A study of muscular tissue of animal origin by reflection-spectroscopy methods

NASA Astrophysics Data System (ADS)

Plotnikova, L. V.; Nechiporenko, A. P.; Orekhova, S. M.; Plotnikov, P. P.; Ishevskii, A. L.

2017-06-01

A comparative analysis of the spectral characteristics of the surface of muscular tissue of animal origin (pork) and its main components has been performed by the methods of diffuse reflection electronic spectroscopy (DRES) and frustrated total internal reflection IR spectroscopy. The experiments have shown that the application of the DRES method makes it possible to detect more pronounced changes in the surface optical characteristics of muscular tissue and obtain electronic spectra containing information about the component composition of its main parts under successive extraction of sarcoplasmic materials, myofibrillar proteins of the actomyosin complex, and stroma mucopolysaccharides.

Bionic Design, Materials and Performance of Bone Tissue Scaffolds

PubMed Central

Wu, Tong; Yu, Suihuai; Chen, Dengkai; Wang, Yanen

2017-01-01

Design, materials, and performance are important factors in the research of bone tissue scaffolds. This work briefly describes the bone scaffolds and their anatomic structure, as well as their biological and mechanical characteristics. Furthermore, we reviewed the characteristics of metal materials, inorganic materials, organic polymer materials, and composite materials. The importance of the bionic design in preoperative diagnosis models and customized bone scaffolds was also discussed, addressing both the bionic structure design (macro and micro structure) and the bionic performance design (mechanical performance and biological performance). Materials and performance are the two main problems in the development of customized bone scaffolds. Bionic design is an effective way to solve these problems, which could improve the clinical application of bone scaffolds, by creating a balance between mechanical performance and biological performance. PMID:29039749

Bionic Design, Materials and Performance of Bone Tissue Scaffolds.

PubMed

Wu, Tong; Yu, Suihuai; Chen, Dengkai; Wang, Yanen

2017-10-17

Design, materials, and performance are important factors in the research of bone tissue scaffolds. This work briefly describes the bone scaffolds and their anatomic structure, as well as their biological and mechanical characteristics. Furthermore, we reviewed the characteristics of metal materials, inorganic materials, organic polymer materials, and composite materials. The importance of the bionic design in preoperative diagnosis models and customized bone scaffolds was also discussed, addressing both the bionic structure design (macro and micro structure) and the bionic performance design (mechanical performance and biological performance). Materials and performance are the two main problems in the development of customized bone scaffolds. Bionic design is an effective way to solve these problems, which could improve the clinical application of bone scaffolds, by creating a balance between mechanical performance and biological performance.

Development of a graphical method for choosing the optimal mode of traffic light

NASA Astrophysics Data System (ADS)

Novikov, A. N.; Katunin, A. A.; Novikov, I. A.; Kravchenko, A. A.; Shevtsova, A. G.

2018-05-01

Changing the transportation infrastructure for improving the main characteristics of the transportation flow is the key problem in transportation planning, therefore the main question lies in the ability to plan the change of the main indicators for the long term. In this investigation, an analysis of the city’s population has been performed and the most difficult transportation segment has been identified. During its identification, the main characteristics of the transportation flow have been established. For the evaluation of these characteristics until 2025, an analysis of the available methods of establishing changes in their values has been conducted. During the analysis of the above mentioned methods of evaluation of the change in intensity, based on the method of extrapolation, three scenarios of the development of the transportation system have been identified. It has been established that the most favorable method of controlling the transportation flow in the entrance to the city is the long term control of the traffic system. For the first time, with the help of the authors, based on the investigations of foreign scientists and the mathematical analysis of the changes in intensiveness on the main routes of the given road, the method of graphically choosing the required control plan has been put forward. The effectiveness of said organization scheme of the transportation system has been rated in the Transyt-14 program, with the analysis of changes in the main characteristics of the transportation flow.

Raman Laser Spectrometer Development for ExoMars

NASA Astrophysics Data System (ADS)

Pérez, C.; Colombo, M.; Díaz, C.; Santamaría, P.; Ingley, R.; Parrot, Y.; Maurice, S.; Popp, J.; Tarcea, N.; Edwards, H. G. M.

2013-09-01

The Raman Laser Spectrometer is one of the Pasteur Payload instruments, within the ESA's ExoMars mission. The aim of the work presented here is to provide a summary of the instrument design and performances. For that the instrument current characteristics and performances, and its technological ass assessment program main results are presented and discussed.

Human Performance on the Traveling Salesman and Related Problems: A Review

ERIC Educational Resources Information Center

MacGregor, James N.; Chu, Yun

2011-01-01

The article provides a review of recent research on human performance on the traveling salesman problem (TSP) and related combinatorial optimization problems. We discuss what combinatorial optimization problems are, why they are important, and why they may be of interest to cognitive scientists. We next describe the main characteristics of human…

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety, performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key Criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket-engines characteristics. This includes BME impacts on vehicle system weight, performance, design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

A flight investigation of basic performance characteristics of a teetering-rotor attack helicopter

NASA Technical Reports Server (NTRS)

Morris, C. E. K., Jr.

1979-01-01

Flight data were obtained with an instrumented AH-16 helicopter having uninstrumented, standard main-rotor blades. The data are presented to facilitate the analysis of data taken when the same vehicle was flown with instrumented main-rotor blades built with new airfoils. Test results include data on performance, flight-state parameters, pitch-link loads and blade angles for level flight, descending turns and pull-ups. Flight test procedures and the effects of both trim variations and transient phenomena on the data are discussed.

Extravehicular activities guidelines and design criteria

NASA Technical Reports Server (NTRS)

Brown, N. E.; Dashner, T. R.; Hayes, B. C.

1973-01-01

A listing of astronaut EVA support systems and equipment, and the physical, operational, and performance characteristics of each major system are presented. An overview of the major ground based support operations necessary in the development and verification of orbital EVA systems is included. The performance and biomedical characteristics of man in the orbital EV environment are discussed. Major factors affecting astronaut EV work performance are identified and delineated as they relate to EV support systems design. Data concerning the medical and physiological aspects of spaceflight on man are included. The document concludes with an extensive bibliography, and a series of appendices which expand on some of the information presented in the main body.

Assessment of railway wagon suspension characteristics

NASA Astrophysics Data System (ADS)

Soukup, Josef; Skočilas, Jan; Skočilasová, Blanka

2017-05-01

The article deals with assessment of railway wagon suspension characteristics. The essential characteristics of a suspension are represented by the stiffness constants of the equivalent springs and the eigen frequencies of the oscillating movements in reference to the main central inertia axes of a vehicle. The premise of the experimental determination of these characteristic is the knowledge of the gravity center position and the knowledge of the main central inertia moments of the vehicle frame. The vehicle frame performs the general spatial movement when the vehicle moves. An analysis of the frame movement generally arises from Euler's equations which are commonly used for the description of the spherical movement. This solution is difficult and it can be simplified by applying the specific assumptions. The eigen frequencies solutions and solutions of the suspension stiffness are presented in the article. The solutions are applied on the railway and road vehicles with the simplifying conditions. A new method which assessed the characteristics is described in the article.

Relationships between actual and desired workplace characteristics and job satisfaction for community health workers in China: a cross-sectional study.

PubMed

Li, Li; Zhang, Zhong; Sun, Zhinan; Zhou, Hao; Liu, Xinyan; Li, Heng; Fan, Lihua; Coyte, Peter C

2014-11-18

Community health workers are the main providers of community health services in China and have been important in the process of health system reform that has been in place since 2009. Therefore, it is critical that healthcare managers and policy decision makers motivate current staff and improve their job satisfaction. This study examined workplace characteristics and their contribution to job satisfaction in community health workers in Heilongjiang Province, China. A cross-sectional survey of 448 community health workers, from three cities in Heilongjiang province, was conducted between October 1, 2012 and December 31, 2012. Multistage sampling procedures were used to measure socioeconomic and demographic status, job satisfaction, and both actual and desired workplace characteristics. Factor analysis was conducted to determine the main factors contributing to workplace characteristics, and multiple linear regression analysis was performed to assess the key determinants of job satisfaction. Eight groups of factors were identified as the most important workplace characteristics. These comprised system and policy; fringe benefits; work itself; work relationships; professional development; recognition; work environment; and remuneration. In all cases, all desired workplace characteristics were higher than the associated actual workplace characteristics. The main determinants of job satisfaction were occupation, years worked in health service institution, and five subscales representing the gap between desired and actual workplace characteristics, which were system and policy; fringe benefits; working relationship; professional development; and remuneration. These findings suggested that managers wishing to enhance job satisfaction should assess workplace characteristics comprehensively and design mechanisms that reduce the gap between actual and desired workplace characteristics.

The effect of helicopter main rotor blade phasing and spacing on performance, blade loads, and acoustics

NASA Technical Reports Server (NTRS)

Gangwani, S. T.

1976-01-01

The performance, blade loads, and acoustic characteristics of a variable geometry rotor (VGR) system in forward flight and in a pullup maneuver were determined by the use of existing analytical programs. The investigation considered the independent effects of vertical separation of two three-bladed rotor systems as well as the effects of azimuthal spacing between the blades of the two rotors. The computations were done to determine the effects of these parameters on the performance, blade loads, and acoustic characteristics at two advance ratios in steady-state level flight and for two different g pullups at one advance ratio. To evaluate the potential benefits of the VGR concept in forward flight and pullup maneuvers, the results were compared as to performance, oscillatory blade loadings, vibratory forces transmitted to the fixed fuselage, and the rotor noise characteristics of the various VGR configurations with those of the conventional six-bladed rotor system.

Space shuttle requirements/configuration evolution

NASA Technical Reports Server (NTRS)

Andrews, E. P.

1991-01-01

Space Shuttle chronology; Space Shuttle comparison; Cost comparison; Performance; Program ground rules; Sizing criteria; Crew/passenger provisions; Space Shuttle Main Engine (SSME) characteristics; Space Shuttle program milestones; and Space Shuttle requirements are outlined. This presentation is represented by viewgraphs.

Determination of Functional Capabilities, the Level of Physical Performance and the State of Main Physiological Body Systems in the First Hours after the Accomplishment of Long-term Space Flights ("Field Test")

NASA Technical Reports Server (NTRS)

Kozlovskaya, Inesa; Tomilovskaya, Elena; Rukavishnikov, Ilya; Kitov, Vladimir; Reschke, Millard; Kofman, Igor

2014-01-01

Long-term stay in weightlessness is accompanied by alterations in the activity of main physiological body systems including sensory-motor, skeletal-muscular disturbances and cardiovascular deconditioning. However, up to now, there are no data on the state and level of functional performance of cosmonauts/astronauts directly after flight, nor are there data to help define the dynamic recovery of functional characteristics and work efficiency which are greatly needed to provide the safety and planning of their activity once they reach space objects. The Russian and American scientists are currently engaged in a joint experiment known as the "Field Test" with the goal of studying the functional performance and the state of main physiological body systems directly after landing and their temporal recovery dynamics. The functional performance is identified during the test by temporal characteristics of the movements of spatial translation, the stability of the vertical stance for 3.5 min, and the kinematic characteristics of walking - non-complicated and complicated. The following characteristics are identified as physiological characteristics of the test: a) orthostatic tolerance during stand test, b) back muscle tone; c) vertical stability - by characteristics of the correction responses to unexpected perturbations of the vertical stance, and d) support reactions during the performance of the full battery of tests. To date, a pilot version of the "Field Test" has been conducted with participation from four Russian cosmonauts. The results of studies have shown that in 1 - 5 hours after landing the functional abilities of the cosmonauts are considerably reduced. All the test movements at this time are considerably slower than preflight and the more complicated the task is, the greater significant reduction in orthostatic tolerance: during the first test that occurs 1 - 5 hours after landing. two of four cosmonauts declined to continue the task after the orthostatic test (one of them did not wear the anti-G suit "Centaurus" during testing). Blood pressure during moving out of prone posture to vertical stance in one of the cosmonauts and of sitting to standing position in the other dropped to the precollapse level. The results of the studies have confirmed the feasibility, the usefulness and the safety of conducting tests as close as possible to the landing. The program of "Field Test" experiment will be continued and extended.

Illustrating Performance Indicators and Course Characteristics to Support Students' Self-Regulated Learning in CS1

ERIC Educational Resources Information Center

Ott, Claudia; Robins, Anthony; Haden, Patricia; Shephard, Kerry

2015-01-01

In higher education, quality feedback for students is regarded as one of the main contributors to improve student learning. Feedback to support students' development into self-regulated learners, who set their own goals, self-monitor their actual performance according to these goals, and adjust learning strategies if necessary, is seen as an…

Electronics materials research

NASA Technical Reports Server (NTRS)

1982-01-01

The electronic materials and is aimed at the establishment of quantitative relationships underlying crystal growth parameters, materials properties, electronic characteristics and device applications. The overall program evolves about the following main thrust areas: (1) crystal growth novel approaches to engineering of semiconductor materials; (2) investigation of materials properties and electronic characteristics on a macro and microscale; (3) surface properties and surface interactions with the bulk and ambients; (4) electronic properties controlling device applications and device performance.

Non-intrusive speed sensor. [space shuttle main engine turbopumps

NASA Technical Reports Server (NTRS)

Maram, J.; Wyett, L.

1984-01-01

A computerized literature search was performed to identify candidate technologies for remote, non-intrusive speed sensing applications in Space Shuttle Main Engine (SSME) turbopumps. The three most promising technologies were subjected to experimental evaluation to quantify their performance characteristics under the harsh environmental requirements within the turbopumps. Although the infrared and microwave approaches demonstrated excellent cavitation immunity in laboratory tests, the variable-source magnetic speed sensor emerged as the most viable approach. Preliminary design of this speed sensor encountered no technical obstacles and resulted in viable and feasible speed nut, sensor housing, and sensor coil designs.

A review of hospital characteristics associated with improved performance.

PubMed

Brand, Caroline A; Barker, Anna L; Morello, Renata T; Vitale, Michael R; Evans, Sue M; Scott, Ian A; Stoelwinder, Johannes U; Cameron, Peter A

2012-10-01

The objective of this review was to critically appraise the literature relating to associations between high-level structural and operational hospital characteristics and improved performance. The Cochrane Library, MEDLINE (Ovid), CINAHL, proQuest and PsychINFO were searched for articles published between January 1996 and May 2010. Reference lists of included articles were reviewed and key journals were hand searched for relevant articles. and data extraction Studies were included if they were systematic reviews or meta-analyses, randomized controlled trials, controlled before and after studies or observational studies (cohort and cross-sectional) that were multicentre, comparative performance studies. Two reviewers independently extracted data, assigned grades of evidence according to the Australian National Health and Medical Research Council guidelines and critically appraised the included articles. Data synthesis Fifty-seven studies were reported within 12 systematic reviews and 47 observational articles. There was heterogeneity in use and definition of performance outcomes. Hospital characteristics investigated were environment (incentives, market characteristics), structure (network membership, ownership, teaching status, geographical setting, service size) and operational design (innovativeness, leadership, organizational culture, public reporting and patient safety practices, information technology systems and decision support, service activity and planning, workforce design, staff training and education). The strongest evidence for an association with overall performance was identified for computerized physician order entry systems. Some evidence supported the associations with workforce design, use of financial incentives, nursing leadership and hospital volume. There is limited, mainly low-quality evidence, supporting the associations between hospital characteristics and healthcare performance. Further characteristic-specific systematic reviews are indicated.

Characteristics of the organic fraction of municipal solid waste and methane production: A review.

PubMed

Campuzano, Rosalinda; González-Martínez, Simón

2016-08-01

Anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) is a viable alternative for waste stabilization and energy recovery. Biogas production mainly depends on the type and amount of organic macromolecules. Based on results from different authors analysing OFMSW from different cities, this paper presents the importance of knowing the OFMSW composition to understand how anaerobic digestion can be used to produce methane. This analysis describes and discusses physical, chemical and bromatological characteristics of OFMSW reported by several authors from different countries and cities and their relationship to methane production. The main conclusion is that the differences are country and not city dependant. Cultural habits and OFMSW management systems do not allow a generalisation but the individual analysis for specific cities allow understanding the general characteristics for a better methane production. Not only are the OFMSW characteristics important but also the conditions under which the methane production tests were performed. Copyright © 2016. Published by Elsevier Ltd.

Water Resources Investigation. St. Louis Metropolitan Area, Missouri and Illinois. Maline Creek, Missouri Survey Report. Volume 1. Main Report.

DTIC Science & Technology

1980-09-01

ILLINOIS MALINE CREEK, MISSOURI SURVEY REPORT 00 C); 7 - ELECTE MADISON,~’ MAY 3 %8 CONT S D ’ a RAKI CUT MAIN REPORT - %" DEPARTMENT OF THE ARMY ST...Investigation St. Louis Metropolitan Area, S. PERFORMING ORG. REPORT NUMBER y~~> Missouri and Illinois Vol One, Main Report 7 .AUTNOR(s) 8 OTATO RN UBRq S...characteristics thereby significantly improving the area’s plant, animal, fish and fowl habitats while also improving the human habitation

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket engines' characteristics. This includes BME impacts on vehicle system weight, perfortnance,design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

Development of an analytical method to predict helicopter main rotor performance in icing conditions

NASA Technical Reports Server (NTRS)

Britton, Randall K.

1992-01-01

Historically, certification of a helicopter for flight into known icing conditions was a problem. This is because of the current emphasis on flight testing for verification of system performance. Flight testing in icing conditions is difficult because, in addition to being dangerous and expensive, many times conditions which are sought after cannot be readily found in nature. The problem is compounded for helicopters because of their small range in comparison to many fixed wing aircraft. Thus, helicopters are forced to wait for conditions to occur in a certain region rather than seeking them out. These and other drawbacks to flight testing prompted extreme interest in developing validated alternatives to flight testing. One such alternative is theoretical prediction. It is desirable to have the ability to predict how a helicopter will perform when subjected to icing conditions. Herein, calculations are restricted to the main rotor, and are illustrated. The computational tool used to obtain performance is the lifting line analysis of B65. B65 incorporates experimental data into data banks in order to determine the section lift, drag, and moment characteristics of various airfoils at different Mach numbers and angles of attack. The local flow angle is calculated at user specified radial locations. This flow angle, along with the local Mach number is then cross referenced with the airfoil tables to obtain the local section characteristics. The local characteristics are then integrated together to obtain the entire rotor attributes. Once the clean performance is known, characterization of the type and shape of ice which accretes on the rotor blades is obtained using the analysis of LEWICE. The Interactive Boundary Layer (IBL) method then calculates the 2-D characteristics of the iced airfoil for input into the airfoil data bank of B65. Calculations are restricted to natural ice shedding and it is assumed that no de-icing takes place. Once the new lift, drag, and moment characteristics are known for the entire blade radius, this information is fed into B65, where the iced performance is then calculated.

Music psychopathology. V. Objective features of instrumental performance and psychopathology.

PubMed

Steinberg, R; Fani, M; Raith, L

1992-01-01

Mental disease systematically impairs musical expression according to nosologic classification. This was demonstrated with a polarity profile of the instrumental performances of 60 inpatients and 14 controls matched for musical aptitude. Objective performance characteristics such as irregularities and playing faults were analyzed too. No meaningful correlation between these features and psychopathology resulted. This indicates that even in severe psychopathologic alterations performance features, which depend mainly on education and actual training, are not altered in a systematic manner, in contrast to expressive qualities.

Study on kinematic and compliance test of suspension

NASA Astrophysics Data System (ADS)

Jing, Lixin; Wu, Liguang; Li, Xuepeng; Zhang, Yu

2017-09-01

Chassis performance development is a major difficulty in vehicle research and development, which is the main factor restricting the independent development of vehicles in China. These years, through a large number of studies, chassis engineers have found that the suspension K&C characteristics as a quasi-static characteristic of the suspension provides a technical route for the suspension performance R&D, and the suspension K&C test has become an important means of vehicle benchmarking, optimization and verification. However, the research on suspension K&C test is less in china, and the test conditions and setting requirements vary greatly from OEM to OEM. In this paper, the influence of different settings on the characteristics of the suspension is obtained through experiments, and the causes of the differences are analyzed; in order to fully reflect the suspension characteristics, the author recommends the appropriate test case and settings.

Relationship of goat milk flow emission variables with milking routine, milking parameters, milking machine characteristics and goat physiology.

PubMed

Romero, G; Panzalis, R; Ruegg, P

2017-11-01

The aim of this paper was to study the relationship between milk flow emission variables recorded during milking of dairy goats with variables related to milking routine, goat physiology, milking parameters and milking machine characteristics, to determine the variables affecting milking performance and help the goat industry pinpoint farm and milking practices that improve milking performance. In total, 19 farms were visited once during the evening milking. Milking parameters (vacuum level (VL), pulsation ratio and pulsation rate, vacuum drop), milk emission flow variables (milking time, milk yield, maximum milk flow (MMF), average milk flow (AVMF), time until 500 g/min milk flow is established (TS500)), doe characteristics of 8 to 10 goats/farm (breed, days in milk and parity), milking practices (overmilking, overstripping, pre-lag time) and milking machine characteristics (line height, presence of claw) were recorded on every farm. The relationships between recorded variables and farm were analysed by a one-way ANOVA analysis. The relationships of milk yield, MMF, milking time and TS500 with goat physiology, milking routine, milking parameters and milking machine design were analysed using a linear mixed model, considering the farm as the random effect. Farm was significant (P<0.05) in all the studied variables. Milk emission flow variables were similar to those recommended in scientific studies. Milking parameters were adequate in most of the farms, being similar to those recommended in scientific studies. Few milking parameters and milking machine characteristics affected the tested variables: average vacuum level only showed tendency on MMF, and milk pipeline height on TS500. Milk yield (MY) was mainly affected by parity, as the interaction of days in milk with parity was also significant. Milking time was mainly affected by milk yield and breed. Also significant were parity, the interaction of days in milk with parity and overstripping, whereas overmilking showed a slight tendency. We concluded that most of the studied variables were mainly related to goat physiology characteristics, as the effects of milking parameters and milking machine characteristics were scarce.

Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America*

PubMed Central

Corrêa, Marcelo de Paula

2015-01-01

The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures. PMID:26131858

Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America.

PubMed

Corrêa, Marcelo de Paula

2015-01-01

The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures.

How joint characteristics between a piezoelectric beam and the main structure affect the performance of an energy harvester

NASA Astrophysics Data System (ADS)

Jahani, K.; Rafiei, M. M.; Aghazadeh, P.

2017-09-01

In this paper, the influence of the joint region between a piezoelectric energy harvesting beam and the vibratory main structure is studied. The investigations are conducted in two separate sections, namely numerical and experimental studies. In numerical studies, the effects of nonlinear parameters on generated power are investigated while the joint characteristics the between vibrating base and a piezoelectric energy harvester are taken into consideration. A unimorph beam with a tip mass and a nonlinear piezoelectric layer that undergoes a large-amplitude deflection is considered as an energy harvester. By applying the Euler-Lagrange equation and Gauss’s law the mechanical and electrical equations of motion are obtained, respectively. The excitation frequency is assumed to be close to the first natural frequency. Thus, a unimodal response is considered to be like that of a system with a single degree of freedom (SDOF). The joint between the vibrating main structure and the cantilevered beam is then added to the SDOF model. The joint characteristics are simulated with a light mass, mj , linear spring stiffness, kj , and equivalent viscous damper, cj . In two scenarios, i.e. with a rigid joint and with a flexible one, a numerical approach is followed to investigate the effects of each nonlinear parameter of the harvester (stiffness, damping and piezoelectric coefficient) on the harvested power. In experimental studies, the influence of a bolted joining technique and a flexible adhesive bonding method on the harvested power is investigated. The results achieved experimentally confirm those obtained numerically, i.e. a stiffer joint leads to a greater power produced by the harvester. In other words, neglecting the joint characteristics will cause the performance (maximum output power and the range of excitation frequency) of the harvester to be overestimated in numerical simulations.

Athlete Characteristics and Team Competitive Performance as Moderators for the Relationship Between Coach Transformational Leadership and Athlete Performance.

PubMed

Bormann, Kai C; Schulte-Coerne, Paul; Diebig, Mathias; Rowold, Jens

2016-06-01

The goal of this study is to examine the effects of coaches' transformational leadership on player performance. To advance existing research, we examine (a) effects on individual and team performance and (b) consider joint moderating effects of players' win orientation and teams' competitive performance on the leadership- individual performance link. In a three-source sample from German handball teams, we collected data on 336 players and 30 coaches and teams. Results showed positive main effects of transformational leadership's facet of articulating a vision (AV) on team and individual performance and negative main effects of providing an appropriate model (PAM) on team performance. With regard to moderating effects, AV increased and PAM decreased individual performance when both moderators were low, and intellectual stimulation had a positive effect when both were high. This study expands insights into the potential and limitation of transformational leadership with a strong focus on the role of situational contingencies.

Characteristics of Infrared Detectors for Spece Applications

DTIC Science & Technology

2000-10-01

using Platinium Resistance Thermometers using the four lead method. The readout is performed by a high performace voltmeter, HP 3458 type. These...3.3.4 Temperature measurements The accuracy of the temperature measurements are mainly due to the Platinium Resistance Thermometers using the four lead

Job Demands-Control-Support model and employee safety performance.

PubMed

Turner, Nick; Stride, Chris B; Carter, Angela J; McCaughey, Deirdre; Carroll, Anthony E

2012-03-01

The aim of this study was to explore whether work characteristics (job demands, job control, social support) comprising Karasek and Theorell's (1990) Job Demands-Control-Support framework predict employee safety performance (safety compliance and safety participation; Neal and Griffin, 2006). We used cross-sectional data of self-reported work characteristics and employee safety performance from 280 healthcare staff (doctors, nurses, and administrative staff) from Emergency Departments of seven hospitals in the United Kingdom. We analyzed these data using a structural equation model that simultaneously regressed safety compliance and safety participation on the main effects of each of the aforementioned work characteristics, their two-way interactions, and the three-way interaction among them, while controlling for demographic, occupational, and organizational characteristics. Social support was positively related to safety compliance, and both job control and the two-way interaction between job control and social support were positively related to safety participation. How work design is related to employee safety performance remains an important area for research and provides insight into how organizations can improve workplace safety. The current findings emphasize the importance of the co-worker in promoting both safety compliance and safety participation. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Note: An improved solenoid driver valve for miniature shock tubes.

PubMed

Lynch, P T

2016-05-01

A solenoid driver valve has been built to improve the operating performance of diaphragmless shock tubes, which are used for high pressure, high temperature chemical kinetics, and fluid mechanics studies. For shock tube driver application, the most important characteristics are those of sealing, strength, and quality of the generated shock waves and repeatability of opening characteristics and therefore subsequent post-shock conditions. The main features of the new driver valve are a face o-ring sealing design of the valve, the large internal volume, and through inserts near the solenoid core: adjustable opening characteristics of the valve.

Performance and Stability Characteristics of a Uni-Element Swirl Injector for Oxygen-Rich Stage Combustion Cycles

NASA Technical Reports Server (NTRS)

Pal, S.; Kalitan, D.; Woodward, R. D.; Santoro, R. J.

2004-01-01

A uni-element liquid propellant combustion performance and instability study for liquid RP-1 and hot oxygen-rich pre-burner products was conducted, at a chamber pressure of about 1000 psi. using flush and recessed swirl injectors. High-frequency pressure transducer measurements were analyzed to yield the characteristic frequencies which were compared to expected frequencies of the chamber. Modes, which were discovered to be present within the main chamber included, the first longitudinal, detected at approximately 1950 Hz, and the second longitudinal mode at approximately 3800 Hz. An additional first longitudinal quarter wave mode was measured at a frequency of approximately 23000 Hz for the recessed swirl injector configuration. The characteristic instabilities resulting from these experiments were relatively weak averaging 0.2% to 0.3% of the chamber pressure.

On the main photoelectric characteristics of three-junction InGaP/InGaAs/Ge solar cells in a broad temperature range (–197°C ≤ T ≤ +85°C)

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

Andreev, V. M.; Malevskiy, D. A.; Pokrovskiy, P. V.

2016-10-15

This study is aimed at investigating the main photoelectric characteristics of three-cascade InGaP/InGaAs/Ge photoelectric converters in a broad temperature range (–197°C ≤ T ≤ +85°C). On account of analysis of photosensitivity spectra and optical current–voltage characteristics, such temperature dependences as the open-circuit voltage (V{sub oc}), filling factor of the current–voltage characteristic (FF), and the photoelectric conversion efficiency of solar radiation are determined. Investigations are performed at illumination intensities corresponding to operation under concentrated radiation. Decreased temperatures facilitate the selection of samples with the minimal “parasitic” potential barriers. The influence of excitationtransfer processes from a cascade into a cascade is estimatedmore » by means of secondary luminescent radiation. The highest photoelectric conversion efficiency of 52% is measured at a concentration multiplicity of 100 “suns” and a temperature of–160°C.« less

Engineering design manual of parachute decelerator characteristics for space shuttle solid rocket booster recovery

NASA Technical Reports Server (NTRS)

Mansfield, D. L.

1973-01-01

The design criteria and characteristics of parachutes for recovery of the solid rocket boosters used with the space shuttle launch are presented. A computer program for analyzing the requirements of the parachute decelerators is described. The computer inputs for both the drogue and main parachute decelerators are; (1) parachute size, (2) deployment conditions, (3) inflation times, (4) reefing times, (5) mass properties, (6) spring properties, and (7) aerodynamic coefficients. Graphs of the parachute performance are included.

Specialized data analysis for the Space Shuttle Main Engine and diagnostic evaluation of advanced propulsion system components

NASA Technical Reports Server (NTRS)

1993-01-01

The Marshall Space Flight Center is responsible for the development and management of advanced launch vehicle propulsion systems, including the Space Shuttle Main Engine (SSME), which is presently operational, and the Space Transportation Main Engine (STME) under development. The SSME's provide high performance within stringent constraints on size, weight, and reliability. Based on operational experience, continuous design improvement is in progress to enhance system durability and reliability. Specialized data analysis and interpretation is required in support of SSME and advanced propulsion system diagnostic evaluations. Comprehensive evaluation of the dynamic measurements obtained from test and flight operations is necessary to provide timely assessment of the vibrational characteristics indicating the operational status of turbomachinery and other critical engine components. Efficient performance of this effort is critical due to the significant impact of dynamic evaluation results on ground test and launch schedules, and requires direct familiarity with SSME and derivative systems, test data acquisition, and diagnostic software. Detailed analysis and evaluation of dynamic measurements obtained during SSME and advanced system ground test and flight operations was performed including analytical/statistical assessment of component dynamic behavior, and the development and implementation of analytical/statistical models to efficiently define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational condition. In addition, the SSME and J-2 data will be applied to develop vibroacoustic environments for advanced propulsion system components, as required. This study will provide timely assessment of engine component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. This contract will be performed through accomplishment of negotiated task orders.

An experimental investigation of multi-element airfoil ice accretion and resulting performance degradation

NASA Technical Reports Server (NTRS)

Potapczuk, Mark G.; Berkowitz, Brian M.

1989-01-01

An investigation of the ice accretion pattern and performance characteristics of a multi-element airfoil was undertaken in the NASA Lewis 6- by 9-Foot Icing Research Tunnel. Several configurations of main airfoil, slat, and flaps were employed to examine the effects of ice accretion and provide further experimental information for code validation purposes. The text matrix consisted of glaze, rime, and mixed icing conditions. Airflow and icing cloud conditions were set to correspond to those typical of the operating environment anticipated tor a commercial transport vehicle. Results obtained included ice profile tracings, photographs of the ice accretions, and force balance measurements obtained both during the accretion process and in a post-accretion evaluation over a range of angles of attack. The tracings and photographs indicated significant accretions on the slat leading edge, in gaps between slat or flaps and the main wing, on the flap leading-edge surfaces, and on flap lower surfaces. Force measurments indicate the possibility of severe performance degradation, especially near C sub Lmax, for both light and heavy ice accretion and performance analysis codes presently in use. The LEWICE code was used to evaluate the ice accretion shape developed during one of the rime ice tests. The actual ice shape was then evaluated, using a Navier-Strokes code, for changes in performance characteristics. These predicted results were compared to the measured results and indicate very good agreement.

Public versus Private Schools in Qatar: Is There a Literacy Gap?

ERIC Educational Resources Information Center

Cheema, Jehanzeb R.

2016-01-01

Recent studies have suggested that performance-related differences between private and public schools disappear once student background characteristics are accounted for. However, given the sometimes significant variation in economic, social and cultural norms across countries these findings may not have universal relevance. The main purpose of…

Laser surface texturing of polypropylene to increase adhesive bonding

NASA Astrophysics Data System (ADS)

Mandolfino, Chiara; Pizzorni, Marco; Lertora, Enrico; Gambaro, Carla

2018-05-01

In this paper, the main parameters of laser surface texturing of polymeric substrates have been studied. The final aim of the texturing is to increase the performance of bonded joints of grey-pigmented polypropylene substrates. The experimental investigation was carried out starting from the identification of the most effective treatment parameters, in order to achieve a good texture without compromising the characteristics of the bulk material. For each of these parameters, three values were individuated and 27 sets of samples were realised. The surface treatment was analysed and related to the mechanical characteristics of the bonded joints performing lap-shear tests. A statistical analysis in order to find the most influential parameter completed the work.

Somatotype in high performance female netball players may influence player position and the incidence of lower limb and back injuries

PubMed Central

Hopper, Diana M

1997-01-01

Aims To investigate the relation between somatotype, performance characteristics, and the incidence of injury during the Australian Netball Championships. Method Two hundred and forty high performance netball players competed at the Australian Netball Championships in which 213 (89%) were measured using the Heath-Carter somatotype scale. During these championships, in conjunction with the injury assessments, data analysis included a three factor analysis of variance (level of competition, playing position, and injury) for the dependent somatoype variables (endomorphy, mesomorphy, and ectopmorphy), and the level of significance was set at 0.05. Results For the three dependent somatotype variables, there were no main effects between endomorphy, mesomorphy, and ectopmorphy and the incidence of injury. However, for the mesomorphy and ectomorphy variables, significant main effects for the playing position were found. No main effects existed between the somatotype variables and levels of competition. Conclusion The somatotype variables did not influence the incidence of injury, but mesomorphy and ectopmorphy did influence the different playing positions. PMID:9298552

A Quality Assurance Initiative for Commercial-Scale Production in High-Throughput Cryopreservation of Blue Catfish Sperm

PubMed Central

Hu, E; Liao, T. W.; Tiersch, T. R.

2013-01-01

Cryopreservation of fish sperm has been studied for decades at a laboratory (research) scale. However, high-throughput cryopreservation of fish sperm has recently been developed to enable industrial-scale production. This study treated blue catfish (Ictalurus furcatus) sperm high-throughput cryopreservation as a manufacturing production line and initiated quality assurance plan development. The main objectives were to identify: 1) the main production quality characteristics; 2) the process features for quality assurance; 3) the internal quality characteristics and their specification designs; 4) the quality control and process capability evaluation methods, and 5) the directions for further improvements and applications. The essential product quality characteristics were identified as fertility-related characteristics. Specification design which established the tolerance levels according to demand and process constraints was performed based on these quality characteristics. Meanwhile, to ensure integrity throughout the process, internal quality characteristics (characteristics at each quality control point within process) that could affect fertility-related quality characteristics were defined with specifications. Due to the process feature of 100% inspection (quality inspection of every fish), a specific calculation method, use of cumulative sum (CUSUM) control charts, was applied to monitor each quality characteristic. An index of overall process evaluation, process capacity, was analyzed based on in-control process and the designed specifications, which further integrates the quality assurance plan. With the established quality assurance plan, the process could operate stably and quality of products would be reliable. PMID:23872356

Correlation and evaluation of inplane stability characteristics for an advanced bearingless main rotor

NASA Technical Reports Server (NTRS)

Weller, W. H.

1983-01-01

A program of experimental and analytical research was performed to demonstrate the degree of correlation achieved between measured and computed rotor inplane stability characteristics. The experimental data were obtained from hover and wind tunnel tests of a scaled bearingless main rotor model. Both isolated rotor and free-hub conditions were tested. Test parameters included blade built-in cone and sweep angles; rotor inplane structural stiffness and damping; pitch link stiffness and location; and fuselage damping, inertia, and natural frequency. Analytical results for many test conditions were obtained. In addition, the analytical and experimental results were examined to ascertain the effects of the test parameters on rotor ground and air resonance stability. The results from this program are presented herein in tabular and graphical form.

Dynamics and causalities of atmospheric and oceanic data identified by complex networks and Granger causality analysis

NASA Astrophysics Data System (ADS)

Charakopoulos, A. K.; Katsouli, G. A.; Karakasidis, T. E.

2018-04-01

Understanding the underlying processes and extracting detailed characteristics of spatiotemporal dynamics of ocean and atmosphere as well as their interaction is of significant interest and has not been well thoroughly established. The purpose of this study was to examine the performance of two main additional methodologies for the identification of spatiotemporal underlying dynamic characteristics and patterns among atmospheric and oceanic variables from Seawatch buoys from Aegean and Ionian Sea, provided by the Hellenic Center for Marine Research (HCMR). The first approach involves the estimation of cross correlation analysis in an attempt to investigate time-lagged relationships, and further in order to identify the direction of interactions between the variables we performed the Granger causality method. According to the second approach the time series are converted into complex networks and then the main topological network properties such as degree distribution, average path length, diameter, modularity and clustering coefficient are evaluated. Our results show that the proposed analysis of complex network analysis of time series can lead to the extraction of hidden spatiotemporal characteristics. Also our findings indicate high level of positive and negative correlations and causalities among variables, both from the same buoy and also between buoys from different stations, which cannot be determined from the use of simple statistical measures.

Evaluation of space shuttle main engine fluid dynamic frequency response characteristics

NASA Technical Reports Server (NTRS)

Gardner, T. G.

1980-01-01

In order to determine the POGO stability characteristics of the space shuttle main engine liquid oxygen (LOX) system, the fluid dynamic frequency response functions between elements in the SSME LOX system was evaluated, both analytically and experimentally. For the experimental data evaluation, a software package was written for the Hewlett-Packard 5451C Fourier analyzer. The POGO analysis software is documented and consists of five separate segments. Each segment is stored on the 5451C disc as an individual program and performs its own unique function. Two separate data reduction methods, a signal calibration, coherence or pulser signal based frequency response function blanking, and automatic plotting features are included in the program. The 5451C allows variable parameter transfer from program to program. This feature is used to advantage and requires only minimal user interface during the data reduction process. Experimental results are included and compared with the analytical predictions in order to adjust the general model and arrive at a realistic simulation of the POGO characteristics.

Metal coordination polymer derived mesoporous Co3O4 nanorods with uniform TiO2 coating as advanced anodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Geng, Hongbo; Ang, Huixiang; Ding, Xianguang; Tan, Huiteng; Guo, Guile; Qu, Genlong; Yang, Yonggang; Zheng, Junwei; Yan, Qingyu; Gu, Hongwei

2016-01-01

In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g-1, good cycling stability (around 803 mA h g-1 at a current density of 200 mA g-1 after 100 cycles), and stable rate performance (around 520 mA h g-1 at a current density of 1000 mA g-1). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g-1, good cycling stability (around 803 mA h g-1 at a current density of 200 mA g-1 after 100 cycles), and stable rate performance (around 520 mA h g-1 at a current density of 1000 mA g-1). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08570e

Pencil beam characteristics of the next-generation proton scanning gantry of PSI: design issues and initial commissioning results

NASA Astrophysics Data System (ADS)

Pedroni, E.; Meer, D.; Bula, C.; Safai, S.; Zenklusen, S.

2011-07-01

In this paper we report on the main design features, on the realization process and on selected first results of the initial commissioning of the new Gantry 2 of PSI for the delivery of proton therapy with new advanced pencil beam scanning techniques. We present briefly the characteristics of the new gantry system with main emphasis on the beam optics, on the characterization of the pencil beam used for scanning and on the performance of the scanning system. The idea is to give an overview of the major components of the whole system. The main long-term technical goal of the new equipment of Gantry 2 is to expand the use of pencil beam scanning to the whole spectrum of clinical indications including moving targets. We report here on the initial experience and problems encountered in the development of the system with selected preliminary results of the ongoing commissioning of Gantry 2.

Development of a new linearly variable edge filter (LVEF)-based compact slit-less mini-spectrometer

NASA Astrophysics Data System (ADS)

Mahmoud, Khaled; Park, Seongchong; Lee, Dong-Hoon

2018-02-01

This paper presents the development of a compact charge-coupled detector (CCD) spectrometer. We describe the design, concept and characterization of VNIR linear variable edge filter (LVEF)- based mini-spectrometer. The new instrument has been realized for operation in the 300 nm to 850 nm wavelength range. The instrument consists of a linear variable edge filter in front of CCD array. Low-size, light-weight and low-cost could be achieved using the linearly variable filters with no need to use any moving parts for wavelength selection as in the case of commercial spectrometers available in the market. This overview discusses the main components characteristics, the main concept with the main advantages and limitations reported. Experimental characteristics of the LVEFs are described. The mathematical approach to get the position-dependent slit function of the presented prototype spectrometer and its numerical de-convolution solution for a spectrum reconstruction is described. The performance of our prototype instrument is demonstrated by measuring the spectrum of a reference light source.

Advanced orbit transfer vehicle propulsion system study

NASA Technical Reports Server (NTRS)

Cathcart, J. A.; Cooper, T. W.; Corringrato, R. M.; Cronau, S. T.; Forgie, S. C.; Harder, M. J.; Mcallister, J. G.; Rudman, T. J.; Stoneback, V. W.

1985-01-01

A reuseable orbit transfer vehicle concept was defined and subsequent recommendations for the design criteria of an advanced LO2/LH2 engine were presented. The major characteristics of the vehicle preliminary design include a low lift to drag aerocapture capability, main propulsion system failure criteria of fail operational/fail safe, and either two main engines with an attitude control system for backup or three main engines to meet the failure criteria. A maintenance and servicing approach was also established for the advanced vehicle and engine concepts. Design tradeoff study conclusions were based on the consideration of reliability, performance, life cycle costs, and mission flexibility.

The DAG project, a 4m class telescope: the telescope main structure performances

NASA Astrophysics Data System (ADS)

Marchiori, G.; Busatta, A.; Ghedin, L.; Marcuzzi, E.; Manfrin, C.; Battistel, C.; Pirnay, O.; Flebus, Carlo; Yeşilyaprak, C.; Keskin, O.; Yerli, S.

2016-07-01

Dogu Anatolu Gözlemevi (DAG-Eastern Anatolia Observatory) Project is a 4m class optical, near-infrared Telescope and suitable enclosure which will be located at an altitude of 3.170m in Erzurum, Turkey. The DAG telescope is a project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope - ATASAM. The Project is being developed by the Belgian company AMOS (project leader), which is also the optics supplier and EIE GROUP, the Telescope Main Structure supplier and responsible for the final site integration. The design of the Telescope Main Structure fits in the EIE TBO Program which aims at developing a Dome/Telescope systemic optimization process for both performances and competitive costs based on previous project commitments like NTT, VLT, VST and ASTRI. The optical Configuration of the DAG Telescope is a Ritchey-Chretien with two Nasmyth foci and a 4m primary thin mirror controlled in shape and position by an Active Optic System. The main characteristics of the Telescope Main Structure are an Altitude-Azimuth light and rigid structure system with Direct Drive Systems for both axis, AZ Hydrostatic Bearing System and Altitude standard bearing system; both axes are equipped with Tape Encoder System. An innovative Control System characterizes the telescope performance.

Computer Drawing Method for Operating Characteristic Curve of PV Power Plant Array Unit

NASA Astrophysics Data System (ADS)

Tan, Jianbin

2018-02-01

According to the engineering design of large-scale grid-connected photovoltaic power stations and the research and development of many simulation and analysis systems, it is necessary to draw a good computer graphics of the operating characteristic curves of photovoltaic array elements and to propose a good segmentation non-linear interpolation algorithm. In the calculation method, Component performance parameters as the main design basis, the computer can get 5 PV module performances. At the same time, combined with the PV array series and parallel connection, the computer drawing of the performance curve of the PV array unit can be realized. At the same time, the specific data onto the module of PV development software can be calculated, and the good operation of PV array unit can be improved on practical application.

A photoelectric skylight polarimeter.

PubMed

Hariharan, T A; Sekera, Z

1966-09-01

A photoelectric skylight polarimeter to measure directly the Stokes parameters for plane polarized light is described. The basic principle of the instrument consists in the simultaneous measurement of the intensity of light (in the chosen spectral region) transmitted by polarizers oriented in four specific directions. The main features and performance characteristics of the instrument are briefly discussed.

Acorn Size as a Factor in Early Seedling Growth of Blue Oaks

Treesearch

Jerry Tecklin; Douglas D. McCreary

1991-01-01

Field performance was evaluated for blue oak (Quercus douglasii Hook. & Am.) acorns of different size classes (weights) and from different trees which produced predominantly small, medium, or large acorns. Emergence, height, and survival were monitored for two growing seasons. A parallel evaluation, mainly of root characteristics, was conducted...

[BALANCED SCORECARD AS A MANAGEMENT TOOL IN CLINICAL NUTRITION].

PubMed

Gutiérrez López, Cristina; Mauriz, Jose L; Culebras, Jesús M

2015-07-01

Nowadays, balanced scorecards have updated traditional management systems in the business sector. In this way, Kaplan and Norton propose performance measurement through several perspectives with a logical sequence: internal processes and learning impact client services, so that financial performance is affected. The aim of the present paper is to analyze the main characteristics of balanced scorecard when it is applied to non-for-profit companies and, specifically to the health sector in the clinical nutrition field. This model improves the economic vision of management with clinical indicators that represent healthcare professional's perspective. The balanced scorecard would allow a proper monitoring and tracking system for the main healthcare indicators. This contributes to a better control in comparison with standards that are associated with adequate quality assistance. Owing to the role of management accounting and cost calculations, the definition of healthcare professionals as clients or users, and clinical results relevance, it is necessary to adapt the balanced scorecard to the specific characteristics of the clinical field, redefining both perspectives and indicators. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Experimental study of the novel tuned mass damper with inerter which enables changes of inertance

NASA Astrophysics Data System (ADS)

Brzeski, P.; Lazarek, M.; Perlikowski, P.

2017-09-01

In this paper we present the experimental verification of the novel tuned mass damper which enables changes of inertance. Characteristic feature of the proposed device is the presence of special type of inerter. This inerter incorporates a continuously variable transmission that enables stepless changes of inertance. Thus, it enables to adjust the parameters of the damping device to the current forcing characteristic. In the paper we present and describe the experimental rig that consists of the massive main oscillator forced kinematically and the prototype of the investigated damper. We perform a series of dedicated experiments to characterize the device and asses its damping efficiency. Moreover, we perform numerical simulations using the simple mathematical model of investigated system. Comparing the numerical results and the experimental data we legitimize the model and demonstrate the capabilities of the investigated tuned mass damper. Presented results prove that the concept of the novel type of tuned mass damper can be realized and enable to confirm its main advantages. Investigated prototype device offers excellent damping efficiency in a wide range of forcing frequencies.

Study on the characteristics of a two gap capillary discharge

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

Huang, D.; Yang, L. J., E-mail: yanglj@mail.xjtu.edu.cn; Huo, P.

2015-02-15

The paper presents a new two-gap capillary (TGC) discharge structure. The prominent innovation is the introduction of the middle electrode, which divides the capillary into the trigger gap and the main gap. The discharge circuit of the TGC comprises the trigger circuit and the main circuit. The two circuits are used for the pre-ionization of the trigger gap and providing energy of 450 J for the main gap arc discharging, respectively. When the discharge initiates, the trigger gap is pre-ionized under high voltage pulse produced by trigger circuit, and meanwhile, the weakly ionized plasma is generated. The main circuit then maintainsmore » the expansion of the plasma, which is called soft capillary discharge. Afterwards, the main gap is shorted and discharges under a relatively low voltage. With the optimization of the circuit parameter, both the energy deposition ratio in main gap and the degree of plasma ionization are enhanced. The efficiency of the energy deposition is almost twice higher compared with that of the conventional capillary structure. The life performance test indicates that the erosion of the middle electrode and the trigger gap carbonization are the key factors that limit the life performance of the TGC.« less

Simulation and Experimental Investigation of Structural Dynamic Frequency Characteristics Control

PubMed Central

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results. PMID:22666072

Simulation and experimental investigation of structural dynamic frequency characteristics control.

PubMed

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results.

Students' approaches to medical school choice: relationship with students' characteristics and motivation.

PubMed

Wouters, Anouk; Croiset, Gerda; Schripsema, Nienke R; Cohen-Schotanus, Janke; Spaai, Gerard W G; Hulsman, Robert L; Kusurkar, Rashmi A

2017-06-12

The aim was to examine main reasons for students' medical school choice and their relationship with students' characteristics and motivation during the students' medical study. In this multisite cross-sectional study, all Year-1 and Year-4 students who had participated in a selection procedure in one of the three Dutch medical schools included in the study were invited to complete an online survey comprising personal data, their main reason for medical school choice and standard, validated questionnaires to measure their strength of motivation (Strength of Motivation for Medical School-Revised) and autonomous and controlled type of motivation (Academic Self-regulation Questionnaire). Four hundred seventy-eight students participated. We performed frequency analyses on the reasons for medical school choice and regression analyses and ANCOVAs to study their associations with students' characteristics and motivation during their medical study. Students indicated 'city' (Year-1: 24.7%, n=75 and Year-4: 36.0%, n=52) and 'selection procedure' (Year-1: 56.9%, n=173 and Year-4: 46.9%, n=68) as the main reasons for their medical school choice. The main reasons were associated with gender, age, being a first-generation university student, ethnic background and medical school, and no significant associations were found between the main reasons and the strength and type of motivation during the students' medical study. Most students had based their medical school choice on the selection procedure. If medical schools desire to achieve a good student-curriculum fit and attract a diverse student population aligning the selection procedure with the curriculum and taking into account various students' different approaches is important.

Thermoluminescence (TL) characteristics of perovskite-like KMgF 3 activated by La ions

NASA Astrophysics Data System (ADS)

Sepulveda, F.; Azorin, J.; Rivera, T.; Furetta, C.; Sanipoli, C.

2004-01-01

This paper reports the experimental results concerning the thermoluminescent characteristics of a new preparation of the fluoroperovskite KMgF 3:La + PTFE.The main thermoluminescent properties investigated were: the thermoluminescence (TL) response as a function of the absorbed dose, the precision obtainable in the dose measurement, the reproducibility of the TL readings and the threshold dose. The results obtained were then compared to the requirements of the ANSI protocol for thermoluminescent environmental dosimetry, resulting in a very good agreement with the required performances.

Repeatability analysis on LPFGs written by a CO2 laser

NASA Astrophysics Data System (ADS)

Nespereira, Marta; Castro Alves, D.; Coelho, João. M. P.; Monteiro, Fernando; Abreu, Manuel; Rebordão, J. M.

2014-08-01

The physical mechanisms involved in the writing process of long period fiber gratings (LPFG) using mid-infrared radiation emitted by CO2 lasers limit the obtained characteristics, in particular the minimum period that can be achieved. In order to evaluate the performances of a new methodology developed by us, we analyzed its capability to produce gratings with different periods (from 600 μm down to 300 μm). We also present a repeatability study on the obtained LPFG characteristics (mainly the resonant wavelength and grating length) for several values of the repetition period.

Microwave system performance for a solar power satellite during startup/shutdown operations

NASA Technical Reports Server (NTRS)

Arndt, G. D.; Berlin, L. A.

1979-01-01

The paper investigates the system performance and antenna characteristics under startup/shutdown conditions for the high power beam from a solar power satellite. Attention is given to the present microwave system reference configuration together with the dc power distribution system in the solar array and in the antenna. The pattern characteristics for the main beam, sidelobes, and grating lobes are examined for eight types of energizing configurations which include: random sequences, two types of concentric circles, and three types of line strips. In conclusion, it is noted that a proper choice of sequences should not cause environmental problems due to increased microwave radiation levels during the short time periods of energizing and de-energizing the antenna.

Selection method of terrain matching area for TERCOM algorithm

NASA Astrophysics Data System (ADS)

Zhang, Qieqie; Zhao, Long

2017-10-01

The performance of terrain aided navigation is closely related to the selection of terrain matching area. The different matching algorithms have different adaptability to terrain. This paper mainly studies the adaptability to terrain of TERCOM algorithm, analyze the relation between terrain feature and terrain characteristic parameters by qualitative and quantitative methods, and then research the relation between matching probability and terrain characteristic parameters by the Monte Carlo method. After that, we propose a selection method of terrain matching area for TERCOM algorithm, and verify the method correctness with real terrain data by simulation experiment. Experimental results show that the matching area obtained by the method in this paper has the good navigation performance and the matching probability of TERCOM algorithm is great than 90%

Chemical Functionalization of Graphene Family Members

NASA Astrophysics Data System (ADS)

Vacchi, Isabella Anna; Ménard-Moyon, Cécilia; Bianco, Alberto

2017-01-01

Thanks to their outstanding physicochemical properties, graphene and its derivatives are interesting nanomaterials with a high potential in several fields. Graphene, graphene oxide, and reduced graphene oxide, however, differ partially in their characteristics due to their diverse surface composition. Those differences influence the chemical reactivity of these materials. In the following chapter the reactivity and main functionalization reactions performed on graphene, graphene oxide, and reduced graphene oxide are discussed. A part is also dedicated to the main analytical techniques used for characterization of these materials. Functionalization of graphene and its derivatives is highly important to modulate their characteristics and design graphene-based conjugates with novel properties. Functionalization can be covalent by forming strong and stable bonds with the graphene surface, or non-covalent via π-π, electrostatic, hydrophobic, and/or van der Waals interactions. Both types of functionalization are currently exploited.

Advances in traction drive technology

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Anderson, N. E.; Rohn, D. A.

1983-01-01

Traction drives are traced from early uses as main transmissions in automobiles at the turn of the century to modern, high-powered traction drives capable of transmitting hundreds of horsepower. Recent advances in technology are described which enable today's traction drive to be a serious candidate for off-highway vehicles and helicopter applications. Improvements in materials, traction fluids, design techniques, power loss and life prediction methods will be highlighted. Performance characteristics of the Nasvytis fixed-ratio drive are given. Promising future drive applications, such as helicopter main transmissions and servo-control positioning mechanisms are also addressed.

The CP-PACS Project and Lattice QCD Results

NASA Astrophysics Data System (ADS)

Iwasaki, Y.

The aim of the CP-PACS project was to develop a massively parallel computer for performing numerical research in computational physics with primary emphasis on lattice QCD. The CP-PACS computer with a peak speed of 614 GFLOPS with 2048 processors was completed in September 1996, and has been in full operation since October 1996. We present an overview of the CP-PACS project and describe characteristics of the CP-PACS computer. The CP-PACS has been mainly used for hadron spectroscopy studies in lattice QCD. Main results in lattice QCD simulations are given.

Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

NASA Astrophysics Data System (ADS)

Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

2013-07-01

The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

Historical Delineation of Landscape Units Using Physical Geographic Characteristics and Land Use/Cover Change

NASA Astrophysics Data System (ADS)

Campos-Campos, Oswaldo; Cruz-Cárdenas, Gustavo; Aquino, Roque Juan Carrasco; Moncayo-Estrada, Rodrigo; Machuca, Martha Alicia Velázquez; Meléndez, Luis Arturo Ávila

2018-03-01

Landscape units are conceived as a part of the territory that share similar physical and geographic characteristics. Their delineation can contribute to identify the physical and social dynamics that emerge in the spatial environment and to propose strategies of planning and management of the territory. The main objective was to make a historical delineation of landscape units in the Duero river basin that demonstrate the dynamics of changes in the territory, the description of the actors involved, and the affectations in the natural and social environment. We analyzed the vegetation change and urban growth from 1983 to 2014, incorporating climatic, edaphic, and topographic variables. A Principal Component Analysis was performed with the information and results were used in Maximum Likelihood procedure to define different clusters based on environmental characteristics. We defined five categories from the Landsat images. Results showed landscape units with homogeneous environmental characteristics and some differences in the units' delineation were mainly influenced by political and socioeconomic factors. Temporally there was an increased tendency of landscape units, three in 1983, nine in 1990, 1995, 2000 and 2011, and eight in 2014. This increase resulted from territory fragmentation because of berries and avocado cultivars expansion over wooded area.

Space shuttle plume/simulation application: Results and math model supersonic data

NASA Technical Reports Server (NTRS)

Boyle, W.; Conine, B.; Bell, G.

1979-01-01

The analysis of pressure and gage wind tunnel data from space shuttle wind tunnel test IA138 was performed to define the aerodynamic influence of the main propulsion system and solid rocket booster plumes on the total vehicles, elements, and components of the space shuttle vehicle during the supersonic portion of ascent flight. A math model of the plume induced aerodynamic characteristics was developed for a range of Mach numbers to match the forebody aerodynamic math model. The base aerodynamic characteristics are presented in terms of forces and moments versus attitude. Total vehicle base and forebody aerodynamic characteristics are presented in terms of aerodynamic coefficients for Mach numbers from 1.55 to 2.5.

[Distribution characteristics of basic syndromes of chronic functional constipation and its related factors analysis].

PubMed

Zhao, Lei; Liao, Xiu-jun; Yang, Guan-gen; Mao, Wei-ming; Zhang, Xiu-feng; Deng, Qun; Wu, Wen-jing

2014-10-01

To explore the distribution characteristics of basic syndromes and its related factors in patients with chronic functional constipation (CFC). The complete data of 538 patients with CFC were collected and initial database was established with Epidata 3. 0. TCM syndrome typing was performed. The distribution characteristics of basic syndromes were analyzed using SPSS 17. 0 Software. The univariate and multivariate Logistic regression analyses were performed with SPSS 17. 0 Software to determine basic syndrome related factors such as age, engaged professionals, sleep quality, depression, mental stress, interpersonal relations, work fatigue, stimulating beverage, exercise conditions, Western medicine type of constipation, and so on. The TCM syndrome frequency of CFC patients was sequenced from high to low as qi deficiency syndrome (380 cases, 70.6%), qi stagnation syndrome (337 cases, 62.6%), blood deficiency syndrome (234 cases, 43.5%), yin deficiency syndrome (220 cases, 40.9%), yang deficiency syndrome (197 cases, 36.6%), and others(58 cases, 10. 8%) . Most patients were complicated with complex syndromes, and the most common complex syndromes were qi deficiency complicated qi stagnation syndrome (275 cases, 51.1%) and qi deficiency complicated blood deficiency syndrome (222 cases, 41.3%). Aging, work fatigue, and exercise conditions were main related factors for qi deficiency syndrome (P <0. 01, P <0. 05). Poor emotional (depression and anxiety tendencies), mental stress, interpersonal relations, defecation barriers constipation were main related factors for qi stagnation syndrome (P <0.01). Sleep quality and poor emotional (depression and anxiety tendencies) were main related factors for blood deficiency syndrome (P <0. 01, P < 0.05). Stimulating beverages were main related factor for yin deficiency syndrome (P <0.05). Engaged in mental work and slow transit constipation were main related factors for yang deficiency syndrome (P < 0. 01, P <0. 05). CFC is featured as complex syndromes. The most common complex syndromes were qi deficiency complicated qi stagnation syndrome and qi deficiency complicated blood deficiency syndrome. Basic syndrome related factors such as age, engaged professionals, sleep quality, poor emotional (depression and anxiety tendencies), mental stress, interpersonal relations, work fatigue, stimulating beverage, exercise conditions, Western medicine type of constipation were associated with the distribution of CFC syndromes.

Influence of the association of the EVA and NBR on the characteristics of modified bitumen

NASA Astrophysics Data System (ADS)

Bensaada, A.; Soudani, K.; Haddadi, S.; Saoula, S.

2015-03-01

Durability and the performance of pavement depend mainly on the characteristics of materials which change over time like all other organic substances. They are subject to significant changes due to environmental conditions during the different phases of use. In the present work we investigated experimentally the influence of the association of ethyl vinyl acetate polymer (EVA) with an industrial waste, acrylonitrile-butadiene rubber (NBR) on the modification of bitumen AC 35-50 and its rheological behavior. The incorporation of NBR and EVA in the bitumen improved its intrinsic characteristics (softening point, penetration and ductility). In addition to improving the characteristics of bituminous binders that will affect the durability of bituminous structures, the environment will be preserved by the recycling of industrial waste.

Evaluation of CFD to Determine Two-Dimensional Airfoil Characteristics for Rotorcraft Applications

NASA Technical Reports Server (NTRS)

Smith, Marilyn J.; Wong, Tin-Chee; Potsdam, Mark; Baeder, James; Phanse, Sujeet

2004-01-01

The efficient prediction of helicopter rotor performance, vibratory loads, and aeroelastic properties still relies heavily on the use of comprehensive analysis codes by the rotorcraft industry. These comprehensive codes utilize look-up tables to provide two-dimensional aerodynamic characteristics. Typically these tables are comprised of a combination of wind tunnel data, empirical data and numerical analyses. The potential to rely more heavily on numerical computations based on Computational Fluid Dynamics (CFD) simulations has become more of a reality with the advent of faster computers and more sophisticated physical models. The ability of five different CFD codes applied independently to predict the lift, drag and pitching moments of rotor airfoils is examined for the SC1095 airfoil, which is utilized in the UH-60A main rotor. Extensive comparisons with the results of ten wind tunnel tests are performed. These CFD computations are found to be as good as experimental data in predicting many of the aerodynamic performance characteristics. Four turbulence models were examined (Baldwin-Lomax, Spalart-Allmaras, Menter SST, and k-omega).

The influence of visual characteristics of barriers on railway noise perception.

PubMed

Maffei, Luigi; Masullo, Massimiliano; Aletta, Francesco; Di Gabriele, Maria

2013-02-15

Noise annoyance is considered as the main effect of noise, it is a complex and multifaceted psychological concept dealing with immediate behavioral and evaluative aspects. In the last decades the research has intensely investigated the correlation between noise exposure and noise annoyance, nevertheless recent studies confirm that non-auditory factors influence the noise perception of individuals. In particular audio-video interaction can play a fundamental role. Today Immersive Virtual Reality (IVR) systems allow building laboratory test providing realistic experiences of the surrounding environment to detect more accurate information about the reactions of the local population. Regarding the interventions for environmental noise control the barriers represent the main solution; however some aspects related to their visual characteristic have to be further investigated. This paper presented a case study, where a sample of residents living close to a railway line assessed noise-related aspects for several barriers with different visual characteristics in an IVR laboratory test. In particular, three main factors were analyzed: the barrier type concerning the visibility of the noise source through the screen, the visual aspect of the barrier concerning some aesthetic issues and the noise level at the receiver concerning the acoustic performance of the barrier and the magnitude of the sound source. The main results of the ANOVA analysis showed that for transparent barriers Perceived Loudness and Noise Annoyance were judged lower than for opaque barriers; this difference increased as noise level increased. Copyright © 2012. Published by Elsevier B.V.

Numerical and experimental investigation of the effect of geometry on combustion characteristics of solid-fuel ramjet

NASA Astrophysics Data System (ADS)

Gong, Lunkun; Chen, Xiong; Musa, Omer; Yang, Haitao; Zhou, Changsheng

2017-12-01

Numerical and experimental investigation on the solid-fuel ramjet was carried out to study the effect of geometry on combustion characteristics. The two-dimensional axisymmetric program developed in the present study adopted finite rate chemistry and second-order moment turbulence-chemistry models, together with k-ω shear stress transport (SST) turbulence model. Experimental data were obtained by burning cylindrical polyethylene using a connected pipe facility. The simulation results show that a fuel-rich zone near the solid fuel surface and an air-rich zone in the core exist in the chamber, and the chemical reactions occur mainly in the interface of this two regions; The physical reasons for the effect of geometry on regression rate is the variation of turbulent viscosity due to the geometry change. Port-to-inlet diameter ratio is the main parameter influencing the turbulent viscosity, and a linear relationship between port-to-inlet diameter and regression rate were obtained. The air mass flow rate and air-fuel ratio are the main influencing factors on ramjet performances. Based on the simulation results, the correlations between geometry and air-fuel ratio were obtained, and the effect of geometry on ramjet performances was analyzed according to the correlation. Three-dimensional regression rate contour obtained experimentally indicates that the regression rate which shows axisymmetric distribution due to the symmetry structure increases sharply, followed by slow decrease in axial direction. The radiation heat transfer in recirculation zone cannot be ignored. Compared with the experimental results, the deviations of calculated average regression rate and characteristic velocity are about 5%. Concerning the effect of geometry on air-fuel ratio, the deviations between experimental and theoretical results are less than 10%.

