Nanovoid growth in BCC α-Fe: influences of initial void geometry

NASA Astrophysics Data System (ADS)

Xu, Shuozhi; Su, Yanqing

2016-12-01

The growth of voids has a great impact on the mechanical properties of ductile materials by altering their microstructures. Exploring the process of void growth at the nanoscale helps in understanding the dynamic fracture of metals. While some very recent studies looked into the effects of the initial geometry of an elliptic void on the plastic deformation of face-centered cubic metals, a systematic study of the initial void ellipticity and orientation angle in body-centered cubic (BCC) metals is still lacking. In this paper, large scale molecular dynamics simulations with millions of atoms are conducted, investigating the void growth process during tensile loading of metallic thin films in BCC α-Fe. Our simulations elucidate the intertwined influences on void growth of the initial ellipticity and initial orientation angle of the void. It is shown that these two geometric parameters play an important role in the stress-strain response, the nucleation and evolution of defects, as well as the void size/outline evolution in α-Fe thin films. Results suggest that, together with void size, different initial void geometries should be taken into account if a continuum model is to be applied to nanoscale damage progression.

Theoretical distribution of gutta-percha within root canals filled using cold lateral compaction based on numeric calculus.

PubMed

Min, Yi; Song, Ying; Gao, Yuan; Dummer, Paul M H

2016-08-01

This study aimed to present a new method based on numeric calculus to provide data on the theoretical volume ratio of voids when using the cold lateral compaction technique in canals with various diameters and tapers. Twenty-one simulated mathematical root canal models were created with different tapers and sizes of apical diameter, and were filled with defined sizes of standardized accessory gutta-percha cones. The areas of each master and accessory gutta-percha cone as well as the depth of their insertion into the canals were determined mathematically in Microsoft Excel. When the first accessory gutta-percha cone had been positioned, the residual area of void was measured. The areas of the residual voids were then measured repeatedly upon insertion of additional accessary cones until no more could be inserted in the canal. The volume ratio of voids was calculated through measurement of the volume of the root canal and mass of gutta-percha cones. The theoretical volume ratio of voids was influenced by the taper of canal, the size of apical preparation and the size of accessory gutta-percha cones. Greater apical preparation size and larger taper together with the use of smaller accessory cones reduced the volume ratio of voids in the apical third. The mathematical model provided a precise method to determine the theoretical volume ratio of voids in root-filled canals when using cold lateral compaction.

Volume change associated with formation and dissociation of hydrate in sediment

USGS Publications Warehouse

Ruppel, Carolyn D.; Lee, J.Y.; Santamarina, J. Carlos

2017-01-01

Gas hydrate formation and dissociation in sediments are accompanied by changes in the bulk volume of the sediment and can lead to changes in sediment properties, loss of integrity for boreholes, and possibly regional subsidence of the ground surface over areas where methane might be produced from gas hydrate in the future. Experiments on sand, silts, and clay subject to different effective stress and containing different saturations of hydrate formed from dissolved phase tetrahydrofuran are used to systematically investigate the impact of gas hydrate formation and dissociation on bulk sediment volume. Volume changes in low specific surface sediments (i.e., having a rigid sediment skeleton like sand) are much lower than those measured in high specific surface sediments (e.g., clay). Early hydrate formation is accompanied by contraction for all soils and most stress states in part because growing gas hydrate crystals buckle skeletal force chains. Dilation can occur at high hydrate saturations. Hydrate dissociation under drained, zero lateral strain conditions is always associated with some contraction, regardless of soil type, effective stress level, or hydrate saturation. Changes in void ratio during formation-dissociation decrease at high effective stress levels. The volumetric strain during dissociation under zero lateral strain scales with hydrate saturation and sediment compressibility. The volumetric strain during dissociation under high shear is a function of the initial volume average void ratio and the stress-dependent critical state void ratio of the sediment. Other contributions to volume reduction upon hydrate dissociation are related to segregated hydrate in lenses and nodules. For natural gas hydrates, some conditions (e.g., gas production driven by depressurization) might contribute to additional volume reduction by increasing the effective stress.

Prevalence and characteristics of voiding difficulties in women: are subjective symptoms substantiated by objective urodynamic data?

PubMed

Groutz, A; Gordon, D; Lessing, J B; Wolman, I; Jaffa, A; David, M P

1999-08-01

To examine the prevalence and characteristics of voiding difficulties in women. Two hundred six consecutive female patients who attended a urogynecology clinic were recruited. Patients were interviewed regarding the presence and severity of symptoms that would suggest voiding difficulties (ie, hesitancy, straining to void, weak or prolonged stream, intermittent stream, double voiding, incomplete emptying, reduction, and positional changes to start or complete voiding). Urodynamic evidence of voiding difficulty was considered as a peak flow rate less than 12 mL/s (voided volume greater than 100 mL), or residual urine volume greater than 150 mL, on two or more readings. Residual urinary volume, flow patterns, and pressure-flow parameters were analyzed and compared between symptomatic and asymptomatic patients who had urodynamic parameters of voiding difficulties. One hundred twenty-seven (61.7%) women reported having voiding difficulty symptoms; 79 others (38.3%) were free of such symptoms. Urodynamic diagnosis of voiding difficulty was made in 40 women (19.4% of the study population): 27 in the symptomatic group and 13 in the asymptomatic group (21.2% and 16.5%, respectively). Only 1 patient had voiding difficulty due to bladder outlet obstruction. All other cases of low flow rate were due to impaired detrusor contractility. Objective evidence of voiding difficulty may be found in both symptomatic and asymptomatic patients and is usually due to impaired detrusor contractility. The clinical significance of the abnormal flow parameters in asymptomatic patients is unclear.

Improving adsorption cryocoolers by multi-stage compression and reducing void volume

NASA Technical Reports Server (NTRS)

Bard, S.

1986-01-01

It is shown that the performance of gas adsorption cryocoolers is greatly improved by using adsorbents with low void volume within and between individual adsorbent particles (reducing void volumes in plumbing lines), and by compressing the working fluid in more than one stage. Refrigerator specific power requirements and compressor volumetric efficiencies are obtained in terms of adsorbent and plumbing line void volumes and operating pressures for various charcoal adsorbents using an analytical model. Performance optimization curves for 117.5 and 80 K charcoal/nitrogen adsorption cryocoolers are given for both single stage and multistage compressor systems, and compressing the nitrogen in two stages is shown to lower the specific power requirements by 18 percent for the 117.5 K system.

Materials characterization of free volume and void properties by two-dimensional positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Hongmin; Van Horn, J. David; Jean, Y. C.; Hung, Wei-Song; Lee, Kueir-Rarn

2013-04-01

Positron annihilation lifetime spectroscopy (PALS) has been widely used to determine the free volume and void properties in polymeric materials. Recently, a two dimensional positron annihilation lifetime spectroscopy (2DPALS) system has been developed for membrane applications. The system measures the coincident signals between the lifetime and the energy which could separate the 2γ and 3γ annihilations and improve the accuracy in the determination of the free volume and void properties. When 2D-PALS is used in coupling with a variable mono-energy slow positron beam, it could be applied to a variety of material characterization. Results of free volumes and voids properties in a multi-layer polymer membrane characterized using 2D-PALS are presented.

Micromechanical investigation of ductile failure in Al 5083-H116 via 3D unit cell modeling

NASA Astrophysics Data System (ADS)

Bomarito, G. F.; Warner, D. H.

2015-01-01

Ductile failure is governed by the evolution of micro-voids within a material. The micro-voids, which commonly initiate at second phase particles within metal alloys, grow and interact with each other until failure occurs. The evolution of the micro-voids, and therefore ductile failure, depends on many parameters (e.g., stress state, temperature, strain rate, void and particle volume fraction, etc.). In this study, the stress state dependence of the ductile failure of Al 5083-H116 is investigated by means of 3-D Finite Element (FE) periodic cell models. The cell models require only two pieces of information as inputs: (1) the initial particle volume fraction of the alloy and (2) the constitutive behavior of the matrix material. Based on this information, cell models are subjected to a given stress state, defined by the stress triaxiality and the Lode parameter. For each stress state, the cells are loaded in many loading orientations until failure. Material failure is assumed to occur in the weakest orientation, and so the orientation in which failure occurs first is considered as the critical orientation. The result is a description of material failure that is derived from basic principles and requires no fitting parameters. Subsequently, the results of the simulations are used to construct a homogenized material model, which is used in a component-scale FE model. The component-scale FE model is compared to experiments and is shown to over predict ductility. By excluding smaller nucleation events and load path non-proportionality, it is concluded that accuracy could be gained by including more information about the true microstructure in the model; emphasizing that its incorporation into micromechanical models is critical to developing quantitatively accurate physics-based ductile failure models.

Extended asymmetric hot region formation due to shockwave interactions following void collapse in shocked high explosive

DOE PAGES

Shan, Tzu -Ray; Wixom, Ryan R.; Thompson, Aidan P.

2016-08-01

In both continuum hydrodynamics simulations and also multimillion atom reactive molecular dynamics simulations of shockwave propagation in single crystal pentaerythritol tetranitrate (PETN) containing a cylindrical void, we observed the formation of an initial radially symmetric hot spot. By extending the simulation time to the nanosecond scale, however, we observed the transformation of the small symmetric hot spot into a longitudinally asymmetric hot region extending over a much larger volume. Performing reactive molecular dynamics shock simulations using the reactive force field (ReaxFF) as implemented in the LAMMPS molecular dynamics package, we showed that the longitudinally asymmetric hot region was formed bymore » coalescence of the primary radially symmetric hot spot with a secondary triangular hot zone. We showed that the triangular hot zone coincided with a double-shocked region where the primary planar shockwave was overtaken by a secondary cylindrical shockwave. The secondary cylindrical shockwave originated in void collapse after the primary planar shockwave had passed over the void. A similar phenomenon was observed in continuum hydrodynamics shock simulations using the CTH hydrodynamics package. Furthermore, the formation and growth of extended asymmetric hot regions on nanosecond timescales has important implications for shock initiation thresholds in energetic materials.« less

Extended asymmetric hot region formation due to shockwave interactions following void collapse in shocked high explosive

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

Shan, Tzu -Ray; Wixom, Ryan R.; Thompson, Aidan P.

In both continuum hydrodynamics simulations and also multimillion atom reactive molecular dynamics simulations of shockwave propagation in single crystal pentaerythritol tetranitrate (PETN) containing a cylindrical void, we observed the formation of an initial radially symmetric hot spot. By extending the simulation time to the nanosecond scale, however, we observed the transformation of the small symmetric hot spot into a longitudinally asymmetric hot region extending over a much larger volume. Performing reactive molecular dynamics shock simulations using the reactive force field (ReaxFF) as implemented in the LAMMPS molecular dynamics package, we showed that the longitudinally asymmetric hot region was formed bymore » coalescence of the primary radially symmetric hot spot with a secondary triangular hot zone. We showed that the triangular hot zone coincided with a double-shocked region where the primary planar shockwave was overtaken by a secondary cylindrical shockwave. The secondary cylindrical shockwave originated in void collapse after the primary planar shockwave had passed over the void. A similar phenomenon was observed in continuum hydrodynamics shock simulations using the CTH hydrodynamics package. Furthermore, the formation and growth of extended asymmetric hot regions on nanosecond timescales has important implications for shock initiation thresholds in energetic materials.« less

Influence of oval and circular post placement using different resin cements on push-out bond strength and void volume analysed by micro-CT.

PubMed

Uzun, I; Keleş, A; Arslan, H; Güler, B; Keskin, C; Gündüz, K

2016-12-01

To evaluate the percentage volume of voids within cement layers, to determine the push-out bond strength of circular and oval fibre posts luted with different commercial resin cements in oval cross-sectional root canals, and to correlate push-out bond strength values and volume of voids of circular and oval fibre posts. Seventy-two mandibular premolars with oval-shaped root canals were selected. The specimens were divided into two main groups according to the post type (oval and circular). Groups were further divided into three subgroups (n = 24) according to resin cement type: Maxcem Elite, Rely-X Unicem and Duo-Link. The volumes of voids within the cements were analysed by micro-computed tomography (micro-CT). The bond strength was then measured using a push-out test with an Instron universal testing machine. The failure modes were evaluated. Statistical analyses were performed using a three-way anova, Tukey's post hoc, Pearson's correlation and chi-square test (P = 0.05). The push-out bond strength values were significantly affected by root canal region, post type and cement type (P < 0.001). Root canal region, post type and cement type also significantly affected void volume (P < 0.001). There was a significant interaction between post type and cement type (P < 0.001). The most frequent failure type was adhesive failure in all the groups. There was no significant correlation between the push-out bond strength and void volume (P > 0.05). Void volume did not affect push-out bond strength of oval and circular posts luted in oval canals. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Development of an Inline Urine Monitoring System for the International Space Station

NASA Technical Reports Server (NTRS)

Broyan, James Lee, Jr.; Cibuzar, Banelle R.

2008-01-01

Human exposure to microgravity during spaceflight causes bone loss. Calcium and other metabolic byproducts are excreted in urine voids. Frequent and accurate measurement of urine void volume and constituents is essential to determining crew bone loss and the effectiveness of countermeasures. Previous US Space Shuttle (SS) Urine Monitoring System (UMS) technology was unable to accurately measure urine void volumes due to cross contamination between users and fluid system instabilities. Currently, urine voids must be collected manually in a flexible plastic bag containing a known tracer quantity. The crew member must completely mix the bag then withdraw a representative syringe sample for later ground analysis. The current bag system accuracy is highly dependent on mixing technique. The International Space Station (ISS) UMS has been developed as an automated device that collects urine from the Waste and Hygiene Compartment (WHC) urinal funnel interface, separates the urine, measures the void volume, and allows for syringe sampling. After operations, the ISS UMS delivers the urine to the WHC for normal processing then flushes its plumbing with a small water volume. The current ISS UMS design incorporates an innovative rotary separator that minimizes foaming, greatly reduces cross contamination between urine voids (< 0.5 ml urine), and provides accurate volume measurements (< +/- 2% error for 100 to 1000 ml void volumes). The system performance has been validated with extensive ground tests and reduced gravity aircraft flights. The lockersized ISS UMS is currently being modified to interface with the ISS Node 3 WHC Russian ACY hardware. The operation principles, characteristics, and results are outlined in the paper.

Results of endovesical hyaluronic acid/chondroitin sulfate in the treatment of Interstitial Cystitis/Painful Bladder Syndrome.

PubMed

Porru, D; Cervigni, M; Nasta, L; Natale, F; Lo Voi, R; Tinelli, C; Gardella, B; Anghileri, A; Spinillo, A; Rovereto, B

2008-05-01

The aim of our study was to test the effect of a more viscous compound than existent hyaluronic acid formulation in helping to restore a defective glycosaminoglycan layer, and therefore in improving Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS) symptoms when administered intravesically in IC/PBS patients. A total of 23 female patients completed the study. Patients received endovesical administration of hyaluronic acid and chondroitin sulfate in normal saline, 40 ml, weekly for 12 weeks and then bi-weekly for 6 months, if there was initial response. After 12 weeks treatment both Interstitial Cystitis Symptom and Problem Index (ICSI/ICPI), pelvic pain and Urgency/Frequency Symptom Scale (PUF) showed a mean significant improvement, which was maintained thereafter. The average number of voidings and mean voiding volumes revealed significant improvement after the 12 weeks' treatment period, with a significant reduction and increase, respectively. Mean voiding volume increased from 143 ml to 191, which apparently was not reflected in a corresponding reduction of number of daily voids (from 15,5 to 14). VAS values decreased from 5,4 to 3,6 (pain) and from 6,0 to 3,5 (urgency) after the treatment cycle, showing a significant improvement. In our preliminary experience, the administration of intravesical hyaluronic acid plus chondroitine sulphate appears to be a safe and efficacious method of treatment in IC/PBS.

Morphology of the supercluster-void network in ΛCDM cosmology

NASA Astrophysics Data System (ADS)

Shandarin, Sergei F.; Sheth, Jatush V.; Sahni, Varun

2004-09-01

We report here the first systematic study of the supercluster-void network in the ΛCDM concordance cosmology in which voids and superclusters are treated on an equal footing. We study the dark matter density field in real space smoothed on a scale of 5 h-1 Mpc. Superclusters are defined as individual members of an overdense excursion set, and voids are defined as individual members of a complementary underdense excursion set at the same density threshold. We determine the geometric, topological and morphological properties of the cosmic web at a large set of density levels by computing Minkowski functionals for every supercluster and void using SURFGEN (described recently by Sheth et al.). The properties of the largest (percolating) supercluster and the complementary void are found to be very different from those of the individual superclusters and voids. In total, the individual superclusters occupy no more than about 5 per cent of the volume and contain no more than 20 per cent of the mass if the largest supercluster is excluded. Likewise, in total, individual voids occupy no more than 14 per cent of the volume and contain no more than 4 per cent of the mass if the largest void is excluded. Although superclusters are more massive and voids are more voluminous, the difference in maximum volumes is no greater than an order of magnitude. The genus value of individual superclusters can be ~5, while the genus of individual voids can reach ~50, implying a significant amount of substructure in superclusters and especially in voids. One of our main results is that large voids, as defined through the dark matter density field in real space, are distinctly non-spherical.

A clinical investigation of the mechanism of loxoprofen, a non-steroidal anti-inflammatory drug, for patients with nocturia.

PubMed

Araki, Tohru; Yokoyama, Teruhiko; Araki, Motoo; Furuya, Seiji

2008-12-01

We previously reported the effectiveness of loxoprofen sodium (loxoprofen), a non-steroidal anti-inflammatory drug, for patients with lower urinary tract symptoms (LUTS) complaining of nocturia. In this study, we explored the mechanism of loxoprofen in the treatment of nocturia. Fifty-six patients complaining of nocturia were enrolled. They took a single 60-mg tablet of loxoprofen at bedtime for 14 days. The effects of this treatment were assessed by bladder diaries. Nocturia improved (nocturia decreased >or=1 void/night) in 40 patients (71.4%). Nocturnal urine volume was reduced in 31 of 40 (77.5%) without nocturnal single-void volume increase. Nocturnal single-void volume increased in 4 of 40 (10.0%) without nocturnal urine volume reduction. Two of 40 (5.0%) demonstrated both nocturnal urine volume reduction and nocturnal single-void volume increase. Three (7.5%) were exceptions to the above. In conclusion, the main mechanism of loxoprofen is the reduction of nocturnal urine volume for the treatment of nocturia and the second mechanism is the increased bladder capacity.

The effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in cadaveric spines with simulated metastases.

PubMed

Li, Ka; Yan, Jun; Yang, Qiang; Li, Zhenfeng; Li, Jianmin

2015-01-28

For osteoporosis or spinal metastases, percutaneous vertebroplasty is effective in pain relief and improvement of mobility. However, the complication rate (cement extravasation and fat embolisms) is relatively higher in the treatment of spinal metastases. The presence of tumor tissue plays a significant role in intravertebral pressure and cement distribution and thereby affects the occurrence of complications. We investigated the effect of void creation prior to vertebroplasty on intravertebral pressure and cement distribution in spinal metastases. Eighteen vertebrae (T8-L4) from five cadaveric spines were randomly allocated for two groups (group with and without void) of nine vertebrae each. Defect was created by removing a central core of cancellous bone in the vertebral body and then filling it with 30% or 100% fresh muscle paste by volume to simulate void creation or no void creation, respectively. Then, 20% bone cement by volume of the vertebral body was injected into each specimen through a unipedicular approach at a rate of 3 mL/min. The gender of the donor, vertebral body size, bone density, cement volume, and intravertebral pressure were recorded. Then, computed tomography scans and cross sections were taken to evaluate the cement distribution in vertebral bodies. No significant difference was found between the two groups in terms of the gender of the donor, vertebral body size, bone density, or bone cement volume. The average maximum intravertebral pressure in the group with void creation was significantly lower than that in the group without void creation (1.20 versus 5.09 kPa, P = 0.001). Especially during the filling of void, the difference was more pronounced. Void creation prior to vertebroplasty allowed the bone cement to infiltrate into the lytic defect. In vertebroplasty for spinal metastases, void creation produced lower intravertebral pressure and facilitated cement filling. To reduce the occurrence of complication, it may be an alternative to eliminate the tumor tissue to create a void prior to cement injection.

Protein content of human apatite and brushite kidney stones: significant correlation with morphologic measures.

PubMed

Pramanik, Rocky; Asplin, John R; Jackson, Molly E; Williams, James C

2008-10-01

Apatite and brushite kidney stones share calcium and phosphate as their main inorganic components. We tested the hypothesis that these stone types differ in the amount of proteins present in the stones. Intact stones were intensively analyzed by microcomputed tomography (micro CT) for both morphology (including the volume of voids, i.e., space devoid of X-ray dense material) and mineral type. To extract all proteins present in kidney stones in soluble form we developed a three-step extraction procedure using the ground stone powder. Apatite stones had significantly higher levels of total protein content and void volume compared to brushite stones. The void volume was highly correlated with the total protein contents in all stones (r2 = 0.61, P < 0.0001), and brushite stones contained significantly fewer void regions and proteins than did apatite stones (3.2 +/- 4.5% voids for brushite vs. 10.8 +/- 11.2% for apatite, P < 0.005; 4.1 +/- 1.6% protein for brushite vs. 6.0 +/- 2.4% for apatite, P < 0.03). Morphological observations other than void volume did not correlate with protein content of stones, and neither did the presence or absence of minor mineral components. Our results show that protein content of brushite and apatite stones is higher than that was previously thought, and also suggest that micro CT-visible void regions are related to the presence of protein.

Phenylethynyl Containing Polyarylene Ethers/Polyimides Resin Infiltration of Composites

NASA Technical Reports Server (NTRS)

Dunn, DeRome O.

1998-01-01

The following tasks were performed at NCA&TSU during the second year in performance of the grant. LaRC-LV-1 13 resin was synthesized at NCA&TSU. In order to perform the synthesis, glassware and needed apparatus were purchased with grant funds along with the appropriate monomers. It was found that the LaRC-LV-1 13 resin was easily synthesized by the NMP solvent/toluene imminization/distilled water precipitation process. However, in use this resin exhibited a bubbling/foaming behavior during cure that was detrimental leading to the production of composite panels having a high void content. Composite panels were fabricated using compression molding and resin transfer molding (RTM) techniques. Initial fiber volume determinations were computed at NCA&TSU along with NASA-Langley measured c-scans on the panels produced. The initial results indicated a unsatisfactory level of approximately 20% by volume of voids. Testing of uniaxial coupons in compression to failure also agreed with these results. The uniaxial coupons delaminated as the major mode of failure indicative of an unacceptably low level of resin and to much void content in the final composites produced. In discussions with Dr. Brian Jensen, it was suggested the void fraction needs to be reduced to at least 2% by volume for a useful composite. The panels produced used both resin synthesized at NASA-Langley and NCA&TSU. In reviewing our progress over the past year, it was noted that the resin as formulated by the current synthesis process bubbled at elevated temperature. This was especially observed in neat resin slugs cured at the recommended one, four and eight hour cure temperatures. Pressurized cures where then performed with pressures up to 200 psi and simultaneously the lowest eight hour cure temperatures. Although this procedure reduced the amount of bubbles to some extent in the neat resin slugs it did not completely eliminate them. The cure reaction appears to be very energetic even at the lowest recommended cure temperature. Currently, the pressurized cure apparatus developed at NCA&TSU is limited to 200 psi.

Comparison of sensation-related voiding patterns between continent and incontinent women: a study with a 3-day sensation-related bladder diary (SR-BD).

PubMed

Naoemova, Irina; De Wachter, Stefan; Wyndaele, Jean-Jacques

2008-01-01

To describe and compare voiding patterns on a 3-day sensation-related bladder diary (SR-BD) in women with urinary incontinence (UI) and healthy volunteers. A total of 251 women (224 incontinent patients and 27 healthy volunteers) who recorded a 3-day SR-BD and underwent standard cystometry participated in the study. Parameters from the 3-day SR-BD were compared between incontinent patients and healthy volunteers. Compared to continent women, all groups of incontinent women noted a significantly higher 24 hr voiding frequency, a greater voiding frequency per liter diuresis, a smaller mean voided volume for different degrees of bladder sensation with more voids made with higher intensity of desire to void. The smallest mean voided volumes for different degrees of desire to void and the highest voiding frequency per liter diuresis were observed in the urge incontinence group. There were different sensation-related voiding patterns on the 3-day SR-BD from incontinent women and healthy volunteers. All incontinence groups had increased bladder sensation compared to healthy volunteers. The most severe increase of bladder sensation was observed in the patients with urgency incontinence. (c) 2007 Wiley-Liss, Inc.

Age, gender, and voided volume dependency of peak urinary flow rate and uroflowmetry nomogram in the Indian population

PubMed Central

Kumar, Vikash; Dhabalia, Jayesh V.; Nelivigi, Girish G.; Punia, Mahendra S.; Suryavanshi, Manav

2009-01-01

Objectives: The objective of this study was measurement of urine flow parameters by a non invasive urodynamic test. Variation of flow rates based on voided volume, age, and gender are described. Different nomograms are available for different populations and racial differences of urethral physiology are described. Currently, there has been no study from the Indian population on uroflow parameters. So the purpose of this study was to establish normal reference ranges of maximum and average flow rates, to see the influence of age, gender, and voided volume on flow rates, and to chart these values in the form of a nomogram. Methods: We evaluated 1,011 uroflowmetry tests in different age groups in a healthy population (healthy relatives of our patients) 16-50 year old males, >50 year old males, 5-15 year old children, and >15 year pre-menopausal and post-menopausal females. The uroflowmetry was done using the gravitimetric method. Flow chart parameters were analyzed and statistical calculations were used for drawing uroflow nomograms. Results: Qmax values in adult males were significantly higher than in the elderly and Qmax values in young females were significantly higher than in young males. Qmax values in males increased with age until 15 years old; followed by a slow decline until reaching 50 years old followed by a rapid decline after 50 years old even after correcting voided volume. Qmax values in females increased with age until they reached age 15 followed by decline in flow rate until a pre-menopausal age followed by no significant decline in post-menopausal females. Qmax values increased with voided volume until 700 cc followed by a plateau and decline. Conclusions: Qmax values more significantly correlated with age and voided volume than Qavg. Nomograms were drawn in centile form to provide normal reference ranges. Qmax values in our population were lower than described in literature. Patients with voided volume up to 50 ml could be evaluated with a nomogram. PMID:19955668

Morphological statistics of the cosmic web

NASA Astrophysics Data System (ADS)

Shandarin, Sergei F.

2004-07-01

We report the first systematic study of the supercluster-void network in the ΛCDM concordance cosmology treating voids and superclusters on an equal footing. We study the dark matter density field in real space smoothed with the Ls = 5 h[minus sign]1Mpc Gaussian window. Superclusters and voids are defined as individual members of over-dense and under-dense excursion sets respectively. We determine the morphological properties of the cosmic web at a large number of dark matter density levels by computing Minkowski functionals for every supercluster and void. At the adopted smoothing scale individual superclusters totally occupy no more than about 5% of the total volume and contain no more than 20% of mass if the largest supercluster is excluded. Likewise, individual voids totally occupy no more than 14% of volume and contain no more than 4% of mass if the largest void is excluded. The genus of individual superclusters can be ˜ 5 while the genus of individual voids reaches ˜ 55, implying significant amount of substructure in superclusters and especially in voids. Large voids are typically distinctly non-spherical.

Theoretical study for volume changes associated with the helix-coil transition of peptides.

PubMed

Imai, T; Harano, Y; Kovalenko, A; Hirata, F

2001-12-01

We calculate the partial molar volumes and their changes associated with the coil(extended)-to-helix transition of two types of peptide, glycine-oligomer and glutamic acid-oligomer, in aqueous solutions by using the Kirkwood-Buff solution theory coupled with the three-dimensional reference interaction site model (3D-RISM) theory. The volume changes associated with the transition are small and positive. The volume is analyzed by decomposing it into five contributions following the procedure proposed by Chalikian and Breslauer: the ideal volume, the van der Waals volume, the void volume, the thermal volume, and the interaction volume. The ideal volumes and the van der Waals volumes do not change appreciably upon the transition. In the both cases of glycine-peptide and glutamic acid-peptide, the changes in the void volumes are positive, while those in the thermal volumes are negative, and tend to balance those in the void volumes. The change in the interaction volume of glycine-peptide does not significantly contribute, while that of glutamic acid-peptide makes a negative contribution. Copyright 2001 John Wiley & Sons, Inc. Biopolymers 59: 512-519, 2001

[Comparison of new portable home electronic uroflowmeter with Laborie uroflowmeter].

PubMed

Guan, Zhi-chen; Deng, Xiao-lin; Zhang, Qian

2011-08-18

To design a new portable home electronic uroflowmeter and compare it with traditional methods. The system consists of collectors, urine conducting apparatus, intelligent cell phone, wireless network communication technology, computer analysis and drawing, and data storage technology, etc., and can automatically collect voiding information from patients with lower urinary tract symptoms(LUTS) Through Bluetooth, the voiding information was sent to the patient's intelligent cell phone from the collector, then stored directly by intelligent cell phone and wirelessly transmitted to the workstation in hospital. The system was primarily tested with regard to accuracy of measurement of the voided volume. Multiple doses with known volume were introduced in the system and Laborie uroflowmeter. Furthermore, 38 outpatients who had LUTS were tested simultaneously with the system and Laborie uroflowmeter. The statistical method for assessing agreement between the two methods of clinical measurement was Bland-Altman analysis. Among the subjects, there were 22 male patients and 16 female patients, ranging from 21 to 37 years old, with an average age of 25.5 years, of whom, 19 were tested once and 19 patients twice, equaling to 57 tests. The system could accurately collect and analyze voiding time, uroflowmetry, voided volume, and automatically provide uroflowmetry parameters. The measurement error of 100, 200, 300, 500 and 800 mL is less than 5%. 12.28%, 5.26% and 3.51% of the Qmax, Qave and voided volume points were beyond the 95% limits of agreement. The maximum absolute values of the Qmax, Qave and voided volume difference were 0.38 mL/s, 0.70 mL/s and 2.90 mL, respectively.They agreed with the recommendation of Standardization International Continence Society. The new portable home electronic uroflowmeter has good agreement with Laborie uroflowmeter,and is a new LUTS monitoring system integrated with correct, reliable, real-time, convenient and easy-managing advantages. It is as noninvasive and reliable as traditional methods, and its portable feature facilitates application out of hospitals. It can also record voiding diaries.

Hot spot formation and chemical reaction initiation in shocked HMX crystals with nanovoids: a large-scale reactive molecular dynamics study.

PubMed

Zhou, Tingting; Lou, Jianfeng; Zhang, Yangeng; Song, Huajie; Huang, Fenglei

2016-07-14

We report million-atom reactive molecular dynamic simulations of shock initiation of β-cyclotetramethylene tetranitramine (β-HMX) single crystals containing nanometer-scale spherical voids. Shock induced void collapse and subsequent hot spot formation as well as chemical reaction initiation are observed which depend on the void size and impact strength. For an impact velocity of 1 km s(-1) and a void radius of 4 nm, the void collapse process includes three stages; the dominant mechanism is the convergence of upstream molecules toward the centerline and the downstream surface of the void forming flowing molecules. Hot spot formation also undergoes three stages, and the principal mechanism is kinetic energy transforming to thermal energy due to the collision of flowing molecules on the downstream surface. The high temperature of the hot spot initiates a local chemical reaction, and the breakage of the N-NO2 bond plays the key role in the initial reaction mechanism. The impact strength and void size have noticeable effects on the shock dynamical process, resulting in a variation of the predominant mechanisms leading to void collapse and hot spot formation. Larger voids or stronger shocks result in more intense hot spots and, thus, more violent chemical reactions, promoting more reaction channels and generating more reaction products in a shorter duration. The reaction products are mainly concentrated in the developed hot spot, indicating that the chemical reactivity of the hmx crystal is greatly enhanced by void collapse. The detailed information derived from this study can aid a thorough understanding of the role of void collapse in hot spot formation and the chemical reaction initiation of explosives.

Development of an In-line Urine Monitoring System for the International Space Station

NASA Technical Reports Server (NTRS)

Broyan, James Lee, Jr.; Cibuzar, Branelle R.

2009-01-01

Exposure to microgravity during space flight causes bone loss when calcium and other metabolic by-products are excreted in urine voids. Frequent and accurate measurement of urine void volume and constituents is thus essential in determining crew bone loss and the effectiveness of the countermeasures that are taken to minimize this loss. Earlier space shuttle Urine Monitoring System (UMS) technology was unable to accurately measure urine void volumes due to the cross-contamination that took place between users, as well as to fluid system instabilities. Crew urine voids are currently collected manually in a flexible plastic bag that contains a known tracer quantity. A crew member must completely mix the contents of this bag before withdrawing a representative syringe sample for later ground analysis. The existing bag system accuracy is therefore highly dependent on mixing technique. The International Space Station (ISS) UMS has been developed as an automated device that collects urine from the Waste and Hygiene Compartment (WHC) urinal funnel interface, separates the urine, measures void volume, and allows for syringe sampling. After the ISS UMS has been used by a crew member, it delivers urine to the WHC for normal processing. The UMS plumbing is then flushed with a small volume of water. The current ISS UMS design incorporates an innovative rotary separator that minimizes foaming, consequently greatly reducing cross-contamination among urine voids (less than 0.5 mL urine) while also providing accurate volume measurements (less than 2 percent error for 100 to 1,000 mL void volumes). ISS UMS performance has been validated through extensive ground tests and reduced-gravity aircraft flights. The locker-sized ISS UMS is currently undergoing a design modification that will permit it to interface with the ISS Node 3 WHC Russian toilet (ACY) hardware. The operating principles, characteristics, and results of this design modification are outlined here.

Free-Volume Nanostructurization in Ga-Modified As2Se3 Glass.

PubMed

Shpotyuk, Ya; Ingram, A; Shpotyuk, O; Dziedzic, A; Boussard-Pledel, C; Bureau, B

2016-12-01

Different stages of intrinsic nanostructurization related to evolution of free-volume voids, including phase separation, crystalline nuclei precipitation, and growth, were studied in glassy As2Se3 doped with Ga up to 5 at. %, using complementary techniques of positron annihilation lifetime spectroscopy, X-ray powder diffraction, and scanning electron microscopy with energy-dispersive X-ray analysis. Positron lifetime spectra reconstructed in terms of a two-state trapping model testified in favor of a native void structure of g-As2Se3 modified by Ga additions. Under small Ga content (below 3 at. %), the positron trapping in glassy alloys was dominated by voids associated with bond-free solid angles of bridging As2Se4/2 units. This void agglomeration trend was changed on fragmentation with further Ga doping due to crystalline Ga2Se3 nuclei precipitation and growth, these changes being activated by employing free volume from just attached As-rich glassy matrix with higher content of As2Se4/2 clusters. Respectively, the positron trapping on free-volume voids related to pyramidal AsSe3/2 units (like in parent As2Se3 glass) was in obvious preference in such glassy crystalline alloys.

Determination of need for water soaking period in measurement of concrete volume of permeable voids : technical summary.

DOT National Transportation Integrated Search

2016-10-01

Water permeability of concrete is one of the key factors concerning : many concrete deterioration problems. It is often evaluated indirectly by : measuring the volume of permeable voids through the KT-73 (2012) testing : procedures. These procedures ...

Urine Monitoring System

NASA Technical Reports Server (NTRS)

Feedback, Daniel L.; Cibuzar, Branelle R.

2009-01-01

The Urine Monitoring System (UMS) is a system designed to collect an individual crewmember's void, gently separate urine from air, accurately measure void volume, allow for void sample acquisition, and discharge remaining urine into the Waste Collector Subsystem (WCS) onboard the International Space Station. The Urine Monitoring System (UMS) is a successor design to the existing Space Shuttle system and will resolve anomalies such as: liquid carry-over, inaccurate void volume measurements, and cross contamination in void samples. The crew will perform an evaluation of airflow at the ISS UMS urinal hose interface, a calibration evaluation, and a full user interface evaluation. o The UMS can be used to facilitate non-invasive methods for monitoring crew health, evaluation of countermeasures, and implementation of a variety of biomedical research protocols on future exploration missions.

Determination of need for water soaking period in measurement of concrete volume of permeable voids : final report.

DOT National Transportation Integrated Search

2016-10-01

Water permeability of concrete is one of the key factors concerning many concrete deterioration : problems. It is often evaluated indirectly by measuring the volume of permeable voids through the KT-73 : (2012) testing procedures. These procedures in...

Multicenter, prospective, comparative cohort study evaluating the efficacy and safety of alfuzosin 10 mg with regard to blood pressure in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia with or without antihypertensive medications.

PubMed

Zhang, Li Tao; Lee, Sung Won; Park, Kwangsung; Chung, Woo Sik; Kim, Sae Woong; Hyun, Jae Seog; Moon, Doo Geon; Yang, Sang-Kuk; Ryu, Ji Kan; Yang, Dae Yul; Moon, Ki Hak; Min, Kweon Sik; Park, Jong Kwan

2015-01-01

The objective of this study was to assess the efficacy and safety of alfuzosin 10 mg monotherapy or combined antihypertensive medication on blood pressure (BP) in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH/LUTS) with or without antihypertensive medication. This was a 3-month, multicenter, randomized, open-label study in 335 patients aged ≥45 years with a clinical diagnosis of BPH/LUTS by medical history and clinical examination, a total International Prostatic Symptom Score (IPSS) ≥8 points, a maximum flow rate >5 mL/sec and ≤15 mL/sec, and a voided volume ≥120 mL. Eligible subjects were randomized to receive alfuzosin 10 mg as monotherapy (group 1) or alfuzosin 10 mg + antihypertensive combination therapy (group 2). Based on baseline BP and hypertensive history with or without antihypertensive medications at first medical examination, group 1 was divided into two subgroups of normotensive and untreated hypertensive patients, and group 2 into two subgroups of controlled hypertensive and uncontrolled hypertensive patients. The primary study outcomes were change in IPSS, BP, and heart rate from baseline. Secondary outcomes were change in IPSS-quality of life score, maximum flow rate, average flow rate, voided volume, and post-voided volume. The overall BP change was not significantly different between groups 1 and 2 (systolic BP, P=0.825; diastolic BP, P>0.999). In patients with uncontrolled or untreated hypertension, alfuzosin 10 mg alone or combined with antihypertensive therapy significantly decreased systolic and diastolic BP. The mean difference in total IPSS and IPSS-quality of life scores from baseline between groups 1 and 2 was 0.45 (95% CI: -1.26, 2.16) and 0.12 (95% CI: -0.21, 0.45), respectively (both P>0.05). Maximum flow rate, average flow rate, voided volume, and post-voided volume at endpoint were numerically, but not significantly, changed from baseline (all P>0.05). This study shows that alfuzosin 10 mg is effective and well tolerated in patients with BPH/LUTS with or without antihypertensive medications. However, in patients with uncontrolled or untreated hypertension, alfuzosin 10 mg alone or in combination with antihypertensive medication appears to decrease systolic and diastolic BP, and these patients should be warned about a decrease in BP on initiation of therapy.

Herpes zoster-associated acute urinary retention: a case report.

PubMed

Julia, Jimmy J; Cholhan, Hilary J

2007-01-01

An 87-year-old woman presents with a 4-week history of urinary incontinence during which she had been treated for disseminated herpes zoster virus (HZV). On physical exam painful vesicles involving the entire vulvar region with mainly right sacral distribution were found. A catheterized volume exceeded 600 ml of retained urine after the patient failed to void spontaneously. Multichannel voiding-pressure urodynamic studies revealed an acontractile neurogenic bladder with overflow incontinence. The patient was discharged on a conservative regimen with arrangement for visiting nurse services to perform intermittent self-catheterization twice daily. Urodynamic testing was repeated 10 weeks after initial symptoms. During voiding cystometry a biphasic increase in detrusor pressure of 15 cm H2O was observed with no increase in abdominal pressure. The patient emptied 400 ml with a postvoid residual of 300 ml. Recovery from HZV-associated bladder emptying dysfunction can be achieved usually through conservative management, including intermittent self-catheterization. Complete recovery time ranges from 4 to 10 weeks.

A 3D Printed Implantable Device for Voiding the Bladder Using Shape Memory Alloy (SMA) Actuators.

PubMed

Hassani, Faezeh Arab; Peh, Wendy Yen Xian; Gammad, Gil Gerald Lasam; Mogan, Roshini Priya; Ng, Tze Kiat; Kuo, Tricia Li Chuen; Ng, Lay Guat; Luu, Percy; Yen, Shih-Cheng; Lee, Chengkuo

2017-11-01

Underactive bladder or detrusor underactivity (DU) is defined as a reduction of contraction strength or duration of the bladder wall. Despite the serious healthcare implications of DU, there are limited solutions for affected individuals. A flexible 3D printed implantable device driven by shape memory alloys (SMA) actuators is presented here for the first time to physically contract the bladder to restore voluntary control of the bladder for individuals suffering from DU. This approach is used initially in benchtop experiments with a rubber balloon acting as a model for the rat bladder to verify its potential for voiding, and that the operating temperatures are safe for the eventual implantation of the device in a rat. The device is then implanted and tested on an anesthetized rat, and a voiding volume of more than 8% is successfully achieved for the SMA-based device without any surgical intervention or drug injection to relax the external sphincter.

Air void analyzer for plastic concrete : technical summary report.

DOT National Transportation Integrated Search

2008-11-01

The best protection against freeze-thaw cycles in concrete is to have a good air void : system. Although microscopic, concrete is a porous material. Conventional field tests, : the volumetric or pressure tests, only provide the volume of air voids in...

Voids in Gravitational Instability Scenarios - Part One - Global Density and Velocity Fields in an Einstein - De-Sitter Universe

NASA Astrophysics Data System (ADS)

van de Weygaert, R.; van Kampen, E.

1993-07-01

The first results of an extensive study of the structure and dynamics of underdense regions in gravitational instability scenarios are presented. Instead of adopting spherically symmetric voids with some idealized initial density and velocity profile, underdense regions of a given size and depth, embedded in an initial density fluctuation field, are generated. In order to accomplish this in a consistent way, these initial conditions are set up by means of Bertschinger's constrained random field code. The generated particle samples of 64^3^ particles in a box of side 100 Mpc are followed into the non-linear regime by Bertschinger's PM N- body code. In this way we address the dependence of the structure and kinematics of the void both on the initial depth of the void and on the fluctuation field in which it is embedded. In particular, this study provides some understanding of how far fluctuations on small scales modify the dynamics of the large-scale void, and especially of how far the properties of small structures inside the void are affected by the global properties of the void. One of the conspicuous features of the initial density fields inside protovoids appears to be the existence of a `void hierarchy', with small voids embedded in larger voids. The survival of this hierarchy during the riot evolution of the void depends critically on the initial depth as well as on the clustering scenario involved. As well as presenting a qualitative discussion of the structure of underdense regions in initial density fields in different scenarios, and the results of simulations of the ensuing non-linear evolution, we concentrate in particular on a comparison of the global density and velocity fields in voids with predictions from linear theory as well as from the spherical outflow model. The relation between the initial linear depth, the resulting non-linear depth and the excess expansion velocities in voids is addressed. In addition, we find that, while near its centre a void becomes more and more spherical, the shape of its boundary is influenced to a large extent by the structures surrounding the void and therefore is generally more irregular. In this first study we concentrate on single voids in Einstein-de Sitter universes. The underdense regions considered are linear 1 σ_0_, 2 σ_0_ and 3 σ_0_ dips in fields that are Gaussian-smoothed on a scale of R_G_ = 10 h^-1^ Mpc, approximately half the size of the Bootes void. These regions are studied in terms of the Cold Dark Matter and Hot Dark Matter scenarios as well as in terms of the scale-free scenarios P(k) is proportional to k^0^, k^-1^ and k^-2^. The Hubble constant is taken to be H_0_ = 100 h km s^-1^ Mpc^-1^.

Dynamic Failure of Materials. Volume 1 - Experiments and Analyses

DTIC Science & Technology

1998-11-01

initial increments of voids do not lead to substantial relaxation of stress. In this case, the condition (8.1) gives Vv = Ao- aVv * ß=— (8.10) pc...enough strain steps to define the process accurately. At each strain step, a combined Newton-Raphson and regulafalsi solution technique (multiple trials ...laser surgery. Clinical studies have demonstrated that, for some applications, surgical lasers are superior to conventional surgical procedures

Porosity of Self-Compacting Concrete (SCC) incorporating high volume fly ash

NASA Astrophysics Data System (ADS)

Kristiawan, S. A.; Sunarmasto; Murti, G. Y.

2017-02-01

Degradation of concrete could be triggered by the presence of aggressive agents from the environment into the body of concrete. The penetration of these agents is influenced by the pore characteristics of the concrete. Incorporating a pozzolanic material such as fly ash could modify the pore characteristic of the concrete. This research aims to investigate the influence of incorporating fly ash at high volume level on the porosity of Self-Compacting Concrete (SCC). Laboratory investigations were carried out following the ASTM C642 for measuring density and volume of permeable pores (voids) of the SCC with varying fly ash contents (50-70% by weight of total binder). In addition, a measurement of permeable voids by saturation method was carried out to obtain an additional volume of voids that could not be measured by the immersion and boiling method of ASTM C642. The results show that the influence of fly ash content on the porosity appears to be dependent on age of SCC. At age less than 56 d, fly ash tends to cause an increase of voids but at 90 d of age it reduces the pores. The additional pores that can be penetrated by vacuum saturation method counts about 50% of the total voids.

On the abundance of extreme voids II: a survey of void mass functions

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

Chongchitnan, Siri; Hunt, Matthew, E-mail: s.chongchitnan@hull.ac.uk, E-mail: m.d.hunt@2012.hull.ac.uk

2017-03-01

The abundance of cosmic voids can be described by an analogue of halo mass functions for galaxy clusters. In this work, we explore a number of void mass functions: from those based on excursion-set theory to new mass functions obtained by modifying halo mass functions. We show how different void mass functions vary in their predictions for the largest void expected in an observational volume, and compare those predictions to observational data. Our extreme-value formalism is shown to be a new practical tool for testing void theories against simulation and observation.

Small-angle x-ray scattering in amorphous silicon: A computational study

NASA Astrophysics Data System (ADS)

Paudel, Durga; Atta-Fynn, Raymond; Drabold, David A.; Elliott, Stephen R.; Biswas, Parthapratim

2018-05-01

We present a computational study of small-angle x-ray scattering (SAXS) in amorphous silicon (a -Si) with particular emphasis on the morphology and microstructure of voids. The relationship between the scattering intensity in SAXS and the three-dimensional structure of nanoscale inhomogeneities or voids is addressed by generating large high-quality a -Si networks with 0.1%-0.3% volume concentration of voids, as observed in experiments using SAXS and positron annihilation spectroscopy. A systematic study of the variation of the scattering intensity in the small-angle scattering region with the size, shape, number density, and the spatial distribution of the voids in the networks is presented. Our results suggest that the scattering intensity in the small-angle region is particularly sensitive to the size and the total volume fraction of the voids, but the effect of the geometry or shape of the voids is less pronounced in the intensity profiles. A comparison of the average size of the voids obtained from the simulated values of the intensity, using the Guinier approximation and Kratky plots, with that of the same from the spatial distribution of the atoms in the vicinity of void surfaces is presented.

The Clock mutant mouse is a novel experimental model for nocturia and nocturnal polyuria.

PubMed

Ihara, Tatsuya; Mitsui, Takahiko; Nakamura, Yuki; Kira, Satoru; Miyamoto, Tatsuya; Nakagomi, Hiroshi; Sawada, Norifumi; Hirayama, Yuri; Shibata, Keisuke; Shigetomi, Eiji; Shinozaki, Yoichi; Yoshiyama, Mitsuharu; Andersson, Karl-Erik; Nakao, Atsuhito; Takeda, Masayuki; Koizumi, Schuichi

2017-04-01

The pathophysiologies of nocturia (NOC) and nocturnal polyuria (NP) are multifactorial and their etiologies remain unclear in a large number of patients. Clock genes exist in most cells and organs, and the products of Clock regulate circadian rhythms as representative clock genes. Clock genes regulate lower urinary tract function, and a newly suggested concept is that abnormalities in clock genes cause lower urinary tract symptoms. In the present study, we investigated the voiding behavior of Clock mutant (Clock Δ19/Δ19 ) mice in order to determine the effects of clock genes on NOC/NP. Male C57BL/6 mice aged 8-12 weeks (WT) and male C57BL/6 Clock Δ19/Δ19 mice aged 8 weeks were used. They were bred under 12 hr light/dark conditions for 2 weeks and voiding behavior was investigated by measuring water intake volume, urine volume, urine volume/void, and voiding frequency in metabolic cages in the dark and light periods. No significant differences were observed in behavior patterns between Clock Δ19/Δ19 and WT mice. Clock Δ19/Δ19 mice showed greater voiding frequencies and urine volumes during the sleep phase than WT mice. The diurnal change in urine volume/void between the dark and light periods in WT mice was absent in Clock Δ19/Δ19 mice. Additionally, functional bladder capacity was significantly lower in Clock Δ19/Δ19 mice than in WT mice. We demonstrated that Clock Δ19/Δ19 mice showed the phenotype of NOC/NP. The Clock Δ19/Δ19 mouse may be used as an animal model of NOC and NP. Neurourol. Urodynam. 36:1034-1038, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Detrusor expulsive strength is preserved, but responsiveness to bladder filling and urinary sensitivity is diminished in the aging mouse

PubMed Central

DeAngelis, Anthony; Kuchel, George A.

