensemble averaging, is proposed to circumvent this problem. In this approach the ensemble averaged signals acquired for various probe setting angles are segmented, and only the sections for probe setting angles close to the actual flow angle are used for signal recombination. The methodology was verified by excellent agreement between velocity distributions obtained from pressure probe data, and data measured with thermoanemometric probes. Vector plots of unsteady flow behavior during the rotating stall regime indicate reversed flow within the rotating stall cell that spreads over to adjacent rotor blade channels. Results of this study confirmed that the NASA Low Speed Axial Compressor (LSAC) while in a rotating stall regime at rotor design speed exhibits one stall cell that rotates at a speed equal to 50.6 percent of the rotor shaft speed.

In silico evolution of the Drosophila gap gene regulatory sequence under elevated mutational pressure.

PubMed

Chertkova, Aleksandra A; Schiffman, Joshua S; Nuzhdin, Sergey V; Kozlov, Konstantin N; Samsonova, Maria G; Gursky, Vitaly V

2017-02-07

Cis-regulatory sequences are often composed of many low-affinity transcription factor binding sites (TFBSs). Determining the evolutionary and functional importance of regulatory sequence composition is impeded without a detailed knowledge of the genotype-phenotype map. We simulate the evolution of regulatory sequences involved in Drosophila melanogaster embryo segmentation during early development. Natural selection evaluates gene expression dynamics produced by a computational model of the developmental network. We observe a dramatic decrease in the total number of transcription factor binding sites through the course of evolution. Despite a decrease in average sequence binding energies through time, the regulatory sequences tend towards organisations containing increased high affinity transcription factor binding sites. Additionally, the binding energies of separate sequence segments demonstrate ubiquitous mutual correlations through time. Fewer than 10% of initial TFBSs are maintained throughout the entire simulation, deemed 'core' sites. These sites have increased functional importance as assessed under wild-type conditions and their binding energy distributions are highly conserved. Furthermore, TFBSs within close proximity of core sites exhibit increased longevity, reflecting functional regulatory interactions with core sites. In response to elevated mutational pressure, evolution tends to sample regulatory sequence organisations with fewer, albeit on average, stronger functional transcription factor binding sites. These organisations are also shaped by the regulatory interactions among core binding sites with sites in their local vicinity.

Flight Test of 31.2 Diameter Modified Ringsail Parachute Deployed at Mach 1.39, Dynamic Pressure 11 Pounds per Square Foot

NASA Technical Reports Server (NTRS)

Preisser, John S.; Eckstrom, Clinton V.; Murrow, Harold N.

1967-01-01

A 31.2-foot (9.51 meter) nominal diameter (reference area 764 ft(exp 2) (71.0 m(exp 2)) ringsail parachute modified to provide 15-percent geometric porosity was flight tested while attached to a 201-pound mass (91.2 kilogram) instrumented payload as part of the rocket launch portion of the NASA Planetary Entry Parachute Program (PEPP). The parachute deployment was initiated by the firing of a mortar at a Mach number of 1.39 and a dynamic pressure of 11.0 lb/ft(exp 2) (527 newtons/m(exp 2)) at an altitude of 122,500 feet (37.3 kilometers). The parachute deployed to suspension-line stretch (snatch force) in 0.35 second, and 0.12 second later the drag force increase associated with parachute inflation began. The parachute inflated in 0.24 second to the full-open condition for a total elapsed opening time of 0.71 second. The maximum opening load of 3970 pounds (17,700 newtons) came at the time the parachute was just fully opened. During the deceleration period, the parachute exhibited an average drag coefficient of 0.52 and oscillations of the parachute canopy were less than 5 degrees. During the steady-state terminal descent portion of the test period, the average effective drag coefficient (based on vertical descent velocity) was 0.52.

An experimental study of the wall-pressure fluctuations beneath low Reynolds number turbulent boundary layers.

PubMed

Van Blitterswyk, Jared; Rocha, Joana

2017-02-01

A more complete understanding of the physical relationships, between wall-pressure and turbulence, is required for modeling flow-induced noise and developing noise reduction strategies. In this study, the wall-pressure fluctuations, induced by low Reynolds number turbulent boundary layers, are experimentally studied using a high-resolution microphone array. Statistical characteristics obtained using traditional cross-correlation and cross-spectra analyses are complimented with wall-pressure-velocity cross-spectra and wavelet cross-correlations. Wall-pressure-velocity correlations revealed that turbulent activity in the buffer layer contributes at least 40% of the energy to the wall-pressure spectrum at all measured frequencies. As Reynolds number increases, the low-frequency energy shifts from the buffer layer to the logarithmic layer, as expected for regions of uniform streamwise momentum formed by hairpin packets. Conditional cross-spectra suggests that the majority of broadband wall-pressure energy is concentrated within the packets, with the pressure signatures of individual hairpin vortices estimated to decay on average within traveling ten displacement thicknesses, and the packet signature is retained for up to seven boundary layer thicknesses on average.

Analysis of healthy sitting behavior: interface pressure distribution and subcutaneous tissue oxygenation.

PubMed

Reenalda, Jasper; Van Geffen, Paul; Nederhand, Marc; Jannink, Michiel; IJzerman, Maarten; Rietman, Hans

2009-01-01

Pressure ulcers are a large problem in individuals who use a wheelchair for their mobility and have limited trunk stability and motor function. Because no relation between interface pressure and pressure ulcer development has been established and no clinical threshold for pressure ulcer development can be given, looking at the sitting behavior of nondisabled individuals is important. Nondisabled individuals do not develop pressure ulcers because they continuously shift posture. We analyzed the sitting behavior of 25 nondisabled male subjects by using a combination of interface pressure measurement and subcutaneous tissue oxygenation measurement by means of the Oxygen to See. These subjects shifted posture on average 7.8 +/- 5.2 times an hour. These posture shifts were merely a combination of posture shifts in the frontal and sagittal plane. Subcutaneous oxygen saturation increased on average 2.2% with each posture adjustment, indicating a positive effect of posture shifts on tissue viability. The results of this study can be used as a reference for seating interventions aimed at preventing pressure ulcers. Changing the sitting load at least every 8 minutes is recommended for wheelchair users.

Pressure and temperature effects on degradation kinetics and storage stability of total anthocyanins in blueberry juice.

PubMed

Buckow, Roman; Kastell, Anja; Terefe, Netsanet Shiferaw; Versteeg, Cornelis

2010-09-22

The degradation kinetics of total anthocyanins in blueberry (Vaccinium myrtillus) juice were studied during thermal processing by treatment at selected temperatures (60-121 °C) and combined high pressure-temperature processing (100-700 MPa, 40-121 °C). Anthocyanin stability was also studied for several of these treatments during storage at 4, 25, and 40 °C. Both pressure and temperature increased d, the degradation rate of total anthocyanins in blueberry juice, meaning that at constant temperature, anthocyanins were more rapidly degraded with increasing pressure. For example, 32% degradation of anthocyanins was observed after 20 min heating at 100 °C and atmospheric pressure, whereas at 100 °C and 600 MPa, approximately 50% of total anthocyanins were lost. Degradation of anthocyanins was significantly accelerated with increasing storage temperatures. Combined pressure-temperature treatment of pasteurized juice led to a slightly faster degradation of total anthocyanins during storage compared to heat treatments at ambient pressure. Degradation of anthocyanins was best described by a 1.4th-order reaction at all conditions investigated. A mathematical model describing the degradation of blueberry anthocyanins in juice as a function of pressure, temperature, and treatment time is presented.

Longitudinal study of body mass index, dyslipidemia, hyperglycemia, and hypertension in 60,000 men and women in Sweden and Austria.

PubMed

Van Hemelrijck, Mieke; Ulmer, Hanno; Nagel, Gabriele; Peter, Raphael Simon; Fritz, Josef; Myte, Robin; van Guelpen, Bethany; Föger, Bernhard; Concin, Hans; Häggström, Christel; Stattin, Pär; Stocks, Tanja

2018-01-01

Obesity is suggested to underlie development of other metabolic aberrations, but longitudinal relationships between metabolic factors at various ages has not been studied in detail. Data from 27,379 men and 32,275 women with in total 122,940 health examinations in the Västerbotten Intervention Project, Sweden and the Vorarlberg Health Monitoring and Prevention Programme, Austria were used to investigate body mass index (BMI), mid-blood pressure, and fasting levels of glucose, triglycerides, and total cholesterol at baseline in relation to 10-year changes of these factors and weight. We included paired examinations performed 10±2 years apart and used them for longitudinal analysis with linear regression of changes between the ages 30 and 40, 40 and 50, or 50 and 60 years. Higher levels of BMI were associated with increases in glucose and mid-blood pressure as well as triglycerides levels, and, to a lesser extent, decreases in cholesterol levels. For instance, per 5 kg/m2 higher BMI at age 40, glucose at age 50 increased by 0.24 mmol/l (95%CI: 0.22-0.26) and mid-blood pressure increased by 1.54 mm Hg (95%CI: 1.35-1.74). The strongest association observed was between BMI at age 30 and mid-blood pressure, which was 2.12 mm Hg (95% CI: 1.79-2.45) increase over ten years per 5 kg/m2 higher BMI level. This association was observed at an age when blood pressure levels on average remained stable. Other associations than those with BMI at baseline were much weaker. However, triglyceride levels were associated with future glucose changes among individuals with elevated BMI, particularly in the two older age groups. BMI was most indicative of long-term changes in metabolic factors, and the strongest impact was observed for increases in blood pressure between 30 and 40 years of age. Our study supports that lifestyle interventions preventing metabolic aberrations should focus on avoiding weight increases.

Experimental techniques and computational methods toward the estimation of the effective two-phase flow coefficients and multi-scale heterogeneities of soils

NASA Astrophysics Data System (ADS)

Tsakiroglou, C. D.; Aggelopoulos, C. A.; Sygouni, V.

2009-04-01

A hierarchical, network-type, dynamic simulator of the immiscible displacement of water by oil in heterogeneous porous media is developed to simulate the rate-controlled displacement of two fluids at the soil column scale. A cubic network is constructed, where each node is assigned a permeability which is chosen randomly from a distribution function. The intensity of heterogeneities is quantified by the width of the permeability distribution function. The capillary pressure at each node is calculated by combining a generalized Leverett J-function with a Corey type model. Information about the heterogeneity of soils at the pore network scale is obtained by combining mercury intrusion porosimetry (MIP) data with back-scattered scanning electron microscope (BSEM) images [1]. In order to estimate the two-phase flow properties of nodes (relative permeability and capillary pressure functions, permeability distribution function) immiscible and miscible displacement experiments are performed on undisturbed soil columns. The transient responses of measured variables (pressure drop, fluid saturation averaged over five successive segments, solute concentration averaged over three cross-sections) are fitted with models accounting for the preferential flow paths at the micro- (multi-region model) and macro-scale (multi flowpath model) because of multi-scale heterogeneities [2,3]. Simulating the immiscible displacement of water by oil (drainage) in a large netork, at each time step, the fluid saturation and pressure of each node are calculated formulating mass balances at each node, accounting for capillary, viscous and gravity forces, and solving the system of coupled equations. At each iteration of the algorithm, the pressure drop is so selected that the total flow rate of the injected fluid is kept constant. The dynamic large-scale network simulator is used (1) to examine the sensitivity of the transient responses of the axial distribution of fluid saturation and total pressure drop across the network to the permeability distribution function, spatial correlations of permeability, and capillary number, and (2) to estimate the effective (up-scaled) relative permeability functions at the soil column scale. In an attempt to clarify potential effects of the permeability distribution and spatial permeability correlations on the transient responses of the pressure drop across a soil column, signal analysis with wavelets is performed [4] on experimental and simulated results. The transient variation of signal energy and frequency of pressure drop fluctuations at the wavelet domain are correlated with macroscopic properties such as the effective water and oil relative permeabilities of the porous medium, and microscopic properties such as the variation of the permeability distribution of oil-occupied nodes. Toward the solution of the inverse problem, a general procedure is suggested to identify macro-heterogeneities from the fast analysis of pressure drop signals. References 1. Tsakiroglou, C.D. and M.A. Ioannidis, "Dual porosity modeling of the pore structure and transport properties of a contaminated soil", Eur. J. Soil Sci., 59, 744-761 (2008). 2. Aggelopoulos, C.A., and C.D. Tsakiroglou, "Quantifying the Soil Heterogeneity from Solute Dispersion Experiments", Geoderma, 146, 412-424 (2008). 3. Aggelopoulos, C.A., and C.D. Tsakiroglou, "A multi-flow path approach to model immiscible displacement in undisturbed heterogeneous soil columns", J. Contam. Hydrol., in press (2009). 4. Sygouni, V., C.D. Tsakiroglou, and A.C. Payatakes, "Using wavelets to characterize the wettability of porous materials", Phys. Rev. E, 76, 056304 (2007).

Thermodynamic evaluation of transonic compressor rotors using the finite volume approach

NASA Technical Reports Server (NTRS)

Moore, J.; Nicholson, S.; Moore, J. G.

1985-01-01

Research at NASA Lewis Research Center gave the opportunity to incorporate new control volumes in the Denton 3-D finite-volume time marching code. For duct flows, the new control volumes require no transverse smoothing and this allows calculations with large transverse gradients in properties without significant numerical total pressure losses. Possibilities for improving the Denton code to obtain better distributions of properties through shocks were demonstrated. Much better total pressure distributions through shocks are obtained when the interpolated effective pressure, needed to stabilize the solution procedure, is used to calculate the total pressure. This simple change largely eliminates the undershoot in total pressure down-stream of a shock. Overshoots and undershoots in total pressure can then be further reduced by a factor of 10 by adopting the effective density method, rather than the effective pressure method. Use of a Mach number dependent interpolation scheme for pressure then removes the overshoot in static pressure downstream of a shock. The stability of interpolation schemes used for the calculation of effective density is analyzed and a Mach number dependent scheme is developed, combining the advantages of the correct perfect gas equation for subsonic flow with the stability of 2-point and 3-point interpolation schemes for supersonic flow.

Fate of a mutation in a fluctuating environment

PubMed Central

Cvijović, Ivana; Good, Benjamin H.; Jerison, Elizabeth R.; Desai, Michael M.

2015-01-01

Natural environments are never truly constant, but the evolutionary implications of temporally varying selection pressures remain poorly understood. Here we investigate how the fate of a new mutation in a fluctuating environment depends on the dynamics of environmental variation and on the selective pressures in each condition. We find that even when a mutation experiences many environmental epochs before fixing or going extinct, its fate is not necessarily determined by its time-averaged selective effect. Instead, environmental variability reduces the efficiency of selection across a broad parameter regime, rendering selection unable to distinguish between mutations that are substantially beneficial and substantially deleterious on average. Temporal fluctuations can also dramatically increase fixation probabilities, often making the details of these fluctuations more important than the average selection pressures acting on each new mutation. For example, mutations that result in a trade-off between conditions but are strongly deleterious on average can nevertheless be more likely to fix than mutations that are always neutral or beneficial. These effects can have important implications for patterns of molecular evolution in variable environments, and they suggest that it may often be difficult for populations to maintain specialist traits, even when their loss leads to a decline in time-averaged fitness. PMID:26305937

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorshkov, V.G.; Makarieva, A.M.