Taxonomy Discrimination of the Tina Asteroid Family via Photometric Color Indices (Abstract)

NASA Astrophysics Data System (ADS)

Galiazzo, M. A.; Zeilinger, W. W.; Carraro, G.; Oszkiewicz, D.

2017-12-01

(Abstract only) This work aims to expand our understanding of the physical characteristics of the Tina asteroid family in the main belt. This small group is unusual, as the only asteroid group currently known to be completely contained in the stable island of one of the principal secular resonances of the main belt, the n6. This family is almost near the center of the main asteroid belt, having its members with a semi-major axis between 2.765 au and 2.807 au. Its largest body is (1222) Tina, 21 km in diameter and an X-type asteroid. We aim to find their taxonomic types by performing correlations with their color indices.

Detecting Different Types of Reading Difficulties: A Comparison of Tests

ERIC Educational Resources Information Center

Moore, Danielle M.; Porter, Melanie A.; Kohnen, Saskia; Castles, Anne

2012-01-01

The focus of this paper is on the assessment of the two main processes that children must acquire at the single word reading level: word recognition (lexical) and decoding (nonlexical) skills. Guided by the framework of the dual route model, this study aimed to (1) investigate the impact of item characteristics on test performance, and (2)…

Performance of a Turboprop Engine with Heat Recovery in Off-Design Conditions

NASA Astrophysics Data System (ADS)

Andriani, Roberto; Ghezzi, Umberto; Gamma, Fausto; Ingenito, Antonella; Agresta, Antonio

2013-09-01

The research for fuel consumption and pollution reduction in new generation aero engines has indicated intercooling and regeneration as very effective methods for this purpose. Hence, different countries have joined their efforts in common research programs, to develop new gas turbine engines able to reduce considerably the fuel consumption and the ambient impact by means of these two techniques. To study their effects on the engine performance and characteristics, a thermodynamic numerical program that simulates the behavior of a turboprop engine with intercooling and regeneration in different operating conditions has been developed. After the parametric study, and the definition of the design conditions, the off-design analysis is carried on, comparing the main characteristics of the intercooled-regenerated turboprop with those of a conventional engine. Then, once a particular mission profile was fixed, the engine performance, in particular the equivalent power, the fuel consumption and the heat exchanger weight were discussed.

Study of the GEM detector performance in BM@N experiment

NASA Astrophysics Data System (ADS)

Bazylev, Sergei; Kapishin, Mikhail; Kapusniak, Kacper; Karjavine, Vladimir; Khabarov, Sergei; Kolesnikov, Alexander; Kulish, Elena; Lenivenko, Vasilisa; Makankin, Alexander; Maksymchuk, Anna; Mehl, Bertrand; De Oliveira, Rui; Palchik, Vladimir; Pokatashkin, Gleb; Rodriguez, A.; Rufanov, Igor; Shutov, Alexander; Slepnev, Ilya; Slepnev, Vyacheslav; Vasiliev, Sergei; Zinchenko, Alexander

2018-04-01

BM@N is the fixed target experiment at the accelerator complex NICA-Nuclotron aimed to study nuclear matter in the relativistic heavy ion collisions. Triple-GEM detectors were identified as appropriate for the BM@N tracking system located inside the analyzing magnet. Seven GEM chambers are integrated into the BM@N experimental setup and data acquisition system. GEM construction, main characteristics and first obtained results of the GEM tracking system performance in the technical run with the deuteron beam are shortly reviewed.

Bilateral Impedance Control For Telemanipulators

NASA Technical Reports Server (NTRS)

Moore, Christopher L.

1993-01-01

Telemanipulator system includes master robot manipulated by human operator, and slave robot performing tasks at remote location. Two robots electronically coupled so slave robot moves in response to commands from master robot. Teleoperation greatly enhanced if forces acting on slave robot fed back to operator, giving operator feeling he or she manipulates remote environment directly. Main advantage of bilateral impedance control: enables arbitrary specification of desired performance characteristics for telemanipulator system. Relationship between force and position modulated at both ends of system to suit requirements of task.

Life prediction and reliability assessment of lithium secondary batteries

NASA Astrophysics Data System (ADS)

Eom, Seung-Wook; Kim, Min-Kyu; Kim, Ick-Jun; Moon, Seong-In; Sun, Yang-Kook; Kim, Hyun-Soo

Reliability assessment of lithium secondary batteries was mainly considered. Shape parameter (β) and scale parameter (η) were calculated from experimental data based on cycle life test. We also examined safety characteristics of lithium secondary batteries. As proposed by IEC 62133 (2002), we had performed all of the safety/abuse tests such as 'mechanical abuse tests', 'environmental abuse tests', 'electrical abuse tests'. This paper describes the cycle life of lithium secondary batteries, FMEA (failure modes and effects analysis) and the safety/abuse tests we had performed.

Performance of private sector health care: implications for universal health coverage.

PubMed

Morgan, Rosemary; Ensor, Tim; Waters, Hugh

2016-08-06

Although the private sector is an important health-care provider in many low-income and middle-income countries, its role in progress towards universal health coverage varies. Studies of the performance of the private sector have focused on three main dimensions: quality, equity of access, and efficiency. The characteristics of patients, the structures of both the public and private sectors, and the regulation of the sector influence the types of health services delivered, and outcomes. Combined with characteristics of private providers-including their size, objectives, and technical competence-the interaction of these factors affects how the sector performs in different contexts. Changing the performance of the private sector will require interventions that target the sector as a whole, rather than individual providers alone. In particular, the performance of the private sector seems to be intrinsically linked to the structure and performance of the public sector, which suggests that deriving population benefit from the private health-care sector requires a regulatory response focused on the health-care sector as a whole. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reflections on the career of Brazilian Paralympic athletes.

PubMed

Haiachi, Marcelo de Castro; Cardoso, Vinícius Denardin; Reppold, Alberto Reinaldo; Gaya, Adroaldo Cezar Araújo

2016-10-01

The proximity of the Paralympic Games Rio 2016 opens the discussion about the possibility of building a career in Paralympic sport. This study aims to present the characteristics and challenges present in the sporting career of the Brazilian Paralympic athlete. The study was structured under three main guiding topics: the different moments of Paralympic Sport, the career characteristics of paralympians and the consequences of sports results for their careers. Currently, Paralympic sports has its focus on high performance, as the constant necessity for good results is an ever present reality. The characteristics and challenges of sporting careers reveal the current situation for Brazilian Paralympic sports in all of its stages (pre-transition, transition and post-transition). Upon reflecting on the career of the Brazilian paralympic athlete a debate opens up concerning future perspectives and particularly on an understanding of the existing challenges for consolidation. Structural problems such as venues for training, lack of awareness on the part of the private sector and the non-renewal of human resources, seem to be the main obstacles for the consolidation of paralympic careers in Brazil.

Wind Extraction for Natural Ventilation

NASA Astrophysics Data System (ADS)

Fagundes, Tadeu; Yaghoobian, Neda; Kumar, Rajan; Ordonez, Juan

2017-11-01

Due to the depletion of energy resources and the environmental impact of pollution and unsustainable energy resources, energy consumption has become one of the main concerns in our rapidly growing world. Natural ventilation, a traditional method to remove anthropogenic and solar heat gains, proved to be a cost-effective, alternative method to mechanical ventilation. However, while natural ventilation is simple in theory, its detailed design can be a challenge, particularly for wind-driven ventilation, which its performance highly involves the buildings' form, surrounding topography, turbulent flow characteristics, and climate. One of the main challenges with wind-driven natural ventilation schemes is due to the turbulent and unpredictable nature of the wind around the building that impose complex pressure loads on the structure. In practice, these challenges have resulted in founding the natural ventilation mainly on buoyancy (rather than the wind), as the primary force. This study is the initial step for investigating the physical principals of wind extraction over building walls and investigating strategies to reduce the dependence of the wind extraction on the incoming flow characteristics and the target building form.

A model for sequential decoding overflow due to a noisy carrier reference. [communication performance prediction

NASA Technical Reports Server (NTRS)

Layland, J. W.

1974-01-01

An approximate analysis of the effect of a noisy carrier reference on the performance of sequential decoding is presented. The analysis uses previously developed techniques for evaluating noisy reference performance for medium-rate uncoded communications adapted to sequential decoding for data rates of 8 to 2048 bits/s. In estimating the ten to the minus fourth power deletion probability thresholds for Helios, the model agrees with experimental data to within the experimental tolerances. The computational problem involved in sequential decoding, carrier loop effects, the main characteristics of the medium-rate model, modeled decoding performance, and perspectives on future work are discussed.

Study on each phase characteristics of the whole coal life cycle and their ecological risk assessment-a case of coal in China.

PubMed

Dai, Wenting; Dong, Jihong; Yan, Wanglin; Xu, Jiren

2017-01-01

The paper divided the whole coal life cycle, explained each phase characteristics, and took coal mine in China as a study case to assess the ecological risk in coal utilization phase. The main conclusions are as follows: (1) the whole coal life cycle is divided into coal mining, processing, transportation, utilization, and waste disposal. (2) The key points of production organization and characteristics in the five phases have great differences. The coal mining phase is characterized by the damage of the key ecological factors (water, soil, atmosphere, vegetation, etc.) damaged while the coal processing phase by discharging waste. The characteristics in coal transportation phase mainly performance as escaping and migration of atmospheric pollutants. In coal utilization phase, the main characteristics are aggravation of greenhouse effect. The main characteristics of waste disposal phase are accumulation of negative ecological effects on the land. (3) The ecological risk of soil heavy metals is serious in coal utilization phase. The potential ecological hazard coefficients of Pb and As in coal, residue and ash are all lower than 40, presenting low environmental impact on soil; the potential ecological risk coefficients of Cd are higher than 60, nearly half of their potential ecological risk coefficients are higher than 160, which presents high environmental pollution impact on soil; Hg's potential ecological risk coefficients are higher than 320, presenting the highest environmental pollution impact on soil; the comprehensive pollution indexes in coal, residue, and ash are relatively high, which means the pollution hazard potential to soil environment is high. (4) The ecological risk of the atmospheric solid suspended matter is relatively strong in coal utilization phase. The ecological risk of Cd and As in primary flue gas is both lower than net flue gas. The geoaccumulation indexes of Cd and Hg in primary flue gas and net flue gas are both higher than 5, presenting the very strong ecological risk; 50 % of the geoaccumulation index values of As are between 3 and 4, which has also presenting a strong ecological risk while Pb does not present the ecological risk characterization.

On use of characteristic wavelengths of track irregularities to predict track portions with deteriorated wheel/rail forces

NASA Astrophysics Data System (ADS)

Xu, Lei; Zhai, Wanming; Chen, Zhaowei

2018-05-01

The dynamic performance of the railway vehicles and the guiding tracks is mainly governed by the wheel-rail interactions, particularly in cases of track irregularities. In this work, a united model was developed to investigate the track portions subject to violent wheel/rail forces triggered by track irregularities at middle-low frequencies. In the modeling procedures, a time-frequency unification method combining wavelet transform and Wigner-Ville distribution for characterizing time-frequency characteristics of track irregularities and a three-dimensional nonlinear model for describing vehicle-track interaction signatures were developed and coupled, based on which the method for predicting track portions subject to deteriorated wheel/rail forces was proposed. The theoretical models developed in this paper were comprehensively validated by numerical investigations. The significance of this present study mainly lies on offering a new path to establish correlation and realize mutual prediction between track irregularity and railway system dynamics.

Electromagnetic Emission from Electric Propulsions under Ground Conditions

NASA Astrophysics Data System (ADS)

Baranov, S. V.; Vazhenin, N. A.; Plokhikh, A. P.; Popov, G. A.

2017-12-01

Analysis and methodological generalization of available methods used for determining characteristics of intrinsic emission from electric propulsions (EP) in a radio-frequency range that can be the interference for the "Earth-spacecraft (SC)" channel of the space communication system are the subjects of this paper. Intrinsic emission from the electric propulsion in a radio-frequency range is examined in detail by the example of a measuring complex developed in RIAME MAI and the measurement results are presented. The electric field intensity distribution in a radio-frequency range for the vertical and horizontal polarizations of the received emission is considered as the main characteristics. Measurements performed for the EP intrinsic emission by using the developed complex and measurements performed in metal vacuum chambers are compared and comparative results are presented in the paper.

Improvement of technical purpose materials performance characteristics with the radio frequency low pressure plasma

NASA Astrophysics Data System (ADS)

Makhotkina, L. Yu; Khristoliubova, V. I.

2017-11-01

The main aim of the work is to solve the actual problem of increasing the competitiveness of tanning products by reducing the prime cost and improving the quality of finished products due to the increased durability of the working elements of tanneries. The impact of the low pressure radio frequency (RF) plasma in the processes of treating for modification of the materials for special purposes is considered in the article. The results of working elements of tanneries and the materials for special purposes sample processing by a RF low pressure plasma are described. As a result of leather materials nano structuring and nano modifying physical, mechanical and hygienic characteristics were increased. Processing of the technical purpose materials allows to increase operational performance of products and extend their lifespan.

Students’ approaches to medical school choice: relationship with students’ characteristics and motivation

PubMed Central

Croiset, Gerda; Schripsema, Nienke R.; Cohen-Schotanus, Janke; Spaai, Gerard W.G.; Hulsman, Robert L.; Kusurkar, Rashmi A.

2017-01-01

Objectives The aim was to examine main reasons for students’ medical school choice and their relationship with students’ characteristics and motivation during the students’ medical study. Methods In this multisite cross-sectional study, all Year-1 and Year-4 students who had participated in a selection procedure in one of the three Dutch medical schools included in the study were invited to complete an online survey comprising personal data, their main reason for medical school choice and standard, validated questionnaires to measure their strength of motivation (Strength of Motivation for Medical School-Revised) and autonomous and controlled type of motivation (Academic Self-regulation Questionnaire). Four hundred seventy-eight students participated. We performed frequency analyses on the reasons for medical school choice and regression analyses and ANCOVAs to study their associations with students’ characteristics and motivation during their medical study. Results Students indicated ‘city’ (Year-1: 24.7%, n=75 and Year-4: 36.0%, n=52) and ‘selection procedure’ (Year-1: 56.9%, n=173 and Year-4: 46.9%, n=68) as the main reasons for their medical school choice. The main reasons were associated with gender, age, being a first-generation university student, ethnic background and medical school, and no significant associations were found between the main reasons and the strength and type of motivation during the students’ medical study. Conclusions Most students had based their medical school choice on the selection procedure. If medical schools desire to achieve a good student-curriculum fit and attract a diverse student population aligning the selection procedure with the curriculum and taking into account various students’ different approaches is important. PMID:28624778

The Effectiveness of Using Teacher-Teacher Wikis in Collaborative Lesson Planning and Its Impact on Teacher's Classroom Performance

ERIC Educational Resources Information Center

Al-Shareef, Samar Yahya; Al-Qarni, Reem Ali

2016-01-01

The paper highlights the main aspects and characteristic features of teacher-teacher Wikis, which are considered to be the most effective teaching and learning tools. The research studies the effectiveness of using Wikis by teachers during collaborative lesson planning. It also traces the impact of teacher-teacher Wikis on the teachers'…

Gaseous Emissions Results from a Three-Cup Flametube Test of a Third-Generation Swirl-Venturi Lean Direct Injection Combustion Concept

NASA Technical Reports Server (NTRS)

Tacina, Kathleen M.; Podboy, Derek P.; Lee, Phil; Dam, Bidhan

2017-01-01

This paper summarizes the development of lean direct injection (LDI) combustor technology at, or in collaboration with, the NASA Glenn Research Center. These configurations differ mainly in fuel-air mixing strategy. The paper reviews the NOx performance and operability characteristics of multiple LDI configurations tested at NASA Glenn.

CHARACTERISTICS OF FARM WORKERS AS RELATED TO STABILIZATION OF THE WORK FORCE.

ERIC Educational Resources Information Center

METZLER, WILLIAM H.

PROBLEMS OF THE MIGRANTS INCLUDE THEIR LACK OF DESIRE TO LEARN NEW SKILLS AND TO ADJUST TO NEW SITUATIONS, THEIR NEED TO MIGRATE TO FIND EMPLOYMENT DURING CERTAIN OFF-SEASONS, THEIR LACK OF TRAINING FOR MANY KINDS OF JOBS, THEIR PREJUDICED ATTITUDE TOWARD JOBS MAINLY PERFORMED BY FOREIGN OR COLORED WORKERS, THEIR TENDENCY TO LEAVE A JOB WHEN…

Do Personality and Learning Climate Predict Competence for Learning? An Investigation in a Greek Academic Setting

ERIC Educational Resources Information Center

Ntalianis, Filotheos

2010-01-01

The effects of personal characteristics (e.g. personality, aptitude, gender) on student performance, such as Grade Point Average (GPA) and course grades, have been systematically researched, with the emphasis being mainly on outcomes rather than the processes leading to them. The purpose of this paper is to shift the focus to students' perceived…

Introducing hydrological information in rainfall intensity-duration thresholds

NASA Astrophysics Data System (ADS)

Greco, Roberto; Bogaard, Thom

2016-04-01

Regional landslide hazard assessment is mainly based on empirically derived precipitation-intensity-duration (PID) thresholds. Generally, two features of rainfall events are plotted to discriminate between observed occurrence and absence of occurrence of mass movements. Hereafter, a separation line is drawn in logarithmic space. Although successfully applied in many case studies, such PID thresholds suffer from many false positives as well as limited physical process insight. One of the main limitations is indeed that they do not include any information about the hydrological processes occurring along the slopes, so that the triggering is only related to rainfall characteristics. In order to introduce such an hydrological information in the definition of rainfall thresholds for shallow landslide triggering assessment, in this study the introduction of non-dimensional rainfall characteristics is proposed. In particular, rain storm depth, intensity and duration are divided by a characteristic infiltration depth, a characteristic infiltration rate and a characteristic duration, respectively. These latter variables depend on the hydraulic properties and on the moisture state of the soil cover at the beginning of the precipitation. The proposed variables are applied to the case of a slope covered with shallow pyroclastic deposits in Cervinara (southern Italy), for which experimental data of hourly rainfall and soil suction were available. Rainfall thresholds defined with the proposed non-dimensional variables perform significantly better than those defined with dimensional variables, either in the intensity-duration plane or in the depth-duration plane.

Optical design of CCAT

NASA Astrophysics Data System (ADS)

Cortés-Medellín, Germán; Herter, Terry

2006-06-01

The Cornell Caltech Atacama Telescope (CCAT) is a 25m-class sub-millimeter radio telescope capable of operating from 300GHz up to 1.5 THz. The CCAT optical design is an f/8 Ritchey-Chretien (RC) system in a dual Nasmyth focus configuration and a 20 arc-min FOV (diffraction limited imaging performance better than 0.31" at the edge of the field). The large FOV is capable to accommodate up to 1200x1200 (Nyquist Sampled) Pixels at 200 microns, with better than 96% Strehl ratio. The telescope pedestal assembly is a counterbalanced elevation over azimuth design. The main reflector surface is segmented and actively controlled to attain diffraction-limited operation up to 200 microns. A flat Mirror located behind the main reflector vertex provides the optical path relay to either of the two Nasmyth platforms and to a bent-Cassegrain focus for surface calibration. We present the imaging characteristics of the CCAT over the 20arc-min FOV at 200 microns at the Nasmyth focal plane, as well as the positioning sensitivity analysis of CCAT's 3.2m-diameter sub-reflector given in terms of the telescope optical performance, antenna pointing requirements and sub-reflector chopping characteristics.

Single-photon semiconductor photodiodes for distributed optical fiber sensors: state of the art and perspectives

NASA Astrophysics Data System (ADS)

Ripamonti, Giancarlo; Lacaita, Andrea L.

1993-03-01

The extreme sensitivity and time resolution of Geiger-mode avalanche photodiodes (GM- APDs) have already been exploited for optical time domain reflectometry (OTDR). Better than 1 cm spatial resolution in Rayleigh scattering detection was demonstrated. Distributed and quasi-distributed optical fiber sensors can take advantage of the capabilities of GM-APDs. Extensive studies have recently disclosed the main characteristics and limitations of silicon devices, both commercially available and developmental. In this paper we report an analysis of the performance of these detectors. The main characteristics of GM-APDs of interest for distributed optical fiber sensors are briefly reviewed. Command electronics (active quenching) is then introduced. The detector timing performance sets the maximum spatial resolution in experiments employing OTDR techniques. We highlight that the achievable time resolution depends on the physics of the avalanche spreading over the device area. On the basis of these results, trade-off between the important parameters (quantum efficiency, time resolution, background noise, and afterpulsing effects) is considered. Finally, we show first results on Germanium devices, capable of single photon sensitivity at 1.3 and 1.5 micrometers with sub- nanosecond time resolution.

Vibration characteristics of OH-58A helicopter main rotor transmission

NASA Technical Reports Server (NTRS)

Lewicki, David G.; Coy, John J.

1987-01-01

Experimental vibration tests covering a range of torque and speed conditions were performed on the OH-58A helicopter main rotor transmission at the NASA Lewis Research Center. Signals from accelerometers located on the transmission housing were analyzed by using Fourier spectra, power spectral density functions, and averaging techniques. Most peaks of the Fourier spectra occurred at the spiral bevel and planetary gear mesh harmonics. The highest level of vibration occurred at the spiral bevel meshing frequency. Transmission speed and vibration measurement location had a significant effect on measured vibration; transmission torque and measurement direction had a small effect.

Non-faradic carbon nanotube-based supercapacitors: state of the art. Analysis of all the main scientific contributions from 1997 to our days

NASA Astrophysics Data System (ADS)

Bondavalli, P.; Pribat, D.; Schnell, J.-P.; Delfaure, C.; Gorintin, L.; Legagneux, P.; Baraton, L.; Galindo, C.

2012-10-01

This contribution deals with the state of the art of studies concerning the fabrication of electric double-layer capacitors (EDLCs) also called super- or ultracapacitors and obtained using carbon nanotubes (CNTs) without exploiting Faradic reactions. From the first work published in 1997, EDLCs fabricated using carbon nanotubes as constitutive material for electrodes showed very interesting characteristics. It appeared that they could potentially outperform traditional technologies based on activated carbon. Different methods to fabricate the CNT-based electrodes have been proposed in order to improve the performances (mainly energy densities and power densities), for example filtration, direct growth on metal collector or deposition using an air-brush technique. In this contribution we will introduce the main works in the field. Finally, we will point out an emerging interest for supercapacitors fabricated on flexible substrates, exploiting the outstanding mechanical performances of CNTs, for new kinds of applications such as portable electronics.

Scalability Analysis of Gleipnir: A Memory Tracing and Profiling Tool, on Titan

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

Janjusic, Tommy; Kartsaklis, Christos; Wang, Dali

2013-01-01

Application performance is hindered by a variety of factors but most notably driven by the well know CPU-memory speed gap (also known as the memory wall). Understanding application s memory behavior is key if we are trying to optimize performance. Understanding application performance properties is facilitated with various performance profiling tools. The scope of profiling tools varies in complexity, ease of deployment, profiling performance, and the detail of profiled information. Specifically, using profiling tools for performance analysis is a common task when optimizing and understanding scientific applications on complex and large scale systems such as Cray s XK7. This papermore » describes the performance characteristics of using Gleipnir, a memory tracing tool, on the Titan Cray XK7 system when instrumenting large applications such as the Community Earth System Model. Gleipnir is a memory tracing tool built as a plug-in tool for the Valgrind instrumentation framework. The goal of Gleipnir is to provide fine-grained trace information. The generated traces are a stream of executed memory transactions mapped to internal structures per process, thread, function, and finally the data structure or variable. Our focus was to expose tool performance characteristics when using Gleipnir with a combination of an external tools such as a cache simulator, Gl CSim, to characterize the tool s overall performance. In this paper we describe our experience with deploying Gleipnir on the Titan Cray XK7 system, report on the tool s ease-of-use, and analyze run-time performance characteristics under various workloads. While all performance aspects are important we mainly focus on I/O characteristics analysis due to the emphasis on the tools output which are trace-files. Moreover, the tool is dependent on the run-time system to provide the necessary infrastructure to expose low level system detail; therefore, we also discuss any theoretical benefits that can be achieved if such modules were present.« less

Structural Analysis: Folds Classification of metasedimentary rock in the Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Shamsuddin, A.

2017-10-01

Understanding shear zone characteristics of deformation are a crucial part in the oil and gas industry as it might increase the knowledge of the fracture characteristics and lead to the prediction of the location of fracture zones or fracture swarms. This zone might give high influence on reservoir performance. There are four general types of shear zones which are brittle, ductile, semibrittle and brittle-ductile transition zones. The objective of this study is to study and observe the structural geometry of the shear zones and its implication as there is a lack of understanding, especially in the subsurface area because of the limitation of seismic resolution. A field study was conducted on the metasedimentary rocks (shear zone) which are exposed along the coastal part of the Peninsular Malaysia as this type of rock resembles the types of rock in the subsurface. The analysis in this area shows three main types of rock which are non-foliated metaquartzite and foliated rock which can be divided into slate and phyllite. Two different fold classification can be determined in this study. Layer 1 with phyllite as the main type of rock can be classified in class 1C and layer 2 with slate as the main type of rock can be classified in class 1A. This study will benefit in predicting the characteristics of the fracture and fracture zones.

Automatic performance budget: towards a risk reduction

NASA Astrophysics Data System (ADS)

Laporte, Philippe; Blake, Simon; Schmoll, Jürgen; Rulten, Cameron; Savoie, Denis

2014-08-01

In this paper, we discuss the performance matrix of the SST-GATE telescope developed to allow us to partition and allocate the important characteristics to the various subsystems as well as to describe the process in order to verify that the current design will deliver the required performance. Due to the integrated nature of the telescope, a large number of parameters have to be controlled and effective calculation tools must be developed such as an automatic performance budget. Its main advantages consist in alleviating the work of the system engineer when changes occur in the design, in avoiding errors during any re-allocation process and recalculate automatically the scientific performance of the instrument. We explain in this paper the method to convert the ensquared energy (EE) and the signal-to-noise ratio (SNR) required by the science cases into the "as designed" instrument. To ensure successful design, integration and verification of the next generation instruments, it is of the utmost importance to have methods to control and manage the instrument's critical performance characteristics at its very early design steps to limit technical and cost risks in the project development. Such a performance budget is a tool towards this goal.

Testing some major determinants for hospital innovation success.

PubMed

Caccia-Bava, Maria do Carmo; Guimaraes, Valerie C K; Guimaraes, Tor

2009-01-01

Hospitals have adopted new policies, methods and technologies to change their processes, improve services, and support other organizational changes necessary for better performance. The literature regarding the four major areas of strategic leadership, competitive intelligence, management of technology, and specific characteristics of the organization's change process propose their importance in successfully implementing organization innovation. While these factors may indeed be important to enhance hospital performance, the existing literature contains limited empirical evidence supporting their relationship to successfully implementing innovation in hospitals. This study aims to empirically test these relationships proposed in the literature by researchers in separate knowledge areas. A survey of 223 hospitals has been used to test an integrated model of these relationships. The response rate and the representativeness of the sample in terms of hospital size and geographical location were found satisfactory. The quality assurance/compliance managers for each hospital were the target respondents to questions, which require a corporate perspective while reducing the chance of bias for questions regarding top management leadership abilities. The results provide clear evidence about the importance of strategic leadership, competitive intelligence, management of technology, and specific characteristics of the hospital's change process to the hospitals success in implementing innovation. Given the importance of hospitals to change their processes, improve services, and support other organizational changes necessary for better performance, a great benefit is that the main factors for successful innovation have been brought together from scattered literature and tested among hospitals. Further, the items used for measuring the main constructs provide further insights into how hospital administrators should go about developing these areas within their organizations. This study is a first attempt at empirically testing the importance of strategic leadership, competitive intelligence, management of technology, and specific characteristics of the hospital's change process for the success of innovation efforts.

Pumped storage system model and experimental investigations on S-induced issues during transients

NASA Astrophysics Data System (ADS)

Zeng, Wei; Yang, Jiandong; Hu, Jinhong

2017-06-01

Because of the important role of pumped storage stations in the peak regulation and frequency control of a power grid, pump turbines must rapidly switch between different operating modes, such as fast startup and load rejection. However, pump turbines go through the unstable S region in these transition processes, threatening the security and stability of the pumped storage station. This issue has mainly been investigated through numerical simulations, while field experiments generally involve high risks and are difficult to perform. Therefore, in this work, the model test method was employed to study S-induced security and stability issues for a pumped storage station in transition processes. First, a pumped storage system model was set up, including the piping system, model units, electrical control systems and measurement system. In this model, two pump turbines with different S-shaped characteristics were installed to determine the influence of S-shaped characteristics on transition processes. The model platform can be applied to simulate any hydraulic transition process that occurs in real power stations, such as load rejection, startup, and grid connection. On the experimental platform, the S-shaped characteristic curves were measured to be the basis of other experiments. Runaway experiments were performed to verify the impact of the S-shaped characteristics on the pump turbine runaway stability. Full load rejection tests were performed to validate the effect of the S-shaped characteristics on the water-hammer pressure. The condition of one pump turbine rejecting its load after another defined as one-after-another (OAA) load rejection was performed to validate the possibility of S-induced extreme draft tube pressure. Load rejection experiments with different guide vane closing schemes were performed to determine a suitable scheme to adapt the S-shaped characteristics. Through these experiments, the threats existing in the station were verified, the appropriate measures were summarized, and an important experimental basis for the safe and stable operation of a pumped storage station was provided.

Cultural characteristics of "high" and "low" performing hospitals.

PubMed

Mannion, R; Davies, H T O; Marshall, M N

2005-01-01

To compare and contrast the cultural characteristics of "high" and "low" performing hospitals in the UK National Health Service (NHS). A multiple case study design incorporating a purposeful sample of "low" and "high" performing acute hospital Trusts, as assessed by the star performance rating system. These case studies suggest that "high" and "low" performing acute hospital organisations may be very different environments in which to work. Although each case possessed its own unique character, significant patternings were observed within cases grouped by performance to suggest considerable cultural divergence. The key points of divergence can be grouped under four main headings: leadership and management orientation; accountability and information systems; human resources policies; and relationships within the local health economy. As with any study, interpretation of findings should be tempered with a degree of caution because of methodological considerations. First, there are the limitations of case study which proceeds on the basis of theoretical rather than quantitative generalisation. Second, organisational culture was assessed by exploring the views of middle and senior managers. While one should in no way suggest that such an approach can capture all important cultural characteristics of organisations, it is believed that it may be at least partially justified, given the agenda-setting powers and influence of the senior management team. Finally "star" performance measures are far from a perfect measure of organisational performance. Despite such reservations, the findings indicate that organisational culture is associated in a variety of non-trivial ways with the measured performance of hospital organisations. Highlights considerable cultural divergence within UK NHS hospitals.

Characteristics of coordinated ongoing comprehensive care within a medical home in Maine.

PubMed

Tippy, Kathy; Meyer, Katie; Aronson, Richard; Wall, Toni

2005-06-01

Access to coordinated, ongoing comprehensive care in a medical home (CCMH) is a national health objective and a federal performance measure. The National Survey of Children With Special Health Care Needs (National Survey of CSHCN) provides state level data on this Maternal Child Health Bureau performance measure. In Maine, only 60% of CSHCN received CCMH in 2001. Here we described characteristics of receiving comprehensive care in a medical home for CSHCN, in Maine. Data from the National Survey of CSHCN were used for the analysis. We examined associations between receiving CCMH and demographic factors, severity of a condition or problem, and having adequate insurance coverage for services in univariate and multivariate logistic regression models. The distribution of children who received CCMH did not differ across gender, race, age, or poverty level. Children with adequate insurance were more likely to have received this care than those without adequate insurance and those with a more severe condition or problem were less likely to receive CCMH. We found that receiving CCMH was positively related to adequate insurance, independent of poverty. We also found that CSHCN with more severe conditions have more unmet needs than those with less severe conditions. CSHCN programs, which have a responsibility to assure that CSHCN receive CCMH, must work to maximize insurance coverage. Programs can also work to raise awareness among providers of the complexity of CCMH and the role it plays in maximizing the health of the child and family.

Effect of piston profile on performance and emission characteristics of a GDI engine with split injection strategy - A CFD study

NASA Astrophysics Data System (ADS)

Karaya, Y.; Mallikarjuna, J. M.

2017-09-01

Gasoline direct injection (GDI) engines have gained popularity in the recent times because of lower fuel consumption and exhaust emissions. But in these engines, the mixture preparation plays an important role which affects combustion, performance and emission characteristics. The mixture preparation in turn depends mainly upon combustion chamber geometry. Therefore, in this study, an attempt has been made to understand the effect of piston profile on the performance and emission characteristics in a GDI engine. The analysis is carried out on a four-stroke wall guided GDI engine using computational fluid dynamics (CFD). The spray breakup model used is validated with the available experimental results from the literature to the extent possible. The analysis is carried out for four piston profiles viz., offset pentroof with offset bowl (OPOB), flat piston with offset bowl (FPOB), offset pentroof with offset scoop (OPOS) and inclined piston with offset bowl (IPOB) fitted in an engine equipped with a six-hole injector with the split injection ratio of 30:70. All the CFD simulations are carried out at the engine speed of 2000 rev/min., with the overall equivalence ratio of about 0.65±0.05. The performance and emission characteristics of the engine are compared while using the above piston profiles. It is found that, the OPOB piston is preferred compared to that of the other pistons because it has better in-cylinder flow, IMEP and lower HC emissions compared to that of other pistons.

Key fuel properties and engine performances of diesel-ethanol blends, using tetrahydrofuran as surfactant additive

NASA Astrophysics Data System (ADS)

Molea, A.; Visuian, P.; Barabás, I.; Suciu, R. C.; Burnete, N. V.

2017-10-01

In this paper there were presented researches related to preparation and characterization of physicochemical properties of diesel-ethanol blends stabilized with tetrahydrofuran as surfactant, in order to be used as fuels in compression ignition engines. The main spray characteristics and engine performances of these blends were evaluated by using AVL Fire software. In the first stage of the studies, commercial diesel was mixed with ethanol, in different concentrations (between 2% and 15% v/v), followed by the addition of tetrahydrofuran (THF) until the blends were miscible, i.e. the blends were stabilized. The experiments were done at room temperature (22 °C). The obtained blends were characterized in order to determine the chemical composition and physicochemical properties, i.e. density, kinematic viscosity, surface tension. UV-Vis spectroscopy was utilized in order to determine a semi-quantitative evaluation regarding the chemical composition of the prepared blends and chemical interaction between diesel, ethanol and THF. Based on the determined properties, the fuel spray characteristics, engine performances and emission characteristics were evaluated by simulation using the AVL Fire software. The obtained results regarding physicochemical properties of blends were compared with diesel. Some improvements were observed when operating with the prepared blends compared to diesel with respect to engine performances and emission characteristics. Based on physicochemical evaluation and computer simulation, it was demonstrated that diesel-ethanol-tetrahydrofuran blends can be used as alternative fuel in compression ignition engines.

Performance characteristics of mobile MOSFET dosimeter for kilovoltage X-rays used in image guided radiotherapy.

PubMed

Kumar, A Sathish; Singh, I Rabi Raja; Sharma, S D; Ravindran, B Paul

2015-01-01

The main objective of this study was to investigate the characteristics of metal oxide semiconductor field effect transistor (MOSFET) dosimeter for kilovoltage (kV) X-ray beams in order to perform the in vivo dosimetry during image guidance in radiotherapy. The performance characteristics of high sensitivity MOSFET dosimeters were investigated for 80, 90, 100, 110, 120, and 125 kV X-ray beams used for imaging in radiotherapy. This study was performed using Clinac 2100 C/D medical electron linear accelerator with on-board imaging and kV cone beam computed tomography system. The characteristics studied in this work include energy dependence, angular dependence, and linearity. The X-ray beam outputs were measured as per American Association of Physicists in Medicine (AAPM) TG 61 recommendations using PTW parallel plate (PP) ionization chamber, which was calibrated in terms of air kerma (Nk) by the National Standard Laboratory. The MOSFET dosimeters were calibrated against the PP ionization chamber for all the kV X-ray beams and the calibration coefficient was found to be 0.11 cGy/mV with a standard deviation of about ±1%. The response of MOSFET was found to be energy independent for the kV X-ray energies used in this study. The response of the MOSFET dosimeter was also found independent of angle of incidence for the gantry angles in the range of 0° to 360° in-air as well as at 3 cm depth in tissue equivalent phantom.

Evaluation of multispectral plenoptic camera

NASA Astrophysics Data System (ADS)

Meng, Lingfei; Sun, Ting; Kosoglow, Rich; Berkner, Kathrin

2013-01-01

Plenoptic cameras enable capture of a 4D lightfield, allowing digital refocusing and depth estimation from data captured with a compact portable camera. Whereas most of the work on plenoptic camera design has been based a simplistic geometric-optics-based characterization of the optical path only, little work has been done of optimizing end-to-end system performance for a specific application. Such design optimization requires design tools that need to include careful parameterization of main lens elements, as well as microlens array and sensor characteristics. In this paper we are interested in evaluating the performance of a multispectral plenoptic camera, i.e. a camera with spectral filters inserted into the aperture plane of the main lens. Such a camera enables single-snapshot spectral data acquisition.1-3 We first describe in detail an end-to-end imaging system model for a spectrally coded plenoptic camera that we briefly introduced in.4 Different performance metrics are defined to evaluate the spectral reconstruction quality. We then present a prototype which is developed based on a modified DSLR camera containing a lenslet array on the sensor and a filter array in the main lens. Finally we evaluate the spectral reconstruction performance of a spectral plenoptic camera based on both simulation and measurements obtained from the prototype.

Investigation of hollow cathode performance for 30-cm thrusters

NASA Technical Reports Server (NTRS)

Mirtich, M. J.

1973-01-01

A parametric investigation of 6.35 mm diameter mercury hollow cathodes was carried out in a bell jar. The parameters that were varied were the amount of initial emissive mix, insert position, emission current, cathode temperature, orifice diameter, and mercury flow rate. Flow characteristic curves and performance as a function of time were obtained for the various cathodes. The results of a 3880 hr life test of a main cathode run at 15 amps emission current with no noticeable changes in keeper and collector voltages are also presented.

The Landsat Data Continuity Mission Operational Land Imager: Pre-Launch Performance

NASA Technical Reports Server (NTRS)

Markham, Brian L.; Knight, Edward J.; Canova, Brent; Donley, Eric; Kvaran, Geir; Lee, Kenton

2011-01-01

The Operational Land Imager(OLI) will be the main instrument on Landsat-8 when it launches in 2012. OLI represents a generational change from heritage Landsat instruments in its design but must maintain data continuity with the 30+ year Landsat data archive. As a result, OLI has undergone a stringent calibration and characterization campaign to ensure its characteristics are understood and consistent with past instruments. This paper presents an overview of the OLI design, its major differences from previous Landsat instruments, and a summary of its expected performance.

Comparison of display enhancement with intelligent decision-aiding

NASA Technical Reports Server (NTRS)

Kirlik, Alex; Markert, Wendy J.; Kossack, Merrick

1992-01-01

Currently, two main approaches exist for improving the human-machine interface component of a system in order to improve overall system performance, display enhancement and intelligent decision aiding. Each of these two approaches has its own set of advantages and disadvantages, as well as introduce its own set of additional performance problems. These characteristics should help identify which types of problem situations and domains are better aided by which type of strategy. The characteristic issues are described of these two decision aiding strategies. Then differences in expert and novice decision making are described in order to help determine whether a particular strategy may be better for a particular type of user. Finally, research is outlined to compare and contrast the two technologies, as well as to examine the interaction effects introduced by the different skill levels and the different methods for training operators.

[Selection criteria of mobile lifters in the hospital setting].

PubMed

Ferriero, G; Ottonello, M; Franchignoni, F

2002-01-01

The manual handling of patients with limited mobility represents the major cause of musculoskeletal injury to the spine in paramedical health care workers. Within the hospital, the more complex procedures of patient transfer often require the use of mobile hoists. The aim of this paper is to describe the basic criteria for the selection of such hoists. The main characteristics of a hoist are its stability, the sling attachment, the speed of operation, range of movement of the spreader bar, safety of the operation being performed, patient comfort, the physical effort required on the part of the health care worker, manoeuvrability and simplicity of use. Important organizational-structural features to evaluate include: the type of patient normally present in the unit concerned, the specific movement to be performed, the structural characteristics of the environment, and the work organization of the personnel.

Effect of micro-scale texturing on the cutting tool performance

NASA Astrophysics Data System (ADS)

Vasumathy, D.; Meena, Anil

2018-05-01

The present study is mainly focused on the cutting performance of the micro-scale textured carbide tools while turning AISI 304 austenitic stainless steel under dry cutting environment. The texture on the rake face of the carbide tools was fabricated by laser machining. The cutting performance of the textured tools was further compared with conventional tools in terms of cutting forces, tool wear, machined surface quality and chip curl radius. SEM and EDS analyses have been also performed to better understand the tool surface characteristics. Results show that the grooves help in breaking the tool-chip contact leading to a lesser tool-chip contact area which results in reduced iron (Fe) adhesion to the tool.

Academic Job Placements in Library and Information Science Field: A Case Study Performed on ALISE Web-Based Postings

ERIC Educational Resources Information Center

Abouserie, Hossam Eldin Mohamed Refaat

2010-01-01

The study investigated and analyzed the state of academic web-based job announcements in Library and Information Science Field. The purpose of study was to get in depth understanding about main characteristics and trends of academic job market in Library and Information science field. The study focused on web-based version announcement as it was…

Depolarization on Earth-space paths

NASA Technical Reports Server (NTRS)

1981-01-01

Sources of depolarization effects on the propagation paths of orthogonally-polarized information channels are considered. The main sources of depolarization at millimeter wave frequencies are hydrometeor absorption and scattering in the troposphere. Terms are defined. Mathematical formulations for the effects of the propagation medium characteristics and antenna performance on signals in dual polarization Earth-space links are presented. Techniques for modeling rain and ice depolarization are discussed.

Development of a high resolution stepper motor prototype. volume 1: general presentation. Final report

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

Not Available

1975-12-01

This motor could be used to drive large solar panels of future satellites. Its main performance characteristics are as follows: 1,200 steps per revolution, relaxation torque greater than 0.3 mN, holding torque greater than 1mN, and input power at full torque less than 1.5 W. For volume 2 and 3; see ESR-97067. (GRA)

Performances and first science results with the VEGA/CHARA visible instrument

NASA Astrophysics Data System (ADS)

Mourard, D.; Tallon, M.; Bério, Ph.; Bonneau, D.; Chesneau, O.; Clausse, J. M.; Delaa, O.; Nardetto, N.; Perraut, K.; Spang, A.; Stee, Ph.; Tallon-Bosc, I.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

2010-07-01

This paper presents the current status of the VEGA (Visible spEctroGraph and polArimeter) instrument installed at the coherent focus of the CHARA Array, Mount Wilson CA. Installed in september 2007, the first science programs have started during summer 2008 and first science results are now published. Dedicated to high angular (0.3mas) and high spectral (R=30000) astrophysical studies, VEGA main objectives are the study of circumstellar environments of hot active stars or interactive binary systems and a large palette of new programs dedicated to fundamental stellar parameters. We will present successively the main characteristics of the instrument and its current performances in the CHARA environment, a short summary of two science programs and finally we will develop some studies showing the potential and difficulties of the 3 telescopes mode of VEGA/CHARA.

Physics issues in diffraction limited storage ring design

NASA Astrophysics Data System (ADS)

Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

2012-05-01

Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

Slim Battery Modelling Features

NASA Astrophysics Data System (ADS)

Borthomieu, Y.; Prevot, D.

2011-10-01

Saft has developed a life prediction model for VES and MPS cells and batteries. The Saft Li-ion Model (SLIM) is a macroscopic electrochemical model based on energy (global at cell level). The main purpose is to predict the battery performances during the life for GEO, MEO and LEO missions. This model is based on electrochemical characteristics such as Energy, Capacity, EMF, Internal resistance, end of charge voltage. It uses fading and calendar law effects on energy and internal impedance vs. time, temperature, End of Charge voltage. Based on the mission profile, satellite power system characteristics, the model proposes the various battery configurations. For each configuration, the model gives the battery performances using mission figures and profiles: power, duration, DOD, end of charge voltages, temperatures during eclipses and solstices, thermal dissipations and cell failures. For the GEO/MEO missions, eclipse and solstice periods can include specific profile such as plasmic propulsion fires and specific balancing operations. For LEO missions, the model is able to simulate high power peaks to predict radar pulses. Saft's main customers have been using the SLIM model available in house for two years. The purpose is to have the satellite builder power engineers able to perform by themselves in the battery pre-dimensioning activities their own battery simulations. The simulations can be shared with Saft engineers to refine the power system designs. This model has been correlated with existing life and calendar tests performed on all the VES and MPS cells. In comparing with more than 10 year lasting life tests, the accuracy of the model from a voltage point of view is less than 10 mV at end Of Life. In addition, thethe comparison with in-orbit data has been also done. b This paper will present the main features of the SLIM software and outputs comparison with real life tests. b0

2007 international meeting on Reduced Enrichment for Research and Test Reactors (RERTR). Abstracts and available papers presented at the meeting

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

NONE

2008-07-15

The Meeting papers discuss research and test reactor fuel performance, manufacturing and testing. Some of the main topics are: conversion from HEU to LEU in different reactors and corresponding problems and activities; flux performance and core lifetime analysis with HEU and LEU fuels; physics and safety characteristics; measurement of gamma field parameters in core with LEU fuel; nondestructive analysis of RERTR fuel; thermal hydraulic analysis; fuel interactions; transient analyses and thermal hydraulics for HEU and LEU cores; microstructure research reactor fuels; post irradiation analysis and performance; computer codes and other related problems.

Study on seismic performance of BFRP geogrid reinforced Tibetan rubble wall

NASA Astrophysics Data System (ADS)

Yang, Dan; Jia, Bin; Huang, Hui; Deng, Chuangli

2018-03-01

For the study of BFRP geogrid influence on Tibetan rubble wall seismic performance, in this paper, on the premise of not change the way of traditional masonry, laying and not join geogrid respectively on the the rubble wall, and carries on the cyclic loading experiment on them. The damage characteristics, crack width and seismic performance of the rubble walls with BFRP geogrid are studied. The experimental results show that the deformation of the rubble wall is mainly the shear deformation under the action of horizontal force, and the bearing capacity and energy dissipation capacity of the wall can be improved significantly after joining the geogrid.

Influence of quality of care and individual patient characteristics on quality of life and return to work in survivors of the acute respiratory distress syndrome: protocol for a prospective, observational, multi-centre patient cohort study (DACAPO).

PubMed

Brandstetter, Susanne; Dodoo-Schittko, Frank; Blecha, Sebastian; Sebök, Philipp; Thomann-Hackner, Kathrin; Quintel, Michael; Weber-Carstens, Steffen; Bein, Thomas; Apfelbacher, Christian

2015-12-17

Health-related quality of life (HRQoL) and return to work are important outcomes in critical care medicine, reaching beyond mortality. Little is known on factors predictive of HRQoL and return to work in critical illness, including the acute respiratory distress syndrome (ARDS), and no evidence exists on the role of quality of care (QoC) for outcomes in survivors of ARDS. It is the aim of the DACAPO study ("Surviving ARDS: the influence of QoC and individual patient characteristics on quality of life") to investigate the role of QoC and individual patient characteristics on quality of life and return to work. A prospective, observational, multi-centre patient cohort study will be performed in Germany, using hospitals from the "ARDS Network Germany" as the main recruiting centres. It is envisaged to recruit 2400 patients into the DACAPO study and to analyse a study population of 1500 survivors. They will be followed up until 12 months after discharge from hospital. QoC will be assessed as process quality, structural quality and volume at the institutional level. The main outcomes (HRQoL and return to work) will be assessed by self-report questionnaires. Further data collection includes general medical and ARDS-related characteristics of patients as well as sociodemographic and psycho-social parameters. Multilevel hierarchical modelling will be performed to analyse the effects of QoC and individual patient characteristics on outcomes, taking the cluster structure of the data into account. By obtaining comprehensive data at patient and hospital level using a prospective multi-centre design, the DACAPO-study is the first study investigating the influence of QoC on individual outcomes of ARDS survivors.

CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge

NASA Astrophysics Data System (ADS)

Qiu, Yi Mei; Wen, Sen Yuan; Chen, Jun Xiang

2018-06-01

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

PubMed

Karthikeya Sharma, T

2015-11-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

PubMed Central

Karthikeya Sharma, T.

2014-01-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied. PMID:26644918

Explosion characteristics of LPG-air mixtures in closed vessels.

PubMed

Razus, Domnina; Brinzea, Venera; Mitu, Maria; Oancea, D

2009-06-15

The experimental study of explosive combustion of LPG (liquefied petroleum gas)-air mixtures at ambient initial temperature was performed in two closed vessels with central ignition, at various total initial pressures within 0.3-1.3bar and various fuel/air ratios, within the flammability limits. The transient pressure-time records were used to determine several explosion characteristics of LPG-air: the peak explosion pressure, the explosion time (the time necessary to reach the peak pressure), the maximum rate of pressure rise and the severity factor. All explosion parameters are strongly dependent on initial pressure of fuel-air mixture and on fuel/air ratio. The explosion characteristics of LPG-air mixtures are discussed in comparison with data referring to the main components of LPG: propane and butane, obtained in identical conditions.

Plasma metallurgical production of nanocrystalline borides and carbides

NASA Astrophysics Data System (ADS)

Galevsky, G. V.; Rudneva, V. V.; Cherepanov, A. N.; Galevsky, S. G.; Efimova, K. A.

2016-09-01

he experience in production and study of properties of nanocrystalline borides and chromium carbides, titanium, silicon was summarized. The design and features of the vertical three-jet once-through reactor with power 150 kW, used in the plasma metallurgical production, was described. The technological, thermotechnical and resource characteristics of the reactor were identified. The parameters of borides and carbides synthesis, their main characteristics in the nanodispersed state and equipment-technological scheme of production were provided. Evaluation of engineering-and-economical performance of the laboratory and industrial levels of borides and carbides production and the state corresponding to the segment of the world market was carried out.

Imitative modeling automatic system Control of steam pressure in the main steam collector with the influence on the main Servomotor steam turbine

NASA Astrophysics Data System (ADS)

Andriushin, A. V.; Zverkov, V. P.; Kuzishchin, V. F.; Ryzhkov, O. S.; Sabanin, V. R.

2017-11-01

The research and setting results of steam pressure in the main steam collector “Do itself” automatic control system (ACS) with high-speed feedback on steam pressure in the turbine regulating stage are presented. The ACS setup is performed on the simulation model of the controlled object developed for this purpose with load-dependent static and dynamic characteristics and a non-linear control algorithm with pulse control of the turbine main servomotor. A method for tuning nonlinear ACS with a numerical algorithm for multiparametric optimization and a procedure for separate dynamic adjustment of control devices in a two-loop ACS are proposed and implemented. It is shown that the nonlinear ACS adjusted with the proposed method with the regulators constant parameters ensures reliable and high-quality operation without the occurrence of oscillations in the transient processes the operating range of the turbine loads.

Research pressure instrumentation for NASA Space Shuttle main engine, modification no. 5

NASA Technical Reports Server (NTRS)

Anderson, P. J.; Nussbaum, P.; Gustafson, G.

1984-01-01

The objective of the research project described is to define and demonstrate methods to advance the state of the art of pressure sensors for the space shuttle main engine (SSME). Silicon piezoresistive technology was utilized in completing tasks: generation and testing of three transducer design concepts for solid state applications; silicon resistor characterization at cryogenic temperatures; experimental chip mounting characterization; frequency response optimization and prototype design and fabrication. Excellent silicon sensor performance was demonstrated at liquid nitrogen temperature. A silicon resistor ion implant dose was customized for SSME temperature requirements. A basic acoustic modeling software program was developed as a design tool to evaluate frequency response characteristics.

Design considerations for a Space Shuttle Main Engine turbine blade made of single crystal material

NASA Technical Reports Server (NTRS)

Abdul-Aziz, A.; August, R.; Nagpal, V.

1993-01-01

Nonlinear finite-element structural analyses were performed on the first stage high-pressure fuel turbopump blade of the Space Shuttle Main Engine. The analyses examined the structural response and the dynamic characteristics at typical operating conditions. Single crystal material PWA-1480 was considered for the analyses. Structural response and the blade natural frequencies with respect to the crystal orientation were investigated. The analyses were conducted based on typical test stand engine cycle. Influence of combined thermal, aerodynamic, and centrifugal loadings was considered. Results obtained showed that the single crystal secondary orientation effects on the maximum principal stresses are not highly significant.

Groupwise connectivity-based parcellation of the whole human cortical surface using watershed-driven dimension reduction.

PubMed

Lefranc, Sandrine; Roca, Pauline; Perrot, Matthieu; Poupon, Cyril; Le Bihan, Denis; Mangin, Jean-François; Rivière, Denis

2016-05-01

Segregating the human cortex into distinct areas based on structural connectivity criteria is of widespread interest in neuroscience. This paper presents a groupwise connectivity-based parcellation framework for the whole cortical surface using a new high quality diffusion dataset of 79 healthy subjects. Our approach performs gyrus by gyrus to parcellate the whole human cortex. The main originality of the method is to compress for each gyrus the connectivity profiles used for the clustering without any anatomical prior information. This step takes into account the interindividual cortical and connectivity variability. To this end, we consider intersubject high density connectivity areas extracted using a surface-based watershed algorithm. A wide validation study has led to a fully automatic pipeline which is robust to variations in data preprocessing (tracking type, cortical mesh characteristics and boundaries of initial gyri), data characteristics (including number of subjects), and the main algorithmic parameters. A remarkable reproducibility is achieved in parcellation results for the whole cortex, leading to clear and stable cortical patterns. This reproducibility has been tested across non-overlapping subgroups and the validation is presented mainly on the pre- and postcentral gyri. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Analysis of Slab-column Shearwall Structure of 6000 Tons Cold Storage

NASA Astrophysics Data System (ADS)

He, Dongqing; Song, Pengwei; Jie, Pengyu

2018-05-01

Combining with the functional requirements, the site conditions and the 6000 tons load characteristics of cold storage, so determine its structure system for the slab-column-shear wall structure. The paper recommends the design of foundation, the settings of column cap, the arrangement of shear wall, the punching shear of floor slab and the analysis and calculation results of main structure. By addition shear wall in slab-column structure to increase the overall stiffness of structure and improve the seismic performance of structure. Take the detached form between the main structure and the external wall insulation, while set anchorage beam between in the main floor and the ring beam along the axis of the column grid to enhance the overall stability of the external wall insulation.

Success Factors of European Syndromic Surveillance Systems: A Worked Example of Applying Qualitative Comparative Analysis

PubMed Central

Ziemann, Alexandra; Fouillet, Anne; Brand, Helmut; Krafft, Thomas

2016-01-01

Introduction Syndromic surveillance aims at augmenting traditional public health surveillance with timely information. To gain a head start, it mainly analyses existing data such as from web searches or patient records. Despite the setup of many syndromic surveillance systems, there is still much doubt about the benefit of the approach. There are diverse interactions between performance indicators such as timeliness and various system characteristics. This makes the performance assessment of syndromic surveillance systems a complex endeavour. We assessed if the comparison of several syndromic surveillance systems through Qualitative Comparative Analysis helps to evaluate performance and identify key success factors. Materials and Methods We compiled case-based, mixed data on performance and characteristics of 19 syndromic surveillance systems in Europe from scientific and grey literature and from site visits. We identified success factors by applying crisp-set Qualitative Comparative Analysis. We focused on two main areas of syndromic surveillance application: seasonal influenza surveillance and situational awareness during different types of potentially health threatening events. Results We found that syndromic surveillance systems might detect the onset or peak of seasonal influenza earlier if they analyse non-clinical data sources. Timely situational awareness during different types of events is supported by an automated syndromic surveillance system capable of analysing multiple syndromes. To our surprise, the analysis of multiple data sources was no key success factor for situational awareness. Conclusions We suggest to consider these key success factors when designing or further developing syndromic surveillance systems. Qualitative Comparative Analysis helped interpreting complex, mixed data on small-N cases and resulted in concrete and practically relevant findings. PMID:27182731

Success Factors of European Syndromic Surveillance Systems: A Worked Example of Applying Qualitative Comparative Analysis.

PubMed

Ziemann, Alexandra; Fouillet, Anne; Brand, Helmut; Krafft, Thomas

2016-01-01

Syndromic surveillance aims at augmenting traditional public health surveillance with timely information. To gain a head start, it mainly analyses existing data such as from web searches or patient records. Despite the setup of many syndromic surveillance systems, there is still much doubt about the benefit of the approach. There are diverse interactions between performance indicators such as timeliness and various system characteristics. This makes the performance assessment of syndromic surveillance systems a complex endeavour. We assessed if the comparison of several syndromic surveillance systems through Qualitative Comparative Analysis helps to evaluate performance and identify key success factors. We compiled case-based, mixed data on performance and characteristics of 19 syndromic surveillance systems in Europe from scientific and grey literature and from site visits. We identified success factors by applying crisp-set Qualitative Comparative Analysis. We focused on two main areas of syndromic surveillance application: seasonal influenza surveillance and situational awareness during different types of potentially health threatening events. We found that syndromic surveillance systems might detect the onset or peak of seasonal influenza earlier if they analyse non-clinical data sources. Timely situational awareness during different types of events is supported by an automated syndromic surveillance system capable of analysing multiple syndromes. To our surprise, the analysis of multiple data sources was no key success factor for situational awareness. We suggest to consider these key success factors when designing or further developing syndromic surveillance systems. Qualitative Comparative Analysis helped interpreting complex, mixed data on small-N cases and resulted in concrete and practically relevant findings.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis.

PubMed

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin

2015-01-01

Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric-differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175-300°C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prevalence trends of wood use as the main cooking fuel in Mexico, 1990-2013.

PubMed

Hernández-Garduño, Eduardo; Gómez-García, Eva; Campos-Gómez, Saúl

2017-01-01

To determine prevalence trends of using Wood as the Main Cooking Fuel (WMCF) in Mexico and household characteristics that predict its use. Estimates were obtained from the 1990, 2000 and 2010 censuses and from a national survey performed in 2012 and 2013. In 2012-2013, 9.5% of the 66 321 surveyed households and 10.9% of their 252 011 residents used WMCF. Prevalence was higher in rural (40.5%) than urban areas (1.5%), p<0.0001. From 1990 to 2013 wood use decreased by 53% overall and by 28.6% in rural areas, gas use increased respectively by 17.5 and 52.7%. Predictors of using WMCF were living in rural or suburban areas and those associated with low socioeconomic status. Use of WMCF has decreased substantially in Mexico but at a slower pace in rural areas. Improving household characteristics and socioeconomic status may decrease use of WMCF at a higher rate.

Flavonoids function as antioxidants: By scavenging reactive oxygen species or by chelating iron?

NASA Astrophysics Data System (ADS)

Wuguo, Deng; Xingwang, Fang; Jilan, Wu

1997-09-01

Flavonoids have been reported to exhibit strong antioxidative activity. In the present work, a systematic mechanistic study has been performed on five flavonoids (baicalin, hesperidin, naringin, quercetin and rutin) selected according to their structural characteristics. The experimental results reveal that flavonoids function as antioxidant mainly by chelating iron ions and by scavenging peroxyl radicals whereas their OH radical scavenging effect is much less important.

Abstracts of ARI Research Publications, FY 1978

DTIC Science & Technology

1980-09-01

initial item pool, 49 items were identified as having signifi- cant item-to-total-score correlations and were statistically determined to address a...failing. Differences among the three groups on main gun performance measures and the previous experience of gun- ners were not statistically significant...forms of the noncognitive cod- ing speed test; and (d) a second field administration to derive norms and other statistical characteristics of the new

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

NASA Astrophysics Data System (ADS)

Varshnay, N. K.; Singh, A.; Benerji, N. S.

2017-02-01

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

CLINICAL DEMOGRAPHIC CHARACTERISTICS OF TOTAL KNEE ARTHROPLASTY IN A UNIVERSITY HOSPITAL

PubMed Central

Souza, José Miguel Francisco da Silva; Ferreira, Ricardo dos Santos; de Lima, Alexandre José Pereira; de Sá, Airton César Pereira; de Albuquerque, Paulo Cezar Vidal Carneiro

2016-01-01

ABSTRACT Objective: To assess socio-demographic characteristics of patients undergoing total knee arthroplasty (TKA) in a public university hospital, evaluating the outcome infection and associated factors. Method: A retrospective study was carried out with 78 patients undergoing TKA, from 2013 to 2014. The socio-demographic and clinical characteristics of the patients were collected. Comparison between infected and non-infected patients was performed to find out which variables were possibly associated to this complication. Result: Of 81 arthroplasties performed, patients were older (mean age 64 years), women (79%), with primary osteoarthritis as main etiology (87.6%) and most had comorbidities (82.7%). Infection occurred in 16% of patients, and this outcome associated with age older than 65 years (p=0.023) and the occurrence of deep vein thrombosis (p=0.027). Conclusion: Patients undergoing TKA are mostly elderly women with primary osteoarthritis in the knee and comorbidities who developed infection in 16% of cases. More studies need to be conducted aimed at creating specific protocols in order to improve the quality of clinical practice. Level of Evidence III, Retrospective Comparative Study. PMID:28924354

Modeling and characteristic of the SMT Board Plug connector in high speed optical communication system

NASA Astrophysics Data System (ADS)

Wu, Haoran; Dong, Zhenzhen; Wang, Tanglin; Zhao, Heng; Feng, Junbo; Cui, Naidi; Teng, Jie; Guo, Jin

2015-04-01

Modeling and characteristic of the SMT Board Plug connector, which is used to connect micro optical transceiver to the main board, are proposed and analyzed in this paper. When the high speed signal transfers from the PCB of transceiver to main board through SMT Board Plug connector, the structure and material discontinuity of the connector causes insertion losses and impedance mismatches. This makes the performance of high speed digital system exacerbated. So it is essential to analyze the signal transfer characteristics of the connector and find out what factors affected the signal quality at the design stage of the digital system. To solve this problem, Ansoft's High Frequency Structure Simulator (HFSS), based on the finite element method, was employed to build accurate 3D models, analyze the effects of various structure parameters, and obtain the full-wave characteristics of the SMT Board Plug connectors in this paper. Then an equivalent circuit model was developed. The circuit parameters were extracted precisely in the frequency range of interests by using the curve fitting method in ADS software, and the result was in good agreement with HFSS simulations up to 8GHz with different structure parameters. At last, the measurement results of S-parameter and eye diagram were given and the S-parameters showed good coincidence between the measurement and HFSS simulation up to 4GHz.

Flow Field Characteristics and Lift Changing Mechanism for Half-Rotating Wing in Hovering Flight

NASA Astrophysics Data System (ADS)

Li, Q.; Wang, X. Y.; Qiu, H.; Li, C. M.; Qiu, Z. Z.