2012-01-01

The prevalence of urinary symptoms increases with age and is a significant source of distress, morbidity, and expense in the elderly. Recent evidence suggests that symptoms in the aged may result from sensory dysfunction, rather than abnormalities of detrusor performance. Therefore, we employed a pressure/flow multichannel urethane-anesthetized mouse cystometry model to test the hypothesis that in vivo detrusor performance does not degrade with aging. Secondarily, we sought to evaluate sensory responsiveness to volume using pressure-volume data generated during bladder filling. Cystometric data from 2-, 12-, 22-, and 26-mo-old female C57BL6 mice were compared. All 2- and 12-mo-old mice, 66% of 22-mo-old mice, and 50% of 26-mo-old mice responded to continuous bladder filling with periodic reflex voiding. Abdominal wall contraction with voiding had a minimal contribution to expulsive pressure, whereas compliance pressure was a significant contributor. Maximum bladder pressure, estimated detrusor pressure, detrusor impulse (pressure-time integral), as well as indices of detrusor power and work, did not decrease with aging. Bladder precontraction pressures decreased, compliance increased, and nonvoiding contraction counts did not change with increasing age. Intervoid intervals, per-void volumes, and voiding flow rates increased with age. Calculations approximating wall stress during filling suggested loss of bladder volume sensitivity with increasing age. We conclude that aging is associated with an impaired ability to respond to the challenge of continuous bladder filling with cyclic voiding, yet among responsive animals, voiding detrusor contraction strength does not degrade with aging in this murine model. Furthermore, indirect measures suggest that bladder volume sensitivity is diminished. Thus, changes in homeostatic reserve and peripheral and/or central sensory mechanisms may be important contributors to aging-associated changes in bladder function. PMID:22204955

Towards the damage evaluation using Gurson-Tvergaard-Needleman (GTN) model for hot forming processes

NASA Astrophysics Data System (ADS)

Imran, Muhammad; Bambach, Markus

2018-05-01

In the production of semi-finished metal products, hot forming is used to eliminate the pores and voids from the casting process under compressive stresses and to modify the microstructure for further processing. In the case of caliber and flat rolling processes, tensile stresses occur at certain roll gap ratios which promote pore formation on nonmetallic inclusion. The formation of new pores contributes to ductile damage and reduces the load carrying capacity of the material. In the literature, the damage nucleation and growth during the hot forming process are not comprehensively described. The aim of this study is to understand the damage initiation and growth mechanism during hot forming processes. Hot tensile tests are performed at different temperatures and strain rates for 16MnCrS5 steel. To investigate the influence of geometrical variations on the damage mechanism, specimens with different stress triaxiality ratios are used. Finite element simulations using the Gurson-Tvergaard-Needleman (GTN) damage model are performed to estimate the critical void fraction for the damage initiation and the evolution of the void volume fraction. The results showed that the GTN model underestimates the softening of the material due to the independence of the temperature and the strain rate.

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

Ritter, Boyd

Insensitive high explosives (IHEs) based on 1,3,5-triamino 2,4,6-trinitro-benzene (TATB) are the IHEs of choice for use in nuclear warheads over conventional high explosives when safety is the only consideration, because they are very insensitive to thermal or mechanical initiation stimuli. It is this inherent insensitivity to high temperatures, shock, and impact, which provides detonation design challenges when designing TATB explosive systems while at the same time providing a significant level of protection against accidental initiation. Although classified as IHE, over the past few years the focus on explosive safety has demonstrated that the shock sensitivity of TATB is influenced withmore » respect to temperature. A number of studies have been performed on TATB and TATB formulations, plastic bonded explosives (PBX) 9502, and LX-17-01 (LX-17), which demonstrates the increase in shock sensitivity of the explosive after it has been preheated or thermally cycled over various temperature ranges. Many studies suggest the change in sensitivity is partly due to the decomposition rates of the temperature elevated TATB. Others point to the coefficient of thermal expansion, the crystalline structures of TATB and/or the combination of all factors, which create voids which can become active hot spots. During thermal cycling, TATB is known to undergo an irreversible increase in specific volume called ratchet growth. This increase in specific volume correlates to a decrease in density. This decrease in density and increase in volume, demonstrate the creations of additional void spaces which could serve as potential new initiation hot spots thus, increasing the overall sensitivity of the HE. This literature review evaluates the published works to understand why the shock sensitivity of TATB-based plastic bonded explosives (PBXs) changes with temperature.« less

Collapse of elongated voids in porous energetic materials: Effects of void orientation and aspect ratio on initiation

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

2017-04-01

The sensitivity of porous energetic materials depends on mesostructural heterogeneities such as voids, defects, cracks, and grain boundaries. The mesostructure of pressed explosives contains voids of arbitrary shapes including elongated voids of various orientations and aspect ratios. Mesoscale simulations to date have analyzed the effect of void morphology on the sensitivity of energetic materials for idealized shapes such as cylindrical, conical, and elliptical. This work analyzes the sensitivity behavior of elongated voids in an HMX matrix subject to shock loading. Simulations show that sensitivity of elongated voids depends strongly on orientation as well as aspect ratio. Ranges of orientations and aspects ratios are identified that enhance or inhibit initiation. Insights obtained from single elongated void analyses are used to identify sensitive locations in an imaged mesostructure of a pressed explosive sample.

Void statistics, scaling, and the origins of large-scale structure

NASA Technical Reports Server (NTRS)

Fry, J. N.; Giovanelli, Riccardo; Haynes, Martha P.; Melott, Adrian L.; Scherrer, Robert J.

1989-01-01

The probability that a volume of the universe of given size and shape spaced at random will be void of galaxies is used here to study various models of the origin of cosmological structures. Numerical simulations are conducted on hot-particle and cold-particle-modulated inflationary models with and without biasing, on isothermal or initially Poisson models, and on models where structure is seeded by loops of cosmic string. For the Pisces-Perseus redshift compilation of Giovanelli and Haynes (1985), it is found that hierarchical scaling is obeyed for subsamples constructed with different limiting magnitudes and subsamples taken at random. This result confirms that the hierarchical ansatz holds valid to high order and supports the idea that structure in the observed universe evolves by a regular process from an almost Gaussian primordial state. Neutrino models without biasing show the effect of a strong feature in the initial power spectrum. Cosmic string models do not agree well with the galaxy data.

Reserving Interior Void Space for Volume Change Accommodation: An Example of Cable-Like MWNTs@SnO2@C Composite for Superior Lithium and Sodium Storage.

PubMed

Zhao, Yi; Wei, Chao; Sun, Shengnan; Wang, Luyuan Paul; Xu, Zhichuan J

2015-06-01

Reserving interior void space in the cable-like structure of multiwalled carbon nanotubes-in-SnO 2 -in-carbon layer (MWNTs@SnO 2 @C) is reported for the first time. Such a design enables the structure performing excellent for Li and Na storage, which benefit from the good electrical conductivity of MWNTs and carbon layer as well as the reserved void space to accommodate the volume changes of SnO 2 .

Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

Treesearch

Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

2016-01-01

After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

Deformation of periodic nanovoid structures in Mg single crystals

NASA Astrophysics Data System (ADS)

Xu, Shuozhi; Su, Yanqing; Zare Chavoshi, Saeed

2018-01-01

Large scale molecular dynamics (MD) simulations in Mg single crystal containing periodic cylindrical voids subject to uniaxial tension along the z direction are carried out. Models with different initial void sizes and crystallographic orientations are explored using two interatomic potentials. It is found that (i) a larger initial void always leads to a lower yield stress, in agreement with an analytic prediction; (ii) in the model with x[\\bar{1}100]-y[0001]-z[11\\bar{2}0] orientations, the two potentials predict different types of tension twins and phase transformation; (iii) in the model with x[0001]-y[11\\bar{2}0]-z[\\bar{1}100] orientations, the two potentials identically predict the nucleation of edge dislocations on the prismatic plane, which then glide away from the void, resulting in extrusions at the void surface; in the case of the smallest initial void, these surface extrusions pinch the void into two voids. Besides bringing new physical understanding of the nanovoid structures, our work highlights the variability and uncertainty in MD simulations arising from the interatomic potential, an issue relatively lightly addressed in the literature to date.

ONLY THE LONELY: H I IMAGING OF VOID GALAXIES

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

Kreckel, K.; Van Gorkom, J. H.; Platen, E.

2011-01-15

Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an environment undisturbed by the complex processes modifying galaxies in clusters and groups, as well as provide an observational test for theories of cosmological structure formation. We have completed a pilot survey for the H I imaging aspects of a new Void Galaxy Survey (VGS), imaging 15 void galaxies in H I in local (d < 100 Mpc) voids. H I masses range from 3.5 x 10{sup 8} to 3.8 x 10{sup 9} M{sub sun}, withmore » one nondetection with an upper limit of 2.1 x 10{sup 8} M{sub sun}. Our galaxies were selected using a structural and geometric technique to produce a sample that is purely environmentally selected and uniformly represents the void galaxy population. In addition, we use a powerful new backend of the Westerbork Synthesis Radio Telescope that allows us to probe a large volume around each targeted galaxy, simultaneously providing an environmentally constrained sample of fore- and background control samples of galaxies while still resolving individual galaxy kinematics and detecting faint companions in H I. This small sample makes up a surprisingly interesting collection of perturbed and interacting galaxies, all with small stellar disks. Four galaxies have significantly perturbed H I disks, five have previously unidentified companions at distances ranging from 50 to 200 kpc, two are in interacting systems, and one was found to have a polar H I disk. Our initial findings suggest void galaxies are a gas-rich, dynamic population which present evidence of ongoing gas accretion, major and minor interactions, and filamentary alignment despite the surrounding underdense environment.« less

COMPARISON OF FLOWRATES AND VOIDED VOLUMES DURING NON-INSTRUMENTED UROFLOWMETRY AND PRESSURE-FLOW STUDIES IN WOMEN WITH STRESS INCONTINENCE

PubMed Central

Mueller, ER; Litman, H; Rickey, LR; Sirls, L; Norton, P; Wilson, T; Moalli, P; Albo, M; Zimmern, P

2014-01-01

Aims The Blaivas-Groutz nomogram defines voiding obstruction in women using Qmax from the NIF and the maximum detrusor pressure (Pdetmax) from the PFS. The aim of this study was to understand the relationship between NIF and PFS maximum flow rates in women with stress incontinence. Methods We analyzed the UDS of 597 women with stress-dominant urinary incontinence. Each subject underwent a NIF and then a PFS. Mixed model was used to test the hypothesis that the relationship between flow rates and voided volume were similar for NIF and PFS. Results There were 452 subjects with both NIF and PFS studies that met the inclusion criteria and had max flow rate (Qmax) for both NIF and PFS. The mean age was 53. Overall, higher voided volumes were observed during PFS compared to NIF and subjects had higher Qmax with NIF compared to PFS. The relationship between Qmax and VV was significantly different between NIF and PFS (p < 0.004). At 200 mL, NIF Qmax was 14% higher than PFS Qmax and this difference increased to 30% at 700mL. Conclusion The difference between PFS Qmax and NIF Qmax increases as voided volumes increase. As a result, values from PFS and NIF cannot be used interchangeably as has been suggested in the Blaivas-Groutz nomogram for obstruction in women. PMID:24797058

Sandwich-like C@SnO2/Sn/void@C hollow spheres as improved anode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Wang, Huijun; Jiang, Xinya; Chai, Yaqin; Yang, Xia; Yuan, Ruo

2018-03-01

As lithium ion batteries (LIBs) anode, SnO2 suffers fast capacity fading due to its large volume expansion during discharge/charge process. To overcome the problem, sandwich-like C@SnO2/Sn/void@C hollow spheres (referred as C@SnO2/Sn/void@C HSs) are prepared by in-situ polymerization and carbonization, using hollow SnO2 as self-template and dopamine as carbon source. The C@SnO2/Sn/void@C HSs possesses the merits of hollow and core/void/shell structure, so that they can accommodate the volume change under discharge/charge process, shorten the transmission distance of Li ions, own more contact area for the electrolyte. Thanks to these advantages, C@SnO2/Sn/void@C HSs display excellent electrochemical performance as anode materials for LIBs, which deliver a high capacity of 786.7 mAh g-1 at the current density of 0.5 A g-1 after 60 cycles. The simple synthesis method for C@SnO2/Sn/void@C HSs with special structure will provide a promising method for preparing other anode materials for LIBs.

Union operation image processing of data cubes separately processed by different objective filters and its application to void analysis in an all-solid-state lithium-ion battery.

PubMed

Yamamoto, Yuta; Iriyama, Yasutoshi; Muto, Shunsuke

2016-04-01

In this article, we propose a smart image-analysis method suitable for extracting target features with hierarchical dimension from original data. The method was applied to three-dimensional volume data of an all-solid lithium-ion battery obtained by the automated sequential sample milling and imaging process using a focused ion beam/scanning electron microscope to investigate the spatial configuration of voids inside the battery. To automatically fully extract the shape and location of the voids, three types of filters were consecutively applied: a median blur filter to extract relatively larger voids, a morphological opening operation filter for small dot-shaped voids and a morphological closing operation filter for small voids with concave contrasts. Three data cubes separately processed by the above-mentioned filters were integrated by a union operation to the final unified volume data, which confirmed the correct extraction of the voids over the entire dimension contained in the original data. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Ceramic impregnated superabrasives

DOEpatents

Radtke, Robert P.; Sherman, Andrew

2009-02-10

A superabrasive fracture resistant compact is formed by depositing successive layers of ceramic throughout the network of open pores in a thermally stable self-bonded polycrystalline diamond or cubic boron nitride preform. The void volume in the preform is from approximately 2 to 10 percent of the volume of the preform, and the average pore size is below approximately 3000 nanometers. The preform is evacuated and infiltrated under at least about 1500 pounds per square inch pressure with a liquid pre-ceramic polymerizable precursor. The precursor is infiltrated into the preform at or below the boiling point of the precursor. The precursor is polymerized into a solid phase material. The excess is removed from the outside of the preform, and the polymer is pyrolized to form a ceramic. The process is repeated at least once more so as to achieve upwards of 90 percent filling of the original void volume. When the remaining void volume drops below about 1 percent the physical properties of the compact, such as fracture resistance, improve substantially. Multiple infiltration cycles result in the deposition of sufficient ceramic to reduce the void volume to below 0.5 percent. The fracture resistance of the compacts in which the pores are lined with formed in situ ceramic is generally at least one and one-half times that of the starting preforms.

Comparison between uroflowmetry and sonouroflowmetry in recording of urinary flow in healthy men.

PubMed

Krhut, Jan; Gärtner, Marcel; Sýkora, Radek; Hurtík, Petr; Burda, Michal; Luňáček, Libor; Zvarová, Katarína; Zvara, Peter

2015-08-01

To evaluate the accuracy of sonouroflowmetry in recording urinary flow parameters and voided volume. A total of 25 healthy male volunteers (age 18-63 years) were included in the study. All participants were asked to carry out uroflowmetry synchronous with recording of the sound generated by the urine stream hitting the water level in the urine collection receptacle, using a dedicated cell phone. From 188 recordings, 34 were excluded, because of voided volume <150 mL or technical problems during recording. Sonouroflowmetry recording was visualized in a form of a trace, representing sound intensity over time. Subsequently, the matching datasets of uroflowmetry and sonouroflowmetry were compared with respect to flow time, voided volume, maximum flow rate and average flow rate. Pearson's correlation coefficient was used to compare parameters recorded by uroflowmetry with those calculated based on sonouroflowmetry recordings. The flow pattern recorded by sonouroflowmetry showed a good correlation with the uroflowmetry trace. A strong correlation (Pearson's correlation coefficient 0.87) was documented between uroflowmetry-recorded flow time and duration of the sound signal recorded with sonouroflowmetry. A moderate correlation was observed in voided volume (Pearson's correlation coefficient 0.68) and average flow rate (Pearson's correlation coefficient 0.57). A weak correlation (Pearson's correlation coefficient 0.38) between maximum flow rate recorded using uroflowmetry and sonouroflowmetry-recorded peak sound intensity was documented. The present study shows that the basic concept utilizing sound analysis for estimation of urinary flow parameters and voided volume is valid. However, further development of this technology and standardization of recording algorithm are required. © 2015 The Japanese Urological Association.

Dental artifacts in the head and neck region: implications for Dixon-based attenuation correction in PET/MR.

PubMed

Ladefoged, Claes N; Hansen, Adam E; Keller, Sune H; Fischer, Barbara M; Rasmussen, Jacob H; Law, Ian; Kjær, Andreas; Højgaard, Liselotte; Lauze, Francois; Beyer, Thomas; Andersen, Flemming L

2015-12-01

In the absence of CT or traditional transmission sources in combined clinical positron emission tomography/magnetic resonance (PET/MR) systems, MR images are used for MR-based attenuation correction (MR-AC). The susceptibility effects due to metal implants challenge MR-AC in the neck region of patients with dental implants. The purpose of this study was to assess the frequency and magnitude of subsequent PET image distortions following MR-AC. A total of 148 PET/MR patients with clear visual signal voids on the attenuation map in the dental region were included in this study. Patients were injected with [(18)F]-FDG, [(11)C]-PiB, [(18)F]-FET, or [(64)Cu]-DOTATATE. The PET/MR data were acquired over a single-bed position of 25.8 cm covering the head and neck. MR-AC was based on either standard MR-ACDIXON or MR-ACINPAINTED where the susceptibility-induced signal voids were substituted with soft tissue information. Our inpainting algorithm delineates the outer contour of signal voids breaching the anatomical volume using the non-attenuation-corrected PET image and classifies the inner air regions based on an aligned template of likely dental artifact areas. The reconstructed PET images were evaluated visually and quantitatively using regions of interests in reference regions. The volume of the artifacts and the computed relative differences in mean and max standardized uptake value (SUV) between the two PET images are reported. The MR-based volume of the susceptibility-induced signal voids on the MR-AC attenuation maps was between 1.6 and 520.8 mL. The corresponding/resulting bias of the reconstructed tracer distribution was localized mainly in the area of the signal void. The mean and maximum SUVs averaged across all patients increased after inpainting by 52% (± 11%) and 28% (± 11%), respectively, in the corrected region. SUV underestimation decreased with the distance to the signal void and correlated with the volume of the susceptibility artifact on the MR-AC attenuation map. Metallic dental work may cause severe MR signal voids. The resulting PET/MR artifacts may exceed the actual volume of the dental fillings. The subsequent bias in PET is severe in regions in and near the signal voids and may affect the conspicuity of lesions in the mandibular region.

Unnoticed Post-Void Residual Urine Volume in People with Moderate to Severe Intellectual Disabilities: Prevalence and Risk Factors

ERIC Educational Resources Information Center

de Waal, K. H.; Tinselboer, B. M.; Evenhuis, H. M.; Penning, C.

2009-01-01

Background: Increased post-void residual urine volume (PVR) is often seen in geriatric populations. People with intellectual disabilities (ID) have risk factors in common with these populations. Aims: To investigate in adults with ID: (1) Feasibility of portable ultrasound bladder scanning; (2) Prevalence of PVR; and (3) Relations with proposed…

Analysis of nocturia with 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration: concept for effective treatment modality.

PubMed

Udo, Yukihiro; Nakao, Masahiro; Honjo, Hisashi; Ukimura, Osamu; Kawauchi, Akihiro; Kitakoji, Hiroshi; Miki, Tsuneharu

2011-03-01

• To determine the relationship between the number of nocturia and 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration as well as to assess the significance of these factors with respect to eliminating nocturnal voidings in individual patients with nocturia. • Among 532 participants who completed a 3-day bladder diary between April 2005 and December 2006, the diaries of 450 participants without 24-h polyuria were analyzed. • Clinical variables such as the number of daytime and night-time voids, 24-h urine volume, nocturnal polyuria index, daytime and night-time maximum voided volumes (MVV), night/day MVV ratio, sleep duration and proportion of night/day urine production rates were obtained from each diary. • Participants were classified into eight groups according to values of three factors: nocturnal MVV, proportion of night/day urine production rates and length of sleep duration. • Each group was divided into three subgroups: non-nocturics (number of nocturnal voidings is zero), mild nocturics (number of nocturnal voidings is one) and severe nocturics (number of nocturnal voidings is two or more). • The data from non-nocturics with three normal factors were regarded as the normal control and compared with the variables of the other subgroups using Dunnett's method. • Variables that form the basis of classifying participants into eight groups and corresponding to abnormal factors of each group were statistically significant in all the subgroups of each group. • Furthermore, a significantly increased 24-h urine volume was found in severe nocturics of the group with three normal factors. • A significantly decreased 24-h urine volume was found in non-nocturics of groups with nocturnal polyuria, decreased bladder capacity and both long sleep duration and nocturnal polyuria. • A significantly increased nocturnal MVV and night/day MVV ratio were shown in non-nocturics and mild nocturics of the groups with nocturnal polyuria and both long sleep duration and nocturnal polyuria. • Because nocturia is a multifactorial disorder and closely related to four factors (i.e. 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration), the evaluation of all these factors appears to be clinically useful for determining the main contributing factor in patients with nocturia as well as the suitable treatment modality on an individual basis. • Physicians should take all these factors into consideration in the evaluation and treatment of nocturia. © 2010 THE AUTHORS. JOURNAL COMPILATION © 2010 BJU INTERNATIONAL.

Toughening mechanism in elastometer-modified epoxy resins: Part 1

NASA Technical Reports Server (NTRS)

Yee, A. F.; Pearson, R. A.

1983-01-01

Several plaques of Epon 828, cured with piperidine, modified with hycar(r) CTBN 1300X8, Hycar(R) CTBN 1300X13, and Hycar(R) CTBN 1300x15, and in some cases modified with biphenol A (BPA), yielded properly toughened epoxies with rubber particle diameters ranging from 0.1 to 10 microns. Fracture toughness experiments indicate that toughness was more a function of rubber content than the rubber particle size. Tensile volumetric behavior of the near resin exhibits two regions: an initial region where the increase in volume strain was due to the Poisson's effect, and a second region where a slower rate of increase in volume strain was due to shear deformation. Tensile volumetric deformation of an elastomer-modified epoxy exhibits the same type of behavior to that of the neat resin at low rates ( 3.2x0.01 sec(-1)). But at very high strain rates, which correspond more closely to the strain rates at the crack tip, there exists an increase in volume strain beyond the Poisson's effect. TEM, SEM and OM studies indicate that the rubber particles had voided. When a thin section from the deformed region is viewed under crossed-polarized light, shear bands are seen connecting voided rubber particles. From this information cavitation and enhanced shear band formation is proposed as the toughening mechanism.

MicroCT analysis of a retrieved root restored with a bonded fiber-reinforced composite dowel: a pilot study.

PubMed

Lorenzoni, Fabio Cesar; Bonfante, Estevam A; Bonfante, Gerson; Martins, Leandro M; Witek, Lukasz; Silva, Nelson R F A

2013-08-01

This evaluation aimed to (1) validate micro-computed tomography (microCT) findings using scanning electron microscopy (SEM) imaging, and (2) quantify the volume of voids and the bonded surface area resulting from fiber-reinforced composite (FRC) dowel cementation technique using microCT scanning technology/3D reconstructing software. A fiberglass dowel was cemented in a condemned maxillary lateral incisor prior to its extraction. A microCT scan was performed of the extracted tooth creating a large volume of data in DICOM format. This set of images was imported to image-processing software to inspect the internal architecture of structures. The outer surface and the spatial relationship of dentin, FRC dowel, cement layer, and voids were reconstructed. Three-dimensional spatial architecture of structures and volumetric analysis revealed that 9.89% of the resin cement was composed of voids and that the bonded area between root dentin and cement was 60.63% larger than that between cement and FRC dowel. SEM imaging demonstrated the presence of voids similarly observed using microCT technology (aim 1). MicroCT technology was able to nondestructively measure the volume of voids within the cement layer and the bonded surface area at the root/cement/FRC interfaces (aim 2). The interfaces at the root dentin/cement/dowel represent a timely and relevant topic where several efforts have been conducted in the past few years to understand their inherent features. MicroCT technology combined with 3D reconstruction allows for not only inspecting the internal arrangement rendered by fiberglass adhesively bonded to root dentin, but also estimating the volume of voids and contacted bond area between the dentin and cement layer. © 2013 by the American College of Prosthodontists.

Comparison of water and air charged transducer catheter pressures in the evaluation of cystometrogram and voiding pressure studies.

PubMed

McKinney, Timothy B; Babin, Elizabeth A; Ciolfi, Veronica; McKinney, Cynthia R; Shah, Nima

2018-04-01

Air-charged (AC) and water-perfused (WP) catheters have been evaluated for differences in measuring pressures for voiding dysfunction. Typically, a two-catheter system was used. We believe that simultaneous pressure measurements with AC and WP in a single catheter will provide analogous pressures for coughs, Valsalvas, and maximum pressures in voiding pressure studies (VPS). This IRB approved prospective study included 50 women over age 21. AC dual TDOC catheters were utilized. The water-filling channel served as the bladder filler and the water pressure readings. Patients were evaluated with empty bladders and at volumes of 50-100 mL, 200 mL, and maximum capacity with cough and Valsalva maneuvers. Comparative analysis was performed on maximum stress peak pressures. At maximum bladder capacity, VPS was done and maximum voiding pressure was recorded. Comparing coughs and Valsalva maneuvers pressures, there was significant increase in variability between AC and WP measurements with less than 50 mL volume (P < 0.001). Significant correlations were observed between AC and WP measurements for coughs and Valsalvas with bladder volume over 50 mL. Visual impression showed virtually identical tracings. Cough measurements had an average difference of 0.25 cmH 2 O (±8.81) and Valsalva measurements had an average difference of 3.15 cmH 2 O (±4.72). Thirty-eight women had usable maximum voiding pressure measurements and had a strong correlation. Cystometrogram and maximum voiding pressure measurements done with either water or air charged catheters will yield similarly accurate results and are comparable. Results suggest more variability at low bladder volumes <50 mL. © 2018 Wiley Periodicals, Inc.

High-resolution simulations of cylindrical void collapse in energetic materials: Effect of primary and secondary collapse on initiation thresholds

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

2017-04-01

Void collapse in energetic materials leads to hot spot formation and enhanced sensitivity. Much recent work has been directed towards simulation of collapse-generated reactive hot spots. The resolution of voids in calculations to date has varied as have the resulting predictions of hot spot intensity. Here we determine the required resolution for reliable cylindrical void collapse calculations leading to initiation of chemical reactions. High-resolution simulations of collapse provide new insights into the mechanism of hot spot generation. It is found that initiation can occur in two different modes depending on the loading intensity: Either the initiation occurs due to jet impact at the first collapse instant or it can occur at secondary lobes at the periphery of the collapsed void. A key observation is that secondary lobe collapse leads to large local temperatures that initiate reactions. This is due to a combination of a strong blast wave from the site of primary void collapse and strong colliding jets and vortical flows generated during the collapse of the secondary lobes. The secondary lobe collapse results in a significant lowering of the predicted threshold for ignition of the energetic material. The results suggest that mesoscale simulations of void fields may suffer from significant uncertainty in threshold predictions because unresolved calculations cannot capture the secondary lobe collapse phenomenon. The implications of this uncertainty for mesoscale simulations are discussed in this paper.

Serotonin (5-HT)2A/2C receptor agonist (2,5-dimethoxy-4-idophenyl)-2-aminopropane hydrochloride (DOI) improves voiding efficiency in the diabetic rat.

PubMed

Tu, Hongjian; Cao, Nailong; Gu, Baojun; Si, Jiemin; Chen, Zhong; Andersson, Karl-Erik

2015-07-01

To examine the effects of the serotonin (5-HT)2A/2C receptor agonist (2,5-dimethoxy-4-idophenyl)-2-aminopropane hydrochloride (DOI) on micturition in rats with diabetes mellitus (DM). Female Sprague-Dawley rats (n = 16) were divided into two groups: rats with Type 1 DM and age-matched control rats. DM was induced by i.p. injection of streptozotocin (65 mg/kg) and detailed cystometrogram (CMG) studies were performed 8 weeks post-injection in all rats under urethane anaesthesia. The selective 5-HT2A antagonist ketanserin was administered after each DOI dose-response curve was plotted. All drugs were administered i.v. Compared with controls, comprehensive urodynamic studies showed that DM rats had a higher bladder capacity and post-void residual urine volume (PVR), and a markedly lower voiding efficiency. In DM rats, DOI (0.01-0.3 mg/kg) induced significant dose-dependent increases in micturition volume and reductions in PVR, resulting in greater voiding efficiency. CMG measurements showed a dose-dependent increase in high-frequency oscillation (HFO) activity, evidenced by an increased duration of HFOs per voiding. This correlated with the improved voiding efficiency. Ketanserin (0.1 mg/kg) partially or completely reversed the DOI-induced changes. The HFOs observed in the present study seem to correlate with external urethral sphincter bursting activity during voiding. Bladder voiding efficiency was reduced in DM rats. The 5-HT2A receptor agonist can enhance HFO activity and improves voiding efficiency, and so may represent a new strategy to improve voiding efficiency after DM in experimental studies. © 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd.

Laboratory measurements of electrical resistivity versus water content on small soil cores

NASA Astrophysics Data System (ADS)

Robain, H.; Camerlynck, C.; Bellier, G.; Tabbagh, A.

2003-04-01

The assessment of soil water content variations more and more leans on geophysical methods that are non invasive and that allow a high spatial sampling. Among the different methods, DC electrical imaging is moving forward. DC Electrical resistivity shows indeed strong seasonal variations that principally depend on soil water content variations. Nevertheless, the widely used Archie's empirical law [1], that links resistivity with voids saturation and water conductivity is not well suited to soil materials with high clay content. Furthermore, the shrinking and swelling properties of soil materials have to be considered. Hence, it is relevant to develop new laboratory experiments in order to establish a relation between electrical resistivity and water content taking into account the rheological and granulometrical specificities of soil materials. The experimental device developed in IRD laboratory allows to monitor simultaneously (i) the water content, (ii) the electrical resistivity and (iii) the volume of a small cylindrical soil core (100cm3) put in a temperature controlled incubator (30°C). It provides both the shrinkage curve of the soil core (voids volume versus water content) and the electrical resistivity versus water content curve The modelisation of the shrinkage curve gives for each moisture state the water respectively contained in macro and micro voids [2], and then allows to propose a generalized Archie's like law as following : 1/Rs = 1/Fma.Rma + 1/Fmi.Rmi and Fi = Ai/(Vi^Mi.Si^Ni) with Rs : the soil resistivity. Fma and Fmi : the so called "formation factor" for macro and micro voids, respectively. Rma and Rmi : the resistivity of the water contained in macro and micro voids, respectively. Vi : the volume of macro and micro voids, respectively. Si : the saturation of macro and micro voids, respectively. Ai, Mi and Ni : adjustment coefficients. The variations of Rmi are calculated, assuming that Rma is a constant. Indeed, the rise of ionic concentration in water may be neglected during the sewage of macro voids as it corresponds to a small quantity of water for the studied samples. Soil solid components are generally electrical insulators, the conduction of electrical current only lies on two phenomenon occurring in water : (i) volume conduction controlled by the electrolyte concentration in water and the geometrical characteristics of macro voids network ; (ii) surface conduction controlled by the double diffuse layer that depends on the solid-liquid interactions, the specific surface of clay minerals and the geometry of particles contacts. For the water contained in macro voids the preeminent phenomenon seems to be volume conduction while for the water contained in micro voids, it seems to be surface conduction. This hypothesis satisfyingly explains the shape of the electrical resistivity versus water content curves obtained for three different oxisols with clayey, clayey-sandy and sandy-clayey texture. [1] Archie G.E. 1942. The electrical resistivity log as an aid in determining some reservoirs characteristics. Trans. AIME, 146, 54-67. [2] Braudeau E. et al. 1999. New device and method for soil shrinkage curve measurement and characterization. S.S.S.A.J., 63(3), 525-535.

Phase-field study on geometry-dependent migration behavior of voids under temperature gradient in UO2 crystal matrix

NASA Astrophysics Data System (ADS)

Chen, Weijin; Peng, Yuyi; Li, Xu'an; Chen, Kelang; Ma, Jun; Wei, Lingfeng; Wang, Biao; Zheng, Yue

2017-10-01

In this work, a phase-field model is established to capture the void migration behavior under a temperature gradient within a crystal matrix, with an appropriate consideration of the surface diffusion mechanism and the vapor transport mechanism. The interfacial energy and the coupling between the vacancy concentration field and the crystal order parameter field are carefully modeled. Simulations are performed on UO2. The result shows that for small voids (with an area ≤ πμm2), the well-known characteristics of void migration, in consistence with the analytical model, can be recovered. The migration is manifested by a constant velocity and a minor change of the void shape. In contrast, for large voids (with an area of ˜10 μm2) initially in circular shapes, significant deformation of the void from a circular to cashew-like shape is observed. After long-time migration, the deformed void would split into smaller voids. The size-dependent behavior of void migration is due to the combined effect of the interfacial energy (which tends to keep the void in circular shape) and the surface diffusion flow (which tends to deform the void due to the nonuniform diffusion along the surface). Moreover, the initial shape of the void modifies the migration velocity and the time point when splitting occurs (for large voids) at the beginning of migration due to the shape relaxation of the void. However, it has a minor effect on the long-time migration. Our work reveals novel void migration behaviors in conditions where the surface-diffusion mechanism is dominant over the vapor transport mechanism; meanwhile, the size of the void lies at a mediate size range.

On the observability of coupled dark energy with cosmic voids

NASA Astrophysics Data System (ADS)

Sutter, P. M.; Carlesi, Edoardo; Wandelt, Benjamin D.; Knebe, Alexander

2015-01-01

Taking N-body simulations with volumes and particle densities tuned to match the sloan digital sky survey DR7 spectroscopic main sample, we assess the ability of current void catalogues to distinguish a model of coupled dark matter-dark energy from Λ cold dark matter cosmology using properties of cosmic voids. Identifying voids with the VIDE toolkit, we find no statistically significant differences in the ellipticities, but find that coupling produces a population of significantly larger voids, possibly explaining the recent result of Tavasoli et al. In addition, we use the universal density profile of Hamaus et al. to quantify the relationship between coupling and density profile shape, finding that the coupling produces broader, shallower, undercompensated profiles for large voids by thinning the walls between adjacent medium-scale voids. We find that these differences are potentially measurable with existing void catalogues once effects from survey geometries and peculiar velocities are taken into account.

Comparison of nocturia response to desmopressin treatment in elderly men with and without nocturnal polyuria in real-life practice.

PubMed

Chen, S-L; Huang, Y-H; Hung, T-W; Ou, Y-C

2016-05-01

To evaluate the safety and efficacy of low-dose desmopressin in elderly men with and without nocturnal polyuria (NP) in real-life practice. Patients with lower urinary tract symptoms (LUTS)/ benign prostate hyperplasia (BPH) who were≧ 65 years old with refractory nocturia were enrolled in this study. We retrospectively analysed elderly men treated with adding desmopressin to current medications for nocturia according to category of the baseline nocturnal urine volume. The 48-h frequency volume chart (FVC), International Prostate Symptom Score (IPSS) and quality of life (QoL) were initially assessed and re-evaluated 12 weeks later. Serum sodium level was checked 1 week, 4 weeks, and 12 weeks after initiation of desmopressin therapy or suspected hyponatremia event. The mean change in numbers of nocturnal voids was evaluated for efficacy of treatment. A total of 136 patients were included with 55 in non-NP group and 81 in NP group. Hypertension was more common in NP group in regard of comorbidities. During treatment period, there were significant reductions of nocturnal voids from 4.22 ± 1.38 to 2.31 ± 0.98 (p < 0.001) in non-NP group and from 4.52 ± 1.23 to 2.07 ± 0.89 (p < 0.001) in NP group. The reduction in nocturnal voids was more significant in NP group (2.44 ± 1.15 vs. 1.91 ± 1.48, p = 0.003). The mean decrease in serum sodium levels were 3.89 ± 1.22 mmol/l (p < 0.001) in non-NP group and 4.69 ± 3.5 mmol/l (p < 0.001) in NP group at the extreme value. Long-term treatment with low-dose desmopressin is safe and effective for nocturia with or without NP in elderly patients with LUTS/BPH during real-life practice. Patients should be well informed about the disease and are closely followed. © 2016 John Wiley & Sons Ltd.

Multi-Shell Hollow Nanogels with Responsive Shell Permeability

PubMed Central

Schmid, Andreas J.; Dubbert, Janine; Rudov, Andrey A.; Pedersen, Jan Skov; Lindner, Peter; Karg, Matthias; Potemkin, Igor I.; Richtering, Walter

2016-01-01

We report on hollow shell-shell nanogels with two polymer shells that have different volume phase transition temperatures. By means of small angle neutron scattering (SANS) employing contrast variation and molecular dynamics (MD) simulations we show that hollow shell-shell nanocontainers are ideal systems for controlled drug delivery: The temperature responsive swelling of the inner shell controls the uptake and release, while the thermoresponsive swelling of the outer shell controls the size of the void and the colloidal stability. At temperatures between 32 °C < T < 42 °C, the hollow nanocontainers provide a significant void, which is even larger than the initial core size of the template, and they possess a high colloidal stability due to the steric stabilization of the swollen outer shell. Computer simulations showed, that temperature induced switching of the permeability of the inner shell allows for the encapsulation in and release of molecules from the cavity. PMID:26984478

Radiographic and Histologic Evaluation of a Bone Void that Formed After Recombinant Human Bone Morphogenetic Protein-2-Mediated Sinus Graft Augmentation: A Case Report.

PubMed

Kang, Hyun-Joo; Jun, Choong-Man; Yun, Jeong-Ho

2016-01-01

In the present case report, the authors describe radiographic and histologic observations of a bone void that formed after a sinus augmentation using a graft material that contained recombinant human bone morphogenetic protein-2 (rhBMP-2) and discuss clinical and histologic implications of their findings. Sinus augmentation was performed using a graft material comprising 1 g of hydroxyapatite/β-tricalcium phosphate, which contained 1 mg of rhBMP-2. Radiographic evaluation was conducted with panoramic radiographs and computed tomography images of the augmented maxillary sinus, which were analyzed using a three-dimensional image-reconstruction program. Histologic evaluation was also performed on a biopsy specimen obtained 6 months after the sinus augmentation. The total augmented volume increased from 1,582.2 mm(3) immediately after the sinus augmentation to 3,344.9 mm3 at 6 months after the augmentation because of the formation of a bone void. Twenty-six months after the sinus augmentation, the bone void remained but had reduced in volume, with the total augmented volume reduced to 2,551.7 mm(3). Histologically, new bone was observed to be in contact with the grafted particles, and a fatty marrow-like tissue was present in the area of the bone void. This case report shows that the bone void that had formed after sinus augmentation resolved over time and seemed to be partially replaced with new bone. Furthermore, none of the implants failed, and clinical adverse events were not observed during the follow-up period.

Thermal inertia mapping of below ground objects and voids

NASA Astrophysics Data System (ADS)

Del Grande, Nancy K.; Ascough, Brian M.; Rumpf, Richard L.

2013-05-01

Thermal inertia (effusivity) contrast marks the borders of naturally heated below ground object and void sites. The Dual Infrared Effusivity Computed Tomography (DIRECT) method, patent pending, detects and locates the presence of enhanced heat flows from below ground object and void sites at a given area. DIRECT maps view contrasting surface temperature differences between sites with normal soil and sites with soil disturbed by subsurface, hollow or semi-empty object voids (or air gaps) at varying depths. DIRECT utilizes an empirical database created to optimize the scheduling of daily airborne thermal surveys to view and characterize unseen object and void types, depths and volumes in "blind" areas.

The Kirkendall and Frenkel effects during 2D diffusion process

NASA Astrophysics Data System (ADS)

Wierzba, Bartek

2014-11-01

The two-dimensional approach for inter-diffusion and voids generation is presented. The voids evolution and growth is discussed. This approach is based on the bi-velocity (Darken) method which combines the Darken and Brenner concepts that the volume velocity is essential in defining the local material velocity in multi-component mixture at non-equilibrium. The model is formulated for arbitrary multi-component two-dimensional systems. It is shown that the voids growth is due to the drift velocity and vacancy migration. The radius of the void can be easily estimated. The distributions of (1) components, (2) vacancy and (3) voids radius over the distance is presented.

Mechanical Properties versus Morphology of Ordered Polymers. Volume III. Part I

DTIC Science & Technology

1982-08-01

measured by wide angle x-ray scattering and differential scanning calorimetry, is unrelated to the diffuse scattered intensity [62]. Cellulose acetate which...increasing void fraction, in air swollen cellulose . Comparison of the volume fraction of voids calculated from the SAXS integrated intensity with...1964). 63. P.H. Hermans, D. Heikens, and A. Weidinger, "A Quantitative Investigation on the X-Ray Small Angle Scattering of Cellulose Fibers. Part II

Effect of craniosacral therapy on lower urinary tract signs and symptoms in multiple sclerosis.

PubMed

Raviv, Gil; Shefi, Shai; Nizani, Dalia; Achiron, Anat

2009-05-01

To examine whether craniosacral therapy improves lower urinary tract symptoms of multiple sclerosis (MS) patients. A prospective cohort study. Out-patient clinic of multiple sclerosis center in a referral medical center. Hands on craniosacral therapy (CST). Change in lower urinary tract symptoms, post voiding residual volume and quality of life. Patients from our multiple sclerosis clinic were assessed before and after craniosacral therapy. Evaluation included neurological examination, disability status determination, ultrasonographic post voiding residual volume estimation and questionnaires regarding lower urinary tract symptoms and quality of life. Twenty eight patients met eligibility criteria and were included in this study. Comparison of post voiding residual volume, lower urinary tract symptoms and quality of life before and after craniosacral therapy revealed a significant improvement (0.001>p>0.0001). CST was found to be an effective means for treating lower urinary tract symptoms and improving quality of life in MS patients.

Anatomic and functional properties of bulboglandularis striated muscle support its contribution as sphincter in female rabbit micturition.

PubMed

Corona-Quintanilla, Dora Luz; López-Juárez, Rhode; Zempoalteca, René; Cuevas, Estela; Castelán, Francisco; Martínez-Gómez, Margarita

2016-08-01

To determine anatomic and functional properties of the bulboglandularis muscle (Bgm) for clarifying its role in micturition in female rabbits. Virgin female rabbits were used to describe the gross anatomy and innervation of the Bgm, to determine the effect of the Bgm contraction on urethral pressure, and to evaluate the Bgm activity during the induced-micturition. Both electromyogram and cystometrogram activity were simultaneously recorded in urethane-anesthetized rabbits. Bladder function was assessed measuring standard urodynamic variables before and after blocking the Bgm activity for approaching its contribution to micturition. The relevance of the Bgm activation for micturition was approached applying lidocaine injections. The Bgm was composed of circularly oriented striated fibers enveloping distal urethra and pelvic vagina. Both the venous plexus and urethra were comprised by the Bgm contraction induced by electrical stimulation. The Bgm showed bursts of tonic activity at the storage phase of micturition that gradually decreased until turning off as the onset of the voiding phase. The voided volume, the voiding efficiency, the threshold pressure, and the maximal pressure were decreased after lidocaine injection. Contrastingly, the threshold volume, the residual volume, the voiding duration, and the urethral resistance at voiding were increased. Present anatomical and physiological findings support that the Bgm acts as a sphincter during micturition of female rabbits. Neurourol. Urodynam. 35:689-695, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Influence of the internal anatomy on the leakage of root canals filled with thermoplastic technique.

PubMed

Al-Jadaa, Anas; Attin, T; Peltomäki, T; Heumann, C; Schmidlin, P R; Paquè, F

2018-04-01

The aim of this paper is to evaluate the influence of the internal anatomy on the leakage of root canals filled with the thermoplastic technique. The upper central incisors (UCI) and mesial roots of the lower molars (MRLM) (n = 12 each) were tested regarding leakage using the gas-enhanced permeation test (GEPT) after root filling. The quality of the root fillings was assessed using micro-computed tomography (μCT) by superimposing scans before and after treatment to calculate unfilled volume. The calculated void volume was compared between the groups and correlated to the measured leakage values. Data were analyzed using t test and Pearson's correlation tests (p < 0.05). The mean void volume did not differ between UCI and MRLM (13.7 ± 6.2% vs. 14.2 ± 6.8%, respectively). However, significantly more leakage was evident in the MRLM (p < 0.001). While the leakage correlated highly to the void volume in the MRLM group (R 2  = 0.981, p < 0.001), no correlation was found in UCI (R 2  = 0.467, p = 0.126). MRLM showed higher leakage values, which correlated to the void volume in the root canal fillings. Care should always be taken while doing root canal treatments, but attention to teeth with known/expected complex root canal anatomy should be considered.

Modeling void growth and movement with phase change in thermal energy storage canisters

NASA Technical Reports Server (NTRS)

Darling, Douglas; Namkoong, David; Skarda, J. R. L.

1993-01-01

A scheme was developed to model the thermal hydrodynamic behavior of thermal energy storage salts. The model included buoyancy, surface tension, viscosity, phases change with density difference, and void growth and movement. The energy, momentum, and continuity equations were solved using a finite volume formulation. The momentum equation was divided into two pieces. The void growth and void movement are modeled between the two pieces of the momentum equations. Results showed this scheme was able to predict the behavior of thermal energy storage salts.

Development of Electrical Capacitance Sensors for Accident Tolerant Fuel (ATF) Testing at the Transient Reactor Test (TREAT) Facility

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

Liu, Maolong; Ryals, Matthew; Ali, Amir

2016-08-01

A variety of instruments are being developed and qualified to support the Accident Tolerant Fuels (ATF) program and future transient irradiations at the Transient Reactor Test (TREAT) facility at Idaho National Laboratory (INL). The University of New Mexico (UNM) is working with INL to develop capacitance-based void sensors for determining the timing of critical boiling phenomena in static capsule fuel testing and the volume-averaged void fraction in flow-boiling in-pile water loop fuel testing. The static capsule sensor developed at INL is a plate-type configuration, while UNM is utilizing a ring-type capacitance sensor. Each sensor design has been theoretically and experimentallymore » investigated at INL and UNM. Experiments are being performed at INL in an autoclave to investigate the performance of these sensors under representative Pressurized Water Reactor (PWR) conditions in a static capsule. Experiments have been performed at UNM using air-water two-phase flow to determine the sensitivity and time response of the capacitance sensor under a flow boiling configuration. Initial measurements from the capacitance sensor have demonstrated the validity of the concept to enable real-time measurement of void fraction. The next steps include designing the cabling interface with the flow loop at UNM for Reactivity Initiated Accident (RIA) ATF testing at TREAT and further characterization of the measurement response for each sensor under varying conditions by experiments and modeling.« less

Three-Dimensional Analysis of Voids in AM60B Magnesium Tensile Bars Using Computed Tomography Imagery

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

Waters, A M

2001-05-01

In an effort to increase automobile fuel efficiency as well as decrease the output of harmful greenhouse gases, the automotive industry has recently shown increased interest in cast light metals such as magnesium alloys in an effort to increase weight savings. Currently several magnesium alloys such as AZ91 and AM60B are being used in structural applications for automobiles. However, these magnesium alloys are not as well characterized as other commonly used structural metals such as aluminum. This dissertation presents a methodology to nondestructively quantify damage accumulation due to void behavior in three dimensions in die-cast magnesium AM60B tensile bars asmore » a function of mechanical load. Computed tomography data was acquired after tensile bars were loaded up to and including failure, and analyzed to characterize void behavior as it relates to damage accumulation. Signal and image processing techniques were used along with a cluster labeling routine to nondestructively quantify damage parameters in three dimensions. Void analyses were performed including void volume distribution characterization, nearest neighbor distance calculations, shape parameters, and volumetric renderings of voids in the alloy. The processed CT data was used to generate input files for use in finite element simulations, both two- and three-dimensional. The void analyses revealed that the overwhelming source of failure in each tensile bar was a ring of porosity within each bar, possibly due to a solidification front inherent to the casting process. The measured damage parameters related to void nucleation, growth, and coalescence were shown to contribute significantly to total damage accumulation. Void volume distributions were characterized using a Weibull function, and the spatial distributions of voids were shown to be clustered. Two-dimensional finite element analyses of the tensile bars were used to fine-tune material damage models and a three-dimensional mesh of an extracted portion of one tensile bar including voids was generated from CT data and used as input to a finite element analysis.« less

Mechanisms for Ductile Rupture - FY16 ESC Progress Report

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

Boyce, Brad L.; Carroll, Jay D.; Noell, Phillip

2017-01-01

Ductile rupture in metals is generally a multi-step process of void nucleation, growth, and coalescence. Particle decohesion and particle fracture are generally invoked as the primary microstructural mechanisms for room-temperature void nucleation. However, because high-purity materials also fail by void nucleation and coalescence, other microstructural features must also act as sites for void nucleation. Early studies of void initiation in high-purity materials, which included post-mortem fracture surface characterization using scanning electron microscopy (SEM) and high-voltage electron microscopy (HVEM) and in-situ HVEM observations of fracture, established the presence of dislocation cell walls as void initiation sites in high-purity materials. Direct experimentalmore » evidence for this contention was obtained during in-situ HVEM tensile tests of Be single crystals. Voids between 0.2 and 1 μm long appeared suddenly along dislocation cell walls during tensile straining. However, subsequent attempts to replicate these results in other materials, particularly α -Fe single crystals, were unsuccessful because of the small size of the dislocation cells, and these remain the only published in-situ HVEM observations of void nucleation at dislocation cell walls in the absence of a growing macrocrack. Despite this challenge, other approaches to studying void nucleation in high-purity metals also indicate that dislocation cell walls are nucleation sites for voids.« less

Effects of the spaces available for cations in strongly acidic cation-exchange resins on the exchange equilibria by quaternary ammonium ions and on the hydration states of metal ions.