The oceanic phytoplancton productivity may essentially influence the total rate of the atmospheric CO{sub 2} absorption by the ocean - that is, a considerable amount of CO{sub 2} will be taken-up in the 50 micrometers thick layer near the air-sea interface. Even if phytoplancton production constitutes only 5% of the total oceanic biota production, this will increase the rate of CO{sub 2} absorption more than twice compared with the present estimates. The reason is that metabolic activity of phytoplancton leads to the emergence in a thin scin (50 micrometers, the average size of phytoplancton cells) layer near the water surfacemore » of an additional minimum in the CO{sub 2} partial pressure profile and of an additional maximum of {Delta} {sup 13}C in the same area. These two extremums cannot be detected if the corresponding characteristics are averaged over any microscopic area in the well mixing layer that is more than 1 meter deep, which is usually the case when the oceanic concentrations of CO{sub 2} are measured. This effect may account for the observed contradiction between the existing estimates of the rate of CO{sub 2} absorption, that are based either on measuring gradient of the concentrations of the dissolved organic and inorganic carbon or on measuring of the physical flux of CO{sub 2} through the air-sea interface.« less

Analysis of a Shock-Associated Noise Prediction Model Using Measured Jet Far-Field Noise Data

NASA Technical Reports Server (NTRS)

Dahl, Milo D.; Sharpe, Jacob A.

2014-01-01

A code for predicting supersonic jet broadband shock-associated noise was assessed us- ing a database containing noise measurements of a jet issuing from a convergent nozzle. The jet was operated at 24 conditions covering six fully expanded Mach numbers with four total temperature ratios. To enable comparisons of the predicted shock-associated noise component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise component spectra. Comparisons between predicted and measured shock-associated noise component spectra were used to identify de ciencies in the prediction model. Proposed revisions to the model, based on a study of the overall sound pressure levels for the shock-associated noise component of the mea- sured data, a sensitivity analysis of the model parameters with emphasis on the de nition of the convection velocity parameter, and a least-squares t of the predicted to the mea- sured shock-associated noise component spectra, resulted in a new de nition for the source strength spectrum in the model. An error analysis showed that the average error in the predicted spectra was reduced by as much as 3.5 dB for the revised model relative to the average error for the original model.

Clinical Experience with the M4 Ahmed Glaucoma Drainage Implant.

PubMed

Sluch, Ilya; Gudgel, Brett; Dvorak, Justin; Anne Ahluwalia, Mary; Ding, Kai; Vold, Steve; Sarkisian, Steven

2017-01-01

To evaluate the safety and efficacy of the M4 (porous polyethylene plate) Ahmed Glaucoma Valve (AGV) drainage implant in a multicenter retrospective study. A retrospective chart review of medical records of patients who had undergone the M4 Ahmed valve was performed from January 2013 to April 2015. The primary outcome measure was surgical failure defined as: Less than a 20% reduction in baseline intraocular pressure (IOP) to last follow-up visit, final IOP less than 5 mm Hg or greater than 18 mm Hg, reoperation for glaucoma, or loss of light perception vision. All eyes not meeting the above criteria were defined as success. A total of 291 eyes met all study inclusion criteria. The average follow-up in the study was 6 months (±7.6 months) with 112 patients achieving 12-month follow-up (38.5%). 208 eyes (71.5%) met the study success criteria at final follow-up. No statistically significant spikes in postoperative IOP at 1 and 4 months were detected. The average preoperative IOP was 26.0 on an average of 2.8 medications. At 6 months, the average IOP dropped to 16.7 on 0.9 medications and stayed relatively stable at 15.8 on 1.2 medications at 12-month follow-up. The M4 valve appears to have less of a hypertensive phase compared with the other Ahmed class valves with a similar safety profile. While 71.5% success rate was achieved at final follow-up, the failure rate steadily increased over time. While the M4 production has been discontinued, the porous design of the M4 may avoid a pressure spike in the Ahmed valve class and warrants future investigation for valve design. How to cite this article: Sluch I, Gudgel B, Dvorak J, Ahluwalia MA, Ding K, Vold S, Sarkisian S. Clinical Experience with the M4 Ahmed Glaucoma Drainage Implant. J Curr Glaucoma Pract 2017;11(3):92-96.

A Total Ozone Dependent Ozone Profile Climatology Based on Ozone-Sondes and Aura MLS Data

NASA Astrophysics Data System (ADS)

Labow, G. J.; McPeters, R. D.; Ziemke, J. R.

2014-12-01

A new total ozone-based ozone profile climatology has been created for use in satellite and/or ground based ozone retrievals. This climatology was formed by combining data from the Microwave Limb Sounder (MLS) with data from balloon sondes and binned by zone and total ozone. Because profile shape varies with total column ozone, this climatology better captures the ozone variations than the previously used seasonal climatologies, especially near the tropopause. This is significantly different than ozone climatologies used in the past as there is no time component. The MLS instrument on Aura has excellent latitude coverage and measures ozone profiles daily from the upper troposphere to the lower mesosphere at ~3.5 km resolution. Almost a million individual MLS ozone measurements are merged with data from over 55,000 ozonesondes which are then binned as a function of total ozone. The climatology consists of average ozone profiles as a function of total ozone for six 30 degree latitude bands covering altitudes from 0-75 km (in Z* pressure altitude coordinates). This new climatology better represents the profile shape as a function of total ozone than previous climatologies and shows some remarkable and somewhat unexpected correlations between total ozone and ozone in the lower altitudes, particularly in the lower and middle troposphere. These data can also be used to infer biases and errors in either the MLS retrievals or ozone sondes.

Effect of peroral esophageal myotomy for achalasia treatment: A Chinese study

PubMed Central

Lu, Bin; Li, Meng; Hu, Yue; Xu, Yi; Zhang, Shuo; Cai, Li-Jun

2015-01-01

AIM: To assess the safety and feasibility of peroral esophageal myotomy (POEM) in patients with achalasia. METHODS: From January 2012 to March 2014, 50 patients (28 men, 22 women; mean age: 42.8 years, range: 14-70 years) underwent POEM. Pre- and postoperative symptoms were quantified using the Eckardt scoring system. Barium swallow and esophagogastroscopy were performed before and after POEM, respectively. Esophageal motility was evaluated in all patients, both preoperatively and one month after POEM treatment, using a high-resolution manometry system. Manometry data, Eckardt scores, lower esophageal sphincter pressure and barium swallow results were used to evaluate the effect of the procedure. RESULTS: POEM was successfully completed for all patients. The mean procedure time was 55.4 ± 17.3 min and the mean total length of myotomy of the circular esophagus was 10.5 ± 2.6 cm. No specific complications occurred, with the exception of two patients that developed asymptomatic pneumomediastinum and subcutaneous emphysema. Clinical improvement in symptoms was achieved in all patients. Approximately 77.5% of patients experienced weight gain 6 mo after POEM, with an average of 4.78 kg (range: 2-15 kg). The lower esophageal sphincter resting pressure, four second integrated relaxation pressure and Eckardt scores were all significantly reduced after POEM (Ps < 0.05). A small segment of proximal esophageal peristalsis appeared postoperatively in two patients, but without normal esophageal peristalsis. The average diameter of the esophageal lumen decreased significantly from 4.39 to 3.09 cm (P < 0.01). CONCLUSION: POEM can relieve achalasia symptoms, improve gastroesophageal junction relaxation and restore esophageal body motility function, but not normal esophageal peristalsis. PMID:25987787

Estimating the Instantaneous Drag-Wind Relationship for a Horizontally Homogeneous Canopy

NASA Astrophysics Data System (ADS)

Pan, Ying; Chamecki, Marcelo; Nepf, Heidi M.

2016-07-01

The mean drag-wind relationship is usually investigated assuming that field data are representative of spatially-averaged metrics of statistically stationary flow within and above a horizontally homogeneous canopy. Even if these conditions are satisfied, large-eddy simulation (LES) data suggest two major issues in the analysis of observational data. Firstly, the streamwise mean pressure gradient is usually neglected in the analysis of data from terrestrial canopies, which compromises the estimates of mean canopy drag and provides misleading information for the dependence of local mean drag coefficients on local velocity scales. Secondly, no standard approach has been proposed to investigate the instantaneous drag-wind relationship, a critical component of canopy representation in LES. Here, a practical approach is proposed to fit the streamwise mean pressure gradient using observed profiles of the mean vertical momentum flux within the canopy. Inclusion of the fitted mean pressure gradient enables reliable estimates of the mean drag-wind relationship. LES data show that a local mean drag coefficient that characterizes the relationship between mean canopy drag and the velocity scale associated with total kinetic energy can be used to identify the dependence of the local instantaneous drag coefficient on instantaneous velocity. Iterative approaches are proposed to fit specific models of velocity-dependent instantaneous drag coefficients that represent the effects of viscous drag and the reconfiguration of flexible canopy elements. LES data are used to verify the assumptions and algorithms employed by these new approaches. The relationship between mean canopy drag and mean velocity, which is needed in models based on the Reynolds-averaged Navier-Stokes equations, is parametrized to account for both the dependence on velocity and the contribution from velocity variances. Finally, velocity-dependent drag coefficients lead to significant variations of the calculated displacement height and roughness length with wind speed.

Laparoscopic prototype for optical sealing of renal blood vessels

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Hutchens, Thomas C.; Larson, Eric R.; Gonzalez, David A.; Chang, Chun-Hung; Nau, William H.; Fried, Nathaniel M.

2017-02-01

Energy-based, radiofrequency and ultrasonic devices provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternative for vessel sealing with less collateral thermal damage. Previous studies demonstrated vessel sealing in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices in surgical use was developed, and tests were conducted on porcine renal blood vessels. The 5-mm-OD prototype featured a traditional Maryland jaw configuration. Laser energy was delivered through a 550-μm-core fiber and side-delivery from the lower jaw, with beam dimensions of 18-mm-length x 1.2-mm-width. The 1470-nm diode laser delivered 68 W with 3 s activation time. A total of 69 porcine renal vessels with mean diameter of 3.3 +/- 1.7 mm were tested, ex vivo. Vessels smaller than 5 mm were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038 +/- 474 mmHg. Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174 +/- 221 mmHg. Seal width, thermal damage zone, and thermal spread averaged 1.7 +/- 0.8, 3.4 +/- 0.7, and 1.0 +/- 0.4 mm. A novel optical laparoscopic prototype with 5-mm- OD shaft integrated within a standard Maryland jaw design consistently sealed vessels less than 5 mm with minimal thermal spread. Further in vivo studies are planned to test performance across a variety of vessels and tissues.

Microsecond simulations of the folding/unfolding thermodynamics of the Trp-cage mini protein

PubMed Central

Day, Ryan; Paschek, Dietmar; Garcia, Angel E.

2012-01-01

We study the unbiased folding/unfolding thermodynamics of the Trp-cage miniprotein using detailed molecular dynamics simulations of an all-atom model of the protein in explicit solvent, using the Amberff99SB force field. Replica-exchange molecular dynamics (REMD) simulations are used to sample the protein ensembles over a broad range of temperatures covering the folded and unfolded states, and at two densities. The obtained ensembles are shown to reach equilibrium in the 1 μs per replica timescale. The total simulation time employed in the calculations exceeds 100 μs. Ensemble averages of the fraction folded, pressure, and energy differences between the folded and unfolded states as a function of temperature are used to model the free energy of the folding transition, ΔG(P,T), over the whole region of temperature and pressures sampled in the simulations. The ΔG(P,T) diagram describes an ellipse over the range of temperatures and pressures sampled, predicting that the system can undergo pressure induced unfolding and cold denaturation at low temperatures and high pressures, and unfolding at low pressures and high temperatures. The calculated free energy function exhibits remarkably good agreement with the experimental folding transition temperature (Tf = 321 K), free energy and specific heat changes. However, changes in enthalpy and entropy are significantly different than the experimental values. We speculate that these differences may be due to the simplicity of the semi-empirical force field used in the simulations and that more elaborate force fields may be required to describe appropriately the thermodynamics of proteins. PMID:20408169

Measurement of mean circulatory filling pressure and vascular compliance in domestic pigs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D; Tenaschuk, B

1990-06-01

To measure mean circulatory filling pressure (Pmcf), a balloon was placed in the right atrium of seven pentobarbital sodium-anesthetized open-chest pigs for transient occlusion of flow combined with mechanical transfer of blood from the arterial to the venous circulation. Equilibration occurred within 6-8 s at a pressure at 12.3 +/- 0.3 (SE) mmHg after a 2.9 +/- 0.2 ml/kg transfer of blood. In another group of pentobarbital sodium-anesthetized closed-chest pigs, acetylcholine (ACh) was used to induce cardiac arrest. The Pmcf was 11.6 +/- 1.0 mmHg in the 7:17 pigs that arrested for 6-8 s. In four isoflurane-anesthetized closed-chest pigs, the Pmcf was 12.0 +/- 1.0 mmHg after terminal cardiac arrest induced by KCl. The pressure gradient for venous return [Pmcf--right atrial pressure (Pra)] averaged 5.9 +/- 0.2 mmHg. Total vascular compliance estimated from plots of Pmcf at base line, 5, and 10 ml/kg increases in circulating volume was 2.1 +/- 0.3 and 3.5 +/- 0.9 ml.kg-1.mmHg-1 in the balloon and ACh groups, respectively compared with 2.8 +/- 0.4 ml.kg-1.mmHg-1 using a volume infusion-withdrawal method without circulatory arrest. The use of ACh for the estimate of Pmcf in the pig is not recommended because of failure to consistently induce circulatory arrest and probable failure to achieve sufficient equilibrium of vascular pressures 6-8 s postarrest when it occurs.

Comparison of 808, 980, and 1075nm lasers for noninvasive thermal coagulation of the canine vas deferens, ex vivo

NASA Astrophysics Data System (ADS)

Cilip, Christopher M.; Schweinsberger, Gino R.; Fried, Nathaniel M.