2017-12-01

Half-rotating wing (HRW) is a new similar-flapping wing system based on half-rotating mechanism which could perform rotating-type flapping instead of oscillating-type flapping. The characteristics of flow field and lift changing mechanism for HRW in hovering flight are important theoretical basis to improve the flight capability of HRW aircraft. The driving mechanism and work process of HRW were firstly introduced in this paper. Aerodynamic simulation model of HRW in hovering flight was established and solved using XFlow software, by which lift changing rule of HRW was drawn from the simulation solution. On the other hand, the development and shedding of the distal vortex throughout one stroke would lead to the changes of the lift force. Based on analyzing distribution characteristics of vorticity, velocity and pressure around wing blade, the main features of the flow field for HRW were further given. The distal attached vortex led to the increase of the lift force, which would gradually shed into the wake with a decline of lift in the later downstroke. The wake ring directed by the distal end of the blade would generate the downward accelerating airflow which produced the upward anti-impulse to HRW. The research results mentioned above illustrated that the behavior characteristics of vortex formed in flow field were main cause of lift changing for HRW.

Development and experimental characterization of a new non contact sensor for blade tip timing

NASA Astrophysics Data System (ADS)

Brouckaert, Jean-Francois; Marsili, Roberto; Rossi, Gianluca; Tomassini, Roberto

2012-06-01

Performances of blade tip timing measurement systems (BTT), recently used for non contact turbine blade vibration measurements, in terms of uncertainty and resolution are strongly affected by sensor characteristics. The sensors used for BTT generate pulses, to be used also for precise measurements of turbine blades time of arrival. All the literature on this measurement techniques do not address this problem in a clear way, defining the relevant dynamic and static sensor characteristics, fundamental for this application. Till now proximity sensors used are based on optical, capacitive, eddy current and microwave measuring principle. Also pressure sensors has been used. In this paper a new sensing principle is proposed. A proximity sensor based on magnetoresistive sensing element has been assembled end tested. A simple and portable test bench with variable speed, blade tip width, variable clearance was built and used in order to characterize the main sensor performances.

Transmutation of Radioactive Nuclear Waste — Present Status and Requirement for the Problem-Oriented Nuclear Database: Approach to Scheduling the Experiments (Reactor, Target, Blanket)

NASA Astrophysics Data System (ADS)

Artisyuk, V.; Ignatyuk, A.; Korovin, Yu.; Lopatkin, A.; Matveenko, I.; Stankovskiy, A.; Titarenko, Yu.

2005-05-01

Transmutation of nuclear wastes (Minor Actinides and Long-Lived Fission Products) remains an important option to reduce the burden of high-level waste on final waste disposal in deep geological structures. Accelerator-Driven Systems (ADS) are considered as possible candidates to perform transmutation due to their subcritical operation mode that eliminates some of the serious safety penalties unavoidable in critical reactors. Specific requirements to nuclear data necessary for ADS transmutation analysis is the main subject of the ISTC Project ♯2578 which started in 2004 to identify the areas of research priorities in the future. The present paper gives a summary of ongoing project stressing the importance of nuclear data for blanket performance (reactivity behavior with associated safety characteristics) and uncertainties that affect characteristics of neutron producing target.

Real Gas Computation Using an Energy Relaxation Method and High-Order WENO Schemes

NASA Technical Reports Server (NTRS)

Montarnal, Philippe; Shu, Chi-Wang

1998-01-01

In this paper, we use a recently developed energy relaxation theory by Coquel and Perthame and high order weighted essentially non-oscillatory (WENO) schemes to simulate the Euler equations of real gas. The main idea is an energy decomposition into two parts: one part is associated with a simpler pressure law and the other part (the nonlinear deviation) is convected with the flow. A relaxation process is performed for each time step to ensure that the original pressure law is satisfied. The necessary characteristic decomposition for the high order WENO schemes is performed on the characteristic fields based on the first part. The algorithm only calls for the original pressure law once per grid point per time step, without the need to compute its derivatives or any Riemann solvers. Both one and two dimensional numerical examples are shown to illustrate the effectiveness of this approach.

Light, sound, chemistry… action: state of the art optical methods for animal imaging.

PubMed

Ripoll, Jorge; Ntziachristos, Vasilis

2011-01-01

During recent years, macroscopic optical methods have been promoted from backstage to main actors in biological imaging. Many possible forms of energy conservation have been explored that involve light, including fluorescence emission, sound generated through absorption and bioluminescence, that is light generated through a chemical reaction. These physicochemical approaches for contrast generation have resulted in optical imaging methods that come with potent performance characteristics over simple epi-illumination optical imaging approaches of the past, and can play a central role in imaging applications in vivo as it pertains to modern biological and drug discovery, pre-clinical imaging and clinical applications. This review focuses on state of the art optical and opto-acoustic (photo-acoustic) imaging methods and discusses key performance characteristics that convert optical imaging from a qualitative modality to a powerful high-resolution and quantitative volumetric interrogation tool for operation through several millimeters of tissue depth.: © 2011 Elsevier Ltd . All rights reserved.

Full-Scale Investigation of Aerodynamic Characteristics of a Typical Single-Sotor Helicopter in Forward Flight

NASA Technical Reports Server (NTRS)

Dingeldein, Richard C; Schaefer, Raymond F

1948-01-01

As part of the general helicopter research program being undertaken by the National Advisory Committee for Aeronautics to provide designers with fundamental rotor information, the forward-flight performance characteristics of a typical single-rotor helicopter, which is equipped with main and tail rotors, have been investigated in the Langley full-scale tunnel. The test conditions included operation of tip-speed ratios from 0.10 to 0.27 and at thrust coefficients from 0.0030 to 0.0060. Results obtained with production rotor were compared with those for an alternate set of blades having closer rib spacing and a smoother and more accurately contoured surface in order to evaluate the performance gains that are available by the use of rotor blades having an improved surface condition. The wind tunnel results are shown to be in fair agreement with the results of both flight tests and theoretical predictions.

Self-shielded electron linear accelerators designed for radiation technologies

NASA Astrophysics Data System (ADS)

Belugin, V. M.; Rozanov, N. E.; Pirozhenko, V. M.

2009-09-01

This paper describes self-shielded high-intensity electron linear accelerators designed for radiation technologies. The specific property of the accelerators is that they do not apply an external magnetic field; acceleration and focusing of electron beams are performed by radio-frequency fields in the accelerating structures. The main characteristics of the accelerators are high current and beam power, but also reliable operation and a long service life. To obtain these characteristics, a number of problems have been solved, including a particular optimization of the accelerator components and the application of a variety of specific means. The paper describes features of the electron beam dynamics, accelerating structure, and radio-frequency power supply. Several compact self-shielded accelerators for radiation sterilization and x-ray cargo inspection have been created. The introduced methods made it possible to obtain a high intensity of the electron beam and good performance of the accelerators.

A dynamic quality assessment tool for laparoscopic hysterectomy to measure surgical outcomes.

PubMed

Driessen, Sara R C; Van Zwet, Erik W; Haazebroek, Pascal; Sandberg, Evelien M; Blikkendaal, Mathijs D; Twijnstra, Andries R H; Jansen, Frank Willem

2016-12-01

The current health care system has an urgent need for tools to measure quality. A wide range of quality indicators have been developed in an attempt to differentiate between high-quality and low-quality health care processes. However, one of the main issues of currently used indicators is the lack of case-mix correction and improvement possibilities. Case-mix is defined as specific (patient) characteristics that are known to potentially affect (surgical) outcome. If these characteristics are not taken into consideration, comparisons of outcome among health care providers may not be valid. The objective of the study was to develop and test a quality assessment tool for laparoscopic hysterectomy, which can serve as a new outcome quality indicator. This is a prospective, international, multicenter implementation study. A web-based application was developed with 3 main goals: (1) to measure the surgeon's performance using 3 primary outcomes (blood loss, operative time, and complications); (2) to provide immediate individual feedback using cumulative observed-minus-expected graphs; and (3) to detect consistently suboptimal performance after correcting for case-mix characteristics. All gynecologists who perform laparoscopic hysterectomies were requested to register their procedures in the application. A patient safety risk factor checklist was used by the surgeon for reflection. Thereafter a prospective implementation study was performed, and the application was tested using a survey that included the System Usability Scale. A total of 2066 laparoscopic hysterectomies were registered by 81 gynecologists. Mean operative time was 100 ± 39 minutes, blood loss 127 ± 163 mL, and the complication rate 6.1%. The overall survey response rate was 75%, and the mean System Usability Scale was 76.5 ± 13.6, which indicates that the application was good to excellent. The majority of surgeons reported that the application made them more aware of their performance, the outcomes, and patient safety, and they noted that the application provided motivation for improving future performance. We report the development and test of a real-time, dynamic, quality assessment tool for measuring individual surgical outcome for laparoscopic hysterectomy. Importantly, this tool provides opportunities for improving surgical performance. Our study provides a foundation for helping clinicians develop evidence-based quality indicators for other surgical procedures. Copyright © 2016 Elsevier Inc. All rights reserved.

Pulmonary embolism: epidemiological data and diagnosis in Kinshasa hospitals.

PubMed

Bakebe, A; Kashongwe, I; Mulenga, C; Tshiasuma, M; Kabengele, B; Bisuta, S F; Makulo, J R; Kashongwe, Z; Kayembe, J-M

2017-08-01

Pulmonary embolism (PE) is common but difficult to diagnose. To describe the epidemiological, clinical and paraclinical characteristics of PE in Kinshasa hospitals. This was a retrospective study in 158 cases with suspected PE. The prevalence of PE was 37% among cases with suspicion of the disease. Male sex was predominant (55%). The mean age was 55 ± 15 years. The main risk factors were obesity (53%), immobilisation (43%) and surgery (14%). The main symptoms were dyspnoea (98%), cough (59%), chest pain (43%) and unilateral limb pain (36%). Tachypnoea (88%), tachycardia (53%) and signs of deep-vein thrombosis (36%) were the main clinical presentations. Lung examination was normal in 55% of the patients. PE prevalence in the 'PE likely' category based on the Wells score was 53%. Levels of D-dimers were elevated in all patients. Sinus tachycardia (72%), S1Q3T3 pattern (30%) and T-wave inversion in V1-V4 (34%) were the main electrocardiographic abnormalities. Chest X-ray was normal in 30% of patients. Right ventricular pressure overload was detected in 58% of patients who had access to echocardiography. Computed tomography pulmonary angiography was performed in 65% of patients. All patients were treated with anticoagulants; no cases received thrombolytics. Patients who died (7%) were all in class III-V according to the Pulmonary Embolism Severity Index prognostic score. PE is common in Kinshasa, with characteristics similar to those reported in the literature.

Performance characteristics of mobile MOSFET dosimeter for kilovoltage X-rays used in image guided radiotherapy

PubMed Central

Kumar, A. Sathish; Singh, I. Rabi Raja; Sharma, S. D.; Ravindran, B. Paul

2015-01-01

The main objective of this study was to investigate the characteristics of metal oxide semiconductor field effect transistor (MOSFET) dosimeter for kilovoltage (kV) X-ray beams in order to perform the in vivo dosimetry during image guidance in radiotherapy. The performance characteristics of high sensitivity MOSFET dosimeters were investigated for 80, 90, 100, 110, 120, and 125 kV X-ray beams used for imaging in radiotherapy. This study was performed using Clinac 2100 C/D medical electron linear accelerator with on-board imaging and kV cone beam computed tomography system. The characteristics studied in this work include energy dependence, angular dependence, and linearity. The X-ray beam outputs were measured as per American Association of Physicists in Medicine (AAPM) TG 61 recommendations using PTW parallel plate (PP) ionization chamber, which was calibrated in terms of air kerma (Nk) by the National Standard Laboratory. The MOSFET dosimeters were calibrated against the PP ionization chamber for all the kV X-ray beams and the calibration coefficient was found to be 0.11 cGy/mV with a standard deviation of about ±1%. The response of MOSFET was found to be energy independent for the kV X-ray energies used in this study. The response of the MOSFET dosimeter was also found independent of angle of incidence for the gantry angles in the range of 0° to 360° in-air as well as at 3 cm depth in tissue equivalent phantom. PMID:26500397

Study of SF6 gas decomposition products based on spectroscopy technology

NASA Astrophysics Data System (ADS)

Cai, Ji-xing; Na, Yan-xiang; Ni, Wei-yuan; Li, Guo-wei; Feng, Ke-cheng; Song, Gui-cai

2011-08-01

With the rapid development of power industry, the number of SF6 electrical equipment are increasing, it has gradually replaced the traditional insulating oil material as insulation and arc media in the high-voltage electrical equipment. Pure SF6 gas has excellent insulating properties and arc characteristics; however, under the effect of the strong arc, SF6 gas will decompose and generate toxic substances, then corroding electrical equipment, thereby affecting the insulation and arc ability of electrical equipment. If excessive levels of impurities in the gas that will seriously affect the mechanical properties, breaking performance and electrical performance of electrical equipment, it will cause many serious consequences, even threaten the safe operation of the grid. This paper main analyzes the basic properties of SF6 gas and the basic situation of decomposition in the discharge conditions, in order to simulate the actual high-voltage electrical equipment, designed and produced a simulation device that can simulate the decomposition of SF6 gas under a high voltage discharge, and using fourier transform infrared spectroscopy to analyze the sample that produced by the simulation device. The result show that the main discharge decomposition product is SO2F2 (sulfuryl fluoride), the substance can react with water and generate corrosive H2SO4(sulfuric acid) and HF (hydrogen fluoride), also found that the increase in the number with the discharge, SO2F2concentration levels are on the rise. Therefore, the material can be used as one of the main characteristic gases to determine the SF6 electrical equipment failure, and to monitor their concentration levels.

Improving The Performance of Customer Loyalty of Online Ticketing in Indonesia's Showbiz Industry

NASA Astrophysics Data System (ADS)

Dachyar, M.; Athory, E. S.

2015-06-01

Currently the entertainment industry is adopting online ticketing for supporting business from main products to profitability improvement. E-loyalty needs to be examined because are deals with less loyal customer characteristic. The sample are 249 customers whom have purchased for tickets online at least once. Data was gathered by questionnaires and analyzed by Path Analysis and Importance - Performance Analysis. The findings of the research indicate that satisfaction has the strongest relationship to e-loyalty. This study provides four improvement alternatives as a form of new business development strategy for showbiz industry in Indonesia.

Sampling methods for microbiological analysis of red meat and poultry carcasses.

PubMed

Capita, Rosa; Prieto, Miguel; Alonso-Calleja, Carlos

2004-06-01

Microbiological analysis of carcasses at slaughterhouses is required in the European Union for evaluating the hygienic performance of carcass production processes as required for effective hazard analysis critical control point implementation. The European Union microbial performance standards refer exclusively to the excision method, even though swabbing using the wet/dry technique is also permitted when correlation between both destructive and nondestructive methods can be established. For practical and economic reasons, the swab technique is the most extensively used carcass surface-sampling method. The main characteristics, advantages, and limitations of the common excision and swabbing methods are described here.

Investigation of hollow cathode performance for 30-cm thrusters

NASA Technical Reports Server (NTRS)

Mirtich, M. J.

1973-01-01

A parametric investigation of 6.35 mm diameter mercury hollow cathodes was carried out in a bell jar. The parameters that were varied were the amount of initial emissive mix, the insert position, the emission current, the cathode temperature, the orifice diameter, and the mercury flow rate. Flow characteristic curves and performance as a function of time were obtained for the various cathodes of interest. Also presented are the results of a 3880 hr life test of a main cathode run at 15 amps emission current with no noticeable changes in keeper and collector voltages.

CMOS image sensors: State-of-the-art

NASA Astrophysics Data System (ADS)

Theuwissen, Albert J. P.

2008-09-01

This paper gives an overview of the state-of-the-art of CMOS image sensors. The main focus is put on the shrinkage of the pixels : what is the effect on the performance characteristics of the imagers and on the various physical parameters of the camera ? How is the CMOS pixel architecture optimized to cope with the negative performance effects of the ever-shrinking pixel size ? On the other hand, the smaller dimensions in CMOS technology allow further integration on column level and even on pixel level. This will make CMOS imagers even smarter that they are already.

Investigation of approximate models of experimental temperature characteristics of machines

NASA Astrophysics Data System (ADS)

Parfenov, I. V.; Polyakov, A. N.

2018-05-01

This work is devoted to the investigation of various approaches to the approximation of experimental data and the creation of simulation mathematical models of thermal processes in machines with the aim of finding ways to reduce the time of their field tests and reducing the temperature error of the treatments. The main methods of research which the authors used in this work are: the full-scale thermal testing of machines; realization of various approaches at approximation of experimental temperature characteristics of machine tools by polynomial models; analysis and evaluation of modelling results (model quality) of the temperature characteristics of machines and their derivatives up to the third order in time. As a result of the performed researches, rational methods, type, parameters and complexity of simulation mathematical models of thermal processes in machine tools are proposed.

An instrument for assessment of videotapes of general practitioners' performance.

PubMed Central

Cox, J; Mulholland, H

1993-01-01

OBJECTIVES--To identify those important characteristics of doctors' and patients' behaviour that distinguish between "good" and "bad" consultations when viewed on videotape; to use these characteristics to develop a reliable instrument for assessing general practitioners' performance in their own consultations. DESIGN--Questionnaires completed by patients, general practitioner trainers, and general practitioner trainees. Reliability of draft instrument tested by general practitioner trainers. SETTING--All vocational training schemes for general practice in the Northern region of England. SUBJECTS--First stage: 76 patients in seven groups, 108 general practice trainers in 12 groups, and 122 general practice trainees in 10 groups. Second stage: 85 general practice trainers in 12 groups. MAIN OUTCOME MEASURES--Trainers' ratings of importance; alpha coefficients of draft instrument by trainee, group, and consultation. RESULTS--6890 characteristics of good and bad consultations were consolidated into a draft assessment instrument consisting of 46 pairs of definitions separated by six point bipolar scales. Nine statement pairs given low importance ratings by trainers were eliminated, reducing the instrument to 37 statement pairs. To test reliability, general practitioner trainers used the instrument to assess three consultations. With the exception of one group of trainers, all alpha coefficients exceeded the acceptable level of 0.80. CONCLUSION--The instrument produced is reliable for assessing general practitioners' performance in their own consultations. PMID:8490501

A Comparative Study on Ni-Based Coatings Prepared by HVAF, HVOF, and APS Methods for Corrosion Protection Applications

NASA Astrophysics Data System (ADS)

Sadeghimeresht, E.; Markocsan, N.; Nylén, P.

2016-12-01

Selection of the thermal spray process is the most important step toward a proper coating solution for a given application as important coating characteristics such as adhesion and microstructure are highly dependent on it. In the present work, a process-microstructure-properties-performance correlation study was performed in order to figure out the main characteristics and corrosion performance of the coatings produced by different thermal spray techniques such as high-velocity air fuel (HVAF), high-velocity oxy fuel (HVOF), and atmospheric plasma spraying (APS). Previously optimized HVOF and APS process parameters were used to deposit Ni, NiCr, and NiAl coatings and compare with HVAF-sprayed coatings with randomly selected process parameters. As the HVAF process presented the best coating characteristics and corrosion behavior, few process parameters such as feed rate and standoff distance (SoD) were investigated to systematically optimize the HVAF coatings in terms of low porosity and high corrosion resistance. The Ni and NiAl coatings with lower porosity and better corrosion behavior were obtained at an average SoD of 300 mm and feed rate of 150 g/min. The NiCr coating sprayed at a SoD of 250 mm and feed rate of 75 g/min showed the highest corrosion resistance among all investigated samples.

Effect of hydrogen on ethanol-biodiesel blend on performance and emission characteristics of a direct injection diesel engine.

PubMed

Parthasarathy, M; Isaac JoshuaRamesh Lalvani, J; Dhinesh, B; Annamalai, K

2016-12-01

Environment issue is a principle driving force which has led to a considerable effort to develop and introduce alternative fuels for transportation. India has large potential for production of biofuels like biodiesel from vegetable seeds. Use of biodiesel namely, tamanu methyl ester (TME) in unmodified diesel engines leads to low thermal Efficiency and high smoke emission. To encounter this problem hydrogen was inducted by a port fueled injection system. Hydrogen is considered to be low polluting fuel and is the most promising among alternative fuel. Its clean burning characteristic and better performance attract more interest compared to other fuels. It was more active in reducing smoke emission in biodiesel. A main drawback with hydrogen fuel is the increased NO x emission. To reduce NO x emission, TME-ethanol blends were used in various proportions. After a keen study, it was observed that ethanol can be blended with biodiesel up to 30% in unmodified diesel engine. The present work deals with the experimental study of performance and emission characteristic of the DI diesel engine using hydrogen and TME-ethanol blends. Hydrogen and TME-ethanol blend was used to improve the brake thermal efficiency and reduction in CO, NO x and smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

Software and package applicating for network meta-analysis: A usage-based comparative study.

PubMed

Xu, Chang; Niu, Yuming; Wu, Junyi; Gu, Huiyun; Zhang, Chao

2017-12-21

To compare and analyze the characteristics and functions of software applications for network meta-analysis (NMA). PubMed, EMbase, The Cochrane Library, the official websites of Bayesian inference Using Gibbs Sampling (BUGS), Stata and R, and Google were searched to collect the software and packages for performing NMA; software and packages published up to March 2016 were included. After collecting the software, packages, and their user guides, we used the software and packages to calculate a typical example. All characteristics, functions, and computed results were compared and analyzed. Ten types of software were included, including programming and non-programming software. They were developed mainly based on Bayesian or frequentist theory. Most types of software have the characteristics of easy operation, easy mastery, exact calculation, or excellent graphing. However, there was no single software that performed accurate calculations with superior graphing; this could only be achieved through the combination of two or more types of software. This study suggests that the user should choose the appropriate software according to personal programming basis, operational habits, and financial ability. Then, the choice of the combination of BUGS and R (or Stata) software to perform the NMA is considered. © 2017 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

From SED HI concept to Pleiades FM detection unit measurements

NASA Astrophysics Data System (ADS)

Renard, Christophe; Dantes, Didier; Neveu, Claude; Lamard, Jean-Luc; Oudinot, Matthieu; Materne, Alex

2017-11-01

The first flight model PLEIADES high resolution instrument under Thales Alenia Space development, on behalf of CNES, is currently in integration and test phases. Based on the SED HI detection unit concept, PLEIADES detection unit has been fully qualified before the integration at telescope level. The main radiometric performances have been measured on engineering and first flight models. This paper presents the results of performances obtained on the both models. After a recall of the SED HI concept, the design and performances of the main elements (charge coupled detectors, focal plane and video processing unit), detection unit radiometric performances are presented and compared to the instrument specifications for the panchromatic and multispectral bands. The performances treated are the following: - video signal characteristics, - dark signal level and dark signal non uniformity, - photo-response non uniformity, - non linearity and differential non linearity, - temporal and spatial noises regarding system definitions PLEIADES detection unit allows tuning of different functions: reference and sampling time positioning, anti-blooming level, gain value, TDI line number. These parameters are presented with their associated criteria of optimisation to achieve system radiometric performances and their sensitivities on radiometric performances. All the results of the measurements performed by Thales Alenia Space on the PLEIADES detection units demonstrate the high potential of the SED HI concept for Earth high resolution observation system allowing optimised performances at instrument and satellite levels.

Sensitivity analysis with the regional climate model COSMO-CLM over the CORDEX-MENA domain

NASA Astrophysics Data System (ADS)

Bucchignani, E.; Cattaneo, L.; Panitz, H.-J.; Mercogliano, P.

2016-02-01

The results of a sensitivity work based on ERA-Interim driven COSMO-CLM simulations over the Middle East-North Africa (CORDEX-MENA) domain are presented. All simulations were performed at 0.44° spatial resolution. The purpose of this study was to ascertain model performances with respect to changes in physical and tuning parameters which are mainly related to surface, convection, radiation and cloud parameterizations. Evaluation was performed for the whole CORDEX-MENA region and six sub-regions, comparing a set of 26 COSMO-CLM runs against a combination of available ground observations, satellite products and reanalysis data to assess temperature, precipitation, cloud cover and mean sea level pressure. The model proved to be very sensitive to changes in physical parameters. The optimized configuration allows COSMO-CLM to improve the simulated main climate features of this area. Its main characteristics consist in the new parameterization of albedo, based on Moderate Resolution Imaging Spectroradiometer data, and the new parameterization of aerosol, based on NASA-GISS AOD distributions. When applying this configuration, Mean Absolute Error values for the considered variables are as follows: about 1.2 °C for temperature, about 15 mm/month for precipitation, about 9 % for total cloud cover, and about 0.6 hPa for mean sea level pressure.

Modification of ferrierite through post-synthesis treatments. Acidic and catalytic properties

NASA Astrophysics Data System (ADS)

Brylewska, Kamila; Tarach, Karolina A.; Mozgawa, Włodzimierz; Olejniczak, Zbigniew; Filek, Urszula; Góra-Marek, Kinga

2016-12-01

The main emphasis of this work was placed on a detailed characterization of structural, textural and acidic properties of FER zeolites with different Si/Al ratios in terms of their activity in ethanol dehydration reaction. Subsequent dealumination and desilication procedures were found to be an efficient methods of a secondary system of mesopore generation in the ferrierite crystals with preservation of their microporous characteristics. Through ethanol dehydration both the acidic and the textural features have a significant influence on catalytic performance of hierarchical ferrierites. It was shown that higher catalytic activity and selectivity to ethylene is ensured by zeolites with highly preserved microporous characteristic, i.e. well-developed micropore area and intrinsic acidity.

Investigation of an anomalous hump phenomenon in via-type amorphous In-Ga-Zn-O thin-film transistors under positive bias temperature stress

NASA Astrophysics Data System (ADS)

Yang, Jianwen; Liao, Po-Yung; Chang, Ting-Chang; Chen, Bo-Wei; Huang, Hui-Chun; Su, Wan-Ching; Chiang, Hsiao-Cheng; Zhang, Qun

2017-04-01

Amorphous InGaZnO thin film transistors (a-IGZO TFTs) with an etching-stop layer (ESL) exhibit an anomalous negative shift of threshold voltage (Vth) under positive bias temperature stress. TFTs with wider and shorter channels show a clear hump phenomenon, resulting from the existence of both main channels and parasitic channels. The electrons trapped in the gate insulator are responsible for the positive shift in the main channel characteristics. The electrons trapped near the IGZO edges and the holes injected into the ESL layer above InGaZnO (IGZO) jointly determine the shift of the parasitic TFT performance.

Customer-experienced rapid prototyping

NASA Astrophysics Data System (ADS)

Zhang, Lijuan; Zhang, Fu; Li, Anbo

2008-12-01

In order to describe accurately and comprehend quickly the perfect GIS requirements, this article will integrate the ideas of QFD (Quality Function Deployment) and UML (Unified Modeling Language), and analyze the deficiency of prototype development model, and will propose the idea of the Customer-Experienced Rapid Prototyping (CE-RP) and describe in detail the process and framework of the CE-RP, from the angle of the characteristics of Modern-GIS. The CE-RP is mainly composed of Customer Tool-Sets (CTS), Developer Tool-Sets (DTS) and Barrier-Free Semantic Interpreter (BF-SI) and performed by two roles of customer and developer. The main purpose of the CE-RP is to produce the unified and authorized requirements data models between customer and software developer.

Predicting performance: relative importance of students' background and past performance.

PubMed

Stegers-Jager, Karen M; Themmen, Axel P N; Cohen-Schotanus, Janke; Steyerberg, Ewout W

2015-09-01

Despite evidence for the predictive value of both pre-admission characteristics and past performance at medical school, their relative contribution to predicting medical school performance has not been thoroughly investigated. This study was designed to determine the relative importance of pre-admission characteristics and past performance in medical school in predicting student performance in pre-clinical and clinical training. This longitudinal prospective study followed six cohorts of students admitted to a Dutch, 6-year, undergraduate medical course during 2002-2007 (n = 2357). Four prediction models were developed using multivariate logistic regression analysis. Main outcome measures were 'Year 1 course completion within 1 year' (models 1a, 1b), 'Pre-clinical course completion within 4 years' (model 2) and 'Achievement of at least three of five clerkship grades of ≥ 8.0' (model 3). Pre-admission characteristics (models 1a, 1b, 2, 3) and past performance at medical school (models 1b, 2, 3) were included as predictor variables. In model 1a - including pre-admission characteristics only - the strongest predictor for Year 1 course completion was pre-university grade point average (GPA). Success factors were 'selected by admission testing' and 'age > 21 years'; risk factors were 'Surinamese/Antillean background', 'foreign pre-university degree', 'doctor parent' and male gender. In model 1b, number of attempts and GPA at 4 months were the strongest predictors for Year 1 course completion, and male gender remained a risk factor. Year 1 GPA was the strongest predictor for pre-clinical course completion, whereas being male or aged 19-21 years were risk factors. Pre-clinical course GPA positively predicted clinical performance, whereas being non-Dutch or a first-generation university student were important risk factors for lower clinical grades. Nagelkerke's R(2) ranged from 0.16 to 0.62. This study not only confirms the importance of past performance as a predictor of future performance in pre-clinical training, but also reveals the importance of a student's background as a predictor in clinical training. These findings have important practical implications for selection and support during medical school. © 2015 John Wiley & Sons Ltd.

Review on analog/radio frequency performance of advanced silicon MOSFETs

NASA Astrophysics Data System (ADS)

Passi, Vikram; Raskin, Jean-Pierre

2017-12-01

Aggressive gate-length downscaling of the metal-oxide-semiconductor field-effect transistor (MOSFET) has been the main stimulus for the growth of the integrated circuit industry. This downscaling, which has proved beneficial to digital circuits, is primarily the result of the need for improved circuit performance and cost reduction and has resulted in tremendous reduction of the carrier transit time across the channel, thereby resulting in very high cut-off frequencies. It is only in recent decades that complementary metal-oxide-semiconductor (CMOS) field-effect transistor (FET) has been considered as the radio frequency (RF) technology of choice. In this review, the status of the digital, analog and RF figures of merit (FoM) of silicon-based FETs is presented. State-of-the-art devices with very good performance showing low values of drain-induced barrier lowering, sub-threshold swing, high values of gate transconductance, Early voltage, cut-off frequencies, and low minimum noise figure, and good low-frequency noise characteristic values are reported. The dependence of these FoM on the device gate length is also shown, helping the readers to understand the trends and challenges faced by shorter CMOS nodes. Device performance boosters including silicon-on-insulator substrates, multiple-gate architectures, strain engineering, ultra-thin body and buried-oxide and also III-V and 2D materials are discussed, highlighting the transistor characteristics that are influenced by these boosters. A brief comparison of the two main contenders in continuing Moore’s law, ultra-thin body buried-oxide and fin field-effect transistors are also presented. The authors would like to mention that despite extensive research carried out in the semiconductor industry, silicon-based MOSFET will continue to be the driving force in the foreseeable future.

Effect of a gymnastics program on sleep characteristics in pregnant women.

PubMed

Kocsis, Ildikó; Szilágyi, Tibor; Turos, János; Bakó, Aliz; Frigy, Attila

2017-04-01

The quality and quantity of sleep represent important health issues in pregnant women. Sleep disturbances could be associated, beyond alteration of quality of life, with poor pregnancy outcome. Our aim was to investigate the effect of a regular, specific, medium-term physical training program on sleep characteristics in healthy pregnant women. A total of 132 healthy pregnant women, with gestational age between 18 weeks and 22 weeks, were enrolled in a prospective study. They were allocated into two groups; the first group involved 79 women (average age, 29.4 years) who performed a specific gymnastics program of 10 weeks, and the second group involved 53 pregnant women (average age, 27.9 years) who did not perform gymnastics. All participants completed a comprehensive questionnaire at baseline and after 10 weeks concerning general data, sleep characteristics, and psycho-emotional status. The changes arising within a diverse set of characteristics were followed and compared for the two groups using parametric and nonparametric statistics. In the control group, we observed significant worsening of 12 out of the 14 studied parameters during the 10-week period. In comparison with the women who did not perform gymnastics, women who performed specific gymnastics showed the following characteristics: (1) significantly less deterioration of psycho-emotional status (stress and anxiety levels); (2) the same general pattern of decrease in sleep quality, which is related to the progression of pregnancy; and (3) a significant attenuation of the worsening of several sleep characteristics, such as restless sleep, snoring, diurnal tiredness, and excessive daytime sleepiness. Nocturnal and diurnal sleep quantity increased significantly in both groups. The 10-week training program designed for pregnant women has an overall beneficial effect on sleep characteristics, not by improving them but by attenuating their general deterioration related to the progression of pregnancy. Our data strengthen the general recommendation regarding participation of pregnant women in specific exercise programs, mainly for maintaining their psycho-emotional and general well-being. Copyright © 2017. Published by Elsevier B.V.

Physician Perceptions of Performance Feedback in a Quality Improvement Activity.

PubMed

Eden, Aimee R; Hansen, Elizabeth; Hagen, Michael D; Peterson, Lars E

Physician performance and peer comparison feedback can affect physician care quality and patient outcomes. This study aimed to understand family physician perspectives of the value of performance feedback in quality improvement (QI) activities. This study analyzed American Board of Family Medicine open-ended survey data collected between 2004 and 2014 from physicians who completed a QI module that provided pre- and post-QI project individual performance data and peer comparisons. Physicians made 3480 comments in response to a question about this performance feedback, which were generally positive in nature (86%). Main themes that emerged were importance of accurate feedback data, enhanced detail in the content of feedback, and ability to customize peer comparison groups to compare performance to peers with similar patient populations or practice characteristics. Meaningful and tailored performance feedback may be an important tool for physicians to improve their care quality and should be considered an integral part of QI project design.

Subsequent bone and metabolic responses of broilers to high-non-phytate phosphorus diets in the starter period.

PubMed

Baradaran, N; Shahir, M H; Asadi Kermani, Z

2017-08-01

1. An experiment was performed to elucidate the subsequent effects of high-non-phytate phosphorus (NPP) diets on growth performance, blood metabolites, bone characteristics and P retention of broilers fed on low-NPP grower diets. The 42-d study was designed as a 2 × 2 × 2 + 1 factorial, which included two starter NPP concentrations (4.5 and 5.5 g/kg; d 0-21), two grower NPP concentrations (1.5 and 2.3 g/kg; d 22-42), with or without phytase (1000 FTU/kg), with a reference diet containing an adequate NPP concentration over the course of the trial. 2. In the starter period, growth performance and P retention were not affected by experimental diets. The high-NPP diet increased plasma P concentration, increased tibia ash and tibia P contents and decreased plasma alkaline phosphatase (ALP) activity at d 21. 3. No significant interaction was observed between NPP concentrations in the starter and grower periods and phytase. The main effect data indicated that the increase in NPP concentration in the starter diets had no effects on growth performance in the grower period and overall. The high-NPP diet in the early stage of growth reduced plasma P concentration, plasma ALP activity and tibia ash content at d 42. The main effect data also showed that exogenous phytase increased body weight gain in the grower period and overall. 4. It can be concluded that feeding increased NPP diets have no effects on growth performance in the starter period. This feeding strategy results in negative effects on plasma P concentration and bone ash content at d 42. Also, exogenous phytase is effective in improving growth performance, bone characteristics and apparent P retention of growing broilers fed diets that are inadequate in phosphorus.

Mesenchymal stem cells transplantation in hematological patients with acute graft-versus-host disease: characteristics and risk factors for infectious complications.

PubMed

Stoma, Igor; Karpov, Igor; Krivenko, Svetlana; Iskrov, Igor; Milanovich, Natalia; Koritko, Alla; Uss, Anatoly

2018-05-01

The role of MSCs in infection prevention and treatment is still discussed in transplant and hematological patients. The spectrum and risk factors for infections after MSCs transplantation in patients with acute GVHD have not been studied before. To determine the risk factors and spectrum of infectious complications in patients received mesenchymal stem cell transplantation as a treatment for acute GVHD. A prospective observational study was performed to evaluate the risk factors and characteristics of infectious complications after MSCs transplantation in adult patients having acute GVHD. Thirty-four episodes of MSCs transplantation in patients with acute GVHD after allogeneic HSCT were enrolled in the study. MSCs were given at a median dose of 1.32 (interquartile range 0.87-2.16) mln cells/kg per infusion at 91 days (interquartile range 31-131 days) after HSCT. Data relating to age, gender, date, and type of transplantation, characteristics of MSCs, infectious agents, and antimicrobial therapy and prevention regimens were prospectively collected in all of the enrolled patients. The episode of proven infectious complication was set as a primary outcome. There were totally 68 patients with acute GVHD in the study; among them there were 34 cases of MSCs transplantation performed. Among the registered infectious episodes were viral infections (CMV-associated disease, EBV-associated disease), invasive pulmonary aspergillosis, bacterial bloodstream infections, and pneumonia. MSCs transplantation has shown no statistically significant association with risk of infectious complications in patients with acute GVHD in a performed multivariate analysis. Among the most frequent infections in acute GVHD, we have described CMV, invasive aspergillosis, and bacterial infections (bloodstream infections or pneumonia). Among risk factors for infectious complications in patients with acute GVHD with/without MSCs transplantation are progression of main disease and neutropenia below 500 cells/mm 3 (for aspergillosis) and unrelated HSCT in the past history and progression of main disease (for bacterial bloodstream infections and pneumonia).

Dynamic characterization of fractured carbonates at the Hontomín CO2 storage site

NASA Astrophysics Data System (ADS)

Le Gallo, yann; de Dios, José Carlos; Salvador, Ignacio; Acosta Carballo, Taimara

2017-04-01

The geological storage of CO2 is investigated at the Technology Development Plant (TDP) at Hontomín (Burgos, Spain) into a deep saline aquifer, formed by fractured carbonates with poor matrix porosity. During the hydraulic characterization tests, 2,300 tons of liquid CO2 and 14,000 m3 synthetic brine were co-injected on site in various sequences to determine the pressure and temperature responses of the facture network. The results of the pressure tests were analyzed using an analytical approach to determine the overall petrophysical characteristics of the storage formation. Later on, these characteristics were implemented in a 3-D numerical model. The model is a compositional dual medium (fracture + matrix) which accounts for temperature effects, as CO2 is liquid at the well bottom-hole, and multiphase flow hysteresis as alternating water and CO2 injection tests were performed. The pressure and temperature responses of the storage formation were history-matched mainly through the petrophysical and geometrical characteristics of the facture network. This dynamic characterization of the fracture network controls the CO2 migration while the matrix does not appear to significantly contribute to the storage capacity. Consequently, the hydrodynamic behavior of the aquifer is one of the main challenge of the modeling workflow.

Performances of the Poseidon-2 altimeter instrument onboard Jason-1

NASA Astrophysics Data System (ADS)

Carayon, G.; Steunou, N.; Courrière, J. L.; Thibaut, P.; Zanife, O. Z.; Vincent, P.

Since July 2003, Jason-1 is providing sea-level and sea-state altimetric data in a routine way, including near-real time and fully validated off-line geophysical products. The main mission of Jason-1 is to maintain the high accuracy altimeter service, provided by TOPEX/POSEIDON (T/P) since 1992, insuring the continuity in observing and monitoring the Ocean Dynamics (intra-seasonal to inter-annual changes, mean sea level, tides...). Successfully launched by a Boeing Delta 2 rocket from the Vandenberg site (CA, USA) on December 7, 2001, Jason-1 has been designed to follow on from T/P: its instruments and data processing systems have drawn extensively on the lessons learned from its predecessor. The Jason-1 altimetric payload is composed with four main elements: satellite tracking systems (a laser retro-reflector array, DORIS, and a Turbo-Rogue GPS receiver), a three-frequency water vapor radiometer and a dual-frequency altimeter that is named POSEIDON-2. The POSEIDON-2 altimeter inherits many characteristics from the experimental POSEIDON-1 that has been successfully operating since mid-1992 onboard T/P. This new generation altimeter radar is provided in full redundancy: It comprises high reliability components in order to achieve the 5 years expected lifetime. Ionospheric delay is removed through the introduction of an additional C-band measurement channel interleaved with Ku-band measurements. Each altimeter instrument exhibits a mass of 25 kg and a power consumption of 70 W. After summarizing the POSEIDON-2 design : technical characteristics, main operating modes, onboard algorithms, in flight performances will be presented more extensively: results from instrument internal calibrations, estimations of noise on the measured parameters. As a conclusion, more global results dealing with the calibration and validation of the Jason-1 altimetric measurements will be presented, and performance comparisons with T/P will be illustrated.

Evaluation of SSME test data reduction methods

NASA Technical Reports Server (NTRS)

Santi, L. Michael

1994-01-01

Accurate prediction of hardware and flow characteristics within the Space Shuttle Main Engine (SSME) during transient and main-stage operation requires a significant integration of ground test data, flight experience, and computational models. The process of integrating SSME test measurements with physical model predictions is commonly referred to as data reduction. Uncertainties within both test measurements and simplified models of the SSME flow environment compound the data integration problem. The first objective of this effort was to establish an acceptability criterion for data reduction solutions. The second objective of this effort was to investigate the data reduction potential of the ROCETS (Rocket Engine Transient Simulation) simulation platform. A simplified ROCETS model of the SSME was obtained from the MSFC Performance Analysis Branch . This model was examined and tested for physical consistency. Two modules were constructed and added to the ROCETS library to independently check the mass and energy balances of selected engine subsystems including the low pressure fuel turbopump, the high pressure fuel turbopump, the low pressure oxidizer turbopump, the high pressure oxidizer turbopump, the fuel preburner, the oxidizer preburner, the main combustion chamber coolant circuit, and the nozzle coolant circuit. A sensitivity study was then conducted to determine the individual influences of forty-two hardware characteristics on fourteen high pressure region prediction variables as returned by the SSME ROCETS model.

The Case for Distributed Engine Control in Turbo-Shaft Engine Systems

NASA Technical Reports Server (NTRS)

Culley, Dennis E.; Paluszewski, Paul J.; Storey, William; Smith, Bert J.

2009-01-01

The turbo-shaft engine is an important propulsion system used to power vehicles on land, sea, and in the air. As the power plant for many high performance helicopters, the characteristics of the engine and control are critical to proper vehicle operation as well as being the main determinant to overall vehicle performance. When applied to vertical flight, important distinctions exist in the turbo-shaft engine control system due to the high degree of dynamic coupling between the engine and airframe and the affect on vehicle handling characteristics. In this study, the impact of engine control system architecture is explored relative to engine performance, weight, reliability, safety, and overall cost. Comparison of the impact of architecture on these metrics is investigated as the control system is modified from a legacy centralized structure to a more distributed configuration. A composite strawman system which is typical of turbo-shaft engines in the 1000 to 2000 hp class is described and used for comparison. The overall benefits of these changes to control system architecture are assessed. The availability of supporting technologies to achieve this evolution is also discussed.

Liquid Oxygen/Liquid Methane Integrated Propulsion System Test Bed

NASA Technical Reports Server (NTRS)

Flynn, Howard; Lusby, Brian; Villemarette, Mark

2011-01-01

In support of NASA?s Propulsion and Cryogenic Advanced Development (PCAD) project, a liquid oxygen (LO2)/liquid methane (LCH4) Integrated Propulsion System Test Bed (IPSTB) was designed and advanced to the Critical Design Review (CDR) stage at the Johnson Space Center. The IPSTB?s primary objectives are to study LO2/LCH4 propulsion system steady state and transient performance, operational characteristics and to validate fluid and thermal models of a LO2/LCH4 propulsion system for use in future flight design work. Two phase thermal and dynamic fluid flow models of the IPSTB were built to predict the system performance characteristics under a variety of operating modes and to aid in the overall system design work. While at ambient temperature and simulated altitude conditions at the White Sands Test Facility, the IPSTB and its approximately 600 channels of system instrumentation would be operated to perform a variety of integrated main engine and reaction control engine hot fire tests. The pressure, temperature, and flow rate data collected during this testing would then be used to validate the analytical models of the IPSTB?s thermal and dynamic fluid flow performance. An overview of the IPSTB design and analytical model development will be presented.

Identification of Natural Oscillation Modes for Purposes of Seismic Assessment and Monitoring of HPP Dams

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

Kuz’menko, A. P., E-mail: apkuzm@gmail.com; Saburov, S. V., E-mail: saburov58@yandex.ru

2016-07-15

The paper puts forward a method for processing data from detailed seismic assessments of HPP dams (dynamic tests). A detailed assessment (hundreds of observation points in dam galleries) is performed with consideration of operating dam equipment and the microseismic noise. It is shown that dynamic oscillation characteristics (natural oscillation frequencies and modes in the main dam axes, the velocities of propagation of elastic waves with given polarization, and so on.) can be determined with sufficient accuracy by using complex transfer functions and pulse characteristics. Monitoring data is processed using data from a detailed assessment, taking account of identified natural oscillationmore » modes and determined ranges of natural frequencies. The spectra of characteristic frequencies thus obtained are used to choose substitution models and estimate the elastic characteristics of the “dam – rock bed” construction system, viz., the modulus of elasticity (the Young modulus), the Poisson ratio, the dam section stiffness with respect to shear, tension and compression and the elastic characteristics of the rock foundation.« less

Performance Evaluation and Parameter Identification on DROID III

NASA Technical Reports Server (NTRS)

Plumb, Julianna J.

2011-01-01

The DROID III project consisted of two main parts. The former, performance evaluation, focused on the performance characteristics of the aircraft such as lift to drag ratio, thrust required for level flight, and rate of climb. The latter, parameter identification, focused on finding the aerodynamic coefficients for the aircraft using a system that creates a mathematical model to match the flight data of doublet maneuvers and the aircraft s response. Both portions of the project called for flight testing and that data is now available on account of this project. The conclusion of the project is that the performance evaluation data is well-within desired standards but could be improved with a thrust model, and that parameter identification is still in need of more data processing but seems to produce reasonable results thus far.

Metal coordination polymer derived mesoporous Co3O4 nanorods with uniform TiO2 coating as advanced anodes for lithium ion batteries.

PubMed

Geng, Hongbo; Ang, Huixiang; Ding, Xianguang; Tan, Huiteng; Guo, Guile; Qu, Genlong; Yang, Yonggang; Zheng, Junwei; Yan, Qingyu; Gu, Hongwei

2016-02-07

In this work, a one-dimensional Co3O4@TiO2 core-shell electrode material with superior electrochemical performance is fabricated by a convenient and controllable route. The approach involves two main steps: the homogeneous deposition of polydopamine and TiO2 layers in sequence on the cobalt coordination polymer and the thermal decomposition of the polymer matrix. The as-prepared electrode material can achieve excellent electrochemical properties and stability as an anode material for lithium ion batteries, such as a high specific capacity of 1279 mA h g(-1), good cycling stability (around 803 mA h g(-1) at a current density of 200 mA g(-1) after 100 cycles), and stable rate performance (around 520 mA h g(-1) at a current density of 1000 mA g(-1)). This dramatic electrochemical performance is mainly attributed to the excellent structural characteristics, which could improve the electrical conductivity and lithium ion mobility, as well as electrolyte permeability and architectural stability during cycling.

An EGR performance evaluation and decision-making approach based on grey theory and grey entropy analysis

PubMed Central

2018-01-01

Exhaust gas recirculation (EGR) is one of the main methods of reducing NOX emissions and has been widely used in marine diesel engines. This paper proposes an optimized comprehensive assessment method based on multi-objective grey situation decision theory, grey relation theory and grey entropy analysis to evaluate the performance and optimize rate determination of EGR, which currently lack clear theoretical guidance. First, multi-objective grey situation decision theory is used to establish the initial decision-making model according to the main EGR parameters. The optimal compromise between diesel engine combustion and emission performance is transformed into a decision-making target weight problem. After establishing the initial model and considering the characteristics of EGR under different conditions, an optimized target weight algorithm based on grey relation theory and grey entropy analysis is applied to generate the comprehensive evaluation and decision-making model. Finally, the proposed method is successfully applied to a TBD234V12 turbocharged diesel engine, and the results clearly illustrate the feasibility of the proposed method for providing theoretical support and a reference for further EGR optimization. PMID:29377956

NADIR: A Flexible Archiving System Current Development

NASA Astrophysics Data System (ADS)

Knapic, C.; De Marco, M.; Smareglia, R.; Molinaro, M.

2014-05-01

The New Archiving Distributed InfrastructuRe (NADIR) is under development at the Italian center for Astronomical Archives (IA2) to increase the performances of the current archival software tools at the data center. Traditional softwares usually offer simple and robust solutions to perform data archive and distribution but are awkward to adapt and reuse in projects that have different purposes. Data evolution in terms of data model, format, publication policy, version, and meta-data content are the main threats to re-usage. NADIR, using stable and mature framework features, answers those very challenging issues. Its main characteristics are a configuration database, a multi threading and multi language environment (C++, Java, Python), special features to guarantee high scalability, modularity, robustness, error tracking, and tools to monitor with confidence the status of each project at each archiving site. In this contribution, the development of the core components is presented, commenting also on some performance and innovative features (multi-cast and publisher-subscriber paradigms). NADIR is planned to be developed as simply as possible with default configurations for every project, first of all for LBT and other IA2 projects.

Definition of realistic disturbances as a crucial step during the assessment of resilience of natural wastewater treatment systems.

PubMed

Cuppens, A; Smets, I; Wyseure, G

2012-01-01

Natural wastewater treatment systems (WWTSs) for urban areas in developing countries are subjected to large fluctuations in their inflow. This situation can result in a decreased treatment performance. The main aims of this paper are to introduce resilience as a performance indicator for natural WWTSs and to propose a methodology for the identification and generation of realistic disturbances of WWTSs. Firstly, a definition of resilience is formulated for natural WWTSs together with a short discussion of its most relevant properties. An important aspect during the evaluation process of resilience is the selection of appropriate disturbances. Disturbances of the WWTS are caused by fluctuations in water quantity and quality characteristics of the inflow. An approach to defining appropriate disturbances is presented by means of water quantity and quality data collected for the urban wastewater system of Coronel Oviedo (Paraguay). The main problem under consideration is the potential negative impact of stormwater inflow and infiltration in the sanitary sewer system on the treatment performance of anaerobic waste stabilisation ponds.

An EGR performance evaluation and decision-making approach based on grey theory and grey entropy analysis.

PubMed

Zu, Xianghuan; Yang, Chuanlei; Wang, Hechun; Wang, Yinyan

2018-01-01

Exhaust gas recirculation (EGR) is one of the main methods of reducing NOX emissions and has been widely used in marine diesel engines. This paper proposes an optimized comprehensive assessment method based on multi-objective grey situation decision theory, grey relation theory and grey entropy analysis to evaluate the performance and optimize rate determination of EGR, which currently lack clear theoretical guidance. First, multi-objective grey situation decision theory is used to establish the initial decision-making model according to the main EGR parameters. The optimal compromise between diesel engine combustion and emission performance is transformed into a decision-making target weight problem. After establishing the initial model and considering the characteristics of EGR under different conditions, an optimized target weight algorithm based on grey relation theory and grey entropy analysis is applied to generate the comprehensive evaluation and decision-making model. Finally, the proposed method is successfully applied to a TBD234V12 turbocharged diesel engine, and the results clearly illustrate the feasibility of the proposed method for providing theoretical support and a reference for further EGR optimization.

Spanish Heart Transplantation Registry. 27th Official Report of the Spanish Society of Cardiology Working Group on Heart Failure and Heart Transplantation (1984-2015).

PubMed

González-Vílchez, Francisco; Segovia Cubero, Javier; Almenar, Luis; Crespo-Leiro, María G; Arizón, José M; Sousa, Iago; Delgado, Juan; Roig, Eulalia; Sobrino, José Manuel; González-Costello, José

2016-11-01

The present article reports the characteristics and results of heart transplants in Spain since this therapeutic modality was first used in May 1984. We describe the main features of recipients, donors, surgical procedures, and results of all heart transplants performed in Spain until December 31, 2015. A total of 299 cardiac transplants were performed in 2015, with the whole series comprising 7588 procedures. The main transplant features in 2015 were similar to those observed in recent years. A remarkably high percentage of transplants were performed under emergency conditions and there was widespread use of circulatory assist devices, particularly continuous-flow left ventricular assist devices prior to transplant (16% of all transplants). Survival has significantly improved in the last decade compared with previous time periods. During the last few years, between 250 and 300 heart transplants have consistently been performed each year in Spain. Despite a more complex clinical context, survival has increased in recent years. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Effect of suction on the mechanical characteristics of uniformly compacted rammed earth

NASA Astrophysics Data System (ADS)

El Hajjar, A.; Chauhan, P.; Prime, N.; Plé, O.

2018-04-01

Rammed earth, in the current environmental situation, is an alternative construction technique which can help in reducing energy and raw material consumption owing to its “sustainable” characteristics. To fully understand its behavior and properties, recent scientific investigations consider it as a compacted unsaturated material with suction as its one of the main sources of strength. Eathern constructions face, over their lifetime, variations in the suction state which have a significant impact on their mechanical characteristics. In the present contribution, unconfined compression tests are performed, with and without unload-reload cycles, on homogeneously compacted samples subjected to various suction conditions. This study shows that both the unconfined compressive strength and Young modulus reduce with the reduction of suction states. Suction also seems to influence the amount of plastic strains and damage phenomenon. Indeed, the soils analyzed are slightly active and shows both plasticity behavior and damage phenomenon.

Flame Characteristics and Fuel Entrainment Inside a Cavity Flame Holder in a Scramjet Combustor (Postprint)

DTIC Science & Technology

2007-07-01

RBL was observed to be higher than RIL, due to the presence of hot combustion products and the effect of cavity wall temperature. Table 1...Vol. 17, No. 4, 2001, pp. 869-877. 3. Yu, K., Wilson K., and Schadow, K., “ Effect of Flame-Holding Cavities on Supersonic- Combustion Performance... combustion products and is relatively rich with main fuel only. Consequently, additional fuel injection into the cavity increases the probability of

Electromagnetic characteristics of systems of prolate and oblate ellipsoids

NASA Astrophysics Data System (ADS)

Karimi, Pouyan; Amiri-Hezaveh, Amirhossein; Ostoja-Starzewski, Martin; Jin, Jian-Ming

2017-11-01

The present study suggests a novel model for simulating electromagnetic characteristics of spheroidal nanofillers. The electromagnetic interference shielding efficiency of prolate and oblate ellipsoids in the X-band frequency range is studied. Different multilayered nanocomposite configurations incorporating carbon nanotubes, graphene nanoplatelets, and carbon blacks are fabricated and tested. The best performance for a specific thickness is observed for the multilayered composite with a gradual increase in the thickness and electrical conductivity of layers. The simulation results based on the proposed model are shown to be in good agreement with the experimental data. The effect of filler alignment on shielding efficiency is also studied by using the nematic order parameter. The ability of a nanocomposite to shield the incident power is found to decrease by increasing alignment especially for high volume fractions of prolate fillers. The interaction of the electromagnetic wave and the fillers is mainly affected by the polarization of the electric field; when the electric field is perpendicular to the equatorial axis of a spheroid, the interaction is significantly reduced and results in a lower shielding efficiency. Apart from the filler alignment, size polydispersity is found to have a significant effect on reflected and transmitted powers. It is demonstrated that the nanofillers with a higher aspect ratio mainly contribute to the shielding performance. The results are of interest in both shielding structures and microwave absorbing materials.

Preparation of Al/Fe-Pillared Clays: Effect of the Starting Mineral

PubMed Central

Muñoz, Helir-Joseph; Blanco, Carolina; Galeano, Luis-Alejandro

2017-01-01

Four natural clays were modified with mixed polyoxocations of Al/Fe for evaluating the effect of the physicochemical properties of the starting materials (chemical composition, abundance of expandable clay phases, cationic exchange capacity and textural properties) on final physicochemical and catalytic properties of Al/Fe-PILCs. The aluminosilicate denoted C2 exhibited the highest potential as starting material in the preparation of Al/Fe-PILC catalysts, mainly due to its starting cationic exchange capacity (192 meq/100 g) and the dioctahedral nature of the smectite phase. These characteristics favored the intercalation of the mixed (Al13−x/Fex)7+ Keggin-type polyoxocations, stabilizing a basal spacing of 17.4 Å and high increase of the BET surface (194 m2/g), mainly represented in microporous content. According to H2-TPR analyses, catalytic performance of the incorporated Fe in the Catalytic Wet Peroxide Oxidation (CWPO) reaction strongly depends on the level of location in mixed Al/Fe pillars. Altogether, such physicochemical characteristics promoted high performance in CWPO catalytic degradation of methyl orange in aqueous medium at very mild reaction temperatures (25.0 ± 1.0 °C) and pressure (76 kPa), achieving TOC removal of 52% and 70% of azo-dye decolourization in only 75 min of reaction under very low concentration of clay catalyst (0.05 g/L). PMID:29182560

Revealing the characteristics of a novel bioflocculant and its flocculation performance in Microcystis aeruginosa removal

NASA Astrophysics Data System (ADS)

Sun, Pengfei; Hui, Cai; Bai, Naling; Yang, Shengmao; Wan, Li; Zhang, Qichun; Zhao, Yuhua

2015-12-01

In the present work, a novel bioflocculant, EPS-1, was prepared and used to flocculate the kaolin suspension and Microcystis aeruginosa. We focused on the characteristics and flocculation performance of EPS-1, especially with regard to its protein components. An important attribute of EPS-1 was its protein content, with 18 protein types identified that occupied a total content of 31.70% in the EPS-1. Moreover, the flocculating activity of these protein components was estimated to be no less than 33.93%. Additionally, polysaccharides that occupied 57.12% of the total EPS-1 content consisted of four monosaccharides: maltose, D-xylose, mannose, and D-fructose. In addition, carbonyl, amino, and hydroxyl groups were identified as the main functional groups. Three main elements, namely C1s, N1s, and O1s, were present in EPS-1 with relative atomic percentages of 62.63%, 24.91%, and 10.5%, respectively. Zeta potential analysis indicated that charge neutralization contributed to kaolin flocculation, but was not involved in M. aeruginosa flocculation. The flocculation conditions of EPS-1 were optimized, and the maximum flocculating efficiencies were 93.34% within 2 min for kaolin suspension and 87.98% within 10 min for M. aeruginosa. These results suggest that EPS-1 could be an alternative to chemical flocculants for treating wastewaters and cyanobacterium-polluted freshwater.

Uncertain behaviours of integrated circuits improve computational performance.

PubMed

Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

2015-11-20

Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance.

Assessing nursing students' knowledge and skills in performing venepuncture and inserting peripheral venous catheters.

PubMed

Ahlin, C; Klang-Söderkvist, B; Johansson, E; Björkholm, M; Löfmark, A

2017-03-01

Venepuncture and the insertion of peripheral venous catheters are common tasks in health care, and training in these procedures is included in nursing programmes. Evidence of nursing students' knowledge and skills in these procedures is limited. The main aim of this study was to assess nursing students' knowledge and skills when performing venepuncture and inserting peripheral venous catheters. Potential associations between level of knowledge and skills, self-training, self-efficacy, and demographic characteristics were also investigated. The assessment was performed by lecturers at a university college in Sweden using the two previously tested instruments "Assess Venepuncture" and "Assess Peripheral Venous Catheter Insertion". Between 81% and 100% of steps were carried out correctly by the students. The step with the highest rating was "Uses gloves", and lowest rating was 'Informs the patients about the possibility of obtaining local anaesthesia'. Significant correlations between degree of self-training and correct performance were found in the group of students who registered their self-training. No associations between demographic characteristics and correct performances were found. Assessing that students have achieved adequate levels of knowledge and skills in these procedures at different levels of the nursing education is of importance to prevent complications and support patient safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sex differences in HIV effects on visual memory among substance-dependent individuals.

PubMed

Keutmann, Michael K; Gonzalez, Raul; Maki, Pauline M; Rubin, Leah H; Vassileva, Jasmin; Martin, Eileen M

2017-08-01

HIV's effects on episodic memory have not been compared systematically between male and female substance-dependent individuals. We administered the Brief Visuospatial Memory Test-Revised (BVMT-R) to 280 substance-dependent HIV+ and HIV- men and women. Groups were comparable on demographic, substance use, and comorbid characteristics. There were no significant main effects of sex or HIV serostatus on BVMT-R performance, but HIV+ women performed significantly more poorly on delayed recall. This effect was most prominent among cocaine-dependent HIV+ women. Our findings are consistent with recent speculation that memory impairment may be more common among HIV+ women, particularly those with a history of cocaine dependence.

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

Kholodnaya, G. E.; Sazonov, R. V.; Ponomarev, D. V.

The paper presents the results of current measurements for the electron beam, propagating inside a drift tube filled in with a gas mixture (Ar and N{sub 2}). The experiments were performed using the TEA-500 pulsed electron accelerator. The main characteristics of electron beam were as follows: 60 ns pulse duration, up to 200 J energy, and 5 cm diameter. The electron beam propagated inside the drift tube assembled of three sections. Gas pressures inside the drift tube were 760 ± 3, 300 ± 3, and 50 ± 1 Torr. The studies were performed in argon, nitrogen, and their mixtures of 33%, 50%, and 66% volume concentrations, respectively.

Specialized data analysis of SSME and advanced propulsion system vibration measurements

NASA Technical Reports Server (NTRS)

Coffin, Thomas; Swanson, Wayne L.; Jong, Yen-Yi

1993-01-01

The basic objectives of this contract were to perform detailed analysis and evaluation of dynamic data obtained during Space Shuttle Main Engine (SSME) test and flight operations, including analytical/statistical assessment of component dynamic performance, and to continue the development and implementation of analytical/statistical models to effectively define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational conditions. This study was to provide timely assessment of engine component operational status, identify probable causes of malfunction, and define feasible engineering solutions. The work was performed under three broad tasks: (1) Analysis, Evaluation, and Documentation of SSME Dynamic Test Results; (2) Data Base and Analytical Model Development and Application; and (3) Development and Application of Vibration Signature Analysis Techniques.

Feedback and the rationing of time and effort among competing tasks.

PubMed

Northcraft, Gregory B; Schmidt, Aaron M; Ashford, Susan J

2011-09-01

The study described here tested a model of how characteristics of the feedback environment influence the allocation of resources (time and effort) among competing tasks. Results demonstrated that performers invest more resources on tasks for which higher quality (more timely and more specific) feedback is available; this effect was partially mediated by task salience and task expectancies. Feedback timing and feedback specificity demonstrated both main and interaction effects on resource allocations. Results also demonstrated that performers do better on tasks for which higher quality feedback is available; this effect was mediated by resources allocated to tasks. The practical and theoretical implications of the role of the feedback environment in managing performance are discussed. PsycINFO Database Record (c) 2011 APA, all rights reserved

Performance Evaluation of Diesel Engine with Preheated Bio Diesel with Additives

NASA Astrophysics Data System (ADS)

Ram Vajja, Sai; Murali, R. B. V.

2016-09-01

This paper mainly reviews about the usage of preheated bio diesel added with 0.5% Etchant as an alternative fuel and evaluates its performance for various blends with different loads. Bio diesel is added with Etchant for rapid combustion as for the bio diesel, the cetane number is high that results in shorter delay of ignition and the mixture is preheated to raise its temperature to improve the combustion process. Analysis of the parameters required to define the combustion characteristics such as IP, BP, ηbth, ηm, ISFC, BSFC, IMEP, MFC, Exhaust Gas Temperature, Heat Release and heat balance is necessary as these values are significant to assess the performance of engine and its emissions of preheated bio diesel.

Performance improvement of organic thin film transistors by using active layer with sandwich structure

NASA Astrophysics Data System (ADS)

Ni, Yao; Zhou, Jianlin; Kuang, Peng; Lin, Hui; Gan, Ping; Hu, Shengdong; Lin, Zhi

2017-08-01

We report organic thin film transistors (OTFTs) with pentacene/fluorinated copper phthalo-cyanine (F16CuPc)/pentacene (PFP) sandwich configuration as active layers. The sandwich devices not only show hole mobility enhancement but also present a well control about threshold voltage and off-state current. By investigating various characteristics, including current-voltage hysteresis, organic film morphology, capacitance-voltage curve and resistance variation of active layers carefully, it has been found the performance improvement is mainly attributed to the low carrier traps and the higher conductivity of the sandwich active layer due to the additional induced carriers in F16CuPc/pentacene. Therefore, using proper multiple active layer is an effective way to gain high performance OTFTs.