PubMed

Watanabe, Yuuya; Ohnaka, Kenji; Fujita, Saki; Kishi, Midori; Yuchi, Akio

2011-10-01

The spaces (voids) available for cations in the five exchange resins with varying exchange capacities and cross-linking degrees were estimated, on the basis of the additivity of molar volumes of the constituents. Tetraalkylammonium ions (NR(4)(+); R: Me, Et, Pr) may completely exchange potassium ion on the resin having a larger void radius. In contrast, the ratio of saturated adsorption capacity to exchange capacity of the resin having a smaller void radius decreased with an increase in size of NR(4)(+) ions, due to the interionic contacts. Alkali metal ions could be exchanged quantitatively. While the hydration numbers of K(+), Rb(+), and Cs(+) were independent of the void radius, those of Li(+) and Na(+), especially Na(+), decreased with a decrease in void radius. Interionic contacts between the hydrated ions enhance the dehydration. Multivalent metal ions have the hydration numbers, comparable to or rather greater than those in water. A greater void volume available due to exchange stoichiometry released the interionic contacts and occasionally promoted the involvement of water molecules other than directly bound molecules. The close proximity between ions in the conventional ion-exchange resins having higher exchange capacities may induce varying interactions.

SIMULTANEOUS URODYNAMIC AND ANORECTAL MANOMETRY STUDIES IN CHILDREN: INSIGHTS INTO THE RELATIONSHIP BETWEEN THE LOWER GASTROINTESTINAL AND LOWER URINARY TRACTS

PubMed Central

Ambartsumyan, Lusine; Siddiqui, Anees; Bauer, Stuart; Nurko, Samuel

2016-01-01

Background Children with urinary incontinence (UI) have associated functional constipation (FC) and fecal incontinence (FI). The physiology between lower urinary tract (LUT) and anorectum in children has not been elucidated. Aims Observe the effect of rectal distention (RD) on LUT function, and bladder filling and voiding on anorectal function. Methods Children with voiding dysfunction referred to Boston Children’s Hospital were prospectively enrolled for combined urodynamic (UDS) and anorectal manometry (ARM). Anorectal and urodynamic parameters were simultaneously measured. Patients underwent 2 micturition cycles, 1st with rectal balloon deflated and 2nd with it inflated (RD). LUT and anorectal parameters were compared between cycles. Key Results 10 children (7 UI, 4 recurrent UTIs, 9 FC ± FI) were enrolled. Post void residual (PVR) increased (p=0.02) with RD. No differences were observed in percent of bladder filling to expected bladder capacity, sensation, and bladder compliance with and without RD. Bladder and abdominal pressures increased at voiding with RD (p<0.05). Intra-anal pressures decreased at voiding (p<0.05), at 25% (p=0.03) and 50% (p=0.06) of total volume of bladder filling. Conclusions & Inferences The PVR volume increased with RD. Stool in the rectum does not alter filling cystometric capacity but decreases the bladder’s ability to empty predisposing patients with fecal retention to UI and UTIs. Bladder and abdominal pressures increased during voiding demonstrating a physiological correlate of dysfunctional voiding. Intra-anal pressures decreased during bladder filling and voiding. This is the first time intra-anal relaxation during bladder filling and voiding has been described. PMID:27214097

Morphological transformation of soot: investigation of microphysical processes during the condensation of sulphuric acid and limonene ozonolysis products vapours

NASA Astrophysics Data System (ADS)

Pathak, R. K. P.; Pei, X.; Hallquist, M.; Pagels, J. H.

2017-12-01

Morphological transformation of soot particle by condensation of low volatility materials on it is a dominant atmospheric process with serious implications for its optical and hygroscopic properties, and atmospheric lifetime. In this study, the morphological transformation of soot agglomerate under the influence of condensation of vapours of sulphuric acid, and/or limonene ozonolysis products were investigated systematically using a Differential Mobility Analyser-Aerosol Particle Mass Analyser (DMA-APM) and the Tandem DMA techniques integrated with a laminar flow-tube system. We discovered that the morphology transformation of soot in general was a sequence of two-step process, i.e. (i) filling of void space within soot agglomerate; (ii) growth of particle diameter. These two steps followed and complimented each other. In the very beginning the filling was the dominant process followed by growth until it led to the accumulation of enough material that in turn exerted surface forces that eventually facilitated the further filling. The filling of void space was constrained by the initial morphology of fresh soot and the nature and amount of the material condensed. This process continued in several sequential steps until all void space within the soot agglomerate was filled completely and then growth of a spherical particle continued as long as mass was condensed on it. In this study, we developed a framework to quantify the microphysical transformation of soot upon the condensation of various materials. The framework utilized experimental data and hypothesis of ideal sphere growth and filling of voids to quantify the distribution of condensed materials in these two processes complimenting each other. Using this framework, we have quantified the percentage of material that went into processes of particle growth and void filling at each step. Using the same framework, we further estimated the fraction of internal voids and open voids and used this information to derive the volume equivalent diameter of soot agglomerate containing internal voids and calculated in-situ dynamic shape factor. Our study is the first study that tracks in situ microphysical changes in soot morphology quantitatively, providing the detailed status of both fresh and coated soot particles.

Direct observation of void evolution during cement hydration

DOE PAGES

Moradian, Masoud; Hu, Qinang; Aboustait, Mohammed; ...

2017-09-28

This study follows the hydration of both portland cement and tricalcium silicate pastes between 30 min and 16 h of hydration. In-situ fast X-ray Computed Tomography (fCT) was used to make direct observations of the air-filled void formation in w/s of 0.40 to 0.70 with a micron resolution. The results show that over the first hour of the acceleration period the volume of air-filled voids reaches a maximum value and then decreases during the acceleration period and stays constant. The void distribution changes from a few coarse voids to a large number of smaller and more uniformly distributed voids. Thismore » behavior is suggested to be controlled by changes in the ionic strength that cause exsolution of dissolved air from the pore solution.« less

Direct observation of void evolution during cement hydration

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

Moradian, Masoud; Hu, Qinang; Aboustait, Mohammed

This study follows the hydration of both portland cement and tricalcium silicate pastes between 30 min and 16 h of hydration. In-situ fast X-ray Computed Tomography (fCT) was used to make direct observations of the air-filled void formation in w/s of 0.40 to 0.70 with a micron resolution. The results show that over the first hour of the acceleration period the volume of air-filled voids reaches a maximum value and then decreases during the acceleration period and stays constant. The void distribution changes from a few coarse voids to a large number of smaller and more uniformly distributed voids. Thismore » behavior is suggested to be controlled by changes in the ionic strength that cause exsolution of dissolved air from the pore solution.« less

Cosmology with void-galaxy correlations.

PubMed

Hamaus, Nico; Wandelt, Benjamin D; Sutter, P M; Lavaux, Guilhem; Warren, Michael S

2014-01-31

Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute clustering amplitude of high-density regions mapped out by galaxy surveys, we propose a relative measurement that compares those to the underdense regions, cosmic voids. On the basis of realistic mock catalogs we demonstrate that cross correlating galaxies and voids opens up the possibility to calibrate galaxy bias and to define a static ruler thanks to the observable geometric nature of voids. We illustrate how the clustering of voids is related to mass compensation and show that volume-exclusion significantly reduces the degree of stochasticity in their spatial distribution. Extracting the spherically averaged distribution of galaxies inside voids from their cross correlations reveals a remarkable concordance with the mass-density profile of voids.

Time dependent voiding mechanisms in polyamide 6 submitted to high stress triaxiality: experimental characterisation and finite element modelling

NASA Astrophysics Data System (ADS)

Selles, Nathan; King, Andrew; Proudhon, Henry; Saintier, Nicolas; Laiarinandrasana, Lucien

2017-08-01

Double notched round bars made of semi-crystalline polymer polyamide 6 (PA6) were submitted to monotonic tensile and creep tests. The two notches had a root radius of 0.45 mm, which imposes a multiaxial stress state and a state of high triaxiality in the net (minimal) section of the specimens. Tests were carried out until the failure occurred from one of the notches. The other one, unbroken but deformed under steady strain rate or steady load, was inspected using the Synchrotron Radiation Computed Tomography (SRCT) technique. These 3D through thickness inspections allowed the study of microstructural evolution at the peak stress for the monotonic tensile test and at the beginning of the tertiary creep for the creep tests. Cavitation features were assessed with a micrometre resolution within the notched region. Spatial distributions of void volume fraction ( Vf) and void morphology were studied. Voiding mechanisms were similar under steady strain rates and steady loads. The maximum values of Vf were located between the axis of revolution of the specimens and the notch surface and voids were considered as flat cylinders with a circular basis perpendicular to the loading direction. A model, based on porous plasticity, was used to simulate the mechanical response of this PA6 material under high stress triaxiality. Both macroscopic behaviour (loading curves) and voiding micro-mechanisms (radial distributions of void volume fraction) were accurately predicted using finite element simulations.

Voids characteristics of asphaltic concrete containing coconut shell

NASA Astrophysics Data System (ADS)

Ezree Abdullah, Mohd; Hannani Madzaili, Amirah; Putra Jaya, Ramadhansyah; Yaacob, Haryati; Hassan, Norhidayah Abdul; Nazri, Fadzli Mohamed

2017-07-01

Asphalt durability is often linked to the thickness of the asphalt coating on the aggregate particles. In order to have adequate film thickness in asphaltic concrete, there must be sufficient space between the aggregate particles in the compacted pavement. This void space is referred to as voids in total mix (VTM), voids with filled bitumen (VFB), and voids in mineral aggregate (VMA). Hence, this study investigates the performance of coconut shell (CS) as coarse aggregate replacement on voids characteristics of asphaltic concrete. Four CS were used as coarse aggregates replacement in asphalt mixture namely 0%, 10%, 20%, 30%, and 40% (by weight volume). The voids properties of asphalt mixture were determined based on Marshall Mix design test. Test results show that VTM and VMA values were decrease with the increasing bitumen content where VFB was increase with increasing bitumen content. Furthermore, increasing the percentage of coconut shell in asphalt mixture was found to increases the voids value up to a peak level and then decreases with further additions of CS.

Mechanical Properties of Misers Bluff Sand.

DTIC Science & Technology

1986-09-01

in Chapter 4. 4 .7 Y~ e -~1 % CHAPTER 2 LABORATORY TESTS 2.1 CONVENTIONAL SOIL TESTS Samples of MB sand were split from the available supply of...air Va , and void ratio e (the ratio of void volume to solid volume). These composition data are listed in Table 2.1 for each test. 5 2.3 MECHANICAL...and diameter changes are made. The data can be plotted as principal stress difference versus axial strain, the slope of which is Young’s modulus E

[Physiotherapy in Women with Overactive Bladder].

PubMed

Henscher, U; Tholen, R; Kirschner-Hermanns, R

2016-08-01

As regards treatment for overactive bladder, physiotherapeutic interventions can be seen as an alternative to drug treatment. Targeted pelvic floor and bladder training is used to decrease the number of voids and the incontinence episodes or to increase the average voided volume in women with overactive bladder (3 systematic reviews with evidence level 1/1a).An additional option to treat women with overactive bladder is to use functional electrical stimulation and magnetic stimulation.2 systematic reviews 1 2 and 2 RCTs 3 4 reveal a low level of evidence (2 studies with level 2/2b) for the use of electrical stimulation (transcutaneous, vaginal or transanal) to reduce incontinence episodes and the number of voids and to increase the average voided volume. The trial from Yamanishi et al. (2014) shows that magnetic stimulation has a positive effect 5. Further studies are needed to evaluate the benefit of conservative treatment procedures for overactive bladder. © Georg Thieme Verlag KG Stuttgart · New York.

Voids and constraints on nonlinear clustering of galaxies

NASA Technical Reports Server (NTRS)

Vogeley, Michael S.; Geller, Margaret J.; Park, Changbom; Huchra, John P.

1994-01-01

Void statistics of the galaxy distribution in the Center for Astrophysics Redshift Survey provide strong constraints on galaxy clustering in the nonlinear regime, i.e., on scales R equal to or less than 10/h Mpc. Computation of high-order moments of the galaxy distribution requires a sample that (1) densely traces the large-scale structure and (2) covers sufficient volume to obtain good statistics. The CfA redshift survey densely samples structure on scales equal to or less than 10/h Mpc and has sufficient depth and angular coverage to approach a fair sample on these scales. In the nonlinear regime, the void probability function (VPF) for CfA samples exhibits apparent agreement with hierarchical scaling (such scaling implies that the N-point correlation functions for N greater than 2 depend only on pairwise products of the two-point function xi(r)) However, simulations of cosmological models show that this scaling in redshift space does not necessarily imply such scaling in real space, even in the nonlinear regime; peculiar velocities cause distortions which can yield erroneous agreement with hierarchical scaling. The underdensity probability measures the frequency of 'voids' with density rho less than 0.2 -/rho. This statistic reveals a paucity of very bright galaxies (L greater than L asterisk) in the 'voids.' Underdensities are equal to or greater than 2 sigma more frequent in bright galaxy samples than in samples that include fainter galaxies. Comparison of void statistics of CfA samples with simulations of a range of cosmological models favors models with Gaussian primordial fluctuations and Cold Dark Matter (CDM)-like initial power spectra. Biased models tend to produce voids that are too empty. We also compare these data with three specific models of the Cold Dark Matter cosmogony: an unbiased, open universe CDM model (omega = 0.4, h = 0.5) provides a good match to the VPF of the CfA samples. Biasing of the galaxy distribution in the 'standard' CDM model (omega = 1, b = 1.5; see below for definitions) and nonzero cosmological constant CDM model (omega = 0.4, h = 0.6 lambda(sub 0) = 0.6, b = 1.3) produce voids that are too empty. All three simulations match the observed VPF and underdensity probability for samples of very bright (M less than M asterisk = -19.2) galaxies, but produce voids that are too empty when compared with samples that include fainter galaxies.

Low dose oral desmopressin for nocturnal polyuria in patients with benign prostatic hyperplasia: a double-blind, placebo controlled, randomized study.

PubMed

Wang, Chung-Jing; Lin, Yu-Nan; Huang, Shi-Wei; Chang, Chien-Hsing

2011-01-01

We evaluated the long-term efficacy and safety of low dose oral desmopressin in elderly patients with benign prostatic hyperplasia with more than nocturnal voids and nocturnal polyuria more than 30% of total daily urine volume. Eligible patients with benign prostatic hyperplasia older than 65 years with nocturia, nocturnal polyuria and International Prostate Symptom Score 14 or greater were included in the study. All patients received placebo or 0.1 mg desmopressin orally at bedtime. Patients were required to visit the outpatient clinic from the first visit, and after 1, 3, 6 and 12 months of treatment. Patients maintained flow volume charts and used diaries to record voiding data throughout the study. During followup urinalysis, urine sodium, urine osmolality, serum electrolytes, prostate specific antigen, International Prostate Symptom Score, quality of life, transrectal ultrasonography of prostate, uroflowmetry and post-void residual urine volume were performed at each visit. A total of 115 patients were enrolled in the study and randomized as 58 in the placebo group and 57 in the desmopressin group. Desmopressin significantly decreased nocturnal urine output and the number of nocturia episodes, and prolonged the first sleep period (p < 0.01). Compared to before treatment desmopressin gradually decreased serum sodium and induced statistically but not clinically significant hyponatremia after 12 months of treatment. No serious systemic complications were found during medication. Low dose oral desmopressin is an effective and well tolerated treatment for nocturnal polyuria in the lower urinary tract symptoms of patients with benign prostatic hyperplasia. Long-term desmopressin therapy gradually decreases serum sodium and it might induce hyponatremia even in patients without initial hyponatremia. For long-term desmopressin administration serum sodium should be assessed carefully, at least at 1 week after treatment. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Phase relationship in three-phase composites which include a void phase

NASA Technical Reports Server (NTRS)

Price, H. L.; Nelson, J. B.

1976-01-01

The paper shows the relationship among polymer, particles, and voids in a three-phase composite and how some of the properties of a composite may be changed by changing the proportions of the phases. The three-phase composite is an aggregate of microspheres bonded together with a small amount of polymer which may not form a continuous matrix. The void space (third phase) is obtained by limiting the amount of polymer which is mixed with the microspheres. A ternary phase diagram is used to show the proportional relationship among the three phases, with each apex representing a volume fraction of unity for a constituent while the side opposite the apex represents a volume fraction of zero for that constituent. The vertical dimension represents some composite property such as density or strength. The effect of composition on composite properties is shown by plotting them on a binary phase diagram which represents a perpendicular plane coincident with the 0.60 volume fraction microsphere line.

Sacral root neuromodulation in idiopathic nonobstructive chronic urinary retention.

PubMed

Shaker, H S; Hassouna, M

1998-05-01

Sacral root neuromodulation is becoming a superior alternative to the standard treatment of idiopathic nonobstructive urinary retention. We report results in 20 successive patients who underwent sacral foramen implantation to restore bladder function. After an initial, thorough baseline assessment 20 patients 19.43 to 55.66 years old with idiopathic nonobstructive urinary retention underwent percutaneous nerve evaluation. Response was assessed by a detailed voiding diary. Responders underwent implantation with an S3 foramen implant, and were followed 1, 3 and 6 months postoperatively, and every 6 months thereafter. Sacral root neuromodulation restored voiding capability in these patients. Bladders were emptied with minimal post-void residual urine, which decreased from 78.3 to 5.5 to 10.2% of the total voided volume from baseline to postoperative followup. These results were reflected in uroflowmetry and pressure-flow studies, which were almost normal after implantation. Furthermore, the urinary tract infection rate decreased significantly and associated pelvic pain improved substantially. The Beck depression inventory and SF-36 quality of life questionnaire indicated some improvement but reached significance in only 1 item. In addition, cystometrography showed no significant difference after 6 months of implantation compared with baseline values. Complications were minimal and within expectations. Sacral root neuromodulation is an appealing, successful modality for nonobstructive urinary retention. Only patients who have a good response to percutaneous nerve evaluation are candidates for implantation. The high efficacy in patients who undergo implantation, relative simplicity of the procedure and low complication rate make this a treatment breakthrough in this difficult group.

International Space Station Urine Monitoring System Functional Integration and Science Testing

NASA Technical Reports Server (NTRS)

Rodriguez, Branelle R.; Broyan, James Lee, Jr.

2008-01-01

Exposure to microgravity during human spaceflight is required to be defined and understood as the human exploration of space requires longer duration missions. It is known that long term exposure to microgravity causes bone loss. Urine voids are capable of measuring the calcium and other metabolic byproducts in a constituent s urine. The International Space Station (ISS) Urine Monitoring System (UMS) is an automated urine collection device designed to collect urine, separate the urine and air, measure the void volume, and allow for syringe sampling. Accurate measuring and minimal cross contamination is essential to determine bone loss and the effectiveness of countermeasures. The ISS UMS provides minimal cross contamination (<0.7 ml urine) and has volume accuracy of +/-2% between 100 to 1000 ml urine voids.

International Space Station Urine Monitoring System Functional Integration and Science Testing

NASA Technical Reports Server (NTRS)

Cibuzar, Branelle R.; Broyan, James Lee, Jr.

2009-01-01

Exposure to microgravity during human spaceflight is required to be defined and understood as the human exploration of space requires longer duration missions. It is known that long term exposure to microgravity causes bone loss. Urine voids are capable of measuring the calcium and other metabolic byproducts in a constituent s urine. The International Space Station (ISS) Urine Monitoring System (UMS) is an automated urine collection device designed to collect urine, separate the urine and air, measure the void volume, and allow for syringe sampling. Accurate measuring and minimal cross contamination is essential to determine bone loss and the effectiveness of countermeasures. The ISS UMS provides minimal cross contamination (<0.7 ml urine) and has volume accuracy of +/-2% between 100 to 1000 ml urine voids.

Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

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

Herring, Stuart Davis; Germann, Timothy C; Jensen, Niels G

2010-01-01

The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4. The transition at larger velocities to detonation is studied in amore » micron-long sample with a single void (and its periodic images). The reaction yield during the shock traversal increases rapidly with velocity, then becomes a prompt, reliable detonation. A void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal. A Pop plot of the time-to-detonation at higher velocities shows a characteristic pressure dependence.« less

Regenerator performance in a Vuilleumier refrigerator compared with a third-order numerical model

NASA Technical Reports Server (NTRS)

Bradley, P. E.; Radebaugh, Ray; Gary, John

1991-01-01

A three-stage Vuilleumier refrigerator was used to measure the performance of various third stage regenerators. The refrigerator operates between 2.5 and 5.0 Hz and, depending on the material used in the third stage regenerator, achieves temperatures of 8 to 20 K at the cold end of the third stage. This paper presents a comparison of regenerator performance for four regenerator materials: 229 micron diameter spheres of Pb(+)5 pct Sb, 229 micron diameter spheres of brass, 216 micron irregularly-shaped GdRh powder, and a mixture of 229 microns and 762 microns diameter spheres of Pb(+5) pct Sb. The experimental results are compared with a first-order model that neglects the void volume within the regenerator and with a third-order model that considers the effect of pressure oscillations in the regenerator void volume. Experimental results indicate that regenerator losses are dominated by the pressure oscillation in the void volume rather than the mass flow through the temperature gradient in the regenerator. These results are consistent with the third-order numerical model. This model shows that the heat capacity of the gas in the void space as well as the heat capacity of the matrix influences the regenerator performance.

Electromigration Mechanism of Failure in Flip-Chip Solder Joints Based on Discrete Void Formation.

PubMed

Chang, Yuan-Wei; Cheng, Yin; Helfen, Lukas; Xu, Feng; Tian, Tian; Scheel, Mario; Di Michiel, Marco; Chen, Chih; Tu, King-Ning; Baumbach, Tilo

2017-12-20

In this investigation, SnAgCu and SN100C solders were electromigration (EM) tested, and the 3D laminography imaging technique was employed for in-situ observation of the microstructure evolution during testing. We found that discrete voids nucleate, grow and coalesce along the intermetallic compound/solder interface during EM testing. A systematic analysis yields quantitative information on the number, volume, and growth rate of voids, and the EM parameter of DZ*. We observe that fast intrinsic diffusion in SnAgCu solder causes void growth and coalescence, while in the SN100C solder this coalescence was not significant. To deduce the current density distribution, finite-element models were constructed on the basis of the laminography images. The discrete voids do not change the global current density distribution, but they induce the local current crowding around the voids: this local current crowding enhances the lateral void growth and coalescence. The correlation between the current density and the probability of void formation indicates that a threshold current density exists for the activation of void formation. There is a significant increase in the probability of void formation when the current density exceeds half of the maximum value.

Influence of regenerator void volume on performance of a precooled 4 K Stirling type pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Li, Zhuopei; Jiang, Yanlong; Gan, Zhihua; Qiu, Limin; Chen, Jie

2015-09-01

Stirling type pulse tube cryocoolers (SPTC), typically operating at 30-60 Hz, have the advantage of compact structure, light weight, and long life compared with Gifford-McMahon type (1-2 Hz) PTC (GMPTC). The behavior of flow and heat transfer in the regenerator of a 4 K SPTC deviates from that at warmer temperatures and low frequencies. In this paper the behavior of 4 K regenerator at high frequencies is investigated based on a single-stage 4 K SPTC precooled by a two-stage GMPTC. The 4 K SPTC and the GMPTC is thermally coupled with two thermal bridges. The 4 K SPTC uses a 10 K cold inertance tube as phase shifter to improve phase relationship between mass flow and pressure. The regenerator void volume is an important factor that significantly influences the heat transfer between regenerator matrix and working fluid helium, pressure drop along the regenerator, and phase shift between mass flow and pressure. In this paper, influence of regenerator void volume on the performance of the 4 K SPTC with different operating parameters including operating frequencies and average pressure is studied theoretically and experimentally. The first and second precooling powers provided by the GMPTC are obtained which are important parameters to evaluate the efficiency of the whole 4 K system with precooling. The results of the regenerator void volume are given and discussed in normalized form for general use.

Carbon-shell-constrained silicon cluster derived from Al-Si alloy as long-cycling life lithium ion batteries anode

NASA Astrophysics Data System (ADS)

Su, Junming; Zhang, Congcong; Chen, Xiang; Liu, Siyang; Huang, Tao; Yu, Aishui

2018-03-01

Although silicon is the most promising anode material for Li-ion batteries, large volume expansion during lithiation and delithiation is the main obstacle limiting the commercial application of silicon anodes. There are two ways to alleviate volume expansion and prevent further pulverization of a Si anode: fabrication of a rational nanostructure possessing void spaces and uniform distribution of the conducting sites, without a good balance effect in mitigating the limiting factors and enhancing battery performance. In this paper, we propose a novel nanostructure - a carbon-shell-constrained Si cluster (Si/C shell) with both adequate void space and good distribution of electrical contact sites to guarantee homogeneous lithiation in the initial cycle. Benefiting from the ability to maintain electrical conductivity of the outer carbon shell, even after cluster fragmentation, the Si/C shell synthesized from low-cost commercial Al-Si alloy spheres can deliver 0.03% capacity loss from 100th to 1000th cycles at a current density of 1 A g-1. The Si/C shell sample with the dual functional structure mentioned above can also maintain its own nanostructure during cycling and deliver excellent rate performance. It is a concise and scalable strategy which can simplify the preparation of other alloy anode materials for Li-ion batteries.

Micron-scale Reactive Atomistic Simulation of Void Collapse and Hotspot Growth in PETN

NASA Astrophysics Data System (ADS)

Thompson, Aidan; Shan, Tzu-Ray; Wixom, Ryan

2015-06-01

Material defects and other heterogeneities such as dislocations, micro-porosity, and grain boundaries play key roles in the shock-induced initiation of detonation in energetic materials. We performed non-equilibrium molecular dynamics simulations to explore the effect of nanoscale voids on hotspot growth and initiation in micron-scale pentaerythritol tetranitrate (PETN) crystals under weak shock loading (Up = 1.25 km/s; Us = 4.5 km/s). We used the ReaxFF potential implemented in LAMMPS. We built a pseudo-2D PETN crystal with dimensions 0.3 μm × 0.22 μm × 1.3 nm containing a 20 nm cylindrical void. Once the initial shockwave traversed the entire sample, the shock-front absorbing boundary condition was applied, allowing the simulation to continue beyond 1 nanosecond. Results show an exponentially increasing hotspot growth rate. The hotspot morphology is initially symmetric about the void axis, but strong asymmetry develops at later times, due to strong coupling between exothermic chemistry, temperature, and divergent secondary shockwaves emanating from the collapsing void. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Redshift-space distortions around voids

NASA Astrophysics Data System (ADS)

Cai, Yan-Chuan; Taylor, Andy; Peacock, John A.; Padilla, Nelson

2016-11-01

We have derived estimators for the linear growth rate of density fluctuations using the cross-correlation function (CCF) of voids and haloes in redshift space. In linear theory, this CCF contains only monopole and quadrupole terms. At scales greater than the void radius, linear theory is a good match to voids traced out by haloes; small-scale random velocities are unimportant at these radii, only tending to cause small and often negligible elongation of the CCF near its origin. By extracting the monopole and quadrupole from the CCF, we measure the linear growth rate without prior knowledge of the void profile or velocity dispersion. We recover the linear growth parameter β to 9 per cent precision from an effective volume of 3( h-1Gpc)3 using voids with radius >25 h-1Mpc. Smaller voids are predominantly sub-voids, which may be more sensitive to the random velocity dispersion; they introduce noise and do not help to improve measurements. Adding velocity dispersion as a free parameter allows us to use information at radii as small as half of the void radius. The precision on β is reduced to 5 per cent. Voids show diverse shapes in redshift space, and can appear either elongated or flattened along the line of sight. This can be explained by the competing amplitudes of the local density contrast, plus the radial velocity profile and its gradient. The distortion pattern is therefore determined solely by the void profile and is different for void-in-cloud and void-in-void. This diversity of redshift-space void morphology complicates measurements of the Alcock-Paczynski effect using voids.

High Temperature VARTM of Phenylethynyl Terminated Imides

NASA Technical Reports Server (NTRS)

Ghose, Sayata; Watson, Kent A.; Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.

2009-01-01

LaRC phenylethynyl terminated imide (PETI) resins were processed into composites using high temperature vacuum assisted resin transfer molding (VARTM). Although initial runs yielded composites with high void content, process modifications reduced voids to <3%. Photomicrographs were taken and void contents and T(sub g)s of the panels were determined.

Development of a prototype fluid volume measurement system. [for urine volume measurement on space missions

NASA Technical Reports Server (NTRS)

Poppendiek, H. F.; Sabin, C. M.; Meckel, P. T.

1974-01-01

The research is reported in applying the axial fluid temperature differential flowmeter to a urine volume measurement system for space missions. The fluid volume measurement system is described along with the prototype equipment package. Flowmeter calibration, electronic signal processing, and typical void volume measurements are also described.

Shock induced damage in copper: A before and after, three-dimensional study

NASA Astrophysics Data System (ADS)

Menasche, David B.; Lind, Jonathan; Li, Shiu Fai; Kenesei, Peter; Bingert, John F.; Lienert, Ulrich; Suter, Robert M.

2016-04-01

We report on the microstructural features associated with the formation of incipient spall and damage in a fully recrystallized, high purity copper sample. Before and after ballistic shock loading, approximately 0.8 mm3 of the sample's crystal lattice orientation field is mapped using non-destructive near-field High Energy Diffraction Microscopy. Absorption contrast tomography is used to image voids after loading. This non-destructive interrogation of damage initiation allows for novel characterization of spall points vis-a-vis microstructural features and a fully 3D examination of microstructural topology and its influence on incipient damage. The spalled region is registered with and mapped back onto the pre-shock orientation field. As expected, the great majority of voids occur at grain boundaries and higher order microstructural features; however, we find no statistical preference for particular grain boundary types. The damaged region contains a large volume of Σ-3 (60 °<111 >) connected domains with a large area fraction of incoherent Σ-3 boundaries.

Quantifying Effects of Voids in Woven Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

2013-01-01

Randomness in woven ceramic matrix composite architecture has been found to cause large variability in stiffness and strength. The inherent voids are an aspect of the architecture that may cause a significant portion of the variability. A study is undertaken to investigate the effects of many voids of random sizes and distributions. Response surface approximations were formulated based on void parameters such as area and length fractions to provide an estimate of the effective stiffness. Obtaining quantitative relationships between the properties of the voids and their effects on stiffness of ceramic matrix composites are of ultimate interest, but the exploratory study presented here starts by first modeling the effects of voids on an isotropic material. Several cases with varying void parameters were modeled which resulted in a large amount of variability of the transverse stiffness and out-of-plane shear stiffness. An investigation into a physical explanation for the stiffness degradation led to the observation that the voids need to be treated as an entity that reduces load bearing capabilities in a space larger than what the void directly occupies through a corrected length fraction or area fraction. This provides explanation as to why void volume fraction is not the only important factor to consider when computing loss of stiffness.

Poisson-Nernst-Planck-Fermi theory for modeling biological ion channels

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

Liu, Jinn-Liang, E-mail: jinnliu@mail.nhcue.edu.tw; Eisenberg, Bob, E-mail: beisenbe@rush.edu

2014-12-14

A Poisson-Nernst-Planck-Fermi (PNPF) theory is developed for studying ionic transport through biological ion channels. Our goal is to deal with the finite size of particle using a Fermi like distribution without calculating the forces between the particles, because they are both expensive and tricky to compute. We include the steric effect of ions and water molecules with nonuniform sizes and interstitial voids, the correlation effect of crowded ions with different valences, and the screening effect of water molecules in an inhomogeneous aqueous electrolyte. Including the finite volume of water and the voids between particles is an important new part ofmore » the theory presented here. Fermi like distributions of all particle species are derived from the volume exclusion of classical particles. Volume exclusion and the resulting saturation phenomena are especially important to describe the binding and permeation mechanisms of ions in a narrow channel pore. The Gibbs free energy of the Fermi distribution reduces to that of a Boltzmann distribution when these effects are not considered. The classical Gibbs entropy is extended to a new entropy form — called Gibbs-Fermi entropy — that describes mixing configurations of all finite size particles and voids in a thermodynamic system where microstates do not have equal probabilities. The PNPF model describes the dynamic flow of ions, water molecules, as well as voids with electric fields and protein charges. The model also provides a quantitative mean-field description of the charge/space competition mechanism of particles within the highly charged and crowded channel pore. The PNPF results are in good accord with experimental currents recorded in a 10{sup 8}-fold range of Ca{sup 2+} concentrations. The results illustrate the anomalous mole fraction effect, a signature of L-type calcium channels. Moreover, numerical results concerning water density, dielectric permittivity, void volume, and steric energy provide useful details to study a variety of physical mechanisms ranging from binding, to permeation, blocking, flexibility, and charge/space competition of the channel.« less

An investigation of the plastic fracture of high strength steels. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Cox, T. B.; Low, J. R., Jr.

1973-01-01

Three generally recognized stages of plastic fracture in high strength steels are considered in detail. These stages consist of void initiation, void growth, and void coalescence. A brief review of the existing literature on plastic fracture is included along with an outline of the experimental approach used in the investigation.

Design of pellet surface grooves for fission gas plenum

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

Carter, T.J.; Jones, L.R.; Macici, N.

1986-01-01

In the Canada deuterium uranium pressurized heavy water reactor, short (50-cm) Zircaloy-4 clad bundles are fueled on-power. Although internal void volume within the fuel rods is adequate for the present once-through natural uranium cycle, the authors have investigated methods for increasing the internal gas storage volume needed in high-power, high-burnup, experimental ceramic fuels. This present work sought to prove the methodology for design of gas storage volume within the fuel pellets - specifically the use of grooves pressed or machined into the relatively cool pellet/cladding interface. Preanalysis and design of pellet groove shape and volume was accomplished using the TRUMPmore » heat transfer code. Postirradiation examination (PIE) was used to check the initial design and heat transfer assumptions. Fission gas release was found to be higher for the grooved pellet rods than for the comparison rods with hollow or unmodified pellets. This had been expected from the initial TRUMP thermal analyses. The ELESIM fuel modeling code was used to check in-reactor performance, but some modifications were necessary to accommodate the loss of heat transfer surface to the grooves. It was concluded that for plenum design purposes, circumferential pellet grooves could be adequately modeled by the codes TRUMP and ELESIM.« less

Demonstration of Aflatoxin Inhibitory Activity in a Cotton Seed Coat Xylan

PubMed Central

Mellon, J. E.; Cotty, P. J.; Godshall, M. A.; Roberts, E.

1995-01-01

An inhibitor of aflatoxin biosynthesis localized in the seed coats of developing cotton was partially purified and characterized. Aqueous extracts from 25-day postanthesis seed coat tissue inhibited aflatoxin (B(inf1)) production in liquid cultures of Aspergillus flavus AF13. Inhibition was concentration dependent, with a 50% effective dose of 173 (mu)g of crude extract per ml of medium. The inhibitor was neutral in charge. Two active fractions were obtained from crude preparations by gel filtration chromatography (BioGel P-100). The purest fraction eluted in the void volume. Carbohydrate composition analysis of this void volume inhibitor indicated a composition of xylose (>90%) and mannose. Aflatoxin production in vitro was inversely related to inhibitor concentration in the fermentation medium (log of aflatoxin versus log of [inhibitor]; r(sup2) = 0.82; P < 0.002). The void volume inhibitor had a 50% effective dose of 6.2 (mu)g/ml, a 28-fold purification of the inhibitor material. These data support the hypothesis that seed coat inhibitory activity is associated with a cottonseed-specific xylan. PMID:16535194

Morphological Segregation in the Surroundings of Cosmic Voids

NASA Astrophysics Data System (ADS)

Ricciardelli, Elena; Cava, Antonio; Varela, Jesus; Tamone, Amelie

2017-09-01

We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R void, which we define as the region of influence of voids. The significance of this difference is greater than 3σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

An investigation of voids formation mechanisms and their effects on freeze and thaw processes of lithium and lithium fluoride

NASA Technical Reports Server (NTRS)

El-Genk, Mohamed S.; Yang, Jae-Young

1991-01-01

The mechanisms of void formation during the cooldown and freezing of lithium coolant within the primary loop of SP-100 type systems are investigated. These mechanisms are: (1) homogeneous nucleation; (2) heterogeneous nucleation; (3) normal segregation of helium gas dissolved in liquid lithium; and (4) shrinkage of lithium during freezing. To evaluate the void formation potential due to segregation, a numerical scheme that couples the freezing and mass diffusion processes in both the solid and liquid regions is developed. The results indicated that the formation of He bubbles is unlikely by either homogeneous or heterogeneous nucleation during the cooldown process. However, homogeneous nucleation of He bubbles following the segregation of dissolved He in liquid lithium ahead of the solid-liquid interface is likely to occur. Results also show that total volume of He void is insignificant when compared to that of shrinkage voids. In viewing this, the subsequent research focuses on the effects of shrinkage void forming during freezing of lithium on subsequent thaw processes are investigated using a numerical scheme that is based on a single (solid/liquid) cell approach. The cases of lithium-fluoride are also investigated to show the effect of larger volume shrinkage upon freezing on the freeze and thaw processes. Results show that a void forming at the wall appreciably reduces the solid-liquid interface velocity, during both freeze and thaw, and causes a substantial rise in the wall temperature during thaw. However, in the case of Li, the maximum wall temperature was much lower than the melting temperature of PWC-11, which is used as the structure material in the SP-100 system. Hence, it is included that a formation of hot spots is unlikely during the startup or restart of the SP-100 system.

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

Potter, David Charles; Taylor, Craig Michael; Coons, James Elmer

The percent void of the Fort Saint Vrain (FSV) material is estimated to be 21.1% based on the volume of the gap at the top of the drums, the volume of the coolant channels in the FSV fuel element, and the volume of the fuel handling channel in the FSV fuel element.

Theory of void formation in dusty plasmas

NASA Astrophysics Data System (ADS)

Hu, Zuquan; Chen, Yinhua; Zheng, Xiang; Huang, Feng; Shi, Gei-fen; Yu, M. Y.

2009-06-01

A fluid theory of void formation in dusty plasmas taking into account ionization is proposed. It is shown that if the ionization rate is larger than a threshold, an initial steady-state dust-density distribution can evolve into a stable distribution containing a void. As the ionization rate is further increased, the time required for void formation decreases. The void size first increases, but then decreases. However, for still larger ionization rates, the dusty region of the plasma becomes ringlike, including the convection term in dust momentum equation. The results are in agreement with existing experiments and theories.

Effect of Post Space Preparation on Apical Obturation Quality of Teeth Obturated with Different Techniques: A Micro-computed Tomographic Study.

PubMed

Küçükkaya Eren, Selen; Askerbeyli Örs, Sevinc; Yılmaz, Zeliha

2017-07-01

The purpose of this study was to evaluate the obturation quality of root canals filled with different techniques and to determine whether post space preparation had an effect on the quality of apical obturation using micro-computed tomographic (micro-CT) imaging. The root canals of 30 human mandibular premolar teeth were instrumented, and the specimens were divided into 3 groups according to the obturation technique used: cold lateral compaction (CLC), warm vertical compaction (WVC), or single-cone (SC) techniques. The specimens were stored at 37°C and 100% humidity for 1 week. Then, the coronal root filling material was removed in order to create a post space. Micro-CT scans were performed before and after post space preparation for the volumetric analysis of voids and filling materials. Data were analyzed using repeated-measures analysis of variance and Bonferroni tests. The CLC and SC groups showed a significantly greater percentage volume of voids than the WVC group (P < .05), whereas no significant difference was found between the CLC and SC groups before and after post space preparation (P > .05). The post space preparation caused a significant increase in the percentage volume of voids in the CLC and SC groups (P < .05). No significant difference was detected in the percentage volume of voids in the WVC group after post space preparation (P > .05). No root fillings were void free. The WVC group presented the best obturation quality. The post space preparation negatively influenced the apical integrity of the filling materials in the CLC and SC groups, whereas it had no significant effect in the WVC group. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Changes in voiding behavior in a mouse model of Alzheimer’s disease

PubMed Central

Biallosterski, B. T.; Prickaerts, J.; Rahnama’i, M. S.; de Wachter, S.; van Koeveringe, G. A.; Meriaux, C.

2015-01-01

Besides cognitive decline and behavioral alteration, urinary incontinence often occurs in patients suffering from Alzheimer’s disease (AD). To determine whether the transgenic mouse model of AD, APP/PS1 (APPSL/PS1M146L) mouse, shows alteration of the urinary bladder function and anxiety, as for patients with AD, we examined the urinary marking behavior in relation to affective behavior. At 18 months of age voiding behavior of APP/PS1 and wild type (WT) mice was assessed by using a modified filter paper assay in combination with video tracing, with the cage divided into a center and corner zones. Anxiety-related behavior and locomotion were respectively tested in an elevated zero maze (EZM) and an open field (OF). The APP/PS1 mice urinated more in the center zone than the WT mice. The total volume of markings was significantly lower in the APP/PS1 mice. In both groups, the average volume of a marking in the corner zone was larger than in the center zone. In the EZM, the APP/PS1 mice spent less time in the open arms of the arena, considered as anxiogenic zones, than the WT mice. During the OF task, the APP/PS1 mice covered a longer distance than the WT mice. These findings show that the APP/PS1 mice have a different voiding behavior compared to the WT mice, i.e., urinating with small volumes and voiding in the center of the cage, and suggest that increased locomotor activity and anxiety-related behaviors are factors in the change in voiding pattern in the APP/PS1 mouse. PMID:26379542

Incorporation of the NAG-FRAG Model for Ductile and Brittle Fracture into Help, a 2D Multimaterial Eulerian Program

DTIC Science & Technology

1978-09-01

Models HELP Ductile Material HEMP Brittle Material PUFF Iron Aluminum Eulerian Codea Tap«.r«»H Flyor Pl^«-» rmp«^» tO. ABITRACT (Conllmjm M r«v... HEMP ) code with those obtained by the Eulerian (HELP) code 5.3 Relative void volume of damage regions at three times after impact in the 1145...plate calculation 5.5 Relative void volume of material in the 1145 aluminum target at 1.46 us after impact as computed by the Lagrangian ( HEMP

Force measurement-based discontinuity detection during friction stir welding

DOE PAGES

Shrivastava, Amber; Zinn, Michael; Duffie, Neil A.; ...

2017-02-23

Here, the objective of this work is to develop a method for detecting the creation of discontinuities ( i.e., voids, volume defects) during friction stir welding. Friction stir welding is inherently cost effective, however, the need for significant weld inspection can make the process cost prohibitive. A new approach to weld inspection is required in which an in situ characterization of weld quality can be obtained, reducing the need for postprocess inspection. To this end, friction stir welds with subsurface voids and without voids were created. The subsurface voids were generated by reducing the friction stir tool rotation frequency andmore » increasing the tool traverse speed in order to create “colder” welds. Process forces were measured during welding, and the void sizes were measured postprocess by computerized tomography ( i.e., 3D X-ray imaging). Two parameters, based on frequency domain content and time-domain average of the force signals, were found to be correlated with void size. Criteria for subsurface void detection and size prediction were developed and shown to be in good agreement with experimental observations. Furthermore, with the proper choice of data acquisition system and frequency analyzer the occurrence of subsurface voids can be detected in real time.« less

Force measurement-based discontinuity detection during friction stir welding

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

Shrivastava, Amber; Zinn, Michael; Duffie, Neil A.

Here, the objective of this work is to develop a method for detecting the creation of discontinuities ( i.e., voids, volume defects) during friction stir welding. Friction stir welding is inherently cost effective, however, the need for significant weld inspection can make the process cost prohibitive. A new approach to weld inspection is required in which an in situ characterization of weld quality can be obtained, reducing the need for postprocess inspection. To this end, friction stir welds with subsurface voids and without voids were created. The subsurface voids were generated by reducing the friction stir tool rotation frequency andmore » increasing the tool traverse speed in order to create “colder” welds. Process forces were measured during welding, and the void sizes were measured postprocess by computerized tomography ( i.e., 3D X-ray imaging). Two parameters, based on frequency domain content and time-domain average of the force signals, were found to be correlated with void size. Criteria for subsurface void detection and size prediction were developed and shown to be in good agreement with experimental observations. Furthermore, with the proper choice of data acquisition system and frequency analyzer the occurrence of subsurface voids can be detected in real time.« less

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

Ricciardelli, Elena; Tamone, Amelie; Cava, Antonio

We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found atmore » smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R {sub void}, which we define as the region of influence of voids. The significance of this difference is greater than 3 σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.« less

Voxel based parallel post processor for void nucleation and growth analysis of atomistic simulations of material fracture.

PubMed

Hemani, H; Warrier, M; Sakthivel, N; Chaturvedi, S

2014-05-01

Molecular dynamics (MD) simulations are used in the study of void nucleation and growth in crystals that are subjected to tensile deformation. These simulations are run for typically several hundred thousand time steps depending on the problem. We output the atom positions at a required frequency for post processing to determine the void nucleation, growth and coalescence due to tensile deformation. The simulation volume is broken up into voxels of size equal to the unit cell size of crystal. In this paper, we present the algorithm to identify the empty unit cells (voids), their connections (void size) and dynamic changes (growth and coalescence of voids) for MD simulations of large atomic systems (multi-million atoms). We discuss the parallel algorithms that were implemented and discuss their relative applicability in terms of their speedup and scalability. We also present the results on scalability of our algorithm when it is incorporated into MD software LAMMPS. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of Moisture Exchange on Interface Formation in the Repair System Studied by X-ray Absorption

PubMed Central

Lukovic, Mladena; Ye, Guang

2015-01-01

In concrete repair systems, material properties of the repair material and the interface are greatly influenced by the moisture exchange between the repair material and the substrate. If the substrate is dry, it can absorb water from the repair material and reduce its effective water-to-cement ratio (w/c). This further affects the hydration rate of cement based material. In addition to the change in hydration rate, void content at the interface between the two materials is also affected. In this research, the influence of moisture exchange on the void content in the repair system as a function of initial saturation level of the substrate is investigated. Repair systems with varying level of substrate saturation are made. Moisture exchange in these repair systems as a function of time is monitored by the X-ray absorption technique. After a specified curing age (3 d), the internal microstructure of the repair systems was captured by micro-computed X-ray tomography (CT-scanning). From reconstructed images, different phases in the repair system (repair material, substrate, voids) can be distinguished. In order to quantify the void content, voids were thresholded and their percentage was calculated. It was found that significantly more voids form when the substrate is dry prior to application of the repair material. Air, initially filling voids and pores of the dry substrate, is being released due to the moisture exchange. As a result, air voids remain entrapped in the repair material close to the interface. These voids are found to form as a continuation of pre-existing surface voids in the substrate. Knowledge about moisture exchange and its effects provides engineers with the basis for recommendations about substrate preconditioning in practice. PMID:28787801

Shock loading and reactive flow modeling studies of void induced AP/AL/HTPB propellant

NASA Astrophysics Data System (ADS)

Miller, P. J.; Lindfors, A. J.

1998-07-01

The unreactive Hugoniot of a class 1.3 propellant has been investigated by shock compression experiments. The results are analyzed in terms of an ignition and growth reactive flow model using the DYNA2D hydrocode. The calculated shock ignition parameters of the model show a linear dependence on measured void volume which appears to reproduce the observed gauge records well. Shock waves were generated by impact in a 75 mm single stage powder gun. Manganin and PVDF pressure gauges provided pressure-time histories to 140 kbar. The propellants were of similar formulation differing only in AP particle size and the addition of a burn rate modifer (Fe2O3) from that of previous investigations. Results show neglible effect of AP particle size on shock response in contrast to the addition of Fe2O3 which appears to `stiffen' the unreactive Hugoniot and enhances significantly the reactive rates under shock. The unreactive Hugoniot, within experimental error, compares favorably to the solid AP Hugoniot. Shock experiments were performed on propellant samples strained to induce insitu voids. The material state was quantified by uniaxial tension dialatometry. The experimental records show a direct correlation between void volume (0 to 1.7%) and chemical reactivity behind the shock front. These results are discussed in terms of `hot spot' ignition resulting from the shock collapse of the voids.

Three-dimensional simulations of void collapse in energetic materials

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Udaykumar, H. S.

2018-03-01

The collapse of voids in porous energetic materials leads to hot-spot formation and reaction initiation. This work advances the current knowledge of the dynamics of void collapse and hot-spot formation using 3D reactive void collapse simulations in HMX. Four different void shapes, i.e., sphere, cylinder, plate, and ellipsoid, are studied. For all four shapes, collapse generates complex three-dimensional (3D) baroclinic vortical structures. The hot spots are collocated with regions of intense vorticity. The differences in the vortical structures for the different void shapes are shown to significantly impact the relative sensitivity of the voids. Voids of high surface area generate hot spots of greater intensity; intricate, highly contorted vortical structures lead to hot spots of corresponding tortuosity and therefore enhanced growth rates of reaction fronts. In addition, all 3D voids are shown to be more sensitive than their two-dimensional (2D) counterparts. The results provide physical insights into hot-spot formation and growth and point to the limitations of 2D analyses of hot-spot formation.

Effect of local void morphology on the reaction initiation mechanism in the case of pressed HMX

NASA Astrophysics Data System (ADS)

Roy, Sidhartha; Rai, Nirmal; Udaykumar, H. S.

2017-06-01

The microstructural characteristics of pressed HMX has a significant effect on its sensitivity under shock loading. The microstructure of pressed HMX contains voids of various orientation and aspect ratio. Subject to shock loading, these voids can collapse forming hotspots and initiate chemical reaction. This work shows how the ignition and growth of chemical reaction is dependent on the local microstructural features of the voids. Morphological quantities like size, aspect ratio and orientations are extracted from the real microstructural images of Class III and Class V pressed HMX. These morphological quantities are correlated with the ignition and growth rates of the chemical reaction. The dependency of the sensitivity of a given HMX sample on the local morphological features shows that these local features can create a mocroscale physical response.