2011-03-01

Successful noninvasive laser coagulation of the canine vas deferens, in vivo, has been previously reported. However, the therapeutic window for treatment is relatively narrow. This study determines the dependence of vas thermal coagulation on laser wavelength for development of a noninvasive laser vasectomy procedure. Noninvasive laser coagulation of canine vas tissue, ex vivo, was performed using three commonly available near-infrared laser wavelengths: 808, 980, and 1075 nm. Each laser delivered an average power of 9.2 W, 500-ms pulse duration, pulse rate of 1.0-Hz, and 3.2-mm diameter laser spot, synchronized with cryogen spray cooling of the scrotal skin surface for a total treatment time of 60 s. Vas burst pressures were measured to determine strength of vas closure and compared to previously reported ejaculation pressures. Gross inspection of vas and scrotal skin was also performed immediately after the procedure as an indicator of thermal coagulation and skin burns. The 1075 nm laser produced the highest vas burst pressures (288 +/- 28 mmHg), significantly greater than previously reported ejaculation pressures (136 +/- 29 mmHg). The 808 nm wavelength produced insufficient vas burst pressures of 141 +/- 61 mmHg, and minor scrotal skin burns were observed in at least one case. The 980 nm wavelength was unable to produce thermal coagulation of the vas, with low burst pressures (89 +/- 58 mmHg) and severe scrotal skin burns. The 1075 nm wavelength was the only near-IR wavelength that consistently thermally coagulated the vas with a strong degree of closure and without any scrotal skin burns.

Effect of bolus volume and viscosity on pharyngeal automated impedance manometry variables derived for broad Dysphagia patients.

PubMed

Omari, Taher I; Dejaeger, Eddy; Tack, Jan; Van Beckevoort, Dirk; Rommel, Nathalie

2013-06-01

Automated impedance manometry (AIM) analysis measures swallow variables defining bolus timing, pressure, contractile vigour, and bolus presence, which are combined to derive a swallow risk index (SRI) correlating with aspiration. In a heterogeneous cohort of dysphagia patients, we assessed the impact of bolus volume and viscosity on AIM variables. We studied 40 patients (average age = 46 years). Swallowing of boluses was recorded with manometry, impedance, and videofluoroscopy. AIMplot software was used to derive functional variables: peak pressure (PeakP), pressure at nadir impedance (PNadImp), time from nadir impedance to peak pressure (TNadImp-PeakP), the interval of impedance drop in the distal pharynx (flow interval, FI), upper oesophageal sphincter (UES) relaxation interval (UES RI), nadir UES pressure (Nad UESP), UES intrabolus pressure (UES IBP), and UES resistance. The SRI was derived using the formula SRI = (FI * PNadImp)/(PeakP * (TNadImp-PeakP + 1)) * 100. A total of 173 liquid, 44 semisolid, and 33 solid boluses were analysed. The SRI was elevated in relation to aspiration. PeakP increased with volume. SRI was not significantly altered by bolus volume. PNadImp, UES IBP, and UES resistance increased with viscosity. SRI was lower with increased viscosity. In patients with dysphagia, the SRI is elevated in relation to aspiration, reduced by bolus viscosity, and not affected by bolus volume. These data provide evidence that pharyngeal AIM analysis may have clinical utility for assessing deglutitive aspiration risk to liquid boluses.

The Combined Effects of Aircraft and Road Traffic Noise and Aircraft and Railway Noise on Noise Annoyance-An Analysis in the Context of the Joint Research Initiative NORAH.

PubMed

Wothge, Jördis; Belke, Christin; Möhler, Ulrich; Guski, Rainer; Schreckenberg, Dirk

2017-08-02

The Noise Related Annoyance Cognition and Health (NORAH) research initiative is one of the most extensive studies on the physiological and psychological long-term effects of transportation noise in Europe. It includes research on the quality of life and annoyance as well as cardiovascular effects, sleep disturbance, breast cancer, blood pressure, depression and the cognitive development of children. Within the realm of the annoyance module of the study approximately 10,000 residents of the Rhine-Main district were surveyed on the combined effects of transportation noise. This included combined noise from aircraft and road traffic noise ( N = 4905), or aircraft and railway noise ( N = 4777). Results show that judgment of the total noise annoyance of participants was strongly determined by the sound source which was judged as more annoying (in this case aircraft noise). To a lesser extent, the average sound pressure level of the two present sources was also of relevance.

The Combined Effects of Aircraft and Road Traffic Noise and Aircraft and Railway Noise on Noise Annoyance—An Analysis in the Context of the Joint Research Initiative NORAH

PubMed Central

Wothge, Jördis; Belke, Christin; Möhler, Ulrich; Guski, Rainer; Schreckenberg, Dirk

2017-01-01

The Noise Related Annoyance Cognition and Health (NORAH) research initiative is one of the most extensive studies on the physiological and psychological long-term effects of transportation noise in Europe. It includes research on the quality of life and annoyance as well as cardiovascular effects, sleep disturbance, breast cancer, blood pressure, depression and the cognitive development of children. Within the realm of the annoyance module of the study approximately 10,000 residents of the Rhine-Main district were surveyed on the combined effects of transportation noise. This included combined noise from aircraft and road traffic noise (N = 4905), or aircraft and railway noise (N = 4777). Results show that judgment of the total noise annoyance of participants was strongly determined by the sound source which was judged as more annoying (in this case aircraft noise). To a lesser extent, the average sound pressure level of the two present sources was also of relevance. PMID:28767095

Specialized physiological studies in support of manned space flight

NASA Technical Reports Server (NTRS)

Luft, U. C.

1976-01-01

Subjects were tested for tolerance to lower body negative pressure (LBNP) before and after acute dehydration by working intermittenly for two hours without fluid replacement. On the second day there-after the LBNP tests were repeated before and after acute dehydration. The LBNP test consisted of 5 min long consective stages at -20, -30, -40, -50 and -60 Torr. Tests were terminated when syncope was imminent or the full sequence was completed. Tolerance was expressed in terms of cumulative stress in Torr x min. Measurements of body mass, density, fat fraction and total body water (TBW) were made before and after acclimation. Blood volume and its constituents were determined before and after each of the four LBNP tests. During LBNP, heart rate, blood pressure, and changes in calf and forearm volume were recorded every minute. Results showed: acute dehydration caused a significant loss in average LBNP tolerance on all subjects. Acclimation to heat did not significantly affect LBNP tolerance in hydrated subjects but significantly improved it on dehydrated subjects.

S-Duct Engine Inlet Flow Control Using SDBD Plasma Streamwise Vortex Generators

NASA Astrophysics Data System (ADS)

Kelley, Christopher; He, Chuan; Corke, Thomas

2009-11-01

The results of a numerical simulation and experiment characterizing the performance of plasma streamwise vortex generators in controlling separation and secondary flow within a serpentine, diffusing duct are presented. A no flow control case is first run to check agreement of location of separation, development of secondary flow, and total pressure recovery between the experiment and numerical results. Upon validation, passive vane-type vortex generators and plasma streamwise vortex generators are implemented to increase total pressure recovery and reduce flow distortion at the aerodynamic interface plane: the exit of the S-duct. Total pressure recovery is found experimentally with a pitot probe rake assembly at the aerodynamic interface plane. Stagnation pressure distortion descriptors are also presented to show the performance increase with plasma streamwise vortex generators in comparison to the baseline no flow control case. These performance parameters show that streamwise plasma vortex generators are an effective alternative to vane-type vortex generators in total pressure recovery and total pressure distortion reduction in S-duct inlets.

Effect of organic-matter type and thermal maturity on methane adsorption in shale-gas systems

USGS Publications Warehouse

Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Yang, Rongsheng

2012-01-01

A series of methane (CH4) adsorption experiments on bulk organic rich shales and their isolated kerogens were conducted at 35 °C, 50 °C and 65 °C and CH4 pressure of up to 15 MPa under dry conditions. Samples from the Eocene Green River Formation, Devonian–Mississippian Woodford Shale and Upper Cretaceous Cameo coal were studied to examine how differences in organic matter type affect natural gas adsorption. Vitrinite reflectance values of these samples ranged from 0.56–0.58 %Ro. In addition, thermal maturity effects were determined on three Mississippian Barnett Shale samples with measured vitrinite reflectance values of 0.58, 0.81 and 2.01 %Ro. For all bulk and isolated kerogen samples, the total amount of methane adsorbed was directly proportional to the total organic carbon (TOC) content of the sample and the average maximum amount of gas sorption was 1.36 mmol of methane per gram of TOC. These results indicate that sorption on organic matter plays a critical role in shale-gas storage. Under the experimental conditions, differences in thermal maturity showed no significant effect on the total amount of gas sorbed. Experimental sorption isotherms could be fitted with good accuracy by the Langmuir function by adjusting the Langmuir pressure (PL) and maximum sorption capacity (Γmax). The lowest maturity sample (%Ro = 0.56) displayed a Langmuir pressure (PL) of 5.15 MPa, significantly larger than the 2.33 MPa observed for the highest maturity (%Ro > 2.01) sample at 50 °C. The value of the Langmuir pressure (PL) changes with kerogen type in the following sequence: type I > type II > type III. The thermodynamic parameters of CH4 adsorption on organic rich shales were determined based on the experimental CH4 isotherms. For the adsorption of CH4 on organic rich shales and their isolated kerogen, the heat of adsorption (q) and the standard entropy (Δs0) range from 7.3–28.0 kJ/mol and from −36.2 to −92.2 J/mol/K, respectively.

78 FR 19262 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

... FEDERAL HOUSING FINANCE AGENCY [No. 2013-N-04] Notice of Annual Adjustment of the Cap on Average.... ACTION: Notice. SUMMARY: The Federal Housing Finance Agency (FHFA) has adjusted the cap on average total... Federal Deposit Insurance Corporation and that has average total assets below a statutory cap.\\2\\ The Bank...

75 FR 9601 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-03

... FEDERAL HOUSING FINANCE AGENCY [No. 2010-N-01] Notice of Annual Adjustment of the Cap on Average.... ACTION: Notice. SUMMARY: The Federal Housing Finance Agency (FHFA) has adjusted the cap on average total... Deposit Insurance Corporation and that has average total assets below a statutory cap. See 12 U.S.C. 1422...

Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

PubMed

Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

2017-05-01

Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Exercise-induced Pulmonary Hypertension

PubMed Central

Vanderpool, Rebecca; Dhakal, Bishnu P.; Saggar, Rajeev; Saggar, Rajan; Vachiery, Jean-Luc; Lewis, Gregory D.

2013-01-01

Exercise stresses the pulmonary circulation through increases in cardiac output (Q.) and left atrial pressure. Invasive as well as noninvasive studies in healthy volunteers show that the slope of mean pulmonary artery pressure (mPAP)–flow relationships ranges from 0.5 to 3 mm Hg⋅min⋅L−1. The upper limit of normal mPAP at exercise thus approximates 30 mm Hg at a Q. of less than 10 L⋅min−1 or a total pulmonary vascular resistance at exercise of less than 3 Wood units. Left atrial pressure increases at exercise with an average upstream transmission to PAP in a close to one-for-one mm Hg fashion. Multipoint PAP–flow relationships are usually described by a linear approximation, but present with a slight curvilinearity, which is explained by resistive vessel distensibility. When mPAP is expressed as a function of oxygen uptake or workload, plateau patterns may be observed in patients with systolic heart failure who cannot further increase Q. at the highest levels of exercise. Exercise has to be dynamic to avoid the increase in systemic vascular resistance and abrupt changes in intrathoracic pressure that occur with resistive exercise and can lead to unpredictable effects on the pulmonary circulation. Postexercise measurements are unreliable because of the rapid return of pulmonary vascular pressures and flows to the baseline resting state. Recent studies suggest that exercise-induced increase in PAP to a mean higher than 30 mm Hg may be associated with dyspnea-fatigue symptomatology. PMID:23348976

Motion at the Tibial and Polyethylene Component Interface in a Mobile-Bearing Total Ankle Replacement.

PubMed

Lundeen, Gregory A; Clanton, Thomas O; Dunaway, Linda J; Lu, Minggen

2016-08-01

Normal biomechanics of the ankle joint includes sagittal as well as axial rotation. Current understanding of mobile-bearing motion at the tibial-polyethylene interface in total ankle arthroplasty (TAA) is limited to anterior-posterior (AP) motion of the polyethylene component. The purpose of our study was to define the motion of the polyethylene component in relation to the tibial component in a mobile-bearing TAA in both the sagittal and axial planes in postoperative patients. Patients who were a minimum of 12 months postoperative from a third-generation mobile-bearing TAA were identified. AP images were saved at maximum internal and external rotation, and the lateral images were saved in maximum plantarflexion and dorsiflexion. Sagittal range of motion and AP translation of the polyethylene component were measured from the lateral images. Axial rotation was determined by measuring the relative position of the 2 wires within the polyethylene component on AP internal and external rotation imaging. This relationship was compared to a table developed from fluoroscopic images taken at standardized degrees of axial rotation of a nonimplanted polyethylene with the associated length relationship of the 2 imbedded wires. Sixteen patients were included in this investigation, 9 (56%) were male and average age was 68 (range, 49-80) years. Time from surgery averaged 25 (range, 12-38) months. Total sagittal range of motion averaged 23±9 (range, 9-33) degrees. Axial motion for total internal and external rotation of the polyethylene component on the tibial component averaged 6±5 (range, 0-18) degrees. AP translation of the polyethylene component relative to the tibial component averaged 1±1 (range, 0-3) mm. There was no relationship between axial rotation or AP translation of the polyethylene component and ankle joint range of motion (P > .05). To our knowledge, this is the first investigation to measure axial and sagittal motion of the polyethylene component at the tibial implant interface in patients following a mobile-bearing TAA. Based on outcome scores and range-of-motion measurements, we believe the patients in this study are a representative cross section of subjects compared to other TAA research results. The results from this investigation indicate the potential for a mobile-bearing TAA to fall within the parameters of normal polyaxial ankle motion. The multiplanar articulation in a mobile-bearing TAA may reduce excessively high peak pressures during the complex dynamic tibial and talar motion, which may have a positive influence on gait pattern, polyethylene wear, and implant longevity. Level IV, case series. © The Author(s) 2016.

Blood Pressure Changes in Relation to Arsenic Exposure in a U.S. Pregnancy Cohort

PubMed Central

Farzan, Shohreh F.; Chen, Yu; Wu, Fen; Jiang, Jieying; Liu, Mengling; Baker, Emily; Korrick, Susan A.

2015-01-01

Background Inorganic arsenic exposure has been related to the risk of increased blood pressure based largely on cross-sectional studies conducted in highly exposed populations. Pregnancy is a period of particular vulnerability to environmental insults. However, little is known about the cardiovascular impacts of arsenic exposure during pregnancy. Objectives We evaluated the association between prenatal arsenic exposure and maternal blood pressure over the course of pregnancy in a U.S. population. Methods The New Hampshire Birth Cohort Study is an ongoing prospective cohort study in which > 10% of participant household wells exceed the arsenic maximum contaminant level of 10 μg/L established by the U.S. EPA. Total urinary arsenic measured at 24–28 weeks gestation was measured and used as a biomarker of exposure during pregnancy in 514 pregnant women, 18–45 years of age, who used a private well in their household. Outcomes were repeated blood pressure measurements (systolic, diastolic, and pulse pressure) recorded during pregnancy. Results Using linear mixed effects models, we estimated that, on average, each 5-μg/L increase in urinary arsenic was associated with a 0.15-mmHg (95% CI: 0.02, 0.29; p = 0.022) increase in systolic blood pressure per month and a 0.14-mmHg (95% CI: 0.02, 0.25; p = 0.021) increase in pulse pressure per month over the course of pregnancy. Conclusions In our U.S. cohort of pregnant women, arsenic exposure was associated with greater increases in blood pressure over the course of pregnancy. These findings may have important implications because even modest increases in blood pressure impact cardiovascular disease risk. Citation Farzan SF, Chen Y, Wu F, Jiang J, Liu M, Baker E, Korrick SA, Karagas MR. 2015. Blood pressure changes in relation to arsenic exposure in a U.S. pregnancy cohort. Environ Health Perspect 123:999–1006; http://dx.doi.org/10.1289/ehp.1408472 PMID:25793356

Are labour-intensive efforts to prevent pressure ulcers cost-effective?