Effects of magnetic field strength in the discharge channel on the performance of a multi-cusped field thruster

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

Hu, Peng; Liu, Hui; Gao, Yuanyuan

The performance characteristics of a Multi-cusped Field Thruster depending on the magnetic field strength in the discharge channel were investigated. Four thrusters with different outer diameters of the magnet rings were designed to change the magnetic field strength in the discharge channel. It is found that increasing the magnetic field strength could restrain the radial cross-field electron current and decrease the radial width of main ionization region, which gives rise to the reduction of propellant utilization and thruster performance. The test results in different anode voltage conditions indicate that both the thrust and anode efficiency are higher for the weakermore » magnetic field in the discharge channel.« less

Reproductive Indicators of Leguminous Plants as a Characteristic of the Ecological State of Urban Areas

NASA Astrophysics Data System (ADS)

Zamaletdinov, R. I.; Okulova, S. M.; Gavrilova, E. A.; Zakhvatova, A. A.

2018-01-01

This article examines the results of many years of research on the reproductive performance of six species of leguminous plants (FabaceaeLind., 1836) under conditions of urbanization of habitat (Kazan). The range of variability of the main reproductive indices in six species is illustrated: the potential productivity, the actual productivity of the six main types of leguminous plants. The features of variability of seed death at different stages of development are shown depending on habitat conditions. It is established that the main regularities of changes in reproductive parameters depending on habitat conditions are manifested both in native species and in the introduced species Caraganaarborescens Lam., 1785. Based on the results of the study we made conclusion about the advisability of monitoring the reproductive parameters of leguminous plants for indicating the state of the environment in a large city.

Performance-based Outcomes of Inpatient Rehabilitation Facilities Treating Hip Fracture Patients in the United States

PubMed Central

Baernholdt, Marianne; Anderson, Ruth A.; Merwin, Elizabeth I.

2015-01-01

Objective To examine the influence of facility and aggregate patient characteristics of inpatient rehabilitation facilities (IRFs) on performance-based rehabilitation outcomes in a national sample of IRFs treating Medicare beneficiaries with hip fracture. Design Secondary data analysis. Setting U.S. Medicare-certified IRFs (N=983). Participants 983 US Medicare-certified IRFs. Data included 34,364 patient records of Medicare beneficiaries admitted in 2009 for rehabilitation after hip fracture. Main Outcome Measures Performance-based outcomes included mean motor function on discharge, mean motor change (mean motor score on discharge minus mean motor score on admission) and percentage discharged to the community. Results Higher mean motor function on discharge was explained by aggregate characteristics of hip fracture patients (lower age [p=0.009], lower percentage of Blacks [p<0.001] and Hispanics [p<0.001], higher percentage of females [p<0.030], higher motor function on admission [p<0.001], longer length of stay [p<0.001]) and facility characteristics (freestanding [p<0.001], rural [p<0.001], for-profit [p=0.048], and smaller IRFs [p=0.041]). The findings were similar for motor change, but motor change was also associated with lower mean cognitive function on admission (0.008). Higher percentage discharged to the community was associated with aggregate patient characteristics (lower age [p<0.001], lower percentage of Hispanics [p=0.009], higher percentage of patients living with others [p<0.001], and higher motor function on admission [p<0.001]). No facility characteristics were associated with percentage discharged to the community. Conclusion Performance-based measurement offers health policymakers, administrators, clinicians, and consumers a major opportunity for securing health system improvement by benchmarking or comparing their outcomes to other similar facilities. These results might serve as the basis for benchmarking and quality-based reimbursement to IRFs for one impairment group: hip fracture. PMID:25596000

Characteristics Study of In-Situ Capacitive Sensor for Monitoring Lubrication Oil Debris.

PubMed

Han, Zhibin; Wang, Yishou; Qing, Xinlin

2017-12-08

As an essential part of engine health monitoring (EHM), online lubrication oil debris monitoring has recently received great attention for the assessment of rotating and reciprocating parts in aero-engines, due to its high integration, low cost and safe characteristics. However, it is be a challenge to find a suitable sensor operating in such a complex environment. We present an unconventional novel approach, in which a cylinder capacitive sensor is designed and integrated with the pipeline of an engine lubrication system, so that the capacitive sensor can effectively detect changes in the lubrication oil condition. In this paper, an attempt to illustrate the performance characteristics of the developed cylinder capacitive sensor is made, through an experiment system that simulates a real scenario of a lubrication oil system. The main aim of the research was to qualitatively describe the relationship between the sensor parameter and the lubrication oil debris. In addition, the effect of the temperature and flow rate of the lubrication oil on capacitance change was performed by several experiments and we figured out a compensation method. The experimental results demonstrated that the cylinder capacitive sensor can potentially be used for lubrication oil debris monitoring of the health condition of an aero-engine.

Chemical characteristics and volatile profile of genetically modified peanut cultivars.

PubMed

Ng, Ee Chin; Dunford, Nurhan T; Chenault, Kelly

2008-10-01

Genetic engineering has been used to modify peanut cultivars for improving agronomic performance and pest resistance. Food products developed through genetic engineering have to be assessed for their safety before approval for human consumption. Preservation of desirable chemical, flavor and aroma attributes of the peanut cultivars during the genetic modifications is critical for acceptance of genetically modified peanuts (GMP) by the food industry. Hence, the main objective of this study is to examine chemical characteristics and volatile profile of GMP. The genetically modified peanut cultivars, 188, 540 and 654 were obtained from the USDA-ARS in Stillwater, Oklahoma. The peanut variety Okrun was examined as a control. The volatile analysis was performed using a gas chromatograph/mass spectrometer (GC/MS) equipped with an olfactory detector. The peanut samples were also analyzed for their moisture, ash, protein, sugar and oil compositions. Experimental results showed that the variations in nutritional composition of peanut lines examined in this study were within the values reported for existing cultivars. There were minor differences in volatile profile among the samples. The implication of this study is significant, since it shows that peanut cultivars with greater pest and fungal resistance were successfully developed without major changes in their chemical characteristics.

Stray light characteristics of the diffractive telescope system

NASA Astrophysics Data System (ADS)

Liu, Dun; Wang, Lihua; Yang, Wei; Wu, Shibin; Fan, Bin; Wu, Fan

2018-02-01

Diffractive telescope technology is an innovation solution in construction of large light-weight space telescope. However, the nondesign orders of diffractive optical elements (DOEs) may affect the imaging performance as stray light. To study the stray light characteristics of a diffractive telescope, a prototype was developed and its stray light analysis model was established. The stray light characteristics including ghost, point source transmittance, and veiling glare index (VGI) were analyzed. During the star imaging test of the prototype, the ghost images appeared around the star image as the exposure time of the charge-coupled device improving, consistent with the simulation results. The test result of VGI was 67.11%, slightly higher than the calculated value 57.88%. The study shows that the same order diffraction of the diffractive primary lens and correcting DOE is the main factor that causes ghost images. The stray light sources outside the field of view can illuminate the image plane through nondesign orders diffraction of the primary lens and contributes to more than 90% of the stray light flux on the image plane. In summary, it is expected that these works will provide some guidance for optimizing the imaging performance of diffractive telescopes.

The Physique of Elite Female Artistic Gymnasts: A Systematic Review.

PubMed

Bacciotti, Sarita; Baxter-Jones, Adam; Gaya, Adroaldo; Maia, José

2017-09-01

It has been suggested that successful young gymnasts are a highly select group in terms of the physique. This review summarizes the available literature on elite female gymnasts' anthropometric characteristics, somatotype, body composition and biological maturation. The main aims were to identify: (i) a common physique and (ii) the differences, if any, among competitive/performance levels. A systematic search was conducted online using five different databases. Of 407 putative papers, 17 fulfilled all criteria and were included in the review. Most studies identified similar physiques based on: physical traits (small size and low body mass), a body type (predominance of ecto-mesomorphy), body composition (low fat mass), and maturity status (late skeletal maturity as well as late age-at-menarche). However, there was no consensus as to whether these features predicted competitive performance, or even differentiated between gymnasts within distinctive competitive levels. In conclusion, gymnasts, as a group, have unique pronounced characteristics. These characteristics are likely due to selection for naturally-occurring inherited traits. However, data available for world class competitions were mostly outdated and sample sizes were small. Thus, it was difficult to make any conclusions about whether physiques differed between particular competitive levels.

Heat transfer performance of a pulsating heat pipe charged with acetone-based mixtures

NASA Astrophysics Data System (ADS)

Wang, Wenqing; Cui, Xiaoyu; Zhu, Yue

2017-06-01

Pulsating heat pipes (PHPs) are used as high efficiency heat exchangers, and the selection of working fluids in PHPs has a great impact on the heat transfer performance. This study investigates the thermal resistance characteristics of the PHP charged with acetone-based binary mixtures, where deionized water, methanol and ethanol were added to and mixed with acetone, respectively. The volume mixing ratios were 2:1, 4:1 and 7:1, and the heating power ranged from 10 to 100 W with filling ratios of 45, 55, 62 and 70%. At a low filling ratio (45%), the zeotropic characteristics of the binary mixtures have an influence on the heat transfer performance of the PHP. Adding water, which has a substantially different boiling point compared with that of acetone, can significantly improve the anti-dry-out ability inside the PHP. At a medium filling ratio (55%), the heat transfer performance of the PHP is affected by both phase transition characteristics and physical properties of working fluids. At high heating power, the thermal resistance of the PHP with acetone-water mixture is between that with pure acetone and pure water, whereas the thermal resistance of the PHP with acetone-methanol and acetone-ethanol mixtures at mixing ratios of 2:1 and 4:1 is less than that with the corresponding pure fluids. At high filling ratios (62 and 70%), the heat transfer performance of the PHP is mainly determined by the properties of working fluids that affects the flow resistance. Thus, the PHP with acetone-methanol and acetone-ethanol mixtures that have a lower flow resistance shows better heat transfer performance than that with acetone-water mixture.

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

Wosnik, Martin; Bachant, Pete; Neary, Vincent Sinclair

CACTUS, developed by Sandia National Laboratories, is an open-source code for the design and analysis of wind and hydrokinetic turbines. While it has undergone extensive validation for both vertical axis and horizontal axis wind turbines, and it has been demonstrated to accurately predict the performance of horizontal (axial-flow) hydrokinetic turbines, its ability to predict the performance of crossflow hydrokinetic turbines has yet to be tested. The present study addresses this problem by comparing the predicted performance curves derived from CACTUS simulations of the U.S. Department of Energy’s 1:6 scale reference model crossflow turbine to those derived by experimental measurements inmore » a tow tank using the same model turbine at the University of New Hampshire. It shows that CACTUS cannot accurately predict the performance of this crossflow turbine, raising concerns on its application to crossflow hydrokinetic turbines generally. The lack of quality data on NACA 0021 foil aerodynamic (hydrodynamic) characteristics over the wide range of angles of attack (AoA) and Reynolds numbers is identified as the main cause for poor model prediction. A comparison of several different NACA 0021 foil data sources, derived using both physical and numerical modeling experiments, indicates significant discrepancies at the high AoA experienced by foils on crossflow turbines. Users of CACTUS for crossflow hydrokinetic turbines are, therefore, advised to limit its application to higher tip speed ratios (lower AoA), and to carefully verify the reliability and accuracy of their foil data. Accurate empirical data on the aerodynamic characteristics of the foil is the greatest limitation to predicting performance for crossflow turbines with semi-empirical models like CACTUS. Future improvements of CACTUS for crossflow turbine performance prediction will require the development of accurate foil aerodynamic characteristic data sets within the appropriate ranges of Reynolds numbers and AoA.« less

Prenatal Alcohol Exposure in Rodents As a Promising Model for the Study of ADHD Molecular Basis

PubMed Central

Rojas-Mayorquín, Argelia E.; Padilla-Velarde, Edgar; Ortuño-Sahagún, Daniel

2016-01-01

A physiological parallelism, or even a causal effect relationship, can be deducted from the analysis of the main characteristics of the “Alcohol Related Neurodevelopmental Disorders” (ARND), derived from prenatal alcohol exposure (PAE), and the behavioral performance in the Attention-deficit/hyperactivity disorder (ADHD). These two clinically distinct disease entities, exhibits many common features. They affect neurological shared pathways, and also related neurotransmitter systems. We briefly review here these parallelisms, with their common and uncommon characteristics, and with an emphasis in the subjacent molecular mechanisms of the behavioral manifestations, that lead us to propose that PAE in rats can be considered as a suitable model for the study of ADHD. PMID:28018163

The effects of gamma irradiation on electrical characteristics of Zn/ZnO/n-Si/Au-Sb structure

NASA Astrophysics Data System (ADS)

Salari, M. Abdolahpour; Güzeldir, B.; Saǧlam, M.

2018-02-01

In this research, we have investigated the electrical characteristics of Zn/ZnO/n-Si/Au-Sb structure before and after 60Co gamma (γ)-ray source irradiation with the total dose range of 0-500 kGy at room temperature. Electrical measurements of this structure have been performed using current-voltage (I-V) and capacitance-voltage (C-V) techniques. Experimental results show that the values of the ideality factor obtained from I-V measurements increased and the values of the barrier height obtained from reverse-bias C-V measurements decreased after gamma-irradiation. The results show that the main effect of the radiation is the generation of laterally inhomogeneous defects near the semiconductor surface.

Experimental evaluation of battery cells for space-based radar application

NASA Technical Reports Server (NTRS)

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

A test program was conducted to characterize five space-quality nickel-hydrogen (NiH2) battery cells. A subset of those tests was also done on five commercial nickel-cadmium (NiCd) cells, for correlation to the characteristics of an Energy Storage Unit Simulator. The test program implemented the recommendations of a 1991 study, as reported to IECEC-92. The findings of the tests are summarized, and expected impacts on the performance of the electrical power system (EPS) of a large space-based radar (SBR) surveillance satellite are derived. The main characteristics examined and compared were terminal voltage (average and transient) and capacity through discharge, equivalent series resistance, derived inductance and capacitance, charge return efficiency, and inter-pulse charge effectiveness.

A review of automatic mass detection and segmentation in mammographic images.

PubMed

Oliver, Arnau; Freixenet, Jordi; Martí, Joan; Pérez, Elsa; Pont, Josep; Denton, Erika R E; Zwiggelaar, Reyer

2010-04-01

The aim of this paper is to review existing approaches to the automatic detection and segmentation of masses in mammographic images, highlighting the key-points and main differences between the used strategies. The key objective is to point out the advantages and disadvantages of the various approaches. In contrast with other reviews which only describe and compare different approaches qualitatively, this review also provides a quantitative comparison. The performance of seven mass detection methods is compared using two different mammographic databases: a public digitised database and a local full-field digital database. The results are given in terms of Receiver Operating Characteristic (ROC) and Free-response Receiver Operating Characteristic (FROC) analysis. Copyright 2009 Elsevier B.V. All rights reserved.

Make-to-order manufacturing - new approach to management of manufacturing processes

NASA Astrophysics Data System (ADS)

Saniuk, A.; Waszkowski, R.

2016-08-01

Strategic management must now be closely linked to the management at the operational level, because only in such a situation the company can be flexible and can quickly respond to emerging opportunities and pursue ever-changing strategic objectives. In these conditions industrial enterprises seek constantly new methods, tools and solutions which help to achieve competitive advantage. They are beginning to pay more attention to cost management, economic effectiveness and performance of business processes. In the article characteristics of make-to-order systems (MTO) and needs associated with managing such systems is identified based on the literature analysis. The main aim of this article is to present the results of research related to the development of a new solution dedicated to small and medium enterprises manufacture products solely on the basis of production orders (make-to- order systems). A set of indicators to enable continuous monitoring and control of key strategic areas this type of company is proposed. A presented solution includes the main assumptions of the following concepts: the Performance Management (PM), the Balanced Scorecard (BSC) and a combination of strategic management with the implementation of operational management. The main benefits of proposed solution are to increase effectiveness of MTO manufacturing company management.

Forensic applications of supercritical fluid chromatography - mass spectrometry.

PubMed

Pauk, Volodymyr; Lemr, Karel

2018-06-01

Achievements of supercritical fluid chromatography with mass spectrometric detection made in the field of forensic science during the last decade are reviewed. The main topics include analysis of traditional drugs of abuse (e.g. cannabis, methamphetamine) as well as new psychoactive substances (synthetic cannabinoids, cathinones and phenethylamines), doping agents (anabolic steroids, stimulants, diuretics, analgesics etc.) and chemical warfare agents. Control of food authenticity, detection of adulteration and identification of toxic substances in food are also pointed out. Main aspects of an analytical workflow, such as sample preparation, separation and detection are discussed. A special attention is paid to the performance characteristics and validation parameters of supercritical fluid chromatography-mass spectrometric methods in comparison with other separation techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

Satisfaction Determinants of Women during Childbirth in Health Facilities in Senegal: Literature Review.

PubMed

Ball Anne, Thierno Souleymane; Diouf, Massamba; Seck, Ibrahima; Tal Dia, Anta

2017-03-01

This article presents the results of the literature review performed on the main conceptual models used in the measurement of the satisfaction of women during childbirth in health facilities and the main determinants of their satisfaction. The review focused on PubMed, Google scholar and Public Health data. Several conceptual models for measuring satisfaction were found through the literature. It is clear from this review that a multitude of determinants are associated with women's satisfaction such as health care provider's attitude, the environment as well as the socio-demographic, economic and even psychological characteristics of the patient herself. These results were used to develop a conceptual framework for measuring the satisfaction of women who gave birth in Senegal health facilities.

The prevalence and severity of oral impacts on daily performances in Thai primary school children

PubMed Central

Gherunpong, Sudaduang; Tsakos, Georgios; Sheiham, Aubrey

2004-01-01

Background Traditional methods of measuring oral health mainly use clinical dental indices and have been complemented by oral health related quality of life (OHRQoL) measures. Most OHRQoL studies have been on adults and elderly populations. There are no systematic OHRQoL studies of a population-based sample of children. The objective of this study was to assess the prevalence, characteristics and severity of oral impacts in primary school children. Methods Cross-sectional study of all 1126 children aged 11–12 years in a municipal area of Suphanburi province, Thailand. An OHRQoL measure, Child-Oral Impacts on Daily Performances index (Child-OIDP) was used to assess oral impacts. Children were also clinically examined and completed a self-administered questionnaire about demographic information and oral behaviours. Results 89.8% of children had one or more oral impacts. The median impact score was 7.6 and mean score was 8.8. Nearly half (47.0%) of the children with impacts had impacts at very little or little levels of intensity. Most (84.8%) of those with impacts had 1–4 daily performances affected (out of 8 performances). Eating was the most common performance affected (72.9%). The severity of impacts was high for eating and smiling and low for study and social contact performances. The main clinical causes of impacts were sensitive tooth (27.9%), oral ulcers (25.8%), toothache (25.1%) and an exfoliating primary tooth (23.4%). Conclusions The study reveals that oral health impacts on quality of life in Thai primary school children. Oral impacts were prevalent, but not severe. The impacts mainly related to difficulty eating and smiling. Toothache, oral ulcers and natural processes contributed largely to the incidence of oral impacts. PMID:15476561

Key demands and characteristics of occupations performed by individuals with spinal cord injury living in Switzerland.

PubMed

Nützi, M; Trezzini, B; Ronca, E; Schwegler, U

2017-08-08

Descriptive qualitative and quantitative study using cross-sectional data from the Swiss Spinal Cord Injury Cohort Study (SwiSCI). To determine the key demands and characteristics of occupations performed by individuals with spinal cord injury (SCI). Swiss community. Job titles indicated by SwiSCI participants were linked to occupational titles from the Occupational Information Network (O*NET) and then frequency-analyzed across sociodemographic and injury-related factors. Subsequently, average O*NET relevance values ranging from 0 to 100 were calculated for the occupations' demands and characteristics, both in general and stratified by injury-related factors. The 1549 study participants indicated a total of 717 job titles and were primarily employed in administrative and management occupations (22.1% and 16.4%, respectively). The participants' occupations predominantly required verbal abilities (average relevance [AR]=68.4) and complex problem solving skills (AR=55.8) and were characterized by conventional work tasks (AR=62.9) and social relationships (AR=58.6). Both the occupations' frequency distribution as well as the average relevance levels of their demands and characteristics differed by SCI severity. Individuals with SCI perform a broad range of occupations that are mainly characterized by cognitive and communicative demands, while physical demands are of minor importance. By informing the development of job matching profiles for vocational guidance, our study facilitates the determination of well-matching jobs for persons with SCI and may contribute to a more sustainable return to work of the affected persons.Spinal Cord advance online publication, 8 August 2017; doi:10.1038/sc.2017.84.

Physico-mechanical properties of a brick based with sand of dunes stabilized by hydraulic lime

NASA Astrophysics Data System (ADS)

Djouhri, Mohamed; Bentebba, Mohamed Taher

2017-02-01

Brick establishment is an essential and elementary cell in any construction. In this study, bricks in mortar with sand of dunes (BRSD) were made and submitted to the various trials of characterization. The addition of hydraulic lime according to progressive rates allowed following the influence of the dosage of the latter on the physical characteristics and on the mechanical performances of bricks according to several formulations. The experimental method of formulation is mainly based on the optimization of materials constituting the hydraulic lime and the sand dunes, with the aim of reaching a new composition to enjoy physico-mechanical characteristics wishes. The various realized tries showed that the addition of lime, in a certain interval, possesses an important influence on the physic-mechanical performances of bricks in particular the mechanical resistance and the heat insulation, for a dosage of 30 % of hydraulic lime, the compression resistance of the brick is 8 MPa with a thermal conductivity of 1.7 W/m°C.

Characterizing complexity in socio-technical systems: a case study of a SAMU Medical Regulation Center.

PubMed

Righi, Angela Weber; Wachs, Priscila; Saurin, Tarcísio Abreu

2012-01-01

Complexity theory has been adopted by a number of studies as a benchmark to investigate the performance of socio-technical systems, especially those that are characterized by relevant cognitive work. However, there is little guidance on how to assess, systematically, the extent to which a system is complex. The main objective of this study is to carry out a systematic analysis of a SAMU (Mobile Emergency Medical Service) Medical Regulation Center in Brazil, based on the core characteristics of complex systems presented by previous studies. The assessment was based on direct observations and nine interviews: three of them with regulator of emergencies medical doctor, three with radio operators and three with telephone attendants. The results indicated that, to a great extent, the core characteristics of complexity are magnified) due to basic shortcomings in the design of the work system. Thus, some recommendations are put forward with a view to reducing unnecessary complexity that hinders the performance of the socio-technical system.

Performance evaluation of bottom gate ZnO based thin film transistors with different W/L ratios for UV sensing

NASA Astrophysics Data System (ADS)

Varma, Tarun; Periasamy, C.; Boolchandani, Dharmendar

2018-02-01

In this paper, we report the simulation, fabrication and characterisation of UV photo-detectors with bottom gate ZnO Thin Film Transistors (TFTs), grown on silicon at room temperature using RF magnetron sputtering process. The static performance of these detectors have been explored by varying the channel lengths (6 μm and 12 μm). The fabricated devices show low leakage currents with threshold voltages of 1.18 & 2.33 V, sub-threshold swings of 13.5 & 12.8 V/dec for channel lengths of 6 μm and 12 μm TFT, respectively. They also exhibit superior electrical characteristics with an ON-OFF ratio of the order of 3. The detector was also tested for device stability, with the transfer characteristics of the TFTs, which got deteriorated mainly by the negative bias-stress. The TFTs were further tested for UV detector applications and found to exhibit good photo-response.

Multibeam Antenna Design and Development for NASA Advanced Communications Technology Satellite (ACTS)

NASA Technical Reports Server (NTRS)

Choung, Youn H.; Wong, William C.

1986-01-01

The design of the ACTS multibeam antenna is described, and its performance is evaluated. The multibeam antenna is designed to cover the continential U.S. and provides three fixed spot beams for high burst rate operations and two scanning beams for low burst rate operations. The antenna has one main reflector, a dual polarized subreflector, and two orthogonal feed assemblies. The feed system is to receive a linearly polarized communication signal from 28.9-30.0 GHz and to provide the elevation and azimuth error tracking signals at 29.975 GHz with a 0.01 deg tracking accuracy. The feed system uses a single multiflare conical horn and a multimode coupler to provide a symmetric primary pattern for the communication signal. The sidelobe characteristics of the reflector, and the relation between the sidelobe level and surface distortion are studied. It is noted that the performance measurements for the multibeam antenna correlate well with predictions for secondary patterns and scan characteristics.

Factors that influence public awareness of domestic waste characteristics and management in rural areas.

PubMed

Han, Zhiyong; Duan, Qingqing; Fei, Yongqiang; Zeng, Dan; Shi, Guozhong; Li, Haimei; Hu, Meilun

2018-05-01

Public awareness of domestic waste characteristics and management (PADWCM) is a prerequisite for a domestic waste management (DWM) plan. In this study, we considered China as a typical example of developing countries to investigate the public perception of environmental pollution (PEP), its PADWCM, and its socioeconomic factors, using questionnaires and statistical methods. The results indicated that the public PEP was mainly due to obvious environmental contamination in local villages, and the PADWCM is still inadequate in rural areas. However, 83.9% of the respondents agreed that DWM is highly necessary. The PADWCM, including the hazard, recyclability, and characteristic pollution caused by domestic waste, was learned mainly from people's direct PEP, experiences, and repurchasing by recyclers. Education period had highly significant positive correlations and regressions with PEP and PADWCM, respectively. Additionally, education directly affected public awareness in different income and age groups. Demonstration projects had a significant positive effect on the awareness of characteristic pollution caused by domestic waste, which was readily perceived. Propaganda had a significant positive influence on the awareness of treatment necessity. Age and gender had no obvious effects on public PEP and PADWCM. Some aspects of PADWCM requiring a deep understanding became stronger as income increased; however, the PADWCM located close to poor people became weaker. Some aspects of PEP could significantly influence the awareness of characteristic pollution caused by domestic waste and awareness of treatment necessity. Therefore, improving environmental education, performing demonstration projects and effective environmental propaganda, increasing people's income, and attracting young people to participate in DWM will be important for enhancing environmental awareness and DWM in rural areas. Integr Environ Assess Manag 2018;14:395-406. © 2018 SETAC. © 2018 SETAC.

Investigation of the impact of main control room digitalization on operators cognitive reliability in nuclear power plants.

PubMed

Zhou, Yong; Mu, Haiying; Jiang, Jianjun; Zhang, Li

2012-01-01

Currently, there is a trend in nuclear power plants (NPPs) toward introducing digital and computer technologies into main control rooms (MCRs). Safe generation of electric power in NPPs requires reliable performance of cognitive tasks such as fault detection, diagnosis, and response planning. The digitalization of MCRs has dramatically changed the whole operating environment, and the ways operators interact with the plant systems. If the design and implementation of the digital technology is incompatible with operators' cognitive characteristics, it may have negative effects on operators' cognitive reliability. Firstly, on the basis of three essential prerequisites for successful cognitive tasks, a causal model is constructed to reveal the typical human performance issues arising from digitalization. The cognitive mechanisms which they impact cognitive reliability are analyzed in detail. Then, Bayesian inference is used to quantify and prioritize the influences of these factors. It suggests that interface management and unbalanced workload distribution have more significant impacts on operators' cognitive reliability.

Agronomic, chemical and genetic profiles of hot peppers (Capsicum annuum ssp.).

PubMed

De Masi, Luigi; Siviero, Pietro; Castaldo, Domenico; Cautela, Domenico; Esposito, Castrese; Laratta, Bruna

2007-08-01

A study on morphology, productive yield, main quality parameters and genetic variability of eight landraces of hot pepper (Capsicum annuum ssp.) from Southern Italy has been performed. Morphological characters of berries and productivity values were evaluated by agronomic analyses. Chemical and genetic investigations were performed by HPLC and random amplified polymorphic DNA (RAPD)-PCR, respectively. In particular, carotenoid and capsaicinoid (pungency) contents were considered as main quality parameters of hot pepper. For the eight selected samples, genetic similarity values were calculated from the generated RAPD fragments and a dendrogram of genetic similarity was constructed. All the eight landraces exhibited characteristic RAPD patterns that allowed their characterization. Agro-morphological and chemical determinations were found to be adequate for selection, but they resulted useful only for plants grown in the same environmental conditions. RAPD application may provide a more reliable way based on DNA identification. The results of our study led to the identification of three noteworthy populations, suitable for processing, which fitted into different clusters of the dendrogram.

Recent Advances in Metal Chalcogenides (MX; X = S, Se) Nanostructures for Electrochemical Supercapacitor Applications: A Brief Review

PubMed Central

Theerthagiri, Jayaraman; Durai, Govindarajan; Rana, Abu ul Hassan Sarwar; Sangeetha, Kirubanandam; Kuppusami, Parasuraman; Kim, Hyun-Seok

2018-01-01

Supercapacitors (SCs) have received a great deal of attention and play an important role for future self-powered devices, mainly owing to their higher power density. Among all types of electrical energy storage devices, electrochemical supercapacitors are considered to be the most promising because of their superior performance characteristics, including short charging time, high power density, safety, easy fabrication procedures, and long operational life. An SC consists of two foremost components, namely electrode materials, and electrolyte. The selection of appropriate electrode materials with rational nanostructured designs has resulted in improved electrochemical properties for high performance and has reduced the cost of SCs. In this review, we mainly spotlight the non-metallic oxide, especially metal chalcogenides (MX; X = S, Se) based nanostructured electrode materials for electrochemical SCs. Different non-metallic oxide materials are highlighted in various categories, such as transition metal sulfides and selenides materials. Finally, the designing strategy and future improvements on metal chalcogenide materials for the application of electrochemical SCs are also discussed. PMID:29671823

A stochastic hybrid model for pricing forward-start variance swaps

NASA Astrophysics Data System (ADS)

Roslan, Teh Raihana Nazirah

2017-11-01

Recently, market players have been exposed to the astounding increase in the trading volume of variance swaps. In this paper, the forward-start nature of a variance swap is being inspected, where hybridizations of equity and interest rate models are used to evaluate the price of discretely-sampled forward-start variance swaps. The Heston stochastic volatility model is being extended to incorporate the dynamics of the Cox-Ingersoll-Ross (CIR) stochastic interest rate model. This is essential since previous studies on variance swaps were mainly focusing on instantaneous-start variance swaps without considering the interest rate effects. This hybrid model produces an efficient semi-closed form pricing formula through the development of forward characteristic functions. The performance of this formula is investigated via simulations to demonstrate how the formula performs for different sampling times and against the real market scenario. Comparison done with the Monte Carlo simulation which was set as our main reference point reveals that our pricing formula gains almost the same precision in a shorter execution time.

Programming Tools: Status, Evaluation, and Comparison

NASA Technical Reports Server (NTRS)

Cheng, Doreen Y.; Cooper, D. M. (Technical Monitor)

1994-01-01

In this tutorial I will first describe the characteristics of scientific applications and their developers, and describe the computing environment in a typical high-performance computing center. I will define the user requirements for tools that support application portability and present the difficulties to satisfy them. These form the basis of the evaluation and comparison of the tools. I will then describe the tools available in the market and the tools available in the public domain. Specifically, I will describe the tools for converting sequential programs, tools for developing portable new programs, tools for debugging and performance tuning, tools for partitioning and mapping, and tools for managing network of resources. I will introduce the main goals and approaches of the tools, and show main features of a few tools in each category. Meanwhile, I will compare tool usability for real-world application development and compare their different technological approaches. Finally, I will indicate the future directions of the tools in each category.

Fault-tolerant optimised tracking control for unknown discrete-time linear systems using a combined reinforcement learning and residual compensation methodology

NASA Astrophysics Data System (ADS)

Han, Ke-Zhen; Feng, Jian; Cui, Xiaohong

2017-10-01

This paper considers the fault-tolerant optimised tracking control (FTOTC) problem for unknown discrete-time linear system. A research scheme is proposed on the basis of data-based parity space identification, reinforcement learning and residual compensation techniques. The main characteristic of this research scheme lies in the parity-space-identification-based simultaneous tracking control and residual compensation. The specific technical line consists of four main contents: apply subspace aided method to design observer-based residual generator; use reinforcement Q-learning approach to solve optimised tracking control policy; rely on robust H∞ theory to achieve noise attenuation; adopt fault estimation triggered by residual generator to perform fault compensation. To clarify the design and implementation procedures, an integrated algorithm is further constructed to link up these four functional units. The detailed analysis and proof are subsequently given to explain the guaranteed FTOTC performance of the proposed conclusions. Finally, a case simulation is provided to verify its effectiveness.

The microgravity environment of the D1 mission

NASA Technical Reports Server (NTRS)

Hamacher, H.; Merbold, U.; Jilg, R.

1990-01-01

Some characteristic features and results of D1 microgravity measurements are discussed as performed in the Material Science Double Rack (MSDR) and the Materials Science Double Rack for Experiment Modules and Apparatus (MEDEA). Starting with a brief review of the main potential disturbances, the payload aspects of interest to the analysis and the accelerometer measuring systems are described. The microgravity data are analyzed with respect to selected mission events such as thruster firings for attitude control, operations of Spacelab experiment facilities, vestibular experiments and crew activities. The origins are divided into orbit, vehicle, and experiment induced perturbations. It has been found that the microgravity-environment is dictated mainly by payload-induced perturbations. To reduce the microgravity-level, the design of some experiment facilities has to be improved by minimizing the number of moving parts, decoupling of disturbing units from experiment facilities, by taking damping measures, etc. In addition, strongly disturbing experiments and very sensitive investigations should be performed in separate mission phases.

Novel localized heating technique on centrifugal microfluidic disc with wireless temperature monitoring system.

PubMed

Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman

2015-01-01

Recent advances in the field of centrifugal microfluidic disc suggest the need for electrical interface in the disc to perform active biomedical assays. In this paper, we have demonstrated an active application powered by the energy harvested from the rotation of the centrifugal microfluidic disc. A novel integration of power harvester disc onto centrifugal microfluidic disc to perform localized heating technique is the main idea of our paper. The power harvester disc utilizing electromagnetic induction mechanism generates electrical energy from the rotation of the disc. This contributes to the heat generation by the embedded heater on the localized heating disc. The main characteristic observed in our experiment is the heating pattern in relative to the rotation of the disc. The heating pattern is monitored wirelessly with a digital temperature sensing system also embedded on the disc. Maximum temperature achieved is 82 °C at rotational speed of 2000 RPM. The technique proves to be effective for continuous heating without the need to stop the centrifugal motion of the disc.

Dynamic Characteristics of Green Sandstone Subjected to Repetitive Impact Loading: Phenomena and Mechanisms

NASA Astrophysics Data System (ADS)

Li, S. H.; Zhu, W. C.; Niu, L. L.; Yu, M.; Chen, C. F.

2018-06-01

A split Hopkinson pressure bar apparatus driven by a pendulum hammer was used to perform uniaxial compression tests to examine the degradation process of green sandstone subjected to repetitive impact loading. The acoustic characteristics, dissipated energy, deformation characteristics, and microstructure evolution were investigated. The representative stress-strain curve can be broken into five stages that were characterized by changes in the axial strain response during impact loading. Both the ultrasonic wave velocity and cumulative dissipated energy exhibited obvious three-stage behavior with respect to the impact number. As the impact number increased, more than one peak was observed in the frequency spectra, and the relative weight of the peak frequency increased in the low-frequency range. According to the evolution of the ultrasonic wave velocity, the degradation process was divided into three stages. By comparing the intact stage I and early stage II microcrack development patterns, the initiation of new cracks and elongation of existing cracks were identified as the main degradation mechanisms. Furthermore, a slight increase in the number of cracks was observed, and microcrack lengths steadily increased. Moreover, due to the low level of microcrack damage, the deformation mechanism was mainly characterized by volume compression during impact loading. In late stage II, the main degradation mechanism was the elongation of existing cracks. Additionally, as microcracks accumulated in the rock samples, cracks were arranged parallel to the loading direction, which led to volume dilation. In stage III, microcracks continued to elongate nearly parallel to the loading direction and then linked to each other, which led to intense degradation in the rock samples. In this stage, rock sample deformation was mainly characterized by volume dilation during impact loading. Finally, rock samples were split into blocks with fractures oriented subparallel to the loading direction. These results can improve the understanding of the stability evaluations of rock structures subjected to repetitive impact loading.

The SANS facility at the Pitesti 14MW TRIGA reactor

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

Ionita, I.; Grabcev, B.; Todireanu, S.

2006-12-15

The SANS facility existing at the Pitesti 14MW TRIGA reactor is presented. The main characteristics and the preliminary evaluation of the installation performances are given. A monochromatic neutron beam with 1.5 A {<=} {lambda} {<=} 5 A is produced by a mechanical velocity selector with helical slots. A fruitful partnership was established between INR Pitesti (Romania) and JINR Dubna (Russia). The first step in this cooperation consists in the manufacturing in Dubna of a battery of gas-filled positional detectors devoted to the SANS instrument.

238U Mössbauer study on the magnetic properties of uranium-based heavy fermion superconductors

NASA Astrophysics Data System (ADS)

Tsutsui, Satoshi; Nakada, Masami; Nasu, Saburo; Haga, Yoshinori; Honma, Tetsuo; Yamamoto, Etsuji; Ohkuni, Hitoshi; Ōnuki, Yoshichika

2000-07-01

We have performed 238U Mössbauer spectroscopy of uranium-based heavy fermion superconductors, UPd2Al3 and URu2Si2, in order to investigate their physical properties, mainly their magnetic properties. The slow relaxation of magnetic hyperfine interaction in a paramagnetic state and the static hyperfine field has been observed in an antiferromagnetic ordered state for each compound. The line-widths have maximum at their characteristic temperatures where their magnetic susceptibilities have maximum values.

Uncertainty analysis of thermal quantities measurement in a centrifugal compressor

NASA Astrophysics Data System (ADS)

Hurda, Lukáš; Matas, Richard

2017-09-01

Compressor performance characteristics evaluation process based on the measurement of pressure, temperature and other quantities is examined to find uncertainties for directly measured and derived quantities. CFD is used as a tool to quantify the influences of different sources of uncertainty of measurements for single- and multi-thermocouple total temperature probes. The heat conduction through the body of the thermocouple probe and the heat-up of the air in the intake piping are the main phenomena of interest.

Application of the enhanced homotopy perturbation method to solve the fractional-order Bagley-Torvik differential equation

NASA Astrophysics Data System (ADS)

Zolfaghari, M.; Ghaderi, R.; Sheikhol Eslami, A.; Ranjbar, A.; Hosseinnia, S. H.; Momani, S.; Sadati, J.

2009-10-01

The enhanced homotopy perturbation method (EHPM) is applied for finding improved approximate solutions of the well-known Bagley-Torvik equation for three different cases. The main characteristic of the EHPM is using a stabilized linear part, which guarantees the stability and convergence of the overall solution. The results are finally compared with the Adams-Bashforth-Moulton numerical method, the Adomian decomposition method (ADM) and the fractional differential transform method (FDTM) to verify the performance of the EHPM.

[E-learning and the continuing professional development in medicine].

PubMed

De Fiore, Luca

2010-06-01

E-learning is widely used in continuing medical education but three main problems still face health decision makers: the substantial heterogeneity among the characteristics of the web-based educational projects; the concerns about the e-learning effectiveness; the variety of outcomes used to evaluate the effectiveness. Systematic reviews suggest e-learning has effectiveness similar to traditional educational methods.The attention should now be given to how and when can we use e-learning to improve the health workers' performance and better healthcare.

Data Reduction and Control Software for Meteor Observing Stations Based on CCD Video Systems

NASA Technical Reports Server (NTRS)

Madiedo, J. M.; Trigo-Rodriguez, J. M.; Lyytinen, E.

2011-01-01

The SPanish Meteor Network (SPMN) is performing a continuous monitoring of meteor activity over Spain and neighbouring countries. The huge amount of data obtained by the 25 video observing stations that this network is currently operating made it necessary to develop new software packages to accomplish some tasks, such as data reduction and remote operation of autonomous systems based on high-sensitivity CCD video devices. The main characteristics of this software are described here.

Investigation of fiber dispersion impairment in 400GbE discrete multi-tone system for reach enhancement up to 40 km

NASA Astrophysics Data System (ADS)

Okabe, Ryo; Tanaka, Toshiki; Nishihara, Masato; Kai, Yutaka; Takahara, Tomoo; Chen, Hao; Yan, Weizhen; Tao, Zhenning; Rasmussen, Jens C.

2015-01-01

Discrete multi-tone (DMT) technology is an attractive modulation technique for short reach optical transmission system. One of the main factors that limit system performance is fiber dispersion, which is strongly influenced by the chirp characteristics of transmitters. We investigated the fiber dispersion impairment in a 400GbE (4 × 116.1-Gb/s) DMT system on LAN-WDM grid for reach enhancement up to 40 km through experiments and numerical simulations.

Aerodynamics on a transport aircraft type wing-body model

NASA Technical Reports Server (NTRS)

Schmitt, V.

1982-01-01

The DFLR-F4 wing-body combination is studied. The 1/38 model is formed by a 9.5 aspect ratio transonic wing and an Airbus A 310 fuselage. The F4 wing geometrical characteristics are described and the main experimental results obtained in the S2MA wind tunnel are discussed. Both wing-fuselage interferences and viscous effects, which are important on the wing due to a high rear loading, are investigated by performing 3D calculations. An attempt is made to find their limitations.

Degradable Bone Graft Substitute for Effective Delivery of Multiple Growth Factors in the Treatment of Nonunion Fractures

DTIC Science & Technology

2012-08-01

growth factors directly to the bone defect site can enhance repair of non-union fractures. In this study, a new chitosan /xylan composite hydrogel was...delivery aspect of this study did not succeed, treatment with the new xylan/ chitosan hydrogel alone was enough to heal serious fractures that did not...characteristics of the hydrogel in question could be tested as well as performing in vitro cell work. The previous supplier of chitosan , the main polymer

Evaluation of natural language processing systems: Issues and approaches

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

Guida, G.; Mauri, G.

This paper encompasses two main topics: a broad and general analysis of the issue of performance evaluation of NLP systems and a report on a specific approach developed by the authors and experimented on a sample test case. More precisely, it first presents a brief survey of the major works in the area of NLP systems evaluation. Then, after introducing the notion of the life cycle of an NLP system, it focuses on the concept of performance evaluation and analyzes the scope and the major problems of the investigation. The tools generally used within computer science to assess the qualitymore » of a software system are briefly reviewed, and their applicability to the task of evaluation of NLP systems is discussed. Particular attention is devoted to the concepts of efficiency, correctness, reliability, and adequacy, and how all of them basically fail in capturing the peculiar features of performance evaluation of an NLP system is discussed. Two main approaches to performance evaluation are later introduced; namely, black-box- and model-based, and their most important characteristics are presented. Finally, a specific model for performance evaluation proposed by the authors is illustrated, and the results of an experiment with a sample application are reported. The paper concludes with a discussion on research perspective, open problems, and importance of performance evaluation to industrial applications.« less

Nutritional impact of inflammatory bowel diseases on children and adolescents☆

PubMed Central

dos Santos, Gilton Marques; Silva, Luciana Rodrigues; Santana, Genoile Oliveira

2014-01-01

OBJECTIVE: To perform a sistematiy review of the literature about the nutritional impact of inflammatory bowel diseases in children and adolescents. DATA SOURCES: A systematic review was performed using PubMed/MEDLINE, LILACS and SciELO databases, with inclusion of articles in Portuguese and in English with original data, that analyzed nutritional aspects of inflammatory bowel diseases in children and adolescents. The initial search used the terms "inflammatory bowel diseases" and "children" or "adolescents" and "nutritional evaluation" or "nutrition deficiency". The selection of studies was initially performed by reading the titles and abstracts. Review studies and those withouth data for pediatric patients were excluded. Subsequently, the full reading of the articles considered relevant was performed. RESULTS: 237 studies were identified, and 12 of them were selected according to the inclusion criteria. None of them was performed in South America. During the analysis of the studies, it was observed that nutritional characteristics of patients with inflammatory bowel disease may be altered; the main reports were related to malnutrition, growth stunting, delayed puberty and vitamin D deficiency. CONCLUSION: There are nutritional consequences of inflammatory bowel diseases in children and adolescents, mainly growth stunting, slower pubertal development, underweight and vitamin deficiencies. Nutritional impairments were more significant in patients with Crohn's disease; overweight and obesity were more common in patients with ulcerative rectocolitis. A detailed nutritional assessment should be performed periodically in children and adolescents with inflammatory bowel disease. PMID:25511006

Definition of perspective scheme of organization of traffic using methods of forecasting and modeling

NASA Astrophysics Data System (ADS)

Vlasov, V. M.; Novikov, A. N.; Novikov, I. A.; Shevtsova, A. G.

2018-03-01

In the environment of highly developed urban agglomerations, one of the main problems arises - inability of the road network to reach a high level of motorization. The introduction of intelligent transport systems allows solving this problem, but the main issue in their implementation remains open: to what extent this or that method of improving the transport network will be effective and whether it is able to solve the problem of vehicle growth especially for the long-term period. The main goal of this work was the development of an approach to forecasting the increase in the intensity of traffic flow for a long-term period using the population and the level of motorization. The developed approach made it possible to determine the projected population and, taking into account the level of motorization, to determine the growth factor of the traffic flow intensity, which allows calculating the intensity value for a long-term period with high accuracy. The analysis of the main methods for predicting the characteristics of the transport stream is performed. The basic values and parameters necessary for their use are established. The analysis of the urban settlement is carried out and the level of motorization characteristic for the given locality is determined. A new approach to predicting the intensity of the traffic flow has been developed, which makes it possible to predict the change in the transport situation in the long term in high accuracy. Calculations of the magnitude of the intensity increase on the basis of the developed forecasting method are made and the errors in the data obtained are determined. The main recommendations on the use of the developed forecasting approach for the long-term functioning of the road network are formulated.

Strategies to Achieve High-Performance White Organic Light-Emitting Diodes

PubMed Central

Zhang, Lirong; Li, Xiang-Long; Luo, Dongxiang; Xiao, Peng; Xiao, Wenping; Song, Yuhong; Ang, Qinshu; Liu, Baiquan

2017-01-01

As one of the most promising technologies for next-generation lighting and displays, white organic light-emitting diodes (WOLEDs) have received enormous worldwide interest due to their outstanding properties, including high efficiency, bright luminance, wide viewing angle, fast switching, lower power consumption, ultralight and ultrathin characteristics, and flexibility. In this invited review, the main parameters which are used to characterize the performance of WOLEDs are introduced. Subsequently, the state-of-the-art strategies to achieve high-performance WOLEDs in recent years are summarized. Specifically, the manipulation of charges and excitons distribution in the four types of WOLEDs (fluorescent WOLEDs, phosphorescent WOLEDs, thermally activated delayed fluorescent WOLEDs, and fluorescent/phosphorescent hybrid WOLEDs) are comprehensively highlighted. Moreover, doping-free WOLEDs are described. Finally, issues and ways to further enhance the performance of WOLEDs are briefly clarified. PMID:29194426

Performance characteristics of five triage tools for major incidents involving traumatic injuries to children.

PubMed

Price, C L; Brace-McDonnell, S J; Stallard, N; Bleetman, A; Maconochie, I; Perkins, G D

2016-05-01

Context Triage tools are an essential component of the emergency response to a major incident. Although fortunately rare, mass casualty incidents involving children are possible which mandate reliable triage tools to determine the priority of treatment. To determine the performance characteristics of five major incident triage tools amongst paediatric casualties who have sustained traumatic injuries. Retrospective observational cohort study using data from 31,292 patients aged less than 16 years who sustained a traumatic injury. Data were obtained from the UK Trauma Audit and Research Network (TARN) database. Interventions Statistical evaluation of five triage tools (JumpSTART, START, CareFlight, Paediatric Triage Tape/Sieve and Triage Sort) to predict death or severe traumatic injury (injury severity score >15). Main outcome measures Performance characteristics of triage tools (sensitivity, specificity and level of agreement between triage tools) to identify patients at high risk of death or severe injury. Of the 31,292 cases, 1029 died (3.3%), 6842 (21.9%) had major trauma (defined by an injury severity score >15) and 14,711 (47%) were aged 8 years or younger. There was variation in the performance accuracy of the tools to predict major trauma or death (sensitivities ranging between 36.4 and 96.2%; specificities 66.0-89.8%). Performance characteristics varied with the age of the child. CareFlight had the best overall performance at predicting death, with the following sensitivity and specificity (95% CI) respectively: 95.3% (93.8-96.8) and 80.4% (80.0-80.9). JumpSTART was superior for the triaging of children under 8 years; sensitivity and specificity (95% CI) respectively: 86.3% (83.1-89.5) and 84.8% (84.2-85.5). The triage tools were generally better at identifying patients who would die than those with non-fatal severe injury. This statistical evaluation has demonstrated variability in the accuracy of triage tools at predicting outcomes for children who sustain traumatic injuries. No single tool performed consistently well across all evaluated scenarios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Class modality, student characteristics, and performance in a community college introductory STEM course

NASA Astrophysics Data System (ADS)

Fogle, Thomas Ty

Research on introductory STEM course performance has indicated that student characteristics (age, ethnicity and gender) and Grade Point Average (G.P.A.) can be predictive of student performance, and by implication, a correlation among these factors can help determine course design interventions to help certain types of students perform well in introductory STEM courses. The basis of this study was a community college Visual Basic programming course taught in both online and hybrid format. Beginning students in this course represented a diverse population residing in a large, mid-western, city and surrounding communities. Many of these students were defined as "at-Risk" or "non-traditional, which generally means any combination of socio-economic, cultural, family and employment factors that indicate a student is non-traditional. Research has shown these students struggle academically in technologically dense STEM courses, and may require student services and support to achieve their individual performance goals. The overall number in the study range was 392 distance students and 287 blended course students. The main question of this research was to determine to what extent student characteristics in a community college context, and previous success, as measured in overall G.P.A., were related to course performance in an introductory Visual Basic programming (STEM) course; and, whether or not a combination of these factors and course modality was predictive of success. The study employed a quantitative, quasi-experimental design to assess whether students' course performance was linked to course modality, student characteristics and overall G.P.A. The results indicated that the only predictor of student performance was overall G.P.A. Despite the research analyzed in Chapter 2, there was no statistically significant relationship to modality, age, ethnicity, or gender to performance in the course. Cognitive load is significant in a computer programming course and it was theorized that would be expanded in an online context. However, the results of the analysis showed that course modality did not affect the chances of students performing well. Internal validity constraints may have contributed to the results, as the course is highly controlled and modularized in both online and hybrid format, and taught by few instructors, all of whom are available for face to face problem solving for both online and hybrid students.

Simulation of spatial and temporal properties of aftershocks by means of the fiber bundle model

NASA Astrophysics Data System (ADS)

Monterrubio-Velasco, Marisol; Zúñiga, F. R.; Márquez-Ramírez, Victor Hugo; Figueroa-Soto, Angel

2017-11-01

The rupture processes of any heterogeneous material constitute a complex physical problem. Earthquake aftershocks show temporal and spatial behaviors which are consequence of the heterogeneous stress distribution and multiple rupturing following the main shock. This process is difficult to model deterministically due to the number of parameters and physical conditions, which are largely unknown. In order to shed light on the minimum requirements for the generation of aftershock clusters, in this study, we perform a simulation of the main features of such a complex process by means of a fiber bundle (FB) type model. The FB model has been widely used to analyze the fracture process in heterogeneous materials. It is a simple but powerful tool that allows modeling the main characteristics of a medium such as the brittle shallow crust of the earth. In this work, we incorporate spatial properties, such as the Coulomb stress change pattern, which help simulate observed characteristics of aftershock sequences. In particular, we introduce a parameter ( P) that controls the probability of spatial distribution of initial loads. Also, we use a "conservation" parameter ( π), which accounts for the load dissipation of the system, and demonstrate its influence on the simulated spatio-temporal patterns. Based on numerical results, we find that P has to be in the range 0.06 < P < 0.30, whilst π needs to be limited by a very narrow range ( 0.60 < π < 0.66) in order to reproduce aftershocks pattern characteristics which resemble those of observed sequences. This means that the system requires a small difference in the spatial distribution of initial stress, and a very particular fraction of load transfer in order to generate realistic aftershocks.

A single gene controls leaf background color in caladium (Araceae) and is tightly linked to genes for leaf main vein color, spotting and rugosity.

PubMed

Cao, Zhe; Sui, Shunzhao; Yang, Qian; Deng, Zhanao

2017-01-01

Modern cultivated caladiums ( Caladium × hortulanum ) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem , which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar 'Miss Muffet' and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem . Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F , but is tightly linked to three loci ( S , V and RLF ) controlling leaf spotting, main vein color, and rugosity in caladium. A linkage map that consists of four loci controlling major caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in caladium and in the Araceae family. The information gained in this study will be very useful for caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world.

A single gene controls leaf background color in caladium (Araceae) and is tightly linked to genes for leaf main vein color, spotting and rugosity

PubMed Central

Cao, Zhe; Sui, Shunzhao; Yang, Qian; Deng, Zhanao

2017-01-01

Modern cultivated caladiums (Caladium×hortulanum) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem, which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar ‘Miss Muffet’ and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem. Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F, but is tightly linked to three loci (S, V and RLF) controlling leaf spotting, main vein color, and rugosity in caladium. A linkage map that consists of four loci controlling major caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in caladium and in the Araceae family. The information gained in this study will be very useful for caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world. PMID:28101369

Towards Full Aircraft Airframe Noise Prediction: Detached Eddy Simulations

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R.; Mineck, Raymond E.

2014-01-01

Results from a computational study on the aeroacoustic characteristics of an 18%-scale, semi-span Gulf-stream aircraft model are presented in this paper. NASA's FUN3D unstructured compressible Navier-Stokes solver was used to perform steady and unsteady simulations of the flow field associated with this high-fidelity aircraft model. Solutions were obtained for free-air at a Mach number of 0.2 with the flap deflected at 39 deg, with the main gear off and on (the two baseline configurations). Initially, the study focused on accurately predicting the prominent noise sources at both flap tips for the baseline configuration with deployed flap only. Building upon the experience gained from this initial effort, subsequent work involved the full landing configuration with both flap and main landing gear deployed. For the unsteady computations, we capitalized on the Detached Eddy Simulation capability of FUN3D to capture the complex time-dependent flow features associated with the flap and main gear. To resolve the noise sources over a broad frequency range, the tailored grid was very dense near the flap inboard and outboard tips and the region surrounding the gear. Extensive comparison of the computed steady and unsteady surface pressures with wind tunnel measurements showed good agreement for the global aerodynamic characteristics and the local flow field at the flap inboard tip. However, the computed pressure coefficients indicated that a zone of separated flow that forms in the vicinity of the outboard tip is larger in extent along the flap span and chord than measurements suggest. Computed farfield acoustic characteristics from a FW-H integral approach that used the simulated pressures on the model solid surface were in excellent agreement with corresponding measurements.

An investigation into the effects of conventional heat treatments on mechanical characteristics of new hot working tool steel

NASA Astrophysics Data System (ADS)

Fares, M. L.; Athmani, M.; Khelfaoui, Y.; Khettache, A.

2012-02-01

The effects of conventional heat treatments, i.e. quenching and tempering, on the mechanical characteristics of non standard hot work tool steel, close to either AISI-H11/H13 are investigated. The major elemental composition differences are in carbon, silicon and vanadium. The objective of the carried heat treatments is to obtain an efficient tool performance in terms of hardness, wear resistance and mechanical strength. Experimental results allow an explanation of the surface properties depending mainly on both chemical composition and optimised preheating parameters. After austenitizing at 1050 °C for 15 min, the as-quenched steel in oil bath exhibited the fully martensitic structure (without bainite) connected to a small fraction of retained austenite and complex carbides mainly of M23C6 type. Twice tempering at 500 °C and 600 °C resulted in initiating the precipitation processes and the secondary hardness effect. As a result, carbide content amounted to 3% while the retained austenite content decreased to 0%. Accordingly, the required mechanical properties in terms of hardness and wear are fulfilled and are adequately favourable in handling both shocks and pressures for the expected tool life. Induced microstructures are revealed using optical and scanning electron microscopes. Phase compositions are assessed by means of X-ray diffraction technique while mechanical characteristics are investigated based on hardness and abrasive wear standard tests.

Effects of Interfacial Fluorination on Performance Enhancement of High-k-Based Charge Trap Flash Memory

NASA Astrophysics Data System (ADS)

Wang, Chenjie; Huo, Zongliang; Liu, Ziyu; Liu, Yu; Cui, Yanxiang; Wang, Yumei; Li, Fanghua; Liu, Ming

2013-07-01

The effects of interfacial fluorination on the metal/Al2O3/HfO2/SiO2/Si (MAHOS) memory structure have been investigated. By comparing MAHOS memories with and without interfacial fluorination, it was identified that the deterioration of the performance and reliability of MAHOS memories is mainly due to the formation of an interfacial layer that generates excess oxygen vacancies at the interface. Interfacial fluorination suppresses the growth of the interfacial layer, which is confirmed by X-ray photoelectron spectroscopy depth profile analysis, increases enhanced program/erase efficiency, and improves data retention characteristics. Moreover, it was observed that fluorination at the SiO-HfO interface achieves a more effective performance enhancement than that at the HfO-AlO interface.

The Pharmacology of Actoprotectors: Practical Application for Improvement of Mental and Physical Performance

PubMed Central

Oliynyk, Sergiy; Oh, Seikwan

2012-01-01

Actoprotectors are preparations that enhance body stability against physical loads without increasing oxygen consumption or heat production. Or, in short, actoprotectors are synthetic adaptogens with a significant capacity to improve physical performance. This paper explores the history of actoprotectors’development, their pharmacological properties, mechanism of action, and practical application to the improvement of mental and physical performance. A brief summary of the clinico-pharmacological characteristics of the main representatives of this class (bemitil and bromantane) is provided. Some other synthesized compounds, and even natural ones such as ginseng, also are regarded as potential actoprotectors, and these are treated herein as well. Actoprotectors, owing to their wide-ranging pharmacological activities, high efficiency and safety, can be applied under either normal or extreme conditions. PMID:24009833

Firefighter's compressed air breathing system pressure vessel development program

NASA Technical Reports Server (NTRS)

Beck, E. J.

1974-01-01

The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

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

Li, Meiyan; Xiao, Benyi; Wang, Xu

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewagemore » sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.« less

Dynamic characteristics of a pump-turbine during hydraulic transients of a model pumped-storage system: 3D CFD simulation

NASA Astrophysics Data System (ADS)

Zhang, X. X.; Cheng, Y. G.; Xia, L. S.; Yang, J. D.

2014-03-01

The runaway process in a model pumped-storage system was simulated for analyzing the dynamic characteristics of a pump-turbine. The simulation was adopted by coupling 1D (One Dimensional) pipeline MOC (Method of Characteristics) equations with a 3D (Three Dimensional) pump-turbine CFD (Computational Fluid Dynamics) model, in which the water hammer wave in the 3D zone was defined by giving a pressure dependent density. We found from the results that the dynamic performances of the pump-turbine do not coincide with the static operating points, especially in the S-shaped characteristics region, where the dynamic trajectories follow ring-shaped curves. Specifically, the transient operating points with the same Q11 and M11 in different moving directions of the dynamic trajectories give different n11. The main reason of this phenomenon is that the transient flow patterns inside the pump-turbine are influenced by the ones in the previous time step, which leads to different flow patterns between the points with the same Q11 and M11 in different moving directions of the dynamic trajectories.

The microspace launcher: first step to the fully air-breathing space launcher

NASA Astrophysics Data System (ADS)

Falempin, F.; Bouchez, M.; Calabro, M.

2009-09-01

A possible application for the high-speed air-breathing propulsion is the fully or partially reusable space launcher. Indeed, by combining the high-speed air-breathing propulsion with a conventional rocket engine (combined cycle or combined propulsion system), it should be possible to improve the average installed specific impulse along the ascent trajectory and then make possible more performing launchers and, hopefully, a fully reusable one. During the last 15 years, a lot of system studies have been performed in France on that subject within the framework of different and consecutive programs. Nevertheless, these studies never clearly demonstrated that a space launcher could take advantage of using a combined propulsion system. During last years, the interest to air-breathing propulsion for space application has been revisited. During this review and taking into account technologies development activities already in progress in Europe, clear priorities have been identified regarding a minimum complementary research and technology program addressing specific needs of space launcher application. It was also clearly identified that there is the need to restart system studies taking advantage of recent progress made regarding knowledge, tools, and technology and focusing on more innovative airframe/propulsion system concepts enabling better trade-off between structural efficiency and propulsion system performance. In that field, a fully axisymmetric configuration has been considered for a microspace launcher (10 kg payload). The vehicle is based on a main stage powered by air-breathing propulsion, combined or not with liquid rocket mode. A "kick stage," powered by a solid rocket engine provides the final acceleration. A preliminary design has been performed for different variants: one using a separated booster and a purely air-breathing main stage, a second one using a booster and a main stage combining air-breathing and rocket mode, a third one without separated booster, the main stage ensuring the initial acceleration in liquid rocket mode and a complementary acceleration phase in rocket mode beyond the air-breathing propulsion system operation. Finally, the liquid rocket engine of this third variant can be replaced by a continuous detonation wave rocket engine. The paper describes the main guidelines for the design of these variants and provides their main characteristics. On this basis, the achievable performance, estimated by trajectory simulation, are detailed.

Dynamics of aircraft antiskid braking systems. [conducted at the Langley aircraft landing loads and traction facility

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Stubbs, S. M.; Dreher, R. C.; Smith, E. G.

1982-01-01

A computer study was performed to assess the accuracy of three brake pressure-torque mathematical models. The investigation utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC-9 series 10 airplane. The investigation indicates that the performance of aircraft antiskid braking systems is strongly influenced by tire characteristics, dynamic response of the antiskid control valve, and pressure-torque response of the brake. The computer study employed an average torque error criterion to assess the accuracy of the models. The results indicate that a variable nonlinear spring with hysteresis memory function models the pressure-torque response of the brake more accurately than currently used models.

Sex differences in HIV effects on visual memory among substance-dependent individuals

PubMed Central

Keutmann, Michael K.; Gonzalez, Raul; Maki, Pauline M.; Rubin, Leah H.; Vassileva, Jasmin; Martin, Eileen M.

2016-01-01

HIV’s effects on episodic memory have not been compared systematically between male and female substance-dependent individuals. We administered the Brief Visuospatial Memory Test–Revised (BVMT–R) to 280 substance-dependent HIV+ and HIV− men and women. Groups were comparable on demographic, substance use, and comorbid characteristics. There were no significant main effects of sex or HIV serostatus on BVMT–R performance, but HIV+ women performed significantly more poorly on delayed recall. This effect was most prominent among cocaine-dependent HIV+ women. Our findings are consistent with recent speculation that memory impairment may be more common among HIV+ women, particularly those with a history of cocaine dependence. PMID:27841082

Aeroelasticity and mechanical stability report, 0.27 Mach scale model of the YAH-64 advanced attack helicopter

NASA Technical Reports Server (NTRS)

Straub, F. K.; Johnston, R. A.

1987-01-01

A 27% dynamically scaled model of the YAH-64 Advanced Attack Helicopter main rotor and hub has been designed and fabricated. The model will be tested in the NASA Langley Research Center V/STOL wind tunnel using the General Rotor Model System (GRMS). This report documents the studies performed to ensure dynamic similarity of the model with its full scale parent. It also contains a preliminary aeroelastic and aeromechanical substantiation for the rotor installation in the wind tunnel. From the limited studies performed no aeroelastic stability or load problems are projected. To alleviate a projected ground resonance problem, a modification of the roll characteristics of the GRMS is recommended.

Modeling of rolling element bearing mechanics

NASA Technical Reports Server (NTRS)

Greenhill, L. M.