Effects of void anisotropy on the ignition and growth rates of energetic materials

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

2017-06-01

Initiation of heterogeneous energetic materials is thought to occur at hot spots; reaction fronts propagate from sites of such hot spots into the surrounding material resulting in complete consumption of the material. Heterogeneous materials, such as plastic bonded explosives (PBXs) and pressed materials contain numerous voids, defects and interfaces at which hot spots can occur. Amongst the various mechanisms of hot spot formation, void collapse is considered to be the predominant one in the high strain rate loading conditions. It is established in the past the shape of the voids has a significant effect on the initiation behavior of energetic materials. In particular, void aspect ratio and orientations play an important role in this regard. This work aims to quantify the effects of void aspect ratio and orientation on the ignition and growth rates of chemical reaction from the hot spot. A wide range of aspect ratio and orientations is considered to establish a correlation between the ignition and growth rates and the void morphology. The ignition and growth rates are obtained from high fidelity reactive meso-scale simulations. The energetic material considered in this work is HMX and Tarver McGuire HMX decomposition model is considered to capture the reaction mechanism of HMX. The meso-scale simulations are performed using a Cartesian grid based Eulerian solver SCIMITAR3D. The void morphology is shown to have a significant effect on the ignition and growth rates of HMX.

Hypothyroidism impairs somatovisceral reflexes involved in micturition of female rabbits.

PubMed

Sánchez-García, Octavio; López-Juárez, Rhode; Rodríguez-Castelán, Julia; Corona-Quintanilla, Dora L; Martínez-Gómez, Margarita; Cuevas-Romero, Estela; Castelán, Francisco

2018-04-17

To determine the impact of hypothyroidism on the bladder and urethral functions as well as in the activation of the pubococcygeous (Pcm) and bulbospongiosus (Bsm) during micturition. Age-matched control and methimazole-induced hypothyroid female rabbits were used to simultaneously record cystometrograms, urethral pressure, and the reflex activation of Pcm and Bsm during the induced micturition. Urodynamic and urethral variables were measured. Activation or no activation of the Pcm and Bsm during the storage and voiding phases of micturition were categorized as 1 or 0. Significant differences (P ≤ 0.05) between control and hypothyroid groups were determined with unpaired Student-t or Mann-Whitney tests. One-month induced hypothyroidism increased the residual volume and threshold pressure while the opposite was true for the voided volume, maximal pressure, and voiding efficiency. Urethral pressure was also affected as supported by a notorious augmentation of the urethral resistance, among other changes in the rest of measured variables. Hypothyroidism also affected the reflex activation of the Pcm in the voiding phase of micturition. Our findings demonstrate hypothyroidism impairs the bladder and, urethral functions, and reflex activation of Pcm and Bsm affecting the micturition in female rabbits. © 2018 Wiley Periodicals, Inc.

Molecular dynamics modeling and simulation of void growth in two dimensions

NASA Astrophysics Data System (ADS)

Chang, H.-J.; Segurado, J.; Rodríguez de la Fuente, O.; Pabón, B. M.; LLorca, J.

2013-10-01

The mechanisms of growth of a circular void by plastic deformation were studied by means of molecular dynamics in two dimensions (2D). While previous molecular dynamics (MD) simulations in three dimensions (3D) have been limited to small voids (up to ≈10 nm in radius), this strategy allows us to study the behavior of voids of up to 100 nm in radius. MD simulations showed that plastic deformation was triggered by the nucleation of dislocations at the atomic steps of the void surface in the whole range of void sizes studied. The yield stress, defined as stress necessary to nucleate stable dislocations, decreased with temperature, but the void growth rate was not very sensitive to this parameter. Simulations under uniaxial tension, uniaxial deformation and biaxial deformation showed that the void growth rate increased very rapidly with multiaxiality but it did not depend on the initial void radius. These results were compared with previous 3D MD and 2D dislocation dynamics simulations to establish a map of mechanisms and size effects for plastic void growth in crystalline solids.

Objective measurement of bladder sensation: use of a new patient-activated device and response to neuromodulation.

PubMed

Craggs, Michael D

2005-09-01

Detrusor overactivity is the primary objective focus of most investigations into the diagnosis and management of patients with urgency incontinence. Patients with an overactive bladder are characteristically troubled by subjective sensations of bladder fullness and urinary urgency, and frequently void at low bladder volumes attained before noticeable detrusor overactivity occurs. Bladder sensations are therefore crucial to understanding voiding patterns and symptoms, but little progress has been made in objectively describing the range of these sensations, and adequate information is lacking about their response to neuromodulation. Towards this end, a keypad 'urge score' device was designed to measure sensations during bladder filling. This patient-activated device gathers information about patient perceptions of bladder filling and the successive stages of increasing bladder sensation, without prompting or intervention by the investigator. The accuracy of the 'urge keypad' during filling cystometrography was validated in patients with urgency incontinence, and compared with data abstracted from patient voiding diaries. The device provides reliable and repeatable measures of different bladder sensations, with excellent, statistically significant consistency between bladder volumes and corresponding levels of sensation. Subsequently, it was shown that the sensation of urgency can be suppressed by neuromodulation in most patients tested; this suppression occurs with improvements in bladder capacity and voided volumes. It is therefore suggested that urodynamics with concurrent sensory evaluation may offer a more useful assessment tool for selecting those patients for therapies such as neuromodulation who present predominantly with the symptom of urgency.

The effect of alpha blockers on uroflowmetric parameters in different voiding positions

PubMed Central

Koc, Gokhan; Yilmaz, Yuksel; Un, Sitki; Akbay, Kaan; Akdeniz, Firat

2013-01-01

Introduction: We assessed the effect of different voiding positions on uroflowmetric parameters and post-void residual (PVR) urine volume in symptomatic benign prostatic hyperplasia (BPH) patients. We also evaluated the effect of alpha blockers on PVR in different voiding positions. Methods: The study was performed with 110 BPH patients over 50 years old. In total, 4 uroflowmetries were performed in all patients: 2 patients in the sitting position and 2 in the standing position. PVR was measured with transabdominal ultrasonography. Also, patients were divided into two groups according to the alpha adrenergic blocker treatment; the effect of this treatment on their uroflowmetric parameters in different positions was evaluated. Results: Maximum flow rate (Qmax) and average flow rate (Qave) were significantly higher in patients in the sitting position, but there were no differences in other uroflowmetric parameters and PVR volume (Qmax: 15.5±5.9 mL/s vs. 13.7±5.2 mL/s, Qave: 11.4±4.6 mL/s vs. 10.7± 3.9 mL/s, respectively; p < 0.05). The Qmax and Qave were significantly higher in sitting position, compared to the standing position, in both alpha adrenergic treatment and non-treated groups; again, there were no differences in other uroflowmetric parameters and PVR volume. Conclusion: Qmax and Qave values were significantly higher in the sitting position. Alpha blockers did not affect any change. PMID:23766834

Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material

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

Springer, Harry Keo

2008-07-11

The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accountedmore » for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed and executed for the purpose of validating closely-coupled 3D MSS. While the spall strength is nearly independent of specimen thickness, the fragment morphology varies widely. Detailed MSS demonstrate that the interactions between the tensile release waves are altered by specimen thickness and that these interactions are primarily responsible for fragment formation. MSS also provided insights on the regional amplification of damage, which enables the development of predictive void evolution models.« less

Sensory feedback from the urethra evokes state-dependent lower urinary tract reflexes in rat.

PubMed

Danziger, Zachary C; Grill, Warren M

2017-08-15

The lower urinary tract is regulated by reflexes responsible for maintaining continence and producing efficient voiding. It is unclear how sensory information from the bladder and urethra engages differential, state-dependent reflexes to either maintain continence or promote voiding. Using a new in vivo experimental approach, we quantified how sensory information from the bladder and urethra are integrated to switch reflex responses to urethral sensory feedback from maintaining continence to producing voiding. The results demonstrate how sensory information regulates state-dependent reflexes in the lower urinary tract and contribute to our understanding of the pathophysiology of urinary retention and incontinence where sensory feedback may engage these reflexes inappropriately. Lower urinary tract reflexes are mediated by peripheral afferents from the bladder (primarily in the pelvic nerve) and the urethra (in the pudendal and pelvic nerves) to maintain continence or initiate micturition. If fluid enters the urethra at low bladder volumes, reflexes relax the bladder and evoke external urethral sphincter (EUS) contraction (guarding reflex) to maintain continence. Conversely, urethral flow at high bladder volumes, excites the bladder (micturition reflex) and relaxes the EUS (augmenting reflex). We conducted measurements in a urethane-anaesthetized in vivo rat preparation to characterize systematically the reflexes evoked by fluid flow through the urethra. We used a novel preparation to manipulate sensory feedback from the bladder and urethra independently by controlling bladder volume and urethral flow. We found a distinct bladder volume threshold (74% of bladder capacity) above which flow-evoked bladder contractions were 252% larger and evoked phasic EUS activation 2.6 times as often as responses below threshold, clearly demonstrating a discrete transition between continence (guarding) and micturition (augmenting) reflexes. Below this threshold urethral flow evoked tonic EUS activity, indicative of the guarding reflex, that was proportional to the urethral flow rate. These results demonstrate the complementary roles of sensory feedback from the bladder and urethra in regulating reflexes in the lower urinary tract that depend on the state of the bladder. Understanding the neural control of functional reflexes and how they are mediated by sensory information in the bladder and urethra will open new opportunities, especially in neuromodulation, to treat pathologies of the lower urinary tract. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

High voltage capability electrical coils insulated with materials containing SF.sub.6 gas

DOEpatents

Lanoue, Thomas J.; Zeise, Clarence L.; Wagenaar, Loren; Westervelt, Dean C.

1988-01-01

A coil is made having a plurality of layers of adjacent metal conductor windings subject to voltage stress, where the windings have insulation therebetween containing a small number of minute disposed throughout its cross-section, where the voids are voids filled with SF.sub.6 gas to substitute for air or other gaseous materials in from about 60% to about 95% of the cross-sectional void volume in the insulation, thus incorporating an amount of SF.sub.6 gas in the cross-section of the insulation effective to substantially increase corona inception voltages.

Evidence of bladder oversensitivity in the absence of an infection in premenopausal women with a history of recurrent urinary tract infections.

PubMed

Arya, Lily A; Northington, Gina M; Asfaw, Tirsit; Harvie, Heidi; Malykhina, Anna

2012-07-01

Study Type - Prevalence (case control) Level of Evidence 4. What's known on the subject? and What does the study add? Urinary tract infections (UTIs) have been implicated in the aetiology of interstitial cystitis/painful bladder syndrome (IC/PBS). Prior studies have described symptoms and laboratory tests suggestive of UTI at the onset of IC/PBS as well as a significant history of childhood recurrent UTIs. However, the mechanism by which recurrent UTIs contribute to the development of IC/PBS is not clear. Our study shows that women with recurrent UTI suffer from bladder oversensitivity. Our findings have useful clinical implications. Women with bladder oversensitivity complain of urinary frequency which is often misdiagnosed as an infection and treated with unnecessary antibiotics. Additionally, there are no effective therapies for bladder oversensitivity. Therefore, women with recurrent UTI should undergo prompt evaluation and treatment of episodes of infection to prevent the development of bladder oversensitivity. Our findings also provide a possible mechanism for the development of IC/PBS. Whether women with recurrent UTI are at increased risk for developing IC/PBS in the future will need to be confirmed in future studies. • To compare the mean voided volume and bladder sensation during filling cystometry in women with a history of recurrent urinary tract infection (UTI) and controls. • This was a case-control study including adult women seen in the urogynaecology clinic. • The cases were 49 women with at least three documented positive urine cultures >105 colonies/mL in the previous 12 months and no active infection at the time of data collection. • Controls were 53 women with stress urinary incontinence and no history of recurrent UTI or coexistent urge urinary incontinence. • We compared bladder diary variables and filling cystometry data in the absence of an active infection. • There was no significant difference in the median age, parity and body mass index of women with a history of recurrent UTI and controls. • The median number of voids per day and median number of voids per litre of fluid intake was significantly greater in women with recurrent UTI than controls (12 vs 7 voids/day and 6 vs 4 voids/L, P= 0.005 and P= 0.004 respectively). • The median average voided volume was significantly lower in women with recurrent UTI than controls (155 vs 195 mL, P= 0.008). • On filling cystometry, median volumes of strong desire to void and maximum cystometric capacity were significantly lower in women with recurrent UTI than controls (all P < 0.05). • In the absence of an infection, premenopausal women with a history of recurrent UTI have significantly greater urinary frequency, lower average voided volume and a lower threshold of bladder sensitivity than controls. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Cholecystokinin-converting enzymes in brain.

PubMed Central

Malesci, A; Straus, E; Yalow, R S

1980-01-01

Crude extracts of porcine cerebral cortical tissue convert cholecystokinin (CCK) to its COOH-terminal fragments, the dodecapeptide (CCK-12) and the octapeptide (CCK-8). The Sephadex G-75 void volume eluate of the crude extract cleaves the arginine-isoleucine bond and effects conversion only to CCK-12; the Sephadex G-50 void volume eluate of the same extract cleaves the arginine-aspartate bond as well, so that both CCK-12 and CCK-8 are end products. Thus, there are at least two enzymes; the one involved in the conversion to CCK-12 is of larger molecular radius than the other. The Km for the cleavage of CCK at the arginine-isoleucine bond by the Sephadex G-75 void volume eluate enzyme is 1.1 X 10(-6) M; the Km for trypsin cleavage of the same bond is 4.7 x 10(-6) M. The lower Vmax for the brain enzyme (1.5 x 10(-11) mol/min per g of extract) compared with trypsin (66 x 10(-11) mol/min per g of trypsin) simply reflects the lesser degree of purify of the brain extract than of the highly purified trypsin. Images PMID:6987659

Anomalous behavior of cristobalite in helium under high pressure

NASA Astrophysics Data System (ADS)

Sato, Tomoko; Takada, Hiroto; Yagi, Takehiko; Gotou, Hirotada; Okada, Taku; Wakabayashi, Daisuke; Funamori, Nobumasa

2013-01-01

We have investigated the high-pressure behavior of cristobalite in helium by powder X-ray diffraction. Cristobalite transformed to a new phase at about 8 GPa. This phase is supposed to have a molar volume of about 30 % larger than cristobalite, suggesting the dissolution of helium atoms in its interstitial voids. On further compression, the new phase transformed to a different phase which showed an X-ray diffraction pattern similar to cristobalite X-I at about 21 GPa. On the other hand, when the new phase was decompressed, it transformed to another new phase at about 7 GPa, which is also supposed to have a molar volume of about 25 % larger than cristobalite. On further decompression, the second new phase transformed to cristobalite II at about 2 GPa. In contrast to cristobalite, quartz did not show anomalous behavior in helium. The behavior of cristobalite in helium was also consistent with that in other mediums up to about 8 GPa, where the volume of cristobalite became close to that of quartz. These results suggest that dissolution of helium may be controlled not only by the density (amount of voids) but also by the network structure of SiO4 tetrahedra (topology of voids).

Experimental investigation of defect criticality in FRP laminate composites

NASA Astrophysics Data System (ADS)

Joyce, Peter James

1999-11-01

This work examines the defect criticality of fiber reinforced polymer Composites. The objective is to determine the sensitivity of the finished composite to various process-induced defects. This work focuses on two different classes of process-induced defects; (1) fiber waviness in high performance carbon-fiber reinforced unidirectional composites and (2) void volume in low cost glass-fabric reinforced composites. The role of fiber waviness in the compressive response of unidirectional composites has been studied by a number of other investigators. Because of difficulties associated with producing real composites with varying levels of fiber waviness, most experimental studies of fiber waviness have evaluated composites with artificially induced fiber waviness. Furthermore, most experimental studies have been concentrated on the effects of out-of-plane fiber waviness. The objective of this work is to evaluate the effects of in-plane fiber waviness naturally occurring in autoclave consolidated thermoplastic laminates. The first phase of this project involved the development of a simple technique for measuring the resulting fiber waviness levels. An experimental investigation of the compression strength reduction in composites with in-plane fiber waviness followed. The experimental program included carbon-fiber reinforced thermoplastic composites manufactured from prepreg tape by hand layup, and carbon-fiber and glass-fiber reinforced composites manufactured from an experimental powder towpreg by filament winding and autoclave consolidation. The compression specimens exhibited kink band failure in the prepreg composite and varying amounts of longitudinal splitting and kink banding in the towpreg composites. The compression test results demonstrated the same trend as predicted by microbudding theory but the overall quantitative correlation was poor. The second thrust of this research evaluated void effects in resin transfer molded composites. Much of the existing literature in this area has focused on composites with unidirectional fiber reinforcement. In this program, the influence of void volume on the mechanical behavior of RTM composites with plain weave reinforcement was investigated. The experimental program demonstrated that the effects of void volume are negligible in terms of the fiber dominated properties. Interlaminar shear strength tests on the other hand demonstrated a linear dependence on void volume in the range tested.

An investigation of the plastic fracture of AISI 4340 and 18 nickel - 200 grade maraging steels

NASA Technical Reports Server (NTRS)

Cox, T. B.; Low, J. R., Jr.

1974-01-01

The mechanisms of plastic fracture (dimpled rupture) in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched and tempered AISI 4340 steels have been studied. Plastic fracture takes place in the maraging alloys through void initiation by fracture of titanium carbo-nitride inclusions and the growth of these voids until impingement results in coalescence and final fracture. The fracture of AISI 4340 steel at a yield strength of 200 ksi occurs by nucleation and subsequent growth of voids formed by fracture of the interface between manganese sulfide inclusions and the matrix. The growth of these inclusion-nucleated voids is interrupted long before coalescence by impingement, by the formation of void sheets which connect neighboring sulfide-nucleated voids.

Emergence of cracks by mass transport in elastic crystals stressed at high temperatures

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

Sun, B.; Suo, Z.; Evans, A.G.

1995-12-31

Single crystals are used under high temperature and high stresses in hostile environments (usually gases). A void produced in the fabrication process can change shape and volume, as atoms migrate under various thermodynamic forces. A small void under low stress remains rounded in shape, but a large void under high stress evolves to a crack. The material fractures catastrophically when the crack becomes sufficiently large. In this article three kinetic processes are analyzed: diffusion along the void surface, diffusion in a low melting point second phase inside the void, and surface reaction with the gases. An approximate evolution path ismore » simulated, with the void evolving as a sequence of spheroids, from a sphere to a penny-shaped crack. The free energy is calculated as a functional of void shape, from which the instability conditions are determined. The evolution rate is calculated by using variational principles derived from the valance of the reduction in the free energy and the dissipation is the kinetic processes. Crystalline anisotropy and surface heterogeneity can be readily incorporated in this energetic framework. Comparisons are made with experimental strength date for sapphire fibers measured at various strain rates.« less

Monoclinic tridymite in clast-rich impact melt rock from the Chesapeake Bay impact structure

USGS Publications Warehouse

Jackson, John C.; Horton, J. Wright; Chou, I-Ming; Belkin, Harvey E.

2011-01-01

X-ray diffraction and Raman spectroscopy confirm a rare terrestrial occurrence of monoclinic tridymite in clast-rich impact melt rock from the Eyreville B drill core in the Chesapeake Bay impact structure. The monoclinic tridymite occurs with quartz paramorphs after tridymite and K-feldspar in a microcrystalline groundmass of devitrified glass and Fe-rich smectite. Electron-microprobe analyses revealed that the tridymite and quartz paramorphs after tridymite contain different amounts of chemical impurities. Inspection by SEM showed that the tridymite crystal surfaces are smooth, whereas the quartz paramorphs contain irregular tabular voids. These voids may represent microporosity formed by volume decrease in the presence of fluid during transformation from tridymite to quartz, or skeletal growth in the original tridymite. Cristobalite locally rims spherulites within the same drill core interval. The occurrences of tridymite and cristobalite appear to be restricted to the thickest clast-rich impact melt body in the core at 1402.02–1407.49 m depth. Their formation and preservation in an alkali-rich, high-silica melt rock suggest initially high temperatures followed by rapid cooling.

Out-of-Autoclave Cure Composites

NASA Technical Reports Server (NTRS)

Hayes, Brian S.

2015-01-01

As the size of aerospace composite parts exceeds that of even the largest autoclaves, the development of new out-of-autoclave processes and materials is necessary to ensure quality and performance. Many out-of-autoclave prepreg systems can produce high-quality composites initially; however, due to long layup times, the resin advancement commonly causes high void content and variations in fiber volume. Applied Poleramic, Inc. (API), developed an aerospace-grade benzoxazine matrix composite prepreg material that offers more than a year out-time at ambient conditions and provides exceptionally low void content when out-of-autoclave cured. When compared with aerospace epoxy prepreg systems, API's innovation offers significant improvements in terms of out-time at ambient temperature and the corresponding tack retention. The carbon fiber composites developed with the optimized matrix technology have significantly better mechanical performance in terms of hot-wet retention and compression when compared with aerospace epoxy matrices. These composites also offer an excellent overall balance of properties. This matrix system imparts very low cure shrinkage, low coefficient of thermal expansion, and low density when compared with most aerospace epoxy prepreg materials.

The effectiveness of transcutaneous electrical neural stimulation therapy in patients with urinary incontinence resistant to initial medical treatment or biofeedback.

PubMed

Tugtepe, H; Thomas, D T; Ergun, R; Kalyoncu, A; Kaynak, A; Kastarli, C; Dagli, T E

2015-06-01

While there are many options for children with treatment refractory urinary incontinence, there is no single accepted method. This study's aim was to prospectively evaluate the effect of transcutaneous electrical nerve stimulation in children with urinary incontinence resistant to standard medical, urological therapy and/or biofeedback. This study was performed at a university hospital. For inclusion, patients >5 years of age first underwent evaluation with urinary ultrasonography, uroflow-electromyogram and voiding diaries. Treatment with biofeedback, alpha adrenergic blockers, anticholinergics and/or urotherapy was commenced according to uroflow-EMG and voiding diary findings. Patients with partial or no response to this standard therapy were then included in this study, performed between April 2012 and February 2014. Patients with anatomical or neurological causes for urinary incontinence were excluded. TENS was performed on S3 dermatome, every day for 3 months. Each session lasted 20 min with a frequency of 10 Hz and generated pulse of 350 μs. Intensity was determined by the child's sensitivity threshold. Medical treatment and urological therapy was continued during TENS. Uroflow parameters (voiding volume as percentage of expected bladder capacity, Qmax, Qave, flow and voiding time, postvoiding residual urine) and urinary system symptoms (presence of urinary tract infection, frequency, urge incontinence, fractionated voiding and constipation) were compared immediately before commencement and immediately after the completion of 3 months of TENS. Twenty-seven patients were included in this study (4 males, 23 females). Patients' average age was 7.2 years, 11 had overactive bladder and 16 had dysfunctional voiding. Comparison of urinary system symptoms and uroflow parameters before and after TENS are shown in Table. After 3 months of TENS; a statistically significant decrease was observed in the number of patients with frequency, urge incontinence, urinary tract infections and constipation. There was a decrease in the number of patients with fractionated voiding, although this change was not statistically significant. Similarly, for uroflow-EMG parameters; bladder capacity, Qmax, Qave and flow time increased while voiding time and PVR decreased. Changes seen in bladder capacity, Qmax and PVR were statically significant, while other changes were not. Patients' response rates after 3 months of TENS were; complete response in 70.4%, partial response in 22.2% and no response in 7.4%. This study has shown that transcutaneous electrical nerve stimulation is a promising treatment option for standard-treatment refractory children with urinary incontinence. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

“U-Method” TVT-Secur Slings: Are they obstructive?

PubMed Central

Richard, Patrick; Gagnon, Louis-Olivier; Tu, Le Mai

2012-01-01

Introduction: The TVT-Secur, a single incision sling, was introduced in 2006. It is implanted using either the “hammock” or the “U-method” technique. With the latter, the sling is tightened to create a “pillowing effect” on the urethra until a negative stress test is obtained. Short-term results seem promising. However, no study has ever reported on the voiding pattern 12 months after its implantation. Our objective was to assess whether the “U-method” technique creates an obstructive voiding pattern on pressure-flow study (PFS) 12 months after the surgery. Methods: In this retrospective study, we reviewed the charts of 33 women who underwent the “U-method” TVT-Secur. Patients were evaluated before and 12 months postoperatively with regard to different urodynamic studies (UDS). The incontinence status was also assessed 12 months after surgery. Results: At 12 months after the operation, 12.5% (4/32) of the patients reported an improvement of their stress urinary incontinence, while 78.1% (25/32) reported being cured from it. The objective cure rate was 63% (19/30). One patient had a suspected bladder outlet obstruction (BOO) based on PFS. Maximal flow rate (Qmax) was significantly lower 12 months after surgery (26.0 mL/s [range: 19.0–36.5] vs. 21.5 mL/s [range: 16.0–32.3]). However, median voided volume was lower on the postoperative uroflowmetry (446 mL [range: 348–605] vs. 320 mL [range: 243–502]). Furthermore, none of the patients complained of voiding symptoms after surgery. Conclusions: Although one patient had findings compatible with BOO, none complained of voiding symptoms. TVT-Secur may result in a lower Qmax. However, this finding may be due to a lower voiding volume on the postoperative UDS. PMID:22511425

The evolution of voids in the adhesion approximation

NASA Astrophysics Data System (ADS)

Sahni, Varun; Sathyaprakah, B. S.; Shandarin, Sergei F.

1994-08-01

We apply the adhesion approximation to study the formation and evolution of voids in the universe. Our simulations-carried out using 1283 particles in a cubical box with side 128 Mpc-indicate that the void spectrum evolves with time and that the mean void size in the standard Cosmic Background Explorer Satellite (COBE)-normalized cold dark matter (CDM) model with H50 = 1 scals approximately as bar D(z) = bar Dzero/(1+2)1/2, where bar Dzero approximately = 10.5 Mpc. Interestingly, we find a strong correlation between the sizes of voids and the value of the primordial gravitational potential at void centers. This observation could in principle, pave the way toward reconstructing the form of the primordial potential from a knowledge of the observed void spectrum. Studying the void spectrum at different cosmological epochs, for spectra with a built in k-space cutoff we find that the number of voids in a representative volume evolves with time. The mean number of voids first increases until a maximum value is reached (indicating that the formation of cellular structure is complete), and then begins to decrease as clumps and filaments erge leading to hierarchical clustering and the subsequent elimination of small voids. The cosmological epoch characterizing the completion of cellular structure occurs when the length scale going nonlinear approaches the mean distance between peaks of the gravitaional potential. A central result of this paper is that voids can be populated by substructure such as mini-sheets and filaments, which run through voids. The number of such mini-pancakes that pass through a given void can be measured by the genus characteristic of an individual void which is an indicator of the topology of a given void in intial (Lagrangian) space. Large voids have on an average a larger measure than smaller voids indicating more substructure within larger voids relative to smaller ones. We find that the topology of individual voids is strongly epoch dependent, with void topologies generally simplifying with time. This means that as voids grow older they become progressively more empty and have less structure within them. We evaluate the genus measure both for individual voids as well as for the entire ensemble of voids predicted by CDM model. As a result we find that the topology of voids when taken together with the void spectrum is a very useful statistical indicator of the evolution of the structure of the universe on large scales.

The evolution of voids in the adhesion approximation

NASA Technical Reports Server (NTRS)

Sahni, Varun; Sathyaprakah, B. S.; Shandarin, Sergei F.

1994-01-01

We apply the adhesion approximation to study the formation and evolution of voids in the universe. Our simulations-carried out using 128(exp 3) particles in a cubical box with side 128 Mpc-indicate that the void spectrum evolves with time and that the mean void size in the standard Cosmic Background Explorer Satellite (COBE)-normalized cold dark matter (CDM) model with H(sub 50) = 1 scals approximately as bar D(z) = bar D(sub zero)/(1+2)(exp 1/2), where bar D(sub zero) approximately = 10.5 Mpc. Interestingly, we find a strong correlation between the sizes of voids and the value of the primordial gravitational potential at void centers. This observation could in principle, pave the way toward reconstructing the form of the primordialpotential from a knowledge of the observed void spectrum. Studying the void spectrum at different cosmological epochs, for spectra with a built in k-space cutoff we find that the number of voids in a representative volume evolves with time. The mean number of voids first increases until a maximum value is reached (indicating that the formation of cellular structure is complete), and then begins to decrease as clumps and filaments erge leading to hierarchical clustering and the subsequent elimination of small voids. The cosmological epoch characterizing the completion of cellular structure occurs when the length scale going nonlinear approaches the mean distance between peaks of the gravitaional potential. A central result of this paper is that voids can be populated by substructure such as mini-sheets and filaments, which run through voids. The number of such mini-pancakes that pass through a given void can be measured by the genus characteristic of an individual void which is an indicator of the topology of a given void in intial (Lagrangian) space. Large voids have on an average a larger measure than smaller voids indicating more substructure within larger voids relative to smaller ones. We find that the topology of individual voids is strongly epoch dependent, with void topologies generally simplifying with time. This means that as voids grow older they become progressively more empty and have less structure within them. We evaluate the genus measure both for individual voids as well as for the entire ensemble of voids predicted by CDM model. As a result we find that the topology of voids when taken together with the void spectrum is a very useful statistical indicator of the evolution of the structure of the universe on large scales.

Presence of Voids after Continuous Wave of Condensation and Single-cone Obturation in Mandibular Molars: A Micro-computed Tomography Analysis.

PubMed

Iglecias, Elaine Faga; Freire, Laila Gonzales; de Miranda Candeiro, George Táccio; Dos Santos, Marcelo; Antoniazzi, João Humberto; Gavini, Giulio

2017-04-01

The objective of this study was to assess the presence of voids in mesial root canals of mandibular molar teeth obturated by using the single-cone (SC) and continuous wave of condensation (CWC) obturation techniques, and results were analyzed by using micro-computed tomography. Twenty-four mandibular molars with fully developed roots and mesial root curvature ranging from 25° to 35° were instrumented by using Reciproc R25 files, and then they were obturated by using the SC and CWC techniques. Specimens were scanned before and after obturation for micro-computed tomography analysis (voxel size, 17.42 μm). After volumetric analysis and tridimensional reconstruction of the root canals, data were analyzed by using analysis of variance and the Tukey test. No significant differences were observed between the 2 techniques in terms of total percentage volume of voids: CWC = 3.91% ± 0.72%; SC = 6.52% ± 1.16% (P > .05). Only in the cervical third, CWC showed a significantly lower percentage of voids when compared with SC, namely 2.86% ± 0.94% vs 8.00% ± 1.86%, respectively (P < .05). The percentage volume of voids was similar in the 2 groups and was influenced by the obturation technique only in the cervical third. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Relationship between voided volume and the urge to void among patients with lower urinary tract symptoms.

PubMed

Blaivas, Jerry G; Tsui, Johnson F; Amirian, Michael; Ranasinghe, Buddima; Weiss, Jeffrey P; Haukka, Jari; Tikkinen, Kari A O

2014-12-01

The aim of this study was to explore the relationship between voided volume (VV) and urge to void among patients with lower urinary tract symptoms. Consecutive adult patients (aged 23-90 years) were enrolled, and completed a 24 h bladder diary and the Urgency Perception Scale (UPS). Patients were categorized as urgency or non-urgency based on the Overactive Bladder Symptom Score. The relationship between UPS and VV (based on the bladder diary) was analyzed by Spearman's rho and proportional odds model. In total, 1265 micturitions were evaluated in 117 individuals (41 men, 76 women; 56 individuals in the urgency and 61 in the non-urgency group). The mean (± SD) VV and UPS were 192 ± 127 ml and 2.4 ± 1.2 ml in the urgency group and 173 ± 124 ml and 1.7 ± 1.1 ml in the non-urgency group, respectively. Spearman's rho (between UPS and VV) was 0.21 [95% confidence interval (CI) 0.13-029, p < 0.001] for the urgency group, 0.32 (95% CI 0.25-0.39, p < 0.001) for the non-urgency group, and 0.28 (95% CI 0.23-0.33, p < 0.001) for the total cohort. Urgency patients had higher UPS [odds ratio (OR) 3.1, 95% CI 2.5-3.8]. Overall, each additional 50 ml VV increased the odds of having a higher UPS with OR 1.2 (95% CI 1.2-1.3). The relationship between VV and UPS score was similar in both groups (p = 0.548 for interaction). Although urgency patients void with a higher UPS score, among both urgency and non-urgency patients there is only a weak correlation between VV and the urge to void. This suggests that there are factors other than VV that cause the urge to void.

3D Simulations of Void collapse in Energetic Materials

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Udaykumar, H. S.

2017-06-01

Voids present in the microstructure of heterogeneous energetic materials effect the sensitivity towards ignition. It is established that the morphology of voids can play a significant role in sensitivity enhancement of energetic materials. Depending on the void shape, sensitivity can be either increased or decreased under given loading conditions. In the past, effects of different void shapes i.e. triangular, ellipse, cylindrical etc. on the sensitivity of energetic materials have been analyzed. However, most of these studies are performed in 2D and are limited under the plain strain assumption. Axisymmetric studies have also been performed in the past to incorporate the 3D effects, however axisymmetric modeling is limited to only certain geometries i.e. sphere. This work analyzes the effects of various void shapes in three dimensions on the ignition behavior of HMX. Various void shapes are analyzed including spherical, prolate and oblate speheroid oriented at different orientations, etc. Three dimensional void collapse simulations are performed on a single void to quantify the effects void morphology on initiation. A Cartesian grid based Eulerian solver SCIMITAR3D is used to perform the void collapse simulations. Various aspects of void morphology i.e. size, thickness of voids, elongation, orientation etc. are considered to obtain a comprehensive analysis. Also, 2D plane strain calculations are compared with the three dimensional analysis to evaluate the salient differences between 2D and 3D modeling.

[Midline Cyst of the Prostate with Increased Urinary Frequency and Urgency : A Case Report].

PubMed

Nakano, Kosuke; Kiuchi, Hiroshi; Miyagawa, Yasushi; Tsujimura, Akira; Nonomura, Norio

2018-02-01

A 40-year-old man presented to our institution with a few-month history of increased urinary frequency, urgency and voiding difficulty. He had severe lower urinary tract symptoms with an International Prostate Symptom Score of 28 and quality of life score of 6. The mean urinary frequency and voided volume was 20 times per day and 150 ml, respectively. Abdominal ultrasonography and pelvic magnetic resonance imaging revealed the prostate measuring 15 cm3 with a 3 cm midline cyst which compressed the posterior of the bladder wall. A subsequent examination indicated that his lower urinary tract symptoms could be attributed to the cystic mass which mainly affected his storage symptoms. The patient underwent transurethral unroofing of the prostate cyst. Immediately after the surgery, his storage symptoms were improved greatly. The voiding volume was increased to 250 ml, and the frequency of urination was decreased to 8 times. No recurrent symptoms were found for seven months after the surgery.

Twenty-Four-Hour Voiding Diaries Versus 3-Day Voiding Diaries: A Clinical Comparison.

PubMed

Elmer, Caroline; Murphy, Amber; Elliott, John O; Book, Nicole M

This study aimed to determine if 24-hour versus 3-day voiding diary affects medical decision making for women with urinary incontinence. A retrospective chart review was conducted of patients presenting to the OhioHealth Urogynecology Physician group for urinary incontinence from 2009 to 2011. Practice protocol includes patient completion of a 3-day voiding diary before their appointment. Diagnostic and treatment plans were extracted based on the initial patient encounter and 3-day voiding diary. A chart review was then completed with the first 24 hours of the same diaries, principal history, and physical examination data compiled into a separate chart. These charts were then reevaluated by the same physician who initially provided care to the patient but were blinded to their previous orders, impressions, and plans. New plans were then created based on the 24-hour diaries and compared with the original plans. One hundred eighty-six charts were reviewed. There was good agreement between 24-hour and 3-day diaries in recommendations for first-line behavioral modifications (Κ > 0.6) and moderate agreement between diaries in initiation of medical therapy or trial of incontinence pessary (Κ > 0.4). However, 24-hour diaries resulted in a statistically significant increase in invasive diagnostic tests (P < 0.019) and other treatment recommendations when compared with 3-day diaries. Use of 24-hour diaries may result in increased testing when compared with 3-day diaries. It may be prudent to postpone invasive testing in those patients who initially are noncompliant with a longer diary until a more complete history can be obtained.

Modeling of hot-mix asphalt compaction : a thermodynamics-based compressible viscoelastic model

DOT National Transportation Integrated Search

2010-12-01

Compaction is the process of reducing the volume of hot-mix asphalt (HMA) by the application of external forces. As a result of compaction, the volume of air voids decreases, aggregate interlock increases, and interparticle friction increases. The qu...

Recurring priapism may be a symptom of voiding dysfunction – case report and literature review

PubMed Central

de Jesus, Lisieux Eyer; Teixeira, Leonardo; Bertelli, André

2016-01-01

ABSTRACT Recurring priapism is rare in pre-pubertal children and may be attributed to multiple causes. We propose that voiding dysfunction (VD) may also justify this symptom and detail a clinical case of recurring stuttering priapism associated to overactive bladder that completely resolved after usage of anticholinergics and urotherapy. Sacral parasympathetic activity is responsible for detrusor contraction and for spontaneous erections and a relationship between erections and bladder status has been proved in healthy subjects (morning erections) and models of medullar trauma. High bladder pressures and/or volumes, voiding incoordination and posterior urethritis can potentially trigger reflex erections. PMID:27256196

Runoff initiation from falling raindrops - comparison of smooth impervious surface and asphalt pavements. Effects of surface inclination and texture.

NASA Astrophysics Data System (ADS)

Nezlobin, David; Pariente, Sarah; Lavee, Hanoch; Sachs, Eyal; Levenberg, Eyal

2017-04-01

The processes of runoff initiation on smooth impervious surfaces and various asphalt pavements are investigated in laboratory rain simulator experiments and outdoor sprinkling tests. Visual and FLIR observations indicate that runoff initiation is associated with coalescence of drop clusters on the surface and complex changes in micro-connectivity. Depending on surface inclination, several morphological regimes of flow initiation have been observed. In the case of very small inclination the runoff initiation is governed by critical merging of drop clusters on the surface and develops in broad flows (very abrupt, but delayed). For larger inclinations, the runoff occurs in rivulets or strongly directed flow threads. On asphalt pavements the runoff initiation is also strongly affected by pavement SVF (Surface Void Fraction), texture and even by the asphalt hydrophobicity. A simplified bi-level model of the pavement surface may explain principal differences in the runoff initiation on asphalts with small, intermediate and large SVF values. For small SVF (standard fresh asphalts) the runoff develops on the upper surface level, and filling of the surface voids is not always required (especially for the large inclinations). For intermediate SVF (considerably deteriorated asphalts) the runoff develops as well on the upper surface level, but only after considerable filling of the surface voids. Finally, on severely deteriorated asphalts (very large SVFs) the runoff develops on the "bottom" level of asphalt surface, after only partial filling of the surface voids. Other factors, such as drops splash and splitting, also affect the process of runoff initiation and explain rather considerable differences (sometimes of 2-3 mm rain depth) in the runoff thresholds on various non-porous asphalt pavements. Similar phenomena can be probably observed on certain types of rock outcrops.

Improvement effect on the depth-dose distribution by CSF drainage and air infusion of a tumour-removed cavity in boron neutron capture therapy for malignant brain tumours

NASA Astrophysics Data System (ADS)

Sakurai, Yoshinori; Ono, Koji; Miyatake, Shin-ichi; Maruhashi, Akira

2006-03-01

Boron neutron capture therapy (BNCT) without craniotomy for malignant brain tumours was started using an epi-thermal neutron beam at the Kyoto University Reactor in June 2002. We have tried some techniques to overcome the treatable-depth limit in BNCT. One of the effective techniques is void formation utilizing a tumour-removed cavity. The tumorous part is removed by craniotomy about 1 week before a BNCT treatment in our protocol. Just before the BNCT irradiation, the cerebro-spinal fluid (CSF) in the tumour-removed cavity is drained out, air is infused to the cavity and then the void is made. This void improves the neutron penetration, and the thermal neutron flux at depth increases. The phantom experiments and survey simulations modelling the CSF drainage and air infusion of the tumour-removed cavity were performed for the size and shape of the void. The advantage of the CSF drainage and air infusion is confirmed for the improvement in the depth-dose distribution. From the parametric surveys, it was confirmed that the cavity volume had good correlation with the improvement effect, and the larger effect was expected as the cavity volume was larger.

Improvement effect on the depth-dose distribution by CSF drainage and air infusion of a tumour-removed cavity in boron neutron capture therapy for malignant brain tumours.

PubMed

Sakurai, Yoshinori; Ono, Koji; Miyatake, Shin-Ichi; Maruhashi, Akira

2006-03-07

Boron neutron capture therapy (BNCT) without craniotomy for malignant brain tumours was started using an epi-thermal neutron beam at the Kyoto University Reactor in June 2002. We have tried some techniques to overcome the treatable-depth limit in BNCT. One of the effective techniques is void formation utilizing a tumour-removed cavity. The tumorous part is removed by craniotomy about 1 week before a BNCT treatment in our protocol. Just before the BNCT irradiation, the cerebro-spinal fluid (CSF) in the tumour-removed cavity is drained out, air is infused to the cavity and then the void is made. This void improves the neutron penetration, and the thermal neutron flux at depth increases. The phantom experiments and survey simulations modelling the CSF drainage and air infusion of the tumour-removed cavity were performed for the size and shape of the void. The advantage of the CSF drainage and air infusion is confirmed for the improvement in the depth-dose distribution. From the parametric surveys, it was confirmed that the cavity volume had good correlation with the improvement effect, and the larger effect was expected as the cavity volume was larger.

Bird's nest-like nanographene shell encapsulated Si nanoparticles - Their structural and Li anode properties

NASA Astrophysics Data System (ADS)

Li, Beibei; Jiang, Yizhe; Jiang, Fan; Cao, Daxian; Wang, Hongkang; Niu, Chunming

2017-02-01

Bird's nest-like nanographene shell (NGS) encapsulated Si@SiO2 nanoparticles have been prepared by a simple chemical vapor deposition (CVD) method. The shell is comprised of a conformed coating with 4-10 layers of the nanographene, and nanographene spikes with the same thickness grown on the coating surface. The high crystallinity of the shell is demonstrated by XRD, HRTEM and Raman characterization. After SiO2 has been removed, distinctive void space is created between Si core and nested NGS. Statistical estimation from TEM images of 50 Si@void@NGS particles shows that the volume of void space is about 2.82 times of that of Si nanoparticle, sufficient to accommodate volume change from Si to Li15Si4. Evaluation of Si@void@NGS for Li ion anode reveals a specific capacity of 2634 mAh g-1 at a current density of 0.2 A g-1, and an excellent rate and cycling performance. The capacity decreases by 5.2%-2497 mAh g-1 after cycling at current densities of 0.5, 1, 2, 5 10, 20 A g-1. The excellent performance can be attributed to high conductivity and high stability of the shell, which remains intact after repeated cycling.

Evaluation of a mobile voiding diary for pediatric patients with voiding dysfunction: a prospective comparative study.

PubMed

Johnson, Emilie K; Estrada, Carlos R; Johnson, Kathryn L; Nguyen, Hiep T; Rosoklija, Ilina; Nelson, Caleb P

2014-09-01

One potential strategy for improving voiding diary completion rates and data quality is use of a mobile electronic format. We evaluated the acceptability and feasibility of mobile voiding diaries for patients with nonneurogenic lower urinary tract dysfunction, and compared mobile and paper voiding diaries. We prospectively enrolled children presenting with daytime symptoms of lower urinary tract dysfunction between July 2012 and April 2013. We enrolled an initial cohort of patients who were provided a paper voiding diary and a subsequent cohort who were provided a mobile voiding diary. We conducted in person interviews and assessed completion rates and quality, comparing paper and mobile voiding diary groups. We enrolled 45 patients who received a paper voiding diary and 38 who received a mobile voiding diary. Completion rates were 78% for paper voiding diaries and 61% for mobile voiding diaries (p = 0.10). Data quality measures for patients completing paper vs mobile voiding diaries revealed a larger proportion (63% vs 52%) providing a full 5 days of data and a smaller proportion (20% vs 65%) with data gaps. However, the paper voiding diary also demonstrated a lower proportion (80% vs 100%) that was completely legible and a lower proportion (40% vs 65%) with completely prospective data entry. The use of a mobile voiding diary was acceptable and feasible for our patients with lower urinary tract dysfunction, although completion rates were somewhat lower compared to paper voiding diaries. Data quality was not clearly better for either version. The mobile voiding diary format may offer data quality advantages for select groups but it did not display significant superiority when provided universally. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Inverted initial conditions: Exploring the growth of cosmic structure and voids

DOE PAGES

Pontzen, Andrew; Roth, Nina; Peiris, Hiranya V.; ...

2016-05-18

We introduce and explore “paired” cosmological simulations. A pair consists of an A and B simulation with initial conditions related by the inversion δ A(x,t initial) = –δ B(x,t initial) (underdensities substituted for overdensities and vice versa). We argue that the technique is valuable for improving our understanding of cosmic structure formation. The A and B fields are by definition equally likely draws from ΛCDM initial conditions, and in the linear regime evolve identically up to the overall sign. As nonlinear evolution takes hold, a region that collapses to form a halo in simulation A will tend to expand tomore » create a void in simulation B. Applications include (i) contrasting the growth of A-halos and B-voids to test excursion-set theories of structure formation, (ii) cross-correlating the density field of the A and B universes as a novel test for perturbation theory, and (iii) canceling error terms by averaging power spectra between the two boxes. Furthermore, generalizations of the method to more elaborate field transformations are suggested.« less

Efficacy and Safety of Initial Combination Treatment of an Alpha Blocker with an Anticholinergic Medication in Benign Prostatic Hyperplasia Patients with Lower Urinary Tract Symptoms: Updated Meta-Analysis.

PubMed

Kim, Hyun Jung; Sun, Hwa Yeon; Choi, Hoon; Park, Jae Young; Bae, Jae Hyun; Doo, Seung Whan; Yang, Won Jae; Song, Yun Seob; Ko, Young Myoung; Kim, Jae Heon

2017-01-01

There is still controversy as to whether initial combination treatment is superior to serial addition of anticholinergics after maintenance or induction of alpha blockers in benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS). The objective of this study was to determine the benefits and safety of initial combination treatment of an alpha blocker with anticholinergic medication in BPH/LUTS through a systematic review and meta-analysis. We conducted a meta-analysis of improvement in LUTS using International Prostate Symptom Score (IPSS), maximal urinary flow rate (Qmax), post-voided residual volume (PVR), and quality of life (QoL). In total, 16 studies were included in our analysis, with a total sample size of 3,548 subjects (2,195 experimental subjects and 1,353 controls). The mean change in total IPSS improvement from baseline in the combination group versus the alpha blocker monotherapy group was -0.03 (95% CI: -0.14-0.08). The pooled overall SMD change of storage IPSS improvement from baseline was -0.28 (95% CI: -0.40 - -0.17). The pooled overall SMD changes of QoL, Qmax, and PVR were -0.29 (95% CI: -0.50 - -0.07), 0.00 (95% CI: -0.08-0.08), and 0.56 (95% CI: 0.23-0.89), respectively. There was no significant difference in the number of acute urinary retention (AUR) events or PVR. Initial combination treatment of an alpha blocker with anticholinergic medication is efficacious for in BPH/ LUTS with improved measures such as storage symptoms and QoL without causing significant deterioration of voiding function.

Efficacy and Safety of Initial Combination Treatment of an Alpha Blocker with an Anticholinergic Medication in Benign Prostatic Hyperplasia Patients with Lower Urinary Tract Symptoms: Updated Meta-Analysis

PubMed Central

Kim, Hyun Jung; Sun, Hwa Yeon; Choi, Hoon; Park, Jae Young; Bae, Jae Hyun; Doo, Seung Whan; Yang, Won Jae; Song, Yun Seob; Ko, Young Myoung

2017-01-01

Background There is still controversy as to whether initial combination treatment is superior to serial addition of anticholinergics after maintenance or induction of alpha blockers in benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS) Objective The objective of this study was to determine the benefits and safety of initial combination treatment of an alpha blocker with anticholinergic medication in BPH/LUTS through a systematic review and meta-analysis. Methods We conducted a meta-analysis of improvement in LUTS using International Prostate Symptom Score (IPSS), maximal urinary flow rate (Qmax), post-voided residual volume (PVR), and quality of life (QoL). Results In total, 16 studies were included in our analysis, with a total sample size of 3,548 subjects (2,195 experimental subjects and 1,353 controls). The mean change in total IPSS improvement from baseline in the combination group versus the alpha blocker monotherapy group was -0.03 (95% CI: -0.14–0.08). The pooled overall SMD change of storage IPSS improvement from baseline was -0.28 (95% CI: -0.40 - -0.17). The pooled overall SMD changes of QoL, Qmax, and PVR were -0.29 (95% CI: -0.50 - -0.07), 0.00 (95% CI: -0.08–0.08), and 0.56 (95% CI: 0.23–0.89), respectively. There was no significant difference in the number of acute urinary retention (AUR) events or PVR. Conclusions Initial combination treatment of an alpha blocker with anticholinergic medication is efficacious for in BPH/ LUTS with improved measures such as storage symptoms and QoL without causing significant deterioration of voiding function. PMID:28072862

Murine social stress results in long lasting voiding dysfunction.