PubMed

Mathiesen, Anne Sofie Mølbak; Nørgaard, Kamilla; Andersen, Marie Frederikke Bruun; Møller, Klaus Meyer; Ehlers, Lars Holger

2013-10-01

Pressure ulcers are a major problem in Danish healthcare with a prevalence of 13-43% among hospitalized patients. The associated costs to the Danish Health Care Sector are estimated to be €174.5 million annually. In 2010, The Danish Society for Patient Safety introduced the Pressure Ulcer Bundle (PUB) in order to reduce hospital-acquired pressure ulcers by a minimum of 50% in five hospitals. The PUB consists of evidence-based preventive initiatives implemented by ward staff using the Model for Improvement. To investigate the cost-effectiveness of labour-intensive efforts to reduce pressure ulcers in the Danish Health Care Sector, comparing the PUB with standard care. A decision analytic model was constructed to assess the costs and consequences of hospital-acquired pressure ulcers during an average hospital admission in Denmark. The model inputs were based on a systematic review of clinical efficacy data combined with local cost and effectiveness data from the Thy-Mors Hospital, Denmark. A probabilistic sensitivity analysis (PSA) was conducted to assess the uncertainty. Prevention of hospital-acquired pressure ulcers by implementing labour-intensive effects according to the PUB was cost-saving and resulted in an improved effect compared to standard care. The incremental cost of the PUB was -€38.62. The incremental effects were a reduction of 9.3% prevented pressure ulcers and 0.47% prevented deaths. The PSAs confirmed the incremental cost-effectiveness ratio (ICER)'s dominance for both prevented pressure ulcers and saved lives with the PUB. This study shows that labour-intensive efforts to reduce pressure ulcers on hospital wards can be cost-effective and lead to savings in total costs of hospital and social care. The data included in the study regarding costs and effects of the PUB in Denmark were based on preliminary findings from a pilot study at Thy-Mors Hospital and literature.

Gasdynamic Inlet Isolation in Rotating Detonation Engine

DTIC Science & Technology

2010-12-01

2D Total Variation Diminishing (TVD): Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Total Variation Diminishing (TVD) limiter: Continuous Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate...Continuous 94 Riemann Solver Minimum Dissipation: LHS & RHS Activate pressure switch : Supersonic Activate pressure gradient switch: Normal

The XMM Cluster Outskirts Project (X-COP): Thermodynamic properties of the intracluster medium out to R200 in Abell 2319

NASA Astrophysics Data System (ADS)

Ghirardini, V.; Ettori, S.; Eckert, D.; Molendi, S.; Gastaldello, F.; Pointecouteau, E.; Hurier, G.; Bourdin, H.

2018-06-01

Aims: We present the joint analysis of the X-ray and Sunyaev-Zel'dovich (SZ) signals in Abell 2319, the galaxy cluster with the highest signal-to-noise ratio in SZ Planck maps and that has been surveyed within our XMM-Newton Cluster Outskirts Project (X-COP), a very large program which aims to grasp the physical condition in 12 local (z < 0.1) and massive (M200 > 3 × 1014 M⊙) galaxy clusters out to R200 and beyond. Methods: We recover the profiles of the thermodynamic properties by the geometrical deprojection of the X-ray surface brightness, of the SZ Comptonization parameter, and accurate and robust spectroscopic measurements of the gas temperature out to 3.2 Mpc (1.6 R200), 4 Mpc (2 R200), and 1.6 Mpc (0.8 R200), respectively. We resolve the clumpiness of the gas density to be below 20% over the entire observed volume. We also demonstrate that most of this clumpiness originates from the ongoing merger and can be associated with large-scale inhomogeneities (the "residual" clumpiness). We estimate the total mass through the hydrostatic equilibrium equation. This analysis is done both in azimuthally averaged radial bins and in eight independent angular sectors, enabling us to study in detail the azimuthal variance of the recovered properties. Results: Given the exquisite quality of the X-ray and SZ datasets, their radial extension, and their complementarity, we constrain at R200 the total hydrostatic mass, modelled with a Navarro-Frenk-White profile at very high precision (M200 = 10.7 ± 0.5stat. ± 0.9syst. × 1014 M⊙). We identify the ongoing merger and how it is affecting differently the gas properties in the resolved azimuthal sectors. We have several indications that the merger has injected a high level of non-thermal pressure in this system: the clumping free density profile is above the average profile obtained by stacking Rosat/PSPC observations; the gas mass fraction recovered using our hydrostatic mass profile exceeds the expected cosmic gas fraction beyond R500; the pressure profile is flatter than the fit obtained by the Planck Collaboration; the entropy profile is flatter than the mean profile predicted from non-radiative simulations; the analysis in azimuthal sectors has revealed that these deviations occur in a preferred region of the cluster. All these tensions are resolved by requiring a relative support of about 40% from non-thermal to the total pressure at R200.

Relation of raw and cooked vegetable consumption to blood pressure: the INTERMAP Study

PubMed Central

Chan, Q; Stamler, J; Brown, I J; Daviglus, M L; Van Horn, L; Dyer, A R; Oude Griep, L M; Miura, K; Ueshima, H; Zhao, L; Nicholson, J K; Holmes, E; Elliott, P

2014-01-01

Inverse associations have been reported of overall vegetable intake to blood pressure (BP); whether such relations prevail for both raw and cooked vegetables has not been examined. Here we report cross-sectional associations of vegetable intakes with BP for 2195 Americans ages 40–59 in the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP) using four standardized multi-pass 24-h dietary recalls and eight BP measurements. Relations to BP of raw and cooked vegetables consumption, and main individual constituents were assessed by multiple linear regression. Intakes of both total raw and total cooked vegetables considered separately were inversely related to BP in multivariate-adjusted models. Estimated average systolic BP differences associated with two s.d. differences in raw vegetable intake (68 g per 1000 kcal) and cooked vegetable intake (92 g per 1000 kcal) were −1.9 mm Hg (95% confidence interval (CI): −3.1, −0.8; P=0.001) and −1.3 mm Hg (95% CI: −2.5, −0.2; P=0.03) without body mass index (BMI) in the full model; −1.3 mm Hg (95% CI: −2.4, −0.2; P=0.02) and −0.9 mm Hg (95% CI: −2.0, 0.2; P=0.1) with additional adjustment for BMI. Among commonly consumed individual raw vegetables, tomatoes, carrots, and scallions related significantly inversely to BP. Among commonly eaten cooked vegetables, tomatoes, peas, celery, and scallions related significantly inversely to BP. PMID:24257514

High pressure jet injection of viscous solutions for endoscopic submucosal dissection (ESD): first clinical experience.

PubMed

Pioche, Mathieu; Lépilliez, Vincent; Déprez, Pierre; Giovannini, Marc; Caillol, Fabrice; Piessevaux, Hubert; Rivory, Jérôme; Guillaud, Olivier; Ciocîrlan, Mihai; Salmon, Damien; Lienhart, Isabelle; Lafon, Cyril; Saurin, Jean-Christophe; Ponchon, Thierry

2015-08-01

Long lasting elevation is a key factor during endoscopic submucosal dissection (ESD) and can be obtained by water jet injection of saline solution or by viscous macromolecular solutions. In a previous animal study, we assessed the Nestis Enki II system to combine jet injection and viscous solutions. In the present work, we used this combination in humans in different sites of the digestive tract. We retrospectively report all of the consecutive ESD procedures performed with jet injection of viscous solutions in four centers. Information was collected about the lesion, the procedure, the histological result, and the outcomes for the patient. In total, 45 resections were completed by six operators: five experts and one beginner with only one previous experience in human ESD. Lesions were located in the esophagus (10), the stomach (11), the duodenum (1), the colon (1) and the rectum (22). Average maximal lesion diameter was 4.8 cm (SD 2.4, range 2 - 11 cm), average lesion surface area was 19.8 cm(2) (SD 17.7, range 2.2 - 72 cm(2)), and average duration of procedure was 79.9 min (SD 50.3 min, range 19 - 225 min). ESD could be conducted while the endoscope was retroflexed at its maximum in 26 cases. Four adverse events were observed: two diminutive perforations and two delayed bleeding occurrences treated conservatively. The R0 resection rate was 91.1 %. The catheter was obstructed in six occurrences of bleeding. Endoscopic submucosal dissection using high pressure injection of viscous macromolecular solutions is safe and effective in different parts of the digestive tract. It does not impede working with the endoscope in the maximal retroflexed position.

Weather, season, and daily stroke admissions in Hong Kong

NASA Astrophysics Data System (ADS)

Goggins, William B.; Woo, Jean; Ho, Suzanne; Chan, Emily Y. Y.; Chau, P. H.

2012-09-01

Previous studies examining daily temperature and stroke incidence have given conflicting results. We undertook this retrospective study of all stroke admissions in those aged 35 years old and above to Hong Kong public hospitals from 1999 through 2006 in order to better understand the effects of meteorological conditions on stroke risk in a subtropical setting. We used Poisson Generalized Additive Models with daily hemorrhagic (HS) and ischemic stroke (IS) counts separately as outcomes, and daily mean temperature, humidity, solar radiation, rainfall, air pressure, pollutants, flu consultation rates, day of week, holidays, time trend and seasonality as predictors. Lagged effects of temperature, humidity and pollutants were also considered. A total of 23,457 HS and 107,505 IS admissions were analyzed. Mean daily temperature had a strong, consistent, negative linear association with HS admissions over the range (8.2-31.8°C) observed. A 1°C lower average temperature over the same day and previous 4 days (lags 0-4) being associated with a 2.7% (95% CI: 2.0-3.4%, P < .0.0001) higher admission rate after controlling for other variables. This association was stronger among older subjects and females. Higher lag 0-4 average change in air pressure from previous day was modestly associated with higher HS risk. The association between IS and temperature was weaker and apparent only below 22°C, with a 1°C lower average temperature (lags 0-13) below this threshold being associated with a 1.6% (95% CI:1.0-2.2%, P < 0.0001) higher IS admission rate. Pollutant levels were not associated with HS or IS. Future studies should examine HS and IS risk separately.

Occurrence of the angiotensin-converting enzyme inhibiting tripeptides Val-Pro-Pro and Ile-Pro-Pro in different cheese varieties of Swiss origin.

PubMed

Bütikofer, U; Meyer, J; Sieber, R; Walther, B; Wechsler, D

2008-01-01

The contents of the 2 antihypertensive peptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) were determined in 101 samples from 10 different Swiss cheese varieties using HPLC with subsequent triple mass spectrometry. In the category of extra hard and hard cheeses, the Protected Denomination of Origin cheeses Berner Alpkäse and Berner Hobelkäse, L'Etivaz à rebibes, Le Gruyère, Sbrinz, Emmentaler (organic and conventional) and in the category of semihard cheeses, the varieties Tilsiter, Appenzeller 1/4 fat and full fat, Tête de Moine, and Vacherin fribourgeois were screened in the study. The average concentration of the sum of VPP and IPP in the screened cheese varieties varied to a large extent, and substantial variations were obtained for individual samples within the cheese varieties. The lowest average concentration of the 2 tri-petides was found in L'Etivaz à rebibes (n = 3) at 19.1 mg/kg, whereas Appenzeller 1/4 fat (n = 4) contained the greatest concentration at 182.2 mg/kg. In individual samples, the total concentration of VPP and IPP varied between 1.6 and 424.5 mg/kg. With the exception of a 10-yr-old cheese, VPP was always present at greater concentrations than IPP. Milk pretreatment, cultures, scalding conditions, and ripening time were identified as the key factors influencing the concentration of these 2 naturally occurring bioactive peptides in cheese. The results of the present study show that various traditional cheese varieties contain, on average, similar concentrations of the 2 antihypertensive peptides to the recently developed fermented milk products with blood pressure-lowering property. This may serve as a basis for the development of a functional cheese with blood pressure-lowering property.

Models to predict both sensible and latent heat transfer in the respiratory tract of Morada Nova sheep under semiarid tropical environment

NASA Astrophysics Data System (ADS)

Fonseca, Vinícius Carvalho; Saraiva, Edilson Paes; Maia, Alex Sandro Campos; Nascimento, Carolina Cardoso Nagib; da Silva, Josinaldo Araújo; Pereira, Walter Esfraim; Filho, Edgard Cavalcanti Pimenta; Almeida, Maria Elivânia Vieira

2017-05-01

The aim of this study was to build a prediction model both sensible and latent heat transfer by respiratory tract for Morada Nova sheep under field conditions in a semiarid tropical environment, using easily measured physiological and environmental parameters. Twelve dry Morada Nova ewes with an average of 3 ± 1.2 years old and average body weight of 32.76 ± 3.72 kg were used in a Latin square design 12 × 12 (12 days of records and 12 schedules). Tidal volume, respiratory rate, expired air temperature, and partial vapor pressure of the expired air were obtained from the respiratory facial mask and using a physiological measurement system. Ewes were evaluated from 0700 to 1900 h in each day under shade. A simple nonlinear model to estimate tidal volume as a function of respiratory rate was developed. Equation to estimate the expired air temperature was built, and the ambient air temperature was the best predictor together with relative humidity and ambient vapor pressure. In naturalized Morada Nova sheep, respiratory convection seems to be a mechanism of heat transfer of minor importance even under mild air temperature. Evaporation from the respiratory system increased together with ambient air temperature. At ambient air temperature, up to 35 °C respiratory evaporation accounted 90 % of the total heat lost by respiratory system, on average. Models presented here allow to estimate the heat flow from the respiratory tract for Morada Nova sheep bred in tropical region, using easily measured physiological and environmental traits as respiratory rate, ambient air temperature, and relative humidity.

Extra-large negative pressure wound therapy dressings for burns - Initial experience with technique, fluid management, and outcomes.