1991-01-01

Roller element bearings provide the primary mechanical interface between rotating and nonrotating components in the high performance turbomachinery of the Space Shuttle Main Engine (SSME). Knowledge of bearing behavior under various loading and environmental conditions is essential to predicting and understanding the overall behavior of turbopumps, including rotordynamic stability, critical speeds and bearing life. The objective is to develop mathematical models and computer programs to describe the mechanical behavior of ball and cylinder roller bearings under the loading and environmental conditions encountered in the SSME and future high performance rocket engines. This includes characteristics such as nonlinear load/motion relationships, stiffness and damping, rolling element loads for life prediction, and roller and cage stability.

High-Performance WSe2 Complementary Metal Oxide Semiconductor Technology and Integrated Circuits.

PubMed

Yu, Lili; Zubair, Ahmad; Santos, Elton J G; Zhang, Xu; Lin, Yuxuan; Zhang, Yuhao; Palacios, Tomás

2015-08-12

Because of their extraordinary structural and electrical properties, two-dimensional materials are currently being pursued for applications such as thin-film transistors and integrated circuit. One of the main challenges that still needs to be overcome for these applications is the fabrication of air-stable transistors with industry-compatible complementary metal oxide semiconductor (CMOS) technology. In this work, we experimentally demonstrate a novel high performance air-stable WSe2 CMOS technology with almost ideal voltage transfer characteristic, full logic swing and high noise margin with different supply voltages. More importantly, the inverter shows large voltage gain (∼38) and small static power (picowatts), paving the way for low power electronic system in 2D materials.

Study design and baseline characteristics of participants in the Vitamin D in Vulnerable Adults at the VA (the VIVA Study).

PubMed

Lagari, Violet S; Gómez-Marín, Orlando; Levis, Silvina

2014-09-01

Hypovitaminosis D has been associated with age-related physical decline and an increased risk for falls. The objective of this study is to test whether supplementation with 4000IU of vitamin D(3) (vitD(3)) for 9 months will improve, or slow down the decline of the ability to perform physical tests which have been associated with the preservation of independence in sedentary older men. We describe the study design and the baseline characteristics of the 314 men screened in the VIVA-VA Study (Vitamin D In Vulnerable Adults in the VA), a 2-year, single-site, double-blind, placebo-controlled, randomized clinical trial that enrolled sedentary male veterans ages 65 to 95. The main inclusion criteria are 25-OH vitamin D (25-OHD) levels between 10 and 30 ng/ml, and a Short Performance Physical Battery (SPPB) score ≤ 9. The primary outcome of the study is the SPPB. Subjects were recruited from the Miami Veterans Medical Center clinics. The study recruited 314 male veterans of multiethnic backgrounds. The baseline characteristics observed from the 314 men screened in the VIVA-VA Study are consistent with what is expected in a cohort of elderly sedentary men: low physical performance scores, and low 25OHD levels despite living in South Florida. The results of this study that uses a high dose of vitamin D in a cohort of sedentary older men could provide an evidence-based indication for vitamin D supplementation to improve physical performance in this population. Published by Elsevier Inc.

How Do World-Class Nordic Combined Athletes Differ From Specialized Cross-Country Skiers and Ski Jumpers in Sport-Specific Capacity and Training Characteristics?

PubMed

Sandbakk, Øyvind; Rasdal, Vegard; Bråten, Steinar; Moen, Frode; Ettema, Gertjan

2016-10-01

To compare sport-specific laboratory capacities and the annual training of world-class Nordic combined (NC) athletes with specialized ski jumpers (SJ) and cross-country (XC) skiers. Five world-class athletes from each sports discipline were compared. Ski jump imitations were performed on a 3-dimensional force plate in NC athletes and SJ, whereas XC skiing characteristics were obtained from submaximal and maximal roller ski skating on a treadmill in NC athletes and XC skiers. In addition, anthropometrics and annual training characteristics were determined. NC athletes demonstrated 9% higher body mass and showed 17% lower vertical speed in the ski jump imitation than SJ (all P < .05). NC athletes had 12% lower body mass and showed 10% lower peak treadmill speed and 12% lower body-mass-normalized peak oxygen uptake than XC skiers (all P < .05). NC athletes performed half the number of ski-jumping-specific sessions and outdoor ski jumps compared with SJ. NC athletes performed 31% less endurance training, mainly caused by lower amounts of low- and moderate-intensity training in the classical technique, whereas high-intensity strength and speed training and endurance training in the skating technique did not differ substantially from XC skiers. To simultaneously optimize endurance, explosive, and technical capacities in 2 different disciplines, world-class NC athletes train approximately two-thirds of the XC skier's endurance training volume and perform one-half of the ski-jump-specific training compared with SJ. Still, the various laboratory capacities differed only 10-17% compared with SJ and XC skiers.

Institutional Characteristics of Maine's Colleges and Universities, 2000.

ERIC Educational Resources Information Center

Stowers, Kimberly

This document provides data on the characteristics of each public and private postsecondary institution in the state of Maine. Telephone numbers, Web site addresses, accreditation information, tuition and fees, enrollment and awards data, programs offered, and financial aid information are included for each institution. Part 1 contains data for…

Plasma Modification of Poly Lactic Acid Solutions to Generate High Quality Electrospun PLA Nanofibers.

PubMed

Rezaei, Fatemeh; Nikiforov, Anton; Morent, Rino; De Geyter, Nathalie

2018-02-02

Physical properties of pre-electrospinning polymer solutions play a key role in electrospinning as they strongly determine the morphology of the obtained electrospun nanofibers. In this work, an atmospheric-pressure argon plasma directly submerged in the liquid-phase was used to modify the physical properties of poly lactic acid (PLA) spinning solutions in an effort to improve their electrospinnability. The electrical characteristics of the plasma were investigated by two methods; V-I waveforms and Q-V Lissajous plots while the optical emission characteristics of the plasma were also determined using optical emission spectroscopy (OES). To perform a complete physical characterization of the plasma-modified polymer solutions, measurements of viscosity, surface tension, and electrical conductivity were performed for various PLA concentrations, plasma exposure times, gas flow rates, and applied voltages. Moreover, a fast intensified charge-couple device (ICCD) camera was used to image the bubble dynamics during the plasma treatments. In addition, morphological changes of PLA nanofibers generated from plasma-treated PLA solutions were observed by scanning electron microscopy (SEM). The performed plasma treatments were found to induce significant changes to the main physical properties of the PLA solutions, leading to an enhancement of electrospinnability and an improvement of PLA nanofiber formation.

Evaluating the Relationship between Productivity and Quality in Emergency Departments

PubMed Central

Bastian, Nathaniel D.; Riordan, John P.

2017-01-01

Background In the United States, emergency departments (EDs) are constantly pressured to improve operational efficiency and quality in order to gain financial benefits and maintain a positive reputation. Objectives The first objective is to evaluate how efficiently EDs transform their input resources into quality outputs. The second objective is to investigate the relationship between the efficiency and quality performance of EDs and the factors affecting this relationship. Methods Using two data sources, we develop a data envelopment analysis (DEA) model to evaluate the relative efficiency of EDs. Based on the DEA result, we performed multinomial logistic regression to investigate the relationship between ED efficiency and quality performance. Results The DEA results indicated that the main source of inefficiencies was working hours of technicians. The multinomial logistic regression result indicated that the number of electrocardiograms and X-ray procedures conducted in the ED and the length of stay were significantly associated with the trade-offs between relative efficiency and quality. Structural ED characteristics did not influence the relationship between efficiency and quality. Conclusions Depending on the structural and operational characteristics of EDs, different factors can affect the relationship between efficiency and quality. PMID:29065673

Investigation of acoustic and gas dynamic characteristics of strongly swirled turbulent jets

NASA Astrophysics Data System (ADS)

Krasheninnikov, S. Yu; Maslov, VP; Mironov, AK; Toktaliev, PD

2018-03-01

Generalization of the series of experimental and numerical results for properties and characteristics of swirling jets with high swirling intensity W0>1 is considered. These jets are typically used in gas turbine aviation engines for intensification of mixing process and combustion process stabilization. Flow structures in swirling jets and in the near-field are analyzed. It is shown, that, in the main, the flow structure behind the swirling device can be determined by swirling intensity W 0 and acoustic fluctuations field formed far from the jet boundaries. Experimental measurements and numerical simulation of the noise levels of the highly swirling jet are performed using Ffowcs-Williams-Hawkins analogy. Maximum levels of noise axis are observed at angles of 50°-70° from the jet.

Experimental Research on Creep Characteristics of Nansha Soft Soil

PubMed Central

Luo, Qingzi; Chen, Xiaoping

2014-01-01

A series of tests were performed to investigate the creep characteristics of soil in interactive marine and terrestrial deposit of Pearl River Delta. The secondary consolidation test results show that the influence of consolidation pressure on coefficient of secondary consolidation is conditional, which is decided by the consolidation state. The ratio of coefficient of secondary consolidation and coefficient of compressibility C a/C c is almost a constant, and the value is 0.03. In the shear-box test, the direct sheer creep failure of soil is mainly controlled by shear stress rather than the accumulation of shear strain. The triaxial creep features are closely associated with the drainage conditions, and consolidation can weaken the effect of creep. When the soft soil has triaxial creep damage, the strain rate will increase sharply. PMID:24526925

Experimental research on creep characteristics of Nansha soft soil.

PubMed

Luo, Qingzi; Chen, Xiaoping

2014-01-01

A series of tests were performed to investigate the creep characteristics of soil in interactive marine and terrestrial deposit of Pearl River Delta. The secondary consolidation test results show that the influence of consolidation pressure on coefficient of secondary consolidation is conditional, which is decided by the consolidation state. The ratio of coefficient of secondary consolidation and coefficient of compressibility (Ca/Cc) is almost a constant, and the value is 0.03. In the shear-box test, the direct sheer creep failure of soil is mainly controlled by shear stress rather than the accumulation of shear strain. The triaxial creep features are closely associated with the drainage conditions, and consolidation can weaken the effect of creep. When the soft soil has triaxial creep damage, the strain rate will increase sharply.

Effects of wind waves on horizontal array performance in shallow-water conditions

NASA Astrophysics Data System (ADS)

Zavol'skii, N. A.; Malekhanov, A. I.; Raevskii, M. A.; Smirnov, A. V.

2017-09-01

We analyze the influence of statistical effects of the propagation of an acoustic signal excited by a tone source in a shallow-water channel with a rough sea surface on the efficiency of a horizontal phased array. As the array characteristics, we consider the angular function of the array response for a given direction to the source and the coefficient of amplification of the signal-to-noise ratio (array gain). Numerical simulation was conducted in to the winter hydrological conditions of the Barents Sea in a wide range of parameters determining the spatial signal coherence. The results show the main physical effects of the influence of wind waves on the array characteristics and make it possible to quantitatively predict the efficiency of a large horizontal array in realistic shallow-water channels.

Room temperature ionic liquids: new GC stationary phases with a novel selectivity for flavor and fragrance analyses.

PubMed

Cagliero, Cecilia; Bicchi, Carlo; Cordero, Chiara; Liberto, Erica; Sgorbini, Barbara; Rubiolo, Patrizia

2012-12-14

Ionic liquids (ILs) are of great interest as moderately polar to polar stationary phases for GC, because their selectivity differs markedly from that of conventionally used phases. In the flavor, fragrance and essential oil fields, analysts often deal with complex mixtures of compounds having similar structural and physical characteristics (e.g., mono- and sesquiterpenoids), therefore requiring an interactive combination between chromatographic and mass spectral data for correct identification. New GC stationary phases with different selectivity must therefore be continually tested. Performance and evolution over time of commercially available IL columns versus those commonly used in these fields are here evaluated, mainly in view of their routine use. Chromatographic and separative properties (efficiency, separation capability, inertness and/or activity) of commercially available IL columns were compared to those of columns coated with 5% phenyl-95% methylpolysiloxane, 14% cyanopropyl-86% polysiloxane, and polyethylene glycol, on different complexity samples, including standard mixtures of volatile suspected allergens and pesticides, and cornmint and vetiver essential oils. The results show that IL columns can successfully be used for a wide range of applications characteristic of these fields, mainly because of their unusual selectivity, in particular when separations based on functional groups are required. Moreover, the latest generation of IL columns (IL61 and IL60) presents chromatographic performance comparable to or only slightly lower than that of the conventional columns routinely used in these fields. Copyright © 2012 Elsevier B.V. All rights reserved.

Carbon deposition model for oxygen-hydrocarbon combustion, volume 1

NASA Technical Reports Server (NTRS)

Hernandez, R.; Ito, J. I.; Niiya, K. Y.

1987-01-01

Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at pressures of 1000 to 1500 psia. No carbon deposition on the chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational consequences of carbon deposition on preburner/gas generator performance. The report is in two volumes, of which this is Volume 1 covering the main body of the report plus Appendixes A through D.

The Australian Medical Schools Assessment Collaboration: benchmarking the preclinical performance of medical students.

PubMed

O'Mara, Deborah A; Canny, Ben J; Rothnie, Imogene P; Wilson, Ian G; Barnard, John; Davies, Llewelyn

2015-02-02

To report the level of participation of medical schools in the Australian Medical Schools Assessment Collaboration (AMSAC); and to measure differences in student performance related to medical school characteristics and implementation methods. Retrospective analysis of data using the Rasch statistical model to correct for missing data and variability in item difficulty. Linear model analysis of variance was used to assess differences in student performance. 6401 preclinical students from 13 medical schools that participated in AMSAC from 2011 to 2013. Rasch estimates of preclinical basic and clinical science knowledge. Representation of Australian medical schools and students in AMSAC more than doubled between 2009 and 2013. In 2013 it included 12 of 19 medical schools and 68% of medical students. Graduate-entry students scored higher than students entering straight from school. Students at large schools scored higher than students at small schools. Although the significance level was high (P < 0.001), the main effect sizes were small (4.5% and 2.3%, respectively). The time allowed per multiple choice question was not significantly associated with student performance. The effect on performance of multiple assessments compared with the test items as part of a single end-of-year examination was negligible. The variables investigated explain only 12% of the total variation in student performance. An increasing number of medical schools are participating in AMSAC to monitor student performance in preclinical sciences against an external benchmark. Medical school characteristics account for only a small part of overall variation in student performance. Student performance was not affected by the different methods of administering test items.

The influence of training characteristics on the effect of aerobic exercise training in patients with chronic heart failure: A meta-regression analysis.

PubMed

Vromen, T; Kraal, J J; Kuiper, J; Spee, R F; Peek, N; Kemps, H M

2016-04-01

Although aerobic exercise training has shown to be an effective treatment for chronic heart failure patients, there has been a debate about the design of training programs and which training characteristics are the strongest determinants of improvement in exercise capacity. Therefore, we performed a meta-regression analysis to determine a ranking of the individual effect of the training characteristics on the improvement in exercise capacity of an aerobic exercise training program in chronic heart failure patients. We focused on four training characteristics; session frequency, session duration, training intensity and program length, and their product; total energy expenditure. A systematic literature search was performed for randomized controlled trials comparing continuous aerobic exercise training with usual care. Seventeen unique articles were included in our analysis. Total energy expenditure appeared the only training characteristic with a significant effect on improvement in exercise capacity. However, the results were strongly dominated by one trial (HF-action trial), accounting for 90% of the total patient population and showing controversial results compared to other studies. A repeated analysis excluding the HF-action trial confirmed that the increase in exercise capacity is primarily determined by total energy expenditure, followed by session frequency, session duration and session intensity. These results suggest that the design of a training program requires high total energy expenditure as a main goal. Increases in training frequency and session duration appear to yield the largest improvement in exercise capacity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Thunderstorm monitoring and lightning warning, operational applications of the Safir system

NASA Technical Reports Server (NTRS)

Richard, Philippe

1991-01-01

During the past years a new range of studies have been opened by the application of electromagnetic localization techniques to the field of thunderstorm remote sensing. VHF localization techniques were used in particular for the analysis of lightning discharges and gave access to time resolved 3-D images of lightning discharges within thunderclouds. Detection and localization techniques developed have been applied to the design of the SAFIR system. This development's main objective was the design of an operational system capable of assessing and warning in real time for lightning hazards and potential thunderstorm hazards. The SAFIR system main detection technique is the long range interferometric localization of thunderstorm electromagnetic activity; the system performs the localization of intracloud and cloud to ground lightning discharges and the analysis of the characteristics of the activity.

Heavy hydrocarbon main injector technology program

NASA Technical Reports Server (NTRS)

Arbit, H. A.; Tuegel, L. M.; Dodd, F. E.

1991-01-01

The Heavy Hydrocarbon Main Injector Program was an analytical, design, and test program to demonstrate an injection concept applicable to an Isolated Combustion Compartment of a full-scale, high pressure, LOX/RP-1 engine. Several injector patterns were tested in a 3.4-in. combustor. Based on these results, features of the most promising injector design were incorporated into a 5.7-in. injector which was then hot-fire tested. In turn, a preliminary design of a 5-compartment 2D combustor was based on this pattern. Also the additional subscale injector testing and analysis was performed with an emphasis on improving analytical techniques and acoustic cavity design methodology. Several of the existing 3.5-in. diameter injectors were hot-fire tested with and without acoustic cavities for spontaneous and dynamic stability characteristics.

Increasing the quality of excavators’ planetary reduction gearboxes on the basis of dimensional analysis and geometrical characteristics of tooth wheels

NASA Astrophysics Data System (ADS)

Drygin, M. Yu; Kuryshkin, N. P.

2018-01-01

The article describes the problem of extending operational electrically driven excavators’ reducing gear boxes which break down nearly every six months. The main reason of the function loss is the breakdown of the bearing assembly of one of the pinions. The authors performed kinematic, dynamic and geometric calculation of gearing to detect the breakdown reasons. The main reason is that alignment condition is not provided in the differential part and in the power return gear. All toothed gear wheels must be manufactured with the positive bias of the generating rack profile, but in fact all pinions and idle gears are manufactured with negative bias. This lead to an intolerable radial clearance in the gearing and skew of the floating master gears.

Valorization of unauthorized sea disposal dredged sediments as a road foundation material.

PubMed

Achour, Raouf; Abriak, Nor-Edine; Zentar, Rachid; Rivard, Patrice; Gregoire, Pascal

2014-08-01

The main objective of this study is to show the ability of fine dredged material (mainly silty material) to be used in road construction project. This paper is divided into three parts. In the first part, the physical, the mineralogical and the mechanical characteristics of the used fine dredged sediments, as well as their chemical composition and environmental impacts are presented. In the second part, the methodology developed to design the road made from dredged fine sediment is developed. The third part of the paper focuses on the presentation of the road construction and the interpretation of analyses made on cores drilled samples from the road and measurements of the deflection of the road. The environmental assessment, based on leaching tests, is also performed at different issues.

[Job satisfaction among the professionals of AceS Baixo Vouga II].

PubMed

Santana, Silvina; Cerdeira, José

2011-12-01

Job satisfaction is a measure of quality of life at work and is related to emotional states. The interest for this theme is increasing and, in the last years, many studies have attempted to demonstrate its relation with professional performance. Primary care professionals are in the first line of the Serviço Nacional de Saúde (SNS). Therefore, it is necessary that they feel satisfaction with their jobs, in order to perform the tasks with the quality required. Several factors seem to have impact in the satisfaction of these professionals, such as payment, promotion, recognition from supervisors and peers, physical conditions at work and available resources, opportunities for personal development, among others. Insatisfaction may lead to absentism and in the limit to job quit. The main objective of this work is to study job satisfaction among the professionals working at the health centers of ACeS Baixo Vouga II, namely, the relationship between job characteristics and job satisfaction and between job characteristics and considering job quit as a serious option. All the professionals working in the four health centers were inquired. Results show that job characteristics are defined by six dimensions: leadership and supervision, task characteristics and autonomy, payment, personal and professional development and promotion, peers and relations inside the organization and work environment. Globally, payment and opportunities for personal and professional development and promotion are perceived at low level by all the professional groups. Results also show that there are differences by gender and professional groups regarding job satisfaction and the will to quit job. Considering the specificity of the tasks performed by these professionals, measures should be taken in order to improve job satisfaction in the Portuguese health centers.

Simulation research on the effect of cooled EGR, supercharging and compression ratio on downsized SI engine knock

NASA Astrophysics Data System (ADS)

Shu, Gequn; Pan, Jiaying; Wei, Haiqiao; Shi, Ning

2013-03-01

Knock in spark-ignition(SI) engines severely limits engine performance and thermal efficiency. The researches on knock of downsized SI engine have mainly focused on structural design, performance optimization and advanced combustion modes, however there is little for simulation study on the effect of cooled exhaust gas recirculation(EGR) combined with downsizing technologies on SI engine performance. On the basis of mean pressure and oscillating pressure during combustion process, the effect of different levels of cooled EGR ratio, supercharging and compression ratio on engine dynamic and knock characteristic is researched with three-dimensional KIVA-3V program coupled with pressure wave equation. The cylinder pressure, combustion temperature, ignition delay timing, combustion duration, maximum mean pressure, and maximum oscillating pressure at different initial conditions are discussed and analyzed to investigate potential approaches to inhibiting engine knock while improving power output. The calculation results of the effect of just cooled EGR on knock characteristic show that appropriate levels of cooled EGR ratio can effectively suppress cylinder high-frequency pressure oscillations without obvious decrease in mean pressure. Analysis of the synergistic effect of cooled EGR, supercharging and compression ratio on knock characteristic indicates that under the condition of high supercharging and compression ratio, several times more cooled EGR ratio than that under the original condition is necessarily utilized to suppress knock occurrence effectively. The proposed method of synergistic effect of cooled EGR and downsizing technologies on knock characteristic, analyzed from the aspects of mean pressure and oscillating pressure, is an effective way to study downsized SI engine knock and provides knock inhibition approaches in practical engineering.

Foraging characteristics of larval bluegill sunfish and larval longear sunfish in the Kanawha River, West Virginia

USGS Publications Warehouse

Rider, S.J.; Margraf, F.J.

1998-01-01

We determined spatial and temporal foraging characteristics of larval bluegill sunfish (Lepomis macrochirus) and longear sunfish (Lepomis megalotis) in the upper Kanawha River, West Virginia during the summer of 1989. Stomach contents were examined among habitat types (i.e., main channel, main-channel border, and shoreline habitats) and depth (surface, middle, and bottom). Diet of larval bluegill sunfish was dominated by Chironomidae, temporally and spatially. Chironomidae dominated larval longear sunfish diet in main channel and main-channel border collections from all three depths. However, along the shoreline, larval longear sunfish diet was dominated by Cladocera.

Characteristics Study of In-Situ Capacitive Sensor for Monitoring Lubrication Oil Debris

PubMed Central

Han, Zhibin; Wang, Yishou; Qing, Xinlin

2017-01-01

As an essential part of engine health monitoring (EHM), online lubrication oil debris monitoring has recently received great attention for the assessment of rotating and reciprocating parts in aero-engines, due to its high integration, low cost and safe characteristics. However, it is be a challenge to find a suitable sensor operating in such a complex environment. We present an unconventional novel approach, in which a cylinder capacitive sensor is designed and integrated with the pipeline of an engine lubrication system, so that the capacitive sensor can effectively detect changes in the lubrication oil condition. In this paper, an attempt to illustrate the performance characteristics of the developed cylinder capacitive sensor is made, through an experiment system that simulates a real scenario of a lubrication oil system. The main aim of the research was to qualitatively describe the relationship between the sensor parameter and the lubrication oil debris. In addition, the effect of the temperature and flow rate of the lubrication oil on capacitance change was performed by several experiments and we figured out a compensation method. The experimental results demonstrated that the cylinder capacitive sensor can potentially be used for lubrication oil debris monitoring of the health condition of an aero-engine. PMID:29292748

Improvement of the environmental and operational characteristics of vehicles through decreasing the motor fuel density.

PubMed

Magaril, Elena

2016-04-01

The environmental and operational characteristics of motor transport, one of the main consumers of motor fuel and source of toxic emissions, soot, and greenhouse gases, are determined to a large extent by the fuel quality which is characterized by many parameters. Fuel density is one of these parameters and it can serve as an indicator of fuel quality. It has been theoretically substantiated that an increased density of motor fuel has a negative impact both on the environmental and operational characteristics of motor transport. The use of fuels with a high density leads to an increase in carbonization within the engine, adversely affecting the vehicle performance and increasing environmental pollution. A program of technological measures targeted at reducing the density of the fuel used was offered. It includes a solution to the problem posed by changes in the refining capacities ratio and the temperature range of gasoline and diesel fuel boiling, by introducing fuel additives and adding butanes to the gasoline. An environmental tax has been developed which allows oil refineries to have a direct impact on the production of fuels with improved environmental performance, taking into account the need to minimize the density of the fuel within a given category of quality.

Hidden Markov Model and Support Vector Machine based decoding of finger movements using Electrocorticography

PubMed Central

Wissel, Tobias; Pfeiffer, Tim; Frysch, Robert; Knight, Robert T.; Chang, Edward F.; Hinrichs, Hermann; Rieger, Jochem W.; Rose, Georg

2013-01-01

Objective Support Vector Machines (SVM) have developed into a gold standard for accurate classification in Brain-Computer-Interfaces (BCI). The choice of the most appropriate classifier for a particular application depends on several characteristics in addition to decoding accuracy. Here we investigate the implementation of Hidden Markov Models (HMM)for online BCIs and discuss strategies to improve their performance. Approach We compare the SVM, serving as a reference, and HMMs for classifying discrete finger movements obtained from the Electrocorticograms of four subjects doing a finger tapping experiment. The classifier decisions are based on a subset of low-frequency time domain and high gamma oscillation features. Main results We show that decoding optimization between the two approaches is due to the way features are extracted and selected and less dependent on the classifier. An additional gain in HMM performance of up to 6% was obtained by introducing model constraints. Comparable accuracies of up to 90% were achieved with both SVM and HMM with the high gamma cortical response providing the most important decoding information for both techniques. Significance We discuss technical HMM characteristics and adaptations in the context of the presented data as well as for general BCI applications. Our findings suggest that HMMs and their characteristics are promising for efficient online brain-computer interfaces. PMID:24045504

Performance characteristics according to the radial position of gas distributor holes in a low-power cylindrical Hall thruster

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

Gao, Yuanyuan; Liu, Hui; Hu, Peng

The effect of radial position of gas holes in the distributor on the performance of cylindrical Hall thruster was investigated. A series of gas distributors with different radial positions (R{sub g}) of holes were designed in the experiment. The results show that the larger R{sub g} leads to the higher ion current and electron current; meanwhile, the beam angle in plume is narrowed. Nevertheless, the peak energy in ion energy distribution function increases, together with the narrowing of ion energy distribution function. As a result, the overall performance is enhanced. It is suggested that the growing of R{sub g} couldmore » lead to the movement of the main ionization region towards anode, which could promote ion velocity and the clearer separation of acceleration region from ionization region. This work can provide some optimal design ideas to improve the performance of the thruster.« less

Effects of working gas pressure on zirconium dioxide thin film prepared by pulsed plasma deposition: roughness, wettability, friction and wear characteristics.

PubMed

Berni, M; Marchiori, G; Gambardella, A; Boi, M; Bianchi, M; Russo, A; Visani, A; Marcacci, M; Pavan, P G; Lopomo, N F

2017-08-01

In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100m a reduction rate of about 7% in dry, 12% in NaCl and 5% in presence of serum was obtained compared to the uncoated counterpart. Differently from what highlighted for friction, no correlation was found between wear rate and morphological parameters. These findings, in agreement with literature, underlined the effect of the deposition pressure on the morphological properties, but suggested that physical characteristics are influenced too. Further research on the deposition process will be required in order to improve the tribological performance of the coating at long distances, addressing - above all - orthopedic applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

2016-01-01

As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. For the thrust chamber assembly of the test article, several configurations of new main injectors, using relatively conventional gas-centered swirl coaxial injector elements, were designed and fabricated. The design and fabrication of these main injectors are described in a companion paper at this JANNAF meeting. New ablative combustion chambers were fabricated based on hardware previously used at NASA for testing at similar size and pressure. An existing oxygen/RP-1 oxidizer-rich subscale preburner injector from a previous NASA-funded program, along with existing and new inter-connecting hot gas duct hardware, were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. Results from independent hot-fire tests of the preburner injector in a combustion chamber with a sonic throat are described in companion papers at this JANNAF conference. The resulting integrated test article - which includes the preburner, inter-connecting hot gas duct, main injector, and ablative combustion chamber - was assembled at Test Stand 116 at the East Test Area of the NASA Marshall Space Flight Center. The test article was well instrumented with static and dynamic pressure, temperature, and acceleration sensors to allow the collected data to be used for combustion analysis model development. Hot-fire testing was conducted with main combustion chamber pressures ranging from 1400 to 2100 psia, and main combustion chamber mixture ratios ranging from 2.4 to 2.9. Different levels of fuel film cooling injected from the injector face were examined ranging from none to about 12% of the total fuel flow. This paper presents the hot-fire test results of the integrated test article. Combustion performance, stability, thermal, and compatibility characteristics of both the preburner and the thrust chamber are described. Another companion paper at this JANNAF meeting includes additional and more detailed test data regarding the combustion dynamics and stability characteristics.

[Clinical characteristics and management of children hospitalized for influenza in four epidemic seasons (2002-2006)].

PubMed

Ros Aranal, I; Navarra Vicente, B; Lavilla Fernández, M J; De Juan Martín, F; Bouthelier Moreno, M; Omeñaca Teres, M; Ciria Calavia, L

2008-01-01

Influenza is frequent during childhood, affecting approximately 30-40 % of children. To identify the most frequent causes of hospitalization in children admitted to hospital for influenza, as well as the main symptoms and clinical diagnoses at discharge, and to relate these factors with the type of influenza virus and patients' age. A further aim was to evaluate the use of the diagnostic and therapeutic methods. We performed a retrospective descriptive study through a review of the medical records of children admitted to the Miguel Servet Children's Hospital in Zaragoza (Spain) for influenza in four epidemic seasons (2002-2006). A total of 178 influenza cases were found, 132 due to influenza A and 46 due to influenza B. Hospital admission was mainly due to fever without focus, especially in infants aged less than 6 months, followed by convulsions and shortness of breath. The main symptoms were fever, cough, rhinitis, and vomiting. The latter was especially frequent in children older than 3 years and in patients with influenza B virus. The main discharge diagnoses were upper respiratory tract infection, pharyngitis-tonsillitis, and otitis. Diagnosis of bronchitis was more frequent in children aged less than 2 years old. Chest X-ray was performed in 80% of the patients and lung consolidation was found in 10.5%. Antibiotic therapy was administered in 59% of the patients, mainly amoxicillin-clavulanic acid. The causes of admission for influenza and clinical presentation of this infection vary widely, sometimes depending on age and the type of influenza virus.

YADBrowser: A Browser for Web-Based Educational Applications

ERIC Educational Resources Information Center

Zaldivar, Vicente Arturo Romero; Arandia, Jon Ander Elorriaga; Brito, Mateo Lezcano

2005-01-01

In this article, the main characteristics of the educational browser YADBrowser are described. One of the main objectives of this project is to define new languages and object models which facilitate the creation of educational applications for the Internet. The fundamental characteristics of the object model of the browser are also described.…

Thermo-Hydraulic Characteristics of Anatase Titania Nanofluids Flowing Through a Circular Conduit.

PubMed

Kristiawan, Budi; Kamal, Samsul; Yanuar

2016-06-01

The thermo-hydraulic characteristics of anatase titanium dioxide dispersed into distilled water with particle concentration of 0.1, 0.3, and 0.5 vol.% were investigated experimentally in this work. The influence of rheological behavior on hydrodynamic and convective heat transfer characteristics was evaluated under both laminar and turbulent flow conditions in a plain conduit and with twisted tape insert for twist ratio of 7. The nanofluids exhibited a strong shear-thinning behavior at low shear rate particularly higher particle concentration. The non-Newtonian titania nanofluids have also demonstrated a drag reduction phenomena in turbulent flow. At equal Reynolds number, the values of performance evaluation criterion in a conduit inserted a twisted tape were lower than those of in a plain conduit. It implies the unfavourable energy budget for twisted tape insert. The convective heat transfer coefficient does not gradually enhance with an increase of particle concentration. The flow features due mainly to the rheology of colloidal dispersions might be a reason for this phenomenon.

Socio-demographic, Behavioral and Health Characteristics of Underage Female Sex Workers in Mozambique: The Need to Protect a Generation from HIV Risk.

PubMed

Inguane, Celso; Horth, Roberta Z; Miranda, Angélica E; Young, Peter W; Sathane, Isabel; Cummings, Beverley E; Augusto, Ângelo; Raymond, Henry F; Mcfarland, Willi

2015-12-01

Characteristics, HIV risk, and program coverage for underage female sex workers (FSW) are rarely systematically described worldwide. We compared characteristics of underage (15-17 years old) and adult (≥18 years old) FSW in three main urban areas of Mozambique (Maputo, Beira and Nampula) using data from three respondent-driven sampling surveys implemented in 2011-2012. Among survey participants, 9.8 % (39/400) in Maputo, 17.0 % (70/411) in Beira and 25.6 % (110/429) in Nampula were underage. Over half reported performing sex work to afford daily living, and 29.7-50.0 % had unprotected sex with their last client. The proportion of underage FSW having accessed care and prevention services was lower compared to adult FSW. While HIV prevalence among underage FSW was lower than in adults, it increased markedly with age. Our results point to the urgency of expanding prevention and care programs geared towards underage FSW.

Socio-demographic, Behavioral and Health Characteristics of Underage Female Sex Workers in Mozambique: The Need to Protect a Generation from HIV Risk

PubMed Central

Horth, Roberta Z.; Miranda, Angélica E.; Young, Peter W.; Sathane, Isabel; Cummings, Beverley E.; Augusto, Ângelo; Raymond, Henry F.; Mcfarland, Willi

2016-01-01

Characteristics, HIV risk, and program coverage for underage female sex workers (FSW) are rarely systematically described worldwide. We compared characteristics of underage (15–17 years old) and adult (≥18 years old) FSW in three main urban areas of Mozambique (Maputo, Beira and Nampula) using data from three respondent-driven sampling surveys implemented in 2011–2012. Among survey participants, 9.8 % (39/400) in Maputo, 17.0 % (70/411) in Beira and 25.6 % (110/429) in Nampula were underage. Over half reported performing sex work to afford daily living, and 29.7–50.0 % had unprotected sex with their last client. The proportion of underage FSW having accessed care and prevention services was lower compared to adult FSW. While HIV prevalence among underage FSW was lower than in adults, it increased markedly with age. Our results point to the urgency of expanding prevention and care programs geared towards underage FSW. PMID:25931241

The effect of lizardite surface characteristics on pyrite flotation

NASA Astrophysics Data System (ADS)

Feng, Bo; Feng, Qiming; Lu, Yiping

2012-10-01

The effect of lizardite surface characteristics on pyrite flotation has been investigated through flotation tests, adsorption tests, zeta potential measurements, FTIR study, X-ray photoelectron spectroscopy (XPS) and sedimentation tests. The flotation results show that at pH value 9, where flotation of nickel sulfide ores is routinely performed, two kinds of lizardite samples (native lizardite and leached lizardite) have different effects on the flotation of pyrite. The native lizardite adheres to the surface of pyrite and reduces pyrite flotation recovery while the leached lizardite does not interfere with pyrite flotation. Infrared analyses and XPS tests illustrate that acid leaching changed the surface characteristics of lizardite mineral and the leached lizardite has less magnesium on its surface. It has been determined that the electro-kinetic behavior of lizardite aqueous suspensions is mainly a function of the Mg/Si atomic ratio on lizardite surface. So, the low isoelectric point observed in the leached sample has been linked to values of this ratio lower than that of the native lizardite.

Clinical epidemiology of eosinophilic pustular folliculitis: results from a nationwide survey in Japan.

PubMed

Yamamoto, Yosuke; Nomura, Takashi; Kabashima, Kenji; Miyachi, Yoshiki

2015-01-01

No epidemiological study has examined the clinical characteristics, including medication use, of patients with eosinophilic pustular folliculitis (EPF). To describe the clinical characteristics for EPF and to examine the factors associated with the effectiveness of oral indomethacin for EPF. A cross-sectional study was performed of patients with EPF who visited the dermatology departments of the 67 main teaching facilities in Japan. We documented the patient characteristics and examined factors associated with the effectiveness of oral indomethacin. A total of 145 patients with EPF were enrolled; 62.8% were prescribed oral indomethacin. A multivariable analysis revealed that female patients were more likely to exhibit complete response to oral indomethacin after adjustment for confounders (adjusted proportion ratio = 1.93, p = 0.04). Oral indomethacin has been accepted as a first-line treatment in EPF. Our results suggest that there is a sex difference in the treatment response to oral indomethacin. © 2014 S. Karger AG, Basel.

On the dispersion characteristics of metamaterial transmission lines

NASA Astrophysics Data System (ADS)

Sisó, G.; Gil, M.; Bonache, J.; Martín, F.

2007-10-01

In this paper, a detailed analysis of the dispersion characteristics of metamaterial transmission lines, based on the lumped element T-circuit model is carried out. One of the main relevant characteristics of these artificial lines is the possibility to tailor the phase response. This leads to unique properties which are of interest for microwave circuit design, such as bandwidth enhancement or multiband (dual-band) operation, among others. However, it is shown in this paper that, in spite of the larger number of circuit parameters (as compared to conventional lines), there exist intrinsic limitations that may limit the performance of such metamaterial transmission lines under certain conditions. In this paper these limitations are pointed out from an accurate analysis of the phase response and the Foster's reactance theorem [Bell Syst. Tech. 3, 259 (1924)]. From the results of this paper, important guidelines for the design of microwave components based on metamaterial transmission lines are inferred. The fabrication and characterization of different metamaterial transmission lines will corroborate the theoretical results.

The Physical Layer Security Experiments of Cooperative Communication System with Different Relay Behaviors.

PubMed

Su, Yishan; Han, Guangyao; Fu, Xiaomei; Xu, Naishen; Jin, Zhigang

2017-04-06

Physical layer security is an attractive security mechanism, which exploits the randomness characteristics of wireless transmission channel to achieve security. However, it is hampered by the limitation of the channel condition that the main channel must be better than the eavesdropper channel. To alleviate the limitation, cooperative communication is introduced. Few studies have investigated the physical layer security of the relay transmission model. In this paper, we performed some experiments to evaluate the physical layer security of a cooperative communication system, with a relay operating in decode-and-forward (DF) cooperative mode, selfish and malicious behavior in real non-ideal transmission environment. Security performance is evaluated in terms of the probability of non-zero secrecy capacity. Experiments showed some different results compared to theoretical simulation: (1) to achieve the maximum secrecy capacity, the optimal relay power according to the experiments result is larger than that of ideal theoretical results under both cooperative and selfish behavior relay; (2) the relay in malicious behavior who forwards noise to deteriorate the main channel may deteriorate the eavesdropper channel more seriously than the main channel; (3) the optimal relay positions under cooperative and selfish behavior relay cases are both located near the destination because of non-ideal transmission.

Integrated biomass pyrolysis with organic Rankine cycle for power generation

NASA Astrophysics Data System (ADS)

Nur, T. B.; Syahputra, A. W.

2018-02-01

The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used to generate power from waste heat available in industrial processes. Biomass pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. In the application, biomass pyrolysis can be divided into three main categories; slow, fast and flash pyrolysis mainly aiming at maximizing the products of bio-oil or biochar. The temperature of synthesis gas generated during processes can be used for Organic Rankine Cycle to generate power. The heat from synthesis gas during pyrolysis processes was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. In this study, the potential of the palm oil empty fruit bunch, palm oil shell, and tree bark have been used as fuel from biomass to generate electricity by integrated with ORC. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC system. Through Aspen Plus, this study analyses the influences on performance of main thermodynamic parameters, showing the possibilities of reaching an optimum performance for different working conditions that are characteristics of different design parameters.

Rehearsal dynamics in elementary school children.

PubMed

Lehmann, Martin; Hasselhorn, Marcus

2012-03-01

Several studies on free recall suggest that processes responsible for recall are analogous to processes responsible for rehearsal. In children, the relationship between cumulative rehearsal and recall performance has been proven to be critical; however, the locus of the effect of rehearsal is not yet fully understood. To unfold the mechanisms that come into play in an overt rehearsal free recall task, we assessed rehearsal and recall sequences in children between 8 and 10 years of age. These sequences give information about the context in which items are repeated and rearranged throughout the list and subsequently recalled. Rehearsal sequences consisted mainly of items from neighboring list positions in their original temporal order. The same characteristics were true for recall sequences. Qualitatively, order effects during study and recall did not differ over age groups. However, in older children who were using cumulative rehearsal more intensively, successive rehearsal and recall of items in their original order was more pronounced. Therefore, we suggest that a main feature of item rehearsal with regard to facilitating recall is the strengthening of interitem associations based on the temporal order within a list and that this characteristic develops with age. Copyright © 2011 Elsevier Inc. All rights reserved.

Match running performance and skill execution improves with age but not the number of disposals in young Australian footballers.

PubMed

Gastin, Paul B; Tangalos, Christie; Torres, Lorena; Robertson, Sam

2017-12-01

This study investigated age-related differences in maturity, physical and functional characteristics and playing performance in youth Australian Football (AF). Young male players (n = 156) were recruited from 12 teams across 6 age groups (U10-U15) of a recreational AF club. All players were tested for body size, maturity and fitness. Player performance was assessed during a match in which disposals (kicks and handballs) and their effectiveness were coded from a video recording and match running performance measured using Global Positioning System. Significant main effects (P < 0.01) for age group were observed for age, years to peak height velocity, body mass, height, 20 m sprint, maximal speed over 20 m, vertical jump, 20 m multistage shuttle run, match distance, high-speed running distance, peak speed, number of effective disposals and percentage of effective disposals. Age-related differences in fitness characteristics (speed, lower body power and endurance) appeared to transfer to match running performance. The frequency in which players disposed of the football did not differ between age groups, however the effectiveness of each disposal (i.e., % effective disposals) improved with age. Match statistics, particularly those that evaluate skill execution outcome (i.e., effectiveness), are useful to assess performance and to track player development over time. Differences between age groups, and probably variability within age groups, are strongly associated with chronological age and maturity.

Rambutan-like CNT-Al2O3 scaffolds for high-performance cathode catalyst layers of polymer electrolyte fuel cells

NASA Astrophysics Data System (ADS)

Chang, KwangHyun; Cho, Seonghun; Lim, Eun Ja; Park, Seok-Hee; Yim, Sung-Dae

2018-03-01

Rambutan-like CNT-Al2O3 scaffolds are introduced as a potential candidate for CNT-based catalyst supports to overcome the CNT issues, such as the easy bundling in catalyst ink and the poor pore structure of the CNT-based catalyst layers, and to achieve high MEA performance in PEFCs. Non-porous α-phase Al2O3 balls are introduced to enable the growth of multiwalled CNTs, and Pt nanoparticles are loaded onto the CNT surfaces. In a half-cell, the Pt/CNT-Al2O3 catalyst shows much higher durability than those of a commercial Pt/C catalyst even though it shows lower oxygen reduction reaction (ORR) activity than Pt/C. After using the decal process for MEA formation, the Pt/CNT-Al2O3 shows comparable initial performance characteristics to Pt/C, overcoming the lower ORR activity, mainly due to the facile oxygen transport in the cathode catalyst layers fabricated with the CNT-Al2O3 scaffolds. The Pt/CNT-Al2O3 also exhibits much higher durability against carbon corrosion than Pt/C owing to the durable characteristics of CNTs. Systematic analysis of single cell performance for both initial and after degradation is provided to understand the origin of the high initial performance and durable behavior of Pt/CNT-Al2O3-based catalyst layers. This will provide insights into the design of electrocatalysts for high-performance MEAs in PEFCs.

Characteristics of breast cancer in Central China, literature review and comparison with USA.

PubMed

Chen, Chuang; Sun, Si; Yuan, Jing-Ping; Wang, Yao-Huai; Cao, Tian-Ze; Zheng, Hong-Mei; Jiang, Xue-Qing; Gong, Yi-Ping; Tu, Yi; Yao, Feng; Hu, Ming-Bai; Li, Juan-Juan; Sun, Sheng-Rong; Wei, Wen

2016-12-01

This work was to analyze characteristics of breast cancer (BC) in Central China, summarize main characteristics in China and compare with USA. BC main characteristics from four hospitals in Central China from 2002 to 2012 were collected and analyzed. All the single and large-scale clinical reports covering at least ten years were selected and summarized to calculate the BC characteristics of China. BC Characteristics in USA were selected based on the database from Surveillance, Epidemiology, and End Results (SEER) Program. Age distribution in Central China was normal with one age peak at 45-49 years, displaying differences from USA and Chinese American with two age peaks. BC characteristics in Central China displayed distinct features from USA and Chinese American, including significant younger onset age, lower proportion of patients with stage I, lymph node negative, small tumor size and ER positive. A total ten long-term and large-scale clinical reports were selected for BC characteristics of Mainland China analysis. A total of 53,571 BC patients were enrolled from 1995 to 2012. The main characteristics of BC in Mainland China were similar as that in Central China, but were significant different from developed regions of China (Hong Kong and Taiwan), USA and Chinese American. BC characteristics in Central China displayed representative patterns of Mainland China, while showed distinct patterns from Chinese patients in other developed areas and USA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mission Applicability and Benefits of Thin-Film Integrated Power Generation and Energy Storage

NASA Technical Reports Server (NTRS)

Hoffman, David; Raffaelle, Ryne P.; Landis, Geoffrey A.; Hepp, Aloysius F.

2001-01-01

This paper discusses the space mission applicability and benefits of a thin-film integrated power generation and energy storage device, i.e., an "Integrated Power Source" or IPS. The characteristics of an IPS that combines thin-film photo-voltaic power generation with thin-film energy storage are described. Mission concepts for a thin-film IPS as a spacecraft main electrical power system, as a decentralized or distributed power source and as an uninterruptible power supply are discussed. For two specific missions, preliminary sizing of an IPS as a main power system is performed and benefits are assessed. IPS developmental challenges that need to be overcome in order to realize the benefits of an IPS are examined. Based on this preliminary assessment, it is concluded that the most likely and beneficial application of an IPS will be as the main power system on a very small "nanosatellite," or in specialized applications serving as a decentralized or distributed power source or uninterruptible power supply.

Toxin-Induced Models of Parkinson's Disease

PubMed Central

Bové, Jordi; Prou, Delphine; Perier, Céline; Przedborski, Serge

2005-01-01

Summary: Parkinson's disease (PD) is a common neurodegenerative disease that appears essentially as a sporadic condition. It results mainly from the death of dopaminergic neurons in the substantia nigra. PD etiology remains mysterious, whereas its pathogenesis begins to be understood as a multifactorial cascade of deleterious factors. Most insights into PD pathogenesis come from investigations performed in experimental models of PD, especially those produced by neurotoxins. Although a host of natural and synthetic molecules do exert deleterious effects on dopaminergic neurons, only a handful are used in living laboratory animals to recapitulate some of the hallmarks of PD. In this review, we discuss what we believe are the four most popular parkinsonian neurotoxins, namely 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, and paraquat. The main goal is to provide an updated summary of the main characteristics of each of these four neurotoxins. However, we also try to provide the reader with an idea about the various strengths and the weaknesses of these neurotoxic models. PMID:16389312

Carbon Deposition Model for Oxygen-Hydrocarbon Combustion, Volume 2

NASA Technical Reports Server (NTRS)

Hernandez, R.; Ito, J. I.; Niiya, K. Y.

1987-01-01

Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at chamber pressures of 1000 to 1500 psia. No carbon deposition on chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational concequences of carbon deposition on preburner/gas generator performance. This is Volume 2 of the report, which contains data plots of all the test programs.

Mission Applicability and Benefits of Thin-Film Integrated Power Generation and Energy Storage

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Raffaelle, Ryne P.; Landis, Geoffrey A.; Hepp, Aloysius F.

2001-01-01

This paper discusses the space mission applicability and benefits of a thin-film integrated power generation and energy storage device, i.e., an "Integrated Power Source" or IPS. The characteristics of an IPS that combines thin-film photovoltaic power generation with thin-film energy storage are described. Mission concepts for a thin-film IPS as a spacecraft main electrical power system, as a decentralized or distributed power source and as an uninterruptible power supply are discussed. For two specific missions, preliminary sizing of an IPS as a main power system is performed and benefits are assessed. IPS developmental challenges that need to be overcome in order to realize the benefits of an IPS are examined. Based on this preliminary assessment, it is concluded that the most likely and beneficial application of an IPS will be as the main power system on a very small "nanosatellite," or in specialized applications serving as a decentralized or distributed power source or uninterruptible power supply.

[Effect of hydrochemistry characteristics under impact of human activity: a case study in the upper reaches of the Xijiang River basin].

PubMed

Yu, Shil; Sun, Ping-an; Du, Wen-yue; He, Shi-yi; Li, Rui

2015-01-01

In this paper, observation and sampling were taken three times a month in a hydrological year for three typical sections of the middle and upper reaches of the Xijiang River basin, based on the data of hydrochemistry and flow, the article mainly discusses the evolution process of hydrochemistry in river under natural process and impact of human activity. Hydrochemical characteristics of 116. samples were analyzed in the study area. The hydrochemistry type in the middle and upper reaches of the Xijiang River basin belonged to HCO3- -Ca2+ type, and the chemical weathering type mainly came from carbonate rock weathering. Ca2+ and HCO3- were the main cations and anions, which reflected that hydrochemical characteristics of river in karst area mainly affected by the dissolution of carbonate rock. Na, Mg2, Ca2+ and Cl- mainly affected by natural conditions, the impact of human activity was little. K+, NO3-, SO4(2-) and HCO3- were affected by human activity in different degrees, and it showed different influence ways. This study had an important significance for the change of river hydrochemistry, water quality characteristics, and the effect on substance transported fluxes in the downstream of Pearl River and water quality protection in South China Monsoon Area.

Transient Characteristics of Free Piston Vuilleurnier Cycle Heat Pumps

NASA Astrophysics Data System (ADS)

Matsue, Junji; Fujimoto, Norioki; Shirai, Hiroyuki

A dynamic analysis of a free piston Vuilleumier cycle heat pump was performed using a time-stepping integration method to investigate transient characteristics under power controlling. The nonlinear relationship between displacement and force for pistons was taken into account for the motion of reciprocating components. The force for pistons is mainly caused by the pressure change of working gas varying with piston displacements; moreover nonlinear viscous dissipative force due to the oscillating flow of working gas in heat exchangers and discontinuous damping force caused by solid friction at piston seals and rod seals are included. The displacements of pistons and pressure changes in the Vuilleumier cycle heat pump were integrated by an ideal isothermal thermodynamic relationship. It was assumed that the flow friction was proportional to the kinematic pressure of working gas, and that the solid friction at the seals was due to the functions of the working gas pressure and the tension of seal springs. In order to investigate the transient characteristics of a proposed free piston Vuilleumier cycle heat pump machine when hot-side working gas temperatures and alternate force were changed, some calculations were performed and discussed. These calculation results make clear transient characteristics at starting and power controlling. It was further found that only a small amount of starter power is required in particular conditions. During controlling, the machine becomes unstable when there is ar elatively large reduction in cooling or heating power. Therefore, an auxiliary device is additionally needed to obtain stable operation, such as al inear motor.

Management of oil spill contamination in the Gulf of Patras caused by an accidental subsea blowout.

PubMed

Makatounis, Panagiotis Eleftherios; Skancke, Jørgen; Florou, Evanthia; Stamou, Anastasios; Brandvik, Per Johan

2017-12-01

A methodology is presented and applied to assess the oil contamination probability in the Gulf of Patras and the environmental impacts on the environmentally sensitive area of Mesolongi - Aitoliko coastal lagoons, and to examine the effectiveness of response systems. The procedure consists of the following steps: (1) Determination of the computational domain and the main areas of interest, (2) determination of the drilling sites and oil release characteristics, (3) selection of the simulation periods and collection of environmental data, (4) identification of the species of interest and their characteristics, (5) performance of stochastic calculations and oil contamination probability analysis, (6) determination of the worst-cases, (7) determination of the characteristics of response systems, (8) performance of deterministic calculations, and (9) assessment of the impact of oil spill in the areas of interest. Stochastic calculations that were performed for three typical seasonal weather variations of the year 2015, three oil release sites and specific oil characteristics, showed that there is a considerable probability of oil pollution that reaches 30% in the Mesolongi - Aitoliko lagoons. Based on a simplified approach regarding the characteristic of the sensitive birds and fish in the lagoons, deterministic calculations showed that 78-90% of the bird population and 2-4% of the fish population are expected to be contaminated in the case of an oil spill without any intervention. The use of dispersants reduced the amount of stranded oil by approximately 16-21% and the contaminated bird population of the lagoons to approximately 70%; however, the affected fish population increased to 6-8.5% due to the higher oil concentration in the water column. Mechanical recovery with skimmers "cleaned" almost 10% of the released oil quantity, but it did not have any noticeable effect on the stranded oil and the impacted bird and fish populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Nutritional impact of inflammatory bowel diseases on children and adolescents].

PubMed

dos Santos, Gilton Marques; Silva, Luciana Rodrigues; Santana, Genoile Oliveira

2014-12-01

To perform a systematic review of the literature about the nutritional impact of inflammatory bowel diseases in children and adolescents. A systematic review was performed using PubMed/MEDLINE, LILACS and SciELo databases, with inclusion of articles in Portuguese and in English with original data, that analyzed nutritional aspects of inflammatory bowel diseases in children and adolescents. The initial search used the terms "inflammatory bowel diseases" and "children" or "adolescents" and "nutritional evaluation" or "nutrition deficiency". The selection of studies was initially performed by reading the titles and abstracts. Review studies and those without data for pediatric patients were excluded. Subsequently, the full reading of the articles considered relevant was performed. 237 studies were identified, and 12 of them were selected according to the inclusion criteria. None of them was performed in South America. During the analysis of the studies, it was observed that nutritional characteristics of patients with inflammatory bowel disease may be altered; the main reports were related to malnutrition, growth stunting, delayed puberty and vitamin D deficiency. There are nutritional consequences of inflammatory bowel diseases in children and adolescents, mainly growth stunting, slower pubertal development, underweight and vitamin deficiencies. Nutritional impairments were more significant in patients with Crohn's disease; overweight and obesity were more common in patients with ulcerative rectocolitis. A detailed nutritional assessment should be performed periodically in children and adolescents with inflammatory bowel disease. Copyright © 2014 Associação de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

Limno-reservoirs as a new landscape, environmental and touristic resource: Pareja Limno-reservoir as a case of study (Guadalajara, Spain)

NASA Astrophysics Data System (ADS)

Díaz-Carrión, I.; Sastre-Merlín, A.; Martínez-Pérez, S.; Molina-Navarro, E.; Bienes-Allas, R.

2012-04-01

A limno-reservoir is a hydrologic infrastructure with the main goal of generating a body of water with a constant level in the riverine zone of a reservoir, building a dam that makes de limno-reservoir independent from the main body of water. This dam can be built in the main river supplying the reservoir or any tributary as well flowing into it. Despite its novel conception and design, around a dozen are already operative in some Spanish reservoirs. This infrastructure allows the new water body to be independent of the main reservoir management, so the water level stability is its main distinctive characteristic. It leads to the development of environmental, sports and cultural initiatives; which may be included in a touristic exploitation in a wide sense. An opinion poll was designed in 2009 to be carried out the Pareja Limno-reservoir (Entrepeñas reservoir area, Tajo River Basin, central Spain). The results showed that for both, Pareja inhabitants and occasional visitors, the limno-reservoir has become an important touristic resource, mainly demanded during summer season. The performance of leisure activities (especially swimming) are being the main brand of this novel hydraulic and environmental infrastructure, playing a role as corrective and/or compensatory action which is needed to apply in order to mitigate the environmental impacts of the large hydraulic constructions.

SSME alternate turbopump (pump section) axial load analysis

NASA Technical Reports Server (NTRS)

Crease, G. A.; Rosello, A., Jr.; Fetfatsidis, A. K.

1989-01-01

A flow balancing computer program constructed to calculate the axial loads on the Space Shuttle Main Engine (SSME) alternate turbopumps (ATs) pump sections are described. The loads are used in turn to determine load balancing piston design requirements. The application of the program to the inlet section, inducer/impeller/stage, bearings, seals, labyrinth, damper, piston, face and corner, and stationary/rotating surfaces is indicated. Design analysis results are reported which show that the balancing piston's designs are adequate and that performance and life will not be degraded by the turbopump's axial load characteristics.

The Multi-Player Performance-Enhancing Drug Game

PubMed Central

Haugen, Kjetil K.; Nepusz, Tamás; Petróczi, Andrea

2013-01-01

This paper extends classical work on economics of doping into a multi-player game setting. Apart from being among the first papers formally formulating and analysing a multi-player doping situation, we find interesting results related to different types of Nash-equilibria (NE). Based mainly on analytic results, we claim at least two different NE structures linked to the choice of prize functions. Linear prize functions provide NEs characterised by either everyone or nobody taking drugs, while non-linear prize functions lead to qualitatively different NEs with significantly more complex predictive characteristics. PMID:23691018

Crustal deformations in the Central Mediterranean derived from the WHAT A CAT GPS project.

NASA Astrophysics Data System (ADS)

Kaniuth, K.; Drewes, H.; Stuber, K.; Tremel, H.; Kahler, H.-G.; Peter, Y.; Zerbini, S.; Tonti, G.; Veis, G.; Fagard, H.

1999-03-01

The West Hellenic Arc Tectonics and Calabrian Arc Tectonics (WHAT A CAT) project aimes at monitoring crustal deformations in the Central Mediterranean by repeated GPS campaigns. The data set acquired so far is rather heterogeneous in terms of availability of GPS satellites, performance of the involved receiver systems and quality of the satellites' orbits. The paper presents the velocity estimates achieved using a modified version of the Bernese GPS software. Main characteristic of the solution strategy is the definition of station velocity parameters already on theobservation equation level.

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

Yang, C.

Almost every computer architect dreams of achieving high system performance with low implementation costs. A multigauge machine can reconfigure its data-path width, provide parallelism, achieve better resource utilization, and sometimes can trade computational precision for increased speed. A simple experimental method is used here to capture the main characteristics of multigauging. The measurements indicate evidence of near-optimal speedups. Adapting these ideas in designing parallel processors incurs low costs and provides flexibility. Several operational aspects of designing a multigauge machine are discussed as well. Thus, this research reports the technical, economical, and operational feasibility studies of multigauging.

Flowing Air-Water Cooled Slab Nd: Glass Laser

NASA Astrophysics Data System (ADS)

Lu, Baida; Cai, Bangwei; Liao, Y.; Xu, Shifa; Xin, Z.

1989-03-01

A zig-zag optical path slab geometry Nd: glass laser cooled through flowing air-water is developed by us. Theoretical studies on temperature distribution of slab and rod configurations in the unsteady state clarify the advantages of the slab geometry laser. The slab design and processing are also reported. In our experiments main laser output characteristics, e. g. laser efficiency, polarization, far-field divergence angle as well as resonator misalignment are investigated. The slab phosphate glass laser in combination with a crossed Porro-prism resonator demonstrates a good laser performance.

Preliminary design of a family of three close air support aircraft

NASA Technical Reports Server (NTRS)

Cox, Brian; Darrah, Paul; Lussier, Wayne; Mills, Nikos

1989-01-01

A family of three Close Air Support aircraft is presented. These aircraft are designed with commonality as the main design objective to reduce the life cycle cost. The aircraft are low wing, twin-boom, pusher turbo-prop configurations. The amount of information displayed to the pilot was reduced to a minimum to greatly simplify the cockpit. The aircraft met the mission specifications and the performance and cost characteristics compared well with other CAS aircraft. The concept of a family of CAS aircraft seems viable after preliminary design.

Thermodynamics of the sorption of water-soluble vitamins in reverse-phase high performance liquid chromatography

NASA Astrophysics Data System (ADS)

Chirkin, V. A.; Karpov, S. I.; Selemenev, V. F.

2012-12-01

The thermodynamics of the sorption of certain water-soluble vitamins on a C18 reverse phase from water-acetonitrile solutions of different compositions is studied. The thermodynamic characteristics of the investigated chromatographic systems are calculated. The dependences of standard molar enthalpy and changes in entropy when the sorbate transfers from the bulk solution to the surface layer on the concentration of the organic component in the mobile phase are analyzed. The boundaries for applying the main retention models describing the sorption of the investigated compounds are discussed.

Possibilities of further improvement of 1 s fluxgate variometers

NASA Astrophysics Data System (ADS)

Marusenkov, Andriy

2017-08-01

The paper discusses the possibility of improving temperature and noise characteristics of fluxgate variometers. The new fluxgate sensor with a Co-based amorphous ring core is described. This sensor is capable of improving the signal-to-noise ratio at the recording short-period geomagnetic variations. Besides the sensor performance, it is very important to create the high-stability compensation field that cancels the main Earth magnetic field inside the magnetic cores. For this purpose the new digitally controlled current source with low noise level and high temperature stability is developed.

Very High Reflectivity Supermirrors And Their Applications

NASA Astrophysics Data System (ADS)

Mezei, F.

1989-01-01

Very high reflectivity (some 95 % or better) supermirrors, with cut-off angles up to 2 times the critical angle of Ni coated simple total reflection neutron mirrors, can be produced using well established conventional deposition techniques. This performance makes applications involving multiple reflections and transmission geometries feasible, which in turn allow us to use more sophisticated neutron optical systems in order to optimize performance and minimize the amount a scarce supermirrors required. A key feature of several of these novel systems is the distribution of tasks between the several optical components achieving the desired performance by multiple action. The design and characteristics of a series of novel applications, such as polarizing cavities, collimators and guides, non-polarizing guides, beam compressors, deflectors and splitters (most of them tested or being implemented) are the main subjects of the present paper.

[Epidemiology of Internet Use by an Adolescent Population and its Relation with Sleep Habits].

PubMed

Ferreira, Carla; Ferreira, Helena; Vieira, Maria João; Costeira, Mónica; Branco, Liliana; Dias, Ângela; Macedo, Liliana

2017-08-31

In the last decades, the great technological development increased Internet popularity, emerging the concern about its overuse. The objectives of this study were to assess and characterize Internet use in adolescence, determine Internet addiction and clarify its association with sleep disorders and excessive daytime sleepiness. It was performed an observational, cross sectional and community-based study. The target were students attending 7th and 8th grades, to whom was applied an online self-report questionnaire to assess sociodemographic features, Internet use, Internet dependence, sleep characteristics and excessive daytime sleepiness. A total of 727 adolescents were included with a mean age 13 ± 0.9 years. Three-quarters of teenagers use Internet daily and 41% do it for three or more hours/day, mainly at home. The phone and laptop were the main devices used. Online games and social networks use were the main activities performed. Internet dependence was observed in 19% of adolescents, and it was associated with male gender, social networks use, mainly Twitter and Instagram use, self-perceived sleep problems, initial and middle insomnia and excessive daytime sleepiness (p < 0.05). The results confirm the highlight that Internet has in adolescents routine, who prioritize in their use access to social networks and online games, using single devices, less subject to parental control. The Internet addiction rate observed and its association with sleep alterations and daytime sleepiness emphasizes the importance of this issue.

An analytics of electricity consumption characteristics based on principal component analysis

NASA Astrophysics Data System (ADS)

Feng, Junshu

2018-02-01

Abstract . More detailed analysis of the electricity consumption characteristics can make demand side management (DSM) much more targeted. In this paper, an analytics of electricity consumption characteristics based on principal component analysis (PCA) is given, which the PCA method can be used in to extract the main typical characteristics of electricity consumers. Then, electricity consumption characteristics matrix is designed, which can make a comparison of different typical electricity consumption characteristics between different types of consumers, such as industrial consumers, commercial consumers and residents. In our case study, the electricity consumption has been mainly divided into four characteristics: extreme peak using, peak using, peak-shifting using and others. Moreover, it has been found that industrial consumers shift their peak load often, meanwhile commercial and residential consumers have more peak-time consumption. The conclusions can provide decision support of DSM for the government and power providers.