PubMed

Butler, Stephan; Luz, Sandra; McFadden, Kile; Fesi, Joanna; Long, Christopher; Spruce, Lynn; Seeholzer, Steven; Canning, Douglas; Valentino, Rita; Zderic, Stephen

2018-01-01

Repeated exposure to social stress shifts the voiding phenotype in male mice leading to bladder wall remodeling and is associated with increased expression of the stress neuropeptide, corticotropin-releasing factor (CRF) in Barrington's nucleus neurons. In these studies, we set out to determine if the voiding phenotype could recover upon removal from the stressor. Male mice were exposed for 1h daily to an aggressor and the voiding phenotype was assessed at one month followed by randomization to three groups. One group underwent immediate sacrifice. Two groups were allowed a one month recovery from the social stress exposure with or without the addition of fluoxetine (1.2mg/ml) in their drinking water and repeat voiding patterns were measured prior to sacrifice. Social stress significantly increased bladder mass, bladder mass corrected for body weight, voided volumes, and decreased urinary frequency. The abnormal voiding phenotype persisted after a 1month recovery with no effect from the addition of fluoxetine. CRF mRNA in Barrington's nucleus was increased by social stress and remained elevated following recovery with no effect from the addition of fluoxetine. The mRNA and protein expression for the alpha 1 chains of type 1 and type III collagen was unchanged across all groups suggesting that changes in the extracellular matrix of the bladder are not responsible for the voiding phenotype. This persisting voiding dysfunction correlates with the persistent elevation of CRF mRNA expression in Barrington's nucleus. Copyright © 2017. Published by Elsevier Inc.

Effect of Preoperative Low Maximal Flow Rate on Postoperative Voiding Trials after the Midurethral Sling Procedure in Women with Stress Urinary Incontinence.

PubMed

Chae, Ji Y; Bae, Jae H; Lee, Jeong G; Park, Hong S; Moon, Du G; Oh, Mi M

2017-06-02

To evaluate the effects of preoperative low maximal flow rate (Qmax) on voiding trials after the midurethral sling (MUS) procedure in women with stress urinary incontinence (SUI). One hundred and sixty-eight women who underwent MUS procedure were enrolled. Preoperative free uroflowmetry was performed and patients were divided by Qmax. Low Qmax was defined as a Qmax under 15 mL/sec with voided volume at least 150 mL. Surgical results, failure of voiding trial, and postoperative uroflowmetry parameters were compared between the groups. Failure of voiding trial was defined by a PVR more than 100 mL on postoperative uroflowmetry. At the discharge day, there were 42 cases showing failure of voiding trial and 33 cases requiring CIC, but only one patient showed failure of voiding trial at 12 months postoperatively. Overall, 48 patients had preoperative low Qmax. Low Qmax group showed lower Qmax in all of postoperative uroflowmetry, but there were no significant differences in the rate of postoperative voiding trial failure or CIC. The low Qmax group was then divided into two groups according to the preoperative detrusor pressure at Qmax over and under 20 cmH 2 O in pressure flow study. Comparing the two groups, no significant differences were observed in the cure rate, voiding trial failure or CIC. Our results suggest that women with preoperative low Qmax experienced no definite unfavorable voiding problem from the MUS procedure compared to those with normal voiding function. MUS procedure may be regarded as a safe and successful procedure in SUI women with low Qmax. © 2017 John Wiley & Sons Australia, Ltd.

Development of construction materials using nano-silica and aggregates recycled from construction and demolition waste.

PubMed

Mukharjee, Bibhuti Bhusan; Barai, Sudhirkumar V

2015-06-01

The present work addresses the development of novel construction materials utilising commercial grade nano-silica and recycled aggregates retrieved from construction and demolition waste. For this, experimental work has been carried out to examine the influence of nano-silica and recycled aggregates on compressive strength, modulus of elasticity, water absorption, density and volume of voids of concrete. Fully natural and recycled aggregate concrete mixes are designed by replacing cement with three levels (0.75%, 1.5% and 3%) of nano-silica. The results of the present investigation depict that improvement in early days compressive strength is achieved with the incorporation of nano-silica in addition to the restoration of reduction in compressive strength of recycled aggregate concrete mixes caused owing to the replacement of natural aggregates by recycled aggregates. Moreover, the increase in water absorption and volume of voids with a reduction of bulk density was detected with the incorporation of recycled aggregates in place of natural aggregates. However, enhancement in density and reduction in water absorption and volume of voids of recycled aggregate concrete resulted from the addition of nano-silica. In addition, the results of the study reveal that nano-silica has no significant effect on elastic modulus of concrete. © The Author(s) 2015.

An initial study of void formation during solidification of aluminum in normal and reduced-gravity

NASA Technical Reports Server (NTRS)

Chiaramonte, Francis P.; Foerster, George; Gotti, Daniel J.; Neumann, Eric S.; Johnston, J. C.; De Witt, Kenneth J.

1992-01-01

Void formation due to volumetric shrinkage during aluminum solidification was observed in real time using a radiographic viewing system in normal and reduced gravity. An end chill directional solidification furnace with water quench was developed to solidify aluminum samples during the approximately 16 seconds of reduced gravity (+/- 0.02g) achieved by flying an aircraft through a parabolic trajectory. Void formation was recorded for two cases: first a nonwetting system; and second, a wetting system where wetting occurs between the aluminum and crucible lid. The void formation in the nonwetting case is similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible. In the wetting case in reduced gravity, surface tension causes two voids to form in the top corners of the crucible, but in normal gravity only one large voids forms across the top.

Effectiveness of pelvic floor muscle training on symptoms and uroflowmetry parameters in female patients with overactive bladder.

PubMed

Kulaksizoğlu, Haluk; Akand, Murat; Çakmakçi, Evrim; Gül, Murat; Seçkin, Bedreddin

2015-01-01

To evaluate the effects of pelvic floor muscle training (PFMT) on symptoms of overactive bladder (OAB) as well as uroflowmetry parameters and functional bladder capacity. Fifty-nine female patients with OAB symptoms were included. Patients were assessed by SEAPI-QMM, uroflowmetry, and abdominal ultrasound. A specially designed PFMT program using a Pilates ball was generated for patients. The training period was 1-h sessions twice a week for 6 weeks and aerobic home exercises to be performed at home 4 or 5 times every other day. Following training, subjects were reevaluated for body mass index, SEAPI questionnaire, and uroflowmetry. Initial mean SEAPI score, mean maximum and average flow rates, and mean voided volume were 9.8 ± 7.2, 29.8 ± 16.4 mL/s, 16.3 ± 8.7 mL/s, and 211.6 ± 173.5 mL, respectively. After completion of the training program, SEAPI scores improved significantly to 3.4 ± 6.4 (P < 0.05). Maximum and average flow rate results did not show significant changes, whereas voided volume seemed to have improved in conjunction with patients' symptom scores (Pearson correlation coefficient: 0.86). According to. our results, we think that proper PFMT results in increase of functional bladder capacity as well as improvement in OAB symptoms and can be recommended as first-line therapy or in conjunction with medical therapy in severe cases.

The Effect of Drying-Wetting Cycle’s Repetition to the Characteristic of Natural and Stabilization Residual Soils Jawa Timur - Indonesia

NASA Astrophysics Data System (ADS)

Muntaha, M.

2017-11-01

Indonesia, which located in tropical region, continuously undergoes wetting and drying cycles due to the changeable seasons. An important role in activating the clay minerals on tropical residual soils is the main factor that affects the static and dynamic properties, such as: volume change, soil suction and dynamic modulus. The purpose of this paper is to evaluate the effect of drying-wetting cycles repetition on volume change, soil suction and mechanical characteristics of natural and stabilization of residual soils from Jawa Timur - Indonesia. The natural undisturbed and stabilized residual soil sample was naturally and gradually dried up with air to 25%, 50%, 75%, and 100 % of the initial water content. The wetting processes were carried out with the gradual increment water content of 25 %(wsat - wi), 50 %(wsat - wi), 75 %(wsat - wi), up to 100 %(wsat - wi). The Direct Shear test is used to measure the mechanic properties, and Whatman filter paper No. 42 is used to measure the soil suction. The drying-wetting processes were carried out for 1, 2, 4, and 6 cycles. The laboratory test results showed that, the void ratio decreased, the unit weight, cohesion and the internal friction angle were increasing due to stabilization. Drying-wetting cycle repetition reduces void ratio, negative pore-water pressure, cohesion and internal friction angle of natural and stabilized soils. Briefly, the decreased of mechanical soil properties was proven from the physical properties change observation.

Cavitation instability in bulk metallic glasses

NASA Astrophysics Data System (ADS)

Dai, L. H.; Huang, X.; Ling, Z.

2015-09-01

Recent experiments have shown that fracture surfaces of bulk metallic glasses (BMGs) usually exhibit an intriguing nanoscale corrugation like fractographic feature mediated by nanoscale void formation. We attribute the onset of this nanoscale corrugation to TTZs (tension transformation zones) mediated cavitation. In our recent study, the spall experiments of Zr-based BMG using a single-stage light gas gun were performed. To uncover the mechanisms of the spallation damage nucleation and evolution, the samples were designed to be subjected to dynamic tensile loadings of identical amplitude but with different durations by making use of the multi-stress pulse and the double-flyer techniques. It is clearly revealed that the macroscopic spall fracture in BMGs originates from the nucleation, growth and coalescence of micro-voids. Then, a microvoid nucleation model of BMGs based on free volume theory is proposed, which indicates that the nucleation of microvoids at the early stage of spallation in BMGs is resulted from diffusion and coalescence of free volume. Furthermore, a theoretical model of void growth in BMGs undergoing remote dynamic hydrostatic tension is developed. The critical condition of cavitation instability is obtained. It is found that dynamic void growth in BMGs can be well controlled by a dimensionless inertial number characterizing the competition between intrinsic and extrinsic time scales. To unveil the atomic-level mechanism of cavitation, a systematic molecular dynamics (MD) simulation of spallation behaviour of a binary metallic glass with different impact velocities was performed. It is found that micro-void nucleation is determined TTZs while the growth is controlled by shear transformation zones (STZs) at atomic scale.

CRITICAL EXPERIMENT WITH BORAX-V. Internal Superheater

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

Plumlee, K.E.; Baird, Q.L.; Stanford, G.S.

1963-11-01

A critical experiment was performed with 12 BORAX-V superheater subassemblies in a central voidable region plus 1228 to 1525 UO/sub 2/ fuel pins (3 wt% enriched) in a peripheral region. Removing water (28% of superheater volume) at room temperature decreased reactivity by 2.2%. The midplane (two- dimensional) peak-to-average power distribution in the voided superheater was approximately 1.24, mostly attributable to flux depressions within insulated fuel boxes. Cadmium ratios are also reported. The experiment was initiated to supplement computational information which might have affected plans for loading the superheater zone into the BORAX-V reactor. No changes were indicated by the experiment.more » (auth)« less

The structure of steady shock waves in porous metals

NASA Astrophysics Data System (ADS)

Czarnota, Christophe; Molinari, Alain; Mercier, Sébastien

2017-10-01

The paper aims at developing an understanding of steady shock wave propagation in a ductile metallic material containing voids. Porosity is assumed to be less than 0.3 and voids are not connected (foams are not considered). As the shock wave is traveling in the porous medium, the voids are facing a rapid collapse. During this dynamic compaction process, material particles are subjected to very high acceleration in the vicinity of voids, thus generating acceleration forces at the microscale that influence the overall response of the porous material. Analyzing how stationary shocks are influenced by these micro-inertia effects is the main goal of this work. The focus is essentially on the shock structure, ignoring oscillatory motion of pores prevailing at the tail of the shock wave. Following the constitutive framework developed by Molinari and Ravichandran (2004) for the analysis of steady shock waves in dense metals, an analytical approach of steady state propagation of plastic shocks in porous metals is proposed. The initial void size appears as a characteristic internal length that scales the overall dynamic response, thereby contributing to the structuring of the shock front. This key feature is not captured by standard damage models where the porosity stands for the single damage parameter with no contribution of the void size. The results obtained in this work provide a new insight in the fundamental understanding of shock waves in porous media. In particular, a new scaling law relating the shock width to the initial void radius is obtained when micro-inertia effects are significant.

Statistics of voids in hierarchical universes

NASA Technical Reports Server (NTRS)

Fry, J. N.

1986-01-01

As one alternative to the N-point galaxy correlation function statistics, the distribution of holes or the probability that a volume of given size and shape be empty of galaxies can be considered. The probability of voids resulting from a variety of hierarchical patterns of clustering is considered, and these are compared with the results of numerical simulations and with observations. A scaling relation required by the hierarchical pattern of higher order correlation functions is seen to be obeyed in the simulations, and the numerical results show a clear difference between neutrino models and cold-particle models; voids are more likely in neutrino universes. Observational data do not yet distinguish but are close to being able to distinguish between models.

[Effect of the night shift work on micturition patterns of nurses].

PubMed

Wang, Q; Hu, H; Liang, C; Wang, J; Xu, K X

2016-02-18

To compare the effects of rotational night shifts on the micturition patterns of female nurses. A total of 58 nurses without lower urinary tract symptoms were recruited, who worked in the Peking University People's Hospital during January and June in 2014. The nurses aged 20-43 years were divided into two groups, the night-shift group (n=28) and the non-shift group (n=30). The alcohol or coffee intaking were forbidden. In the night-shift group, nurses had worked on rotational shifts for at least 6 months. Their average age was (26.75±4.11) years. In the non-shift group, nurses took regular day-time work, whose average age was (27.80±5.60) years. A voiding diary was kept for 7 consecutive days at the end of 6 months, starting 2 days before their night duties until 4 days after completion of their night duties. For comparison, the non-shift group with regular shifts completed a 7-day voiding diary. In the 7-day recording voiding diary, the nurses were required to have the normal intake of liquid about 1 500-2 000 mL/d. The frequency volume charts of nocturia, the 8-hour interval urine production and frequency were compared between the two groups. Nocturia frequency was increased in the night-shift group [0.5 (0-2.4)] compared with the non-shift group [0 (0-2), P=0.02]. The volume of nocturia was increased in the night-shift group [125 mL (0-660 mL)] compared with the non-shift group [0 mL (0-340 mL), P<0.01]. The 8-hour interval indices showed that urine production changed with shift (P<0.01). In the consecutive 7 days, the nocturnal volume of the night-shift group increased on the day after night shift. When the night-shift nurses returned to daytime duty, the volume of urine decreased but nocturnal urine production remained high, and the frequency of nocturia also increased significantly (P<0.05). Compared with the 8-hour interval indices, the night-shift group's voiding volume [(542.35±204.66) mL] and voiding frequency (2.24±0.69) were more than those of the non-shift group at the afternoon time (from 2 pm to 10 pm). During the 8 h interval night time (from 10 pm to 6 am), the volume of nocturia in the night-shift group [(309.74±162.74) mL] was more than that in the non-shift group [(199.38±153.98) mL, P=0.01]; the frequency of nocturia in the night-shift group (1.31±0.52) was increased than that in the non-shift group (0.82±0.55, P<0.01). The rotational shifts affect the micturition patterns of nurses who go through the night shift work, which increases the volume and frequency of the nocturia.

[Effect of the night shift work on micturition patterns of nurses].

PubMed

Wang, Q; Hu, H; Liang, C; Wang, J; Xu, K X

2016-08-18

To compare the effects of rotational night shifts on the micturition patterns of female nurses. A total of 58 nurses without lower urinary tract symptoms were recruited, who worked in the Peking University People's Hospital during January and June in 2014. The nurses aged 20-43 years were divided into two groups, the night-shift group (n=28) and the non-shift group (n=30). The alcohol or coffee intaking were forbidden. In the night-shift group, nurses had worked on rotational shifts for at least 6 months. Their average age was (26.75±4.11) years. In the non-shift group, nurses took regular day-time work, whose average age was (27.80±5.60) years. A voiding diary was kept for 7 consecutive days at the end of 6 months, starting 2 days before their night duties until 4 days after completion of their night duties. For comparison, the non-shift group with regular shifts completed a 7-day voiding diary. In the 7-day recording voiding diary, the nurses were required to have the normal intake of liquid about 1 500-2 000 mL/d. The frequency volume charts of nocturia, the 8-hour interval urine production and frequency were compared between the two groups. Nocturia frequency was increased in the night-shift group [0.5 (0-2.4)] compared with the non-shift group [0 (0-2), P=0.02]. The volume of nocturia was increased in the night-shift group [125 mL (0-660 mL)] compared with the non-shift group [0 mL (0-340 mL), P<0.01]. The 8-hour interval indices showed that urine production changed with shift (P<0.01). In the consecutive 7 days, the nocturnal volume of the night-shift group increased on the day after night shift. When the night-shift nurses returned to daytime duty, the volume of urine decreased but nocturnal urine production remained high, and the frequency of nocturia also increased significantly (P<0.05). Compared with the 8-hour interval indices, the night-shift group's voiding volume [(542.35±204.66) mL] and voiding frequency (2.24±0.69) were more than those of the non-shift group at the afternoon time (from 2 pm to 10 pm). During the 8 h interval night time (from 10 pm to 6 am), the volume of nocturia in the night-shift group [(309.74±162.74) mL] was more than that in the non-shift group [(199.38±153.98) mL, P=0.01]; the frequency of nocturia in the night-shift group (1.31±0.52) was increased than that in the non-shift group (0.82±0.55, P<0.01). The rotational shifts affect the micturition patterns of nurses who go through the night shift work, which increases the volume and frequency of the nocturia.

Free uroflowmetry versus "Do-It-Yourself" uroflowmetry in the assessment of patients with lower urinary tract symptoms.

PubMed

Mombelli, Gabriella; Picozzi, Stefano; Messina, Giovanni; Truffelli, Dario; Marenghi, Carlo; Maffi, Gabriele; Carmignani, Luca

2014-10-01

We investigated the possibility that patients could carry out a urine flow assessment at home by themselves, in comfort, without expense and without the use of equipment. We compared this strategy of "Do-It-Yourself" (DIY) uroflowmetry with traditional, hospital uroflowmetry. One hundred and twenty patients were enrolled. The patients underwent conventional, free uroflowmetry in hospital. Subsequently, the patients were asked to carry out the following procedure at home: urinate into a graduated container to quantify the total voided volume and determine the flow time by measuring the duration of miction with a stopwatch or simply with the second hand of a clock. This procedure had to be performed three times without preparation. Hundred patients completed the study. The mean age of the patients analysed was 64.12 years. Their free uroflowmetry values were as follows: the mean voiding time was 44.28 s, the mean voided volume was 290.92 ml, the mean Qmax was 15.17 ml/s, the mean Qmean was 7.87 ml/s, and the mean post-void residual volume was 78.44 ml. The mean Qmean measured by the "DIY-uroflowmetry" was 8.33 ml/s, which was not statistically significantly different (P = 0.12). Assuming that pathological hospital uroflowmetry values are equivalent to a DIY-Qmean ≤10 ml/s and that normal hospital values are equivalent to a DIY-Qmean >10 ml/s, the concordance was 100 %. Our proposed DIY evaluation of urine flow, together with the International Prostatic Symptom Score (IPSS), provides a good estimate of the results of free uroflowmetry, enabling unnecessary hospital investigations to be avoided.

Does adenosine triphosphate released into voided urodynamic fluid contribute to urgency signaling in women with bladder dysfunction?

PubMed

Cheng, Ying; Mansfield, Kylie J; Allen, Wendy; Walsh, Colin A; Burcher, Elizabeth; Moore, Kate H

2010-03-01

Adenosine triphosphate released from urothelium during stretch stimulates afferent nerves and conveys information on bladder fullness. We measured adenosine triphosphate released during cystometric bladder filling in women with idiopathic detrusor overactivity and stress incontinence (controls), and assessed whether the level of released adenosine triphosphate is related to cystometric parameters. Routine cystometry was done in 51 controls and 48 women with detrusor overactivity who were 28 to 87 years old. Voided urodynamic fluid was collected and stored at -30 C. Adenosine triphosphate was measured by a bioluminescence assay. Adenosine triphosphate levels were similar in voided urodynamic fluid of controls and patients with detrusor overactivity (p = 0.79). A significant inverse correlation was seen between adenosine triphosphate and maximal cystometric capacity in controls (p = 0.013), and between voided volume and adenosine triphosphate in controls (p = 0.015) and detrusor overactivity cases (p = 0.019). A significant correlation between first desire to void and adenosine triphosphate was also noted in detrusor overactivity cases (p = 0.033) but not in controls (p = 0.58). No correlation was seen between adenosine triphosphate and detrusor pressure during filling or voiding. Adenosine triphosphate measurement in voided urodynamic fluid is a novel approach to understanding signals that may contribute to the urgency sensation (a sudden compelling desire to pass urine). The inverse correlation between adenosine triphosphate in voided urodynamic fluid and first desire to void suggests that adenosine triphosphate has a role in modulating the early filling sensation in patients with detrusor overactivity. 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Video Voiding Device for Diagnosing Lower Urinary Tract Dysfunction in Men.

PubMed

Shokoueinejad, Mehdi; Alkashgari, Rayan; Mosli, Hisham A; Alothmany, Nazeeh; Levin, Jacob M; Webster, John G

2017-01-01

We introduce a novel diagnostic Visual Voiding Device (VVD), which has the ability to visually document urinary voiding events and calculate key voiding parameters such as instantaneous flow rate. The observation of the urinary voiding process along with the instantaneous flow rate can be used to diagnose symptoms of Lower Urinary Tract Dysfunction (LUTD) and improve evaluation of LUTD treatments by providing subsequent follow-up documentations of voiding events after treatments. The VVD enables a patient to have a urinary voiding event in privacy while a urologist monitors, processes, and documents the event from a distance. The VVD consists of two orthogonal cameras which are used to visualize urine leakage from the urethral meatus, urine stream trajectory, and its break-up into droplets. A third, lower back camera monitors a funnel topped cylinder where urine accumulates that contains a floater for accurate readings regardless of the urine color. Software then processes the change in level of accumulating urine in the cylinder and the visual flow properties to calculate urological parameters. Video playback allows for reexamination of the voiding process. The proposed device was tested by integrating a mass flowmeter into the setup and simultaneously measuring the instantaneous flow rate of a predetermined voided volume in order to verify the accuracy of VVD compared to the mass flowmeter. The VVD and mass flowmeter were found to have an accuracy of ±2 and ±3% relative to full scale, respectively. A VVD clinical trial was conducted on 16 healthy male volunteers ages 23-65.

Voids in mixed-cation silicate glasses: Studies by positron annihilation lifetime and Fourier transform infrared spectroscopies

NASA Astrophysics Data System (ADS)

Reben, M.; Golis, E.; Filipecki, J.; Sitarz, M.; Kotynia, K.; Jeleń, P.; Grelowska, I.

2014-08-01

PALS in comparison with FTIR studies have been applied to investigate the structure of different oxide glasses. Three components of the positron lifetime τ (τ1 para- and τ3 ortho-positronium and τ2 intermediate lifetime component) and their intensities were obtained. The results of the calculation of mean values of positron lifetimes for the investigated glasses showed the existence of a long-living component on the positron annihilation lifetime spectra. From the Tao-Eldrup formula we can estimate the size of free volume. On the basis of the measurements we can conclude that the size and fraction of free volume reaches the biggest value for the fused silica glass. The degree of network polymerisation increases void size.

Investigation of the plastic fracture of high strength steels

NASA Technical Reports Server (NTRS)

Cox, T. B.; Low, J. R., Jr.

1972-01-01

This investigation deals in detail with the three recognized stages of plastic fracture in high strength steels, namely, void initiation, void growth, and void coalescence. The particular steels under investigation include plates from both commercial purity and high purity heats of AISI 4340 and 18 Ni, 200 grade maraging steels. A scanning electron microscope equipped with an X-ray energy dispersive analyzer, together with observations made using light microscopy, revealed methods of improving the resistance of high strength steels to plastic fracture.

Fatigue and Impact Strength of Diffusion Bonded Titanium Alloy Joints

DTIC Science & Technology

1989-02-01

likely to be due to the void level being such that the chance of a pore cluster being present at or near the test piece surface was less probable...in sub-surface crack initiation and reduced fatigue strength; it was concluded that small single voids were insignificant but clusters of voids...strength is reduced when clusters of pores are present, and is, in turn, a much more sensitive test than the tensile test. In the current work the

Marginal rigidity and history dependence in packings of attractive athermal emulsions

NASA Astrophysics Data System (ADS)

Bargteil, Dylan; Pontani, Lea-Laetitia; Brujic, Jasna

2014-03-01

The geometry and stress through particulate packings depends on the method of preparation and the interaction potential between the particles. Previously, we discovered that creaming frictionless, athermal emulsions with a short-range depletion attraction leads to an initial increase in the packing density above random close packing, followed by a monotonic decrease in density (Jorjadze et al, PNAS, 2011). This decrease is because the attractive force stabilizes loose voids, thus reducing the average coordination number, , of the packing. In order to understand the mechanism of packing creation, we investigate whether the final density is influenced by the polydispersity or the initial volume fraction of droplets, as it is in frictional packings. Finally, we compress the attractive packings by centrifugation to probe the scaling laws of pressure versus density and and compare them with those found in repulsive packings (Jorjadze et al, PRL, 2013).

Probing the contribution of internal cavities to the volume change of protein unfolding under pressure.

PubMed Central

Frye, K. J.; Royer, C. A.

1998-01-01

The structural origin of the decrease in system volume upon protein denaturation by pressure has remained a puzzle for decades. This negative volume change upon unfolding is assumed to arise globally from more intimate interactions between the polypeptide chain and water, including electrostriction of buried charges that become exposed upon unfolding, hydration of the polypeptide backbone and amino acid side chains and elimination of packing defects and internal void volumes upon unfolding of the chain. However, the relative signs and magnitudes of each of these contributing factors have not been experimentally determined. Our laboratory has probed the fundamental basis for the volume change upon unfolding of staphylococcal nuclease (Snase) using variable solution conditions and point mutants of Snase (Royer CA et al., 1993, Biochemistry 32:5222-5232; Frye KJ et al., 1996, Biochemistry 35:10234-10239). Our prior results indicate that for Snase, neither electrostriction nor polar or nonpolar hydration contributes significantly to the value of the volume change of unfolding. In the present work, we investigate the pressure induced unfolding of three point mutants of Snase in which internal cavity size is altered. The experimentally determined volume changes of unfolding for the mutants suggest that loss of internal void volume upon unfolding represents the major contributing factor to the value of the volume change of Snase unfolding. PMID:9792110

Linking initial microstructure and local response during quasistatic granular compaction

DOE PAGES

Hurley, R. C.; Lind, J.; Pagan, D. C.; ...

2017-07-24

In this study, we performed experiments combining three-dimensional x-ray diffraction and x-ray computed tomography to explore the relationship between microstructure and local force and strain during quasistatic granular compaction. We found that initial void space around a grain and contact coordination number before compaction can be used to predict regions vulnerable to above-average local force and strain at later stages of compaction. We also found correlations between void space around a grain and coordination number, and between grain stress and maximum interparticle force, at all stages of compaction. Finally, we observed grains that fracture to have an above-average initial localmore » void space and a below-average initial coordination number. In conclusion, our findings provide (1) a detailed description of microstructure evolution during quasistatic granular compaction, (2) an approach for identifying regions vulnerable to large values of strain and interparticle force, and (3) methods for identifying regions of a material with large interparticle forces and coordination numbers from measurements of grain stress and local porosity.« less

Evolution of shock through a void in foam

NASA Astrophysics Data System (ADS)

Kim, Y.; Smidt, J. M.; Murphy, T. J.; Douglass, M. R.; Devolder, B. G.; Fincke, J. R.; Schmidt, D. W.; Cardenas, T.; Newman, S. G.; Hamilton, C. E.; Sedillo, T. J.; Los Alamos, NM 87544 Team

2016-10-01

Marble implosion is an experimental campaign intended to study the effects of heterogeneous mix on fusion burn. A spherical capsule is composed of deuterated plastic foam of controlled pore (or void) size with tritium fill in pores. As capsule implosion evolves, the initially separated deuterium and tritium will mix, producing DT yields. Void evolution during implosion is of interest for the Marble campaign. A shock tube, driven by the laser at Omega, was designed to study the evolution of a shock through a foam-filled ``void'' and subsequent void evolution. Targets were comprised of a 100 mg/cc CH foam tube containing a 200-µm diameter, lower density doped foam sphere. High-quality, radiographic images were obtained from both 2% iodine-doped in plastic foam and 15% tin-doped in aerogel foam. These experiments will be used to inform simulations.

The evolution of void-filled cosmological structures

NASA Technical Reports Server (NTRS)

Regos, Eniko; Geller, Margaret J.

1991-01-01

1D, 2D, and 3D simulations are used here to investigate the salient features in the evolution of void-filled cosmological structures in universes with arbitrary values of Omega. It is found that the growth of a void as a function of time decreases significantly at the time corresponding to Omega = 0.5. In models constructed in 2D and 3D, suitable initial conditions lead to cellular structure with faceted voids similar to those observed in redshift surveys. Matter compressed to planes flows more rapidly toward condensations at the intersections than would be expected for spherical infall. The peculiar streaming velocities for void diameters of 5000 km/s should be observable. The simulations provide a more physical basis and dynamics for the bubbly and Voronois tesselation models used to derive statistical properties of cellular large-scale structure.

Detecting self-ion irradiation-induced void swelling in pure copper using transient grating spectroscopy

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

Dennett, C. A.; So, K. P.; Kushima, A.

Irradiation-induced void swelling remains a major challenge to nuclear reactor operation. Swelling may take years to initiate and often results in rapid material property degradation once started. Alloy development for advanced nuclear systems will require rapid characterization of the swelling breakaway dose in new alloys, yet this capability does not yet exist. In this paper, we demonstrate that transient grating spectroscopy (TGS) can detect void swelling in single crystal copper via changes in surface acoustic wave (SAW) velocity. Scanning transmission electron microscopy (STEM) links the TGS-observed changes with void swelling-induced microstructural evolution. Finally, these results are considered in the contextmore » of previous work to suggest that in situ TGS will be able to rapidly determine when new bulk materials begin void swelling, shortening alloy development and testing times.« less

Detecting self-ion irradiation-induced void swelling in pure copper using transient grating spectroscopy

DOE PAGES

Dennett, C. A.; So, K. P.; Kushima, A.; ...

2017-12-20

Irradiation-induced void swelling remains a major challenge to nuclear reactor operation. Swelling may take years to initiate and often results in rapid material property degradation once started. Alloy development for advanced nuclear systems will require rapid characterization of the swelling breakaway dose in new alloys, yet this capability does not yet exist. In this paper, we demonstrate that transient grating spectroscopy (TGS) can detect void swelling in single crystal copper via changes in surface acoustic wave (SAW) velocity. Scanning transmission electron microscopy (STEM) links the TGS-observed changes with void swelling-induced microstructural evolution. Finally, these results are considered in the contextmore » of previous work to suggest that in situ TGS will be able to rapidly determine when new bulk materials begin void swelling, shortening alloy development and testing times.« less

Void Growth and Coalescence in Dynamic Fracture of FCC and BCC Metals - Molecular Dynamics Study

NASA Astrophysics Data System (ADS)

Seppälä, Eira

2004-03-01

In dynamic fracture of ductile metals, the state of tension causes the nucleation of voids, typically from inclusions or grain boundary junctions, which grow and ultimately coalesce to form the fracture surface. Significant plastic deformation occurs in the process, including dislocations emitted to accommodate the growing voids. We have studied at the atomistic scale growth and coalescence processes of voids with concomitant dislocation formation. Classical molecular dynamics (MD) simulations of one and two pre-existing spherical voids initially a few nanometers in radius have been performed in single-crystal face-centered-cubic (FCC) and body-centered-cubic (BCC) lattices under dilational strain with high strain-rates. Million atom simulations of single void growth have been done to study the effect of stress triaxiality,^1 along with strain rate and lattice-structure dependence. An interesting prolate-to-oblate transition in the void shape in uniaxial expansion has been observed and quantitatively analyzed. The simulations also confirm that the plastic strain results directly from the void growth. Interaction and coalescence between two voids have been studied utilizing a parallel MD code in a seven million atom system. In particular, the movement of centers of the voids, linking of the voids, and the shape changes in vicinity of the other void are studied. Also the critical intervoid ligament distance after which the voids can be treated independently has been searched. ^1 E. T. Seppälä, J. Belak, and R. E. Rudd, cond-mat/0310541, submitted to Phys. Rev. B. Acknowledgment: This work was done in collaboration with Dr. James Belak and Dr. Robert E. Rudd, LLNL. It was performed under the auspices of the US Dept. of Energy at the Univ. of Cal./Lawrence Livermore National Laboratory under contract no. W-7405-Eng-48.

The effect of rectal distension on bladder function in patients with overactive bladder.

PubMed

Akl, Mohamed N; Jacob, Kristina; Klauschie, Jennifer; Crowell, Michael D; Kho, Rosanne M; Cornella, Jeffrey L

2012-04-01

To investigate the effect of rectal distension on bladder sensation volumes and the number of detrusor contractions in patients with overactive bladder (OAB) symptoms. A prospective randomized study included patients with OAB symptoms. Multichannel urodynamic studies were completed with and without rectal balloon distension. Bladder sensation volumes and detrusor contractions were compared. Twenty-six patients were included in the study. The mean age was 67 years and mean BMI was 28.3 kg/m(2) . Bladder sensation volumes were lower with rectal distention as follows: normal desire to void (139 ml SD, ±114 vs. 197 ml SD ±150, P = 0.01), strong desire to void (260 ml SD ±171 vs. 330 ml SD ±172, P = 0.01), and maximum cystometric capacity (326 ml SD ±183 vs. 403 ml SD ±180, P = 0.0001). There was no difference in the number of detrusor contractions or the bladder volume at which the first detrusor contraction had occurred with and without rectal distension. Rectal distention in patients with OAB symptoms significantly lowered bladder sensation volumes (normal desire, strong desire, and maximal capacity). Copyright © 2012 Wiley Periodicals, Inc.

The effectiveness of dried cranberries ( Vaccinium macrocarpon) in men with lower urinary tract symptoms.

PubMed

Vidlar, Ales; Vostalova, Jitka; Ulrichova, Jitka; Student, Vladimir; Stejskal, David; Reichenbach, Richard; Vrbkova, Jana; Ruzicka, Filip; Simanek, Vilim

2010-10-01

Lower urinary tract symptoms (LUTS) are a common condition in older men. The objective of the present study was to evaluate the efficacy and tolerability of cranberry (Vaccinium macrocarpon) powder in men at risk of prostate disease with LUTS, elevated prostate-specific antigen (PSA), negative prostate biopsy and clinically confirmed chronic non-bacterial prostatitis. Forty-two participants received either 1500 mg of the dried powdered cranberries per d for 6 months (cranberry group; n 21) or no cranberry treatment (control group; n 21). Physical examination, International Prostate Symptom Score, quality of life (QoL), five-item version of the International Index of Erectile Function (IIEF-5), basic clinical chemistry parameters, haematology, Se, testosterone, PSA (free and total), C-reactive protein (CRP), antioxidant status, transrectal ultrasound prostate volume, urinary flow rate, ultrasound-estimated post-void residual urine volume at baseline, and at 3 and 6 months, and urine ex vivo anti-adherence activity were determined in all subjects. In contrast to the control group, patients in the cranberry group had statistically significant improvement in International Prostate Symptom Score, QoL, urination parameters including voiding parameters (rate of urine flow, average flow, total volume and post-void residual urine volume), and lower total PSA level on day 180 of the study. There was no influence on blood testosterone or serum CRP levels. There was no statistically significant improvement in the control group. The results of the present trial are the first firm evidence that cranberries may ameliorate LUTS, independent of benign prostatic hyperplasia or C-reactive protein level.

A cutoff value based on analysis of a reference population decreases overestimation of the prevalence of nocturnal polyuria.

PubMed

van Haarst, Ernst P; Bosch, J L H Ruud

2012-09-01

We sought criteria for nocturnal polyuria in asymptomatic, nonurological adults of all ages by reporting reference values of the ratio of daytime and nighttime urine volumes, and finding nocturia predictors. Data from a database of frequency-volume charts from a reference population of 894 nonurological, asymptomatic volunteers of all age groups were analyzed. The nocturnal polyuria index and the nocturia index were calculated and factors influencing these values were determined by multivariate analysis. The nocturnal polyuria index had wide variation but a normal distribution with a mean ± SD of 30% ± 12%. The 95th percentile of the values was 53%. Above this cutoff a patient had nocturnal polyuria. This value contrasts with the International Continence Society definition of 33% but agrees with several other reports. On multivariate regression analysis with the nocturnal polyuria index as the dependent variable sleeping time, maximum voided volume and age were the covariates. However, the increase in the nocturnal polyuria index by age was small. Excluding polyuria and nocturia from analysis did not alter the results in a relevant way. The nocturnal voiding frequency depended on sleeping time and maximum voided volume but most of all on the nocturia index. The prevalence of nocturnal polyuria is overestimated. We suggest a new cutoff value for the nocturnal polyuria index, that is nocturnal polyuria exists when the nocturnal polyuria index exceeds 53%. The nocturia index is the best predictor of nocturia. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Accuracy of the Generalized Self-Consistent Method in Modelling the Elastic Behaviour of Periodic Composites

NASA Technical Reports Server (NTRS)

Walker, Kevin P.; Freed, Alan D.; Jordan, Eric H.

1993-01-01

Local stress and strain fields in the unit cell of an infinite, two-dimensional, periodic fibrous lattice have been determined by an integral equation approach. The effect of the fibres is assimilated to an infinite two-dimensional array of fictitious body forces in the matrix constituent phase of the unit cell. By subtracting a volume averaged strain polarization term from the integral equation we effectively embed a finite number of unit cells in a homogenized medium in which the overall stress and strain correspond to the volume averaged stress and strain of the constrained unit cell. This paper demonstrates that the zeroth term in the governing integral equation expansion, which embeds one unit cell in the homogenized medium, corresponds to the generalized self-consistent approximation. By comparing the zeroth term approximation with higher order approximations to the integral equation summation, both the accuracy of the generalized self-consistent composite model and the rate of convergence of the integral summation can be assessed. Two example composites are studied. For a tungsten/copper elastic fibrous composite the generalized self-consistent model is shown to provide accurate, effective, elastic moduli and local field representations. The local elastic transverse stress field within the representative volume element of the generalized self-consistent method is shown to be in error by much larger amounts for a composite with periodically distributed voids, but homogenization leads to a cancelling of errors, and the effective transverse Young's modulus of the voided composite is shown to be in error by only 23% at a void volume fraction of 75%.

X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

NASA Astrophysics Data System (ADS)

Lu, Haizhu

Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

Impact of convenience void in a bladder diary with urinary perception grade to assess overactive bladder symptoms: a community-based study.

PubMed

Honjo, Hisashi; Kawauchi, Akihiro; Nakao, Masahiro; Ukimura, Osamu; Kitakoji, Hiroshi; Miki, Tsuneharu

2010-09-01

Bladder diaries including bladder perception grade were analyzed to assess convenience void (CV) in community-dwelling women 40 years of age or older. A total of 310 women completed a 3-day bladder diary with a grade for bladder perception. The grade was defined on scores 0-5 as follows: 0 = No bladder sensation, 1 = Sensation of bladder filling without desire to void, 2 = Desire to void, 3 = Strong desire to void, 4 = Urgency without urge urinary incontinence (UUI), and 5 = Urge incontinence episode. CV was defined as void without desire to void: when the grade was 0, CV in a narrow sense, and when 0 or 1, CV in a broad sense. The incidence of CV in the broad sense significantly decreased with age. Of the 310 women, 48 (15.5%) had overactive bladder (OAB) symptoms on the medical interview, including 37 (11.9%) without UUI (OAB-Dry) and 11 (3.5%) with UUI (OAB-Wet). Of the remaining 262 women, 111 (35.8%), who had urgency but a urinary frequency of 7 or less, and another 141 (48.7%) were classified into the Normal with Urgency and Normal without Urgency groups, respectively. The incidence of CV in a broad sense in the Normal without Urgency group was significantly greater than that in the Normal with Urgency and OAB-Wet groups. The mean voided volumes of CV in the broad sense in the OAB-Wet group were significantly smaller than those in the other three groups. The evaluation of CV may be a new tool in assessing storage condition and voiding dysfunction. © 2010 Wiley-Liss, Inc.

A urine volume measurement system

NASA Technical Reports Server (NTRS)

Poppendiek, H. F.; Mouritzen, G.; Sabin, C. M.

1972-01-01

An improved urine volume measurement system for use in the unusual environment of manned space flight is reported. The system utilizes a low time-constant thermal flowmeter. The time integral of the transient response of the flowmeter gives the urine volume during a void as it occurs. In addition, the two phase flows through the flowmeter present no problem. Developments of the thermal flowmeter and a verification of the predicted performance characteristics are summarized.

Dimensionality effects in void-induced explosive sensitivity

DOE PAGES

Herring, Stuart Davis; Germann, Timothy Clark; Gronbech-Jensen, Niels

2016-09-02

Here, the dimensionality of defects in high explosives controls their heat generation and the expansion of deflagrations from them. We compare the behaviour of spherical voids in three dimensions to that of circular voids in two dimensions. The behaviour is qualitatively similar, but the additional focusing along the extra transverse dimension significantly reduces the piston velocity needed to initiate reactions. However, the reactions do not grow as well in three dimensions, so detonations require larger piston velocities. Pressure exponents are seen to be similar to those for the two-dimensional system.

Flight experiment of thermal energy storage

NASA Technical Reports Server (NTRS)

Namkoong, David

1989-01-01

Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. These salts store energy as a heat of fusion, thereby transferring heat to the fluid at constant temperature during shade. The principal feature of fluorides that must be taken into account is the change in volume that occurs with melting and freezing. Salts shrink as they solidify, a change reaching 30 percent for some salts. The location of voids that form as result of the shrinkage is critical when the solar dynamic system reemerges into the sun. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The code is capable of analysis under microgravity as well as 1 g. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity. Each test package will be installed in a Getaway Special container to be carried by the shuttle. The package will be self-contained and independent of shuttle operations other than the initial opening of the container lid and the final closing of the lid. Upon the return of the test package from flight, the TES container will be radiographed and finally partitioned to examine the exact location and shape of the void. Visual inspection of the void and the temperature data during flight will constitute the bases for code verification.

WE-AB-204-03: A Novel 3D Printed Phantom for 4D PET/CT Imaging and SIB Radiotherapy Verification

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

Soultan, D; Murphy, J; Moiseenko, V

Purpose: To construct and test a 3D printed phantom designed to mimic variable PET tracer uptake seen in lung tumor volumes. To assess segmentation accuracy of sub-volumes of the phantom following 4D PET/CT scanning with ideal and patient-specific respiratory motion. To plan, deliver and verify delivery of PET-driven, gated, simultaneous integrated boost (SIB) radiotherapy plans. Methods: A set of phantoms and inserts were designed and manufactured for a realistic representation of lung cancer gated radiotherapy steps from 4D PET/CT scanning to dose delivery. A cylindrical phantom (40x 120 mm) holds inserts for PET/CT scanning. The novel 3D printed insert dedicatedmore » to 4D PET/CT mimics high PET tracer uptake in the core and lower uptake in the periphery. This insert is a variable density porous cylinder (22.12×70 mm), ABS-P430 thermoplastic, 3D printed by uPrint SE Plus with inner void volume (5.5×42 mm). The square pores (1.8×1.8 mm2 each) fill 50% of outer volume, resulting in a 2:1 SUV ratio of PET-tracer in the void volume with respect to porous volume. A matching in size cylindrical phantom is dedicated to validate gated radiotherapy. It contains eight peripheral holes matching the location of the porous part of the 3D printed insert, and one central hole. These holes accommodate adaptors for Farmer-type ion chamber and cells vials. Results: End-to-end test were performed from 4D PET/CT scanning to transferring data to the planning system and target volume delineation. 4D PET/CT scans were acquired of the phantom with different respiratory motion patterns and gating windows. A measured 2:1 18F-FDG SUV ratio between inner void and outer volume matched the 3D printed design. Conclusion: The novel 3D printed phantom mimics variable PET tracer uptake typical of tumors. Obtained 4D PET/CT scans are suitable for segmentation, treatment planning and delivery in SIB gated treatments of NSCLC.« less

Evaluation of the incidence and risk factors associated with persistent frequency in interstitial cystitis/bladder pain syndrome and the efficacy of antimuscarinic treatment.

PubMed

Kim, Aram; Hoe, Kyeong-Ok; Shin, Jung Hyun; Choo, Myung-Soo

2017-09-01

To investigate the incidence and risk factors associated with persistent urinary frequency, and to evaluate the efficacy of antimuscarinic treatment. Interstitial cystitis/bladder pain syndrome (IC/BPS) patients complaining of persistent urinary frequency despite improved pain were evaluated. Before initial conventional treatment, each patient completed a voiding diary and symptom questionnaires. After conventional treatment, patients were divided according to the presence of pain and frequency. Improved pain was defined as lesser than 3 points in visual analogue scale, and persistent urinary frequency as >10 times/d. Risk factors for persistent frequency were identified through multivariate analysis. The efficacy of antimuscarinic treatment was assessed by the mean change of frequency. Of 171 IC/BPS patients treated with conventional therapy, 132 had improved pain after 3 months, but 72 had persistent frequency (72 of 132, 54.5%). Patients with persistent frequency had lower voided volume (p=0.008), lower maximal flow rate (p<0.001), lower maximal bladder capacity (p=0.003), and more frequent micturition (p<0.001) at baseline compared to those with improved frequency. Patients who took antimuscarinic agents showed slightly decreased urinary frequency, from 14.6 times/d to 13.5 times/d (p=0.438) after 3 months of medication. No patients showed more than a 20% decrease in frequency with antimuscarinics. About half of the patients with IC/BPS showed persistent frequency, with poor voiding function identified as a risk factor; antimuscarinic treatment was not effective in these patients.

Comparison of high-pressure CO 2 sorption isotherms on Eastern and Western US coals

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

Romanov, V; Hur, T -B; Fazio, J

2013-10-01

Accurate estimation of carbon dioxide (CO 2) sorption capacity of coal is important for planning the CO 2 sequestration efforts. In this work, we investigated sorption and swelling behavior of several Eastern and Western US coal samples from the Central Appalachian Basin and from San Juan Basin. The CO 2 sorption isotherms have been completed at 55°C for as received and dried samples. The role of mineral components in coal, the coal swelling, the effects of temperature and moisture, and the error propagation have been analyzed. Changes in void volume due to dewatering and other factors such as temporary cagingmore » of carbon dioxide molecules in coal matrix were identified among the main factors affecting accuracy of the carbon dioxide sorption isotherms. The (helium) void volume in the sample cells was measured before and after the sorption isotherm experiments and was used to build the volume-corrected data plots.« less

Cavitation instability as a trigger of aneurysm rupture.

PubMed

Volokh, K Y

2015-10-01

Aneurysm formation and growth is accompanied by microstructural alterations in the arterial wall. Particularly, the loss of elastin may lead to tissue disintegration and appearance of voids or cavities at the micron scale. Unstable growth and coalescence of voids may be a predecessor and trigger for the onset of macroscopic cracks. In the present work, we analyze the instability of membrane (2D) and bulk (3D) voids under hydrostatic tension by using two experimentally calibrated constitutive models of abdominal aortic aneurysm enhanced with energy limiters. The limiters provide the saturation value for the strain energy, which indicates the maximum energy that can be stored and dissipated by an infinitesimal material volume. We find that the unstable growth of voids can start when the critical stress is considerably less than the aneurysm strength. Moreover, this critical stress may even approach the arterial wall stress in the physiological range. This finding suggests that cavitation instability can be a rational indicator of the aneurysm rupture.

Does instruction to eliminate coffee, tea, alcohol, carbonated, and artificially sweetened beverages improve lower urinary tract symptoms: A Prospective Trial

PubMed Central

Miller, Janis M.; Garcia, Caroline E.; Hortsch, Sarah Becker; Guo, Ying; Schimpf, Megan O.

2016-01-01

Purpose Common advice for lower urinary tract symptoms (LUTS) of frequency, urgency and related bother includes elimination of potentially irritating beverages (coffee, tea, alcohol, and carbonated and/or artificially sweetened beverages). The purpose of this study was to determine compliance with standardized instruction to eliminate these potentially irritating beverages, whether LUTS improved after instruction, and if symptoms worsened with partial reintroduction. Design The three-phase fixed sequence design was: 1) baseline, 2) eliminate potentially irritating beverages listed above, and 3) reintroduce at 50% of baseline volume, with a washout period between each 3-day phase. We asked participants to maintain total intake volume by swapping in equal amounts of non-potentially irritating beverages (primarily water). Subjects and Setting The study sample comprised 30 community-dwelling women recruited through newspaper advertisement. Methods Quantification measures included 3-day voiding diaries and detailed beverage intake, and LUTS questionnaires completed during each phase. Results During Phase 2, we found significant reduction in potentially irritating beverages but complete elimination was rare. Despite the protocol demands, total beverage intake was not stable; mean (± standard deviation) daily total intake volume dropped by 6.2±14.9oz (p=0.03) during Phase 2. In Phase 3, the volume of total beverage intake returned to baseline, but intake of potentially irritating beverages also returned to near baseline rather than 50% as requested by protocol. Despite this incomplete adherence to study protocols, women reported reduction in symptoms of urge, inability to delay voiding, and bother during both phases (p≤0.01). The number of voids per day decreased on average by 1.3 and 0.9 voids during phases 2 and 3 respectively (p=0.002 and p=0.035). Conclusions Education to reduce potentially irritating beverages resulted in improvement in LUTS. However, eliminating potentially irritating beverages was difficult to achieve and maintain. Study findings do not allow us to determine if LUTS improvement was attributable to intake of fewer potentially irritating beverages, reduced intake of all beverages, the effect of self-monitoring, or some combination of these factors. PMID:26727685

Does Instruction to Eliminate Coffee, Tea, Alcohol, Carbonated, and Artificially Sweetened Beverages Improve Lower Urinary Tract Symptoms?: A Prospective Trial.