PubMed

Fischer, Sebastian; Wall, Jennifer; Pomahac, Bohdan; Riviello, Robert; Halvorson, Eric G

2016-03-01

The use of negative-pressure-wound-therapy (NPWT) is associated with improved outcomes in smaller burns. We report our experience using extra-large (XL) NPWT dressings to treat ≥15% total body surface area (TBSA) burned and describe our technique and early outcomes. We also provide NPWT exudate volume for predictive fluid resuscitation in these critically ill patients. We retrospectively reviewed patients treated with XL-NPWT from 2012 to 2014. Following excision/grafting, graft and donor sites were sealed with a layered NPWT dressing. We documented wound size, dressing size, NPWT outputs, graft take, wound infections, and length of stay (LOS). Mean NPWT exudate volume per %TBSA per day was calculated. Twelve burn patients (mean TBSA burned 30%, range 15-60%) were treated with XL-NPWT (dressing TBSA burned and skin graft donor sites range 17-44%). Average graft take was 97%. No wound infections occurred. Two patients had burns ≥50% TBSA and their LOS was reduced compared to ABA averages. XL-NPWT outputs peaked at day 1 after grafting followed by a steady decline until dressings were removed. Average XL-NPWT dressing output during the first 5 days was 101±66mL/%BSA covered per day. 2 patients developed acute kidney injury. The use of XL-NPWT to treat extensive burns is feasible with attention to application technique. NPWT dressings appear to improve graft take, and to decrease risk of infection, LOS, and pain and anxiety associated with wound care. Measured fluid losses can improve patient care in future applications of NPWT to large burn wounds. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Associations between cardiovascular disease and its risk factors with hearing loss-A cross-sectional analysis.

PubMed

Tan, H E; Lan, N S R; Knuiman, M W; Divitini, M L; Swanepoel, D W; Hunter, M; Brennan-Jones, C G; Hung, J; Eikelboom, R H; Santa Maria, P L

2018-02-01

To investigate the relationship between hearing loss and cardiovascular disease risk factors. Cross-sectional study. Participants were recruited between May 2010 and December 2015 and answered a health and risk factor questionnaire. Physical and biochemical assessments were performed. A community-based population. A total of 5107 participants born within the years 1946-1964 enrolled in the Busselton Healthy Ageing Study. Hearing was assessed behaviourally through the best ear pure-tone average (500, 1000, 2000, 4000 Hz), low-frequency average (250, 500, 1000 Hz) and high-frequency average (4000, 8000 Hz). Self-reported hearing loss, tinnitus and hyperacusis were assessed via questionnaire. Cardiovascular risk factors were assessed via a patient-completed questionnaire and objective measurements including blood pressure, body mass index, waist circumference, lipid profile and glycated haemoglobin. Of the participants, 54% were female, with the mean age of 58 years (range 45-69 years). Age, sex and family history of hearing loss were consistently strong determinants of hearing loss outcomes. After adjusting for these, obesity, current smoking, peripheral arterial disease and history of cardiovascular disease were significantly associated with pure-tone, low-frequency and high-frequency hearing loss. In addition, high blood pressure, triglyceride and glycated haemoglobin were significantly associated with low-frequency hearing loss. There was a graded association between hearing loss and Framingham Risk Score for cardiovascular risk (P<0.001). Established cardiovascular disease and individual and combined cardiovascular disease risk factors were found to be associated with hearing loss. Future research should prospectively investigate whether targeting cardiovascular disease can prevent hearing loss. © 2017 John Wiley & Sons Ltd.

Pressure probe study of the water relations of Phycomyces blakesleeanus sporangiophores

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.; Ortega, J. K.; Shropshire, W. Jr

1987-01-01

The physical characteristics which govern the water relations of the giant-celled sporangiophore of Phycomyces blakesleeanus were measured with the pressure probe technique and with nanoliter osmometry. These properties are important because they govern water uptake associated with cell growth and because they may influence expansion of the sporangiophore wall. Turgor pressure ranged from 1.1 to 6.6 bars (mean = 4.1 bars), and was the same for stage I and stage IV sporangiophores. Sporangiophore osmotic pressure averaged 11.5 bars. From the difference between cell osmotic pressure and turgor pressure, the average water potential of the sporangiophore was calculated to be about -7.4 bars. When sporangiophores were submerged under water, turgor remained nearly constant. We propose that the low cell turgor pressure is due to solutes in the cell wall solution, i.e., between the cuticle and the plasma membrane. Membrane hydraulic conductivity averaged 4.6 x 10(-6) cm s-1 bar-1, and was significantly greater in stage I sporangiophores than in stage IV sporangiophores. Contrary to previous reports, the sporangiophore is separated from the supporting mycelium by septa which prevent bulk volume flow between the two regions. The presence of a wall compartment between the cuticle and the plasma membrane results in anomalous osmosis during pressure clamp measurements. This behavior arises because of changes in solute concentration as water moves into or out of the wall compartment surrounding the sporangiophore. Theoretical analysis shows how the equations governing transient water flow are altered by the characteristics of the cell wall compartment.

Numerical Modeling of Flow Control in a Boundary-Layer-Ingesting Offset Inlet Diffuser at Transonic Mach Numbers

NASA Technical Reports Server (NTRS)

Allan Brian G.; Owens, Lewis, R.

2006-01-01

This paper will investigate the validation of a NASA developed, Reynolds-averaged Navier-Stokes (RANS) flow solver, OVERFLOW, for a boundary-layer-ingesting (BLI) offset (S-shaped) inlet in transonic flow with passive and active flow control devices as well as the baseline case. Numerical simulations are compared to wind tunnel results of a BLI inlet conducted at the NASA Langley 0.3-Meter Transonic Cryogenic Tunnel. Comparisons of inlet flow distortion, pressure recovery, and inlet wall pressures are performed. The numerical simulations are compared to the BLI inlet data at a freestream Mach number of 0.85 and a Reynolds number of approximately 2 million based on the length of the fan-face diameter. The numerical simulations with and without wind tunnel walls are performed, quantifying effects of the tunnel walls on the BLI inlet flow measurements. The wind tunnel test evaluated several different combinations of jet locations and mass flow rates as well as a vortex generator (VG) vane case. The numerical simulations will be performed on a single jet configuration for varying actuator mass flow rates at a fix inlet mass flow condition. Validation of the numerical simulations for the VG vane case will also be performed for varying inlet mass flow rates. Overall, the numerical simulations were able to predict the baseline circumferential flow distortion, DPCPavg, very well for comparisons made within the designed operating range of the BLI inlet. However the CFD simulations did predict a total pressure recovery that was 0.01 lower than the experiment. Numerical simulations of the baseline inlet flow also showed good agreement with the experimental inlet centerline surface pressures. The vane case showed that the CFD predicted the correct trends in the circumferential distortion for varying inlet mass flow but had a distortion level that was nearly twice as large as the experiment. Comparison to circumferential distortion measurements for a 15 deg clocked 40 probe rake indicated that the circumferential distortion levels are very sensitive to the symmetry of the flow and that a miss alignment of the vanes in the experiment could have resulted in this difference. The numerical simulations of the BLI inlet with jets showed good agreement with the circumferential inlet distortion levels for a range of jet actuator mass flow ratios at a fixed inlet mass flow rate. The CFD simulations for the jet case also predicted an average total pressure recovery that was 0.01 lower than the experiment as was seen in the baseline. Comparison of the flow features the jet case revealed that the CFD predicted a much larger vortex at the engine fan-face when compare to the experiment.

Effects of total pressure on non-grey gas radiation transfer in oxy-fuel combustion using the LBL, SNB, SNBCK, WSGG, and FSCK methods

NASA Astrophysics Data System (ADS)

Chu, Huaqiang; Gu, Mingyan; Consalvi, Jean-Louis; Liu, Fengshan; Zhou, Huaichun

2016-03-01

The effects of total pressure on gas radiation heat transfer are investigated in 1D parallel plate geometry containing isothermal and homogeneous media and an inhomogeneous and non-isothermal CO2-H2O mixture under conditions relevant to oxy-fuel combustion using the line-by-line (LBL), statistical narrow-band (SNB), statistical narrow-band correlated-k (SNBCK), weighted-sum-of-grey-gases (WSGG), and full-spectrum correlated-k (FSCK) models. The LBL calculations were conducted using the HITEMP2010 and CDSD-1000 databases and the LBL results serve as the benchmark solution to evaluate the accuracy of the other models. Calculations of the SNB, SNBCK, and FSCK were conducted using both the 1997 EM2C SNB parameters and their recently updated 2012 parameters to investigate how the SNB model parameters affect the results under oxy-fuel combustion conditions at high pressures. The WSGG model considered is the recently developed one by Bordbar et al. [19] for oxy-fuel combustion based on LBL calculations using HITEMP2010. The total pressure considered ranges from 1 up to 30 atm. The total pressure significantly affects gas radiation transfer primarily through the increase in molecule number density and only slightly through spectral line broadening. Using the 1997 EM2C SNB model parameters the accuracy of SNB and SNBCK is very good and remains essentially independent of the total pressure. When using the 2012 EM2C SNB model parameters the SNB and SNBCK results are less accurate and their error increases with increasing the total pressure. The WSGG model has the lowest accuracy and the best computational efficiency among the models investigated. The errors of both WSGG and FSCK using the 2012 EM2C SNB model parameters increase when the total pressure is increased from 1 to 10 atm, but remain nearly independent of the total pressure beyond 10 atm. When using the 1997 EM2C SNB model parameters the accuracy of FSCK only slightly decreases with increasing the total pressure.

Cloth media filtration and membrane microfiltration: serial operation.

PubMed

Tooker, Nicholas Brewster; Darby, Jeannie L

2007-02-01

A combined system comprised of a cloth media filter and a membrane microfilter operated in series was used to treat secondary effluent. The study objective was to investigate the effect of premembrane filtration on the maximum sustainable membrane flux, transmembrane pressure, and effluent quality. The maximum sustainable time-averaged flux under predefined operating conditions (i.e., 15-minute process cycle, 24-hour chemical cleaning cycle, and 30-day intensive cleaning cycle) was 127 L/m(2)x h. Typical flux rates for secondary effluent ranged from 40 to 55 L/m(2) x h. Effluent water quality from the combined system was high and independent of membrane flux and influent quality. Average membrane effluent water quality values were 0.04 NTU for turbidity and 1.4 mg/L for 5-day biochemical oxygen demand. Neither total nor fecal coliforms were detected. Based on the results presented herein, prefiltration would provide an annualized cost savings of approximately 12% over microfiltration alone for a 3.8 x 10(3) m(3)/d treatment facility.

Satellite-derived ice data sets no. 2: Arctic monthly average microwave brightness temperatures and sea ice concentrations, 1973-1976

NASA Technical Reports Server (NTRS)

Parkinson, C. L.; Comiso, J. C.; Zwally, H. J.

1987-01-01

A summary data set for four years (mid 70's) of Arctic sea ice conditions is available on magnetic tape. The data include monthly and yearly averaged Nimbus 5 electrically scanning microwave radiometer (ESMR) brightness temperatures, an ice concentration parameter derived from the brightness temperatures, monthly climatological surface air temperatures, and monthly climatological sea level pressures. All data matrices are applied to 293 by 293 grids that cover a polar stereographic map enclosing the 50 deg N latitude circle. The grid size varies from about 32 X 32 km at the poles to about 28 X 28 km at 50 deg N. The ice concentration parameter is calculated assuming that the field of view contains only open water and first-year ice with an ice emissivity of 0.92. To account for the presence of multiyear ice, a nomogram is provided relating the ice concentration parameter, the total ice concentration, and the fraction of the ice cover which is multiyear ice.

A Data Mining Project to Identify Cardiovascular Related Factors That May Contribute to Changes in Visual Acuity Within the US Astronaut Corps

NASA Technical Reports Server (NTRS)

Westby, Christian M.; Stein, Sydney P.; Platts, Steven H.

2011-01-01

Many of the cardiovascular-related adaptations that occur in the microgravity environment are due, in part, to a well-characterized cephalad-fluid shift that is evidenced by facial edema and decreased lower limb circumference. It is believed that most of these alterations occur as a compensatory response necessary to maintain a "normal" blood pressure and cardiac output while in space. However, data from both flight and analog research suggest that in some instances these microgravity-induced alterations may contribute to cardiovascular-related pathologies. Most concerning is the potential relation between the vision disturbances experienced by some long duration crewmembers and changes in cerebral blood flow and intra-ocular pressure. The purpose of this project was to identify cardiovascular measures that may potentially distinguish individuals at risk for visual disturbances after long duration space flight. Toward this goal, we constructed a dataset from Medical Operation tilt/stand test evaluations pre- (days L-15-L-5) and immediate post-flight (day R+0) on 20 (3 females, 17 males). We restricted our evaluation to only crewmembers who participated in both shuttle and space station missions. Data analysis was performed using both descriptive and analytical methods (Stata 11.2, College Station, TX) and are presented as means +/- 95% CI. Crewmembers averaged 5207 (3447 - 8934) flight hours across both long (MIR-23 through Expedition16) and short (STS-27 through STS-101) duration missions between 1988 and 2008. The mean age of the crew at the time of their most recent shuttle flight was 41 (34-44) compared to 47 (40-54) years during their time on station. In order to focus our analysis (we did not have codes to separate out subjects by symptomotology) , we performed a visual inspection of each cardiovascular measures captured during testing and plotted them against stand time, pre- to post-flight, and between mission duration. It was found that pulse pressure most clearly differentiated the two mission types. Statistical analysis confirmed that pulse pressure was significantly higher before [45.6; (42.1 to 49.1)] and after [50.7; (46.9 to 54.6)] time on station compared with their most recent shuttle flight [31.6 (27.8 to 35.4), and 32.2 (28.3 to 36.0) respectively] even after correcting differences in age and cumulative number of mission hours. Without knowing the identity of which long duration crewmembers demonstrated visual changes, we were limited to examining whether certain crew regulate components of pulse pressure, systolic and diastolic blood pressure, differently due to microgravity exposure. To that end, we stratified crew into tertiles based on either their pre-flight measure of systolic or diastolic blood pressure. Those crew in the highest tertile for both systolic (lower tertile (n=8; 103-111), middle tertile (n=7; 113-121), and upper tertile (n=5; 125-136) and diastolic blood pressure (lower tertile (n=8; 58-64), middle tertile (n=7; 67-73), and upper tertile (n=5; 75-81) demonstrated less variability in pulse pressure between R+0 and L-10 (Figure 2). Interestingly, those crewmembers with the highest resting systolic blood pressure demonstrated either no change or in some instances an increase in total peripheral resistance, where those in the lower tertiles had lower values of total peripheral resistance compared to pre-flight levels. In this study, it was found that crewmembers in the highest tertile for both systolic and diastolic blood pressure demonstrated less variability in pulse pressure and that the decrease in variability was due in part to lower levels of compliance as indicated by similar or higher levels of total peripheral resistance after compared with before flight levels. Whether there is a relation between blood pressure regulation and total peripheral resistance in crew presenting with negative changes in visual acuity remains unknown.