Enhanced affordable methods for assessment of material characteristics and consolidation effects on stone and mortar

NASA Astrophysics Data System (ADS)

Drdacky, M.; Slizkova, Z.

2012-04-01

In situ considerate testing of surface cohesion of historic stone and mortar materials suffers from a lack of suitable affordable non-destructive methods. The problem is mainly important for assessment of surface degradation characteristics and/or evaluation of effectiveness of consolidation treatment of degraded historic materials. The paper presents two innovations of simple testing methods which provide reliable data on material cohesion and water uptake. The so called "Scotch Tape Test" or peeling test has been introduced into the field of conservation for testing the cohesion qualities of historic materials mainly stone and renders in sixties without any standards or reliably verified recommendations for the above mentioned application in the conservation practice. Licentious use without adequate knowledge and sufficient understanding leads to non-comparable and non-reproducible as well as in many cases incorrect and severely biased results and assessments. Therefore, the authors after a research and comparative testing have established limits for its application, reliable procedures and a "standard" protocol for testing of cohesion characteristics of brittle and quasi brittle materials mainly mortars and stones. This article presents a detailed analysis of the peeling test procedures, and suggests recommendations for performing peeling tests and for evaluating the obtained results. Also in situ testing of material water uptake is a very basic and indispensable technique in conservation practice and it correlates significantly with some other material characteristics. The capillary properties of porous materials can be measured in situ using a Karsten tube and modified tools or methods which are quite cumbersome, and cannot be performed on inclined surfaces, e.g. vaults or ceilings. There are other difficulties with Karsten tube measurements, e.g. problems with fixing a heavy glass tube on vertical surfaces, a need for two operators, and soiling of the surface by the sealing putty. An innovative method has therefore been developed and tested at ITAM AS CR for measuring water absorption under low pressure. It enables continuous or manually controlled electronic measurements of water infusion into the surface and recording the acquired data. This measurement procedure reduces the number of operators, and it is more precise, more effective and faster. Two prototypes will be presented: one for continuous laboratory measurements and a portable device for in situ applications. The portable device has been tested in laboratory conditions and also in situ for its basic performance on various types of stone and plaster surfaces, including treated and untreated historic materials. The acquired data was evaluated using software specially written for this purpose in MatLab, and the results were compared with standard capillary water uptake measurements on prismatic columns. Working with the innovated tubes, measurements can be made on complex stone or plaster surfaces, e.g. sculptures in a dense network. This feature is especially appreciated by restorers making interventions on materials that have been treated previously.

The Impact of Professional Development and Student and Teacher Characteristics on the Quality of Postsecondary Goals

ERIC Educational Resources Information Center

Doren, Bonnie; Flannery, K. Brigid; Lombardi, Allison R.; Kato, Mimi McGrath

2013-01-01

This study examined (a) the main effects of professional development on the quality of postsecondary goals in employment and postsecondary education/training, (b) the main effects of student and teacher characteristics on goal quality, and (c) whether professional development moderated the relationship between the impact of these characteristics…

Geographical classification of apple based on hyperspectral imaging

NASA Astrophysics Data System (ADS)

Guo, Zhiming; Huang, Wenqian; Chen, Liping; Zhao, Chunjiang; Peng, Yankun

2013-05-01

Attribute of apple according to geographical origin is often recognized and appreciated by the consumers. It is usually an important factor to determine the price of a commercial product. Hyperspectral imaging technology and supervised pattern recognition was attempted to discriminate apple according to geographical origins in this work. Hyperspectral images of 207 Fuji apple samples were collected by hyperspectral camera (400-1000nm). Principal component analysis (PCA) was performed on hyperspectral imaging data to determine main efficient wavelength images, and then characteristic variables were extracted by texture analysis based on gray level co-occurrence matrix (GLCM) from dominant waveband image. All characteristic variables were obtained by fusing the data of images in efficient spectra. Support vector machine (SVM) was used to construct the classification model, and showed excellent performance in classification results. The total classification rate had the high classify accuracy of 92.75% in the training set and 89.86% in the prediction sets, respectively. The overall results demonstrated that the hyperspectral imaging technique coupled with SVM classifier can be efficiently utilized to discriminate Fuji apple according to geographical origins.

The Lowe-Andersen thermostat as an alternative to the dissipative particle dynamics in the mesoscopic simulation of entangled polymers.

PubMed

Khani, Shaghayegh; Yamanoi, Mikio; Maia, Joao

2013-05-07

Dissipative Particle Dynamics (DPD) has shown a great potential in studying the dynamics and rheological properties of soft matter; however, it is associated with deficiencies in describing the characteristics of entangled polymer melts. DPD deficiencies are usually correlated to the time integrating method and the unphysical bond crossings due to utilization of soft potentials. One shortcoming of DPD thermostat is the inability to produce real values of Schmidt number for fluids. In order to overcome this, an alternative Lowe-Anderson (LA) method, which successfully stabilizes the temperature, is used in the present work. Additionally, a segmental repulsive potential was introduced to avoid unphysical bond crossings. The performance of the method in simulating polymer systems is discussed by monitoring the static and dynamic characteristics of polymer chains and the results from the LA method are compared to standard DPD simulations. The performance of the model is evaluated on capturing the main shear flow properties of entangled polymer systems. Finally the linear and nonlinear viscoelastic properties of such systems are discussed.

[HPLC Fingerprint of QingGuangAn and Determination of the Main Components].

PubMed

Wang, Min; Shen, Bing-bing; Luo, Juan; Chen, Yang; Yang, Yu-pei; Chen, Sheng-huang

2015-10-01

To establish an HPLC fingerprint of ethanol extract of QingGuangAn, and to determine the contents of paeoniflorin and calycosin-7-glucosid. HPLC analysis was performed on an Agilent 1260 Infinity LC system and carried out at 35 degrees C on a column of GRACE Alltima C18 (250 mm x 4.6 mm, 5 μm). A binary gradient elution system was composed of acetonitrile (phase A) and water solution (phase B). Detection was performed at the wavelength of 254 nm, the mobile flow rate was 0.8 mL/min. A matrix including 20 variations (characteristic peaks area) and 10 samples was constructed for similarity evaluation. The results showed that the collected samples had a good similarity. A specificity fingerprint was produced and 20 characteristic peaks were designated. The content of paeoniflorin and calycosin-7-glucosid was 0.368 and 0.049 mg/g, respectively. It is a reliable, available and quick method for quality control of QingGuangAn,which provides some reference for the comparison of different extracting methods of QingGuangAn and the differences of pharmacodynamic.

Evaluation of Dewatering Performance and Fractal Characteristics of Alum Sludge

PubMed Central

Sun, Yongjun; Fan, Wei; Zheng, Huaili; Zhang, Yuxin; Li, Fengting; Chen, Wei

2015-01-01

The dewatering performance and fractal characteristics of alum sludge from a drinking-water treatment plant were investigated in this study. Variations in residual turbidity of supernatant, dry solid content (DS), specific resistance to filtration (SRF), floc size, fractal dimension, and zeta potential were analyzed. Sludge dewatering efficiency was evaluated by measuring both DS and SRF. Results showed that the optimum sludge dewatering efficiency was achieved at 16 mg∙L-1 flocculant dosage and pH 7. Under these conditions, the maximum DS was 54.6%, and the minimum SRF was 0.61 × 1010 m∙kg-1. Floc-size measurements demonstrated that high flocculant dosage significantly improved floc size. Correlation analysis further revealed a strong correlation between fractal dimension and floc size after flocculation. A strong correlation also existed between floc size and zeta potential, and flocculants with a higher cationic degree had a larger correlation coefficient between floc size and zeta potential. In the flocculation process, the main flocculation mechanisms involved adsorption bridging under an acidic condition, and a combination between charge neutralization and adsorption-bridging interaction under neutral and alkaline conditions. PMID:26121132

Personality characteristics and affective status related to cognitive test performance and gender in patients with memory complaints.

PubMed

Vestberg, Susanna; Passant, Ulla; Risberg, Jarl; Elfgren, Christina

2007-11-01

The aims are to study personality characteristics of patients with memory complaints and to assess the presence of objective (OMI) versus subjective (SMI) memory impairment, the affective status, as well as potential gender differences. The patients were assessed by means of a neuropsychiatric examination and a neuropsychological test-battery. The Swedish version of the revised NEO Personality Inventory (NEO PI-R) and the Hospital Anxiety and Depression Scale (HADS) were used. The 57 patients (38 women, 19 men, mean age 56.9) differed from the Swedish normative group in three of the five personality factors: neuroticism, extraversion and agreeableness. This was mainly because of the scores of the female patients. Approximately half of the patients had OMI. No differences regarding personality factors or affective status were found between OMI and SMI patients. The female patients scored significantly higher than the male patients on symptoms of anxiety and depression. Neuroticism and symptoms of depression interacted with memory performance and gender. Our findings demonstrate the importance of applying an objective assessment of memory functions and a gender perspective when studying patients with memory complaints.

KBGIS-II: A knowledge-based geographic information system

NASA Technical Reports Server (NTRS)

Smith, Terence; Peuquet, Donna; Menon, Sudhakar; Agarwal, Pankaj

1986-01-01

The architecture and working of a recently implemented Knowledge-Based Geographic Information System (KBGIS-II), designed to satisfy several general criteria for the GIS, is described. The system has four major functions including query-answering, learning and editing. The main query finds constrained locations for spatial objects that are describable in a predicate-calculus based spatial object language. The main search procedures include a family of constraint-satisfaction procedures that use a spatial object knowledge base to search efficiently for complex spatial objects in large, multilayered spatial data bases. These data bases are represented in quadtree form. The search strategy is designed to reduce the computational cost of search in the average case. The learning capabilities of the system include the addition of new locations of complex spatial objects to the knowledge base as queries are answered, and the ability to learn inductively definitions of new spatial objects from examples. The new definitions are added to the knowledge base by the system. The system is performing all its designated tasks successfully. Future reports will relate performance characteristics of the system.

Spanish Heart Transplant Registry. 28th Official Report of the Spanish Society of Cardiology Working Group on Heart Failure (1984-2016).

PubMed

González-Vílchez, Francisco; Gómez-Bueno, Manuel; Almenar-Bonet, Luis; Crespo-Leiro, María G; Arizón Del Prado, José M; Delgado-Jiménez, Juan; Sousa-Casasnovas, Iago; Brossa-Loidi, Vicens; Sobrino-Márquez, José Manuel; González-Costelo, José

2017-12-01

The present article reports the characteristics and results of heart transplants in Spain since this therapeutic modality was first used in May 1984. We summarize the main features of recipients, donors, surgical procedures, and outcomes of all cardiac transplants performed in Spain up to December 31, 2016. A total of 281 cardiac transplants were performed in 2016. The whole historical series consisted of 7869 procedures. The main features of transplant procedures in 2016 were similar to those observed in recent years. A high percentage of procedures were urgent, particularly those with use of pretransplant continuous-flow left ventricular assist devices (19.1% of all transplants). Survival significantly improved in the last decade compared with previous periods. During the last few years, transplant activity in Spain has remained steady, with approximately 250-300 transplants/year. Despite a more complex clinical context, survival has improved in recent years. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Wireless Infrastructure M2M Network For Distributed Power Grid Monitoring

PubMed Central

Gharavi, Hamid; Hu, Bin

2018-01-01

With the massive integration of distributed renewable energy sources (RESs) into the power system, the demand for timely and reliable network quality monitoring, control, and fault analysis is rapidly growing. Following the successful deployment of Phasor Measurement Units (PMUs) in transmission systems for power monitoring, a new opportunity to utilize PMU measurement data for power quality assessment in distribution grid systems is emerging. The main problem however, is that a distribution grid system does not normally have the support of an infrastructure network. Therefore, the main objective in this paper is to develop a Machine-to-Machine (M2M) communication network that can support wide ranging sensory data, including high rate synchrophasor data for real-time communication. In particular, we evaluate the suitability of the emerging IEEE 802.11ah standard by exploiting its important features, such as classifying the power grid sensory data into different categories according to their traffic characteristics. For performance evaluation we use our hardware in the loop grid communication network testbed to access the performance of the network. PMID:29503505

Different Lactobacillus populations dominate in "Chorizo de León" manufacturing performed in different production plants.

PubMed

Quijada, Narciso M; De Filippis, Francesca; Sanz, José Javier; García-Fernández, María Del Camino; Rodríguez-Lázaro, David; Ercolini, Danilo; Hernández, Marta

2018-04-01

"Chorizo de Léon" is a high-value Spanish dry fermented sausage traditionally manufactured without the use of starter cultures, owing to the activity of a house-specific autochthonous microbiota that naturally contaminates the meat from the environment, the equipment and the raw materials. Lactic acid bacteria (particularly Lactobacillus) and coagulase-negative cocci (mainly Staphylococcus) have been reported as the most important bacterial groups regarding the organoleptic and safety properties of the dry fermented sausages. In this study, samples from raw minced meat to final products were taken from five different producers and the microbial diversity was investigated by high-throughput sequencing of 16S rRNA gene amplicons. The diverse microbial composition observed during the first stages of "Chorizo de Léon" evolved during ripening to a microbiota mainly composed by Lactobacillus in the final product. Oligotyping performed on 16S rRNA gene sequences of Lactobacillus and Staphylococcus populations revealed sub-genus level diversity within the different manufacturers, likely responsible of the characteristic organoleptic properties of the products from different companies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance Parameters Analysis of an XD3P Peugeot Engine Using Artificial Neural Networks (ANN) Concept in MATLAB

NASA Astrophysics Data System (ADS)

Rangaswamy, T.; Vidhyashankar, S.; Madhusudan, M.; Bharath Shekar, H. R.

2015-04-01

The current trends of engineering follow the basic rule of innovation in mechanical engineering aspects. For the engineers to be efficient, problem solving aspects need to be viewed in a multidimensional perspective. One such methodology implemented is the fusion of technologies from other disciplines in order to solve the problems. This paper mainly deals with the application of Neural Networks in order to analyze the performance parameters of an XD3P Peugeot engine (used in Ministry of Defence). The basic propaganda of the work is divided into two main working stages. In the former stage, experimentation of an IC engine is carried out in order to obtain the primary data. In the latter stage the primary database formed is used to design and implement a predictive neural network in order to analyze the output parameters variation with respect to each other. A mathematical governing equation for the neural network is obtained. The obtained polynomial equation describes the characteristic behavior of the built neural network system. Finally, a comparative study of the results is carried out.

The morphometry of the laryngeal phonatory system - base of the anatomical study of the voice aptitudes.

PubMed

Hînganu, Marius Valeriu; Cozma, Romică Sebastian; Ciochină, Paula; Scutariu, Irina Andreea; Asimionoaiei-Simionescu, Cristina; Hînganu, Delia

2017-01-01

Speaking is one of the characteristics of the human race and the main factor that has marked our progress over time. The singing voice is the crowning of the speech act and the main component of the lyrical manifestation of personality. Doctors in various fields, but especially anatomists have been concerned about discovering how the voice and the substrate of its variability are formed, but these aspects have not yet been fully deciphered. This study is the starting point in our research on the phonation system, organized on three levels: laryngeal, oral, palatinal, pharyngeal, epiglottal and nasal. We performed the dissection of seven embalmed anatomical parts, on which, we made measurements of the anatomical elements involved in the phonation. We performed the same measurements on a batch of seven adults investigated by magnetic resonance imaging (MRI). The results were entered into the statistical calculation formulas and compared with each other and with the literature. The results of the study show that certain values resulting from the calculation formulas remain constant and others vary greatly from each individuals and gender.

Wireless Infrastructure M2M Network For Distributed Power Grid Monitoring.

PubMed

Gharavi, Hamid; Hu, Bin

2017-01-01

With the massive integration of distributed renewable energy sources (RESs) into the power system, the demand for timely and reliable network quality monitoring, control, and fault analysis is rapidly growing. Following the successful deployment of Phasor Measurement Units (PMUs) in transmission systems for power monitoring, a new opportunity to utilize PMU measurement data for power quality assessment in distribution grid systems is emerging. The main problem however, is that a distribution grid system does not normally have the support of an infrastructure network. Therefore, the main objective in this paper is to develop a Machine-to-Machine (M2M) communication network that can support wide ranging sensory data, including high rate synchrophasor data for real-time communication. In particular, we evaluate the suitability of the emerging IEEE 802.11ah standard by exploiting its important features, such as classifying the power grid sensory data into different categories according to their traffic characteristics. For performance evaluation we use our hardware in the loop grid communication network testbed to access the performance of the network.

Exploring performance obstacles of intensive care nurses.

PubMed

Gurses, Ayse P; Carayon, Pascale

2009-05-01

High nursing workload, poor patient safety, and poor nursing quality of working life (QWL) are major issues in intensive care units (ICUs). Characteristics of the ICU and performance obstacles may contribute to these issues. The goal of this study was to comprehensively identify the performance obstacles perceived by ICU nurses. We used a qualitative research design and conducted semi-structured interviews with 15 ICU nurses of a medical-surgical ICU. Based on this qualitative study and a previously reported quantitative study, we identified seven main types of performance obstacles experienced by ICU nurses. Obstacles related to the physical environment (e.g., noise, amount of space), family relations (e.g., distractions caused by family, lack of time to spend with family), and equipment (e.g., unavailability, misplacement) were the most frequently experienced performance obstacles. The qualitative interview data provided rich information regarding the factors contributing to the performance obstacles. Overall, ICU nurses experience a variety of performance obstacles in their work on a daily basis. Future research is needed to understand the impact of performance obstacles on nursing workload, nursing QWL, and quality and safety of care.

Operator performance evaluation using multi criteria decision making methods

NASA Astrophysics Data System (ADS)

Rani, Ruzanita Mat; Ismail, Wan Rosmanira; Razali, Siti Fatihah

2014-06-01

Operator performance evaluation is a very important operation in labor-intensive manufacturing industry because the company's productivity depends on the performance of its operators. The aims of operator performance evaluation are to give feedback to operators on their performance, to increase company's productivity and to identify strengths and weaknesses of each operator. In this paper, six multi criteria decision making methods; Analytical Hierarchy Process (AHP), fuzzy AHP (FAHP), ELECTRE, PROMETHEE II, Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) are used to evaluate the operators' performance and to rank the operators. The performance evaluation is based on six main criteria; competency, experience and skill, teamwork and time punctuality, personal characteristics, capability and outcome. The study was conducted at one of the SME food manufacturing companies in Selangor. From the study, it is found that AHP and FAHP yielded the "outcome" criteria as the most important criteria. The results of operator performance evaluation showed that the same operator is ranked the first using all six methods.

Causes and Characteristics of Death in Intensive Care Units: A Prospective Multicenter Study.

PubMed

Orban, Jean-Christophe; Walrave, Yannick; Mongardon, Nicolas; Allaouchiche, Bernard; Argaud, Laurent; Aubrun, Frédéric; Barjon, Geneviève; Constantin, Jean-Michel; Dhonneur, Gilles; Durand-Gasselin, Jacques; Dupont, Hervé; Genestal, Michèle; Goguey, Chloé; Goutorbe, Philippe; Guidet, Bertrand; Hyvernat, Hervé; Jaber, Samir; Lefrant, Jean-Yves; Mallédant, Yannick; Morel, Jerôme; Ouattara, Alexandre; Pichon, Nicolas; Guérin Robardey, Anne-Marie; Sirodot, Michel; Theissen, Alexandre; Wiramus, Sandrine; Zieleskiewicz, Laurent; Leone, Marc; Ichai, Carole

2017-05-01

Different modes of death are described in selected populations, but few data report the characteristics of death in a general intensive care unit population. This study analyzed the causes and characteristics of death of critically ill patients and compared anticipated death patients to unexpected death counterparts. An observational multicenter cohort study was performed in 96 intensive care units. During 1 yr, each intensive care unit was randomized to participate during a 1-month period. Demographic data, characteristics of organ failures (Sequential Organ Failure Assessment subscore greater than or equal to 3), and organ supports were collected on all patients who died in the intensive care unit. Modes of death were defined as anticipated (after withdrawal or withholding of treatment or brain death) or unexpected (despite engagement of full-level care or sudden refractory cardiac arrest). A total of 698 patients were included during the study period. At the time of death, 84% had one or more organ failures (mainly hemodynamic) and 89% required at least one organ support (mainly mechanical ventilation). Deaths were considered unexpected and anticipated in 225 and 473 cases, respectively. Compared to its anticipated counterpart, unexpected death occurred earlier (1 day vs. 5 days; P< 0.001) and had fewer organ failures (1 [1 to 2] vs. 1 [1 to 3]; P< 0.01) and more organ supports (2 [2 to 3] vs. 1 [1 to 2]; P< 0.01). Withdrawal or withholding of treatments accounted for half of the deaths. In a general intensive care unit population, the majority of patients present with at least one organ failure at the time of death. Anticipated and unexpected deaths represent two different modes of dying and exhibit profiles reflecting the different pathophysiologic underlying mechanisms.

Neuropsychiatric symptoms as the main determinant of caregiver burden in Alzheimer’s disease

PubMed Central

Kochhann, Renata; Borba, Ericksen; Cerveira, Maria Otília; Onyszko, Diego; de Jesus, Alyne; Forster, Letícia; Franciscatto, Luisa; Godinho, Cláudia; Camozzato, Ana Luiza; Chaves, Márcia Lorena F.

2011-01-01

Caregiver burden is common in Alzheimer’s disease (AD), decreasing the quality of life among caregivers and patients. Projections of aging and aging-related diseases such as AD in developing countries justify additional data about this issue because people living in these countries have shown similarly high levels of caregiver strain as in the developed world. Objective The aim of this study was to analyze the association of AD caregivers’ burden with patients’ neuropsychiatric symptoms (NPS), cognitive status, severity of dementia, functional capacity, caregiver sociodemographic characteristics, and the characteristics of care provided by caregivers. Methods A cross-sectional study was conducted in a sample of 39 consecutive AD patients and their primary caregivers. NPS were evaluated using the Neuropsychiatric Inventory (NPI). Severity of dementia was assessed with the Clinical Dementia Rating (CDR) scale. Functional capacity was assessed using the Katz and Lawton scales. The burden level was rated using the Burden Interview (BI). Sociodemographic characteristics of caregivers and the characteristics of care provided by them were evaluated. The Mann-Whitney U-test, Kruskal-Wallis test and Spearman’s rho coefficient were performed. Results The BI had a moderate correlation with NPI intensity (rho=0.563), p<001. Female caregivers reported a greater level of burden (p=0.031) than male caregivers. The other variables were not significantly associated to caregiver burden. Conclusion NPS were the main determinant of burden in primary caregivers of AD patients. This result underscores the need for prevention and treatment of these symptoms. Sex also had an effect on caregiver burden, but the small male sample in this study precludes the generalization of this finding. PMID:29213745

Fundamental Characteristics For Building Dymanics Obtained From Microtremors Measurements.

NASA Astrophysics Data System (ADS)

Enomoto, T.; Abeki, N.; Kuramochi, D.; Lanuza, A.; Gonzalez, J.; Schmitz, M.; Navarro, M.

We are performing the international joint research investigations for the seismic disaster mitigation in Metro Manila between Philippine and Japan from 1994, in Caracas between Venezuela and Japan from 1996 and also in Almeria and Granada between Spain and Japan from 1996. We have made the microtremor measurements at Reinforced Concrete (RC) buildings existed in these cities and evaluated the dynamical characteristics of RC buildings, natural period and damping factor. Even if it·fs necessary to have some discussions about the accuracy of microtremor measurement in order to evaluate the dynamical characteristics because of small amplitude range phenomena. However, the microtremor measurement method is a simple, low cost and realistic method in order to observe and investigate the actual dynamical behavior for obtaining the useful information in many countries. In these international joint research works, we settled the main object to the getting useful information of building dynamical characteristics for the seismic disaster mitigation. So, we observed microtremors at the top floor of several kinds of buildings which have the different conditions, for examples, existed place, building type, dimensional scale and number of stories etc. Then we realized the evaluation of natural period and responded damping factor of building depending on the building conditions as a statistical tendencies. In this paper, mainly we would like to present the investigated results of regression relationship between the natural period of RC building and the number of stories in Philippine and Venezuela, respectively. and also, we summarized the relationship between the natural period of RC building and damping factor considering the surrounding soil condition. We thought that these relations are reasonable and believable results in the small amplitude range evaluated from microtremors.

Integrated thruster assembly program

NASA Technical Reports Server (NTRS)

1973-01-01

The program is reported which has provided technology for a long life, high performing, integrated ACPS thruster assembly suitable for use in 100 typical flights of a space shuttle vehicle over a ten year period. The four integrated thruster assemblies (ITA) fabricated consisted of: propellant injector; a capacitive discharge, air gap torch type igniter assembly; fast response igniter and main propellant valves; and a combined regen-dump film cooled chamber. These flightweight 6672 N (1500 lb) thruster assemblies employed GH2/GO2 as propellants at a chamber pressure of 207 N/sq cm (300 psia). Test data were obtained on thrusted performance, thermal and hydraulic characteristics, dynamic response in pulsing, and cycle life. One thruster was fired in excess of 42,000 times.

Whole-machine calibration approach for phased array radar with self-test

NASA Astrophysics Data System (ADS)

Shen, Kai; Yao, Zhi-Cheng; Zhang, Jin-Chang; Yang, Jian

2017-06-01

The performance of the missile-borne phased array radar is greatly influenced by the inter-channel amplitude and phase inconsistencies. In order to ensure its performance, the amplitude and the phase characteristics of radar should be calibrated. Commonly used methods mainly focus on antenna calibration, such as FFT, REV, etc. However, the radar channel also contains T / R components, channels, ADC and messenger. In order to achieve on-based phased array radar amplitude information for rapid machine calibration and compensation, we adopt a high-precision plane scanning test platform for phase amplitude test. A calibration approach for the whole channel system based on the radar frequency source test is proposed. Finally, the advantages and the application prospect of this approach are analysed.

[Osteoid osteoma in children: 5 cases treated with electrocoagulation].

PubMed

Gilliaux, O; de Wispelaere, J-F; Charlier, H; Bodart, E

2012-11-01

Osteoid osteoma is a benign bone tumor. Its diagnosis is often delayed despite typical symptoms: severe pain mainly situated on the lower limbs and characteristically worse at night. Once diagnosed, an antalgic treatment by aspirin is well known to be very effective in relieving pain. Osteoid osteoma will resolve spontaneously. If symptoms persist despite the use of aspirin, surgery can be performed to remove the tumor. Percutaneous electrocoagulation can be performed instead of surgical resection as a less invasive procedure. The success rate of surgery and percutaneous electrocoagulation is comparable. We reviewed the cases of 5 patients who were hospitalized in our institution for percutaneous electrocoagulation of an osteoid osteoma. We compared them to the literature. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Investigation of an Axial Fan—Blade Stress and Vibration Due to Aerodynamic Pressure Field and Centrifugal Effects

NASA Astrophysics Data System (ADS)

Xu, Cheng; Amano, Ryoichi Samuel; Lee, Eng Kwong

A 1.829m (6ft) diameter industrial large flow-rate axial fan operated at 1770rpm was studied experimentally in laboratory conditions. The flow characteristics on the fan blade surfaces were investigated by measuring the pressure distributions on the blade suction and pressure surfaces and the results were discussed by comparing with analytical formulations and CFD. Flow visualizations were also performed to validate the flow characteristics near the blade surface and it was demonstrated that the flow characteristics near the fan blade surface were dominated by the centrifugal force of the fan rotation which resulted in strong three-dimensional flows. The time-dependent pressure measurement showed that the pressure oscillations on the fan blade were significantly dominated by vortex shedding from the fan blades. It was further demonstrated that the pressure distributions during the fan start-up were highly unsteady, and the main frequency variation of the static pressure was much smaller than the fan rotational frequency. The time-dependent pressure measurement when the fan operated at a constant speed showed that the magnitude of the blade pressure variation with time and the main variation frequency was much smaller than the fan rotational frequency. The pressure variations that were related to the vortex shedding were slightly smaller than the fan rotational frequency. The strain gages were used to measure the blade stress and the results were compared with FEA results.

Clinical validation of the nursing diagnosis of dysfunctional family processes related to alcoholism.

PubMed

Mangueira, Suzana de Oliveira; Lopes, Marcos Venícios de Oliveira

2016-10-01

To evaluate the clinical validity indicators for the nursing diagnosis of dysfunctional family processes related to alcohol abuse. Alcoholism is a chronic disease that negatively affects family relationships. Studies on the nursing diagnosis of dysfunctional family processes are scarce in the literature. This diagnosis is currently composed of 115 defining characteristics, hindering their use in practice and highlighting the need for clinical validation. This was a diagnostic accuracy study. A sample of 110 alcoholics admitted to a reference centre for alcohol treatment was assessed during the second half of 2013 for the presence or absence of the defining characteristics of the diagnosis. Operational definitions were created for each defining characteristic based on concept analysis and experts evaluated the content of these definitions. Diagnostic accuracy measures were calculated from latent class models with random effects. All 89 clinical indicators were found in the sample and a set of 24 clinical indicators was identified as clinically valid for a diagnostic screening for family dysfunction from the report of alcoholics. Main clinical indicators with high specificity included sexual abuse, disturbance in academic performance in children and manipulation. The main indicators that showed high sensitivity values were distress, loss, anxiety, low self-esteem, confusion, embarrassment, insecurity, anger, loneliness, deterioration in family relationships and disturbance in family dynamics. Eighteen clinical indicators showed a high capacity for diagnostic screening for alcoholics (high sensitivity) and six indicators can be used for confirmatory diagnosis (high specificity). © 2016 John Wiley & Sons Ltd.

Analysis on concentration variety characteristics of SO2/NO2 in Chengdu city, southwest China

NASA Astrophysics Data System (ADS)

Wang, C.; Xiao, T.; Luo, Q.; WU, L.

2017-12-01

SO2 and NO2, the important gaseous precursors of atmospheric fine particles, are closely related to urban air quality. Chengdu located in the western China, is the capital city of Sichuan province. Though Sichuan province is one of four heavily polluted areas in China, the air pollution research in Chengdu is in a relative lack, when compared to developed cities as Beijing, Guangzhou, etc. This paper, based on characteristics of SO2 and NO2 in Chengdu, shows that: the average concentration of SO2, NO2 was 25.29 (mainly in the rage 10-40 ), 64.41 (mainly in the range 30-80 ), respectively. There is a similar annual and seasonal variation for them, yet significant differences in diurnal variation. Except summer, the air condition in Chengdu is seriously affected by SO2 and NO2, while the latter plays a more significant role. Multiple regression has good fitting performance to the diurnal variation in Chengdu. The purification efficiency of precipitation in different magnitude is also discussed. Key words: Chengdu; Pollution gas; Variety characteristics Acknowledgements: This study was supported by Pollution program in Wenjiang District, National Natural Science Foundation of China Fund Project (91337215,41575066), National Science and Technology Support Program(2015BAC03B05),Special Fund for Meteorological Re-search in the Public Interest (GYHY201406015),National Key Basic Research Program (2013CB733206), and Risk Assessment System of Significant Climate Events in Tibet (14H046), Scientific Research Foundation of CUIT (CRF201606)

Lower limb alignment characteristics are not associated with running injuries in runners: Prospective cohort study.

PubMed

Hespanhol Junior, Luiz Carlos; de Carvalho, Aline Carla Araújo; Costa, Leonardo Oliveira Pena; Lopes, Alexandre Dias

2016-11-01

There is conflicting evidence on the association between lower limb alignment characteristics and the incidence of running-related injury (RRI). Therefore, the primary aim of this study was to investigate the association between lower limb alignment characteristics and the incidence proportion of RRI in a convenience sample of recreational runners. A total of 89 recreational runners were included in this prospective cohort study. These participants had been running for at least six months and were injury-free at baseline. Lower limb alignment measurements were conducted in order to calculate lower limb discrepancy, Q-angle, subtalar angle and plantar index. All participants also answered a baseline and biweekly online surveys about their running routine, history of RRI and newly developed RRI over a period of 12 weeks. The prevalence of previous RRI and the 12-week incidence proportion of new RRI were calculated. Logistic regression analysis was performed to estimate the association between lower limb length discrepancy, Q-angle, subtalar angle and plantar ach index with the incidence proportion of RRI. The prevalence of previous RRI was 55.1% (n = 49). The 12-week incidence proportion of new RRI was 27.0% (n = 24). Muscle injuries and tendinopathies were the main types of RRI identified. The lower leg and the knee were the main anatomical regions affected. We did not find significant associations between lower limb length discrepancy, Q-angle, subtalar angle and plantar arch index and injury occurrence.

Judgment of infant cry: The roles of acoustic characteristics and sociodemographic characteristics.

PubMed

Esposito, Gianluca; Nakazawa, Jun; Venuti, Paola; Bornstein, Marc H

2015-04-01

Adult judgments of infant cry are determined by both acoustic properties of the cry and listener sociodemographic characteristics. The main purpose of this research was to investigate how these two sources shape adult judgments of infant cry. We systematically manipulated both the acoustic properties of infant cries and contrasted listener sociodemographic characteristics. Then, we asked participants to listen to several acoustic manipulations of infant cries and to judge the level of distress the infant was expressing and the level of distress participants felt when listening. Finally, as a contrasting condition, participants estimated the age of the crying infant. Using tree-based models, we found that judgments of the level of distress the infant was expressing as well as the level of distress listeners felt are mainly accounted for by select acoustic properties of infant cry (proportion of sound/pause, fundamental frequency, and number of utterances), whereas age estimates of a crying infant are determined mainly by listener sociodemographic characteristics (gender and parental status). Implications for understanding infant cry and its effects as well as early caregiver-infant interactions are discussed.

Immunomodulatory activity and partial characterisation of polysaccharides from Momordica charantia.

PubMed

Deng, Yuan-Yuan; Yi, Yang; Zhang, Li-Fang; Zhang, Rui-Fen; Zhang, Yan; Wei, Zhen-Cheng; Tang, Xiao-Jun; Zhang, Ming-Wei

2014-08-29

Momordica charantia Linn. is used as an edible and medicinal vegetable in sub-tropical areas. Until now, studies on its composition and related activities have been confined to compounds of low molecular mass, and no data have been reported concerning the plant's polysaccharides. In this work, a crude polysaccharide of M. charantia (MCP) fruit was isolated by hot water extraction and then purified using DEAE-52 cellulose anion-exchange chromatography to produce two main fractions MCP1 and MCP2. The immunomodulatory effects and physicochemical characteristics of these fractions were investigated in vitro and in vivo. The results showed that intragastric administration of 150 or 300 mg·kg-·d⁻¹ of MCP significantly increased the carbolic particle clearance index, serum haemolysin production, spleen index, thymus index and NK cell cytotoxicity to normal control levels in cyclophosphamide (Cy)-induced immunosuppressed mice. Both MCP1 and MCP2 effectively stimulated normal and concanavalin A-induced splenic lymphocyte proliferation in vitro at various doses. The average molecular weights of MCP1 and MCP2, which were measured using high-performance gel permeation chromatography, were 8.55×10⁴ Da and 4.41×10⁵ Da, respectively. Both fractions exhibited characteristic polysaccharide bands in their Fourier transform infrared spectrum. MCP1 is mainly composed of glucose and galactose, and MCP2 is mainly composed of glucose, mannose and galactose. The results indicate that MCP and its fractions have good potential as immunotherapeutic adjuvants.

Investigation of Prediction Method and Fundamental Thermo-decomposition Properties on Gasification of Woody Biomass

NASA Astrophysics Data System (ADS)

Morita, Akihiro

Recently, development of energy transfer technology based on woody biomass remarkably has been forwarding accompanied biomass boom for gasification and liquefaction. To elevate on yield of energy into biomass for transportation and exergy is extremely important for essential utilization and production of bio-fuels. Because, conversion to bio-fuel must be discussion in detail thermo-decomposition characteristics for biomass main composition formed on cellulose and hemicelluloses, lignin. In this research, we analyze thermo-decomposition characteristics of each biomass main composition on both active (air) and passive (N2) atmosphere. Especially, we suggest predict model of gasification based on change of atomic carbon ratio with thermo-decomposition. 1) Even if it heat-treats cedar chip by 473K, loss of energy hardly produces it. From this, it acquired that the substance contributed to weight reduction was a low ingredient of energy value. 2) If cedar chip is heated in the 473K around, it can be predicted that the substance with a low energy value like water or acetic acid has arisen by thermal decomposition. It suggested that the transportation performance of the biomass improved by choosing and eliminating these. 3) Each ingredient of hydrogen, nitrogen, and oxygen which dissipated in the gasification process acquired that it was direct proportion to the carbonaceous dissipation rate. 4) The action at the time of thermo-decomposition of (the carbon, hydrogen, nitrogen, oxygen which are) the main constituent factors of the biomass suggested a possibility of being predicted by a statistical method.

[Standard algorithm of molecular typing of Yersinia pestis strains].

PubMed

Eroshenko, G A; Odinokov, G N; Kukleva, L M; Pavlova, A I; Krasnov, Ia M; Shavina, N Iu; Guseva, N P; Vinogradova, N A; Kutyrev, V V

2012-01-01

Development of the standard algorithm of molecular typing of Yersinia pestis that ensures establishing of subspecies, biovar and focus membership of the studied isolate. Determination of the characteristic strain genotypes of plague infectious agent of main and nonmain subspecies from various natural foci of plague of the Russian Federation and the near abroad. Genotyping of 192 natural Y. pestis strains of main and nonmain subspecies was performed by using PCR methods, multilocus sequencing and multilocus analysis of variable tandem repeat number. A standard algorithm of molecular typing of plague infectious agent including several stages of Yersinia pestis differentiation by membership: in main and nonmain subspecies, various biovars of the main subspecies, specific subspecies; natural foci and geographic territories was developed. The algorithm is based on 3 typing methods--PCR, multilocus sequence typing and multilocus analysis of variable tandem repeat number using standard DNA targets--life support genes (terC, ilvN, inv, glpD, napA, rhaS and araC) and 7 loci of variable tandem repeats (ms01, ms04, ms06, ms07, ms46, ms62, ms70). The effectiveness of the developed algorithm is shown on the large number of natural Y. pestis strains. Characteristic sequence types of Y. pestis strains of various subspecies and biovars as well as MLVA7 genotypes of strains from natural foci of plague of the Russian Federation and the near abroad were established. The application of the developed algorithm will increase the effectiveness of epidemiologic monitoring of plague infectious agent, and analysis of epidemics and outbreaks of plague with establishing the source of origin of the strain and routes of introduction of the infection.

Shuttle STS-2 mission communication systems RF coverage and performance predictions. Volume 1: Ascent

NASA Technical Reports Server (NTRS)

Porter, J. A.; Gibson, J. S.; Kroll, Q. D.; Loh, Y. C.

1981-01-01

The RF communications capabilities and nominally expected performance for the ascent phase of the second orbital flight of the shuttle are provided. Predicted performance is given mainly in the form of plots of signal strength versus elapsed mission time for the STDN (downlink) and shuttle orbiter (uplink) receivers for the S-band PM and FM, and UHF systems. Performance of the NAV and landing RF systems is treated for RTLS abort, since in this case the spacecraft will loop around and return to the launch site. NAV and landing RF systems include TACAN, MSBLS, and C-band altimeter. Signal strength plots were produced by a computer program which combines the spacecraft trajectory, antenna patterns, transmit and receive performance characteristics, and system mathematical models. When available, measured spacecraft parameters were used in the predictions; otherwise, specified values were used. Specified ground station parameter values were also used. Thresholds and other criteria on the graphs are explained.

DET/MPS - The GSFC Energy Balance Programs

NASA Technical Reports Server (NTRS)

Jagielski, J. M.

1994-01-01

Direct Energy Transfer (DET) and MultiMission Spacecraft Modular Power System (MPS) computer programs perform mathematical modeling and simulation to aid in design and analysis of DET and MPS spacecraft power system performance in order to determine energy balance of subsystem. DET spacecraft power system feeds output of solar photovoltaic array and nickel cadmium batteries directly to spacecraft bus. MPS system, Standard Power Regulator Unit (SPRU) utilized to operate array at array's peak power point. DET and MPS perform minute-by-minute simulation of performance of power system. Results of simulation focus mainly on output of solar array and characteristics of batteries. Both packages limited in terms of orbital mechanics, they have sufficient capability to calculate data on eclipses and performance of arrays for circular or near-circular orbits. DET and MPS written in FORTRAN-77 with some VAX FORTRAN-type extensions. Both available in three versions: GSC-13374, for DEC VAX-series computers running VMS. GSC-13443, for UNIX-based computers. GSC-13444, for Apple Macintosh computers.

Hover and forward flight acoustics and performance of a small-scale helicopter rotor system

NASA Technical Reports Server (NTRS)

Kitaplioglu, C.; Shinoda, P.

1985-01-01

A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the NASA Ames 40- by 80- Foot Wind Tunnel. Subsequently, it was tested in forward flight in the Ames 7- by 10-Foot Wind Tunnel. The primary objective of the tests was to obtain performance and noise data on a small-scale rotor at various thrust coefficients, tip Mach numbers, and, in the later case, various advance ratios, for comparisons with similar existing data on full-scale helicopter rotors. This comparison yielded a preliminary evaluation of the scaling of helicopter rotor performance and acoustic radiation in hover and in forward flight. Correlation between model-scale and full-scale performance and acoustics was quite good in hover. In forward flight, however, there were significant differences in both performance and acoustic characteristics. A secondary objective was to contribute to a data base that will permit the estimation of facility effects on acoustic testing.

Influence of triaxial braid denier on ribbon-based fiber reinforced dental composites.

PubMed

Karbhari, Vistasp M; Wang, Qiang

2007-08-01

The aim of the study was to compare the mechanical characteristics of two ultrahigh molecular weight polyethylene (UHMWPE) fiber-based triaxial braided reinforcements having different denier braider yarns used in fiber reinforced dental composites to elucidate differences in response and damage under flexural loading. Two commercially available triaxial braided reinforcing systems, differing in denier of the axial and braider yarns, using ultra high molecular weight polyethylene (UHMWPE) were used to reinforce rectangular bars towards the tensile surface which were tested in flexure. Mechanical characteristics including energy absorption were determined and results were compared based on Tukey post-test analysis and Weibull probability. Limited fatigue testing was also conducted for 100, 1000, and 10,000 cycles at a level of 75% of peak load. The effect of the braid denier on damage mechanisms was studied microscopically. The use of the triaxially braided ribbon as fiber reinforcement in the dental composite results in significant enhancement in flexural performance over that of the unreinforced dental composite (179% and 183% increase for the "thin" and "dense" braid reinforced specimens, respectively), with a fairly ductile, non-catastrophic post-peak response. With the exception of strain at peak load, there was very little difference between the performance from the two braid architectures. The intrinsic nature of the triaxial braid also results in very little decrease in flexural strength as a result of fatigue cycling at 75% of peak load. Use of the braids results in peak load levels which are substantially higher than those corresponding to points at which the dentin and unreinforced dental composites would fail. The total energy at peak load level is 56.8 and 60.7 times that at the level that dentin would fail if the reinforcement were not placed for the "thin" and "dense" reinforced braid reinforced composites, respectively. The research shows that in addition to enhancement in flexural performance characteristics, the use of a triaxial braid provides significant damage tolerance and fatigue resistance through its characteristic architecture wherein axial fibers are uncrimped and braider yarns provide shear resistance and enable local arrest of microcracks. Further, it is demonstrated that the decrease in braider yarn denier does not have a detrimental effect, with differences in performance characteristics, being in the main, statistically insignificant. This allows use of thinner reinforcement which provides ease of placement and better bonding without loss in performance.

Study utilization of extractable petroleum hydrocarbons biodegradation waste as the main material for making solid fuels

NASA Astrophysics Data System (ADS)

Hendrianie, Nuniek; Juliastuti, Sri Rachmania; Ar-rosyidah, Fanny Husna; Rochman, Hilal Abdur

2017-05-01

Nowadays the existence of energy sources of oil and was limited. Therefore, it was important to searching for new innovations of renewable energy sources by utilizing the waste into a source of energy. On the other hand, the process of extractable petroleum hydrocarbons biodegradation generated sludge that had calorific value and untapped. Because of the need for alternative sources of energy innovation with the concept of zero waste and the fuel potential from extractable petroleum hydrocarbons biodegradation waste, so it was necessary to study the use of extractable petroleum hydrocarbons biodegradation waste as the main material for making solid fuel. In addition, sawdust is a waste that had a great quantities and also had a high calorific value to be mixed with extractable petroleum hydrocarbons biodegradation waste. The purpose of this study was to determine the characteristics of the extractable petroleum hydrocarbons biodegradation waste and to determine the potential and a combination of a mixture of extractable petroleum hydrocarbons biodegradation waste and sawdust which has the best calorific value. The variables of this study was the composition of the waste and sawdust as follows 1:1; 1:3; and 3:1 (mass of sawdust : mass of waste) and time of sawdust carbonization was 10, 15 and 20 minutes. Sawdust was carbonized to get the high heating value. The characteristic of main material and fuel analysis performed with proximate analysis. While the calorific value analysis was performed with a bomb calorimeter. From the research, it was known that extractable petroleum hydrocarbons biodegradation waste had a moisture content of 3.06%; volatile matter 19.98%; ash content of 0.56%; fixed carbon content of 76.4% and a calorific value of 717 cal/gram. And a mixture that had the highest calorific value (4286.5 cal/gram) achieved in comparison sawdust : waste (3:1) by carbonization of sawdust for 20 minutes.

[Building Process and Architectural Planning Characteristics of Daehan Hospital Main Building].

PubMed

Lee, Geauchul

2016-04-01

This paper explores the introduction process of Daehan Hospital from Japan as the modern medical facility in Korea, and the architectural planning characteristics as a medical facility through the detailed building process of Daehan Hospital main building. The most noticeable characteristic of Daehan Hospital is that it was designed and constructed not by Korean engineers but by Japanese engineers. Therefore, Daehan Hospital was influenced by Japanese early modern medical facility, and Japanese engineers modeled Daehan Hospital main building on Tokyo Medical School main building which was constructed in 1876 as the first national medical school and hospital. The architectural type of Tokyo Medical School main building was a typical school architecture in early Japanese modern period which had a middle corridor and a pseudo Western-style tower, but Tokyo Medical School main building became the model of a medical facility as the symbol of the medical department in Tokyo Imperial University. This was the introduction and transplantation process of Japanese modern 'model' like as other modern systems and technologies during the Korean modern transition period. However, unlike Tokyo Medical School main building, Daehan Hospital main building was constructed not as a wooden building but as a masonry building. Comparing with the function of Daehan Hospital main building, its architectural form and construction costs was excessive scale, which was because Japanese Resident-General of Korea had the intention of ostentation that Japanese modernity was superior to Korean Empire.

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction.

PubMed

Papantoniou, Panagiotis

2018-04-03

The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures. For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures. Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance. The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.

Effect of calcination temperature of a copper ferrite synthesized by a sol-gel method on its structural characteristics and performance as Fenton catalyst to remove gallic acid from water.

PubMed

López-Ramón, María V; Álvarez, Miguel A; Moreno-Castilla, Carlos; Fontecha-Cámara, María A; Yebra-Rodríguez, África; Bailón-García, Esther

2018-02-01

A copper ferrite synthesized by a sol-gel combustion method was calcined at different temperatures up to 800°C, determining changes in its structural characteristics and magnetic measurements and studying its catalytic performance in gallic acid removal by Fenton reaction. The main objective was to study the effect of the calcination temperature of copper ferrite on its crystalline phase formation and transformation, activity and metal ion leaching. The cubic-to-tetragonal transformation of the spinel occurred via its reaction with the CuO phase, displacing Fe 3+ ions in B (octahedral) sites out of the spinel structure by the following reaction: 2Fe 3+ B +3CuO→Fe 2 O 3 +3Cu 2+ B . The catalysts showed superparamagnetic or substantial superparamagnetic behaviour. At higher calcination temperatures, catalyst activity was lower, and Cu ion leaching was markedly decreased. There was no Fe ion leaching with any catalyst. The as-prepared catalyst showed better catalytic performance than a commercial copper ferrite. Leached Cu ions acted as homogeneous catalysts, and their contribution to the overall removal mechanism was examined. Cu 2 O present in the as-prepared catalysts made only a small contribution to their activity. Finally, the reutilization of various catalysts was studied by performing different catalytic cycles. Copyright © 2017 Elsevier Inc. All rights reserved.

Seeing with sound? exploring different characteristics of a visual-to-auditory sensory substitution device.

PubMed

Brown, David; Macpherson, Tom; Ward, Jamie

2011-01-01

Sensory substitution devices convert live visual images into auditory signals, for example with a web camera (to record the images), a computer (to perform the conversion) and headphones (to listen to the sounds). In a series of three experiments, the performance of one such device ('The vOICe') was assessed under various conditions on blindfolded sighted participants. The main task that we used involved identifying and locating objects placed on a table by holding a webcam (like a flashlight) or wearing it on the head (like a miner's light). Identifying objects on a table was easier with a hand-held device, but locating the objects was easier with a head-mounted device. Brightness converted into loudness was less effective than the reverse contrast (dark being loud), suggesting that performance under these conditions (natural indoor lighting, novice users) is related more to the properties of the auditory signal (ie the amount of noise in it) than the cross-modal association between loudness and brightness. Individual differences in musical memory (detecting pitch changes in two sequences of notes) was related to the time taken to identify or recognise objects, but individual differences in self-reported vividness of visual imagery did not reliably predict performance across the experiments. In general, the results suggest that the auditory characteristics of the device may be more important for initial learning than visual associations.

Helicopter noise in hover: Computational modelling and experimental validation

NASA Astrophysics Data System (ADS)

Kopiev, V. F.; Zaytsev, M. Yu.; Vorontsov, V. I.; Karabasov, S. A.; Anikin, V. A.

2017-11-01

The aeroacoustic characteristics of a helicopter rotor are calculated by a new method, to assess its applicability in assessing rotor performance in hovering. Direct solution of the Euler equations in a noninertial coordinate system is used to calculate the near-field flow around the spinning rotor. The far-field noise field is calculated by the Ffowcs Williams-Hawkings (FW-H) method using permeable control surfaces that include the blade. For a multiblade rotor, the signal obtained is duplicated and shifted in phase for each successive blade. By that means, the spectral characteristics of the far-field noise may be obtained. To determine the integral aerodynamic characteristics of the rotor, software is written to calculate the thrust and torque characteristics from the near-field flow solution. The results of numerical simulation are compared with experimental acoustic and aerodynamic data for a large-scale model of a helicopter main rotor in an open test facility. Two- and four-blade configurations of the rotor are considered, in different hover conditions. The proposed method satisfactorily predicts the aerodynamic characteristics of the blades in such conditions and gives good estimates for the first harmonics of the noise. That permits the practical use of the proposed method, not only for hovering but also for forward flight.

Can individual health differences be explained by workplace characteristics?--A multilevel analysis.

PubMed

Marklund, Staffan; Bolin, Malin; von Essen, Jan

2008-02-01

Research on work-related health has mainly focused on individual factors. The present study expands the focus by exploring the role of organizational characteristics of workplaces for different individual health outcomes. The aim of the study was to look at differences in relative effect of workplace variations on five health outcomes, and to explain those differences in health outcomes by organizational characteristics. The sample encompassed 90 workplaces in Sweden and about 4300 individuals employed within these workplaces. Measurement of the workplace characteristics was carried out independently of the measurement of the individual's working conditions and health. Organizational data were collected by interviews with local managers at participating workplaces, and individual data were obtained by means of a survey of the employees. The results showed that a significant proportion of the variance in sickness absence, work ability, general health, and musculoskeletal disorders was attributed to the workplace. Of eight tested organizational characteristics, customer adaptation, lean production, and performance control could explain some of this workplace variance. The results also showed that only one organizational effect remained significant when controlled for the individual confounder of age and gender. High customer adaptation is associated with higher sickness absence. This association is not mediated via differences in mental and physical job strain.

Calculation of gas turbine characteristic

NASA Astrophysics Data System (ADS)

Mamaev, B. I.; Murashko, V. L.

2016-04-01

The reasons and regularities of vapor flow and turbine parameter variation depending on the total pressure drop rate π* and rotor rotation frequency n are studied, as exemplified by a two-stage compressor turbine of a power-generating gas turbine installation. The turbine characteristic is calculated in a wide range of mode parameters using the method in which analytical dependences provide high accuracy for the calculated flow output angle and different types of gas dynamic losses are determined with account of the influence of blade row geometry, blade surface roughness, angles, compressibility, Reynolds number, and flow turbulence. The method provides satisfactory agreement of results of calculation and turbine testing. In the design mode, the operation conditions for the blade rows are favorable, the flow output velocities are close to the optimal ones, the angles of incidence are small, and the flow "choking" modes (with respect to consumption) in the rows are absent. High performance and a nearly axial flow behind the turbine are obtained. Reduction of the rotor rotation frequency and variation of the pressure drop change the flow parameters, the parameters of the stages and the turbine, as well as the form of the characteristic. In particular, for decreased n, nonmonotonic variation of the second stage reactivity with increasing π* is observed. It is demonstrated that the turbine characteristic is mainly determined by the influence of the angles of incidence and the velocity at the output of the rows on the losses and the flow output angle. The account of the growing flow output angle due to the positive angle of incidence for decreased rotation frequencies results in a considerable change of the characteristic: poorer performance, redistribution of the pressure drop at the stages, and change of reactivities, growth of the turbine capacity, and change of the angle and flow velocity behind the turbine.

Space Shuttle Main Engine performance analysis

NASA Technical Reports Server (NTRS)

Santi, L. Michael

1993-01-01

For a number of years, NASA has relied primarily upon periodically updated versions of Rocketdyne's power balance model (PBM) to provide space shuttle main engine (SSME) steady-state performance prediction. A recent computational study indicated that PBM predictions do not satisfy fundamental energy conservation principles. More recently, SSME test results provided by the Technology Test Bed (TTB) program have indicated significant discrepancies between PBM flow and temperature predictions and TTB observations. Results of these investigations have diminished confidence in the predictions provided by PBM, and motivated the development of new computational tools for supporting SSME performance analysis. A multivariate least squares regression algorithm was developed and implemented during this effort in order to efficiently characterize TTB data. This procedure, called the 'gains model,' was used to approximate the variation of SSME performance parameters such as flow rate, pressure, temperature, speed, and assorted hardware characteristics in terms of six assumed independent influences. These six influences were engine power level, mixture ratio, fuel inlet pressure and temperature, and oxidizer inlet pressure and temperature. A BFGS optimization algorithm provided the base procedure for determining regression coefficients for both linear and full quadratic approximations of parameter variation. Statistical information relative to data deviation from regression derived relations was also computed. A new strategy for integrating test data with theoretical performance prediction was also investigated. The current integration procedure employed by PBM treats test data as pristine and adjusts hardware characteristics in a heuristic manner to achieve engine balance. Within PBM, this integration procedure is called 'data reduction.' By contrast, the new data integration procedure, termed 'reconciliation,' uses mathematical optimization techniques, and requires both measurement and balance uncertainty estimates. The reconciler attempts to select operational parameters that minimize the difference between theoretical prediction and observation. Selected values are further constrained to fall within measurement uncertainty limits and to satisfy fundamental physical relations (mass conservation, energy conservation, pressure drop relations, etc.) within uncertainty estimates for all SSME subsystems. The parameter selection problem described above is a traditional nonlinear programming problem. The reconciler employs a mixed penalty method to determine optimum values of SSME operating parameters associated with this problem formulation.

[Rationality of commodity criteria and traditional breeding of Polygala tenuifolia based on agronomic traits and determination of chemical components].

PubMed

Wang, Dan-Dan; Bai, Lu; Xu, Xiao-Shuang; Zhang, Fu-Sheng; Xing, Jie; Jia, Jin-Ping; Tian, Hong-Ling; Qin, Xue-Mei

2016-10-01

The agronomic traits (plant height, root diameter, root length, first lateral root height, lateral root amount, root weight) of 18 Polygala tenuifolia samples with different agronomic traits were analyzed, respectively. HPLC was used to analyze three main characteristic components including tenuifolin, polygalaxanthone Ⅲ, and 3,6'-disinapoyl sucrose. At last, the correlation between six agronomic traits and three main characteristic components were analyzed by scatter plot. We found no significant correlation between root diameter and three main characteristic components. There were no obvious correlations between tenuifolin and the remaining five agronomic traits. Short root length and first lateral root height as well as high lateral root amount resulted in high levels of polygalaxanthone Ⅲ in P. tenuifolia samples. High levels of 3,6'-disinapoyl sucrose were observed in P. tenuifolia samples with longer root. So, the current commodity criteria and traditional breeding of P. tenuifolia did not conform to pharmacopoeia standards, which excellent medicinal materials should have high contents of the main characteristic components. It was urgent to revise the current commodity criteria and breeding methods. Copyright© by the Chinese Pharmaceutical Association.

Influence of sintering temperature on the phases and photoelectric characteristics of BiOCl/ZnO composite powders

NASA Astrophysics Data System (ADS)

Chen, Song; Zhu, De-gui

2017-12-01

Zinc oxide is a typical functional oxide that has been widely researched for various industry applications due to its peculiar physical characteristics. However, to achieve its potential in promising applications, much work has been diligently performed to improve the physical properties of ZnO. In this work, an aqueous suspension route was used to prepare BiOCl/ZnO composite powders, and sintering processes were applied to investigate the influence of sintering temperature on the phase evolutions, microstructures, and photoelectric characteristics of BiOCl/ZnO composite powders. The results indicated that the photoelectric properties mainly depend on the relevant content of BiOCl in the composite powders and the sintering temperature. The photoelectric measurements in K2SO4 solutions show that the photoelectric properties of the samples with the appropriate BiOCl content (0.3mol% and 2.0mol%) are better than those of ZnO and commercial TiO2 (P25) powders, but the photoelectric measurements in NaOH solutions indicate that the photoelectric characteristics of the as-sintered samples are only better than those of P25.

Research on the laser transmission characteristics simulation and comprehensive test in complex channel environment

NASA Astrophysics Data System (ADS)

Fu, Qiang; Liu, Jianhua; Wang, Xiaoman; Jiang, Huilin; Liu, Zhi

2014-12-01

The laser transmission characteristics affected in the complex channel environment, which limits the performance of laser equipment and engineering application severely. The article aim at the influence of laser transmission in atmospheric and seawater channels, summarizes the foreign researching work of the simulation and comprehensive test regarding to the laser transmission characteristics in complex environment. And researched the theory of atmospheric turbulence effect, water attenuation features, and put forward the corresponding theoretical model. And researched the simulate technology of atmospheric channel and sea water channel, put forward the analog device plan, adopt the similar theory of flowing to simulate the atmosphere turbulence .When the flowing has the same condition of geometric limits including the same Reynolds, they must be similar to each other in the motivation despite of the difference in the size, speed, and intrinsic quality. On this basis, set up a device for complex channel simulation and comprehensive testing, the overall design of the structure of the device, Hot and Cold Air Convection Simulation of Atmospheric Turbulence, mainly consists of cell body, heating systems, cooling systems, automatic control system. he simulator provides platform and method for the basic research of laser transmission characteristics in the domestic.

Addressing Palliative Sedation during Expert Consultation: A Descriptive Analysis of the Practice of Dutch Palliative Care Consultation Teams

PubMed Central

Hoek, Patrick; Grandjean, Ilse; Verhagen, Constans A. H. H. V. M.; Jansen-Landheer, Marlies L. E. A.; Schers, Henk J.; Galesloot, Cilia; Vissers, Kris C. P.; Engels, Yvonne; Hasselaar, Jeroen G.J.

2015-01-01

Main Objective Since palliative sedation is considered a complex intervention, consultation teams are increasingly established to support general practice. This study aims to offer insight into the frequency and characteristics of expert consultations regarding palliative sedation. Methods We performed a retrospective analysis of a longitudinal database. This database contained all patient-related consultations by Dutch Palliative Care Consultation teams, that were requested between 2004 and 2011. We described the frequency and characteristics of these consultations, in particular of the subgroup of consultations in which palliative sedation was addressed (i.e. PSa consultations). We used multivariate regression analysis to explore consultation characteristics associated with a higher likelihood of PSa consultations. Main Results and Their Significance Of the 44,443 initial consultations, most were requested by general practitioners (73%) and most concerned patients with cancer (86%). Palliative sedation was addressed in 18.1% of all consultations. Palliative sedation was relatively more often discussed during consultations for patients with a neurologic disease (OR 1.79; 95% CI: 1.51–2.12) or COPD (OR 1.39; 95% CI: 1.15–1.69) than for patients with cancer. We observed a higher likelihood of PSa consultations if the following topics were also addressed during consultation: dyspnoea (OR 1.30; 95% CI: 1.22–1.40), agitation/delirium (OR 1.57; 95% CI: 1.47–1.68), exhaustion (OR 2.89; 95% CI: 2.61–3.20), euthanasia-related questions (OR 2.65; 95% CI: 2.37–2.96) or existential issues (OR 1.55; 95% CI: 1.31–1.83). Conclusion In conclusion, PSa consultations accounted for almost one-fifth of all expert consultations and were associated with several case-related characteristics. These characteristics may help clinicians in identifying patients at risk for a more complex disease trajectory at the end of life. PMID:26301746

Market Conditions and Performance in the Nursing Home Compare Five-Star Rating.

PubMed

Kim, Ae-Sook

2016-10-01

Previous studies have documented that market conditions affect nursing home performance; however, the evidence is inconsistent and conflicting. This study introduces three groups of county market conditions and a peer effect variable, and tests their impacts on the Nursing Home Compare (NHC) Five-Star overall rating. Indiana nursing home data and county characteristics are taken mainly from the NHC and Census Bureau websites. The result of the ordered logistic regression analysis indicates that nursing homes in excess demand markets, namely those that are highly concentrated and have fewer nursing homes, tend to perform better than their counterparts in both excess supply and balanced markets. In addition, a peer effect variable, measured as the average overall rating of the competitors, promotes performance improvement. These findings imply that small markets enable consumers to be well informed about a provider's reputation for quality, consequently enhancing performance. Furthermore, not only consumers but also providers seem to seek performance information on the report card to understand their relative position in the market, which thus affects their market strategies and subsequently performance. Copyright © 2016 by Duke University Press.

Live performance, carcass characteristic and blood metabolite responses of broilers to two distinct corn types with different extent of grinding.

PubMed

Zhao, J P; Cui, D P; Zhang, Z Y; Jiao, H C; Song, Z G; Lin, H

2017-04-01

The major objective of this research was to establish the main and interactive effects of corn type and extent of grinding on broiler performance including carcass characteristics. A completely randomized experimental design with a 2 (corn type) × 2 (fine and coarse) factorial arrangement, each with six replicates of 45 male Ross chicks, was applied. Experimental diets, containing dent or hard corn, were formulated with two extents of grinding (3.00 or 6.00 mm screens) for three growing phases. In comparison with dent corn, the hard corn increased body weight (BW) gain and thigh muscle yield (p < 0.05), while decreasing feed conversion ratio (p < 0.01) and abdominal fat deposition (p < 0.05), some aspects of which were age-dependent and appeared to vary with extent of grinding. Coarser grinding increased the weight of proventriculus (p < 0.01), gizzard (p < 0.05) and small + large intestine (p < 0.10) relative to BW, particularly towards market size. These results suggest that feeding hard corn or large-particle-size corn have some favourable effects on growth performance or gastrointestinal development for finishing broilers. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Prediction of flow duration curves for ungauged basins

NASA Astrophysics Data System (ADS)

Atieh, Maya; Taylor, Graham; M. A. Sattar, Ahmed; Gharabaghi, Bahram

2017-02-01

This study presents novel models for prediction of flow Duration Curves (FDCs) at ungauged basins using artificial neural networks (ANN) and Gene Expression Programming (GEP) trained and tested using historical flow records from 171 unregulated and 89 regulated basins across North America. For the 89 regulated basins, FDCs were generated for both before and after flow regulation. Topographic, climatic, and land use characteristics are used to develop relationships between these basin characteristics and FDC statistical distribution parameters: mean (m) and variance (ν). The two main hypotheses that flow regulation has negligible effect on the mean (m) while it the variance (ν) were confirmed. The novel GEP model that predicts the mean (GEP-m) performed very well with high R2 (0.9) and D (0.95) values and low RAE value of 0.25. The simple regression model that predicts the variance (REG-v) was developed as a function of the mean (m) and a flow regulation index (R). The measured performance and uncertainty analysis indicated that the ANN-m was the best performing model with R2 (0.97), RAE (0.21), D (0.93) and the lowest 95% confidence prediction error interval (+0.22 to +3.49). Both GEP and ANN models were most sensitive to drainage area followed by mean annual precipitation, apportionment entropy disorder index, and shape factor.