PubMed

Miller, Janis M; Garcia, Caroline E; Hortsch, Sarah Becker; Guo, Ying; Schimpf, Megan O

2016-01-01

Common advice for lower urinary tract symptoms (LUTS) such as frequency, urgency, and related bother includes elimination of potentially irritating beverages (coffee, tea, alcohol, and carbonated and/or artificially sweetened beverages). The purpose of this study was to determine compliance with standardized instruction to eliminate these potentially irritating beverages, whether LUTS improved after instruction, and whether symptoms worsened with partial reintroduction. The 3-phase fixed sequence design was (1) baseline, (2) eliminate potentially irritating beverages listed above, and (3) reintroduce at 50% of baseline volume, with a washout period between each 3-day phase. We asked participants to maintain total intake volume by swapping in equal amounts of nonpotentially irritating beverages (primarily water). The study sample comprised 30 community-dwelling women recruited through newspaper advertisement. Quantification measures included 3-day voiding diaries and detailed beverage intake, and LUTS questionnaires completed during each phase. During Phase 2, we found significant reduction in potentially irritating beverages but complete elimination was rare. Despite protocol demands, total beverage intake was not stable; mean (± standard deviation) daily total intake volume dropped by 6.2 ± 14.9 oz (P = .03) during Phase 2. In Phase 3, the volume of total beverage intake returned to baseline, but the intake of potentially irritating beverages also returned to near baseline rather than 50% as requested by protocol. Despite this incomplete adherence to study protocols, women reported reduction in symptoms of urge, inability to delay voiding, and bother during both phases (P ≤ .01). The number of voids per day decreased on average by 1.3 and 0.9 voids during Phases 2 and 3, respectively (P = .002 and P = .035). Education to reduce potentially irritating beverages resulted in improvement in LUTS. However, eliminating potentially irritating beverages was difficult to achieve and maintain. Study findings do not allow us to determine whether LUTS improvement was attributable to intake of fewer potentially irritating beverages, reduced intake of all beverages, the effect of self-monitoring, or some combination of these factors.

Vesicoureteral reflux and urinary tract infection in children with a history of prenatal hydronephrosis--should voiding cystourethrography be performed in cases of postnatally persistent grade II hydronephrosis?

PubMed

Estrada, Carlos R; Peters, Craig A; Retik, Alan B; Nguyen, Hiep T

2009-02-01

The clinical relevance of prenatal hydronephrosis is not well-defined. We determined the risk of febrile urinary tract infection in the absence of screening for vesicoureteral reflux, and whether postnatal voiding cystourethrography should be performed in patients with a history of prenatal hydronephrosis and postnatally persistent Society for Fetal Urology grade II hydronephrosis. From a longitudinal database of patients with prenatal hydronephrosis maintained since 1998 we identified those with postnatally persistent grade II hydronephrosis. This cohort was divided into patients who were and were not screened with an initial voiding cystourethrogram. The rates of vesicoureteral reflux and development of febrile urinary tract infection were determined. Of 2,076 patients with prenatal hydronephrosis 1,514 had grade II hydronephrosis. Of the patients 76% underwent an initial voiding cystourethrogram and vesicoureteral reflux was found in 28%. There was no relation between laterality of hydronephrosis and incidence of vesicoureteral reflux. There was no difference between nonscreened and screened patients with respect to gender and laterality of hydronephrosis. Urinary tract infection developed in 1.3% of the patients who were screened and did not have vesicoureteral reflux and, therefore, were not receiving antibiotics. Of the screened patients with vesicoureteral reflux who were receiving prophylactic antibiotics urinary tract infection developed in 1.6% at a mean age of 9.4 months. In 363 patients who did not undergo an initial voiding cystourethrogram we estimated (based on the screened population) that 101 would have vesicoureteral reflux and 5 would have a urinary tract infection. However, a febrile urinary tract infection developed in 16 patients (4.4% overall, p <0.0001) at a mean age of 9.3 months. Voiding cystourethrogram performed in these 16 patients revealed vesicoureteral reflux in 12. Of all the patients with a urinary tract infection who were ultimately observed to have vesicoureteral reflux (including those initially screened and those discovered to have reflux after a urinary tract infection) the laterality of hydronephrosis, grade of reflux and laterality of reflux were comparable. In patients with a history of prenatal hydronephrosis who are observed to have postnatally persistent grade II hydronephrosis identification of vesicoureteral reflux and use of prophylactic antibiotics significantly reduce the risk of febrile urinary tract infection. Therefore, we recommend that patients with a history of prenatal hydronephrosis and postnatally persistent hydronephrosis be screened with voiding cystourethrography early in life, and be placed on prophylactic antibiotics until the screening results are known.

One dimensional motion of interstitial clusters and void growth in Ni and Ni alloys

NASA Astrophysics Data System (ADS)

Yoshiie, T.; Ishizaki, T.; Xu, Q.; Satoh, Y.; Kiritani, M.

2002-12-01

One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. In this paper, the effect of 2 at.% alloying with elements Si (volume size factor to Ni: -5.81%), Cu (7.18%), Ge (14.76%) and Sn (74.08%) in Ni on 1-D motion of interstitial clusters and void growth was studied. In neutron irradiated pure Ni, Ni-Cu and Ni-Ge, well developed dislocation networks and voids in the matrix, and no defects near grain boundaries were observed at 573 K to a dose of 0.4 dpa by transmission electron microscopy. No voids were formed and only interstitial type dislocation loops were observed near grain boundaries in Ni-Si and Ni-Sn. The reaction kinetics analysis which included the point defect flow into planar sink revealed the existence of 1-D motion of interstitial clusters in Ni, Ni-Cu and Ni-Ge, and lack of such motion in Ni-Si and Ni-Sn. In Ni-Sn and Ni-Si, the alloying elements will trap interstitial clusters and thereby reduce the cluster mobility, which lead to the reduction in void growth.

Hierarchical analysis of the degradation of fibre-reinforced polymers under the presence of void imperfections

PubMed Central

2016-01-01

The subject of this work is the investigation of the influence of voids on the mechanical properties of fibre-reinforced polymers (FRPs) under compression loading. To specify the damage accumulation of FRPs in the presence of voids, the complex three-dimensional structure of the composite including voids was analysed and a reduced mechanical model composite was derived. The hierarchical analysis of the model composite on a micro-scale level implies the description of the stress and strain behaviour of the matrix using the photoelasticity technique and digital image correlation technology. These studies are presented along with an analytical examination of the stability of a single fibre. As a result of the experimental and analytical studies, the stiffness of the matrix and fibre as well as their bonding, the initial fibre orientation and the fibre diameter have the highest impact on the failure initiation. All these facts lead to a premature fibre–matrix debonding with ongoing loss of stability of the fibre and followed by kink-band formation. Additional studies on the meso-scale of transparent glass FRPs including a unique void showed that the experiments carried out on the model composites could be transferred to real composites. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’. PMID:27242296

Analysis of Dislocation Emission during Microvoid Growth in Ductile Metals

NASA Astrophysics Data System (ADS)

Belak, James; Rudd, Robert E.

2001-03-01

Fracture in ductile metals occurs through the nucleation and growth of microscopic voids. This talk focuses on the initial stage when dislocations are first emitted from the void surface. The model system consists of a spherical void in an otherwise perfect crystal under triaxial tension. The stress field is calculated using continuum techniques, both finite element and analytic forms due to Eshelby, and compared with large-scale molecular dynamics (MD) simulation. The stress field is used to derive a criterion for dislocation nucleation on the glide planes intersecting the void surface. The critical resolved shear stress and the unstable stacking fault energy for the strain at the surface are used to compare to the critical stress for void growth in the MD simulations. Acknowledgement: This work was performed under the auspices of the US Dept. of Energy at the University of California/Lawrence Livermore National Laboratory under contract no. W-7405-Eng-48. [1] J. Belak, "On the nucleation and growth of voids at high strain-rates," J. Comp.-Aided Mater. Design 5, 193 (1998).

Roles of Polyuria and Hyperglycemia on Bladder Dysfunction in Diabetes

PubMed Central

Xiao, Nan; Wang, Zhiping; Huang, Yexiang; Daneshgari, Firouz; Liu, Guiming

2014-01-01

Purpose Diabetes mellitus (DM) causes diabetic bladder dysfunction (DBD). We aimed to identify the pathogenic roles of polyuria and hyperglycemia on DBD in rats. Materials and Methods Seventy-two female Sprague-Dawley rats were divided: age-matched controls (control), sham urinary diversion (sham), urinary diversion (UD), streptozotocin-induced diabetes after sham UD (DM), streptozotocin-induced diabetes after UD (UD+DM), and 5% sucrose-induced diuresis after sham UD (DIU). UD was performed by ureterovaginostomy 10d before DM induction. Animals were evaluated 20 wks after DM or diuresis induction. We measured 24-hr drinking and voiding volumes and cystometry (CMG). Bladders were harvested for quantification of smooth muscle, urothelium, and collagen. We measured nitrotyrosine and manganese superoxide dismutase (MnSOD) in bladder. Results Diabetes and diuresis caused increases in drinking volume, voiding volume and bladder weight. Bladder weights decreased in the UD and UD+DM groups. Intercontractile intervals, voided volume, and compliance increased in the DIU and DM groups, decreased in the UD, and further decreased in the UD+DM group. The total cross-sectional tissue, smooth muscle and urothelium areas increased in the DIU and DM groups, and decreased in the UD and UD+DM groups. As percentages of total tissue area, collagen decreased in the DIU and DM groups, and increased in the UD and UD+DM groups, and smooth muscle and urothelium decreased in the UD and UD+DM groups. Nitrotyrosine and MnSOD increased in DM and UD+DM rats. Conclusions Polyuria induced bladder hypertrophy, while hyperglycemia induced substantial oxidative stress in the bladder, which may play a pathogenic role in late stage DBD. PMID:22999997

Social stress in mice induces voiding dysfunction and bladder wall remodeling

PubMed Central

Chang, Andy; Butler, Stephan; Sliwoski, Joanna; Valentino, Rita; Canning, Douglas

2009-01-01

Several studies have anecdotally reported the occurrence of altered urinary voiding patterns in rodents exposed to social stress. A recent study characterized the urodynamic and central changes in a rat model of social defeat. Here, we describe a similar voiding phenotype induced in mice by social stress and in addition we describe potential molecular mechanisms underlying the resulting bladder wall remodeling. The mechanism leading to the altered voiding habits and underlying bladder phenotype may be relevant to the human syndrome of dysfunctional voiding which is thought to have a psychological component. To better characterize and investigate social stress-induced bladder wall hypertrophy, FVB mice (6 wk old) were randomized to either social stress or control manipulation. The stress involved repeated cycles of a 1-h direct exposure to a larger aggressive C57Bl6 breeder mouse followed by a 23-h period of barrier separation over 4 wk. Social stress resulted in altered urinary voiding patterns suggestive of urinary retention and increased bladder mass. In vivo cystometry revealed an increased volume at micturition with no change in the voiding pressure. Examination of these bladders revealed increased nuclear expression of the transcription factors MEF-2 and NFAT, as well as increased expression of the myosin heavy chain B isoform mRNA. BrdU uptake was increased within the urothelium and lamina propria layers in the social stress group. We conclude that social stress induces urinary retention that ultimately leads to shifts in transcription factors, alterations in myosin heavy chain isoform expression, and increases in DNA synthesis that mediate bladder wall remodeling. Social stress-induced bladder dysfunction in rodents may provide insight into the underlying mechanisms and potential treatment of dysfunctional voiding in humans. PMID:19587139

Void Management in MEPHISTO and Other Space Experiments

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III; Johnston, J. Christopher; Wei, Bingbo

1998-01-01

The second flight of NASA's Shuttle Flight experiment program known as MEPHISTO suffered from a void in the liquid portion of the sample, even though a piston arrangement was in place to keep the ampoule filled. In preparations for the next flight of the MEPHISTO furnace an animated computer program, called MEPHISTO Volume Visualizer (MVV), was written to help avoid the formation of unwanted voids. A piston system on MEPHISTO has the ability to move approximately 5 mm in compression, to accommodate expansion of the solid during heating; then from the completely compressed position, the piston can move up to 25 mm in towards the sample, effectively making the ampoule smaller and hopefully eliminating any voids. Due to the nature of the piston design and ampoule and sample arrangement, the piston has gotten stuck during normal directional solidification; this creates the risk of a void. To eliminate such a void, the liquid in the hot zones of the furnace can be heated, thereby expanding the liquid and consuming any void. The problem with this approach is that if the liquid is heated too much an overpressure could result, breaking the ampoule and ending the experiment catastrophically. The MVV has been found to be a useful tool in the assessment of the risks associated with the formation of a void and the additional heating of the liquid in the hot zone of this Bridgman type furnace. The MVV software will be discussed and copies available; it is written in the Delphi 2 programming language and runs under Windows 95 and NT. The strategies used in other flight experiments, such as the Isothermal Dendritic Growth Experiment, will also be presented.

Newtonian self-gravitating system in a relativistic huge void universe model

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

Nishikawa, Ryusuke; Nakao, Ken-ichi; Yoo, Chul-Moon, E-mail: ryusuke@sci.osaka-cu.ac.jp, E-mail: knakao@sci.osaka-cu.ac.jp, E-mail: yoo@gravity.phys.nagoya-u.ac.jp

We consider a test of the Copernican Principle through observations of the large-scale structures, and for this purpose we study the self-gravitating system in a relativistic huge void universe model which does not invoke the Copernican Principle. If we focus on the the weakly self-gravitating and slowly evolving system whose spatial extent is much smaller than the scale of the cosmological horizon in the homogeneous and isotropic background universe model, the cosmological Newtonian approximation is available. Also in the huge void universe model, the same kind of approximation as the cosmological Newtonian approximation is available for the analysis of themore » perturbations contained in a region whose spatial size is much smaller than the scale of the huge void: the effects of the huge void are taken into account in a perturbative manner by using the Fermi-normal coordinates. By using this approximation, we derive the equations of motion for the weakly self-gravitating perturbations whose elements have relative velocities much smaller than the speed of light, and show the derived equations can be significantly different from those in the homogeneous and isotropic universe model, due to the anisotropic volume expansion in the huge void. We linearize the derived equations of motion and solve them. The solutions show that the behaviors of linear density perturbations are very different from those in the homogeneous and isotropic universe model.« less

Optimisation des proprietes physiques d'un composite carbone epoxy fabrique par le procede RFI

NASA Astrophysics Data System (ADS)

Koanda, Mahamat Mamadou Lamine

The RFI (Resin Film Infusion) process is a composite materials manufacturing process. Especially known for the small investment it requires, RFI processes are more and more widely used in the aeronautical industry. However a number of aspects of this process are still not well controlled. The quality of the final part depends on which process is used. In the case of RFI, controlling physical characteristics such as thickness, fiber volume fraction or void content remains a major challenge. This dissertation deals with the optimization of the physical properties of a carbon composite manufactured with RFI processes. The ASTMD3171 and ASTMD792 standards were used to measure the void content and fiber volume fraction. First, we introduced different layup sequences in the RFI process and evaluate their impact on the physical properties of the final product. The experiments show the primary mode A, with the resin film at the bottom, resulting in much better quality with controlled fiber volume fraction and void content. Mode B (film in the symmetrical plane) yields results identical to mode A except more irregular thicknesses. Mode C (symmetrical film in the laminate) produces locally unacceptable void contents. Mode D (resin film on the top of the laminate) yields much better results than mode A with the exception of the more irregular thicknesses. Making gaps and overlaps with the resin film has negative effects beyond 2.54cm (one inch) and should be avoided. Several C-scan observations of the manufactured samples showed a large accumulation of porosity in the resin rich areas, as well as surface defects. Ultimately we analyzed the cure cycle in light of the thermodynamic porosity models. It is evident that the diffusion phenomenon is essential in this process. Therefore a better conditioning of the resin film made by Cytec is required. An optimal design with a cycle stop and pressure lag yields the optimal cure cycle for the RFI process.

Recovery of storage and emptying functions of the urinary bladder after spinal anesthesia with lidocaine and with bupivacaine in men.

PubMed

Kamphuis, E T; Ionescu, T I; Kuipers, P W; de Gier, J; van Venrooij, G E; Boon, T A

1998-02-01

The aim of this study was to evaluate and compare the effects of spinal anesthesia with lidocaine and with bupivacaine on urinary bladder function in healthy men who were scheduled for minor orthopaedic surgical procedures. Twenty men were randomly allocated to receive either bupivacaine or lidocaine. Before spinal anesthesia, filling cystometry was performed with the patient in the supine position and a pressure flow study was done with the patient in the standing position. After operation, cystometric measurements were continued until the patient could void urine spontaneously. The levels of analgesia and of motor blockade were recorded. The urge to void disappeared immediately after injection of the local anesthetics. There was no difference in the duration of lower extremity motor blockade between bupivacaine and lidocaine. Detrusor blockade lasted significantly longer in the bupivacaine group (means +/- SD, 460 +/- 60 min) than in the lidocaine group (235 +/- 30 min). Total fluid intake and urine volume accumulated during the detrusor blockade were significantly higher in the bupivacaine group than in the lidocaine group. In the bupivacaine group, the total volume of accumulated urine (875 +/- 385 ml) was also significantly higher than cystometric bladder capacity (505 +/- 120 ml) with the risk of over distension of the bladder. Spontaneous voiding of urine did not occur until segmental sensory analgesia had regressed to the third sacral segment. Spinal anesthesia with lidocaine and with bupivacaine causes a clinically significant disturbance of bladder function due to interruption of the micturition reflex. The urge to void disappears quickly and bladder function remains impaired until the block has regressed to the third sacral segment in all patients. With long-acting local anesthetics, the volume of accumulated urine may exceed the cystometric bladder capacity. With respect to recovery of urinary bladder function, the use of short-acting local anesthetics for spinal anesthesia seems to be preferable.

Simulation of Initiation in Hexanitrostilbene

NASA Astrophysics Data System (ADS)

Thompson, Aidan; Shan, Tzu-Ray; Yarrington, Cole; Wixom, Ryan

We report on the effect of isolated voids and pairs of nearby voids on hot spot formation, growth and chemical reaction initiation in hexanitrostilbene (HNS) crystals subjected to shock loading. Large-scale, reactive molecular dynamics simulations are performed using the reactive force field (ReaxFF) as implemented in the LAMMPS software. The ReaxFF force field description for HNS has been validated previously by comparing the isothermal equation of state to available diamond anvil cell (DAC) measurements and density function theory (DFT) calculations. Micron-scale molecular dynamics simulations of a supported shockwave propagating in HNS crystal along the [010] orientation are performed (up = 1.25 km/s, Us =4.0 km/s, P = 11GPa.) We compare the effect on hot spot formation and growth rate of isolated cylindrical voids up to 0.1 µm in size with that of two 50nm voids set 100nm apart. Results from the micron-scale atomistic simulations are compared with hydrodynamics simulations. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lock- heed Martin Corporation, for the U.S. DOE National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Predictors of early postoperative voiding dysfunction and other complications following a midurethral sling.

PubMed

Ripperda, Christopher M; Kowalski, Joseph T; Chaudhry, Zaid Q; Mahal, Aman S; Lanzer, Jennifer; Noor, Nabila; Good, Meadow M; Hynan, Linda S; Jeppson, Peter C; Rahn, David D

2016-11-01

The rates reported for postoperative urinary retention following midurethral sling procedures are highly variable. Determining which patients have a higher likelihood of failing a voiding trial will help with preoperative counseling prior to a midurethral sling. The objective of the study was to identify preoperative predictors for failed voiding trial following an isolated midurethral sling. A retrospective, multicenter, case-control study was performed by including all isolated midurethral sling procedures performed between Jan. 1, 2010 to June 30, 2015, at 6 academic centers. We collected demographics, medical and surgical histories, voiding symptoms, urodynamic evaluation, and intraoperative data from the medical record. We excluded patients not eligible for attempted voiding trial after surgery (eg, bladder perforation requiring catheterization). Cases failed a postoperative voiding trial and were discharged with an indwelling catheter or taught intermittent self-catheterization; controls passed a voiding trial. We also recorded any adverse events such as urinary tract infection or voiding dysfunction up to 6 weeks after surgery. Bivariate analyses were completed using Mann-Whitney and Pearson χ 2 tests as appropriate. Multivariable stepwise logistic regression was used to determine predictors of failing a voiding trial. A total of 464 patients had an isolated sling (70.9% retropubic, 28.4% transobturator, 0.6% single incision); 101 (21.8%) failed the initial voiding trial. At follow-up visits, 90.4% passed a second voiding trial, and 38.5% of the remainder passed on the third attempt. For the bivariate analyses, prior prolapse or incontinence surgery was similar in cases vs controls (31% vs 28%, P = .610) as were age, race, body mass index, and operative time. Significantly more of the cases (32%) than controls (22%) had a Charlson comorbidity index score of 1 or greater (P = .039). Overactive bladder symptoms of urgency, frequency, and urgency incontinence were similar in both groups as was detrusor overactivity in those with a urodynamic evaluation (29% vs 22%, P = .136), but nocturia was reported more in the cases (50% vs 38%, P = .046). Mean (SD) bladder capacity was similar in both groups (406 [148] mL vs 388 [122] mL, P = .542) as was maximum flow rate with uroflowmetry and pressure flow studies. Cases were significantly more likely to have a voiding type other than detrusor contraction: 37% vs 25%, P = .027, odds ratio, 1.79 (95% confidence interval, 1.07-3.00). There was no difference in voiding trial failures between retropubic and transobturator routes (23.1% vs 18.9%, P = .329). Within 6 weeks of surgery, the frequency of urinary tract infection in cases was greater than controls (20% vs 6%, P < .001; odds ratio, 3.51 [95% confidence interval, 1.82-6.75]). After passing a repeat voiding trial, cases were more likely to present with acute urinary retention (10% vs 3%, P = .003; odds ratio, 4.00 [95% confidence interval, 1.61-9.92]). For multivariable analyses, increasing Charlson comorbidity index increased the risk of a voiding trial failure; apart from this, we did not identify other demographic information among the patients who did not undergo urodynamic evaluation that reliably forecasted a voiding trial failure. The majority of women will pass a voiding trial on the first attempt after an isolated midurethral sling. Current medical comorbidities are predictive of a voiding trial failure, whereas other demographic/examination findings are not. Patients failing the initial voiding trial are at an increased risk of postoperative urinary tract infection or developing acute retention after passing a subsequent voiding trial. Copyright © 2016 Elsevier Inc. All rights reserved.

Electromigration of intergranular voids in metal films for microelectronic interconnects

NASA Astrophysics Data System (ADS)

Averbuch, Amir; Israeli, Moshe; Ravve, Igor

2003-04-01

Voids and cracks often occur in the interconnect lines of microelectronic devices. They increase the resistance of the circuits and may even lead to a fatal failure. Voids may occur inside a single grain, but often they appear on the boundary between two grains. In this work, we model and analyze numerically the migration and evolution of an intergranular void subjected to surface diffusion forces and external voltage applied to the interconnect. The grain-void interface is considered one-dimensional, and the physical formulation of the electromigration and diffusion model results in two coupled fourth-order one-dimensional time-dependent PDEs. The boundary conditions are specified at the triple points, which are common to both neighboring grains and the void. The solution of these equations uses a finite difference scheme in space and a Runge-Kutta integration scheme in time, and is also coupled to the solution of a static Laplace equation describing the voltage distribution throughout the grain. Since the voltage distribution is required only along the interface line, the two-dimensional discretization of the grain interior is not needed, and the static problem is solved by the boundary element method at each time step. The motion of the intergranular void was studied for different ratios between the diffusion and the electric field forces, and for different initial configurations of the void.

Simulation-aided constitutive law development - Assessment of low triaxiality void nucleation models via extended finite element method

NASA Astrophysics Data System (ADS)

Zhao, Jifeng; Kontsevoi, Oleg Y.; Xiong, Wei; Smith, Jacob

2017-05-01

In this work, a multi-scale computational framework has been established in order to investigate, refine and validate constitutive behaviors in the context of the Gurson-Tvergaard-Needleman (GTN) void mechanics model. The eXtended Finite Element Method (XFEM) has been implemented in order to (1) develop statistical volume elements (SVE) of a matrix material with subscale inclusions and (2) to simulate the multi-void nucleation process due to interface debonding between the matrix and particle phases. Our analyses strongly suggest that under low stress triaxiality the nucleation rate of the voids f˙ can be well described by a normal distribution function with respect to the matrix equivalent stress (σe), as opposed to that proposed (σbar + 1 / 3σkk) in the original form of the single void GTN model. The modified form of the multi-void nucleation model has been validated based on a series of numerical experiments with different loading conditions, material properties, particle shape/size and spatial distributions. The utilization of XFEM allows for an invariant finite element mesh to represent varying microstructures, which implies suitability for drastically reducing complexity in generating the finite element discretizations for large stochastic arrays of microstructure configurations. The modified form of the multi-void nucleation model is further applied to study high strength steels by incorporating first principles calculations. The necessity of using a phenomenological interface separation law has been fully eliminated and replaced by the physics-based cohesive relationship obtained from Density Functional Theory (DFT) calculations in order to provide an accurate macroscopic material response.

In situ imaging of the soldering reactions in nanoscale Cu/Sn/Cu and Sn/Cu/Sn diffusion couples

NASA Astrophysics Data System (ADS)

Yin, Qiyue; Gao, Fan; Gu, Zhiyong; Wang, Jirui; Stach, Eric A.; Zhou, Guangwen

2018-01-01

The soldering reactions of three-segmented Sn/Cu/Sn and Cu/Sn/Cu diffusion couples are monitored by in-situ transmission electron microscopy to reveal the metallurgical reaction mechanism and the associated phase transformation pathway. For Sn/Cu/Sn diffusion couples, there is no ɛ-Cu3Sn formation due to the relatively insufficient Cu as compared to Sn. Kirkendall voids form initially in the Cu segment and then disappear due to the volume expansion associated with the continued intermetallic compound (IMC) formation as the reaction progresses. The incoming Sn atoms react with Cu to form η-Cu6Sn5, and the continuous reaction then transforms the entire nanowire to η-Cu6Sn5 grains with remaining Sn. With continued heating slightly above the melting point of Sn, an Sn-rich liquid phase forms between η-Cu6Sn5 grains. By contrast, the reaction in the Cu/Sn/Cu diffusion couples results in the intermetallic phases of both Cu3Sn and Cu6Sn5 and the development of Cu6Sn5 bulges on Cu3Sn grains. Kirkendall voids form in the two Cu segments, which grow and eventually break the nanowire into multiple segments.

Biodegradable braided poly(lactic-co-glycolic acid) urethral stent combined with dutasteride in the treatment of acute urinary retention due to benign prostatic enlargement: a pilot study.

PubMed

Kotsar, Andres; Isotalo, Taina; Juuti, Hanne; Mikkonen, Joonas; Leppiniemi, Jenni; Hänninen, Venla; Kellomäki, Minna; Talja, Martti; Tammela, Teuvo L J

2009-03-01

To evaluate, in a pilot study, the efficacy and safety of combining a braided poly(lactic-co-glycolic acid) (PLGA, a copolymer of l-lactide and glycolide) urethral stent and dutasteride in the treatment of acute urinary retention (AUR) due to benign prostatic enlargement (BPE). Ten men with AUR due to BPE were treated as outpatients. A biodegradable braided PLGA urethral stent was inserted into the prostatic urethra, using a specially designed insertion device under visual control. Dutasteride treatment was started and the patients were followed up for 3 months after insertion of the stents. In all patients the stents were placed successfully with the new insertion device. All men were able to void after inserting the stent. At 1 month five patients voided freely with a low residual urine volume (<150 mL), two voided but had a high residual urine volume and a suprapubic catheter was placed, and three needed a suprapubic or an indwelling catheter before 1 month, due to AUR or comorbidities. At 3 months five patients were voiding with no problems. We have developed a new and effective insertion device for biodegradable braided prostatic stents. The new braided-pattern stent overcomes the earlier problems of migration and sudden breakage into large particles associated with biodegradable spiral stents. However, the mechanical properties of the new stent need to be improved and tested in a longer follow-up. We consider that this new biodegradable braided-pattern urethral stent could provide a new option in the future treatment of AUR.

Trpm7 Protein Contributes to Intercellular Junction Formation in Mouse Urothelium*

PubMed Central

Watanabe, Masaki; Suzuki, Yoshiro; Uchida, Kunitoshi; Miyazaki, Naoyuki; Murata, Kazuyoshi; Matsumoto, Seiji; Kakizaki, Hidehiro; Tominaga, Makoto

2015-01-01

Trpm7 is a divalent cation-permeable channel that has been reported to be involved in magnesium homeostasis as well as cellular adhesion and migration. We generated urothelium-specific Trpm7 knock-out (KO) mice to reveal the function of Trpm7 in vivo. A Trpm7 KO was induced by tamoxifen and was confirmed by genomic PCR and immunohistochemistry. By using patch clamp recordings in primary urothelial cells, we observed that Mg2+-inhibitable cation currents as well as acid-inducible currents were significantly smaller in Trpm7 KO urothelial cells than in cells from control mice. Assessment of voiding behavior indicated a significantly smaller voided volume in Trpm7 KO mice (mean voided volume 0.28 ± 0.08 g in KO mice and 0.36 ± 0.04 g in control mice, p < 0.05, n = 6–8). Histological analysis showed partial but substantial edema in the submucosal layer of Trpm7 KO mice, most likely due to inflammation. The expression of proinflammatory cytokines TNF-α and IL-1β was significantly higher in Trpm7 KO bladders than in controls. In transmission electron microscopic analysis, immature intercellular junctions were observed in Trpm7 KO urothelium but not in control mice. These results suggest that Trpm7 is involved in the formation of intercellular junctions in mouse urothelium. Immature intercellular junctions in Trpm7 knock-out mice might lead to a disruption of barrier function resulting in inflammation and hypersensitive bladder afferent nerves that may affect voiding behavior in vivo. PMID:26504086

Trpm7 Protein Contributes to Intercellular Junction Formation in Mouse Urothelium.

PubMed

Watanabe, Masaki; Suzuki, Yoshiro; Uchida, Kunitoshi; Miyazaki, Naoyuki; Murata, Kazuyoshi; Matsumoto, Seiji; Kakizaki, Hidehiro; Tominaga, Makoto

2015-12-11

Trpm7 is a divalent cation-permeable channel that has been reported to be involved in magnesium homeostasis as well as cellular adhesion and migration. We generated urothelium-specific Trpm7 knock-out (KO) mice to reveal the function of Trpm7 in vivo. A Trpm7 KO was induced by tamoxifen and was confirmed by genomic PCR and immunohistochemistry. By using patch clamp recordings in primary urothelial cells, we observed that Mg(2+)-inhibitable cation currents as well as acid-inducible currents were significantly smaller in Trpm7 KO urothelial cells than in cells from control mice. Assessment of voiding behavior indicated a significantly smaller voided volume in Trpm7 KO mice (mean voided volume 0.28 ± 0.08 g in KO mice and 0.36 ± 0.04 g in control mice, p < 0.05, n = 6-8). Histological analysis showed partial but substantial edema in the submucosal layer of Trpm7 KO mice, most likely due to inflammation. The expression of proinflammatory cytokines TNF-α and IL-1β was significantly higher in Trpm7 KO bladders than in controls. In transmission electron microscopic analysis, immature intercellular junctions were observed in Trpm7 KO urothelium but not in control mice. These results suggest that Trpm7 is involved in the formation of intercellular junctions in mouse urothelium. Immature intercellular junctions in Trpm7 knock-out mice might lead to a disruption of barrier function resulting in inflammation and hypersensitive bladder afferent nerves that may affect voiding behavior in vivo. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Chemical Method of Urine Volume Measurement

NASA Technical Reports Server (NTRS)

Petrack, P.

1967-01-01

A system has been developed and qualified as flight hardware for the measurement of micturition volumes voided by crewmen during Gemini missions. This Chemical Urine Volume Measurement System (CUVMS) is used for obtaining samples of each micturition for post-flight volume determination and laboratory analysis for chemical constituents of physiological interest. The system is versatile with respect to volumes measured, with a capacity beyond the largest micturition expected to be encountered, and with respect to mission duration of inherently indefinite length. The urine sample is used for the measurement of total micturition volume by a tracer dilution technique, in which a fixed, predetermined amount of tritiated water is introduced and mixed into the voided urine, and the resulting concentration of the tracer in the sample is determined with a liquid scintillation spectrometer. The tracer employed does not interfere with the analysis for the chemical constituents of the urine. The CUVMS hardware consists of a four-way selector valve in which an automatically operated tracer metering pump is incorporated, a collection/mixing bag, and tracer storage accumulators. The assembled system interfaces with a urine receiver at the selector valve inlet, sample bags which connect to the side of the selector valve, and a flexible hose which carries the excess urine to the overboard drain connection. Results of testing have demonstrated system volume measurement accuracy within the specification limits of +/-5%, and operating reliability suitable for system use aboard the GT-7 mission, in which it was first used.

Use of the Steinberg and Carroll-Holt model concepts in ductile fracture

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

Seaman, L.; Boustie, M.; Resseguier, T. de

1998-07-10

We have extended the SRI ductile fracture model (DFRACT) for spall behavior of aluminum and copper. The temperature computation procedure, thermal strength reduction function, work hardening, and Bauschinger effects from the Steinberg model were added. The threshold stress for void growth in the DFRACT model was equated to the stress for general yielding in the Carroll-Holt model for porous materials. With these modifications of DFRACT, we simulated a series of earlier impacts in 1145 (commercially pure) aluminum in which partial spall had been reached. The revised model was able to represent the numbers, sizes, and locations of voids through themore » sample. The use of the Carroll-Holt and Steinberg model features allows the DFRACT model to reach larger void volumes in the simulations and therefore to better represent heavy damage.« less

Does sex matter? A matched pairs analysis of neuromodulation outcomes in women and men.

PubMed

Nguyen, Laura N; Bartley, Jamie; Killinger, Kim A; Gupta, Priyanka; Lavin, John; Khourdaji, Ayad; Gilleran, Jason; Gaines, Natalie; Boura, Judith A; Peters, Kenneth M

2018-05-01

To evaluate whether baseline symptoms and outcomes are influenced by gender in a matched cohort undergoing neuromodulation. Patients in our prospective neuromodulation database that had a tined lead placed were reviewed. Those that had implantable pulse generator (IPG) placed were matched on age and urologic diagnosis. History, voiding diaries, satisfaction, Interstitial Cystitis Symptom/Problem Index (ICSIPI), and overactive bladder symptom severity (OABq ss)/health-related quality of life (HRQOL) preimplant and over 3 years were evaluated using descriptive statistics, repeated measures, and matched pair GEE or mixed analyses. Of 590 patients in the database, more women than men received an IPG (450/488; 92.2 vs. 84/102; 82.4%; p = 0.0011). Eighty matched pairs (n = 160; 81% ≥ 50 years old; 56.25% had urgency/frequency with urge incontinence-UI) were identified and evaluated. On voiding diaries, volume/void was greater in women only at baseline (p = 0.040); both groups improved over time (p < 0.0001). Urinary frequency improved in both women and men (p = 0.0010; p = 0.0025). Over 3 years, UI episodes/day improved only in men (p = 0.017) and UI severity improved only in women (p < 0.0001). ICSIPI, OABq ss, and HRQOL scores improved similarly in both groups (p < 0.0001 for all measures in both groups), and although more women were satisfied at 3 months (p = 0.027), groups did not differ at other time points. More women undergo neuromodulation and have initial success and subsequent IPG implantation. UI episodes improved only in men, and UI severity improved only in women. Both women and men experienced similar levels of symptom improvement on other measures.

Behavior of Aging, Micro-Void, and Self-Healing of Glass/Ceramic Materials and Its Effect on Mechanical Properties

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

Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

This chapter first describes tests to investigate the temporal evolution of the volume fraction of ceramic phases, the evolution of micro-damage, and the self-healing behavior of the glass ceramic sealant used in SOFCs, then a phenomenological model based on mechanical analogs is developed to describe the temperature dependent Young’s modulus of glass ceramic seal materials. It was found that after the initial sintering process, further crystallization of the glass ceramic sealant does not stop, but slows down and reduces the residual glass content while boosting the ceramic crystalline content. Under the long-term operating environment, distinct fibrous and needle-like crystals inmore » the amorphous phase disappeared, and smeared/diffused phase boundaries between the glass phase and ceramic phase were observed. Meanwhile, the micro-damage was induced by the cooling-down process from the operating temperature to the room temperature, which can potentially degrade the mechanical properties of the glass/ceramic sealant. The glass/ceramic sealant self-healed upon reheating to the SOFC operating temperature, which can restore the mechanical performance of the glass/ceramic sealant. The phenomenological model developed here includes the effects of continuing aging and devitrification on the ceramic phase volume fraction and the resulted mechanical properties of glass ceramic seal material are considered. The effects of micro-voids and self-healing are also considered using a continuum damage mechanics (CDM) model. The formulation is for glass/ceramic seal in general, and it can be further developed to account for effects of various processing parameters. This model was applied to G18, and the temperature-dependent experimental measurements were used to calibrate the modeling parameters and to validate the model prediction.« less

Fractographic correlations with mechanical properties in ferritic martensitic steels

NASA Astrophysics Data System (ADS)

Das, Arpan; Chakravartty, Jayanta Kumar

2017-12-01

The ultimate continuum of a material is nothing but the process called fracture. Fracture surface retains the imprint of the entire deformation history undergone in a material. Hence, it is possible to derive the approximate deformation and fracture properties of a material from a systematic fracture feature analysis. There has been large volume of literature available in the open domain correlating different mechanical and fracture responses of reduced activation ferritic martensitic grade steels under various testing conditions/circumstances with corresponding microstructural interpretation. There has been no such literature available to establish the relationship between the two-dimensional fracture geometry/topography with its corresponding deformation and mechanical properties of the material as a function of testing temperature, which has been the primary aim in the current investigation. A comprehensive literature survey has been carried out to realize this fact. In order to establish the above hypothesis, many tensile experiments were carried out at constant strain rate by systematic variation of the test temperature. The initial void volume fraction or the inclusion content of material was kept unaltered and the test temperature has been varied orderly on different multiple specimens to vary the deformation-induced nucleation sites of micro voids (i.e. different carbides, phase interfaces, dislocation pile up etc), which results in a change of fracture topography under uniaxial tensile deformation. A conventional metallographic technique followed by optical microscopy has been employed to understand the basic morphologies and characteristics of the alloy exposed at different temperatures. Fractographic investigation of the broken tensile specimens at various temperatures is carried out to measure the fracture features by using quantitative fractography on representative scanning electron fractographs through image processing.

Study on process and characterization of high-temperature resistance polyimide composite

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

Pan, Ling-Ying; Zhao, Wei-Dong; Liu, Han-Yang

2016-05-18

A novel polyimide composite with upper-use temperature of 420°C was prepared by autoclave process. The thermogravimetic analysis and rheological properties of uncured polyimide resin powders were analyzed. The influences of process parameters and post-treatment process on the properties of composites were also investigated. The morphologies of polyimide composites after shear fracture were observed by scanning electron microscope (SEM). The high-temperature resistance of composite was characterized by dynamic mechanical thermal analyzer (DMTA). Results showed that the imidization reaction mainly occurred in the temperature range of 100°C~220°C, and the largest weight loss rate appearing at 145°C indicated a drastic imidization reaction occurred.more » The melt viscosity of polyimide resin decreased with increasing the temperature between 220°C ∼305°C, and then increased with the increase of temperature due to the molecular crosslinking reactions. The fiber volume contents and void contents could be effectively controlled by applying the pressure step by step. The fiber volume content was sensitive to the initial pressure (P{sub i}) during the imidization. The second-stage pressure (P{sub 2}) and the temperature for applying the P{sub 2} (T{sub 2}) during the imidization had a great effect on the void content of composite. Good mechanical properties and interfacial adhesion of polyimide composite could obtain by optimized process. The post-treatment process can obviously increase the high-temperature resistance of polyimide composite. The polyimide composite treated at 420°C exhibited good retention of mechanical properties at 420°C and had a glass transition temperature (Tg) of 456°C. The retentions of flexible strength, flexible modulus and short beam shear strength of polyimide composite at 420°C were 65%, 84% and 62% respectively.« less

Effect of Microgravity on Material Undergoing Melting and Freezing: the TES Experiment

NASA Technical Reports Server (NTRS)

Namkoong, David; Jacqmin, David; Szaniszlo, Andrew

1995-01-01

This experiment is the first to melt and freeze a high temperature thermal energy storage (TES) material under an extended duration of microgravity. It is one of a series to validate an analytical computer program that predicts void behavior of substances undergoing phase change under microgravity. Two flight experiments were launched in STS-62. The first, TES-1, containing lithium fluoride in an annular volume, performed flawlessly in the 22 hours of its operation. Results are reported in this paper. A software failure in TES-2 caused its shutdown after 4 seconds. A computer program, TESSIM, for thermal energy storage simulation is being developed to analyze the phenomena occurring within the TES containment vessel. The first order effects, particularly the surface tension forces, have been incorporated into TESSIM. TESSIM validation is based on two types of results. First is the temperature history of various points of the containment structure, and second, upon return from flight, the distribution of the TES material within the containment vessel following the last freeze cycle. The temperature data over the four cycles showed a repetition of results over the third and fourth cycles. This result is a confirmation that any initial conditions prior to the first cycle had been damped out by the third cycle. The TESSIM simulation showed a close comparison with the flight data. The solidified TES material distribution within the containment vessel was obtained by a tomography imaging process. The frozen material was concentrated toward the colder end of the annular volume. The TESSIM prediction showed the same pattern. With the general agreement of TESSIM and the data, a computerized visual representation can be shown which accurately shows the movement and behavior of the void during the entire freezing and melting cycles.

Effect of microgravity on material undergoing melting and freezing: The TES Experiment

NASA Astrophysics Data System (ADS)

Namkoong, David; Jacqmin, David; Szaniszlo, Andrew

1995-01-01

This experiment is the first to melt and freeze a high temperature thermal energy storage (TES) material under an extended duration of microgravity. It is one of a series to validate an analytical computer program that predicts void behavior of substances undergoing phase change under microgravity. Two flight experiments were launched in STS-62. The first, TES-1, containing lithium fluoride in an annular volume, performed flawlessly in the 22 hours of its operation. Results are reported in this paper. A software failure in TES-2 caused its shutdown after 4 seconds. A computer program, TESSIM, for thermal energy storage simulation is being developed to analyze the phenomena occurring within the TES containment vessel. The first order effects, particularly the surface tension forces, have been incorporated into TESSIM. TESSIM validation is based on two types of results. First is the temperature history of various points of the containment structure, and second, upon return from flight, the distribution of the TES material within the containment vessel following the last freeze cycle. The temperature data over the four cycles showed a repetition of results over the third and fourth cycles. This result is a confirmation that any initial conditions prior to the first cycle had been damped out by the third cycle. The TESSIM simulation showed a close comparison with the flight data. The solidified TES material distribution within the containment vessel was obtained by a tomography imaging process. The frozen material was concentrated toward the colder end of the annular volume. The TESSIM prediction showed the same pattern. With the general agreement of TESSIM and the data, a computerized visual representation can be shown which accurately shows the movement and behavior of the void during the entire freezing and melting cycles.

Saw palmetto (Serenoa repens) in men with lower urinary tract symptoms: effects on urodynamic parameters and voiding symptoms.

PubMed

Gerber, G S; Zagaja, G P; Bales, G T; Chodak, G W; Contreras, B A

1998-06-01

To assess the effects of saw palmetto on voiding symptoms and urodynamic parameters in men with lower urinary tract symptoms (LUTS) presumed secondary to benign prostatic hyperplasia (BPH). Fifty men with previously untreated LUTS and a minimum International Prostate Symptom Score (IPSS) of 10 or greater were treated with a commercially available form of saw palmetto (160 mg twice per day) for 6 months. The initial evaluation included measurement of peak urinary flow rate, postvoid residual urine volume, pressure-flow study, and serum prostate-specific antigen (PSA) level. Patients completed an IPSS, serum PSA was determined, and flow rate was measured every 2 months during the course of the study. A urodynamic evaluation was repeated at the completion of the 6-month trial. The mean IPSS (+/-SD) improved from 19.5+/-5.5 to 12.5+/-7.0 (P <0.001) among the 46 men who completed the study. Significant improvement in the symptom score was noted after treatment with saw palmetto for 2 months. An improvement in symptom score of 50% or greater after treatment with saw palmetto for 2, 4, and 6 months was noted in 21% (10 of 48), 30% (14 of 47), and 46% (21 of 46) of patients, respectively. There was no significant change in peak urinary flow rate, postvoid residual urine volume, or detrusor pressure at peak flow among patients completing the study. No significant change in mean serum PSA level was noted. Saw palmetto is a well-tolerated agent that may significantly improve lower urinary tract symptoms in men with BPH. However, we were unable to demonstrate any significant improvement in objective measures of bladder outlet obstruction. Placebo-controlled trials of saw palmetto are needed to evaluate the true effectiveness of this compound.

Modeling the effects of biomass accumulation on the performance of a biotrickling filter packed with PUF support for the alkaline biotreatment of dimethyl disulfide vapors in air.

PubMed

Arellano-García, Luis; Dorado, Antonio D; Morales-Guadarrama, Axayacatl; Sacristan, Emilio; Gamisans, Xavier; Revah, Sergio

2015-01-01

Excess biomass buildup in biotrickling filters leads to low performance. The effect of biomass accumulation in a biotrickling filter (BTF) packed with polyurethane foam (PUF) was assessed in terms of hydrodynamics and void space availability in a system treating dimethyl disulfide (DMDS) vapors with an alkaliphilic consortium. A sample of colonized support from a BTF having been operating for over a year was analyzed, and it was found that the BTF void bed fraction was reduced to almost half of that calculated initially without biomass. Liquid flow through the examined BTF yielded dispersion coefficient values of 0.30 and 0.72 m(2) h(-1), for clean or colonized PUF, respectively. 3D images of attached biomass obtained with magnetic resonance imaging allowed to calculate the superficial area and the biofilm volume percentage and depth as 650 m(2) m(-3), 35%, and 0.6 mm respectively. A simplified geometric approximation of the complex PUF structure was proposed using an orthogonal 3D mesh that predicted 600 m(2) m(-3) for the same biomass content. With this simplified model, it is suggested that the optimum biomass content would be around 20% of bed volume. The activity of the microorganisms was evaluated by respirometry and the kinetics represented with a Haldane equation type. Experimentally determined parameters were used in a mathematical model to simulate the DMDS elimination capacity (EC), and better description was found when the removal experimental data were matched with a model including liquid axial dispersion in contrast to an ideal plug flow model.

Effects of long-term androgen replacement therapy on the physical and mental statuses of aging males with late-onset hypogonadism: a multicenter, randomized controlled trial in Japan (EARTH Study)

PubMed Central

Konaka, Hiroyuki; Sugimoto, Kazuhiro; Orikasa, Hideki; Iwamoto, Teruaki; Takamura, Toshinari; Takeda, Yoshiyu; Shigehara, Kazuyoshi; Iijima, Masashi; Koh, Eitetsu; Namiki, Mikio

2016-01-01

Androgen replacement therapy (ART) efficacy on late-onset hypogonadism (LOH) has been widely investigated in Western countries; however, it remains controversial whether ART can improve health and prolong active lifestyles. We prospectively assessed long-term ART effects on the physical and mental statuses of aging men with LOH in Japan. The primary endpoint was health-related quality of life assessed by questionnaires. Secondary endpoints included glycemic control, lipid parameters, blood pressure, waist circumference, body composition, muscular strength, International Prostate Symptom Scores (IPSS), International Index of Erectile Function-5 (IIEF-5) scores, and serum prostate-specific antigen levels. Of the 1637 eligible volunteers, 334 patients > 40 years with LOH were randomly assigned to either the ART (n = 169) or control groups (n = 165). Fifty-two weeks after the initial treatment, ART significantly affected the role physical subdomain of the short form-36 health survey (SF-36) scale (P = 0.0318). ART was also associated with significant decreases in waist circumstance (P = 0.002) and serum triglyceride (TG) (P = 0.013) and with significant increases in whole-body and leg muscle mass volumes (P = 0.071 and 0.0108, respectively), serum hemoglobin (P < 0.001), IPSS voiding subscore (P = 0.0418), and the second question on IIEF-5 (P = 0.0049). There was no significant difference between the groups in terms of severe adverse events. In conclusion, in patients with LOH, long-term ART exerted beneficial effects on Role Physical subdomain of the SF-36 scale, serum TG, waist circumstance, muscle mass volume, voiding subscore of IPSS, and the second question of IIEF-5. We hope our study will contribute to the future development of this area. PMID:25761833

Evaluation of self-consolidating concrete.

DOT National Transportation Integrated Search

2003-01-01

Conventional concrete tends to present a problem with regard to adequate consolidation in thin sections or areas of congested reinforcement, which leads to a large volume of entrapped air voids and compromises the strength and durability of the concr...

Post-void residual urinary volume is an independent predictor of biopsy results in men at risk for prostate cancer.