COAL/POLYMER COPROCESSING WITH EFFICIENT USE OF HYDROGEN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dr. Linda J. Broadbelt; Matthew J. DeWitt; Hsi-Wu Wong

2000-09-30

The final project period was devoted to investigating the binary mixture pyrolysis of polypropylene and polystyrene. Their interactions were assessed in order to provide a baseline for experiments with multicomponent mixtures of polymers with coal. Pyrolysis of polypropylene, polystyrene and their binary mixture was investigated at temperatures of 350 C and 420 C with reaction times from 1 to 180 minutes. Two different loadings, 10 mg and 20 mg, were studied for neat polypropylene and polystyrene to assess the effect of total pressure on product yields and selectivities. For neat pyrolysis of polypropylene, total conversion was much higher at 420more » C, and no significant effect of loading on the total conversion was observed. Four classes of products, alkanes, alkenes, dienes, and aromatic compounds, were observed, and their distribution was explained by a typical free radical mechanism. For neat polystyrene pyrolysis, conversion reached approximately 75% at 350 C, while at 420 C the conversion reached a maximum around 90% at 10 minutes and decreased at longer times because of condensation reactions. The selectivities to major products were slightly different for the two different loadings due to the effect of total reaction pressure on secondary reactions. For binary mixture pyrolysis, the overall conversion was higher than the average of the two neat cases. The conversion of polystyrene remained the same, but a significant enhancement in the polypropylene conversion was observed. This suggests that the less reactive polypropylene was initiated by polystyrene-derived radicals. These results are summarized in detail in an attached manuscript that is currently in preparation. The other results obtained during the lifetime of this grant are documented in the set of attached manuscripts.« less

Pulmonary artery pressure-guided heart failure management: US cost-effectiveness analyses using the results of the CHAMPION clinical trial.

PubMed

Martinson, Melissa; Bharmi, Rupinder; Dalal, Nirav; Abraham, William T; Adamson, Philip B

2017-05-01

Haemodynamic-guided heart failure (HF) management effectively reduces decompensation events and need for hospitalizations. The economic benefit of clinical improvement requires further study. An estimate of the cost-effectiveness of haemodynamic-guided HF management was made based on observations published in the randomized, prospective single-blinded CHAMPION trial. A comprehensive analysis was performed including healthcare utilization event rates, survival, and quality of life demonstrated in the randomized portion of the trial (18 months). Markov modelling with Monte Carlo simulation was used to approximate comprehensive costs and quality-adjusted life years (QALYs) from a payer perspective. Unit costs were estimated using the Truven Health MarketScan database from April 2008 to March 2013. Over a 5-year horizon, patients in the Treatment group had average QALYs of 2.56 with a total cost of US$56 974; patients in the Control group had QALYs of 2.16 with a total cost of US$52 149. The incremental cost-effectiveness ratio (ICER) was US$12 262 per QALY. Using comprehensive cost modelling, including all anticipated costs of HF and non-HF hospitalizations, physician visits, prescription drugs, long-term care, and outpatient hospital visits over 5 years, the Treatment group had a total cost of US$212 004 and the Control group had a total cost of US$200 360. The ICER was US$29 593 per QALY. Standard economic modelling suggests that pulmonary artery pressure-guided management of HF using the CardioMEMS™ HF System is cost-effective from the US-payer perspective. This analysis provides the background for further modelling in specific country healthcare systems and cost structures. © 2016 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.

Effect of overtime work on 24-hour ambulatory blood pressure.

PubMed

Hayashi, T; Kobayashi, Y; Yamaoka, K; Yano, E

1996-10-01

Recently, the adverse effects of long working hours on the cardiovascular systems of workers in Japan, including "Karoshi" (death from overwork), have been the focus of social concern. However, conventional methods of health checkups are often unable to detect the early signs of such adverse effects. To evaluate the influence of overtime work on the cardiovascular system, we compared 24-hour blood pressure measurements among several groups of male white-collar workers. As a result, for those with normal blood pressure and those with mild hypertension, the 24-hour average blood pressure of the overtime groups was higher than that of the control groups; for those who periodically did overtime work, the 24-hour average blood pressure and heart rate during the busy period increased. These results indicate that the burden on the cardiovascular system of white-collar workers increases with overtime work.

Elements of an improved model of debris‐flow motion

USGS Publications Warehouse

Iverson, Richard M.

2009-01-01

A new depth‐averaged model of debris‐flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore‐fluid pressure. Non‐hydrostatic pore‐fluid pressure is produced by dilatancy, a state‐dependent property that links the depth‐averaged shear rate and volumetric strain rate of the granular phase. Pore‐pressure changes caused by shearing allow the model to exhibit rate‐dependent flow resistance, despite the fact that the basal shear traction involves only rate‐independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore‐pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states.

Elements of an improved model of debris-flow motion

USGS Publications Warehouse

Iverson, R.M.

2009-01-01

A new depth-averaged model of debris-flow motion describes simultaneous evolution of flow velocity and depth, solid and fluid volume fractions, and pore-fluid pressure. Non-hydrostatic pore-fluid pressure is produced by dilatancy, a state-dependent property that links the depth-averaged shear rate and volumetric strain rate of the granular phase. Pore-pressure changes caused by shearing allow the model to exhibit rate-dependent flow resistance, despite the fact that the basal shear traction involves only rate-independent Coulomb friction. An analytical solution of simplified model equations shows that the onset of downslope motion can be accelerated or retarded by pore-pressure change, contingent on whether dilatancy is positive or negative. A different analytical solution shows that such effects will likely be muted if downslope motion continues long enough, because dilatancy then evolves toward zero, and volume fractions and pore pressure concurrently evolve toward steady states. ?? 2009 American Institute of Physics.

Forest biomass flow for fuel wood, fodder and timber security among tribal communities of Jharkhand.

PubMed

Islam, M A; Quli, S M S; Rai, R; Ali, Angrej; Gangoo, S A

2015-01-01

The study investigated extraction and consumption pattern of fuel wood, fodder and timber and forest biomass flow for fuel wood, fodder and timber security among tribal communities in Bundu block of Ranchi district in Jharkhand (India). The study is based on personal interviews of the selected respondents through structured interview schedule, personal observations and participatory rural appraisal tools i.e. key informant interviews and focus group discussions carried out in the sample villages, using multi-stage random sampling technique. The study revealed that the total extraction of fuel wood from different sources in villages was 2978.40 tons annum(-1), at the rate of 0.68 tons per capita annum(-1), which was mostly consumed in cooking followed by cottage industries, heating, community functions and others. The average fodder requirement per household was around 47.77 kg day(-1) with a total requirement of 14227.34 tons annum(-1). The average timber requirement per household was computed to be 0.346 m3 annum(-1) accounting for a total timber demand of 282.49 m3 annum(-1), which is mostly utilized in housing, followed by agricultural implements, rural furniture, carts and carriages, fencing, cattle shed/ store house and others. Forest biomass is the major source of fuel wood, fodder and timber for the primitive societies of the area contributing 1533.28 tons annum(-1) (51.48%) of the total fuel wood requirement, 6971.55 tons annum(-1) (49.00%) of the total fodder requirement and 136.36 m3 annum(-1) (48.27%) of the total timber requirement. The forest biomass is exposed to enormous pressure for securing the needs by the aboriginal people, posing great threat to biodiversity and environment of the region. Therefore, forest biomass conservation through intervention of alternative avenues is imperative to keep pace with the current development and future challenges in the area.

An in vitro comparison of tracheostomy tube cuffs

PubMed Central

Maguire, Seamus; Haury, Frances; Jew, Korinne

2015-01-01

Introduction The Shiley™ Flexible adult tracheostomy tube with TaperGuard™ cuff has been designed through its geometry, materials, diameter, and wall thickness to minimize micro-aspiration of fluids past the cuff and to provide an effective air seal in the trachea while also minimizing the risk of excessive contact pressure on the tracheal mucosa. The cuff also has a deflated profile that may allow for easier insertion through the stoma site. This unique design is known as the TaperGuard™ cuff. The purpose of the observational, in vitro study reported here was to compare the TaperGuard™ taper-shaped cuff to a conventional high-volume low-pressure cylindrical-shaped cuff (Shiley™ Disposable Inner Cannula Tracheostomy Tube [DCT]) with respect to applied tracheal wall pressure, air and fluid sealing efficacy, and insertion force. Methods Three sizes of tracheostomy tubes with the two cuff types were placed in appropriately sized tracheal models and lateral wall pressure was measured via pressure-sensing elements on the inner surface. Fluid sealing performance was assessed by inflating the cuffs within the tracheal models (25 cmH2O), instilling water above the cuff, and measuring fluid leakage past the cuff. To measure air leak, tubes were attached to a test lung and ventilator, and leak was calculated by subtracting the average exhaled tidal volume from the average delivered tidal volume. A tensile test machine was used to measure insertion force for each tube with the cuff deflated to simulate clinical insertion through a stoma site. Results The average pressure exerted on the lateral wall of the model trachea was lower for the taper-shaped cuff than for the cylindrical cuff under all test conditions (P<0.05). The taper-shaped cuff also demonstrated a more even, lower pressure distribution along the lateral wall of the model trachea. The average air and fluid seal performance with the taper-shaped cuff was significantly improved, when compared to the cylindrical-shaped cuff, for each tube size tested (P<0.05). The insertion force for the taper-shaped cuff was ~40% less than that for the cylindrical-shaped cuff. Conclusion In a model trachea, the Shiley™ Flexible Adult tracheostomy tube with TaperGuard™ cuff, when compared to the Shiley™ Disposable Inner Cannula Tracheostomy tube with cylindrical cuff, exerted a lower average lateral wall pressure and a more evenly distributed pressure. In addition, it provided more effective fluid and air seals and required less force to insert. PMID:25960679

Effect of pillow height on the biomechanics of the head-neck complex: investigation of the cranio-cervical pressure and cervical spine alignment

PubMed Central

Yang, Hui; Zhou, Yan; Lin, Jin

2016-01-01

Background While appropriate pillow height is crucial to maintaining the quality of sleep and overall health, there are no universal, evidence-based guidelines for pillow design or selection. We aimed to evaluate the effect of pillow height on cranio-cervical pressure and cervical spine alignment. Methods Ten healthy subjects (five males) aged 26 ± 3.6 years were recruited. The average height, weight, and neck length were 167 ± 9.3 cm, 59.6 ± 11.9 kg, and 12.9 ± 1.2 cm respectively. The subjects lay on pillows of four different heights (H0, 110 mm; H1, 130 mm; H2, 150 mm; and H3, 170 mm). The cranio-cervical pressure distribution over the pillow was recorded; the peak and average pressures for each pillow height were compared by one-way ANOVA with repeated measures. Cervical spine alignment was studied using a finite element model constructed based on data from the Visible Human Project. The coordinate of the center of each cervical vertebra were predicted for each pillow height. Three spine alignment parameters (cervical angle, lordosis distance and kyphosis distance) were identified. Results The average cranial pressure at pillow height H3 was approximately 30% higher than that at H0, and significantly different from those at H1 and H2 (p < 0.05). The average cervical pressure at pillow height H0 was 65% lower than that at H3, and significantly different from those at H1 and H2 (p < 0.05). The peak cervical pressures at pillow heights H2 and H3 were significantly different from that at H0 (p < 0.05). With respect to cervical spine alignment, raising pillow height from H0 to H3 caused an increase of 66.4% and 25.1% in cervical angle and lordosis distance, respectively, and a reduction of 43.4% in kyphosis distance. Discussion Pillow height elevation significantly increased the average and peak pressures of the cranial and cervical regions, and increased the extension and lordosis of the cervical spine. The cranio-cervical pressures and cervical spine alignment were height-specific, and they were believed to reflect quality of sleep. Our results provide a quantitative and objective evaluation of the effect of pillow height on the biomechanics of the head-neck complex, and have application in pillow design and selection. PMID:27635354

76 FR 3142 - Notice of Annual Adjustment of the Cap on Average Total Assets That Defines Community Financial...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-19

... FEDERAL HOUSING FINANCE AGENCY [No. 2011-N-01] Notice of Annual Adjustment of the Cap on Average.... ACTION: Notice. SUMMARY: The Federal Housing Finance Agency (FHFA) has adjusted the cap on average total... average total assets below a statutory cap. See 12 U.S.C. 1422(10)(A); 12 CFR 1263.1. The Bank Act was...

Numerical study on the instabilities in H2-air rotating detonation engines

NASA Astrophysics Data System (ADS)

Liu, Yan; Zhou, Weijiang; Yang, Yunjun; Liu, Zhou; Wang, Jianping

2018-04-01

Numerical simulations of rotating detonation engines (RDEs) are performed using two-dimensional Euler equations and a detailed chemistry model of H2-air. Two propagation modes, the one-wave mode and the two-wave mode, are observed in the RDEs. The instabilities of the RDEs are studied and analyzed specifically. A low frequency instability and a high frequency instability are found from the pressure-time trace measured at a fixed location and the average density-time trace of the RDEs. For the low frequency instability, the pressure peak of the pressure-time trace oscillates with a low frequency while the average density is stable. The deviation between the measurement location and the location of the detonation wave results in the low frequency instability. For the high frequency instability, the average density of the RDEs oscillates regularly with a single frequency while the pressure oscillates irregularly with several frequencies. The oscillation of the detonation wave height results in the high frequency instability. Furthermore, the low frequency instability and the high frequency instability both occur in the one-wave and two-wave mode RDEs.

Liquid Fuel Emulsion Jet-in-Crossflow Penetration and Dispersion Under High Pressure Conditions

NASA Astrophysics Data System (ADS)

Gomez, Guillermo Andres

The current work focuses on the jet-in-crossflow penetration and dispersion behavior of water-in-oil emulsions in a high pressure environment. Both fuel injection strategies of using a water-in-oil emulsion and a jet-in-crossflow have demonstrated unique benefits in improving gas turbine performance from an emissions and efficiency standpoint. A jet-in-crossflow is very practical for use in gas turbine engines, rocket propulsion, and aircraft engines since it utilizes already available crossflow air to atomize fuel. Injecting water into a combustion chamber in the form of a water-in-oil emulsion allows for pollutant emissions reduction while reducing efficiency loses that may result from using a separate water or steam injection circuit. Dispersion effects on oil droplets are expected, therefore investigating the distribution of both oil and water droplets in the crossflow is an objective in this work. Understanding the synchronization and injection behavior of the two strategies is of key interest due to their combined benefits. A water-to-oil ratio and an ambient pressure parameter are developed for emulsion jet-in-crossflow trajectories. To this end, a total of 24 emulsion jet-in-crossflow tests were performed with varying ambient pressures of 2-8 atm and momentum flux ratios of 50, 85, and 120. Sobel edge filtering was applied to each averaged image obtained from a high speed video of each test case. Averaged and filtered images were used to resolve top and bottom edges of the trajectory in addition to the overall peak intensity up to 40 mm downstream of the injection point. An optimized correlation was established and found to differ from literature based correlations obtained under atmospheric pressure conditions. Overall it was found that additional parameters were not necessary for the top edge and peak intensity correlations, but a need for a unique emulsion bottom edge and width trajectory correlation was recognized. In addition to investigating emulsion jet-in-crossflow trajectory correlations, a unique Dual Planar Laser Induced Fluorescence (Dual-PLIF) method was applied for the first time on emulsions at elevated pressure conditions. From the Dual-PLIF results, qualitative observations provided insight into the unique dispersion of oil and water concentrations within a cross-sectional plane down stream of the jet-in-crossflow injection.