Characteristics and Challenges of Open-Water Swimming Performance: A Review.

PubMed

Baldassarre, Roberto; Bonifazi, Marco; Zamparo, Paola; Piacentini, Maria Francesca

2017-11-01

Although the popularity of open-water swimming (OWS) events has significantly increased in the last decades, specific studies regarding performance of elite or age-group athletes in these events are scarce. To analyze the existing literature on OWS. Relevant literature was located via computer-generated citations. During August 2016, online computer searches on PubMed and Scopus databases were conducted to locate published research. The number of participants in ultraendurance swimming events has substantially increased in the last 10 y. In elite athletes there is a higher overall competitive level of women than of men. The body composition of female athletes (different percentage and distribution of fat tissue) shows several advantages (more buoyancy and less drag) in aquatic conditions that determine the small difference between males and females. The main physiological characteristics of open-water swimmers (OW swimmers) are the ability to swim at high percentage of [Formula: see text] (80-90%) for many hours. Furthermore, to sustain high velocity for many hours, endurance swimmers need a high propelling efficiency and a low energy cost. Open-water races may be characterized by extreme environmental conditions (water temperature, tides, currents, and waves) that have an overall impact on performance, influencing tactics and pacing. Future studies are needed to study OWS in both training and competition.

Absolute and convective instabilities of a film flow down a vertical fiber subjected to a radial electric field

NASA Astrophysics Data System (ADS)

Liu, Rong; Chen, Xue; Ding, Zijing

2018-01-01

We consider the motion of a gravity-driven flow down a vertical fiber subjected to a radial electric field. This flow exhibits rich dynamics including the formation of droplets, or beads, driven by a Rayleigh-Plateau mechanism modified by the presence of gravity as well as the Maxwell stress at the interface. A spatiotemporal stability analysis is performed to investigate the effect of electric field on the absolute-convective instability (AI-CI) characteristics. We performed a numerical simulation on the nonlinear evolution of the film to examine the transition from CI to AI regime. The numerical results are in excellent agreement with the spatiotemporal stability analysis. The blowup behavior of nonlinear simulation predicts the formation of touchdown singularity of the interface due to the effect of electric field. We try to connect the blowup behavior with the AI-CI characteristics. It is found that the singularities mainly occur in the AI regime. The results indicate that the film may have a tendency to form very sharp tips due to the enhancement of the absolute instability induced by the electric field. We perform a theoretical analysis to study the behaviors of the singularities. The results show that there exists a self-similarity between the temporal and spatial distances from the singularities.

Characteristics of individuals receiving disability benefits in the Netherlands and predictors of leaving the disability benefit scheme: a retrospective cohort study with five-year follow-up.

PubMed

Louwerse, Ilse; Huysmans, Maaike A; van Rijssen, H Jolanda; van der Beek, Allard J; Anema, Johannes R

2018-01-18

Today, work disability is one of the greatest social and labour market challenges for policy makers in most OECD countries, where on average, about 6% of the working-age population relies on disability benefits. Understanding of factors associated with long-term work disability may be helpful to identify groups of individuals at risk for disability benefit entitlement or continuing eligibility, and to develop effective interventions for these groups. The purpose of this study is to provide insight into the main diagnoses of workers who qualify for disability benefits and how these diagnoses differ in age, gender and education. Using a five-year follow-up, we examined the duration of disability benefits and how durations differ among individuals with various characteristics. We performed a cohort study of 31,733 individuals receiving disability benefits from the Dutch Social Security Institute (SSI) with a five-year follow-up. Data were collected from SSI databases. Information about disorders was assessed by an insurance physician upon benefit application. These data were used to test for significant relationships among socio-demographics, main diagnoses and comorbidity, and disability benefit entitlement and continuing eligibility. Mental disorders were the most frequent diagnosis for individuals claiming work disability. Diagnoses differed among age groups and education categories. Mental disorders were the main diagnosis for work disability for younger and more highly educated individuals, and physical disorders (generally musculoskeletal, cardiovascular and cancer) were the main diagnosis for older and less educated individuals. In 82% of the claims, the duration of disability benefit was five years or more after approval. Outflow was lowest for individuals with (multiple) mental disorders and those with comorbidity of mental and physical disorders, and highest for individuals with (multiple) physical disorders. The main diagnosis for persons entitled to disability benefits was mental health problems, especially for young women. In a five-year follow-up, claim duration for disability benefits was long lasting for most claimants.

High resolution flow field prediction for tail rotor aeroacoustics

NASA Technical Reports Server (NTRS)

Quackenbush, Todd R.; Bliss, Donald B.

1989-01-01

The prediction of tail rotor noise due to the impingement of the main rotor wake poses a significant challenge to current analysis methods in rotorcraft aeroacoustics. This paper describes the development of a new treatment of the tail rotor aerodynamic environment that permits highly accurate resolution of the incident flow field with modest computational effort relative to alternative models. The new approach incorporates an advanced full-span free wake model of the main rotor in a scheme which reconstructs high-resolution flow solutions from preliminary, computationally inexpensive simulations with coarse resolution. The heart of the approach is a novel method for using local velocity correction terms to capture the steep velocity gradients characteristic of the vortex-dominated incident flow. Sample calculations have been undertaken to examine the principal types of interactions between the tail rotor and the main rotor wake and to examine the performance of the new method. The results of these sample problems confirm the success of this approach in capturing the high-resolution flows necessary for analysis of rotor-wake/rotor interactions with dramatically reduced computational cost. Computations of radiated sound are also carried out that explore the role of various portions of the main rotor wake in generating tail rotor noise.

Performance of Electricity Generation from Bryophyllum Leaf for Practical Utilisation

NASA Astrophysics Data System (ADS)

Khan, Md. Kamrul Alam

2017-01-01

Constructing an affordable cost, environment friendly simplified electrical energy source with Pathor Kuchi Leaf (PKL) for power electrifications which will significantly upgrade the life style of 1.6 billion people especially, who live in rural areas of Bangladesh. However, one fifth of the world's population still lack access to electricity-well, mainly in Sub-Saharan Africa and South Asia (Bangladesh, India, Sri Lanka, Pakistan, Nepal and Bhutan). This innovative technology will meet essential requirements as lighting, telecommunication as well as information access. Electrodes are put into the Bryophyllum Pinnatum Leaf (BPL) or Pathor Kuchi Leaf (PKL) sap and they produce substantially sufficient amount of electricity to power energy consumed electronics and electrical appliances. CuSO4.5H2O solution is used as a secondary salt. The role of CuSO4.5H2O solution has been studied. The electrical and chemical properties, a very important factor for PKL electricity generation device have been studied in this research work. The electrical properties are: internal resistance, voltage regulation, energy efficiency, pulse performance, self discharge characteristics, discharge characteristics with load, capacity of the PKL cell, temperature characteristics and life cycle of the PKL cell. The chemical properties are: variation of voltage, current with the variation of [Zn2+], [Cu2+] and time. The performance of the production of the two bi-products (fertilizer and hydrogen gas production) has been studied. Variation of concentration of Zn2+ and Cu2+ with the variation of percentage of the I am grateful to the authority of the Science and technology ministry,Bangladesh for financial support during the research work.

Effects of friction layer characteristics on the tribological properties of Ni3Al solid-lubricating composites at different load conditions

NASA Astrophysics Data System (ADS)

Lu, Guanchen; Shi, Xiaoliang; Huang, Yuchun; Liu, Xiyao; Yang, Meijun

2018-05-01

This paper investigates the effects of friction layer characteristics of Ni3Al matrix self-lubricating composites (NMCs) on the tribological properties sliding against ceramic ball Si3N4 at dry friction process at the different load conditions. The characteristics of friction layer are performed in terms of hardness of wear scars, thickness and elemental distributions of friction layer. The results show that the microhardness of wear scars of NMCs increases with the increase of the sliding time and applied load, which results in friction coefficient reduced and wear rate decreased, indicating that the tribological performance of NMCs is obviously affected by microhardness of wear scar. However, under excessive applied load, the performance of friction layer of NMCs is deteriorated for the spalling of wear debris and deformation of contact surface. Therefore, selecting appropriate load conditions during the sliding contact, at the transition to the optimal properties of friction layer maybe occur. NMCs exhibits excellent tribological properties at 15N, which leads to the lowest friction coefficient (0.386) and wear rate (2.48 × 10‑5 mm3 N‑1 m‑1), as well as the smoothest surface of wear track compared with the other load conditions. Meanwhile, the elemental distributions analysis of cross-section of friction layer of NMCs shows that the frictional structures can be divided into three main layers. The thickness of the friction-affected layer varies with the changing of applied load. These results could provide a reference for preparing the solid-lubrication materials with better tribological properties.

On the practice of ignoring center-patient interactions in evaluating hospital performance.

PubMed

Varewyck, Machteld; Vansteelandt, Stijn; Eriksson, Marie; Goetghebeur, Els

2016-01-30

We evaluate the performance of medical centers based on a continuous or binary patient outcome (e.g., 30-day mortality). Common practice adjusts for differences in patient mix through outcome regression models, which include patient-specific baseline covariates (e.g., age and disease stage) besides center effects. Because a large number of centers may need to be evaluated, the typical model postulates that the effect of a center on outcome is constant over patient characteristics. This may be violated, for example, when some centers are specialized in children or geriatric patients. Including interactions between certain patient characteristics and the many fixed center effects in the model increases the risk for overfitting, however, and could imply a loss of power for detecting centers with deviating mortality. Therefore, we assess how the common practice of ignoring such interactions impacts the bias and precision of directly and indirectly standardized risks. The reassuring conclusion is that the common practice of working with the main effects of a center has minor impact on hospital evaluation, unless some centers actually perform substantially better on a specific group of patients and there is strong confounding through the corresponding patient characteristic. The bias is then driven by an interplay of the relative center size, the overlap between covariate distributions, and the magnitude of the interaction effect. Interestingly, the bias on indirectly standardized risks is smaller than on directly standardized risks. We illustrate our findings by simulation and in an analysis of 30-day mortality on Riksstroke. © 2015 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

Is intracytoplasmic morphologically selected sperm injection (IMSI) beneficial in the first ART cycle? a multicentric randomized controlled trial.

PubMed

Leandri, R D; Gachet, A; Pfeffer, J; Celebi, C; Rives, N; Carre-Pigeon, F; Kulski, O; Mitchell, V; Parinaud, J

2013-09-01

Intracytoplasmic morphologically selected sperm injection (IMSI), by selecting spermatozoa at high magnification improves the outcome of intracytoplasmic sperm injection (ICSI) mainly after several failures. However, only few monocentric randomized studies are available and they do not analyse results as a function of sperm characteristics. In 255 couples attempting their first assisted reproductive technology (ART) attempt for male infertility (motile sperm count <1×10⁶ after sperm selection, but at least 3×10⁶ spermatozoa per ejaculate to allow a detailed analysis of sperm characteristics), a prospective randomized trial was performed to compare the clinical outcomes of IMSI and ICSI and to evaluate the influence of sperm characteristics on these outcomes. IMSI did not provide any significant improvement in the clinical outcomes compared with ICSI neither for implantation (24% vs. 23%), nor clinical pregnancy (31% vs. 33%) nor live birth rates (27% vs. 30%). Moreover, the results of IMSI were similar to the ICSI ones whatever the degree of sperm DNA fragmentation, nuclear immaturity and sperm morphology. These results show that IMSI instead of ICSI has no advantage in the first ART attempts. However, this does not rule out IMSI completely and more randomized trials must be performed especially regarding patients carrying severe teratozoospermia, or high sperm DNA fragmentation levels or having previous ICSI failures. © 2013 American Society of Andrology and European Academy of Andrology.

The effect of material characteristics of shoe soles on muscle activation and energy aspects during running.

PubMed

Nigg, B M; Stefanyshyn, D; Cole, G; Stergiou, P; Miller, J

2003-04-01

The purposes of this study were (a) to determine group and individual differences in oxygen consumption during heel-toe running and (b) to quantify the differences in EMG activity for selected muscle groups of the lower extremities when running in shoes with different mechanical heel characteristics. Twenty male runners performed heel-toe running using two shoe conditions, one with a mainly elastic and a visco-elastic heel. Oxygen consumption was quantified during steady state runs of 6 min duration, running slightly above the aerobic threshold providing four pairs of oxygen consumption results for comparison. Muscle activity was quantified using bipolar surface EMG measurements from the tibialis anterior, medial gastrocnemius, vastus medialis and the hamstrings muscle groups. EMG data were sampled for 5 s every minute for the 6 min providing 30 trials. EMG data were compared for the different conditions using an ANOVA (alpha=0.05). The findings of this study showed that changes in the heel material characteristics of running shoes were associated with (a) subject specific changes in oxygen consumption and (b) subject and muscle specific changes in the intensities of muscle activation before heel strike in the lower extremities. It is suggested that further study of these phenomena will help understand many aspects of human locomotion, including work, performance, fatigue and possible injuries.

Riparian forest and instream large wood characteristics, West Branch Sheepscot River, Maine, USA

Treesearch

Melissa Laser; James Jordan; Keith Nislow

2009-01-01

This study examined riparian forest and instream large wood characteristics in a 2.7 km reach of the West Branch of the Sheepscot River in Maine in order to increase our basic knowledge of these components in a system that is known to have undergone multiple land conversion. The West Branch is approximately 40 km long, drains a 132 km2...

Characteristics of suspended and streambed sediment within constructed chutes and the main channel at Upper Hamburg and Glovers Point Bends, Missouri River, Nebraska, 2008

USGS Publications Warehouse

Woodward, Brenda K.; Rus, David L.

2011-01-01

The U.S. Army Corps of Engineers, Omaha District, as part of the Missouri River Bank Stabilization and Navigation Mitigation Project, has constructed 17 off-channel chutes along the channelized Missouri River, downstream from Sioux City, Iowa, to increase habitat diversity. To better understand characteristics of suspended and streambed sediment within these constructed chutes, the U.S. Geological Survey investigated specific aspects of chute design and function in relation to sediment characteristics including: (1) effects of inlet structures; (2) changes occurring between the inlet and the outlet of a chute; (3) effects of chutes on sediment characteristics in the main channel; and (4) differences in chute dynamics between sampled chutes. Two chutes differing in design, location, and dynamics were studied, Upper Hamburg Bend near Nebraska City, Nebr., and Glovers Point Bend near Winnebago, Nebr. Each site was characterized using five or more sampling transects (two in the chute and three to four in the main channel) designed to bracket sediment exchanges between chutes and the main channel. A sixth transect was included at the Upper Hamburg Bend study site to account for the effects of a nontarget chute having its inlet midway between the inlet and outlet of the primary chute. Representative samples of suspended and streambed sediment were collected at each transect, along with measurements of turbidity and streamflow, between June and November 2008. Four sets of samples were collected at the Glovers Point Bend study site and five sample sets were collected from the Upper Hamburg Bend study site. Results from paired t-tests and standard t-tests indicated that the inlet structure design, passing inflow only from the top of the main-channel water column, reduced the supply of coarse-grained suspended sediment entering the chutes. Statistical comparisons did not indicate differences between the inlet and outlet of either chute; however, anecdotal evidence of recent bank erosion and in-channel deposition was observed in both chutes during the study period. Chutes had little effect on Missouri River main-channel sediment characteristics, which could be explained by the much greater streamflow of the main channel. Between-chute comparisons showed no significant differences in the suspended-sediment characteristics; however, the Upper Hamburg Bend chute had a coarser streambed, wider channel, and much greater streamflow than did the Glovers Point Bend chute.

Irreversible and endoreversible behaviors of the LD-model for heat devices: the role of the time constraints and symmetries on the performance at maximum χ figure of merit

NASA Astrophysics Data System (ADS)

Gonzalez-Ayala, Julian; Calvo Hernández, A.; Roco, J. M. M.

2016-07-01

The main unified energetic properties of low dissipation heat engines and refrigerator engines allow for both endoreversible or irreversible configurations. This is accomplished by means of the constraints imposed on the characteristic global operation time or the contact times between the working system with the external heat baths and modulated by the dissipation symmetries. A suited unified figure of merit (which becomes power output for heat engines) is analyzed and the influence of the symmetries on the optimum performance discussed. The obtained results, independent on any heat transfer law, are faced with those obtained from Carnot-like heat models where specific heat transfer laws are needed. Thus, it is shown that only the inverse phenomenological law, often used in linear irreversible thermodynamics, correctly reproduces all optimized values for both the efficiency and coefficient of performance values.

Protocol Support for a New Satellite-Based Airspace Communication Network

NASA Technical Reports Server (NTRS)

Shang, Yadong; Hadjitheodosiou, Michael; Baras, John

2004-01-01

We recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the characteristics of an aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. We discuss various extensions to standard TCP that alleviate some of these performance problems. Through simulation, we identify those TCP implementations that can be expected to perform well. Based on the observation that it is difficult for an end-to-end solution to solve these problems effectively, we propose a new TCP-splitting protocol, termed Aeronautical Transport Control Protocol (AeroTCP). The main idea of this protocol is to use a fixed window for flow control and one duplicated acknowledgement (ACK) for fast recovery. Our simulation results show that AeroTCP can maintain higher utilization for the satellite link than end-to-end TCP, especially in high BER environment.

Performance assessment of geospatial simulation models of land-use change--a landscape metric-based approach.

PubMed

Sakieh, Yousef; Salmanmahiny, Abdolrassoul

2016-03-01

Performance evaluation is a critical step when developing land-use and cover change (LUCC) models. The present study proposes a spatially explicit model performance evaluation method, adopting a landscape metric-based approach. To quantify GEOMOD model performance, a set of composition- and configuration-based landscape metrics including number of patches, edge density, mean Euclidean nearest neighbor distance, largest patch index, class area, landscape shape index, and splitting index were employed. The model takes advantage of three decision rules including neighborhood effect, persistence of change direction, and urbanization suitability values. According to the results, while class area, largest patch index, and splitting indices demonstrated insignificant differences between spatial pattern of ground truth and simulated layers, there was a considerable inconsistency between simulation results and real dataset in terms of the remaining metrics. Specifically, simulation outputs were simplistic and the model tended to underestimate number of developed patches by producing a more compact landscape. Landscape-metric-based performance evaluation produces more detailed information (compared to conventional indices such as the Kappa index and overall accuracy) on the model's behavior in replicating spatial heterogeneity features of a landscape such as frequency, fragmentation, isolation, and density. Finally, as the main characteristic of the proposed method, landscape metrics employ the maximum potential of observed and simulated layers for a performance evaluation procedure, provide a basis for more robust interpretation of a calibration process, and also deepen modeler insight into the main strengths and pitfalls of a specific land-use change model when simulating a spatiotemporal phenomenon.

Force generation and wing deformation characteristics of a flapping-wing micro air vehicle 'DelFly II' in hovering flight.

PubMed

Percin, M; van Oudheusden, B W; de Croon, G C H E; Remes, B

2016-05-19

The study investigates the aerodynamic performance and the relation between wing deformation and unsteady force generation of a flapping-wing micro air vehicle in hovering flight configuration. Different experiments were performed where fluid forces were acquired with a force sensor, while the three-dimensional wing deformation was measured with a stereo-vision system. In these measurements, time-resolved power consumption and flapping-wing kinematics were also obtained under both in-air and in-vacuum conditions. Comparison of the results for different flapping frequencies reveals different wing kinematics and deformation characteristics. The high flapping frequency case produces higher forces throughout the complete flapping cycle. Moreover, a phase difference occurs in the variation of the forces, such that the low flapping frequency case precedes the high frequency case. A similar phase lag is observed in the temporal evolution of the wing deformation characteristics, suggesting that there is a direct link between the two phenomena. A considerable camber formation occurs during stroke reversals, which is mainly determined by the stiffener orientation. The wing with the thinner surface membrane displays very similar characteristics to the baseline wing, which implies the dominance of the stiffeners in terms of providing rigidity to the wing. Wing span has a significant effect on the aerodynamic efficiency such that increasing the span length by 4 cm results in a 6% enhancement in the cycle-averaged X-force to power consumption ratio compared to the standard DelFly II wings with a span length of 28 cm.

Modeling of mid-infrared quantum cascade lasers: The role of temperature and operating field strength on the laser performance

NASA Astrophysics Data System (ADS)

Yousefvand, Hossein Reza

2017-07-01

In this paper a self-consistent numerical approach to study the temperature and bias dependent characteristics of mid-infrared (mid-IR) quantum cascade lasers (QCLs) is presented which integrates a number of quantum mechanical models. The field-dependent laser parameters including the nonradiative scattering times, the detuning and energy levels, the escape activation energy, the backfilling excitation energy and dipole moment of the optical transition are calculated for a wide range of applied electric fields by a self-consistent solution of Schrodinger-Poisson equations. A detailed analysis of performance of the obtained structure is carried out within a self-consistent solution of the subband population rate equations coupled with carrier coherent transport equations through the sequential resonant tunneling, by taking into account the temperature and bias dependency of the relevant parameters. Furthermore, the heat transfer equation is included in order to calculate the carrier temperature inside the active region levels. This leads to a compact predictive model to analyze the temperature and electric field dependent characteristics of the mid-IR QCLs such as the light-current (L-I), electric field-current (F-I) and core temperature-electric field (T-F) curves. For a typical mid-IR QCL, a good agreement was found between the simulated temperature-dependent L-I characteristic and experimental data, which confirms validity of the model. It is found that the main characteristics of the device such as output power and turn-on delay time are degraded by interplay between the temperature and Stark effects.

Sex differences in left main coronary artery stenting: Different characteristics but similar outcomes for women compared with men.

PubMed

Shin, Eun-Seok; Lee, Cheol Whan; Ahn, Jung-Min; Lee, Pil Hyung; Chang, Mineok; Kim, Min-Ju; Yoon, Sung-Han; Park, Duk-Woo; Kang, Soo-Jin; Lee, Seung-Whan; Kim, Young-Hak; Park, Seong-Wook; Park, Seung-Jung

2018-02-15

The clinical outcomes for women compared with men undergoing left main PCI were sparse. We compared the characteristics and long-term outcomes in women versus men after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for unprotected left main CAD. We identified 2328 patients (545 women; 1783 men) with unprotected left main CAD who received PCI with DES between January 2007 and December 2013 in the Interventional Cardiology Research In-cooperation Society-left MAIN revascularization (IRIS-MAIN) registry. The primary outcome was a composite of death from any cause, myocardial infarction, or stroke. The median follow-up time was 2.9years (interquartile range: 1.0-4.1years). Women were older, had a higher incidence of insulin-requiring diabetes mellitus and hypertension, and more commonly presented with acute coronary syndrome than men. Left main ostial lesion was more common in women, whereas left main bifurcation lesion with more extensive CAD was more common in men. The incidence of primary outcome was similar between the two groups (10.8% vs. 10.8%, respectively, log-rank p=0.587). The results were similar after adjustment for baseline variables and consistent across major subgroups. The need for target lesion revascularization was significantly higher in women than in men (8.8% vs. 5.7%, respectively, p<0.05) but the sex bias was not confirmed after adjusting for confounders. Women, as compared to men, had different clinical and lesion characteristics but similar long-term outcomes after PCI with DES for left main CAD. Copyright © 2017 Elsevier B.V. All rights reserved.

Galileo IOV Electrical Power Subsystem Relies On Li-Ion Batter Charge Management Controlled By Hardware

NASA Astrophysics Data System (ADS)

Douay, N.

2011-10-01

In the frame of GALILEO In-Orbit Validation program which is composed of 4 satellites, Thales Alenia Space France has designed, developed and tested the Electrical Power Subsystem. Besides some classical design choices like: -50V regulated main power bus provided by the PCDU manufactured by Terma (DK), -Solar array, manufactured by Dutch-Space (NL), using Ga-As triple junction technology from Azur Space Power Solar GmbH, -SAFT (FR) Lithium-ion Battery for which cell package balancing function is required, -Solar Array Drive Mechanism, provided by RUAG Space Switzerland, to transfer the power. This subsystem features a fully autonomous, failure tolerant, battery charge management able to operate even after a complete unavailability of the on-board software. The battery charge management is implemented such that priority is always given to satisfy the satellite main bus needs in order to maintain the main bus regulation under MEA control. This battery charge management principle provides very high reliability and operational robustness. So, the paper describes : -the battery charge management concept using a combination of PCDU hardware and relevant battery lines monitoring, -the functional aspect of the single point failure free S4R (Sequential Switching Shunt Switch Regulator) and associated performances, -the failure modes isolated and passivated by this architecture. The paper will address as well the autonomous balancing function characteristics and performances.

Understanding Water Storage Practices of Urban Residents of an Endemic Dengue Area in Colombia: Perceptions, Rationale and Socio-Demographic Characteristics.

PubMed

García-Betancourt, Tatiana; Higuera-Mendieta, Diana Rocío; González-Uribe, Catalina; Cortés, Sebastian; Quintero, Juliana

2015-01-01

The main preventive measure against dengue virus transmission is often based on actions to control Ae. Aegypti reproduction by targeting water containers of clean and stagnant water. Household water storage has received special attention in prevention strategies but the evidence about the rationale of this human practice is limited. The objective was to identify and describe water storage practices among residents of an urban area in Colombia (Girardot) and its association with reported perceptions, rationales and socio-demographic characteristics with a mixed methods approach. Knowledge, attitudes and practices and entomological surveys from 1,721 households and 26 semi-structured interviews were conducted among residents of Girardot and technicians of the local vector borne disease program. A multivariate analysis was performed to identify associations between a water storage practice and socio-demographic characteristics, and knowledge, attitudes and practices about dengue and immature forms of the vector, which were then triangulated with qualitative information. Water storage is a cultural practice in Girardot. There are two main reasons for storage: The scarcity concern based on a long history of shortages of water in the region and the perception of high prices in water rates, contrary to what was reported by the local water company. The practice of water storage was associated with being a housewife (Inverse OR: 2.6, 95% CI 1.5 -4.3). The use of stored water depends on the type of container used, while water stored in alberca (Intra household cement basins) is mainly used for domestic cleaning chores, water in plastic containers is used for cooking. It is essential to understand social practices that can increase or reduce the number of breeding sites of Ae. Aegypti. Identification of individuals who store water and the rationale of such storage allow a better understanding of the social dynamics that lead to water accumulation.

VALUE - Validating and Integrating Downscaling Methods for Climate Change Research

NASA Astrophysics Data System (ADS)

Maraun, Douglas; Widmann, Martin; Benestad, Rasmus; Kotlarski, Sven; Huth, Radan; Hertig, Elke; Wibig, Joanna; Gutierrez, Jose

2013-04-01

Our understanding of global climate change is mainly based on General Circulation Models (GCMs) with a relatively coarse resolution. Since climate change impacts are mainly experienced on regional scales, high-resolution climate change scenarios need to be derived from GCM simulations by downscaling. Several projects have been carried out over the last years to validate the performance of statistical and dynamical downscaling, yet several aspects have not been systematically addressed: variability on sub-daily, decadal and longer time-scales, extreme events, spatial variability and inter-variable relationships. Different downscaling approaches such as dynamical downscaling, statistical downscaling and bias correction approaches have not been systematically compared. Furthermore, collaboration between different communities, in particular regional climate modellers, statistical downscalers and statisticians has been limited. To address these gaps, the EU Cooperation in Science and Technology (COST) action VALUE (www.value-cost.eu) has been brought into life. VALUE is a research network with participants from currently 23 European countries running from 2012 to 2015. Its main aim is to systematically validate and develop downscaling methods for climate change research in order to improve regional climate change scenarios for use in climate impact studies. Inspired by the co-design idea of the international research initiative "future earth", stakeholders of climate change information have been involved in the definition of research questions to be addressed and are actively participating in the network. The key idea of VALUE is to identify the relevant weather and climate characteristics required as input for a wide range of impact models and to define an open framework to systematically validate these characteristics. Based on a range of benchmark data sets, in principle every downscaling method can be validated and compared with competing methods. The results of this exercise will directly provide end users with important information about the uncertainty of regional climate scenarios, and will furthermore provide the basis for further developing downscaling methods. This presentation will provide background information on VALUE and discuss the identified characteristics and the validation framework.

Understanding Water Storage Practices of Urban Residents of an Endemic Dengue Area in Colombia: Perceptions, Rationale and Socio-Demographic Characteristics

PubMed Central

González-Uribe, Catalina; Cortés, Sebastian; Quintero, Juliana

2015-01-01

Introduction The main preventive measure against dengue virus transmission is often based on actions to control Ae. Aegypti reproduction by targeting water containers of clean and stagnant water. Household water storage has received special attention in prevention strategies but the evidence about the rationale of this human practice is limited. The objective was to identify and describe water storage practices among residents of an urban area in Colombia (Girardot) and its association with reported perceptions, rationales and socio-demographic characteristics with a mixed methods approach. Methods Knowledge, attitudes and practices and entomological surveys from 1,721 households and 26 semi-structured interviews were conducted among residents of Girardot and technicians of the local vector borne disease program. A multivariate analysis was performed to identify associations between a water storage practice and socio-demographic characteristics, and knowledge, attitudes and practices about dengue and immature forms of the vector, which were then triangulated with qualitative information. Results Water storage is a cultural practice in Girardot. There are two main reasons for storage: The scarcity concern based on a long history of shortages of water in the region and the perception of high prices in water rates, contrary to what was reported by the local water company. The practice of water storage was associated with being a housewife (Inverse OR: 2.6, 95% CI 1.5 -4.3). The use of stored water depends on the type of container used, while water stored in alberca (Intra household cement basins) is mainly used for domestic cleaning chores, water in plastic containers is used for cooking. Conclusions It is essential to understand social practices that can increase or reduce the number of breeding sites of Ae. Aegypti. Identification of individuals who store water and the rationale of such storage allow a better understanding of the social dynamics that lead to water accumulation. PMID:26061628

Performance of new alternative providers of primary care services in England: an observational study

PubMed Central

Greaves, Felix; Laverty, Anthony A; Pape, Utz; Ratneswaren, Anenta; Majeed, Azeem

2015-01-01

Summary Objectives Health system reforms in England are opening broad areas of clinical practice to new providers of care. As part of these reforms, new entrants – including private companies – have been allowed into the primary care market under ‘alternative provider of medical services’ contracting mechanisms since 2004. The characteristics and performance of general practices working under new alternative provider contracts are not well described. We sought to compare the quality of care provided by new entrant providers to that provided by the traditional model of general practice. Design Open cohort study of English general practices. We used linear regression in cross-sectional and time series analyses, adjusting for practice and population characteristics, to compare quality in practices using alternative provider contracts to traditional practices. We created regression models using practice fixed effects to estimate the impact of practices changing to the new contract type. Setting The English National Health Service. Participants All general practices open from 2008/2009 to 2012/2013. Main outcome measures Seventeen established quality indicators – covering clinical effectiveness, efficiency, access and patient experience. Results In total, 4.1% (347 of 8300) of general practices in England were run by alternative contract providers. These practices tended to be smaller, and serve younger, more diverse and more deprived populations than traditional providers. Practices run by alternative providers performed worse than traditional providers on 15 of 17 indicators after adjusting for practice and population characteristics (p < 0.01 for all). Switching to a new alternative provider contract did not result in improved performance. Conclusions The introduction of new alternative providers to deliver primary care services in England has not led to improvements in quality and may have resulted in worse care. Regulators should ensure that new entrants to clinical provider markets are performing to adequate standards and at least as well as traditional providers. PMID:25908312

What keeps family physicians busy in Portugal? A multicentre observational study of work other than direct patient contacts

PubMed Central

Granja, Mónica; Ponte, Carla; Cavadas, Luís Filipe

2014-01-01

Objectives To quantify the time spent by family physicians (FP) on tasks other than direct patient contact, to evaluate job satisfaction, to analyse the association between time spent on tasks and physician characteristics, the association between the number of tasks performed and physician characteristics and the association between time spent on tasks and job satisfaction. Design Cross-sectional, using time-and-motion techniques. Two workdays were documented by direct observation. A significance level of 0.05 was adopted. Setting Multicentric in 104 Portuguese family practices. Participants A convenience sample of FP, with lists of over 1000 patients, teaching senior medical students and first-year family medicine residents in 2012, was obtained. Of the 217 FP invited to participate, 155 completed the study. Main outcomes measured Time spent on tasks other than direct patient contact and on the performance of more than one task simultaneously, the number of direct patient contacts in the office, the number of indirect patient contacts, job satisfaction, demographic and professional characteristics associated with time spent on tasks and the number of different tasks performed, and the association between time spent on tasks and job satisfaction. Results FP (n=155) spent a mean of 143.6 min/day (95% CI 135.2 to 152.0) performing tasks such as prescription refills, teaching, meetings, management and communication with other professionals (33.4% of their workload). FP with larger patient lists spent less time on these tasks (p=0.002). Older FP (p=0.021) and those with larger lists (p=0.011) performed fewer tasks. The mean job satisfaction score was 3.5 (out of 5). No association was found between job satisfaction and time spent on tasks. Conclusions FP spent one-third of their workday in coordinating care, teaching and managing. Time devoted to these tasks decreases with increasing list size and physician age. PMID:24934208

Septic abortion: a review of social and demographic characteristics.

PubMed

Osazuwa, Henry; Aziken, Michael

2007-02-01

Septic abortion is a significant health problem with short- and long-term complications that affect the quality of life of those fortunate enough to avoid mortality. Both spontaneous and induced abortion can result in septic complications, with the latter disproportionately higher. Its incidence is high in environments with restrictive abortion laws, as clandestine procedures by non-doctors in unhygienic settings are prevalent. This study shows that it is still more common among teenagers and mainly performed by health professionals, which means that health care interventions should be re-evaluated and appropriately directed to preserve the reproductive health status of this vulnerable population.

Development of dual sensor hand-held detector

NASA Astrophysics Data System (ADS)

Sezgin, Mehmet

2010-04-01

In this paper hand-held dual sensor detector development requirements are considered dedicated to buried object detection. Design characteristics of such a system are categorized and listed. Hardware and software structures, ergonomics, user interface, environmental and EMC/EMI tests to be applied and performance test issues are studied. Main properties of the developed system (SEZER) are presented, which contains Metal Detector (MD) and Ground Penetrating Radar (GPR). The realized system has ergonomic structure and can detect both metallic and non-metallic buried objects. Moreover classification of target is possible if it was defined to the signal processing software in learning phase.

The CP-PACS parallel computer

NASA Astrophysics Data System (ADS)

Ukawa, Akira

1998-05-01

The CP-PACS computer is a massively parallel computer consisting of 2048 processing units and having a peak speed of 614 GFLOPS and 128 GByte of main memory. It was developed over the four years from 1992 to 1996 at the Center for Computational Physics, University of Tsukuba, for large-scale numerical simulations in computational physics, especially those of lattice QCD. The CP-PACS computer has been in full operation for physics computations since October 1996. In this article we describe the chronology of the development, the hardware and software characteristics of the computer, and its performance for lattice QCD simulations.

Development of automated control system for wood drying

NASA Astrophysics Data System (ADS)

Sereda, T. G.; Kostarev, S. N.

2018-05-01

The article considers the parameters of convective wood drying which allows changing the characteristics of the air that performs drying at different stages: humidity, temperature, speed and direction of air movement. Despite the prevalence of this type of drying equipment, the main drawbacks of it are: the high temperature and humidity, negatively affecting the working conditions of maintenance personnel when they enter the drying chambers. It makes the automation of wood drying process necessary. The synthesis of a finite state of a machine control of wood drying process is implemented on a programmable logic device Omron.

Research on Aerodynamic Characteristics of Composite powered Unmanned Airship

NASA Astrophysics Data System (ADS)

Chen, Yu; Wang, Yun; Wang, Lu; Ma, Chengyu; Xia, Jun

2017-10-01

The main structure of the composite powered unmanned airship is consists of airbags and four-rotor system, which airbag increases the available lift, and has more advantages in terms of load and flight when compared with the traditional four-rotor. In order to compare the aerodynamic performance of the composite powered unmanned airship and the traditional four-rotor, the SIMPLE algorithm and the RNG k-epsilon model method are be used. The energy consumption of the composite powered unmanned airship is lesser than the traditional four-rotor under the same load and range was found.

Acquisition and production of skilled behavior in dynamic decision-making tasks

NASA Technical Reports Server (NTRS)

Kirlik, Alex

1992-01-01

Currently, two main approaches exist for improving the human-machine interface component of a system in order to improve overall system performance - display enhancement and intelligent decision making. Discussed here are the characteristic issues of these two decision-making strategies. Differences in expert and novice decision making are described in order to help determine whether a particular strategy may be better for a particular type of user. Research is outlined to compare and contrast the two technologies, as well as to examine the interaction effects introduced by the different skill levels and the different methods for training operators.

Memcomputing with membrane memcapacitive systems

NASA Astrophysics Data System (ADS)

Pershin, Y. V.; Traversa, F. L.; Di Ventra, M.

2015-06-01

We show theoretically that networks of membrane memcapacitive systems—capacitors with memory made out of membrane materials—can be used to perform a complete set of logic gates in a massively parallel way by simply changing the external input amplitudes, but not the topology of the network. This polymorphism is an important characteristic of memcomputing (computing with memories) that closely reproduces one of the main features of the brain. A practical realization of these membrane memcapacitive systems, using, e.g., graphene or other 2D materials, would be a step forward towards a solid-state realization of memcomputing with passive devices.

The Use of Multiple Correspondence Analysis to Explore Associations between Categories of Qualitative Variables in Healthy Ageing.

PubMed

Costa, Patrício Soares; Santos, Nadine Correia; Cunha, Pedro; Cotter, Jorge; Sousa, Nuno

2013-01-01

The main focus of this study was to illustrate the applicability of multiple correspondence analysis (MCA) in detecting and representing underlying structures in large datasets used to investigate cognitive ageing. Principal component analysis (PCA) was used to obtain main cognitive dimensions, and MCA was used to detect and explore relationships between cognitive, clinical, physical, and lifestyle variables. Two PCA dimensions were identified (general cognition/executive function and memory), and two MCA dimensions were retained. Poorer cognitive performance was associated with older age, less school years, unhealthier lifestyle indicators, and presence of pathology. The first MCA dimension indicated the clustering of general/executive function and lifestyle indicators and education, while the second association was between memory and clinical parameters and age. The clustering analysis with object scores method was used to identify groups sharing similar characteristics. The weaker cognitive clusters in terms of memory and executive function comprised individuals with characteristics contributing to a higher MCA dimensional mean score (age, less education, and presence of indicators of unhealthier lifestyle habits and/or clinical pathologies). MCA provided a powerful tool to explore complex ageing data, covering multiple and diverse variables, showing if a relationship exists and how variables are related, and offering statistical results that can be seen both analytically and visually.

Micro-fabrication method of graphite mesa microdevices based on optical lithography technology

NASA Astrophysics Data System (ADS)

Zhang, Cheng; Wen, Donghui; Zhu, Huamin; Zhang, Xiaorui; Yang, Xing; Shi, Yunsheng; Zheng, Tianxiang

2017-12-01

Graphite mesa microdevices have incommensurate contact nanometer interfaces, superlubricity, high-speed self-retraction, and other characteristics, which have potential applications in high-performance oscillators and micro-scale switches, memory devices, and gyroscopes. However, the current method of fabricating graphite mesa microdevices is mainly based on high-cost, low efficiency electron beam lithography technology. In this paper, the processing technologies of graphite mesa microdevices with various shapes and sizes were investigated by a low-cost micro-fabrication method, which was mainly based on optical lithography technology. The characterization results showed that the optical lithography technology could realize a large-area of patterning on the graphite surface, and the graphite mesa microdevices, which have a regular shape, neat arrangement, and high verticality could be fabricated in large batches through optical lithography technology. The experiments and analyses showed that the graphite mesa microdevices fabricated through optical lithography technology basically have the same self-retracting characteristics as those fabricated through electron beam lithography technology, and the maximum size of the graphite mesa microdevices with self-retracting phenomenon can reach 10 µm  ×  10 µm. Therefore, the proposed method of this paper can realize the high-efficiency and low-cost processing of graphite mesa microdevices, which is significant for batch fabrication and application of graphite mesa microdevices.

A case study of dissolved air flotation for seasonal high turbidity water in Korea.

PubMed

Kwon, S B; Ahn, H W; Ahn, C J; Wang, C K

2004-01-01

A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.

[Use of midazolam in hospitalized patients: analysis of medical practice].

PubMed

Giroud, Mathilde; Sellier, Elodie; Laval, Guillemette

2013-09-01

To evaluate the prevalence and the characteristics of use of midazolam among hospitalized patients and to analyze physicians' representation of this medicine. We conducted a retrospective study between 1st May and 22nd May 2011 in Grenoble University Hospital in France. All patients receiving midazolam during the study period were included, excepted if the prescription was performed in intensive care units, operating rooms or in pediatric units. Physicians from the different units were asked about the characteristics of patients receiving midazolam and about their practice concerning the use of midazolam. Forty-four patients were included, 82 % of whom having a cancer. The prevalence of prescription of midazolam was 3.3 % (44/1,323), 2.8 % (37/1,323) for anxiety relieving and 0.8 % (11/1,323) for sedation. The main refractory symptoms that justified the prescription were dyspnea (36.4 %), confusion (29.5 %), pain (27.3 %) and psychological suffering (27.3 %). Twenty-eight physicians were asked about their practice. The main representations of midazolam were the stop of active treatment (46.5 %) and premature cause of death (46.5 %). Practice of sedation is under-estimated by physicians as they have difficulties to differentiate anxiety relieving and sedation and they have difficulties to initiate a sedation. A guideline to help physicians using midazolam could improve practice.

Genetic diversity among 16 genotypes of Coffea arabica in the Brazilian cerrado.

PubMed

Machado, C M S; Pimentel, N S; Golynsk, A; Ferreira, A; Vieira, H D; Partelli, F L

2017-09-21

For the selection of coffee plants that have favorable characteristics, it is necessary to evaluate variables related to production. Knowledge of the genetic divergence of arabica coffee is of extreme importance, as this knowledge can be associated with plant breeding programs in order to combine genetic divergence with good productive performance. The objective of this study was to evaluate the genetic divergence among 16 genotypes of Coffea arabica with the purpose of identifying the most dissimilar genotypes for the establishment of breeding programs and adaptation to the Brazilian cerrado. The genetic divergence was evaluated using multivariate procedures, the analysis of the average grouping unweighted pair group method with arithmetic mean (UPGMA) and main components in 2013 and 2014. Eight characters were evaluated in an experiment conducted in Morrinhos, Goiás. The presence of genetic divergence among the 16 C. arabica genotypes under cerrado conditions was recorded. The formation of UPGMA groups for the evaluated characteristics was pertinent due to the number of genotypes. The first three major components accounted for 81.77% of the total variance. The genotype H-419-3-4-4-13(C-241) of low size was the most divergent, followed by Catucaí 2 SL and Catiguá MG2, according to the main components.

Toward High-Performance Lithium-Sulfur Batteries: Upcycling of LDPE Plastic into Sulfonated Carbon Scaffold via Microwave-Promoted Sulfonation.

PubMed

Kim, Patrick J; Fontecha, Harif D; Kim, Kyungho; Pol, Vilas G

2018-05-02

Lithium-sulfur batteries were intensively explored during the last few decades as next-generation batteries owing to their high energy density (2600 Wh kg -1 ) and effective cost benefit. However, systemic challenges, mainly associated with polysulfide shuttling effect and low Coulombic efficiency, plague the practical utilization of sulfur cathode electrodes in the battery market. To address the aforementioned issues, many approaches have been investigated by tailoring the surface characteristics and porosities of carbon scaffold. In this study, we first present an effective strategy of preparing porous sulfonated carbon (PSC) from low-density polyethylene (LDPE) plastic via microwave-promoted sulfonation. Microwave process not only boosts the sulfonation reaction of LDPE but also induces huge amounts of pores within the sulfonated LDPE plastic. When a PSC layer was utilized as an interlayer in lithium-sulfur batteries, the sulfur cathode delivered an improved capacity of 776 mAh g -1 at 0.5C and an excellent cycle retention of 79% over 200 cycles. These are mainly attributed to two materialistic benefits of PSC: (a) porous structure with high surface area and (b) negatively charged conductive scaffold. These two characteristics not only facilitate the improved electrochemical kinetics but also effectively block the diffusion of polysulfides via Coulomb interaction.

Effect of heating rate on thermal cracking characteristics and kinetics of Xinjiang oil sand bitumen by TG-FTIR

NASA Astrophysics Data System (ADS)

Hao, Junhui; Zhang, Jinhong; Qiao, Yingyun; Tian, Yuanyu

2017-08-01

This work was aimed to investigate effects of heating rate on thermal cracking behaviors, distribution of gaseous products and activation energy of the thermal cracking process of Xinjiang oil sand bitumen (OSB). The thermal cracking experiments of Xinjiang OSB were performed by using thermogravimetric analyzer (TGA) at various heating rates of 10, 20, 50, 80 and 120 K/min. The evolving characteristic of gaseous products produced from the thermal cracking process was evaluated by the Fourier transform infrared spectrometry (FTIR) connected with TG. The kinetic parameters of the thermal cracking process of Xinjiang OSB at each of heating rate were determined by the Coats-Redfern model. The result show that the temperature intervals of DE volatilization stage and main reaction stage, the ((dw/dt) max and Tmax in thermal cracking process of Xinjiang OSB all increased with the increasing heating rate. While the heating rate has not obvious effect on the coke yield of Xinjiang OSB. Furthermore, the maximum absorbance of gaseous products and corresponding temperature became larger as the heating rate increases. The activation energy of this two stage both presented increasing trend with the rising heating rate, while the increasing content of that of DE volatilization stage was weaker compared to that of main reaction stage.

[Anesthesia-related cardiac arrest in children. Data from a tertiary referral hospital registry].

PubMed

Sanabria-Carretero, P; Ochoa-Osorio, C; Martín-Vega, A; Lahoz-Ramón, A; Rodríguez-Pérez, E; Reinoso-Barbero, F; Goldman-Tarlovsky, L

2013-10-01

The aim of this study is to analyze the cardiac arrests related to anesthesia in a tertiary children's hospital, in order to identify risk factors that would lead to opportunities for improvement. A 5-year retrospective study was conducted on anesthesia related cardiac arrest occurring in pediatric patients. All urgent and elective anesthetic procedures performed by anesthesiologists were included. Data collected included patient characteristics, the procedure, the probable cause, and outcome of the cardiac arrest. Odds ratio was calculated by univariate analysis to determine the clinical factors associated with cardiac arrest and mortality. There were a total of 15 cardiac arrests related to anesthesia in 43,391 anesthetic procedures (3.4 per 10,000), with an incidence in children with ASA I-II versus ASA≥III of 0.28 and 19.27 per 10,000, respectively. The main risk factors were children ASA≥III (P<.001), less than one month old (P<.001), less than one year old (P<.001), emergency procedures (P<.01), cardiac procedures (P<.001) and procedures performed in the catheterization laboratory (P<.05). The main causes of cardiac arrest were cardiovascular (53.3%), mainly due to hypovolemia, and cardiovascular depression associated with induction of anesthesia, followed by respiratory causes (20%), and medication causes (20%). The incidence of mortality and neurological injury within the first 24h after the cardiac arrest was 0.92 and 1.38 per 10,000, respectively. The mortality in the first 3 months was 1.6 per 10,000. The main causes of death were ASA≥III, age under one year, pulmonary arterial hypertension, cardiac arrest in areas remote from the surgery area, a duration of cardiopulmonary resuscitation over 20min, and when hypothermia was not applied after cardiac arrest. The main risk factors for cardiac arrest were ASA≥III, age under one year, emergency procedures, cardiology procedures and procedures performed in the catheterization laboratory. The main cause of the cardiac arrest was due mainly to cardiovascular hypovolemia. All patients who died or had neurological injury were ASA≥III. Pulmonary arterial hypertension is a risk of anesthesia-related mortality. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Osteomyelitis: a descriptive study.

PubMed

Prieto-Pérez, Laura; Pérez-Tanoira, Ramón; Petkova-Saiz, Elizabet; Pérez-Jorge, Concepción; Lopez-Rodriguez, Cristina; Alvarez-Alvarez, Beatriz; Polo-Sabau, Jorge; Esteban, Jaime

2014-03-01

To analyze the incidence and clinical-microbiological characteristics of osteomyelitis (OM) in a tertiary Spanish hospital. All cases diagnosed with OM between January 2007 and December 2010 were retrospectively reviewed. The variables examined include epidemiological characteristics, risk factors, affected bone, radiographic changes, histology, microbiological culture results, antibiotic treatment, and the need for surgery. Sixty-three cases of OM were diagnosed. Twenty-six patients (41.3%) had acute OM whereas 37 patients (58.7%) were classified as chronic OM. OM may result from haematogenous or contiguous microbial seeding. In this group, 49 patients (77.8%) presented with OM secondary to a contiguous source of infection and 14 patients had hematogenous OM (22.2%). Staphylococcus aureus was the most commonly found microorganism. OM mainly affected patients with risk factors related to the presence of vascular diseases. Antibiotic treatment must be guided by susceptibility patterns of individual microorganisms, although it must be performed together with surgery in most of the cases.

A novel c.240_241insGG mutation in NDP gene in a family with Norrie disease.

PubMed

Andarva, Monavvar; Jamshidi, Javad; Ghaedi, Hamid; Daftarian, Narsis; Emamalizadeh, Babak; Alehabib, Elham; Taghavi, Shaghyegh; Pouriran, Ramin; Darvish, Hossein

2018-03-01

Norrie disease (ND) is a rare, X-linked recessive disorder with the main characteristic of early childhood blindness. The aim of the present study was to identify the genetic cause of the disease and the phenotypic characteristics of the patients in an Iranian family with four affected males with ND. Norrie disease pseudoglioma (NDP) gene was sequenced and clinical examination was performed on patients. A GG dinucleotide insertion in exon 3 (c.240_241insGG) of NDP was detected in all patients. The mutation caused a frameshift and an early stop codon (p.Phe81Glyfs*23). A novel mutation was found in the NDP gene in the affected males of the family. As the mutation was absent in the normal male members of the family, it should be the genetic cause of the disease. © 2017 Optometry Australia.

A high-fidelity weather time series generator using the Markov Chain process on a piecewise level

NASA Astrophysics Data System (ADS)

Hersvik, K.; Endrerud, O.-E. V.

2017-12-01

A method is developed for generating a set of unique weather time-series based on an existing weather series. The method allows statistically valid weather variations to take place within repeated simulations of offshore operations. The numerous generated time series need to share the same statistical qualities as the original time series. Statistical qualities here refer mainly to the distribution of weather windows available for work, including durations and frequencies of such weather windows, and seasonal characteristics. The method is based on the Markov chain process. The core new development lies in how the Markov Process is used, specifically by joining small pieces of random length time series together rather than joining individual weather states, each from a single time step, which is a common solution found in the literature. This new Markov model shows favorable characteristics with respect to the requirements set forth and all aspects of the validation performed.

[Analysis on preparation and characterization of asiaticoside-loaded flexible nanoliposomes].

PubMed

Ren, Yan; He, Xing-Dong; Shang, Bei-Cheng; Bao, Xiu-Kun; Wang, Yan-Fang; Ma, Ji-Sheng

2013-10-01

Asiaticoside is a compound extracted from traditional Chinese medicine Centella asiatica, and mainly used in wound healing and scar repair in clinical, with notable efficacy. However, its poor transdermal absorption and short action time restrict its wide application. In this experiment, the reserve-phase-extrusion-lyophilization method was conducted to prepare the lyophilized asiaticoside-loaded flexible nanoliposomes (LAFL). Its characteristics including electron microscope structure, particle size, Zeta potential, entrapment rate, drug-loading rate, stability and drug release were determined with the intelligent transdermal absorption instrument. LAFL were white spheroids, with pH, particle size and zeta potential of 7. 03, 70. 14 nm and - 36. 5 mV, respectively. The average entrapment rate of the 3 batch samples were 31. 43% , and the average asiaticoside content in 1 mg lyophilized simple was 0. 134 mg. The results indicated that LAFL have good physicochemical properties and pharmaceutical characteristics, with an improved transdermal performance.

RCA: A route city attraction model for air passengers

NASA Astrophysics Data System (ADS)

Huang, Feihu; Xiong, Xi; Peng, Jian; Guo, Bing; Tong, Bo

2018-02-01

Human movement pattern is a research hotspot of social computing and has practical values in various fields, such as traffic planning. Previous studies mainly focus on the travel activities of human beings on the ground rather than those in the air. In this paper, we use the reservation records of air passengers to explore air passengers' movement characteristics. After analyzing the effect of the route-trip length on the throughput, we find that most passengers eventually return to their original departure city and that the mobility of air passengers is not related to the route length. Based on these characteristics, we present a route city attraction (RCA) model, in which GDP or population is considered for the calculation of the attraction. The sub models of our RCA model show the better prediction performance of throughput than the radiation model and the gravity model.

Characteristics and engineering properties of residual soil of volcanic deposits

NASA Astrophysics Data System (ADS)

Wibawa, Y. S.; Sugiarti, K.; Soebowo, E.

2018-02-01

Residual soil knowledge of volcanic-sedimentary rock products provides important information on the soil bearing capacity and its engineering properties. The residual soil is the result of weathering commonly found in unsaturated conditions, having varied geotechnical characteristics at each level of weathering. This paper summarizes the results of the research from the basic engineering properties of residual soil of volcanic-sedimentary rocks from several different locations. The main engineering properties of residual soil such as specific gravity, porosity, grain size, clay content (X-Ray test) and soil shear strength are performed on volcanic rock deposits. The results show that the variation of the index and engineering properties and the microstructure properties of residual soil have the correlation between the depths of weathering levels. Pore volume and pore size distribution on weathered rock profiles can be used as an indication of weathering levels in the tropics.

Long-term exposure to zero-g and the gastro-intestinal tract function

NASA Technical Reports Server (NTRS)

Mccormack, Percial D.

1989-01-01

The gastrointestinal tract (GIT) function is described with emphasis placed on its important role to smooth, delay, and modify sudden fluid load stress applied to the fluid distribution control system in the body. Two basic components of the GIT are considered: stomach dynamics, which involves storage, mixing, and discharge of food into the intestine after addition of gastric juices; and absorption of water and electrolytes from the small intestine. A dynamic model of these components is described, along with performance characteristics computed consecutively for one g and zero g conditions. The main impact of the zero g condition appears to be through a change in osmotic driven transport across the gut wall. A dramatic change in transport characteristics is predicted with implication for many body systems (the immune system in particular) during long-term exposure to zero g. Experimental measurements in zero g are needed to evaluate these predictions.

Space charge characteristics of fluorinated polyethylene: Different effects of fluorine and oxygen

NASA Astrophysics Data System (ADS)

Zhao, Ni; Nie, Yongjie; Li, Shengtao

2018-04-01

Direct fluorination are proved having obvious effect on space charge characteristics of polyethylene. It is believed that fluorine has a positive effect on suppressing space charge injection while oxygen impurity has a negative effect. However, the mechanism for the opposite effect of fluorine and oxygen is still not clear. In this paper, the different effects of fluorine and oxygen on space charge characteristics of fluorinated low density polyethylene (LDPE) are investigated on the basis of dielectric property, chemical constitutes and trap performance of surface fluorinated layers. The results show that direct fluorination has obvious effect on chemical constitutes and dielectric properties of surface fluorinated layer. Introduced fluorine is the main factor for suppressing charge injection from the electrodes, because it seriously changes the chemical constitutes and further the trap properties of the surface fluorinated layer. While introduction of oxygen results in heterocharges and makes space charge distribution complex, due to the ionization of generated small groups like C=O containing groups. Moreover, direct fluorination will result in cleavage of some LDPE molecules whatever there is oxygen impurity or not.

Prediction of dynamic and aerodynamic characteristics of the centrifugal fan with forward curved blades

NASA Astrophysics Data System (ADS)

Polanský, Jiří; Kalmár, László; Gášpár, Roman

2013-12-01

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic "A" variant contains 12 blades. The geometry of second "B" variant contains 12 blades and 12 semi-blades with optimal length [1]. The third, control variant "C" contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys. Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. Pressure pulsations are evaluated by using frequency analysis for each variant and working condition.

Study on characteristics of PVDF/nano-clay composite polymer electrolyte using PVP as pore-forming agent

NASA Astrophysics Data System (ADS)

Dyartanti, Endah R.; Purwanto, Agus; Widiasa, I. Nyoman; Susanto, Heru

2016-02-01

Polyvinylidene fluoride (PVDF) based polymer electrolytes have a high dielectric constant, which can assist in greater ionization of lithium salts. The main advantages of PVDF are its durability in long battery operation and its ability to be a good ion conductor. However, the limitation of this polymer is its crystalline molecular structure. Dispersing nano-particles in the polymer matrix may improve the characteristics of the PVDF polymer. This paper aims to investigate the impact of nano-clay addition on the characteristics of PVDF polymer to be used as a polymer electrolyte membrane. In addition, the effect of poly(vinyl pyrrolidone) (PVP) is also investigated. The membrane was prepared by phase separation method whereas the polymer electrolyte membranes was prepared by immersing into 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate/dimethyl carbonate (EC/DMC) electrolytes for 1 h. The membranes were characterized by scanning electron microscope (SEM), porosity and electrolyte uptake and performance in battery cell. The results showed that both nano-clay and PVP have significant impacts on the improvement of PVDF membranes to be used as polymer electrolyte.

Evaluation of agricultural residues pyrolysis under non-isothermal conditions: Thermal behaviors, kinetics, and thermodynamics.

PubMed

Chen, Jianbiao; Wang, Yanhong; Lang, Xuemei; Ren, Xiu'e; Fan, Shuanshi

2017-10-01

The thermal conversion characteristics, kinetics, and thermodynamics of agricultural residues, rape straw (RS) and wheat bran (WB), were investigated under non-isothermal conditions. TGA experiments showed that the pyrolysis characteristics of RS were quite different from those of WB. As reflected by the comprehensive devolatilization index, when the heating rate increased from 10 to 30Kmin -1 , the pyrolysis performance of RS and WB were improved 5.27 and 5.96 times, respectively. The kinetic triplets of the main pyrolysis process of agricultural residues were calculated by the Starink method and the integral master-plots method. Kinetic analysis results indicated that the most potential kinetic models for the pyrolysis of RS and WB were D 2 and F 2.7 , respectively. The thermodynamic parameters (ΔH, ΔG, and ΔS) were determined by the activated complex theory. The positive ΔH, positive ΔG, and negative ΔS at characteristic temperatures validated that the pyrolysis of agricultural residues was endothermic and non-spontaneous. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Use of Sensory Analysis Techniques to Assess the Quality of Indoor Air.

PubMed

Lewkowska, Paulina; Dymerski, Tomasz; Gębicki, Jacek; Namieśnik, Jacek

2017-01-02

The quality of indoor air is one of the significant elements that influences people's well-being and health inside buildings. Emissions of pollutants, which may cause odor nuisance, are the main reason for people's complaints regarding the quality of indoor air. As a result, it is necessary to perform tests aimed at identifying the sources of odors inside buildings. The article contains basic information on the characteristics of the sources of indoor air pollution and the influence of the odor detection threshold on people's health and comfort. An attempt was also made to classify and use sensory analysis techniques to perform tests of the quality of indoor air, which would enable identification of sensory experience and would allow for indication of the degree of their intensity.

Slot Optimization Design of Induction Motor for Electric Vehicle

NASA Astrophysics Data System (ADS)

Shen, Yiming; Zhu, Changqing; Wang, Xiuhe

2018-01-01

Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

[Spiral CT angiography in practice].

PubMed

Pavcec, Zlatko; Zokalj, Ivan; Rumboldt, Zoran; Pal, Andrej; Saghir, Hussein; Ozretić, David; Latin, Branko; Perhoć, Zeljka; Marotti, Miljenko

2005-01-01

Incidence of vascular diseases and development of new radiologic techniques in the last three decades has given strong impuls for introduction of non-invasive vascular diagnostic methods. Thanks to the introduction of Doppler ultrasound, new types of computed tomography (CT) and magnetic resonance (MR) scanners, non-invasive vascular diagnostic methods are replacing conventional invasive (catheter) angiographic methods. Computed tomographic angiography (CTA) is a noninvasive vascular diagnostic method based on continuous scanning with CT scanner during intravenous application of contrast material. Performing of CTA is possible after introduction of spiral CT technique whose characteristics are short imaging time and volumetric data acquisition. The main goal of this article, based on our experiences, is to review the role of CTA, performed on single-slice CT scanner, in managment of patients with vascular pathology.

Instance Search Retrospective with Focus on TRECVID

PubMed Central

Awad, George; Kraaij, Wessel; Over, Paul; Satoh, Shin’ichi

2017-01-01

This paper presents an overview of the Video Instance Search benchmark which was run over a period of 6 years (2010–2015) as part of the TREC Video Retrieval (TRECVID) workshop series. The main contributions of the paper include i) an examination of the evolving design of the evaluation framework and its components (system tasks, data, measures); ii) an analysis of the influence of topic characteristics (such as rigid/non rigid, planar/non-planar, stationary/mobile on performance; iii) a high-level overview of results and best-performing approaches. The Instance Search (INS) benchmark worked with a variety of large collections of data including Sound & Vision, Flickr, BBC (British Broadcasting Corporation) Rushes for the first 3 pilot years and with the small world of the BBC Eastenders series for the last 3 years. PMID:28758054

Performance of a CW double electric discharge for supersonic CO lasers

NASA Technical Reports Server (NTRS)

Stanton, A. C.; Hanson, R. K.; Mitchner, M.

1980-01-01

The results of an experimental investigation of a CW double discharge in supersonic CO mixtures are reported. Stable discharges in CO/N2 and CO/Ar mixtures, with a maximum energy loading of 0.5 eV/CO molecule, were achieved in a small-scale continuous-flow supersonic channel. Detailed measurements of the discharge characteristics were performed, including electrostatic probe measurements of floating potential and electron number density and spectroscopic measurements of the CO vibrational population distributions. The results of these measurements indicate that the vibrational excitation efficiency of the discharge is approximately 60%, for moderate levels of main discharge current. These experiments, on a small scale, demonstrate that the double-discharge scheme provides adequate vibrational energy loading for efficient CO laser operation under CW supersonic flow conditions.

A Study on Characteristics and Competencies Needed by Teachers of the Mentally Retarded.

ERIC Educational Resources Information Center

Ho, Hua-Kuo

This study assessed the characteristics of 134 teachers of the mentally retarded in Taiwan, and surveyed 321 teachers of the retarded concerning desirable teacher characteristics and competencies. Four main conclusions were drawn: (1) outstanding teachers of the retarded were highly rated for such characteristics as "flexibility of…

Energy characteristics of Darrieus rotor ( review)

NASA Astrophysics Data System (ADS)

Gorelov, D. N.

2010-09-01

Presented below is the review of the results of experimental studies of energy characteristics of Darrieus rotor with vertical rotation axis. Influence of main geometry parameters of the rotor on its energy characteristics has been analyzed. It is shown that Darrieus rotor may have the higher level of energy characteristics than the best propeller wind turbines.

Performance of the upgraded LTP-II at the ALS Optical Metrology Laboratory

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

Advanced Light Source; Yashchuk, Valeriy V; Kirschman, Jonathan L.