PubMed

Cormio, Luigi; Lucarelli, Giuseppe; Netti, Giuseppe Stefano; Stallone, Giovanni; Selvaggio, Oscar; Troiano, Francesco; Di Fino, Giuseppe; Sanguedolce, Francesca; Bufo, Pantaleo; Grandaliano, Giuseppe; Carrieri, Giuseppe

2015-04-01

to determine whether peak flow rate (PFR) and post-void residual urinary volume (PVRUV) predict prostate biopsy outcome. The study population consisted of 1780 patients undergoing first prostate biopsy. Patients with prostate cancer (PCa) had significantly greater prostate-specific antigen (PSA) and PFR but lower prostate volume (PVol) and PVRUV than those without PCa. Receiver operator characteristic curve analysis showed that PVol and PVRUV were the most accurate predictors of biopsy outcome. The addition of PVRUV to the multivariate logistic regression model based on standard clinical parameters (age, PSA, digital rectal examination, PVol) significantly increased the predictive accuracy of the model in both the population overall (79% vs. 77%; p=0.001) and patients with PSA levels up to 10 ng/ml (74.3% vs. 71.7%; p=0.005). PVRUV seems to be an accurate non-invasive test to predict biopsy outcome that can be used alone or in combination with PVol in the decision-making process for men potentially facing a prostate biopsy. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Experimental and Computational Investigations of Phase Change Thermal Energy Storage Canisters

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir; Kerslake, Thomas; Sokolov, Pavel; Tolbert, Carol

1996-01-01

Two sets of experimental data are examined in this paper, ground and space experiments, for cylindrical canisters with thermal energy storage applications. A 2-D computational model was developed for unsteady heat transfer (conduction and radiation) with phase-change. The radiation heat transfer employed a finite volume method. The following was found in this study: (1) Ground Experiments: the convection heat transfer is equally important to that of the radiation heat transfer; radiation heat transfer in the liquid is found to be more significant than that in the void; including the radiation heat transfer in the liquid resulted in lower temperatures (about 15 K) and increased the melting time (about 10 min.); generally, most of the heat flow takes place in the radial direction. (2) Space Experiments: radiation heat transfer in the void is found to be more significant than that in the liquid (exactly the opposite to the Ground Experiments); accordingly, the location and size of the void affects the performance considerably; including the radiation heat transfer in the void resulted in lower temperatures (about 40 K).

Topology and geometry of the dark matter web

NASA Astrophysics Data System (ADS)

Ramachandra, Nesar; Shandarin, Sergei

2017-01-01

Topological connections in the single-streaming voids and multi-streaming filaments and walls reveal a cosmic web structure different from traditional mass density fields. A single void structure not only percolates the multi-stream field in all the directions, but also occupies over 99 per cent of all the single-streaming regions. Sub-grid analyses on scales smaller than simulation resolution reveal tiny pockets of voids that are isolated by membranes of the structure. For the multi-streaming excursion sets, the percolating structure is much thinner than the filaments in over-density excursion approach. We also introduce, for the first time, a framework to detect dark matter haloes in multi-stream fields. Closed compact regions hosting local maxima of the multi-stream field are detected using local geometrical conditions and properties of the Lagrangian sub-manifold. All the halo particles are guaranteed to be completely outside void regions of the Universe. Majority of the halo candidates are embedded in the largest structure that percolates the entire volume. The University of Kansas FY 2017 Competition General Research Fund, GRF Award 2301155.

Mobile Sinks Assisted Geographic and Opportunistic Routing Based Interference Avoidance for Underwater Wireless Sensor Network

PubMed Central

Ahmed, Farwa; Wadud, Zahid; Alrajeh, Nabil; Alabed, Mohamad Souheil

2018-01-01

The distinctive features of acoustic communication channel-like high propagation delay, multi-path fading, quick attenuation of acoustic signal, etc. limit the utilization of underwater wireless sensor networks (UWSNs). The immutable selection of forwarder node leads to dramatic death of node resulting in imbalanced energy depletion and void hole creation. To reduce the probability of void occurrence and imbalance energy dissipation, in this paper, we propose mobility assisted geo-opportunistic routing paradigm based on interference avoidance for UWSNs. The network volume is divided into logical small cubes to reduce the interference and to make more informed routing decisions for efficient energy consumption. Additionally, an optimal number of forwarder nodes is elected from each cube based on its proximity with respect to the destination to avoid void occurrence. Moreover, the data packets are recovered from void regions with the help of mobile sinks which also reduce the data traffic on intermediate nodes. Extensive simulations are performed to verify that our proposed work maximizes the network lifetime and packet delivery ratio. PMID:29614794

Mobile Sinks Assisted Geographic and Opportunistic Routing Based Interference Avoidance for Underwater Wireless Sensor Network.

PubMed

Ahmed, Farwa; Wadud, Zahid; Javaid, Nadeem; Alrajeh, Nabil; Alabed, Mohamad Souheil; Qasim, Umar

2018-04-02

The distinctive features of acoustic communication channel-like high propagation delay, multi-path fading, quick attenuation of acoustic signal, etc. limit the utilization of underwater wireless sensor networks (UWSNs). The immutable selection of forwarder node leads to dramatic death of node resulting in imbalanced energy depletion and void hole creation. To reduce the probability of void occurrence and imbalance energy dissipation, in this paper, we propose mobility assisted geo-opportunistic routing paradigm based on interference avoidance for UWSNs. The network volume is divided into logical small cubes to reduce the interference and to make more informed routing decisions for efficient energy consumption. Additionally, an optimal number of forwarder nodes is elected from each cube based on its proximity with respect to the destination to avoid void occurrence. Moreover, the data packets are recovered from void regions with the help of mobile sinks which also reduce the data traffic on intermediate nodes. Extensive simulations are performed to verify that our proposed work maximizes the network lifetime and packet delivery ratio.

Urodynamic measurements reflect physiological bladder function in rats.

PubMed

Schneider, Marc P; Sartori, Andrea M; Tampé, Juliane; Moors, Selina; Engmann, Anne K; Ineichen, Benjamin V; Hofer, Anna-Sophie; Schwab, Martin E; Kessler, Thomas M

2018-04-01

Our objective was to investigate and compare bladder function in rats assessed by metabolic cage and by urodynamic measurements in fully awake animals. Bladder function of female Lewis rats was investigated in naïve animals by metabolic cage at baseline, 14-16 days after bladder catheter and external urethral sphincter electromyography electrode implantation in fully awake animals by urodynamics, and again by metabolic cage. Investigating the same animals (n = 8), voided volume, average flow, and duration of voiding were similar (P > 0.05) in naïve animals measured by metabolic cage and after catheter implantation by urodynamic measurements and by metabolic cage. In naïve animals measured by metabolic cage, voided volumes were significantly different in the light (resting phase) versus the dark (active phase) part of the 24 h cycle (mean difference 0.14 mL, 21%, P = 0.004, n = 27). Lower urinary tract function assessed by metabolic cage or by urodynamic meaurements in fully awake rats was indistinguishable. Thus, catheter implantation did not significantly change physiological bladder function. This shows that urodynamic measurements in awake animals are an appropriate approach to study lower urinary tract function in health and disease in animal models, directly paralleling the human diagnostic procedures. © 2017 Wiley Periodicals, Inc.

Tuning the Shell Number of Multishelled Metal Oxide Hollow Fibers for Optimized Lithium-Ion Storage.

PubMed

Sun, Jin; Lv, Chunxiao; Lv, Fan; Chen, Shuai; Li, Daohao; Guo, Ziqi; Han, Wei; Yang, Dongjiang; Guo, Shaojun

2017-06-27

Searching the long-life transition-metal oxide (TMO)-based materials for future lithium-ion batteries (LIBs) is still a great challenge because of the mechanical strain resulting from volume change of TMO anodes during the lithiation/delithiation process. To well address this challenging issue, we demonstrate a controlled method for making the multishelled TMO hollow microfibers with tunable shell numbers to achieve the optimal void for efficient lithium-ion storage. Such a particularly designed void can lead to a short diffusion distance for fast diffusion of Li + ions and also withstand a large volume variation upon cycling, both of which are the key for high-performance LIBs. Triple-shelled TMO hollow microfibers are a quite stable anode material for LIBs with high reversible capacities (NiO: 698.1 mA h g -1 at 1 A g -1 ; Co 3 O 4 : 940.2 mA h g -1 at 1 A g -1 ; Fe 2 O 3 : 997.8 mA h g -1 at 1 A g -1 ), excellent rate capability, and stability. The present work opens a way for rational design of the void of multiple shells in achieving the stable lithium-ion storage through the biomass conversion strategy.

How sudden is a compelling desire to void? An observational cystometric study on the suddenness of this sensation.

PubMed

De Wachter, Stefan; Wyndaele, Jean-Jacques

2008-04-01

To evaluate whether a compelling desire to void (CDV) is always perceived suddenly, or whether it can result from the gradual build-up of bladder-filling sensations. The pattern of filling sensations was evaluated during standard cystometric bladder filling in 75 patients who complained of urgency and showed detrusor overactivity during cystometry. Cystometric filling ended when a CDV was reported. The 'warning volume' is defined as the difference in volume between the first perception of filling and the volume at CDV. Different patterns of bladder-filling sensations were reported. A CDV occurred suddenly, without a preceding sensation in 13% of the patients, whereas 66% reported at least two normal preceding filling sensations before a CDV. The bladder volume at the CDV was significantly smaller in patients that reported no or just one preceding sensation compared with those that reported the normal pattern of two or three sensations (P < 0.005). The bladder volume at which the first filling perception was reported was not different regardless of whether it was described as a first sensation of filling, a first desire or a CDV (P = 0.42). The warning volumes were not different between patients with one or no standardized filling sensations (P = 0.7), but they were significantly smaller than in patients with two or three filling sensations (P = 0.85). A CDV can occur suddenly if normal filling sensation is disturbed, but also gradually if normal filling sensation is preserved. In cases of disturbed filling sensation, the volume at CDV and the warning volume are significantly lower.

Intravesical PAC1 Receptor Antagonist, PACAP(6–38), Reduces Urinary Bladder Frequency and Pelvic Sensitivity in NGF-OE Mice

PubMed Central

Girard, Beatrice M.; Malley, Susan E.; Mathews, Morgan M.; May, Victor

2017-01-01

Chronic NGF overexpression (OE) in the urothelium, achieved through the use of a highly urothelium-specific uroplakin II promoter, stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency and non-voiding contractions, and referred somatic sensitivity. Additional NGF-mediated pleiotropic changes might contribute to increased voiding frequency and pelvic hypersensitivity in NGF-OE mice such as neuropeptide/receptor systems including PACAP(Adcyap1) and PAC1 receptor (Adcyap1r1). Given the presence of PAC1-immunoreactive fibers and the expression of PAC1 receptor expression in bladder tissues, and PACAP-facilitated detrusor contraction, whether PACAP/receptor signaling contributes to increased voiding frequency and somatic sensitivity was evaluated in NGF-OE mice. Intravesical administration of the PAC1 receptor antagonist, PACAP(6–38) (300 nM), significantly (p ≤ 0.01) increased intercontraction interval (2.0-fold) and void volume (2.5-fold) in NGF-OE mice. Intravesical instillation of PACAP(6–38) also decreased baseline bladder pressure in NGF-OE mice. PACAP(6–38) had no effects on bladder function in WT mice. Intravesical administration of PACAP(6–38) (300 nM) significantly (p ≤ 0.01) reduced pelvic sensitivity in NGF-OE mice but was without effect in WT mice. PACAP/receptor signaling contributes to the increased voiding frequency and pelvic sensitivity observed in NGF-OE mice. PMID:27146136

BetaCavityWeb: a webserver for molecular voids and channels

PubMed Central

Kim, Jae-Kwan; Cho, Youngsong; Lee, Mokwon; Laskowski, Roman A.; Ryu, Seong Eon; Sugihara, Kokichi; Kim, Deok-Soo

2015-01-01

Molecular cavities, which include voids and channels, are critical for molecular function. We present a webserver, BetaCavityWeb, which computes these cavities for a given molecular structure and a given spherical probe, and reports their geometrical properties: volume, boundary area, buried area, etc. The server's algorithms are based on the Voronoi diagram of atoms and its derivative construct: the beta-complex. The correctness of the computed result and computational efficiency are both mathematically guaranteed. BetaCavityWeb is freely accessible at the Voronoi Diagram Research Center (VDRC) (http://voronoi.hanyang.ac.kr/betacavityweb). PMID:25904629

Seasonal Changes in Lower Urinary Tract Symptoms in Japanese Men With Benign Prostatic Hyperplasia Treated With α1-Blockers

PubMed Central

2017-01-01

Purpose To investigate whether seasonal changes occurred in lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH). Methods Patients aged 50 years and older with BPH treated with α1-blockers were enrolled. The International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum and average flow rate, voided volume, and postvoid residual volume were measured in summer and winter. Results A total of 164 patients were enrolled. The total IPSS and QoL index did not show a significant difference between the 2 seasons. When the IPSS was divided into storage symptoms and voiding symptoms, storage symptoms in winter were substantially but nonsignificantly higher than those in summer (P=0.056). Of the 7 individual symptoms in the IPSS, a significant seasonal difference was observed only for nocturia, with a higher score in winter. Moreover, none of the uroflowmetric parameters showed a seasonal change. Voided volume had significant correlations with each symptom (urgency and nocturia) and overall subjective scores (storage, total IPSS, and QoL) exclusively in summer, while this correlation remained only for nocturia in winter. Conclusions As it has generally been assumed that LUTS deteriorate in winter, the present study corroborated that the severity of storage symptoms was higher in winter than in summer, even in patients treated with α1-blockers. In contrast, a seasonal difference was not observed in the uroflowmetric parameters, which may be partly due to the loss of the correlation between subjective and objective measurements of storage symptoms in winter. PMID:28954461

Cracking evolution behaviors of lightweight materials based on in situ synchrotron X-ray tomography: A review

NASA Astrophysics Data System (ADS)

Luo, Y.; Wu, S. C.; Hu, Y. N.; Fu, Y. N.

2018-03-01

Damage accumulation and failure behaviors are crucial concerns during the design and service of a critical component, leading researchers and engineers to thoroughly identifying the crack evolution. Third-generation synchrotron radiation X-ray computed microtomography can be used to detect the inner damage evolution of a large-density material or component. This paper provides a brief review of studying the crack initiation and propagation inside lightweight materials with advanced synchrotron three-dimensional (3D) X-ray imaging, such as aluminum materials. Various damage modes under both static and dynamic loading are elucidated for pure aluminum, aluminum alloy matrix, aluminum alloy metal matrix composite, and aluminum alloy welded joint. For aluminum alloy matrix, metallurgical defects (porosity, void, inclusion, precipitate, etc.) or artificial defects (notch, scratch, pit, etc.) strongly affect the crack initiation and propagation. For aluminum alloy metal matrix composites, the fracture occurs either from the particle debonding or voids at the particle/matrix interface, and the void evolution is closely related with fatigued cycles. For the hybrid laser welded aluminum alloy, fatigue cracks usually initiate from gas pores located at the surface or sub-surface and gradually propagate to a quarter ellipse or a typical semi-ellipse profile.

Experimental studies of compaction and dilatancy during frictional sliding on faults containing gouge

USGS Publications Warehouse

Morrow, C.A.; Byerlee, J.D.

1989-01-01

Transient strength changes are observed in fault gouge materials when the velocity of shearing is varied. A transient stress peak is produced when the strain rate in the gouge is suddenly increased, whereas a transient stress drop results from a sudden change to a slower strain rate. We have studied the mechanism responsible for these observations by performing frictional sliding experiments on sawcut granite samples filled with a layer of several different fault gouge types. Changes in pore volume and strength were monitored as the sliding velocity alternated between fast and slow rates. Pore volume increased at the faster strain rate, indicating a dilation of the gouge layer, whereas volume decreased at the slower rate indicating compaction. These results verify that gouge dilation is a function of strain rate. Pore volume changed until an equilibrium void ratio of the granular material was reached for a particular rate of strain. Using arguments from soil mechanics, we find that the dense gouge was initially overconsolidated relative to the equilibrium level, whereas the loose gouge was initially underconsolidated relative to this level. Therefore, the transient stress behavior must be due to the overconsolidated state of the gouge at the new rate when the velocity is increased and to the underconsolidated state when the velocity is lowered. Time-dependent compaction was also shown to cause a transient stress response similar to the velocity-dependent behavior. This may be important in natural fault gouges as they become consolidated and stronger with time. In addition, the strain hardening of the gouge during shearing was found to be a function of velocity, rendering it difficult to quantify the change in equilibrium shear stress when velocity is varied under certain conditions. ?? 1989.

Porosity Evolution in a Creeping Single Crystal (Preprint)

DTIC Science & Technology

2012-08-01

1] indicated that the growth of initially present processing induced voids in a nickel based single crystal superalloy played a significant role in...processing induced voids in a nickel based single crystal superalloy played a significant role in limiting creep life. Also, creep tests on single...experimental observations of creep deformation and failure of a nickel based single crystal superalloy, [1, 2]. Metallographic observations have shown that Ni

Defense Standardization Program Journal. January-March 2012

DTIC Science & Technology

2012-03-01

tanks and voids with solvent-based epoxy coatings, ap- plied with varying levels of process control. Because the coatings tended to fail initially at...solids (UHS) epoxy resins and contained no added solvent. In addition, the coat- dsp.dla.mil ings contained thixotropes to counter the tendency of...standardized materials, using universal application processes, to all ballast tanks, fuel tanks, and voids, on all Navy ship classes, including submarines

Atomistic simulations of shock-induced alloying reactions in Ni /Al nanolaminates

NASA Astrophysics Data System (ADS)

Zhao, Shijin; Germann, Timothy C.; Strachan, Alejandro

2006-10-01

We employ molecular dynamics simulations with a first principles-based many body potential to characterize the exothermic alloying reactions of nanostructured Ni /Al multilayers induced by shock loading. We introduce a novel technique that captures both the initial shock transit as well as the subsequent longer-time-scale Ni3Al alloy formation. Initially, the softer Al layers are shock heated to a higher temperature than the harder Ni layers as a result of a series of shock reflections from the impedance-mismatched interfaces. Once initiated, the highly exothermic alloying reactions can propagate in a self-sustained manner by mass and thermal diffusion. We also characterize the role of voids on the initiation of alloying. The interaction of the shock wave with the voids leads not only to significant local heating (hot spots) but also directly aids the intermixing between Al and Ni; both of these phenomena contribute to a significant acceleration of the alloying reactions.

Examination of ductile spall failure through direct numerical simulation

NASA Astrophysics Data System (ADS)

Becker, Richard

2017-06-01

Direct numerical simulation is used to examine the growth and coalescence of a random population of voids leading to spall failure. Void nucleating particles are explicitly represented in the initial geometry, and the arbitrary Lagrange-Eulerian finite element code tracks the void evolution to create the spall surface. The flow fields capture strain localization associated with void interaction at low porosities and ligament necking at final coalescence. Simulations are run to assess the influence of material strain hardening and strain rate sensitivity on void growth and coalescence. These analyses also provide the evolution of longitudinal stress and the energy dissipated, and they reveal a length scale associated with the spall. Additional calculations are performed to examine the influence of loading pulse shape on spall behavior for triangular shaped pressure loading. A dependence of spall scab thickness on pulse shape is determined. These results show localization delayed until porosities reach a few percent and they demonstrate a consistent stress versus porosity relation. The simulations also provide a direct correlation between the spall stress history and the free surface velocity, which can aid in understanding stress corrections applied to experimental data.

Characterization of silodosin and naftopidil in the treatment of bladder dysfunction in the spontaneously hypertensive rat.

PubMed

Saito, Motoaki; Shimizu, Shogo; Ohmasa, Fumiya; Oikawa, Ryo; Tsounapi, Panagiota; Dimitriadis, Fotios; Kinoshita, Yukako; Satoh, Keisuke

2013-04-01

As increasing evidence suggest that α(1)-blockers prevent benign prostatic hyperplasia related overactive bladder and nocturia in the human, we investigated the effects of silodosin and naftopidil on hypertension-related bladder dysfunction in the spontaneously hypertensive rat (SHR) model. Twelve-week-old male SHRs received no treatment or treatment with silodosin (100 µg/kg, p.o.) or naftopidil (10 or 30 mg/kg, p.o.) once daily for 6 weeks. Wistar rats were used as normotensive controls. After 6-week treatment, voiding functions were estimated by metabolic cages (dark- and light-cycle separately) and cystometric studies. Furthermore, the bladder blood flow (BBF) was measured employing the hydrogen clearance method. SHRs showed significant increases in micturition frequency, and decreases in BBF and single voided volume in both metabolic cages and cystometrograms compared to the Wistar group. Treatment with silodosin normalized the decreased BBF, and treatment with naftopidil increased the BBF in a dose-dependent manner in the SHR group. Although treatment with silodosin and the high dose of naftopidil significantly inhibited micturition frequency in one day, only treatment with the high dose of naftopidil significantly inhibited micturition frequency and urine production in the light-cycle compared to the non-treated SHRs. Although treatment with silodosin and the high dose of naftopidil significantly increased single voided volume, only treatment with silodosin significantly inhibited non-voiding contractions in the cystometrgrams. Our data suggest that both silodosin and naftopidil improve hypertension-related bladder dysfunction in the SHR, and naftopidil but not silodosin improves urinary frequency in the light-cycle due to inhibition of urine production. Copyright © 2012 Wiley Periodicals, Inc.

Analysis of endoscopic third ventriculostomy patency by MRI: value of different pulse sequences, the sequence parameters, and the imaging planes for investigation of flow void.

PubMed

Dinçer, Alp; Yildiz, Erdem; Kohan, Saeed; Memet Özek, M

2011-01-01

The aim of the study is to evaluate the efficiency of turbo spin-echo (TSE), three-dimensional constructive interference in the steady state (3D CISS) and cine phase contrast (Cine PC) sequences in determining flow through the endoscopic third ventriculostomy (ETV) fenestration, and to determine the effect of various TSE sequence parameters. The study was approved by our institutional review board and informed consent from all patients was obtained. Two groups of patients were included: group I (24 patients with good clinical outcome after ETV) and group II (22 patients with hydrocephalus evaluated preoperatively). The imaging protocol for both groups was identical. TSE T2 with various sequence parameters and imaging planes, and 3D CISS, followed by cine PC were obtained. Flow void was graded as four-point scales. The sensitivity, specificity, accuracy, positive and negative predictive values of sequences were calculated. Bidirectional flow through the fenestration was detected in all group I patients by cine PC. Stroke volumes through the fenestration in group I ranged 10-160.8 ml/min. There was no correlation between the presence of reversed flow and flow void grading. Also, there was no correlation between the stroke volumes and flow void grading. The sensitivity of 3D CISS was low, and 2 mm sagittal TSE T2, nearly equal to cine PC, provided best result. Cine PC and TSE T2 both have high confidence in the assessment of the flow through the fenestration. But, sequence parameters significantly affect the efficiency of TSE T2.

Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. I. Polydisperse spheres.

PubMed

Zachary, Chase E; Jiao, Yang; Torquato, Salvatore

2011-05-01

Hyperuniform many-particle distributions possess a local number variance that grows more slowly than the volume of an observation window, implying that the local density is effectively homogeneous beyond a few characteristic length scales. Previous work on maximally random strictly jammed sphere packings in three dimensions has shown that these systems are hyperuniform and possess unusual quasi-long-range pair correlations decaying as r(-4), resulting in anomalous logarithmic growth in the number variance. However, recent work on maximally random jammed sphere packings with a size distribution has suggested that such quasi-long-range correlations and hyperuniformity are not universal among jammed hard-particle systems. In this paper, we show that such systems are indeed hyperuniform with signature quasi-long-range correlations by characterizing the more general local-volume-fraction fluctuations. We argue that the regularity of the void space induced by the constraints of saturation and strict jamming overcomes the local inhomogeneity of the disk centers to induce hyperuniformity in the medium with a linear small-wave-number nonanalytic behavior in the spectral density, resulting in quasi-long-range spatial correlations scaling with r(-(d+1)) in d Euclidean space dimensions. A numerical and analytical analysis of the pore-size distribution for a binary maximally random jammed system in addition to a local characterization of the n-particle loops governing the void space surrounding the inclusions is presented in support of our argument. This paper is the first part of a series of two papers considering the relationships among hyperuniformity, jamming, and regularity of the void space in hard-particle packings.

Asymmetric bubble collapse

NASA Astrophysics Data System (ADS)

Lai, Lipeng; Turitsyn, Konstantin S.; Zhang, Wendy W.

2008-11-01

Recent studies reveal that an inertial implosion, analogous to the collapse of a large cavity in water, governs how a submerged air bubble disconnects from a nozzle. For the bubble, slight asymmetries in the initial neck shape give rise to vibrations that grow pronounced over time. These results motivate our study of the final stage of asymmetric cavity collapse. We are particularly interested in the generic situation where the initial condition is sufficiently well-focused that a cavity can implode inwards energetically. Yet, because the initial condition is not perfectly symmetric, the implosion fails to condense all the energy. We consider cavity shapes in the slender-body limit, for which the collapse dynamics is quasi two-dimensional. In this limit, each cross-section of the cavity evolves as if it were a distorted void immersed in an inviscid and irrotational fluid. Simulations of a circular void distorted by an elongation-compression vibrational mode reveal that a variety of outcomes are possible in the 2D problem. Opposing sides of the void surface can curve inwards and contact smoothly in a finite amount of time. Depending on the phase of the vibration excited, the contact can be either north-south or east-west. Phase values that lie in the transition zone from one orientation to the other give rise to final shapes with large lengthscale separation. We show also that the final outcome varies non-monotonically with the initial amplitude of the vibrational mode.

Expression of brain derived-neurotrophic factor and granulocyte-colony stimulating factor in the urothelium: relation with voiding function.

PubMed

Yuk, Seung Mo; Shin, Ju Hyun; Song, Ki Hak; Na, Yong Gil; Lim, Jae Sung; Sul, Chong Koo

2015-05-08

We designed this experiment to elucidate the relationship between the expression of brain derived-neurotrophic factor (BDNF), the expression of granulocyte-colony stimulating factor (G-CSF), and the development of overactive bladder (OAB). In our previous study, the urothelium was observed to be more than a simple mechanosensory receptor and was found to be a potential therapeutic target for OAB. Moreover, neuregulin-1 and BDNF were found to be potential new biomarkers of OAB. Here, we investigated the relationship between changes in the voiding pattern and the expression of BDNF and G-CSF in the urothelium and evaluated the effects of 5-hydroxymethyl tolterodine (5-HMT) on rats with bladder outlet obstruction (BOO). A total of 100 Sprague-Dawley rats were divided into the following groups: 20 control rats; 40 BOO rats; and 40 BOO rats administered 5-HMT (0.1 mg/kg). After BOO was induced for 4 weeks, the rats were assessed by cystometrography. The changes in BDNF and G-CSF expression were examined in both separated urothelial tissues and in cultured urothelial cells by reverse transcription polymerase chain reaction (RT-PCR). BOO rats showed increased non-voiding activity [NVA; (number/10 voidings)] and bladder weight and decreased micturition volume (MV), micturition interval (MI), and micturition time (MT) relative to the controls. Moreover, the 5-HMT administration rats showed decreased NVA and bladder weight and increased MV and MI in comparison to the BOO rats. BDNF and G-CSF expression was increased in BOO rats and decreased following 5-HMT administration. In this model, voiding dysfunction developed as a result of BOO. As a therapeutic agent for OAB, the administration of 5-HMT improved the voiding dysfunction. BDNF and G-CSF might modulate voiding patterns through micturition pathways and might be involved only in the urothelium. Moreover, the expression of both genes in the urothelium might be related to voiding dysfunction in OAB patients. Thus, the urothelium has an important role in the manifestation of voiding symptoms.

Average luminosity distance in inhomogeneous universes

NASA Astrophysics Data System (ADS)

Kostov, Valentin Angelov

Using numerical ray tracing, the paper studies how the average distance modulus in an inhomogeneous universe differs from its homogeneous counterpart. The averaging is over all directions from a fixed observer not over all possible observers (cosmic), thus it is more directly applicable to our observations. Unlike previous studies, the averaging is exact, non-perturbative, an includes all possible non-linear effects. The inhomogeneous universes are represented by Sweese-cheese models containing random and simple cubic lattices of mass- compensated voids. The Earth observer is in the homogeneous cheese which has an Einstein - de Sitter metric. For the first time, the averaging is widened to include the supernovas inside the voids by assuming the probability for supernova emission from any comoving volume is proportional to the rest mass in it. For voids aligned in a certain direction, there is a cumulative gravitational lensing correction to the distance modulus that increases with redshift. That correction is present even for small voids and depends on the density contrast of the voids, not on their radius. Averaging over all directions destroys the cumulative correction even in a non-randomized simple cubic lattice of voids. Despite the well known argument for photon flux conservation, the average distance modulus correction at low redshifts is not zero due to the peculiar velocities. A formula for the maximum possible average correction as a function of redshift is derived and shown to be in excellent agreement with the numerical results. The formula applies to voids of any size that: (1) have approximately constant densities in their interior and walls, (2) are not in a deep nonlinear regime. The actual average correction calculated in random and simple cubic void lattices is severely damped below the predicted maximum. That is traced to cancelations between the corrections coming from the fronts and backs of different voids at the same redshift from the observer. The calculated correction at low redshifts allows one to readily predict the redshift at which the averaged fluctuation in the Hubble diagram is below a required precision and suggests a method to extract the background Hubble constant from low redshift data without the need to correct for peculiar velocities.

Enhanced phonon scattering by nanovoids in high thermoelectric power factor polysilicon thin films

NASA Astrophysics Data System (ADS)

Dunham, Marc T.; Lorenzi, Bruno; Andrews, Sean C.; Sood, Aditya; Asheghi, Mehdi; Narducci, Dario; Goodson, Kenneth E.

2016-12-01

The ability to tune the thermal conductivity of semiconductor materials is of interest for thermoelectric applications, in particular, for doped silicon, which can be readily integrated in electronic microstructures and have a high thermoelectric power factor. Here, we examine the impact of nanovoids on the thermal conductivity of highly doped, high-power factor polysilicon thin films using time-domain thermoreflectance. Voids are formed through ion implantation and annealing, evolving from many small (˜4 nm mean diameter) voids after 500 °C anneal to fewer, larger (˜29 nm mean diameter) voids with a constant total volume fraction after staged thermal annealing to 1000 °C. The thermal conductivity is reduced to 65% of the non-implanted reference film conductivity after implantation and 500 °C anneal, increasing with anneal temperature until fully restored after 800 °C anneal. The void size distributions are determined experimentally using small-angle and wide-angle X-ray scattering. While we believe multiple physical mechanisms are at play, we are able to corroborate the positive correlation between measurements of thermal conductivity and void size with Monte Carlo calculations and a scattering probability based on Matthiessen's rule. The data suggest an opportunity for thermal conductivity suppression combined with the high power factor for increased material zT and efficiency of nanostructured polysilicon as a thermoelectric material.

Uroflowmetry nomograms for healthy children 5 to 15 years old.

PubMed

Gupta, Dheeraj Kumar; Sankhwar, Satya Narayan; Goel, Apul

2013-09-01

We determined flow rates and generated flow rate-voided volume nomograms based on healthy children 5 to 15 years old voiding spontaneously in their natural environment. A total of 824 healthy school children of both genders were enrolled. A single uroflow record from each child was evaluated. A total of 103 children with a voided volume of less than 50 ml and/or a staccato/interrupted uroflow pattern were excluded, and 721 records were analyzed. Data were evaluated using several mathematical formulas and goodness of fit was determined. Linear regression analysis was used to generate nomograms. Flow rates and voided volumes increased with increasing age, with the effect being more pronounced in girls. No significant difference was noted in uroflow rates from 5 to 10 years, but significant differences (p <0.001) started appearing at 11 to 15 years. Also no significant difference was noted in uroflow rates among children 11 to 15 years. Therefore, 2 age groups were designated, with group 1 consisting of patients 5 to 10 years old and group 2 consisting of patients 11 to 15 years old. There were 222 boys and 122 girls in group 1 and 240 boys and 137 girls in group 2. In group 1 the maximum and average ± SD flow rates were 15.26 ± 4.54 ml per second and 7.68 ± 3.26 ml per second, respectively, for boys and 17.98 ± 6.06 ml per second and 9.19 ± 4.23 ml per second, respectively, for girls. In group 2 these rates were 22.50 ± 7.24 ml per second and 10.78 ± 4.03 ml per second, respectively, for boys and 27.16 ± 9.37 ml per second and 13.48 ± 5.21 ml per second, respectively, for girls. This large study, which expands the scant existing literature on uroflow parameters in healthy children, will hopefully promote wider application of uroflowmetry testing in the pediatric population. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Prevalence, incidence, and resolution of nocturnal polyuria in a longitudinal community-based study in older men: the Krimpen study.

PubMed

van Doorn, Boris; Blanker, Marco H; Kok, Esther T; Westers, Paul; Bosch, J L H Ruud

2013-03-01

Nocturnal polyuria (NP) is common in older men and can lead to nocturia. However, no longitudinal data are available on the natural history of NP. To determine prevalence, incidence, and resolution rates of NP. A longitudinal, community-based study was conducted among 1688 men aged 50-78 yr in Krimpen aan den IJssel, The Netherlands (reference date: 1995), with planned follow-up rounds at 2, 4, and 6 yr. NP was determined with frequency-volume charts. Two definitions of NP were used: (1) a nocturnal urine production (NUP) of >90 ml/h (NUP90) and (2) the nocturnal voided volume plus first morning void being >33% of the 24-h voided volume (NUV33). Nocturia was defined as two or more voids per night. We determined the prevalence of NP at each study round. At first follow-up, we determined the incidence in men without baseline NP and the resolution in men with baseline NP. Prevalence of NP in men with or without nocturia was also determined. At baseline, the prevalence of NUP90 was 15.0% and increased to 21.7% after 6.5 yr, whereas the prevalence of NUV33 was 77.8% at baseline and 80.5% after 6.5 yr. At 2.1 yr of follow-up, the incidences of NUP90 and NUV33 were 13.6% and 60.3%, respectively, and the resolution rates were 57.0% and 17.8%, respectively. Because of this fluctuation in NP, no reliable long-term incidences could be calculated. At baseline, NUP90 was prevalent in 27.7% of men with nocturia and in 8.0% of those without nocturia. At baseline, NUV33 was prevalent in 91.9% of men with nocturia and in 70.1% of men without nocturia. Due to the fluctuation of NP, it is advisable to first determine its chronicity and cause before starting treatment. Because of the high prevalence of NP in men without nocturia, NUV33 should be reconsidered as a discriminative definition of NP. Copyright © 2012. Published by Elsevier B.V.

Management of non-neuropathic underactive bladder in children with voiding dysfunction by animated biofeedback: a randomized clinical trial.

PubMed

Ladi-Seyedian, Sanam; Kajbafzadeh, Abdol-Mohammad; Sharifi-Rad, Lida; Shadgan, Babak; Fan, Eileen

2015-01-01

To assess the efficacy of animated biofeedback and pelvic floor muscle (PFM) exercise in managing children with non-neuropathic underactive bladder (UB). A total of 50 children with UB without underlying neuropathic disease, aged 5-16 years, were included in this study. They were randomly divided into 2 equal treatment groups comprising standard urotherapy (hydration, scheduled voiding, toilet training, and diet) with (group A) or without (group B) animated biofeedback and PFM exercise. The follow-up period for each participant was 1 year. A complete voiding and bowel habit diary was recorded by participants' parents before and after 2 evaluations. In addition, uroflowmetry with electromyography and bladder ultrasound were performed before, 6 months, and 1 year after treatment. Results were compared between the 2 cohorts. Mean number of voiding episodes was significantly increased in group A after biofeedback therapy compared with group B with only standard urotherapy (6.6 ± 1.6 vs 4.5 ± 1 times a day; P <.000). Urinary tract infection did not relapse in 9 of 11 (81%) and 8 of 15 (38%) patients in groups A and B, respectively (P <.02). Postvoid residual volume and voiding time decreased considerably, whereas maximum urine flow increased significantly in group A compared with group B (17.2 ± 4.7 vs 12.9 ± 4.6 mL/s; P <.01). Combination of animated biofeedback and PFM exercise effectively improves sensation of bladder fullness and contractility in children with UB due to voiding dysfunction. Copyright © 2015 Elsevier Inc. All rights reserved.

Cluster analysis identifies three urodynamic patterns in patients with orthotopic neobladder reconstruction.

PubMed

Kim, Kwang Hyun; Yoon, Hyun Suk; Song, Wan; Choo, Hee Jung; Yoon, Hana; Chung, Woo Sik; Sim, Bong Suk; Lee, Dong Hyeon

2017-01-01

To classify patients with orthotopic neobladder based on urodynamic parameters using cluster analysis and to characterize the voiding function of each group. From January 2012 to November 2015, 142 patients with bladder cancer underwent radical cystectomy and Studer neobladder reconstruction at our institute. Of the 142 patients, 103 with complete urodynamic data and information on urinary functional outcomes were included in this study. K-means clustering was performed with urodynamic parameters which included maximal cystometric capacity, residual volume, maximal flow rate, compliance, and detrusor pressure at maximum flow rate. Three groups emerged by cluster analysis. Urodynamic parameters and urinary function outcomes were compared between three groups. Group 1 (n = 44) had ideal urodynamic parameters with a mean maximal bladder capacity of 513.3 ml and mean residual urine volume of 33.1 ml. Group 2 (n = 42) was characterized by small bladder capacity with low compliance. Patients in group 2 had higher rates of daytime incontinence and nighttime incontinence than patients in group 1. Group 3 (n = 17) was characterized by large residual urine volume with high compliance. When we examined gender differences in urodynamics and functional outcomes, residual urine volume and the rate of daytime incontinence were only marginally significant. However, females were significantly more likely to belong to group 2 or 3 (P = 0.003). In multivariate analysis to identify factors associated with group 1 which has the most ideal urodynamic pattern, age (OR 0.95, P = 0.017) and male gender (OR 7.57, P = 0.003) were identified as significant factors. While patients with ileal neobladder present with various voiding symptoms, three urodynamic patterns were identified by cluster analysis. Approximately half of patients had ideal urodynamic parameters. The other two groups were characterized by large residual urine and small capacity bladder with low compliance. Young age and male gender appear to have a favorable impact on urodynamic and voiding outcomes in patients undergoing orthotopic neobladder reconstruction.

Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage

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

Pfeifer, Peter; Gillespie, Andrew; Stalla, David

The purpose of the project “Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage” is the development of materials that store hydrogen (H 2) by adsorption in quantities and at conditions that outperform current compressed-gas H 2 storage systems for electric power generation from hydrogen fuel cells (HFCs). Prominent areas of interest for HFCs are light-duty vehicles (“hydrogen cars”) and replacement of batteries with HFC systems in a wide spectrum of applications, ranging from forklifts to unmanned areal vehicles to portable power sources. State-of-the-art compressed H 2 tanks operate at pressures between 350 and 700 bar at ambient temperature and storemore » 3-4 percent of H 2 by weight (wt%) and less than 25 grams of H 2 per liter (g/L) of tank volume. Thus, the purpose of the project is to engineer adsorbents that achieve storage capacities better than compressed H 2 at pressures less than 350 bar. Adsorption holds H 2 molecules as a high-density film on the surface of a solid at low pressure, by virtue of attractive surface-gas interactions. At a given pressure, the density of the adsorbed film is the higher the stronger the binding of the molecules to the surface is (high binding energies). Thus, critical for high storage capacities are high surface areas, high binding energies, and low void fractions (high void fractions, such as in interstitial space between adsorbent particles, “waste” storage volume by holding hydrogen as non-adsorbed gas). Coexistence of high surface area and low void fraction makes the ideal adsorbent a nanoporous monolith, with pores wide enough to hold high-density hydrogen films, narrow enough to minimize storage as non-adsorbed gas, and thin walls between pores to minimize the volume occupied by solid instead of hydrogen. A monolith can be machined to fit into a rectangular tank (low pressure, conformable tank), cylindrical tank (high pressure), or other tank shape without any waste of volume.« less

The coupled effect of fiber volume fraction and void fraction on hydraulic fluid absorption of quartz/BMI laminates

NASA Astrophysics Data System (ADS)

Hurdelbrink, Keith R.; Anderson, Jacob P.; Siddique, Zahed; Altan, M. Cengiz

2016-03-01

Bismaleimide (BMI) resin with quartz (AQ581) fiber reinforcement is a composite material frequently used in aerospace applications, such as engine cowlings and radomes. Various composite components used in aircrafts are exposed to different types of hydraulic fluids, which may lead to anomalous absorption behavior over the service life of the composite. Accurate predictive models for absorption of liquid penetrants are particularly important as the composite components are often exposed to long-term degradation due to absorbed moisture, hydraulic fluids, or similar liquid penetrants. Microstructural features such as fiber volume fraction and void fraction can have a significant effect on the absorption behavior of fiber-reinforced composites. In this paper, hydraulic fluid absorption characteristics of quartz/BMI laminates fabricated from prepregs preconditioned at different relative humidity and subsequently cured at different pressures are presented. The composite samples are immersed into hydraulic fluid at room temperature, and were not subjected to any prior degradation. To generate process-induced microvoids, prepregs were conditioned in an environmental chamber at 2% or 99% relative humidity at room temperature for a period of 24 hours prior to laminate fabrication. To alter the fiber volume fraction, the laminates were fabricated at cure pressures of 68.9 kPa (10 psi) or 482.6 kPa (70 psi) via a hot-press. The laminates are shown to have different levels of microvoids and fiber volume fractions, which were observed to affect the absorption dynamics considerably and exhibited clear non-Fickian behavior. A one-dimensional hindered diffusion model (HDM) was shown to be successful in predicting the hydraulic fluid absorption. Model prediction indicates that as the fabrication pressure increased from 68.9 kPa to 482.6 kPa, the maximum fluid content (M∞) decreased from 8.0% wt. to 1.0% wt. The degree of non-Fickian behavior, measured by hindrance coefficient (μ), was shown to increase with the increased void fraction.

Ductile failure initiation and evolution in porous polycrystalline aggregates due to interfacial effects

NASA Astrophysics Data System (ADS)

Ashmawi, Waeil Muhammad Al-Anwar

New analytical and computational formulations have been developed for the investigation of micro structurally induced ductile failure mechanisms in porous polycrystalline aggregates with low and high (CSL) angle grain-boundaries (GBs). A multiple-slip rate-dependent crystalline constitutive formulation that is coupled to the evolution of mobile and immobile dislocation densities, a new internal porosity formulation for void nucleation and growth, and specialized computational schemes have been developed to obtain a detailed understanding of the multi-scale interrelated physical mechanisms that result in ductile failure in polycrystalline materials. Comprehensive transmission and pile-up mechanisms have also been introduced to investigate dislocation-density impedance and slip-rate incompatibility at the GBs. The interrelated effects of GB orientation, mobile and immobile dislocation densities, strain hardening, geometrical softening, localized plastic strains, and dislocation-density transmission and blockage on void growth, interaction, and coalescence have been studied. Criteria have been developed to identify and monitor the initiation and development of potential dislocation-density activity sites adjacent to GB regions. These interactions play an important role in the formation of GB pile-up and transmission regions. The effects of GB structure and orientation on ductile failure have been accounted for by the development of GB interfacial kinematic conditions that account for a multitude of dislocation-density interactions with GBs, such as full and partial transmission, impedance, blockage, and absorption. Pile-ups and transmission regions are identified and monitored as the deformation and failure evolve. These kinematic conditions are linked to the initiation and evolution of failure modes by the development of a new internal porosity evolution formulation that accounts for void nucleation and growth. The internal porosity relation is coupled with the proposed dislocation-density based crystalline constitutive formulation, the interfacial GB dislocation-density interaction models, and the specialized computational schemes to obtain detailed predictions of the behavior of aggregates with explicit voids that have different orientations and combinations of sizes, shapes, and spacings. Results from the present study indicate that material failure is a competition between different interrelated effects, such as stress triaxiality, accumulated plastic shear strain, temperature, dislocation density concentration, and grain and GB crystallographic orientations. For all void arrangements, as the void size is increased, specimen necking is diffuse and failure is concentrated in the ligament regions. Furthermore, there are more dislocation-density activity sites for potential transmission and pile-ups at the GBs. Failure is concentrated along the void peripheries and within intervoid ligaments. It has been shown that the evolution of the mobile dislocation density saturation curves, and their saturation rate are directly related to the aggregate response. Nucleation and growth for all void distributions have occurred in regions of maximum dislocation density and along preferred crystallographic orientations. Spatial distributions of porosity, accumulated plastic strains, and pressure have been obtained to further elucidate how these parameters evolve and affect void to void interaction in critical ligament and localized regions as a function of intervoid spacing and nominal strains. These failure predictions can be also used to identify intergranular and transgranular failure propagation. The present study underscores the importance of using dislocation-density based multiple-slip crystalline constitutive formulations and GB interfacial mechanisms that are consistent with experimental observations and results to accurately characterize the microstructural evolution of deformation and failure modes on a length scale that is commensurate with the material competition between the inherent strengthening and softening mechanisms of crystalline systems.

Is sensory urgency part of the same spectrum of bladder dysfunction as detrusor overactivity?

PubMed

Haylen, Bernard T; Chetty, Naven; Logan, Vanessa; Schulz, Serena; Verity, Louise; Law, Matthew; Zhou, Jialun

2007-02-01

It has been suggested that the urogynecological diagnosis of sensory urgency is an early form of detrusor overactivity and may be just earlier in the spectrum of disease. The former term is generally defined as increased perceived bladder sensation during filling, a low first desire to void and low bladder capacity in the absence of recorded urinary tract infection (UTI) or detrusor overactivity. The aims of this study are to determine the prevalence and associations of sensory urgency in comparison with detrusor overactivity, and whether sensory urgency is shown to be in the same spectrum of bladder dysfunction as detrusor overactivity. Five hundred and ninety-two women attending for an initial urogynecological/urodynamic assessment took part in this prospective study. In addition to a full clinical assessment, all women underwent free uroflowmetry, residual urine volume measurement (by vaginal ultrasound) and multichannel filling and voiding cystometry. Data were separated into those having (1) sensory urgency or (2) detrusor overactivity. Apart from prevalence figures, comparative associations were sought for (3) age; (4) parity; (5) presenting symptoms; (6) presence of at least one (medically) documented UTI in the previous 12 months; (7) two or more (recurrent) documented UTIs in the previous 12 months; (8) prior hysterectomy; (9) prior continence surgery; (10) menopause; (11) menopause and HRT use; (12) sign of clinical stress leakage; (13) retroverted uterus; (14) anterior vaginal wall prolapse; (15) uterine prolapse; (16) posterior vaginal wall prolapse; (17) apical vaginal prolapse; (18, 19) maximum, average urine flow rate (MUFR, AUFR) centiles, Liverpool Nomograms; (20) median residual urine volume (RUV) in milliliters; (21, 22) voiding difficulty: VD1,VD2 (MUFR, AUFR under 10th centile Liverpool Nomogram and/or RUV >30 ml); (23) diagnosis of urodynamic stress incontinence and (24) diagnosis of uterine and/or vaginal prolapse (grade >0). The prevalence of sensory urgency was 13%. The only differences in the clinical and urodynamic profiles of it and detrusor overactivity were (1) significantly increased prevalence of the symptom of urge incontinence and (2) (by definition) abnormal detrusor contractions during filling cystometry in women with detrusor overactivity. Overall, sensory urgency and detrusor overactivity appear to be part of the same spectrum of bladder dysfunction.

Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel

PubMed Central

Park, Jaeyeong; Kim, Jung-Su; Kang, Minju; Sohn, Seok Su; Cho, Won Tae; Kim, Hyoung Seop; Lee, Sunghak

2017-01-01

TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties. PMID:28067318

Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel

NASA Astrophysics Data System (ADS)

Park, Jaeyeong; Kim, Jung-Su; Kang, Minju; Sohn, Seok Su; Cho, Won Tae; Kim, Hyoung Seop; Lee, Sunghak

2017-01-01

TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.

Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel.

PubMed

Park, Jaeyeong; Kim, Jung-Su; Kang, Minju; Sohn, Seok Su; Cho, Won Tae; Kim, Hyoung Seop; Lee, Sunghak

2017-01-09

TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.

Fabrication of CNT@void@SnO2@C with tube-in-tube nanostructure as high-performance anode for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Tian, Qinghua; Tian, Yang; Zhang, Zhengxi; Yang, Li; Hirano, Shin-ichi

2015-09-01

Tin dioxide/carbon composites is an important class of promising candidates for anode materials with superior electrochemical performance and thus have attracted extensive attention. Herein, a tube-in-tube nanostructure, denoted as CNT@void@SnO2@C, has been fabricated by a facile and novel strategy. The possible formation mechanism is also discussed and determined by TEM, XRD and XPS characterizations. As a promising anode material for lithium-ion batteries, the CNT@void@SnO2@C exhibits superior lithium storage properties, delivering a reversible capacity of 702.5 mAh g-1 at 200 mA g-1 even after 350 cycles. The excellent performances should be benefited from the peculiar tube-in-tube nanostructure, in which SnO2 located between CNT and outermost carbon coating layers can sure the structural integrity and high conductivity during long-term cycling, and one-dimensional void space formed between the inner CNT and outer SnO2@C nanotubes, in particular, can provide larger free space for alleviating the huge volume variation of SnO2 and accommodating the stress formed during repeated discharge/charge process.

Effect of void shape in Czochralski-Si wafers on the intensity of laser-scattering

NASA Astrophysics Data System (ADS)

Takahashi, J.; Kawakami, K.; Nakai, K.

2001-06-01

The shape effect of anisotropic-shaped microvoid defects in Czochralski-grown silicon wafers on the intensity of laser scattering has been investigated. The size and shape of the defects were examined by means of transmission electron microscopy. Octahedral voids in conventional (nitrogen-undoped) wafers showed an almost isotropic scattering property under the incident condition of a p-polarization beam. On the other hand, parallelepiped-plate-shaped voids in nitrogen-doped wafers showed an anisotropic scattering property on both p- and s-polarized components of scattered light, depending strongly on the incident laser direction. The measured results were explained not by scattering calculation using Born approximation but by calculation based on Rayleigh scattering. It was found that the s component is explained by an inclination of a dipole moment induced on a defect from the scattering plane. Furthermore, using numerical electromagnetic analysis it was shown that the asymmetric behavior of the s component on the parallelepiped-plate voids is ascribed to the parallelepiped shape effect. These results suggest that correction of the scattering intensity is necessary to evaluate the size and volume of anisotropic-shaped defects from the scattered intensity.