Noninvasive measurement of beat-to-beat arterial blood pressure by the Korotkoff sound delay time.

PubMed

Xiang, Haiyan; Liu, Yanyong; Li, Yinhua; Qin, Yufei; Yu, Mengsun

2012-02-01

To propose a novel noninvasive beat-to-beat arterial blood pressure measurement method based on the Korotkoff sound delay time (KDT) and evaluate its accuracy in preliminary experiments. KDT decreases as the cuff pressure P deflates, which can be described by a function KDT=f (P). Actually, KDT is a function of arterial transmural pressure. Therefore, the variation in blood pressure can be obtained by the transmural pressure, which is estimated by the KDT. Holding the cuff pressure at an approximate constant pressure between systolic pressure and diastolic pressure, the variation in blood pressure ΔEBP between successive heartbeats can be estimated according to KDT and f'(p), which represents the variation of KDT corresponding to unit pressure. Then the blood pressure for each heartbeat can be obtained by accumulating the ΔEBP. Invasive and noninvasive blood pressure values of six participants were measured simultaneously to evaluate the method. The average of the correlation coefficients between the invasive mean arterial pressure (MAP) and the KDT for six participants was -0.91. The average of the correlation coefficients between the invasive MAP and the estimated mean blood pressure (EBP) was 0.92. The mean difference between EBP and MAP was 0.51 mmHg, and the SD was 2.65 mmHg. The mean blood pressure estimated by the KDT is consistent with the invasive MAP. The beat-to-beat blood pressure estimated by KDT provides an accurate estimate of MAP in the preliminary experiments and represents a potential acceptable alternative to invasive blood pressure monitoring during laboratory studies.

Aerodynamic Resistance of a Ball-Tube Mill During Transport of a Polydisperse Coal Gas Suspension

NASA Astrophysics Data System (ADS)

Ivanov, S. D.; Kudryashov, A. N.; Oshchepkov, V. V.

2018-03-01

Analysis of experimental data on aerodynamic resistance of a ball-tube mill is given. It is shown that this resistance has two components brought about by the pressure losses resulting from the injection of dust particles into the main flow after coal grinding and from the transport of homogeneous gas suspension flow. A dimensionless equation has been obtained for the dependence of the pressure loss in flow of a homogeneous dust-air mixture on Reynolds number. Functional dependences of the mean-square velocity of the floating of coal particles and of their average diameter on the polydispersity parameters of coal dust have been found. An empirical dependence of pressure loss due to the injection of a polydisperse coal gas suspension into the main flow on the average velocity of floating of coal particles, their average size, and on the size of the mill has been obtained.

Aerodynamic Resistance of a Ball-Tube Mill During Transport of a Polydisperse Coal Gas Suspension

NASA Astrophysics Data System (ADS)

Ivanov, S. D.; Kudryashov, A. N.; Oshchepkov, V. V.

2018-05-01

Analysis of experimental data on aerodynamic resistance of a ball-tube mill is given. It is shown that this resistance has two components brought about by the pressure losses resulting from the injection of dust particles into the main flow after coal grinding and from the transport of homogeneous gas suspension flow. A dimensionless equation has been obtained for the dependence of the pressure loss in flow of a homogeneous dust-air mixture on Reynolds number. Functional dependences of the mean-square velocity of the floating of coal particles and of their average diameter on the polydispersity parameters of coal dust have been found. An empirical dependence of pressure loss due to the injection of a polydisperse coal gas suspension into the main flow on the average velocity of floating of coal particles, their average size, and on the size of the mill has been obtained.

Drag of two-dimensional small-amplitude symmetric and asymmetric wavy walls in turbulent boundary layers

NASA Technical Reports Server (NTRS)

Lin, J. C.; Walsh, M. J.; Balasubramanian, R.

1984-01-01

Included are results of an experimental investigation of low-speed turbulent flow over multiple two-dimensional transverse rigid wavy surfaces having a wavelength on the order of the boundary-layer thickness. Data include surface pressure and total drag measurements on symmetric and asymmetric wall waves under a low-speed turbulent boundary-layer flow. Several asymmetric wave configurations exhibited drag levels below the equivalent symmetric (sine) wave. The experimental results compare favorably with numerical predictions from a Reynolds-averaged Navier-Stokes spectral code. The reported results are of particular interest for the estimation of drag, the minimization of fabrication waviness effects, and the study of wind-wave interactions.

Radiological impact of airborne effluents of coal and nuclear plants.

PubMed

McBride, J P; Moore, R E; Witherspoon, J P; Blanco, R E

1978-12-08

Radiation doses from airborne effluents of model coal-fired and nuclear power plants (1000 megawatts electric) are compared. Assuming a 1 percent ash release to the atmosphere (Environmental Protection Agency regulation) and 1 part per million of uranium and 2 parts per million of thorium in the coal (approximately the U.S. average), population doses from the coal plant are typically higher than those from pressurized-water or boiling-water reactors that meet government regulations. Higher radionuclide contents and ash releases are common and would result in increased doses from the coal plant. The study does not assess the impact of non-radiological pollutants or the total radiological impacts of a coal versus a nuclear economy.

Screening for Atrial Fibrillation in Patients ≥65 Years Using an Automatic Blood Pressure Monitor in a Skilled Nursing Facility.

PubMed

Wiesel, Joseph; Salomone, Thomas J

2017-10-15

Early detection of asymptomatic atrial fibrillation (AF) provides an opportunity to treat patients to reduce their risk of stroke. Long-term residents of skilled nursing facilities frequently have multiple risk factors for strokes due to AF and may benefit from screening for AF. Patients in a skilled nursing facility 65 years and older, without a history of AF and without a pacemaker or defibrillator, were evaluated using a Microlife WatchBP Home A automatic blood pressure monitor that can detect AF when set to a triple reading mode. Those with readings positive for AF were evaluated with a standard 12-lead electrocardiogram (ECG) or a 30-second single-channel ECG to confirm the presence of AF. A total of 101 patients were screened with an average age of 78 years, and 48 (48%) were female. Nine automatic blood pressure monitor readings were positive for possible AF. Of those, 7 (6.9%, 95% confidence intervals 3.0% to 14.2%) had AF confirmed with ECG. Only 2 (2%, 95% confidence interval 0.3% to 7.7%) were false-positive readings. One-time screening for AF using an automatic blood pressure monitor in a skilled nursing facility resulted in a high number of patients with newly diagnosed AF. Copyright © 2017 Elsevier Inc. All rights reserved.

Theoretical and practical knowledge of Nursing professionals on indirect blood pressure measurement at a coronary care unit

PubMed Central

Machado, Juliana Pereira; Veiga, Eugenia Velludo; Ferreira, Paulo Alexandre Camargo; Martins, José Carlos Amado; Daniel, Ana Carolina Queiroz Godoy; Oliveira, Amanda dos Santos; da Silva, Patrícia Costa dos Santos

2014-01-01

Objective To determine and to analyze the theoretical and practical knowledge of Nursing professionals on indirect blood pressure measurement. Methods This cross-sectional study included 31 professionals of a coronary care unit (86% of the Nursing staff in the unit). Of these, 38.7% of professionals were nurses and 61.3% nurse technicians. A validated questionnaire was used to theoretical evaluation and for practice assessment the auscultatory technique was applied in a simulation environment, under a non-participant observation. Results To the theoretical knowledge of the stages of preparation of patient and environment, 12.9% mentioned 5-minute of rest, 48.4% checked calibration, and 29.0% chose adequate cuff width. A total of 64.5% of professionals avoided rounding values, and 22.6% mentioned the 6-month deadline period for the equipment calibration. On average, in practice assessment, 65% of the steps were followed. Lacks in knowledge were primary concerning lack of checking the device calibration and stethoscope, measurement of arm circumference to choose the cuff size, and the record of arm used in blood pressure measurement. Conclusion Knowledge was poor and had disparities between theory and practice with evidence of steps taken without proper awareness and lack of consideration of important knowledge during implementation of blood pressure measurement. Educational and operational interventions should be applied systematically with institutional involvement to ensure safe care with reliable values. PMID:25295455

A Model for the Oxidation of C/SiC Composite Structures

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

2003-01-01

A mathematical theory and an accompanying numerical scheme have been developed for predicting the oxidation behavior of C/SiC composite structures. The theory is derived from the mechanics of the flow of ideal gases through a porous solid. Within the mathematical formulation, two diffusion mechanisms are possible: (1) the relative diffusion of one species with respect to the mixture, which is concentration gradient driven and (2) the diffusion associated with the average velocity of the gas mixture, which is total gas pressure gradient driven. The result of the theoretical formulation is a set of two coupled nonlinear differential equations written in terms of the oxidant and oxide partial pressures. The differential equations must be solved simultaneously to obtain the partial vapor pressures of the oxidant and oxides as a function of space and time. The local rate of carbon oxidation is determined as a function of space and time using the map of the local oxidant partial vapor pressure along with the Arrhenius rate equation. The nonlinear differential equations are cast into matrix equations by applying the Bubnov-Galerkin weighted residual method, allowing for the solution of the differential equations numerically. The end result is a numerical scheme capable of determining the variation of the local carbon oxidation rates as a function of space and time for any arbitrary C/SiC composite structures.

Temperature dependence of Lorentz air-broadening and pressure-shift coefficients of (12)CH4 lines in the 2.3-micron spectral region

NASA Technical Reports Server (NTRS)

Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Rinsland, C. P.

1994-01-01

High-resolution (0.01/cm) absorption spectra of lean mixtures of CH4 in dry air were recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak at various temperatures between 24 and -61 C. The spectra have been analyzed to determine the values at room temperature of pressure-broadened widths and pressure-induced shifts of more than 740 transitions. The temperature dependence of air-broadened widths and pressure-induced shifts was deduced for approx. 370 transitions in the nu(sub 1) + nu(sub 4), nu(sub 3) + nu(sub 4), and nu(sub 2) + nu(sub 3) bands of (12)CH4 located between 4118 and 4615/cm. These results were obtained by analyzing a total of 29 spectra simultaneously using a multi-spectral non-linear least-squares fitting technique. This new technique allowed the determination of correlated spectral line parameters (e.g. intensity and broadening coefficient) better than the procedure of averaging values obtained by fitting the spectra individually. This method also provided a direct determination of the uncertainties in the retrieved parameters due to random errors. For each band analysed in this study the dependence of the various spectral line parameters upon the tetrahedral symmetry species and the rotational quantum numbers of the transitions is also presented.

A Descriptive, Retrospective Study of Using an Oblique Downward-design Gluteus Maximus Myocutaneous Flap for Reconstruction of Ischial Pressure Ulcers.

PubMed

Chou, Chang-Yi; Sun, Yu-Shan; Shih, Yu-Jen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng; Dai, Niann-Tzyy; Lin, Chin-Ta

2018-03-01

Despite advances in reconstruction techniques, ischial pressure ulcers continue to present a challenge for the plastic surgeon. The purpose of this retrospective study was to evaluate outcomes of using an oblique downward gluteus maximus myocutaneous (GMM) flap for coverage of grade IV ischial ulcers. Data regarding defect size, flap size, operation time, duration of wound healing, and surgical outcome were abstracted from the medical records of patients whose ischial pressure ulcers had been reconstructed using GMM island flaps between January 2010 and December 2015. The 22 patients comprised 15 men and 7 women with a mean age of 52 (range 16-81) years. Twenty (20) had paraplegia, 6 had a recurrent ischial ulcer, 2 were bedridden following a cerebrovascular accident, 1 had a myelomeningocele status post operation, and 19 were spinal cord injury patients. Follow-up time ranged from 6 to 40 months. Pressure ulcer size ranged from 3 cm x 2 cm to 10 cm x 5 cm (average 22.3 cm2). The average flap size was 158 cm2 (15.9 cm x 9.7 cm); the largest was 286 cm2 (22 cm x 13 cm). The operating time ranged from 52 minutes to 110 minutes (average, 80 minutes). In 2 cases, wound dehiscence occurred but completely healed after resuturing. One (1) ischial pressure ulcer recurred 6 months following surgery and was successfully covered with a pedicled anterolateral thigh flap. No recurrences or problems were observed in the remaining 20 patients. Time to complete wound healing ranged from 14 to 24 days (average 17.8 days). Treatment of ischial pressure ulcers with GMM flaps allowed for an easy, simple procedure that provided the adequate thickness of soft tissue needed to cover the bony prominence, fill dead space, and cover the lesion. This technique was a reliable and safe reconstructive modality for the management of ischial pressure ulcers, even in recurrent cases.

Optimization and characterization of high pressure homogenization produced chemically modified starch nanoparticles.

PubMed

Ding, Yongbo; Kan, Jianquan

2017-12-01

Chemically modified starch (RS4) nanoparticles were synthesized through homogenization and water-in-oil mini-emulsion cross-linking. Homogenization was optimized with regard to z-average diameter by using a three-factor-three-level Box-Behnken design. Homogenization pressure (X 1 ), oil/water ratio (X 2 ), and surfactant (X 3 ) were selected as independent variables, whereas z-average diameter was considered as a dependent variable. The following optimum preparation conditions were obtained to achieve the minimum average size of these nanoparticles: 50 MPa homogenization pressure, 10:1 oil/water ratio, and 2 g surfactant amount, when the predicted z-average diameter was 303.6 nm. The physicochemical properties of these nanoparticles were also determined. Dynamic light scattering experiments revealed that RS4 nanoparticles measuring a PdI of 0.380 and an average size of approximately 300 nm, which was very close to the predicted z-average diameter (303.6 nm). The absolute value of zeta potential of RS4 nanoparticles (39.7 mV) was higher than RS4 (32.4 mV), with strengthened swelling power. X-ray diffraction results revealed that homogenization induced a disruption in crystalline structure of RS4 nanoparticles led to amorphous or low-crystallinity. Results of stability analysis showed that RS4 nanosuspensions (particle size) had good stability at 30 °C over 24 h.

Total ozone column derived from GOME and SCIAMACHY using KNMI retrieval algorithms: Validation against Brewer measurements at the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Antón, M.; Kroon, M.; López, M.; Vilaplana, J. M.; Bañón, M.; van der A, R.; Veefkind, J. P.; Stammes, P.; Alados-Arboledas, L.