2008-07-14

The next generation of synchrotrons and free electron laser facilities requires x-ray optical systems with extremely high performance, generally of diffraction limited quality. Fabrication and use of such optics requires adequate, highly accurate metrology and dedicated instrumentation. Previously, we suggested ways to improve the performance of the Long Trace Profiler (LTP), a slope measuring instrument widely used to characterize x-ray optics at long spatial wavelengths. The main way is use of a CCD detector and corresponding technique for calibration of photo-response non-uniformity [J. L. Kirschman, et al., Proceedings of SPIE 6704, 67040J (2007)]. The present work focuses on the performancemore » and characteristics of the upgraded LTP-II at the ALS Optical Metrology Laboratory. This includes a review of the overall aspects of the design, control system, the movement and measurement regimes for the stage, and analysis of the performance by a slope measurement of a highly curved super-quality substrate with less than 0.3 microradian (rms)slope variation.« less

Co-combustion characteristics and blending optimization of tobacco stem and high-sulfur bituminous coal based on thermogravimetric and mass spectrometry analyses.

PubMed

Zhang, Kaihua; Zhang, Kai; Cao, Yan; Pan, Wei-ping

2013-03-01

Despite much research on co-combustion of tobacco stem and high-sulfur coal, their blending optimization has not been effectively found. This study investigated the combustion profiles of tobacco stem, high-sulfur bituminous coal and their blends by thermogravimetric analysis. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions were also studied by thermogravimetric and mass spectrometry analyses. The results indicated that combustion of tobacco stem was more complicated than that of high-sulfur bituminous coal, mainly shown as fixed carbon in it was divided into two portions with one early burning and the other delay burning. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions of the blends present variable trends with the increase of tobacco stem content. Taking into account the above three factors, a blending ratio of 0–20% tobacco stem content is conservatively proposed as optimum amount for blending. Copyright © 2012 Elsevier Ltd. All rights reserved.

[The instruments for subjective assessment of work-related stress].

PubMed

Conway, P M

2009-01-01

The instruments for subjective assessment of work-related stress are aimed to evaluate individual perceptions of aspects that are crucial in the causal process linking psychosocial exposure to harmful physical and psychological health effects. Subjective assessment is most commonly performed by means of self-administered questionnaires, non least for their ability to hold down financial and economic costs of both field studies and data analyses. A common problem is that, for the major part of these questionnaires, no Italian validated (or accept) versions exist. Among available questionnaires, those that have been applied to a higher number of subjects in Italy are the Job Content Questionnaire, the Effort/Reward Imbalance Questionnaire, the Occupational Stress Indicator and the Multidimensional Questionnaire of Organizational Health. In this contribution, the main characteristics of the above-mentioned instruments are depicted. Finally, important aspects relating to the usage of self-administered questionnaires are emphasized, mainly when field evaluations are undertaken in specific work contexts.

Analysis of Co-Tunneling Current in Fullerene Single-Electron Transistor

NASA Astrophysics Data System (ADS)

KhademHosseini, Vahideh; Dideban, Daryoosh; Ahmadi, MohammadTaghi; Ismail, Razali

2018-05-01

Single-electron transistors (SETs) are nano devices which can be used in low-power electronic systems. They operate based on coulomb blockade effect. This phenomenon controls single-electron tunneling and it switches the current in SET. On the other hand, co-tunneling process increases leakage current, so it reduces main current and reliability of SET. Due to co-tunneling phenomenon, main characteristics of fullerene SET with multiple islands are modelled in this research. Its performance is compared with silicon SET and consequently, research result reports that fullerene SET has lower leakage current and higher reliability than silicon counterpart. Based on the presented model, lower co-tunneling current is achieved by selection of fullerene as SET island material which leads to smaller value of the leakage current. Moreover, island length and the number of islands can affect on co-tunneling and then they tune the current flow in SET.

An Extended Combustion Model for the Aircraft Turbojet Engine

NASA Astrophysics Data System (ADS)

Rotaru, Constantin; Andres-Mihăilă, Mihai; Matei, Pericle Gabriel

2014-08-01

The paper consists in modelling and simulation of the combustion in a turbojet engine in order to find optimal characteristics of the burning process and the optimal shape of combustion chambers. The main focus of this paper is to find a new configuration of the aircraft engine combustion chambers, namely an engine with two main combustion chambers, one on the same position like in classical configuration, between compressor and turbine and the other, placed behind the turbine but not performing the role of the afterburning. This constructive solution could allow a lower engine rotational speed, a lower temperature in front of the first stage of the turbine and the possibility to increase the turbine pressure ratio by extracting the flow stream after turbine in the inner nozzle. Also, a higher thermodynamic cycle efficiency and thrust in comparison to traditional constant-pressure combustion gas turbine engines could be obtained.

Breath-Figure Self-Assembly, a Versatile Method of Manufacturing Membranes and Porous Structures: Physical, Chemical and Technological Aspects

PubMed Central

2017-01-01

The review is devoted to the physical, chemical, and technological aspects of the breath-figure self-assembly process. The main stages of the process and impact of the polymer architecture and physical parameters of breath-figure self-assembly on the eventual pattern are covered. The review is focused on the hierarchy of spatial and temporal scales inherent to breath-figure self-assembly. Multi-scale patterns arising from the process are addressed. The characteristic spatial lateral scales of patterns vary from nanometers to dozens of micrometers. The temporal scale of the process spans from microseconds to seconds. The qualitative analysis performed in the paper demonstrates that the process is mainly governed by interfacial phenomena, whereas the impact of inertia and gravity are negligible. Characterization and applications of polymer films manufactured with breath-figure self-assembly are discussed. PMID:28813026

Training of goal directed arm movements with motion interactive video games in children with cerebral palsy - a kinematic evaluation.

PubMed

Sandlund, Marlene; Domellöf, Erik; Grip, Helena; Rönnqvist, Louise; Häger, Charlotte K

2014-10-01

The main aim of this study was to evaluate the quality of goal-directed arm movements in 15 children with cerebral palsy (CP) following four weeks of home-based training with motion interactive video games. A further aim was to investigate the applicability and characteristics of kinematic parameters in a virtual context in comparison to a physical context. Kinematics and kinetics were captured while the children performed arm movements directed towards both virtual and physical targets. The children's movement precision improved, their centre of pressure paths decreased, as did the variability in maximal shoulder angles when reaching for virtual objects. Transfer to a situation with physical targets was mainly indicated by increased movement smoothness. Training with motion interactive games seems to improve arm motor control in children with CP. The results highlight the importance of considering both the context and the task itself when investigating kinematic parameters.

Study on the electromagnetic radiation characteristics of discharging excimer laser system

NASA Astrophysics Data System (ADS)

Zhao, Duliang; Liang, Xu; Fang, Xiaodong; Wang, Qingsheng

2016-10-01

Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

Characteristics and outcomes of America's lowest-performing hospitals: an analysis of acute myocardial infarction hospital care in the United States.

PubMed

Popescu, Ioana; Werner, Rachel M; Vaughan-Sarrazin, Mary S; Cram, Peter

2009-05-01

Studies suggest that most hospitals now have relatively high adherence with recommended acute myocardial infarction (AMI) process measures. Little is known about hospitals with consistently poor adherence with AMI process measures and whether these hospitals also have increased patient mortality. We conducted a retrospective study of 2761 US hospitals reporting AMI process measures to the Center for Medicare and Medicaid Services Hospital Compare database during 2004 to 2006 that could be linked to 2005 Medicare Part A data. The main outcome measures were hospitals' combined compliance with 5 AMI measures (aspirin and beta-blocker on admission and discharge and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use at discharge for patients with left ventricular dysfunction) and risk-adjusted 30-day mortality for 2005. We stratified hospitals into those with low AMI adherence (ranked in the lowest decile for AMI adherence for 3 consecutive years [2004-2006, n=105]), high adherence (ranked in the top decile for 3 consecutive years [n=63]), and intermediate adherence (all others [n=2593]). Mean AMI performance varied significantly across low-, intermediate-, and high-performing hospitals (mean score, 68% versus 92% versus 99%, P<0.001). Low-performing hospitals were more likely than intermediate- and high-performing hospitals to be safety-net providers (19.2% versus 11.0% versus 6.4%; P=0.005). Low-performing hospitals had higher unadjusted 30-day mortality rates (23.6% versus 17.8% versus 14.9%; P<0.001). These differences persisted after adjustment for patient characteristics (16.3% versus 16.0% versus 15.7%; P=0.02). Consistently low-performing hospitals differ substantially from other US hospitals. Targeting quality improvement efforts toward these hospitals may offer an attractive opportunity for improving AMI outcomes.

Relationship between quality of care and choice of clinical computing system: retrospective analysis of family practice performance under the UK's quality and outcomes framework

PubMed Central

Kontopantelis, Evangelos; Buchan, Iain; Reeves, David; Checkland, Kath; Doran, Tim

2013-01-01

Objectives To investigate the relationship between performance on the UK Quality and Outcomes Framework pay-for-performance scheme and choice of clinical computer system. Design Retrospective longitudinal study. Setting Data for 2007–2008 to 2010–2011, extracted from the clinical computer systems of general practices in England. Participants All English practices participating in the pay-for-performance scheme: average 8257 each year, covering over 99% of the English population registered with a general practice. Main outcome measures Levels of achievement on 62 quality-of-care indicators, measured as: reported achievement (levels of care after excluding inappropriate patients); population achievement (levels of care for all patients with the relevant condition) and percentage of available quality points attained. Multilevel mixed effects multiple linear regression models were used to identify population, practice and clinical computing system predictors of achievement. Results Seven clinical computer systems were consistently active in the study period, collectively holding approximately 99% of the market share. Of all population and practice characteristics assessed, choice of clinical computing system was the strongest predictor of performance across all three outcome measures. Differences between systems were greatest for intermediate outcomes indicators (eg, control of cholesterol levels). Conclusions Under the UK's pay-for-performance scheme, differences in practice performance were associated with the choice of clinical computing system. This raises the question of whether particular system characteristics facilitate higher quality of care, better data recording or both. Inconsistencies across systems need to be understood and addressed, and researchers need to be cautious when generalising findings from samples of providers using a single computing system. PMID:23913774

Enhanced sequential reaction time task performance in a rat model of mesial temporal lobe epilepsy with classic hippocampal sclerosis.

PubMed

Will, Johanna L; Eckart, Moritz T; Rosenow, Felix; Bauer, Sebastian; Oertel, Wolfgang H; Schwarting, Rainer K W; Norwood, Braxton A

2013-06-15

The human serial reaction time task (SRTT) has widely been used to study the neural basis of implicit learning. It is well documented, in both human and animal studies, that striatal dopaminergic processes play a major role in this task. However, findings on the role of the hippocampus - which is mainly associated with declarative memory - in implicit learning and performance are less univocal. We used a SRTT to evaluate implicit learning and performance in rats with perforant pathway stimulation-induced hippocampal neuron loss; a clinically-relevant animal model of mesial temporal lobe epilepsy (MTLS-HS). As has been previously reported for the Sprague-Dawley strain, 8h of continuous stimulation in male Wistar rats reliably induced widespread neuron loss in areas CA3 and CA1 with a characteristic sparing of CA2 and the granule cells. Histological analysis revealed that hippocampal volume was reduced by an average of 44%. Despite this severe hippocampal injury, rats showed superior performance in our instrumental SRTT, namely shorter reaction times, and without a loss in accuracy, especially during the second half of our 16-days testing period. These results demonstrate that a hippocampal lesion can improve performance in a rat SRTT, which is probably due to enhanced instrumental performance. In line with our previous findings based on ibotenic-acid induced hippocampal lesion, these data support the hypothesis that loss or impairment of hippocampal function can enhance specific task performance, especially when it is dependent on procedural (striatum-dependent) mechanisms with minimal spatial requirements. As the animal model used here exhibits the defining characteristics of MTLE-HS, these findings may have implications for the study and management of patients with MTLE. Copyright © 2013 Elsevier B.V. All rights reserved.

Psychosocial work characteristics predicting daytime sleepiness in day and shift workers.

PubMed

Takahashi, Masaya; Nakata, Akinori; Haratani, Takashi; Otsuka, Yasumasa; Kaida, Kosuke; Fukasawa, Kenji

2006-01-01

Characteristics of work organization other than working time arrangements may contribute importantly to daytime sleepiness. The present study was designed to identify the psychosocial factors at work that predict daytime sleepiness in a sample of day and shift workers. Participants working at a pulp and chemical factory completed an annual questionnaire regarding psychosocial factors at work using the U.S. National Institute for Occupational Safety and Health Generic Job Stress Questionnaire (i.e., quantitative workload, variance in workload, job control, support from supervisor, coworkers, or family/friends, job satisfaction, and depressive symptoms), as well as daytime sleepiness (through the Epworth Sleepiness Scale [ESS]) and sleep disturbances for three years starting in 2002 (response rates, 94.6-99.0%). The present analysis included 55 day workers (11 women) and 57 shift workers (all men) who participated in all three years of the study, worked under the same work schedule throughout the study period, and had no missing data on any of the daytime sleep items. A repeated-measures analysis of covariance (ANCOVA) was used to test the effects of work schedule (day vs. shift work) and psychosocial factors at work in 2002 on the ESS scores in subsequent years, with sleep duration, insomnia symptoms, chronic diseases, and sleepiness levels at baseline as covariates. Given significant and near-significant interactions of work schedules with psychosocial factor or study year, the ANCOVA, with the factors of psychosocial work characteristics and study year, was performed by type of work schedule. The results indicated a significant main effect of psychosocial work characteristics (p = 0.010, partial eng2 = 0.14) and an almost significant main effect of study year (p = 0.067, partial eng2 = 0.06) and interaction between psychosocial work characteristics and study year (p = 0.085, partial eng2 = 0.06) for variance in workload among the day work group. The day workers reporting high variance in workload in 2002 exhibited significantly higher ESS scores in 2003 and 2004 than did those reporting low variance in workload. The ANCOVA for the shift work group showed a main effect of psychosocial work characteristics for job satisfaction (p = 0.026, partial eng2 = 0.10) and depressive symptoms (p = 0.094, partial eng2 = 0.06) with the interaction between psychosocial work characteristics and study year for job satisfaction (p = 0.172, partial eng2 = 0.04) and depressive symptoms (p = 0.035, partial eng2 = 0.07). The shift workers with low job satisfaction and high symptoms of depression in 2002 showed significantly greater ESS scores in 2003 and/or 2004 than did those with opposite characteristics. These results may suggest a potential predictive value of variance in workload for day workers as well as job satisfaction and depressive symptoms for shift workers with respect to daytime sleepiness. The present findings may imply that redesigning these aspects of work environment would be of help in managing daytime sleepiness.

Tools for detecting insect semiochemicals: a review.

PubMed

Brezolin, Alexandra Nava; Martinazzo, Janine; Muenchen, Daniela Kunkel; de Cezaro, Alana Marie; Rigo, Aline Andressa; Steffens, Clarice; Steffens, Juliana; Blassioli-Moraes, Maria Carolina; Borges, Miguel

2018-07-01

Semiochemicals are chemical compounds that are released by many species as a means of intra- and interspecific communication. Insects have extremely advanced olfactory systems; indeed, they rely on smell when performing many of their main behaviors, such as oviposition, breeding, prey location, and defense. This characteristic of insects implies that semiochemicals could be used for various applications, including in agriculture, where they could be employed along with other tools to control pest insects. The aim of this review is to present the main techniques used and the state of the art in the detection of semiochemicals, focusing on pheromones. In addition to the traditional methods of identifying semiochemicals, such as gas chromatography coupled to a high-resolution detection mode (e.g., flame ionization (FID), electron capture (ECD), photoionization (PID), or mass spectrometry (MS)), other tools are addressed in this review, including sensors and biosensors. While these new technologies may be used under laboratory conditions to improve or complement technologies that are already being used, they are mainly intended for use as new agricultural tools for detecting and controlling pest insects in the field.

Hybrid-PIC simulation of sputtering product distribution in a Hall thruster

NASA Astrophysics Data System (ADS)

Cao, Xifeng; Hang, Guanrong; Liu, Hui; Meng, Yingchao; Luo, Xiaoming; Yu, Daren

2017-10-01

Hall thrusters have been widely used in orbit correction and the station-keeping of geostationary satellites due to their high specific impulse, long life, and high reliability. During the operating life of a Hall thruster, high-energy ions will bombard the discharge channel and cause serious erosion. As time passes, this sputtering process will change the macroscopic surface morphology of the discharge channel, especially near the exit, thus affecting the performance of the thruster. Therefore, it is necessary to carry out research on the motion of the sputtering products and erosion process of the discharge wall. To better understand the moving characteristics of sputtering products, based on the hybrid particle-in-cell (PIC) numerical method, this paper simulates the different erosion states of the thruster discharge channel in different moments and analyzes the moving process of different particles, such as B atoms and B+ ions. In this paper, the main conclusion is that B atoms are mainly produced on both sides of the channel exit, and B+ ions are mainly produced in the middle of the channel exit. The ionization rate of B atoms is approximately 1%.

Characteristics of tip-leakage flow in an axial fan

NASA Astrophysics Data System (ADS)

Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol

2014-11-01

An axial fan with a shroud generates complicated vortical structures by the interaction of the axial flow with the fan blades and shroud near the blade tips. Large eddy simulation (LES) is performed for flow through a forward-swept axial fan, operating at the design condition of Re = 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model (Lee et al. 2010) is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame (Kim & Choi 2006) is adopted for the present simulation. It is found that two vortical structures are formed near the blade tip: the main tip leakage vortex (TLV) and the auxiliary TLV. The main TLV is initiated near the leading edge, develops downstream, and impinges on the pressure surface of the next blade, where the pressure fluctuations and turbulence intensity become high. On the other hand, the auxiliary TLV is initiated at the aft part of the blade but is relatively weak such that it merges with the main TLV. Supported by the KISTI Supercomputing Center (KSC-2014-C2-014).

A Procedure for Determining Tire-Road Friction Characteristics Using a Modification of the Magic Formula Based on Experimental Results

PubMed Central

Pérez, Javier; Velasco, Juan M.; Guerra, Antonio J.; Hernández, Pedro

2018-01-01

Knowledge of tire-road friction characteristics is essential for the proper performance of most relevant vehicle active safety systems. Therefore, its determination is necessary to improve the effectiveness of these systems and to avoid or reduce the consequences of traffic accidents. For this reason, there is a great deal of literature concerning methods and devices for measuring and modeling tire-road friction. Most of these methods have focused on determining the road friction resistance, taking only road composition and making measurements in wet conditions into account. However, friction forces are also dependent on the tire type, since the contact is established between the tire and the road in real driving conditions. Thus, the type and characteristics of the tire have to be considered in the study of the interaction between the vehicle and the road. The aim of this work is to unify the study of the friction coefficient, taking into consideration the two existing bodies involved in the contact, i.e., the tire and road and the main factors that influence the forces in the contact. To this end, a modification of the Pacejka Magic Formula is proposed to include the effects of the main parameters that influence the contact, such as road composition and its state, tire type, vehicle speed, and slip between the tire and the road. To do so, real tests have been conducted on several roads and with different operating conditions. As a result, a more accurate tire-road friction model has been obtained. PMID:29562623

A Procedure for Determining Tire-Road Friction Characteristics Using a Modification of the Magic Formula Based on Experimental Results.

PubMed

Cabrera, Juan A; Castillo, Juan J; Pérez, Javier; Velasco, Juan M; Guerra, Antonio J; Hernández, Pedro

2018-03-17

Knowledge of tire-road friction characteristics is essential for the proper performance of most relevant vehicle active safety systems. Therefore, its determination is necessary to improve the effectiveness of these systems and to avoid or reduce the consequences of traffic accidents. For this reason, there is a great deal of literature concerning methods and devices for measuring and modeling tire-road friction. Most of these methods have focused on determining the road friction resistance, taking only road composition and making measurements in wet conditions into account. However, friction forces are also dependent on the tire type, since the contact is established between the tire and the road in real driving conditions. Thus, the type and characteristics of the tire have to be considered in the study of the interaction between the vehicle and the road. The aim of this work is to unify the study of the friction coefficient, taking into consideration the two existing bodies involved in the contact, i.e., the tire and road and the main factors that influence the forces in the contact. To this end, a modification of the Pacejka Magic Formula is proposed to include the effects of the main parameters that influence the contact, such as road composition and its state, tire type, vehicle speed, and slip between the tire and the road. To do so, real tests have been conducted on several roads and with different operating conditions. As a result, a more accurate tire-road friction model has been obtained.

Profile of patients with uveitis referred to a multidisciplinary unit in northern Spain.

PubMed

Fanlo, P; Heras, H; Pérez, D; Tiberio, G; Espinosa, G; Adan, A

2017-05-01

To describe the main characteristics of a cohort of patients with uveitis referred to a multidisciplinary unit in northern Spain. Retrospective analysis of clinical records of patients evaluated in the Multidisciplinary Unit of the Navarra Hospital Complex from the period January 2010 until March 2015. An analysis was performed on the demographic characteristics, origin, types of uveitis, laterality, and aetiology. The present series was also compared with 2 previous series from Castilla y León and Barcelona. A total of 500 patients were identified, with a mean age of 47.9±16.4 years, with 50% women. The most frequent type of uveitis was anterior uveitis (65.4%), followed by posterior uveitis (17.6%), panuveitis (15.2%), and intermediate uveitis (1.8%). The origin was unclassifiable in 31.2%, followed by non-infectious systemic disease in 29.2%. Ankylosing spondylitis was the most frequent cause in 10.8% of patients, followed by herpes infection in 9.2%, and toxoplasmosis in 7.8%, respectively. Compared with the 2other cohorts, the present cohort showed a higher proportion of unilateral anterior uveitis. Furthermore, the patients from the Navarra series had a higher prevalence of unilateral and idiopathic uveitis compared to the series from Barcelona. The main characteristics of the present cohort of patients with uveitis are similar to those of patients from other regions of our country. Unilateral anterior uveitis and idiopathic uveitis were the most frequent in our series. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Methods, procedures, and contextual characteristics of health technology assessment and health policy decision making: comparison of health technology assessment agencies in Germany, United Kingdom, France, and Sweden.

PubMed

Schwarzer, Ruth; Siebert, Uwe

2009-07-01

The objectives of this study were (i) to develop a systematic framework for describing and comparing different features of health technology assessment (HTA) agencies, (ii) to identify and describe similarities and differences between the agencies, and (iii) to draw conclusions both for producers and users of HTA in research, policy, and practice. We performed a systematic literature search, added information from HTA agencies, and developed a conceptual framework comprising eight main domains: organization, scope, processes, methods, dissemination, decision, implementation, and impact. We grouped relevant items of these domains in an evidence table and chose five HTA agencies to test our framework: DAHTA@DIMDI, HAS, IQWiG, NICE, and SBU. Item and domain similarity was assessed using the percentage of identical characteristics in pairwise comparisons across agencies. RESULTS were interpreted across agencies by demonstrating similarities and differences. Based on 306 included documents, we identified 90 characteristics of eight main domains appropriate for our framework. After applying the framework to the five agencies, we were able to show 40 percent similarities in "dissemination," 38 percent in "scope," 35 percent in "organization," 29 percent in "methods," 26 percent in "processes," 23 percent in "impact," 19 percent in "decision," and 17 percent in "implementation." We found considerably more differences than similarities of HTA features across agencies and countries. Our framework and comparison provides insights and clarification into the need for harmonization. Our findings could serve as descriptive database facilitating communication between producers and users.

Economic Culture and Trading Behaviors in Information Markets

ERIC Educational Resources Information Center

Alhayyan, Khalid N.

2012-01-01

There are four main components for influencing traders' behaviors in an information market context: trader characteristics, organizational characteristics, market design, and external information. This dissertation focuses on investigating the impact of individual trader characteristics on trading behaviors. Two newly-developed constructs,…

Combustion Stability Characteristics of the Project Morpheus Liquid Oxygen / Liquid Methane Main Engine

NASA Technical Reports Server (NTRS)

Melcher, John C.; Morehead, Robert L.

2014-01-01

The project Morpheus liquid oxygen (LOX) / liquid methane (LCH4) main engine is a Johnson Space Center (JSC) designed 5,000 lbf-thrust, 4:1 throttling, pressure-fed cryogenic engine using an impinging element injector design. The engine met or exceeded all performance requirements without experiencing any in- ight failures, but the engine exhibited acoustic-coupled combustion instabilities during sea-level ground-based testing. First tangential (1T), rst radial (1R), 1T1R, and higher order modes were triggered by conditions during the Morpheus vehicle derived low chamber pressure startup sequence. The instability was never observed to initiate during mainstage, even at low power levels. Ground-interaction acoustics aggravated the instability in vehicle tests. Analysis of more than 200 hot re tests on the Morpheus vehicle and Stennis Space Center (SSC) test stand showed a relationship between ignition stability and injector/chamber pressure. The instability had the distinct characteristic of initiating at high relative injection pressure drop at low chamber pressure during the start sequence. Data analysis suggests that the two-phase density during engine start results in a high injection velocity, possibly triggering the instabilities predicted by the Hewitt stability curves. Engine ignition instability was successfully mitigated via a higher-chamber pressure start sequence (e.g., 50% power level vs 30%) and operational propellant start temperature limits that maintained \\cold LOX" and \\warm methane" at the engine inlet. The main engine successfully demonstrated 4:1 throttling without chugging during mainstage, but chug instabilities were observed during some engine shutdown sequences at low injector pressure drop, especially during vehicle landing.

Are RA patients from a non-endemic HCV population screened for HCV? A cross-sectional analysis of three different settings.

PubMed

Skinner-Taylor, Cassandra Michelle; Erhard-Ramírez, Alejandro; Garza-Elizondo, Mario Alberto; Esquivel-Valerio, Jorge Antonio; Abud-Mendoza, Carlos; Martínez-Martínez, Marco Ulises; Vega-Morales, David; Arana-Guajardo, Ana

In Mexico, other risk factors are associated with hepatitis C virus (HCV): prior heroin users, living alone, widower, and northern region residence. Rheumatoid arthritis (RA) patients are considered immunosuppressed and HCV testing is recommended before treatment. The aim of the study was to describe the characteristics of HCV testing in RA patients in three different medical care settings in a non-endemic area. A retrospective observational study was performed using medical records from 960 RA patients describing the indications for HCV testing. The test was performed in 28.6% and the HCV overall frequency was 0.36%. Population characteristics were not associated with an increased risk of HCV infection; therefore, anti-HCV positivity was low. The main reason for testing was before starting biological agents. Due to the low pre-test probability, testing for HCV infection should be personalized; i.e., according to disease prevalence in a particular geographical location and the individual risk factors. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

Physical and Chemical Properties of Sintering Red Mud and Bayer Red Mud and the Implications for Beneficial Utilization

PubMed Central

Wang, Ping; Liu, Dong-Yan

2012-01-01

Performances of two common types of red mud, Bayer red mud and Sintering red mud, were investigated in this research. Their compositions, mechanical properties and microstructure characterization were measured through XRD, TG and SEM analysis. Their shear strength, particle size, density and hydraulic characteristics also had been performed. Huge differences between the basic mineral types of these two kinds of red mud also can be found. The comparison of compositions shows that CaCO3 content in Sintering red mud is higher, Bayer red mud has more hazardous elements such as As, Pb and Hg and both have a high concentration of radioactivity. The micro particle of Bayer red mud is finer and more disperse, but the Sintering red mud has higher shear strength. Combining the TG and hydraulic characteristics analysis, it can be shown that Bayer red mud has higher value of water content and Sintering red mud has higher hydraulic conductivity. The paper then illustrates that Sintering red mud can become the main filling material of supporting structure of red mud stocking yard. Bayer red mud has a high reuse value and also can be used as a mixing material of masonry mortar.

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and power processing unit (PPU) design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through Simulation Program with Integrated Circuit Emphasis modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

The Impact of Harness Impedance on Hall Thruster Discharge Oscillations

NASA Technical Reports Server (NTRS)

Pinero, Luis R.

2017-01-01

Hall thrusters exhibit characteristic discharge voltage and current oscillations during steady-state operation. The lower frequency breathing-mode current oscillations are inherent to each thruster and could impact thruster operation and PPU design. The design of the discharge output filter, in particular, the output capacitor is important because it supplies the high peak current oscillations that the thruster demands. However, space-rated, high-voltage capacitors are not readily available and can have significant mass and volume. So, it is important for a PPU designer to know what is the minimum amount of capacitance required to operate a thruster. Through SPICE modeling and electrical measurements on the Hall Effect Rocket with Magnetic Shielding (HERMeS) thruster, it was shown that the harness impedance between the power supply and the thruster is the main contributor towards generating voltage ripple at the thruster. Also, increasing the size of the discharge filter capacitor, as previously implemented during thruster tests, does not reduce the voltage oscillations. The electrical characteristics of the electrical harness between the discharge supply and the thruster is crucial to system performance and could have a negative impact on performance, life and operation.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment.

PubMed

Wang, Hui-Ling; Yang, Zhao-Hui; Huang, Jing; Wang, Li-Ke; Gou, Cheng-Liu; Yan, Jing-Wu; Yang, Jian

2014-01-01

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm(3) had the best drying performance at each level of temperature, which could save 35-45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm(3) was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

Surface-emitting mid-infrared quantum cascade lasers with high-contrast photonic crystal resonators.

PubMed

Xu, Gangyi; Colombelli, Raffaele; Braive, Remy; Beaudoin, Gregoire; Le Gratiet, Luc; Talneau, Anne; Ferlazzo, Laurence; Sagnes, Isabelle

2010-05-24

We have developed surface-emitting single-mode quantum cascade lasers which employ high-contrast photonic-crystal resonators. The devices operate on band-edge states of the photonic band-structure. The mode profile and polarization characteristics of the band-edge modes are calculated by three-dimensional finite-difference time-domain simulation. Experimentally, the spectral properties, the far-field patterns, and the polarization characteristics of the lasers are determined and compared with simulations. The good agreement between the simulations and the experiments confirms that the hexapolar mode at the Gamma-point band-edge gives rise to lasing. By using a novel and advanced fabrication method, deep and vertical PhC holes are fabricated with no metal redeposition on the sidewalls, which improves the laser performance with respect to the current status. The angular of the output beam is approximately 15 masculine, and the side mode suppression ratio of the single mode emission is about 25 dB. The threshold current density at 78 K and the maximum operation temperature are 7.6 kA/cm2 and 220 K, respectively. The performance is mainly limited by the loss induced by surface plasmon waveguide, which can be overcome by using an optimized dielectric waveguide structure.

Management of pancreatic cancer in the elderly.

PubMed

Higuera, Oliver; Ghanem, Ismael; Nasimi, Rula; Prieto, Isabel; Koren, Laura; Feliu, Jaime

2016-01-14

Currently, pancreatic adenocarcinoma mainly occurs after 60 years of age, and its prognosis remains poor despite modest improvements in recent decades. The aging of the population will result in a rise in the incidence of pancreatic adenocarcinoma within the next years. Thus, the management of pancreatic cancer in the elderly population is gaining increasing relevance. Older cancer patients represent a heterogeneous group with different biological, functional and psychosocial characteristics that can modify the usual management of this disease, including pharmacokinetic and pharmacodynamic changes, polypharmacy, performance status, comorbidities and organ dysfunction. However, the biological age, not the chronological age, of the patient should be the limiting factor in determining the most appropriate treatment for these patients. Unfortunately, despite the increased incidence of this pathology in older patients, there is an underrepresentation of these patients in clinical trials, and the management of older patients is thus determined by extrapolation from the results of studies performed in younger patients. In this review, the special characteristics of the elderly, the multidisciplinary management of localized and advanced ductal adenocarcinoma of the pancreas and the most recent advances in the management of this condition will be discussed, focusing on surgery, chemotherapy, radiation and palliative care.

Construction and performance characteristics of new ion selective electrodes based on carbon nanotubes for determination of meclofenoxate hydrochloride.

PubMed

El-Nashar, Rasha M; Abdel Ghani, Nour T; Hassan, Sherif M

2012-06-12

This work offers construction and comparative evaluation the performance characteristics of conventional polymer (I), carbon paste (II) and carbon nanotubes chemically modified carbon paste ion selective electrodes (III) for meclofenoxate hydrochloride are described. These electrodes depend mainly on the incorporation of the ion pair of meclofenoxate hydrochloride with phosphomolybdic acid (PMA) or phosphotungestic acid (PTA). They showed near Nernestian responses over usable concentration range 1.0 × 10(-5) to 1.0 × 10(-2)M with slopes in the range 55.15-59.74 mV(concentrationdecade)(-1). These developed electrodes were fully characterized in terms of their composition, response time, working concentration range, life span, usable pH and temperature range. The electrodes showed a very good selectivity for Meclo with respect to a large number of inorganic cations, sugars and in the presence of the degradation product of the drug (p-chloro phenoxy acetic acid). The standard additions method was applied to the determination of MecloCl in pure solution, pharmaceutical preparations and biological samples. Dissolution testing was also applied using the proposed sensors. Copyright © 2011 Elsevier B.V. All rights reserved.

78 FR 18988 - Establishing the Performance Characteristics of In Vitro Diagnostic Devices for the Detection of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-28

...] Establishing the Performance Characteristics of In Vitro Diagnostic Devices for the Detection of Antibodies to... announcing the availability of the guidance entitled ``Establishing the Performance Characteristics of In... document entitled ``Establishing the Performance Characteristics of In Vitro Diagnostic Devices for the...

On the performance of satellite precipitation products in riverine flood modeling: A review

NASA Astrophysics Data System (ADS)

Maggioni, Viviana; Massari, Christian

2018-03-01

This work is meant to summarize lessons learned on using satellite precipitation products for riverine flood modeling and to propose future directions in this field of research. Firstly, the most common satellite precipitation products (SPPs) during the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM) eras are reviewed. Secondly, we discuss the main errors and uncertainty sources in these datasets that have the potential to affect streamflow and runoff model simulations. Thirdly, past studies that focused on using SPPs for predicting streamflow and runoff are analyzed. As the impact of floods depends not only on the characteristics of the flood itself, but also on the characteristics of the region (population density, land use, geophysical and climatic factors), a regional analysis is required to assess the performance of hydrologic models in monitoring and predicting floods. The performance of SPP-forced hydrological models was shown to largely depend on several factors, including precipitation type, seasonality, hydrological model formulation, topography. Across several basins around the world, the bias in SPPs was recognized as a major issue and bias correction methods of different complexity were shown to significantly reduce streamflow errors. Model re-calibration was also raised as a viable option to improve SPP-forced streamflow simulations, but caution is necessary when recalibrating models with SPP, which may result in unrealistic parameter values. From a general standpoint, there is significant potential for using satellite observations in flood forecasting, but the performance of SPP in hydrological modeling is still inadequate for operational purposes.

Public health case studies in diabetes prevention and control: innovation, partnerships, and funding.

PubMed

Davis, Mary V; Cannon, Margaret M; Reese, April; Lovette, Beth; Porterfield, Deborah S

2011-01-01

In 2006, we conducted case studies of 4 North Carolina local health departments (LHDs) that scored highly on an index of diabetes prevention and control performance, to explore characteristics that may serve as barriers or facilitators of diabetes prevention and control services. Case studies involving in-depth interviews were conducted at 4 LHDs. Sites were selected on the basis of 2 variables, known external funding for diabetes services and population size, that were associated with performance in diabetes prevention and control in a 2005 survey of all North Carolina LHDs. Fourteen interviews (individual and group) were conducted among 17 participants from the 4 LHDs. The main outcome measures were LHD characteristics that facilitate or hinder the performance of diabetes programs and services. Interviews revealed that all 4 high-performing LHDs had received some sort of funding from a source external to the LHD. Case study participants indicated that barriers to additional service delivery included low socioeconomic status of the population and lack of financial resources. Having a diabetes self-management education program that was recognized by the American Diabetes Association appeared to be a facilitator of diabetes services provision. Other facilitators were leadership and staff commitment, which appeared to facilitate the leveraging of partnerships and funding opportunities, leading to enhanced service delivery. The small number of LHDs participating in the study and the cross-sectional study design were limitations. Leadership, staff commitment, partnership leveraging, and funding appear to be associated with LHD performance in diabetes prevention and control services. These factors should be further studied in future public health systems and services research.

A simulation investigation of scout/attack helicopter directional control requirements for hover and low-speed tasks

NASA Technical Reports Server (NTRS)

Bivens, Courtland C.; Guercio, Joseph G.

1987-01-01

A piloted simulator experiment was conducted to investigate directional axis handling qualities requirements for low speed and hover tasks performed by a Scout/Attack helicopter. Included were the directional characteristics of various candidate light helicopter family configurations. Also, the experiment focused on conventional single main/tail rotor configurations of the OH-58 series aircraft, where the first-order yaw-axis dynamic effects that contributed to the loss of tail rotor control were modeled. Five pilots flew 22 configurations under various wind conditions. Cooper-Harper handling quality ratings were used as the primary measure of merit of each configuration. The results of the experiment indicate that rotorcraft configurations with high directional gust sensitivity require greater minimum yaw damping to maintain satisfactory handling qualities during nap-of-the-Earth flying tasks. It was also determined that both yaw damping and control response are critical handling qualities parameters in performing the air-to-air target acquisition and tracking task. Finally, the lack of substantial yaw damping and larger values of gust sensitivity increased the possibility of loss of directional control at low airspeeds for the single main/tail rotor configurations.

Main competences and skills to perform Essential Public Health Operations, offered by Schools of Public Health in four European countries: a short pilot report.

PubMed

Otok, Robert; Foldspang, Anders

2016-07-01

To consider the stage of implementation of main competences and EPHO skills in selected schools of public health in four European countries-France, Poland, Portugal, and the UK. By use of visual analogue scales (VAS) ranging 1-5, the leads of three schools of public health (SPH) in each of the four countries, France, Poland, Portugal and the UK, reported the strength of intellectual and practical competences as well as skills to perform essential public health operations (EPHOs), offered by their education and training programmes. The self-reports indicated substantial coverage of the multidimensional public health discipline. Each country representation had its overall characteristic profile, and there was found noteworthy within-country as well as between-country variation. The schools should meet the challenge of establishing collaborative networks, which will be important for public health strategy making and implementation, for shaping a coherent public health profession, and thus ultimately for population health. This pilot report should be followed up by more systematically penetrating and comprehensive analyses to identify met and unmet needs in public health education and training.

Benchmark for Numerical Models of Stented Coronary Bifurcation Flow.

PubMed

García Carrascal, P; García García, J; Sierra Pallares, J; Castro Ruiz, F; Manuel Martín, F J

2018-09-01

In-stent restenosis ails many patients who have undergone stenting. When the stented artery is a bifurcation, the intervention is particularly critical because of the complex stent geometry involved in these structures. Computational fluid dynamics (CFD) has been shown to be an effective approach when modeling blood flow behavior and understanding the mechanisms that underlie in-stent restenosis. However, these CFD models require validation through experimental data in order to be reliable. It is with this purpose in mind that we performed particle image velocimetry (PIV) measurements of velocity fields within flows through a simplified coronary bifurcation. Although the flow in this simplified bifurcation differs from the actual blood flow, it emulates the main fluid dynamic mechanisms found in hemodynamic flow. Experimental measurements were performed for several stenting techniques in both steady and unsteady flow conditions. The test conditions were strictly controlled, and uncertainty was accurately predicted. The results obtained in this research represent readily accessible, easy to emulate, detailed velocity fields and geometry, and they have been successfully used to validate our numerical model. These data can be used as a benchmark for further development of numerical CFD modeling in terms of comparison of the main flow pattern characteristics.

FLPP IXV Re-Entry Vehicle, Supersonic Charectisation Based on DNW SST Wind Tunnel Tests and CFD

NASA Astrophysics Data System (ADS)

Kapteijn, C.; Maseland, H.; Chiarelli, C.; Mareschi, V.; Tribot, J.-P.; Binetti, P.; Walloscheck, T.

2009-01-01

The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues for controlled re-entry, while supporting the future generation launchers and to improve in general European capabilities in the strategic field of atmospheric re-entry for future space transportation, exploration and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on- ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re- entry system, integrating the critical re- entry technologies at the system level. In particular, the IXV shall demonstrate system integrated key technologies such as lifting flight control by means of aerodynamic surfaces that are one of the main primary objectives of the experimental investigation. Lifting and aerodynamic controlled re-entry represents a significant capability advancement with respect to the ballistic re-entry of capsules like the ARD. Since hypersonic aerodynamics is essentially different from supersonic aerodynamics, the current mission is to perform an atmospheric re-entry in combination with a safe recovery the in supersonic flight regime. However, mission extension to trimmed transonic flight is under consideration based on a preliminary analysis of the aerodynamic characteristics of the IXV configuration. Since the beginning of the IXV project, an aerodynamic data base (AEDB) has been built up and continuously updated integrating the additional information mainly provided by means of CFD (ie: Euler and Navier-Stokes) and lately also by means of WTTs. This AEDB serves for flying qualities analysis and for re-entry simulations. During the development phase B2/C1, the effectiveness of the control surfaces and their impact on te vehicle's aerodynamic forces in the supersonic regime is measured for a number of discrete deflection settings in the Super-Sonic wind Tunnel (SST) of DNW. Enabling an improved understanding of the measured aerodynamic characteristics, complementary computations were performed by Thales Alenia Space. The complete set of data was analyzed and compared enabling a consolidation of the nominal aerodynamic and aerodynamic uncertainties as well. The paper presents the main objectives of the supersonic characterisation of IXV including WTTs, and the main outcomes of the current data comparisons.

Chiropractors' characteristics associated with physician referrals: results from a survey of Canadian doctors of chiropractic.

PubMed

Blanchette, Marc-André; Rivard, Michèle; Dionne, Clermont E; Cassidy, J David

2015-01-01

The purpose of this study was to identify characteristics of Canadian doctors of chiropractic (DCs) associated with the number of patients referred by medical doctors (MDs). Secondary data analyses were performed on the 2011 cross-sectional survey of the Canadian Chiropractic Resources Databank. The Canadian Chiropractic Resources Databank survey included 81 questions about the practice of DCs. Of the 6533 mailed questionnaires, 2529 (38.7%) were returned and 489 did not meet our inclusion criteria. Our analyzed sample included 2040 respondents. Bivariate analyses were conducted between predetermined potential predictors and the annual number of patients referred by MDs, and negative binomial multivariate regression was performed. On average, DCs reported receiving 15.6 (standard deviation, 31.3) patient referrals from MDs per year and nearly one-third did not receive any. The type of clinic (multidisciplinary with MD), the province of practice (Atlantic provinces), the number of treatments provided per week, the number of practicing hours, rehabilitation and sports injuries as the main sector of activity, prescription of exercises, use of heat packs and ultrasound, and the percentage of patients referred to other health care providers were associated with a higher number of MD referrals to DCs. The percentage of patients with somatovisceral conditions, using a particular chiropractic technique (hole in one and Thompson), taking his/her own radiographs, being the client of a chiropractic management service, and considering maintenance/wellness care as a main sector of activity were associated with fewer MD referrals. Canadian DCs who interacted with other health care workers and who focus their practice on musculoskeletal conditions reported more referrals from MDs. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Reliability Analysis of Differential Relay as Main Protection Transformer Using Fuzzy Logic Algorithm

NASA Astrophysics Data System (ADS)

Mulyadi, Y.; Sucita, T.; Sumarto; Alpani, M.

2018-02-01

Electricity supply demand is increasing every year. It makes PT. PLN (Persero) is required to provide optimal customer service and satisfaction. Optimal service depends on the performance of the equipment of the power system owned, especially the transformer. Power transformer is an electrical equipment that transforms electricity from high voltage to low voltage or vice versa. However, in the electrical power system, is inseparable from interference included in the transformer. But, the disturbance can be minimized by the protection system. The main protection transformer is differential relays. Differential relays working system using Kirchoff law where inflows equal outflows. If there are excessive currents that interfere then the relays will work. But, the relay can also experience decreased performance. Therefore, this final project aims to analyze the reliability of the differential relay on the transformer in three different substations. Referring to the standard applied by the transmission line protection officer, the differential relay shall have slope characteristics of 30% in the first slope and 80% in the second slope when using two slopes and 80% when using one slope with an instant time and the corresponding ratio. So, the results obtained on the Siemens differential release have a reliable slope characteristic with a value of 30 on the fuzzy logic system. In a while, ABB a differential relay is only 80% reliable because two experiments are not reliable. For the time, all the differential relays are instant with a value of 0.06 on the fuzzy logic system. For ratios, the differential relays ABB have a better value than others brand with a value of 151 on the fuzzy logic system.

The bioimpedance analysis of a parenchyma of a liver in the conditions of its extensive resection in experiment

NASA Astrophysics Data System (ADS)

Agibalov, D. Y.; Panchenkov, D. N.; Chertyuk, V. B.; Leonov, S. D.; Astakhov, D. A.

2017-01-01

The liver failure which is result of disharmony of functionality of a liver to requirements of an organism is the main reason for unsatisfactory results of an extensive resection of a liver. However, uniform effective criterion of definition of degree of a liver failure it isn’t developed now. One of data acquisition methods about a morfo-functional condition of internals is the bioimpedance analysis (BIA) based on impedance assessment (full electric resistance) of a biological tissue. Measurements of an impedance are used in medicine and biology for the characteristic of physical properties of living tissue, studying of the changes bound to a functional state and its structural features. In experimental conditions we carried out an extensive resection of a liver on 27 white laboratory rats of the Vistar line. The comparative characteristic of data of a bioimpedansometriya in intraoperative and after the operational period with the main existing methods of assessment of a functional condition of a liver was carried out. By results of the work performed by us it is possible to claim that the bioimpedance analysis of a liver on the basis of an invasive bioimpedansometriya allows to estimate morphological features and functional activity of a liver before performance of an extensive resection of a liver. The data obtained during scientific work are experimental justification for use of an impedansometriya during complex assessment of functional reserves of a liver. Preliminary data of clinical approbation at a stage of introduction of a technique speak about rather high informational content of a bioimpedansometriya. The subsequent analysis of efficiency of the invasive bioimpedance analysis of a liver requires further accumulation of clinical data. However even at this stage the method showed the prospect for further use in clinical surgical hepathology.

Defibrillation testing in everyday medical practice during implantable cardioverter defibrillator implantation in France: analysis from the LEADER registry.

PubMed

Sadoul, Nicolas; Defaye, Pascal; Mouton, Elisabeth; Bizeau, Olivier; Dupuis, Jean-Marc; Blangy, Hugues; Delarche, Nicolas; Blanc, Jean-Jacques; Lazarus, Arnaud

2013-11-01

Defibrillation testing (DT) is usually performed during implantable cardioverter defibrillator (ICD) implantation. We conducted a multicentre prospective study to determine the DT procedures used in everyday practice, to compare the characteristics of patients with or without DT, and to compare severe adverse events in these two populations during implantation and follow-up. The LEADER registry enrolled 904 patients included for primo-implantation of a single (n=261), dual (n=230) or triple (n=429) defibrillation system in 42 French centres. Baseline characteristics of patients (62.0 ± 13.5 years; 88% men; primary indication 62%) who underwent ventricular fibrillation (VF) induction (VF induction group, n=810) and those who did not (untested group, n=94, representing 10.4% of the entire study population) revealed that the untested group were older (P<0.01), had a lower left ventricular ejection fraction, a wider QRS complex and a higher New York Heart Association class and were more often implanted for primary prevention (P<0.001 for all). The main reason given for not performing ICD testing was poor haemodynamic condition (59/94). At 1 year, the cumulative survival rate was 95% in tested patients and 85% in untested patients (P<0.001), mainly because of heart failure deaths. There was one sudden cardiac death in the VF induction group and none in the untested group (P=1.000). In this study, more than 10% of ICD patients were implanted without VF induction. Untested patients appeared to be sicker than tested patients, with a more severe long-term outcome, but without any difference in mortality due to arrhythmic events. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

IASI-NG: a new generation of infrared sounders for meteorology and atmospheric composition

NASA Astrophysics Data System (ADS)

Deschamps, A.; Bermudo, F.; Rousseau, S.; Bernard, F.; Pequignot, E.

2016-12-01

IASI-NG is the main payload of the future Metop-SG satellite of the Eumetsat EPS-SG program. This infrared atmospheric sounder generates radiance spectra at high resolution between 645cm-1 and 2760cm-1 and takes benefits from the IASI heritage. As for the first generation, the development of IASI-NG is under CNES responsibility. The first goal of the IASI-NG mission is to support Numerical Weather Prediction (NWP) by improving the estimation of humidity and temperature profiles, especially in the troposphere. To reach this goal, the spectral resolution will be two times better than for IASI first generation, and the radiometric noise will be divided by a factor of two. These performances will enable to support pollution monitoring, climate and atmospheric composition studies as well. CH4 and CO2 columns (but also O3, SO2, CO, NH3, HNO3 concentrations) are some of the products which will be derived from the IASI-NG measurements, in addition to NWP products (such as temperature and water vapor profiles, surface temperature and cloud information). This presentation describes in a first part the main characteristics of the instrument, which allow it to reach this level of performances. The interferometer, developed by Airbus Defense and Space, is based on the Mertz concept and allows to assess the self apodization by a field effect compensation (IASI-NG will be the first mission to implement Mertz Interferometer). In a second part, we present the main performances of the IASI-NG system, in terms of radiometric noise, spectral resolution and geolocation. We describe also the main algorithms which will be used in the ground segment to calibrate the data and correct the instrumental effects. Lastly, we give some information about the status of the project which is currently is the C/D phase and the major milestones in the IASI-NG agenda.

Simulation of dyslexia. How literacy and cognitive skills can help distinguish college students with dyslexia from malingerers

PubMed Central

de Bree, Elise H.; de Jong, Peter F.

2018-01-01

Academic accommodations associated with a diagnosis of dyslexia might be incentives for college students without reading or spelling difficulties to feign dyslexia and obtain the diagnosis unfairly. In the current study we examined malingering practices by comparing the performance of college students instructed to malinger dyslexia (n = 28) to that of students actually diagnosed with dyslexia (n = 16). We also included a control group of students without reading and spelling difficulties (n = 28). The test battery included tasks tapping literacy skills as well as underlying cognitive skills associated with literacy outcomes. These tasks are commonly used in diagnosing dyslexia. We examined patterns in the performance of malingerers across tasks and tested whether malingerers could be identified based on their performance on a limited number of tasks. Results indicated that malingerers scored significantly lower than students with dyslexia on reading and spelling skills; i.e., the core characteristics of dyslexia. Especially reading performance was extremely low and not in line with students’ age and level of education. Findings for underlying cognitive skills were mixed. Overall, malingerers scored lower than students with dyslexia on tasks tapping mainly speed, whereas the two groups did not differ on tasks reflecting mainly accuracy. Based on word and pseudoword reading and letter and digit naming, the three groups could be distinguished with reasonable sensitivity and specificity. In all, results indicate that college students seem to understand on which tasks they should feign dyslexia, but tend to exaggerate difficulties on these tasks to the point where diagnosticians should mistrust performance. PMID:29782515

Analysis of the pump-turbine S characteristics using the detached eddy simulation method

NASA Astrophysics Data System (ADS)

Sun, Hui; Xiao, Ruofu; Wang, Fujun; Xiao, Yexiang; Liu, Weichao

2015-01-01

Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics(CFD) results. Predictions using the detached eddy simulation(DES) turbulence model, which is a combined Reynolds averaged Naviers-Stokes(RANS) and large eddy simulation(LES) model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. Comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics.

Patient characteristics as predictors of primary health care preferences: a systematic literature analysis

PubMed Central

Jung, Hans Peter; Baerveldt, Cor; Olesen, Frede; Grol, Richard; Wensing, Michel

2003-01-01

Abstract Objective To identify associations between various cultural and demographic factors and patients’ primary health care preferences. Search strategy Searches were performed in MEDLINE (1966–December 2000), PsycINFO (1977–May 2001) and Sociological Abstracts (1963–December 2000). Identified papers were checked for more papers. Inclusion criteria Studies with a focus on primary health care or health care in general, asking patients about preferences with regard to health care, reporting quantitative results and examining the relations between specific patient characteristics and patient preferences. Data extraction and synthesis Data were extracted from studies using a scoring form to register what methods were used, which patient characteristics were analysed and which patient characteristics significantly influenced patients’ preferences with regard to different aspects of health care (P < 0.05). Main results A total of 145 studies were included with 2276 comparisons between subgroups of patients. Of all the comparisons, 607 (27%) showed a significant association between patient characteristics and preferences with regard to primary health care. Age and economic status significantly related to patient preferences in 38 and 33% of the comparisons, respectively. Education, health status, family situation, sex, and utilization of health care related significantly to patient preferences in less than 25% of the comparisons. Conclusions This review of the literature showed patient characteristics to be an important determinant of preferences regarding many aspects of primary health care defined as general practice care or health care, in general. All of the patient characteristics examined here showed at least some significant associations with preferences for primary health care. PMID:12752744

Users manual for the Automated Performance Test System (APTS)

NASA Technical Reports Server (NTRS)

Lane, N. E.; Kennedy, R. S.

1990-01-01

The characteristics of and the user information for the Essex Automated Performance Test System (APTS) computer-based portable performance assessment battery are given. The battery was developed to provide a menu of performance test tapping the widest possible variety of human cognitive and motor functions, implemented on a portable computer system suitable for use in both laboratory and field settings for studying the effects of toxic agents and other stressors. The manual gives guidance in selecting, administering and scoring tests from the battery, and reviews the data and studies underlying the development of the battery. Its main emphasis is on the users of the battery - the scientists, researchers and technicians who wish to examine changes in human performance across time or as a function of changes in the conditions under which test data are obtained. First the how to information needed to make decisions about where and how to use the battery is given, followed by the research background supporting the battery development. Further, the development history of the battery focuses largely on the logical framework within which tests were evaluated.

Multilevel microvibration test for performance predictions of a space optical load platform

NASA Astrophysics Data System (ADS)

Li, Shiqi; Zhang, Heng; Liu, Shiping; Wang, Yue

2018-05-01

This paper presents a framework for the multilevel microvibration analysis and test of a space optical load platform. The test framework is conducted on three levels, including instrument, subsystem, and system level. Disturbance source experimental investigations are performed to evaluate the vibration amplitude and study vibration mechanism. Transfer characteristics of space camera are validated by a subsystem test, which allows the calculation of transfer functions from various disturbance sources to optical performance outputs. In order to identify the influence of the source on the spacecraft performance, a system level microvibration measurement test has been performed on the ground. From the time domain analysis and spectrum analysis of multilevel microvibration tests, we concluded that the disturbance source has a significant effect on its installation position. After transmitted through mechanical links, the residual vibration reduces to a background noise level. In addition, the angular microvibration of the platform jitter is mainly concentrated in the rotation of y-axes. This work is applied to a real practical application involving the high resolution satellite camera system.

Handling performance control for hybrid 8-wheel-drive vehicle and simulation verification

NASA Astrophysics Data System (ADS)

Ni, Jun; Hu, Jibin

2016-08-01

In order to improve handling performance of a hybrid 8-Wheel-Drive vehicle, the handling performance control strategy was proposed. For armoured vehicle, besides handling stability in high speed, the minimum steer radius in low speed is also a key tactical and technical index. Based on that, the proposed handling performance control strategy includes 'Handling Stability' and 'Radius Minimization' control modes. In 'Handling Stability' control mode, 'Neutralsteer Radio' is defined to adjust the steering characteristics to satisfy different demand in different speed range. In 'Radius Minimization' control mode, the independent motors are controlled to provide an additional yaw moment to decrease the minimum steer radius. In order to verify the strategy, a simulation platform was built including engine and continuously variable transmission systems, generator and battery systems, independent motors and controllers systems, vehicle dynamic and tyre mechanical systems. The simulation results show that the handling performance of the vehicle can be enhanced significantly, and the minimum steer radius can be decreased by 20% which is significant improvement compared to the common level of main battle armoured vehicle around the world.

Comparison of catalytic converter performance in internal combustion engine fueled with Ron 95 and Ron 97 gasoline

NASA Astrophysics Data System (ADS)

Leman, A. M.; Rahman, Fakhrurrazi; Jajuli, Afiqah; Feriyanto, Dafit; Zakaria, Supaat

2017-09-01

Generating ideal stability between engine performance, fuel consumption and emission is one of the main challenges in the automotive industry. The characteristics of engine combustion and creation of emission might simply change with different types of operating parameters. This study aims in investigating the relationship between two types of fuels on the performance and exhaust emission of internal combustion engine using ceramic and metallic catalytic converters. Experimental tests were performed on Mitsubishi 4G93 engine by applying several ranges of engine speeds to determine the conversion of pollutant gases released by the engine. The obtained results specify that the usage of RON 97 equipped with metallic converters might increase the conversion percentage of 1.31% for CO and 126 ppm of HC gases. The metallic converters can perform higher conversion compared to ceramic because in the high space velocities, metallic has higher surface geometry area and higher amount of transverse Peclet number (Pi). Ceramic converters achieved conversion at 2496 ppm of NOx gas, which is higher than the metallic converter.

Main braking phase for a soft moon landing as a form of trajectory correction

NASA Astrophysics Data System (ADS)

Likhachev, V. N.; Sikharulidze, Yu. G.; Fedotov, V. P.

2013-12-01

Rationale is given for the braking profile of a spacecraft making a soft landing on the Moon's surface, including the following four phases: main braking, free fall, repeated braking, and descent at a constant speed. Due to the large altitude differential over the braking path in near-polar regions of the Moon, main braking is proposed as a type of trajectory correction impulse using no altimeter. The boundary problem solution and statistical calculations are used to give the potential energy costs and characteristics of the dispersion characteristics for this phase and choose an optimal thrust-to-weight ratio for the phase.

Aeroacoustic Study of a High-Fidelity Aircraft Model. Part 2; Unsteady Surface Pressures

NASA Technical Reports Server (NTRS)

Khorrami, Mehdi R.; Neuhart, Danny H.

2012-01-01

In this paper, we present unsteady surface pressure measurements for an 18%-scale, semi-span Gulfstream aircraft model. This high-fidelity model is being used to perform detailed studies of airframe noise associated with main landing gear, flap components, and gear-flap interaction noise, as well as to evaluate novel noise reduction concepts. The aerodynamic segment of the tests, conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel, was completed in November 2010. To discern the characteristics of the surface pressure fluctuations in the vicinity of the prominent noise sources, unsteady sensors were installed on the inboard and outboard flap edges, and on the main gear wheels, struts, and door. Various configurations were tested, including flap deflections of 0?, 20?, and 39?, with and without the main landing gear. The majority of unsteady surface pressure measurements were acquired for the nominal landing configuration where the main gear was deployed and the flap was deflected 39?. To assess the Mach number variation of the surface pressure amplitudes, measurements were obtained at Mach numbers of 0.16, 0.20, and 0.24. Comparison of the unsteady surface pressures with the main gear on and off shows significant interaction between the gear wake and the inboard flap edge, resulting in higher amplitude fluctuations when the gear is present.

A strategy for human factors/ergonomics: developing the discipline and profession.

PubMed

Dul, Jan; Bruder, Ralph; Buckle, Peter; Carayon, Pascale; Falzon, Pierre; Marras, William S; Wilson, John R; van der Doelen, Bas

2012-01-01

Human factors/ergonomics (HFE) has great potential to contribute to the design of all kinds of systems with people (work systems, product/service systems), but faces challenges in the readiness of its market and in the supply of high-quality applications. HFE has a unique combination of three fundamental characteristics: (1) it takes a systems approach (2) it is design driven and (3) it focuses on two closely related outcomes: performance and well-being. In order to contribute to future system design, HFE must demonstrate its value more successfully to the main stakeholders of system design. HFE already has a strong value proposition (mainly well-being) and interactivity with the stakeholder group of 'system actors' (employees and product/service users). However, the value proposition (mainly performance) and relationships with the stakeholder groups of 'system experts' (experts fromtechnical and social sciences involved in system design), and 'system decision makers' (managers and other decision makers involved in system design, purchase, implementation and use), who have a strong power to influence system design, need to be developed. Therefore, the first main strategic direction is to strengthen the demand for high-quality HFE by increasing awareness among powerful stakeholders of the value of high-quality HFE by communicating with stakeholders, by building partnerships and by educating stakeholders. The second main strategic direction is to strengthen the application of high-quality HFE by promoting the education of HFE specialists, by ensuring high-quality standards of HFE applications and HFE specialists, and by promoting HFE research excellence at universities and other organisations. This strategy requires cooperation between the HFE community at large, consisting of the International Ergonomics Association (IEA), local (national and regional) HFE societies, and HFE specialists. We propose a joint world-wide HFE development plan, in which the IEA takes a leadership role. Human factors/ergonomics (HFE) has much to offer by addressing major business and societal challenges regarding work and product/service systems. HFE potential, however, is underexploited. This paper presents a strategy for the HFE community to strengthen demand and application of high-quality HFE, emphasising its key elements: systems approach, design driven, and performance and well-being goals.

Glenohumeral osteoarthritis: overview, therapy, and rehabilitation.

PubMed

Macías-Hernández, Salvador Israel; Morones-Alba, Juan Daniel; Miranda-Duarte, Antonio; Coronado-Zarco, Roberto; Soria-Bastida, María de Los Angeles; Nava-Bringas, Tania; Cruz-Medina, Eva; Olascoaga-Gómez, Andrea; Tallabs-Almazan, Laura Verónica; Palencia, Chanell

2017-08-01

Glenohumeral osteoarthritis (GHOA) is a common cause of pain and functional disability of the shoulder. Despite the limited evidence, there are several options for the treatment of this pathology. The aim of this article is to provide current information on the characteristics of the disease and the pathophysiology, evidence based on medical and surgical treatments with emphasis on the rehabilitation process. It was performed with an extensive literature review, mainly clinical practice guidelines, randomized controlled trials, reviews, focusing on the rehabilitation management. There are few clinical practice guidelines that address GHOA as a pathology with unique characteristics. Evidence based treatment recommendations are mostly supported by low-quality evidence and experts' opinions, with few high levels of evidence studies guiding treatment decisions. Despite the lack of good quality evidence, rehabilitation programs have proven to be efficient and reliable, and this revision provides information and recommendations in this field. Implication of Rehabilitation Glenohumeral osteoarthritis is a common cause of pain and functional disability of the shoulder There are few clinical practice guidelines that address Glenohumeral Osteoarthritis as a pathology with unique characteristics, and recommendations for rehabilitation and therapeutic exercise are poor The paper provides current information on the characteristics of the disease, its rehabilitation process, and could be of interest for rehabilitation professionals to direct their practices in this field.

The prevalence of chronic and episodic migraine in children and adolescents.

PubMed

Ozge, A; Saşmaz, T; Buğdaycı, R; Cakmak, S E; Kurt, A Ö; Kaleağası, S H; Siva, A

2013-01-01

Migraine is the most important cause of headache leading to a decrease in the quality of life in children and adolescents. The prevalence of episodic (EM) and chronic migraine (CM) increases with increasing age, which especially focused in recent years. To evaluate the prevalence and determinants of migraine in children and adolescents, we performed this school-based epidemiological study. First part of the study was performed in 2001 that included 5562 children. Second part of the study was performed in 2007 in adolescents including 1155 young. After the main reports published, we made a new analysis in the database that focused on migraine. Totally, 10.4% of the children, predominantly the girls, received the diagnosis of migraine when they grew older (1.7% CM, 8.6% EM). CM frequency increased with increasing ages (doubled at 12 years, P = 0.035). The significant risk factors for having CM were found to be age, gender, and father and sibling headache histories. Most of the clinical characteristics of migraine are far from classical knowledge in children with CM. In adolescents, 18.6% were diagnosed as migraine (1.5%CM, 17.1%EM) with a predominance of girls without age difference. When they reached puberty after 6 years, double the number of cases with CM was headache free. Most of the young changed their headache characteristics during the follow-up period independent from management strategies. Our results showed that CM is an important cause of headache in both children and adolescents with some defining headache characteristics and risk factors concentrated in different age-groups. © 2012 The Author(s) European Journal of Neurology © 2012 EFNS.