2011-11-01

This article focuses on the validation of the total ozone column (TOC) data set acquired by the Global Ozone Monitoring Experiment (GOME) and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) satellite remote sensing instruments using the Total Ozone Retrieval Scheme for the GOME Instrument Based on the Ozone Monitoring Instrument (TOGOMI) and Total Ozone Retrieval Scheme for the SCIAMACHY Instrument Based on the Ozone Monitoring Instrument (TOSOMI) retrieval algorithms developed by the Royal Netherlands Meteorological Institute. In this analysis, spatially colocated, daily averaged ground-based observations performed by five well-calibrated Brewer spectrophotometers at the Iberian Peninsula are used. The period of study runs from January 2004 to December 2009. The agreement between satellite and ground-based TOC data is excellent (R2 higher than 0.94). Nevertheless, the TOC data derived from both satellite instruments underestimate the ground-based data. On average, this underestimation is 1.1% for GOME and 1.3% for SCIAMACHY. The SCIAMACHY-Brewer TOC differences show a significant solar zenith angle (SZA) dependence which causes a systematic seasonal dependence. By contrast, GOME-Brewer TOC differences show no significant SZA dependence and hence no seasonality although processed with exactly the same algorithm. The satellite-Brewer TOC differences for the two satellite instruments show a clear and similar dependence on the viewing zenith angle under cloudy conditions. In addition, both the GOME-Brewer and SCIAMACHY-Brewer TOC differences reveal a very similar behavior with respect to the satellite cloud properties, being cloud fraction and cloud top pressure, which originate from the same cloud algorithm (Fast Retrieval Scheme for Clouds from the Oxygen A-Band (FRESCO+)) in both the TOSOMI and TOGOMI retrieval algorithms.

Long-term changes in ozone mini-hole event frequency over the Northern Hemisphere derived from ground-based measurements

NASA Astrophysics Data System (ADS)

Krzycin, Janusz W.

2002-10-01

Decadal changes of ozone mini-hole event appearance over the Northern Hemisphere midlatitudes are examined based on daily total ozone data from seven stations having long records (four decades or more) of ozone observations. The various threshold methods for accepting and rejecting the ozone minima as mini-holes are examined. Mini-hole event activity is seen to be rather stable when averaged over a decadal time scale if the mini-holes are selected as large negative departures (exceeding 20%) relative to the moving long-term total ozone reference. The results are compared with a previous ozone mini-hole climatology derived from satellite data (TOMS measurements on board the Nimbus-7 satellite for the period 1978-93). A nonlinear statistical model (MARS), which takes into account various total ozone dynamical proxies (from NCEP-NCAR reanalysis), is used to study dynamical factors responsible for the ozone extremes over Arosa in the period 1950-99. The model explains as much as 95% of the total variance of the ozone extremes. The model-observation differences averaged over the decadal intervals are rather smooth throughout the whole period analysed. It is suggested that the short-term dynamical processes controlling the appearance of ozone extremes influenced the ozone field in a similar way before and after the onset of abrupt ozone depletion in the early 1980s. The analysis of the ozone profile and the tropopause pressure (from the ozonesondings over Hohenpeissenberg, 1966-99) during mini-hole events shows 60% ozone reduction in the lower stratosphere and an approximately 50 hPa upward shift of the thermal tropopause there.

Large-scale variations in observed Antarctic Sea ice extent and associated atmospheric circulation

NASA Technical Reports Server (NTRS)

Cavalieri, D. J.; Parkinson, C. L.

1981-01-01

The 1974 Antarctic large scale sea ice extent is studied from data from Nimbus 2 and 5 and temperature and sea level pressure fields from the Australian Meteorological Data Set. Electrically Scanning Microwave Radiometer data were three-day averaged and compared with 1000 mbar atmospheric pressure and sea level pressure data, also in three-day averages. Each three-day period was subjected to a Fourier analysis and included the mean latitude of the ice extent and the phases and percent variances in terms of the first six Fourier harmonics. Centers of low pressure were found to be generally east of regions which displayed rapid ice growth, and winds acted to extend the ice equatorward. An atmospheric response was also noted as caused by the changing ice cover.

Total donor ischemic time: relationship to early hemodynamics and intensive care morbidity in pediatric cardiac transplant recipients.

PubMed

Rodrigues, Warren; Carr, Michelle; Ridout, Deborah; Carter, Katherine; Hulme, Sara Louise; Simmonds, Jacob; Elliott, Martin; Hoskote, Aparna; Burch, Michael; Brown, Kate L

2011-11-01

Single-center studies have failed to link modest increases in total donor ischemic time to mortality after pediatric orthotopic heart transplant. We aimed to investigate whether prolonged total donor ischemic time is linked to pediatric intensive care morbidity after orthotopic heart transplant. Retrospective cohort review. Tertiary pediatric transplant center in the United Kingdom. Ninety-three pediatric orthotopic heart transplants between 2002 and 2006. Total donor ischemic time was investigated for association with early post-orthotopic heart transplant hemodynamics and intensive care unit morbidities. Of 43 males and 50 females with median age 7.2 (interquartile range 2.2, 13.0) yrs, 62 (68%) had dilated cardiomyopathy, 20 (22%) had congenital heart disease, and nine (10%) had restrictive cardiomyopathy. The mean total donor ischemic time was 225.9 (sd 65.6) mins. In the first 24 hrs after orthotopic heart transplant, age-adjusted mean arterial blood pressure increased (p < .001), mean pulmonary arterial pressure fell (p = .012), but central venous pressure (p = .58) and left atrial pressure (p = .20) were unchanged. After adjustment for age, primary diagnosis, pre-orthotopic heart transplant mechanical support, and marginal donor factors, longer total donor ischemic time was significantly associated with lower mean arterial blood pressure (p < .001) in the first 24 hrs after orthotopic heart transplant, longer post-orthotopic heart transplant mechanical ventilation (p = .03), longer post-orthotopic heart transplant stay in the intensive care unit (p = .004), and longer post-orthotopic heart transplant stay in hospital (p = .02). Total donor ischemic time was not related to levels of mean pulmonary arterial pressure (p = .62), left atrial pressure (p = .38), or central venous pressure (p = .76) early after orthotopic heart transplant. Prolonged total donor ischemic time has an adverse effect on the donor organ, contributing to lower mean arterial blood pressure, as well as more prolonged ventilation and intensive care unit and hospital stays post-orthotopic heart transplant, reflecting increased morbidity.

Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars.

PubMed

Mickol, R L; Kral, T A

2017-12-01

The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species (Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars

NASA Astrophysics Data System (ADS)

Mickol, R. L.; Kral, T. A.

2017-12-01

The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species ( Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

North Atlantic Basin Tropical Cyclone Activity in Relation to Temperature and Decadal- Length Oscillation Patterns

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2009-01-01

Yearly frequencies of North Atlantic basin tropical cyclones, their locations of origin, peak wind speeds, average peak wind speeds, lowest pressures, and average lowest pressures for the interval 1950-2008 are examined. The effects of El Nino and La Nina on the tropical cyclone parametric values are investigated. Yearly and 10-year moving average (10-yma) values of tropical cyclone parameters are compared against those of temperature and decadal-length oscillation, employing both linear and bi-variate analysis, and first differences in the 10-yma are determined. Discussion of the 2009 North Atlantic basin hurricane season, updating earlier results, is given.

Parents' Reactions to Finding Out That Their Children Have Average or above Average IQ Scores.

ERIC Educational Resources Information Center

Dirks, Jean; And Others

1983-01-01

Parents of 41 children who had been given an individually-administered intelligence test were contacted 19 months after testing. Parents of average IQ children were less accurate in their memory of test results. Children with above average IQ experienced extremely low frequencies of sibling rivalry, conceit or pressure. (Author/HLM)

40 CFR Table 2 to Subpart Jjjjj of... - Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Kiln equipped with a WS a. Maintain the average scrubber pressure drop for each 3-hour block period at... average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test; and c. Maintain the average scrubber liquid flow rate for each 3-hour...

40 CFR Table 2 to Subpart Jjjjj of... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Kiln equipped with a WS a. Maintain the average scrubber pressure drop for each 3-hour block period at... average scrubber liquid pH for each 3-hour block period at or above the average scrubber liquid pH established during the performance test; and c. Maintain the average scrubber liquid flow rate for each 3-hour...

Coupled-Flow Simulation of HP-LP Turbines Has Resulted in Significant Fuel Savings

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

2001-01-01

Our objective was to create a high-fidelity Navier-Stokes computer simulation of the flow through the turbines of a modern high-bypass-ratio turbofan engine. The simulation would have to capture the aerodynamic interactions between closely coupled high- and low-pressure turbines. A computer simulation of the flow in the GE90 turbofan engine's high-pressure (HP) and low-pressure (LP) turbines was created at GE Aircraft Engines under contract with the NASA Glenn Research Center. The three-dimensional steady-state computer simulation was performed using Glenn's average-passage approach named APNASA. The areas upstream and downstream of each blade row mutually interact with each other during engine operation. The embedded blade row operating conditions are modeled since the average passage equations in APNASA actively include the effects of the adjacent blade rows. The turbine airfoils, platforms, and casing are actively cooled by compressor bleed air. Hot gas leaks around the tips of rotors through labyrinth seals. The flow exiting the high work HP turbines is partially transonic and, therefore, has a strong shock system in the transition region. The simulation was done using 121 processors of a Silicon Graphics Origin 2000 (NAS 02K) cluster at the NASA Ames Research Center, with a parallel efficiency of 87 percent in 15 hr. The typical average-passage analysis mesh size per blade row was 280 by 45 by 55, or approx.700,000 grid points. The total number of blade rows was 18 for a combined HP and LP turbine system including the struts in the transition duct and exit guide vane, which contain 12.6 million grid points. Design cycle turnaround time requirements ran typically from 24 to 48 hr of wall clock time. The number of iterations for convergence was 10,000 at 8.03x10(exp -5) sec/iteration/grid point (NAS O2K). Parallel processing by up to 40 processors is required to meet the design cycle time constraints. This is the first-ever flow simulation of an HP and LP turbine. In addition, it includes the struts in the transition duct and exit guide vanes.

Unsteady Loss in the Stator Due to the Incoming Rotor Wake in a Highly-Loaded Transonic Compressor

NASA Technical Reports Server (NTRS)

Hah, Chunill

2015-01-01

The present paper reports an investigation of unsteady loss generation in the stator due to the incoming rotor wake in an advanced GE transonic compressor design with a high-fidelity numerical method. This advanced compressor with high reaction and high stage loading has been investigated both experimentally and analytically in the past. The measured efficiency in this advanced compressor is significantly lower than the design intention/goal. The general understanding is that the current generation of compressor design/analysis tools miss some important flow physics in this modern compressor design. To pinpoint the source of the efficiency miss, an advanced test with a detailed flow traverse was performed for the front one and a half stage at the NASA Glenn Research Center. Detailed data-match analysis by GE identified an unexpected high loss generation in the pressure side of the stator passage. Higher total temperature and lower total pressure are measured near the pressure side of the stator. Various analyses based on the RANS and URANS of the compressor stage do not calculate the measured higher total temperature and lower total pressure on the pressure side of the stator. In the present paper, a Large Eddy Simulation (LES) is applied to find the fundamental mechanism of this unsteady loss generation in the stator due to the incoming rotor wake. The results from the LES were first compared with the NASA test results and the GE interpretation of the test data. LES calculates lower total pressure and higher total temperature on the pressure side of the stator, as the measured data showed, resulting in large loss generation on the pressure side of the stator. Detailed examination of the unsteady flow field from LES shows that the rotor wake, which has higher total temperature and higher total pressure relative to the free stream, interacts quite differently with the pressure side of the blade compared to the suction side of the blade. The higher temperature in the wake remains high as the wake passes through the pressure side of the blade. On the other hand, the total temperature diffuses as it passes through near the suction surface. For the presently investigated compressor, the classical intra-stator wake transport to the pressure side of the blade by the slip velocity in the wake seems to be minor. The main causes of this phenomenon are three-dimensional unsteady vortex interactions near the blade surface. The stabilizing effect of the concave curvature on the suction side keeps the rotor wake thin. On the other hand, the destabilizing effect of the convex curvature of the pressure side makes the rotor wake thicker, which results in a higher total temperature measurement at the stator exit. Additionally, wake stretching through the stator seems to contribute to the redistribution of the total temperature and the loss generation.

Excessive variability in systolic blood pressure that is self-measured at home exacerbates the progression of brain white matter lesions and cognitive impairment in the oldest old.

PubMed

Liu, Zhendong; Zhao, Yingxin; Zhang, Hua; Chai, Qiang; Cui, Yi; Diao, Yutao; Xiu, Jianchao; Sun, Xiaolin; Jiang, Guosheng

2016-04-01

To investigate the effects of variability in self-measured systolic blood pressure at home on the progression of cognitive impairment and white matter lesions in the oldest old. Between April 2009 and October 2009, 248 oldest old aged 80 years or older were eligibly enrolled from geriatric practices and community-dwelling areas of Shandong, China. Self-measured blood pressure at home (HBP) was measured for 7 consecutive days at the baseline, and the Mini-Mental State Examination (MMSE) score and brain white matter hyperintensities (WMH) were assessed at the baseline and during the final follow-up visit. Variability in systolic HBP was evaluated using coefficient of variation (CV) in serial daily systolic HBP measurements of the last 6 consecutive days. After an average of 2.3 years of follow-up visits, 232 oldest old were included in and 16 were excluded from the analysis. The MMSE score declined -4.76 (interquartile ranges: -10.71, -0.83) %, the periventricular WMH, deep WMH, total WMH and WMH fraction increased 16.46 (s.d.: 6.72)%, 10.05 (s.d.: 6.40)%, 14.69 (s.d.: 6.07)% and 15.95 (s.d.: 6.32)%, respectively, in the total oldest old. A declined percentage of the MMSE score and increased percentages of the periventricular WMH, deep WMH, total WMH and WMH fraction in the high group divided by tertile of the CV of the systolic HBP at baseline were greater than those in the low group (P<0.05). The significant differences were retained after adjusting for covariates, including the MMSE score, periventricular WMH, deep WMH and WMH fraction at the baseline (P<0.05). Excessive variability in self-measured systolic HBP exacerbates the progression of cognitive impairment and brain white matter lesions in the oldest old.

Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy.

PubMed

Wells, Ellen M; Herbstman, Julie B; Lin, Yu Hong; Hibbeln, Joseph R; Halden, Rolf U; Witter, Frank R; Goldman, Lynn R

2017-04-01

Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury. This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labor and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighborhood income, parity, smoking, n-3 fatty acids and selenium. Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure. We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Model aerodynamic test results for two variable cycle engine coannular exhaust systems at simulated takeoff and cruise conditions. Comprehensive data report. Volume 3: Graphical data book 1

NASA Technical Reports Server (NTRS)

Nelson, D. P.

1981-01-01

A graphical presentation of the aerodynamic data acquired during coannular nozzle performance wind tunnel tests is given. The graphical data consist of plots of nozzle gross thrust coefficient, fan nozzle discharge coefficient, and primary nozzle discharge coefficient. Normalized model component static pressure distributions are presented as a function of primary total pressure, fan total pressure, and ambient static pressure for selected operating conditions. In addition, the supersonic cruise configuration data include plots of nozzle efficiency and secondary-to-fan total pressure pumping characteristics. Supersonic and subsonic cruise data are given.