Gas-liquid Phase Distribution and Void Fraction Measurements Using the MRI

NASA Technical Reports Server (NTRS)

Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.

2004-01-01

We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction distributions and flow patterns in gas-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.

Increased Urinary Adenosine Triphosphate in Patients With Bladder Outlet Obstruction Due to Benign Prostate Hyperplasia.

PubMed

Silva-Ramos, Miguel; Silva, Isabel; Oliveira, José Carlos; Correia-de-Sá, Paulo

2016-11-01

Diagnosis of bladder outflow obstruction (BOO) in patients with lower urinary tract (LUT) symptoms is challenging without using invasive urodynamic tests. Recently, we showed in vitro that urothelial strips from patients with benign prostatic hyperplasia (BPH) release more ATP than controls. Here, we tested whether urinary ATP can be used as a wall tension transducer non-invasive biomarker to detect BOO in patients with BPH. 79 male patients with BOO and 22 asymptomatic controls were recruited prospectively. Patients were asked to complete the International Prostate Symptom Score (IPSS) questionnaire and to void at normal desire into a urinary flowmeter; the postvoid residual volume was determined by suprapubic ultrasonography. Urine samples from all individuals were examined for ATP, creatinine, and lactate dehydrogenase. BOO patients had significantly higher (P < 0.001) urinary ATP normalized by the voided volume (456 ± 36 nmol) than age-matched controls (209 ± 35 nmol). Urinary ATP amounts increased with the voided volume, but the slope of this rise was higher in BOO patients than in controls. A negative correlation was detected between urinary ATP and flow rate parameters, namely maximal flow rate (r = -0.310, P = 0.005), Siroky flow-volume normalization (r = -0.324, P = 0.004), and volume-normalized flow rate index (r = -0.320, P = 0.012). We found no correlation with LUT symptoms IPSS score. Areas under the receiver operator characteristics (ROC) curves were 0.91 (95%CI 0.86-0.96, P < 0.001) for ATP alone and 0.88 (95%CI 0.81-0.94, P < 0,001) when adjusted to urinary creatinine. Patients with BOO release higher amounts of ATP into the urine than the control group. The high area under the ROC curve suggests that urinary ATP can be a high-sensitive non-invasive biomarker of BOO, which may have a discriminative value of detrusor competence when comparing BPH patients with low urinary flow rates. Prostate 76:1353-1363, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Comparisons of urodynamic findings and voiding habits in patients with concomitant benign prostatic hyperplasia and detrusor overactivity presenting with or without the symptom of urgency.

PubMed

Tong, Yat-Ching

2007-01-01

The urodynamic findings and voiding habits in patients with concomitant clinical benign prostatic hyperplasia (BPH) and detrusor overactivity (DO) presenting with or without the symptom of urgency were compared. 84 BPH patients with an urodynamic diagnosis of DO by conventional cystometry were included in the study. The patients were grouped according to the presence or absence of the symptom of urgency. The urodynamic findings, urinary diary and clinical information were analyzed. Among the 84 BPH-DO patients, 52 reported the symptom of urgency while 32 did not. There were no significant differences in mean age, International Prostate Symptom Score and flow rate between the two groups. Patients without urgency had a higher incidence of terminal DO and abnormal bladder sensation. The occurrence of unfelt phasic DO was also significantly higher in this group. Sphincter electromyography showed conscious and subconscious sphincter contractions associated with DO. The urinary diary showed lower 24-hour urinary output, smaller bladder functional capacity and average voided volume in the BPH-DO patients without urgency. BPH patients with DO may neglect the symptom of urgency due to abnormal bladder sensation, or negate the symptom by subconscious sphincter contraction to abort the overactivity. Some may avoid the symptom by drinking less fluid and emptying the bladder at a smaller volume. Copyright 2007 S. Karger AG, Basel.

Comparison of flowrates and voided volumes during non-instrumented uroflowmetry and pressure-flow studies in women with stress incontinence.

PubMed

Mueller, Elizabeth R; Litman, Heather; Rickey, Leslie R; Sirls, Larry; Norton, Peggy; Wilson, Tracey; Moalli, Pamela; Albo, Michael; Zimmern, Philippe

2015-08-01

The Blaivas-Groutz nomogram defines voiding obstruction in women using Qmax from the NIF and the maximum detrusor pressure (Pdetmax ) from the PFS. The aim of this study was to understand the relationship between NIF and PFS maximum flow rates in women with stress incontinence. We analyzed the UDS of 597 women with stress-dominant urinary incontinence. Each subject underwent a NIF and then a PFS. Mixed model was used to test the hypothesis that the relationship between flow rates and voided volume (VV) were similar for NIF and PFS. There were 452 subjects with both NIF and PFS studies that met the inclusion criteria and had max flow rate (Qmax ) for both NIF and PFS. The mean age was 53. Overall, higher VV were observed during PFS compared to NIF and subjects had higher Qmax with NIF compared to PFS. The relationship between Qmax and VV was significantly different between NIF and PFS (P < 0.004). At 200 ml, NIF Qmax was 14% higher than PFS Qmax and this difference increased to 30% at 700 ml. The difference between PFS Qmax and NIF Qmax increases as VV increase. As a result, values from PFS and NIF cannot be used interchangeably as has been suggested in the Blaivas-Groutz nomogram for obstruction in women. © 2014 Wiley Periodicals, Inc.

A practical method for estimating maximum shear modulus of cemented sands using unconfined compressive strength

NASA Astrophysics Data System (ADS)

Choo, Hyunwook; Nam, Hongyeop; Lee, Woojin

2017-12-01

The composition of naturally cemented deposits is very complicated; thus, estimating the maximum shear modulus (Gmax, or shear modulus at very small strains) of cemented sands using the previous empirical formulas is very difficult. The purpose of this experimental investigation is to evaluate the effects of particle size and cement type on the Gmax and unconfined compressive strength (qucs) of cemented sands, with the ultimate goal of estimating Gmax of cemented sands using qucs. Two sands were artificially cemented using Portland cement or gypsum under varying cement contents (2%-9%) and relative densities (30%-80%). Unconfined compression tests and bender element tests were performed, and the results from previous studies of two cemented sands were incorporated in this study. The results of this study demonstrate that the effect of particle size on the qucs and Gmax of four cemented sands is insignificant, and the variation of qucs and Gmax can be captured by the ratio between volume of void and volume of cement. qucs and Gmax of sand cemented with Portland cement are greater than those of sand cemented with gypsum. However, the relationship between qucs and Gmax of the cemented sand is not affected by the void ratio, cement type and cement content, revealing that Gmax of the complex naturally cemented soils with unknown in-situ void ratio, cement type and cement content can be estimated using qucs.

Testosterone-induced benign prostatic hyperplasia rat and dog as facile models to assess drugs targeting lower urinary tract symptoms

PubMed Central

Li, Jing; Tian, Yanxin; Guo, Shimeng; Gu, Haifeng; Yuan, Qianting; Xie, Xin

2018-01-01

Benign prostatic hyperplasia (BPH) is an age-related disease, affecting a majority of elderly men worldwide. Medical management of BPH is an alternative to surgical treatment of this disease. Currently, α1-adrenergic receptor (α1-AR) antagonists are among the first line drugs to treat BPH by reducing the tension of urinary track and thus the obstructive symptoms in voiding. In drug development, old male dogs with spontaneous BPH are considered the golden standard of the animal models. However, old dogs (>6 years) are expensive and not all old dogs develop BPH. So it is necessary to develop more accessible animal models for drug efficacy evaluation. Here we describe the development of testosterone-induced BPH models in both rats and young adult dogs and their applications in the in vivo evaluation of α1-AR antagonist. The BPH rats and dogs induced by chronic testosterone treatment have significantly increased micturition frequency and reduced mean voided volume, very similar to the clinical symptoms of BPH patients. Silodosin, an α1-AR antagonist, significantly reduces the urinary frequency and increases the voided volume in BPH model animals in a dose-dependent manner. The results demonstrate that testosterone-induced BPH rat and dog models might provide a more efficient way to evaluate micturition behavior in anti-BPH drug studies. PMID:29351556

Urodynamic findings in women with pelvic organ prolapse and obstructive voiding symptoms.

PubMed

Dain, Lena; Auslander, Ron; Rosen, Talma; Segev, Yakir; Goldschmidt, Eyal; Abramov, Yoram

2010-11-01

To determine whether obstructive voiding symptoms in women with advanced pelvic organ prolapse (POP) were associated with objective bladder outflow tract obstruction. We reviewed preoperative data from patients with advanced POP who underwent surgical correction at the Department of Obstetrics and Gynecology, Carmel Medical Center, Haifa, Israel, between December 1, 2005, and November 30, 2007. Obstructive voiding symptoms were recorded from Pelvic Floor Distress Inventory-20 questionnaires. Of the 81 women aged 44-80 years who were included in the study, 40 (49.4%) reported incomplete bladder emptying preoperatively. There was no significant difference between these women and asymptomatic women in terms of demographic and clinical parameters such as age, parity, and stage of prolapse. Furthermore, there was no significant difference with regard to postvoid residual bladder volume (52.8 ± 65.8 vs 41.6 ± 41.2 mL), maximal (23.8 ± 11 vs 21.9 ± 9.6 mL/second) and average (10.3 ± 6.2 vs 9.3 ± 4 mL/second) urinary flow velocities, prevalence of increased postvoid residual volume (10.0% vs 4.8%), or obstructive urinary flow (17.5% vs 7.3%). Almost half of all women with advanced POP experienced incomplete bladder emptying; however, this symptom did not correlate with objective urodynamic bladder outflow tract obstruction. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Local random configuration-tree theory for string repetition and facilitated dynamics of glass

NASA Astrophysics Data System (ADS)

Lam, Chi-Hang

2018-02-01

We derive a microscopic theory of glassy dynamics based on the transport of voids by micro-string motions, each of which involves particles arranged in a line hopping simultaneously displacing one another. Disorder is modeled by a random energy landscape quenched in the configuration space of distinguishable particles, but transient in the physical space as expected for glassy fluids. We study the evolution of local regions with m coupled voids. At a low temperature, energetically accessible local particle configurations can be organized into a random tree with nodes and edges denoting configurations and micro-string propagations respectively. Such trees defined in the configuration space naturally describe systems defined in two- or three-dimensional physical space. A micro-string propagation initiated by a void can facilitate similar motions by other voids via perturbing the random energy landscape, realizing path interactions between voids or equivalently string interactions. We obtain explicit expressions of the particle diffusion coefficient and a particle return probability. Under our approximation, as temperature decreases, random trees of energetically accessible configurations exhibit a sequence of percolation transitions in the configuration space, with local regions containing fewer coupled voids entering the non-percolating immobile phase first. Dynamics is dominated by coupled voids of an optimal group size, which increases as temperature decreases. Comparison with a distinguishable-particle lattice model (DPLM) of glass shows very good quantitative agreements using only two adjustable parameters related to typical energy fluctuations and the interaction range of the micro-strings.

A New Fluidized Bed Bioreactor Based on Diversion-Type Microcapsule Suspension for Bioartificial Liver Systems

PubMed Central

Li, Jianzhou; Yu, Liang; Chen, Ermei; Zhu, Danhua; Zhang, Yimin; Li, LanJuan

2016-01-01

A fluidized bed bioreactor containing encapsulated hepatocytes may be a valuable alternative to a hollow fiber bioreactor for achieving the improved mass transfer and scale-up potential necessary for clinical use. However, a conventional fluidized bed bioreactor (FBB) operating under high perfusion velocity is incapable of providing the desired performance due to the resulting damage to cell-containing microcapsules and large void volume. In this study, we developed a novel diversion-type microcapsule-suspension fluidized bed bioreactor (DMFBB). The void volume in the bioreactor and stability of alginate/chitosan microcapsules were investigated under different flow rates. Cell viability, synthesis and metabolism functions, and expression of metabolizing enzymes at transcriptional levels in an encapsulated hepatocyte line (C3A cells) were determined. The void volume was significantly less in the novel bioreactor than in the conventional FBB. In addition, the microcapsules were less damaged in the DMFBB during the fluidization process as reflected by the results for microcapsule retention rates, swelling, and breakage. Encapsulated C3A cells exhibited greater viability and CYP1A2 and CYP3A4 activity in the DMFBB than in the FBB, although the increases in albumin and urea synthesis were less prominent. The transcription levels of several CYP450-related genes and an albumin-related gene were dramatically greater in cells in the DMFBB than in those in the FBB. Taken together, our results suggest that the DMFBB is a promising alternative for the design of a bioartificial liver system based on a fluidized bed bioreactor with encapsulated hepatocytes for treating patients with acute hepatic failure or other severe liver diseases. PMID:26840840

Comparative Three‐Dimensional Morphology of Baleen: Cross‐Sectional Profiles and Volume Measurements Using CT Images

PubMed Central

Saladrigas, Amalia H.; Goldbogen, Jeremy A.

2017-01-01

ABSTRACT Baleen whales are obligate filter feeders, straining prey‐laden seawater through racks of keratinized baleen plates. Despite the importance of baleen to the ecology and natural history of these animals, relatively little work has been done on baleen morphology, particularly with regard to the three‐dimensional morphology and structure of baleen. We used computed tomography (CT) scanning to take 3D images of six baleen specimens representing five species, including three complete racks. With these images, we described the three‐dimensional shape of the baleen plates using cross‐sectional profiles from within the gum tissue to the tip of the plates. We also measured the percentage of each specimen that was composed of either keratinized plate material or was void space between baleen plates, and thus available for seawater flow. Baleen plates have a complex three‐dimensional structure with curvature that varies across the anterior‐posterior, proximal‐distal, and medial‐lateral (lingual‐labial) axes. These curvatures also vary with location along the baleen rack, and between species. Cross‐sectional profiles resemble backwards‐facing airfoils, and some specimens display S‐shaped, or reflexed, camber. Within a baleen specimen, the intra‐baleen void volume correlates with the average bristle diameter for a species, suggesting that essentially, thinner plates (with more space between them for flow) have thinner bristles. Both plate curvature and the relative proportions of plate and void volumes are likely to have implications for the mechanics of mysticete filtration, and future studies are needed to determine the particular functions of these morphological characters. Anat Rec, 300:1942–1952, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists PMID:28971628

Criticality conditions of heterogeneous energetic materials under shock loading

NASA Astrophysics Data System (ADS)

Nassar, Anas; Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

2017-06-01

Shock interaction with the microstructural heterogeneities of energetic materials can lead to the formation of locally heated regions known as hot spots. These hot spots are the potential sites where chemical reaction may be initiated. However, the ability of a hot spot to initiate chemical reaction depends on its size, shape and strength (temperature). Previous study by Tarver et al. has shown that there exists a critical size and temperature for a given shape (spherical, cylindrical, and planar) of the hot spot above which reaction initiation is imminent. Tarver et al. assumed a constant temperature variation in the hot spot. However, the meso-scale simulations show that the temperature distribution within a hot spot formed from processes such as void collapse is seldom constant. Also, the shape of a hot spot can be arbitrary. This work is an attempt towards development of a critical hot spot curve which is a function of loading strength, duration and void morphology. To achieve the aforementioned goal, mesoscale simulations are conducted on porous HMX material. The process is repeated for different loading conditions and void sizes. The hot spots formed in the process are examined for criticality depending on whether they will ignite or not. The metamodel is used to obtain criticality curves and is compared with the critical hot spot curve of Tarver et al.

Efficient Voronoi volume estimation for DEM simulations of granular materials under confined conditions

PubMed Central

Frenning, Göran

2015-01-01

When the discrete element method (DEM) is used to simulate confined compression of granular materials, the need arises to estimate the void space surrounding each particle with Voronoi polyhedra. This entails recurring Voronoi tessellation with small changes in the geometry, resulting in a considerable computational overhead. To overcome this limitation, we propose a method with the following features:•A local determination of the polyhedron volume is used, which considerably simplifies implementation of the method.•A linear approximation of the polyhedron volume is utilised, with intermittent exact volume calculations when needed.•The method allows highly accurate volume estimates to be obtained at a considerably reduced computational cost. PMID:26150975

Instabilities of Damage and Surface Degradation Mechanisms in Brittle Material Structural Systems

DTIC Science & Technology

1992-03-15

I INTRODUCTION AND SCOPE 1.1 General Brittle materials such as rock and concrete contain a multitude of defects in the form of micro-voids and/or...micro-cracks even before any external load is applied. The term "structure" is associated with such defects . During a loading- unloading process, these...voids/cracks may undergo irreversible growth and new ones may nucleate. The ultimate coalescence of such defects may result in macro- crack initiation

TMI-2 (Three Mile Island Unit 2) core region defueling

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

Rodabaugh, J.M.; Cowser, D.K.

1988-01-01

In July of 1982, a video camera was inserted into the Three Mile Island Unit 2 reactor vessel providing the first visual evidence of core damage. This inspection, and numerous subsequent data acquisition tasks, revealed a central void /approx/1.5 m (5 ft) deep. This void region was surrounded by partial length fuel assemblies and ringed on the periphery by /approx/40 full-length, but partial cross-section, fuel assemblies. All of the original 177 fuel assemblies exhibited signs of damage. The bottom of the void cavity was covered with a bed of granular rubble, fuel assembly upper end fittings, control rod spiders, fuelmore » rod fragments, and fuel pellets. It was obvious that the normal plant refueling system not suitable for removing the damaged core. A new system of defueling tools and equipment was necessary to perform this task. Design of the new system was started immediately, followed by >1 yr of fabrication. Delivery and checkout of the defueling system occurred in mid-1985. Actual defueling was initiated in late 1985 with removal of the debris bed at the bottom of the core void. Obstructions to the debris, such as end fittings and fuel rod fragments ere removed first; then /approx/23,000 kg (50,000lb) of granular debris was quickly loaded into canisters. Core region defueling was completed in late 1987, /approx/2 yr after it was initiated.« less

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

Ongari, Daniele; Boyd, Peter G.; Barthel, Senja

Pore volume is one of the main properties for the characterization of microporous crystals. It is experimentally measurable, and it can also be obtained from the refined unit cell by a number of computational techniques. In this work, we assess the accuracy and the discrepancies between the different computational methods which are commonly used for this purpose, i.e, geometric, helium, and probe center pore volumes, by studying a database of more than 5000 frameworks. We developed a new technique to fully characterize the internal void of a microporous material and to compute the probe-accessible and -occupiable pore volume. Lasty, wemore » show that, unlike the other definitions of pore volume, the occupiable pore volume can be directly related to the experimentally measured pore volumes from nitrogen isotherms.« less

Evaluation of the Superpave Gyratory Compactor for Low Volume Roads

DOT National Transportation Integrated Search

2000-06-01

There is evidence that some Kansas mixes, which have performed well in the past, will not meet the currently proposed design requirements for a Superpave level I mix. The major problem is low voids in the mineral aggregate (VMA). The major reasons fo...

Effect of heavy metals and water content on the strength of magnesium phosphate cements.

PubMed

Buj, Irene; Torras, Josep; Casellas, Daniel; Rovira, Miquel; de Pablo, Joan

2009-10-15

In this paper the mechanical properties of magnesium potassium phosphate cements used for the Stabilization/Solidification (S/S) of galvanic wastes were investigated. Surrogate wastes (metal nitrate dissolutions) were employed containing Cd, Cr(III), Cu, Ni, Pb or Zn at a concentration of 25 g dm(-3) and different water-to-solid (W/S) ratios (0.3, 0.4, 0.5 and 0.6 dm(3)kg(-1)) have been employed. Cements were prepared by mixing hard burned magnesia of about 70% purity with potassium dihydrogen phosphate. Compressive strength and tensile strength of specimens were determined. In addition the volume of permeable voids was measured. It was found that when comparing pastes that the volume of permeable voids increases and mechanical strength decreases with the increase of water-to-solid ratio (W/S). Nevertheless pastes with the same material proportions containing different metals show different mechanical strength values. The hydration products were analyzed by XRD. With the increase of water content not previously reported hydration compound was detected: bobierrite.

Analyzing near infrared scattering from human skin to monitor changes in hematocrit

NASA Astrophysics Data System (ADS)

Chaiken, Joseph; Deng, Bin; Goodisman, Jerry; Shaheen, George; Bussjager, R. J.

2012-01-01

The leading preventable cause of death, world-wide, civilian or military, for all people between the ages of 18-45 is undetected internal hemorrhage. Autonomic compensation mechanisms mask changes such as e.g. hematocrit fluctuations that could give early warning if only they could be monitored continuously with reasonable degrees of precision and relative accuracy. Probing tissue with near infrared radiation (NIR) simultaneously produces remitted fluorescence and Raman scattering (IE) plus Rayleigh/Mie light scattering (EE) that noninvasively give chemical and physical information about the materials and objects within. We model tissue as a three-phase system: plasma and red blood cell (RBC) phases that are mobile and a static tissue phase. In vivo, any volume of tissue naturally experiences spatial and temporal fluctuations of blood plasma and RBC content. Plasma and RBC fractions may be discriminated from each other on the basis of their physical, chemical and optical properties. Thus IE and EE from NIR probing yield information about these fractions. Assuming there is no void volume in viable tissue, or that void volume is constant, changes in plasma and RBC volume fractions may be calculated from simultaneous measurements of the two observables, EE and IE. In a previously published analysis we showed the underlying phenomenology but did not provide an algorithm for calculating volume fractions from experimental data. Here we present a simple analysis that allows continuous monitoring of fluid fraction and hematocrit (Hct) changes by measuring IE and EE, and apply it to some experimental in vivo measurements.

The International Space Station Urine Monitoring System (UMS)

NASA Technical Reports Server (NTRS)

Feeback, Daniel L.; Cibuzar, Branelle R.; Milstead, Jeffery R.; Pietrzyk,, Robert A.; Clark, Mark S.F.

2009-01-01

A device capable of making in-flight volume measurements of single void urine samples, the Urine Monitoring System (UMS), was developed and flown on seven U.S. Space Shuttle missions. This device provided volume data for each urine void from multiple crewmembers and allowed samples of each to be taken and returned to Earth for post-flight analysis. There were a number of design flaws in the original instrument including the presence of liquid carry-over producing invalid "actual" micturition volumes and cross-contamination between successive users from residual urine in "dead" spots". Additionally, high or low volume voids could not be accurately measured, the on-orbit calibration and nominal use sequence was time intensive, and the unit had to be returned and disassembled to retrieve the volume data. These problems have been resolved in a new version, the International Space Station (ISS) UMS, that has been designed to provide real-time in-flight volume data with accuracy and precision equivalent to measurements made on Earth and the ability to provide urine samples that are unadulterated by the device. Originally conceived to be interfaced with a U.S.-built Waste Collection System (WCS), the unit now has been modified to interface with the Russian-supplied Sanitary Hygiene Device (ASY). The ISS UMS provides significant advantages over the current method of collecting urine samples into Urine Collection Devices (UCDs), from which samples are removed and returned to Earth for analyses. A significant future advantage of the UMS is that it can provide an interface to analytical instrumentation that will allow real-time measurement of urine bioanalytes allowing monitoring of crewmember health status during flight and the ability to provide medical interventions based on the results of these measurements. Currently, the ISS UMS is scheduled to launch along with Node-3 on STS-130 (20A) in December 2009. UMS will be installed and scientific/functional verification completed prior to placing the instrument into operation. Samples collected during the verification sequence will be returned for analyses on STS-131 (19A) currently scheduled for launch in March 2010. The presence of a UMS on ISS will provide the capability to conduct additional collaborative human life science investigations among the ISS International Partners.

Accurate Characterization of the Pore Volume in Microporous Crystalline Materials

PubMed Central

2017-01-01

Pore volume is one of the main properties for the characterization of microporous crystals. It is experimentally measurable, and it can also be obtained from the refined unit cell by a number of computational techniques. In this work, we assess the accuracy and the discrepancies between the different computational methods which are commonly used for this purpose, i.e, geometric, helium, and probe center pore volumes, by studying a database of more than 5000 frameworks. We developed a new technique to fully characterize the internal void of a microporous material and to compute the probe-accessible and -occupiable pore volume. We show that, unlike the other definitions of pore volume, the occupiable pore volume can be directly related to the experimentally measured pore volumes from nitrogen isotherms. PMID:28636815

Accurate Characterization of the Pore Volume in Microporous Crystalline Materials

DOE PAGES

Ongari, Daniele; Boyd, Peter G.; Barthel, Senja; ...

2017-06-21

Pore volume is one of the main properties for the characterization of microporous crystals. It is experimentally measurable, and it can also be obtained from the refined unit cell by a number of computational techniques. In this work, we assess the accuracy and the discrepancies between the different computational methods which are commonly used for this purpose, i.e, geometric, helium, and probe center pore volumes, by studying a database of more than 5000 frameworks. We developed a new technique to fully characterize the internal void of a microporous material and to compute the probe-accessible and -occupiable pore volume. Lasty, wemore » show that, unlike the other definitions of pore volume, the occupiable pore volume can be directly related to the experimentally measured pore volumes from nitrogen isotherms.« less

Investigation of the Performance of D 2O-Cooled High-Conversion Reactors for Fuel Cycle Calculations

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

Hiruta, Hikaru; Youinou, Gilles

2013-09-01

This report presents FY13 activities for the analysis of D 2O cooled tight-pitch High-Conversion PWRs (HCPWRs) with U-Pu and Th-U fueled cores aiming at break-even or near breeder conditions while retaining the negative void reactivity. The analyses are carried out from several aspects which could not be covered in FY12 activities. SCALE 6.1 code system is utilized, and a series of simple 3D fuel pin-cell models are developed in order to perform Monte Carlo based criticality and burnup calculations. The performance of U-Pu fueled cores with axial and internal blankets is analyzed in terms of their impact on the relativemore » fissile Pu mass balance, initial Pu enrichment, and void coefficient. In FY12, Pu conversion performances of D 2O-cooled HCPWRs fueled with MOX were evaluated with small sized axial/internal DU blankets (approximately 4cm of axial length) in order to ensure the negative void reactivity, which evidently limits the conversion performance of HCPWRs. In this fiscal year report, the axial sizes of DU blankets are extended up to 30 cm in order to evaluate the amount of DU necessary to reach break-even and/or breeding conditions. Several attempts are made in order to attain the milestone of the HCPWR designs (i.e., break-even condition and negative void reactivity) by modeling of HCPWRs under different conditions such as boiling of D 2O coolant, MOX with different 235U enrichment, and different target burnups. A similar set of analyses are performed for Th-U fueled cores. Several promising characteristics of 233U over other fissile like 239Pu and 235U, most notably its higher fission neutrons per absorption in thermal and epithermal ranges combined with lower ___ in the fast range than 239Pu allows Th-U cores to be taller than MOX ones. Such an advantage results in 4% higher relative fissile mass balance than that of U-Pu fueled cores while retaining the negative void reactivity until the target burnup of 51 GWd/t. Several other distinctions between U-Pu and Th-U fueled cores are identified by evaluating the sensitivity coefficients of keff, mass balance, and void coefficient. The effect of advanced iron alloy cladding (i.e., FeCrAl) on the performance of Pu conversion in MOX fueled cores is studied instead of using standard stainless-steel cladding. Variations in clad thickness and coolant-to-fuel volume ratio are also exercised. The use of FeCrAl instead of SS as a cladding alloy reduces the required Pu enrichment and improves the Pu conversion rate primarily due to the absence of nickel in the cladding alloy that results in the reduction of the neutron absorption. Also the difference in void coefficients between SS and FeCrAl alloys is nearly 500 pcm over the entire burnup range. The report also shows sensitivity and uncertainty analyses in order to characterize D 2O cooled HCPWRs from different aspects. The uncertainties of integral parameters (keff and void coefficient) for selected reactor cores are evaluated at different burnup points in order to find similarities and trends respect to D 2O-HCPWR.« less

Large-Scale Reactive Atomistic Simulation of Shock-induced Initiation Processes in Energetic Materials

NASA Astrophysics Data System (ADS)

Thompson, Aidan

2013-06-01

Initiation in energetic materials is fundamentally dependent on the interaction between a host of complex chemical and mechanical processes, occurring on scales ranging from intramolecular vibrations through molecular crystal plasticity up to hydrodynamic phenomena at the mesoscale. A variety of methods (e.g. quantum electronic structure methods (QM), non-reactive classical molecular dynamics (MD), mesoscopic continuum mechanics) exist to study processes occurring on each of these scales in isolation, but cannot describe how these processes interact with each other. In contrast, the ReaxFF reactive force field, implemented in the LAMMPS parallel MD code, allows us to routinely perform multimillion-atom reactive MD simulations of shock-induced initiation in a variety of energetic materials. This is done either by explicitly driving a shock-wave through the structure (NEMD) or by imposing thermodynamic constraints on the collective dynamics of the simulation cell e.g. using the Multiscale Shock Technique (MSST). These MD simulations allow us to directly observe how energy is transferred from the shockwave into other processes, including intramolecular vibrational modes, plastic deformation of the crystal, and hydrodynamic jetting at interfaces. These processes in turn cause thermal excitation of chemical bonds leading to initial chemical reactions, and ultimately to exothermic formation of product species. Results will be presented on the application of this approach to several important energetic materials, including pentaerythritol tetranitrate (PETN) and ammonium nitrate/fuel oil (ANFO). In both cases, we validate the ReaxFF parameterizations against QM and experimental data. For PETN, we observe initiation occurring via different chemical pathways, depending on the shock direction. For PETN containing spherical voids, we observe enhanced sensitivity due to jetting, void collapse, and hotspot formation, with sensitivity increasing with void size. For ANFO, we examine the effect of reaction rates on shock direction, fuel oil fraction, and crystal/fuel oil/void microstructural arrangement. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Dept. of Energy's National Nuclear Security Admin. under contract DEAC0494AL85000.

Investigation of nanoscale voids in Sb-doped p-type ZnO nanowires.

PubMed

Pradel, Ken C; Uzuhashi, Jun; Takei, Toshiaki; Ohkubo, Tadakatsu; Hono, Kazuhiro; Fukata, Naoki

2018-08-17

While it has multiple advantageous optoelectronic and piezoelectric properties, the application of zinc oxide has been limited by the lack of a stable p-type dopant. Recently, it was discovered that antimony doping can lead to stable p-type doping in ZnO, but one curious side effect of the doping process is the formation of voids inside the nanowire. While previously used as a signifier of successful doping, up until now, little research has been performed on these structures themselves. In this work, the effect of annealing on the size and microstructure of the voids was investigated using TEM and XRD, finding that the voids form around a region of Zn 7 Sb 2 O 12 . Furthermore, using Raman spectroscopy, a new peak associated with successful doping was identified. The most surprising finding, however, was the presence of water trapped inside the nanowire, showing that this is actually a composite structure. Water was initially discovered in the nanowires using atom probe tomography, and verified using Raman spectroscopy.

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

Larsen, Michael B.; Van Horn, J. David; Wu, Fei

The synthesis of microporous polymers generally requires postpolymerization modification via hyper-cross-linking to trap the polymeric network in a state with high void volume. An alternative approach utilizes rigid, sterically demanding monomers to inhibit efficient packing, thus leading to a high degree of free volume between polymer side groups and main chains. Herein we combine polymers of intrinsic microporosity with polymerization-induced microphase separation (PIMS), a versatile methodology for the synthesis of nanostructured materials that can be rendered mesoporous. Copolymerization of various styrenic monomers with divinylbenzene in the presence of a poly(lactide) terminated with a chain-transfer agent (PLA-CTA) results in kinetic trappingmore » of a microphase-separated state. Subsequent etching of PLA provides a bicontinuous mesoporous network. Using equilibrium and kinetic nitrogen sorption experiments as well as positron annihilation lifetime spectroscopy (PALS), we demonstrate that variations in the steric characteristics of the styrenic monomer impart the network with microporosity, resulting in hierarchically (meso and micro) porous materials. Additionally, structure–property relationships of the styrenic monomer with total surface area and pore volume indicate that the glass transition temperature (Tg) of the corresponding styrenic homopolymers provides a reasonable measure of the steric interactions and resultant microporosity in these systems. Finally, PALS provides insight into micro- and mesoscopic void volume differences between porous monoliths containing either tert-butyl or TMS-modified styrenic monomers compared to the parent, unmodified styrene.« less

Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

DOE PAGES

Shao, Lin; Wei, C. -C.; Gigax, J.; ...

2014-06-10

Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed notmore » to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.« less

Effect of voids in grouted, post-tensioned concrete bridge construction : volume 2--inspection, repair, materials, and risks.

DOT National Transportation Integrated Search

2009-09-01

Post-tensioned (PT) bridges are major structures that carry significant traffic. These bridges are designed and : constructed because they are economical for spanning long distances. In Texas, there are several signature PT : bridges. In the late 199...

A Mechanical, Microstructural, and Damage Study of Various Tailor Hot Stamped Material Conditions Consisting of Martensite, Bainite, Ferrite, and Pearlite

NASA Astrophysics Data System (ADS)

Bardelcik, Alexander; Vowles, Caryn J.; Worswick, Michael J.

2018-04-01

This paper examines the mechanical, microstructural, and damage characteristics of five different material conditions that were created using the tailored hot stamping process with in-die heating. The tailored material conditions, TMC1 to TMC5 (softest-hardest), were created using die temperatures ranging from 700 °C to 400 °C, respectively. The tensile strength (and total elongation) ranged from 615 MPa (0.24) for TMC1 to 1122 MPa (0.11) for TMC5. TMC3 and TMC4 exhibited intermediate strength levels, with almost no increase in total elongation relative to TMC5. FE-SEM microscopy was used to quantify the mixed-phase microstructures, which ranged in volume fractions of ferrite, pearlite, bainite, and martensite. High-resolution optical microscopy was used to quantify void accumulation and showed that the total void area fraction at 0.60 thickness strain was low for TMC1 and TMC5 ( 0.09 pct) and highest for TMC3 (0.31 pct). Damage modes were characterized and revealed that the poor damage behavior of TMC3 (martensite/bainite/ferrite composition) was a result of small martensitic grains forming at grain boundaries and grain boundary junctions, which facilitated void nucleation as shown by the highest measured void density for this particular material condition. The excellent ductility of TMC1 was a result of a large grained ferritic/pearlitic microstructure that was less susceptible to void nucleation and growth. Large titanium nitride (TiN) inclusions were observed in all of the tailored material conditions and it was shown that they noticeably contributed to the total void accumulation, specifically for the TMC3 and TMC4 material conditions.

α1-Blockers for the treatment of recurrent urinary tract infections in women with dysfunctional voiding: a prospective randomized study.

PubMed

Minardi, Daniele; Pellegrinelli, Francesco; Conti, Alessandro; Fontana, Donatella; Mattia, Michela; Milanese, Giulio; Muzzonigro, Giovanni

2015-01-01

To evaluate the therapeutic effects of tamsulosin on recurrent urinary tract infections in women with dysfunctional voiding. A total of 155 women with recurrent urinary tract infections and dysfunctional voiding were included and randomly assigned to the following groups: uroflowmetry biofeedback (group 1), α1-adrenoceptor antagonists (group 2), uroflowmetry biofeedback combined with α1-adrenoceptor antagonists (group 3) and no treatment (group 4). Patients were evaluated by the American Urological Association Symptom Index at 3, 6 and 12 months. Urodynamics was carried out in patients of groups 1, 2, and 3 at 3, 6 and 12 months, whereas urodynamics was only carried out at 12 months in group 4. All patients were followed up for 1 year with monthly urine cultures. The incidence of storage and emptying symptoms decreased significantly at 3, 6 and 12 months. Mean flow rate, flow time and voiding volume increased significantly (with a better outcome in patients of group 3), whereas post-void residual urine decreased. Mean opening detrusor pressure and detrusor pressure at maximum flow decreased significantly (with a better outcome in patients of group 3). Mean urethral closure pressure and maximum urethral closure pressure decreased significantly with a more significant decrease for patients in group 3. The prevalence of urinary tract infection decreased significantly in all groups after treatment, and this decrease remained stable during the follow up. In women with dysfunctional voiding and recurrent urinary tract infection, tamsulosin associated with uroflowmetry biofeedback might be an effective and safe treatment option for improving urinary symptoms and quality of life. © 2014 The Japanese Urological Association.

Correlation of thermocouple data with voiding function after prostate cryoablation.

PubMed

Levy, David A

2010-02-01

To identify possible correlations of thermocouple recorded data with altered postoperative voiding function after prostate cryosurgery. A retrospective analysis of the records of 58 patients treated with prostate cryoablation from October 2005 through April 2009 was conducted. Multivariate analysis of patient age, presenting prostate-specific antigen level, Gleason score, clinical T stage, prostate volume, maximum low temperature thermocouple recordings, history of radiation and or hormonal therapy, were studied as possible correlative factors for altered postoperative voiding function. Of 58 patients, 22 (37.9%) manifested postcryoablation urgency and frequency (n = 13) requiring medical therapy or retention (n = 9). On multivariate analysis, age (P = .037) and an external sphincter temperature < or = 23 degrees C (P = .012) were associated with voiding frequency, urgency, or retention (odds ratio = 6.26, 95% CI: 1.62-24.16), whereas anterior rectal wall temperature (Denon) was weakly associated (P = .079). Thermocouple data provide an objective means of assessing cryosurgical outcomes. This is the first report of a correlation of such data to post-treatment voiding function. A total of 37.9% of patients experienced urgency and/or frequency or urinary retention after cryoablation of the prostate for localized disease. Older age and external sphincter temperature < or = 23 degrees C were statistically significant predictors of these events. The data suggest that limiting the degree of freezing at the external sphincter may decrease procedure related morbidity. Further study is warranted to better delineate temperature-related data on treatment outcomes. 2010 Elsevier Inc. All rights reserved.

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

Applegate, Matthew B.; Alonzo, Carlo; Georgakoudi, Irene

High resolution three-dimensional voids can be directly written into transparent silk fibroin hydrogels using ultrashort pulses of near-infrared (NIR) light. Here, we propose a simple finite-element model that can be used to predict the size and shape of individual features under various exposure conditions. We compare predicted and measured feature volumes for a wide range of parameters and use the model to determine optimum conditions for maximum material removal. The simplicity of the model implies that the mechanism of multiphoton induced void creation in silk is due to direct absorption of light energy rather than diffusion of heat or othermore » photoproducts, and confirms that multiphoton absorption of NIR light in silk is purely a 3-photon process.« less

Shock wave induced damage of a protein by void collapse

DOE PAGES

Lau, Edmond Y.; Berkowitz, Max L.; Schwegler, Eric R.

2016-01-05

In this study, we report on a series of molecular dynamics simulations that were used to examine the effects of shockwaves on a membrane bound ion channel. A planar shockwave was found to compress the ion channel upon impact but the protein geometry resembles the initial structure as soon as the solvent density begins to dissipate. When a void was placed in close proximity to the membrane, the shockwave proved to be much more destructive to the protein due to formation of a nanojet that results from the asymmetric collapse of the void. The nanojet was able to cause significantmore » structural changes to the protein even at low particle velocities that are not able to directly cause poration of the membrane.« less

Dose Reconstruction of Di-2-Ethylhexyl Phthalate Using a Simple Pharmacokinetic Model [Manuscript

EPA Science Inventory

Background In 2005, eight adults provided full volumes and times of urine voids during one normal work week. These samples were analyzed for four di-2-ethylhexyl phthalate (DEHP) metabolites. Participants also provided diary information on their diet, driving, and out¬door a...

Effect of voids in grouted, post-tensioned concrete bridge construction : volume 1--electrochemical testing and reliability assessment.

DOT National Transportation Integrated Search

2009-09-01

Post-tensioned (PT) bridges are major structures that carry significant traffic. PT bridges are economical for spanning long distances. : In Texas, there are several signature PT bridges. In the late 1990s and early 2000s, several state highway agenc...

Pick-off annihilation of positronium in matter using full correlation single particle potentials: solid He.

PubMed

Zubiaga, A; Tuomisto, F; Puska, M J

2015-01-29

We investigate the modeling of positronium (Ps) states and their pick-off annihilation trapped at open volumes pockets in condensed molecular matter. Our starting point is the interacting many-body system of Ps and a He atom because it is the smallest entity that can mimic the energy gap between the highest occupied and lowest unoccupied molecular orbitals of molecules, and yet the many-body structure of the HePs system can be calculated accurately enough. The exact-diagonalization solution of the HePs system enables us to construct a pairwise full-correlation single-particle potential for the Ps-He interaction, and the total potential in solids is obtained as a superposition of the pairwise potentials. We study in detail Ps states and their pick-off annihilation rates in voids inside solid He and analyze experimental results for Ps-induced voids in liquid He obtaining the radii of the voids. More importantly, we generalize our conclusions by testing the validity of the Tao-Eldrup model, widely used to analyze ortho-Ps annihilation measurements for voids in molecular matter, against our theoretical results for the solid He. Moreover, we discuss the influence of the partial charges of polar molecules and the strength of the van der Waals interaction on the pick-off annihilation rate.

The formation of microvoids in MgO by helium ion implantation and thermal annealing

NASA Astrophysics Data System (ADS)

van Veen, A.; Schut, H.; Fedorov, A. V.; Labohm, F.; Neeft, E. A. C.; Konings, R. J. M.

1999-01-01

The formation of microvoids in metal oxides by helium implantation and thermal annealing is observed under similar conditions as has been shown earlier for silicon. Cleaved MgO (1 0 0) single crystals were implanted with 30 keV 3He ions with doses varying from 10 15 to 10 16 cm -2 and subsequently thermally annealed from RT to 1500 K. Monitoring of the defect depth profile and the retained amount of helium was performed by positron beam analysis and neutron depth profiling, respectively. For a dose larger than 2 × 10 15 cm -2 annealing of the defects was observed in two stages: at 1000 K helium filled monovacancies dissociated, and other defects still retaining the helium were formed, and at 1300 K all helium left the sample while an increase of positron-valence-electron annihilations was observed, indicating an increase of the volume available in the defects. The voids of nm size were located at shallower depth than the implanted helium. At lower dose no voids were left after high temperature annealing. Voids can also be created, and even more effectively, by hydrogen or deuterium implantation. The voids are stable to temperatures of 1500 K. The use of the nanovoids as a precursor state for nanoprecipitates of metals or other species is discussed.

Transcutaneous Electrical Nerve Stimulation in Children with Monosymptomatic Nocturnal Enuresis: A Randomized, Double-Blind, Placebo Controlled Study.

PubMed

Jørgensen, Cecilie Siggaard; Kamperis, Konstantinos; Borch, Luise; Borg, Britt; Rittig, Søren

2017-09-01

In a third of all children with monosymptomatic nocturnal enuresis their condition is refractory to first line treatments. Transcutaneous electrical nerve stimulation has been documented to be efficacious in children with daytime incontinence. We investigated the effect of transcutaneous electrical nerve stimulation in children with monosymptomatic nocturnal enuresis without nocturnal polyuria. Children with monosymptomatic nocturnal enuresis (3 or more wet nights per week) and no nocturnal polyuria were randomized to treatment with active or sham transcutaneous electrical nerve stimulation involving 1-hour sessions twice daily for 10 weeks in a double-blind design. Of the 52 children with monosymptomatic nocturnal enuresis included in the study 47 completed treatment (mean age 9.5 ± 2.1 years, 38 males). None of the children experienced a full response with complete remission of enuresis. Treatment with transcutaneous electrical nerve stimulation did not lead to significant changes in number of wet nights, nocturnal urine production on wet or dry nights, maximum voided volume with and without first morning voided volume, or voiding frequency when comparing parameters before and after treatment. The present study demonstrates no anti-enuretic effect of transcutaneous electrical nerve stimulation in children with monosymptomatic nocturnal enuresis without nocturnal polyuria. Nocturnal urine production and bladder capacity remained unchanged during and after treatment with transcutaneous electrical nerve stimulation. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

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

Moutanabbir, O.; Scholz, R.; Goesele, U.

We present a detailed study of the thermal evolution of H ion-induced vacancy related complexes and voids in bulk GaN implanted under ion-cut conditions. By using transmission electron microscopy, we found that the damage band in as-implanted GaN is decorated with a high density of nanobubbles of approx1-2 nm in diameter. Variable energy Doppler broadening spectroscopy showed that this band contains vacancy clusters and voids. In addition to vacancy clusters, the presence of V{sub Ga}, V{sub Ga}-H{sub 2}, and V{sub Ga}V{sub N} complexes was evidenced by pulsed low-energy positron lifetime spectroscopy. Subtle changes upon annealing in these vacancy complexes weremore » also investigated. As a general trend, a growth in open-volume defects is detected in parallel to an increase in both size and density of nanobubbles. The observed vacancy complexes appear to be stable during annealing. However, for temperatures above 450 deg. C, unusually large lifetimes were measured. These lifetimes are attributed to the formation of positronium in GaN. Since the formation of positronium is not possible in a dense semiconductor, our finding demonstrates the presence of sufficiently large open-volume defects in this temperature range. Based on the Tao-Eldrup model, the average lattice opening during thermal annealing was quantified. We found that a void diameter of 0.4 nm is induced by annealing at 600 deg. C. The role of these complexes in the subsurface microcracking is discussed.« less

Is top-down vs bottom-up radiological evaluation after febrile urinary tract infection really less stressful for the child and family? Challenging the dogma.

PubMed

Telli, Onur; Mermerkaya, Murat; Hajiyev, Perviz; Aydogdu, Ozgu; Afandiyev, Faraj; Suer, Evren; Soygur, Tarkan; Burgu, Berk

2015-03-01

We evaluated whether stress levels in children and parents during radiological evaluation after febrile urinary tract infection are really lower using the top-down approach, where (99m)technetium dimercaptosuccinic acid renal scintigraphy is used initially, than the bottom-up approach, where voiding cystourethrography is initially performed and repeated examinations are easier for all. We prospectively evaluated 120 children 3 to 8 years old. Pain ratings were obtained using the Faces Pain Scale-Revised, and conversation during the procedure was evaluated using the Child-Adult Medical Procedure Interaction Scale-Revised by 2 independent observers. To evaluate parental anxiety, the State-Trait Anxiety Inventory form was also completed. Following a documented febrile urinary tract infection children were randomized to the top-down or bottom-up group. A third group of 44 children undergoing repeat voiding cystourethrography and their parents were also evaluated. Child ratings of pain using the Faces Pain Scale-Revised were not significantly different between the top-down group following (99m)technetium dimercaptosuccinic acid renal scintigraphy (2.99 on a scale of 10) and the bottom-up group following voiding cystourethrography (3.21). Also the Faces Pain Scale-Revised was not significantly different in the repeat voiding cystourethrography group (3.35). On the Child-Adult Medical Procedure Interaction Scale-Revised there was negative correlation between child coping and child distress, as well as rate of child distress and adult coping promoting behavior. Parental state anxiety scores were significantly less in the top-down and repeat voiding cystourethrography groups than in the bottom-up group. Although the top-down approach and repeat voiding cystourethrography cause less anxiety for caregivers, these values do not correlate to pain scale in children. This finding might be due to lack of appropriate evaluation tools of pediatric pain and anxiety. However, the theory that the top-down approach is less invasive, and thus less stressful, requires further research. The Child-Adult Medical Procedure Interaction Scale-Revised data indicate that influences in adult-child interaction are bidirectional. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A connectivity-based modeling approach for representing hysteresis in macroscopic two-phase flow properties

DOE PAGES

Cihan, Abdullah; Birkholzer, Jens; Trevisan, Luca; ...

2014-12-31

During CO 2 injection and storage in deep reservoirs, the injected CO 2 enters into an initially brine saturated porous medium, and after the injection stops, natural groundwater flow eventually displaces the injected mobile-phase CO 2, leaving behind residual non-wetting fluid. Accurate modeling of two-phase flow processes are needed for predicting fate and transport of injected CO 2, evaluating environmental risks and designing more effective storage schemes. The entrapped non-wetting fluid saturation is typically a function of the spatially varying maximum saturation at the end of injection. At the pore-scale, distribution of void sizes and connectivity of void space playmore » a major role for the macroscopic hysteresis behavior and capillary entrapment of wetting and non-wetting fluids. This paper presents development of an approach based on the connectivity of void space for modeling hysteretic capillary pressure-saturation-relative permeability relationships. The new approach uses void-size distribution and a measure of void space connectivity to compute the hysteretic constitutive functions and to predict entrapped fluid phase saturations. Two functions, the drainage connectivity function and the wetting connectivity function, are introduced to characterize connectivity of fluids in void space during drainage and wetting processes. These functions can be estimated through pore-scale simulations in computer-generated porous media or from traditional experimental measurements of primary drainage and main wetting curves. The hysteresis model for saturation-capillary pressure is tested successfully by comparing the model-predicted residual saturation and scanning curves with actual data sets obtained from column experiments found in the literature. A numerical two-phase model simulator with the new hysteresis functions is tested against laboratory experiments conducted in a quasi-two-dimensional flow cell (91.4cm×5.6cm×61cm), packed with homogeneous and heterogeneous sands. Initial results show that the model can predict spatial and temporal distribution of injected fluid during the experiments reasonably well. However, further analyses are needed for comprehensively testing the ability of the model to predict transient two-phase flow processes and capillary entrapment in geological reservoirs during geological carbon sequestration.« less

Crack growth and fracture toughness of amorphous Li-Si anodes: Mechanisms and role of charging/discharging studied by atomistic simulations

NASA Astrophysics Data System (ADS)

Khosrownejad, S. M.; Curtin, W. A.

2017-10-01

Fracture is the main cause of degradation and capacity fading in lithiated silicon during cycling. Experiments on the fracture of lithiated silicon show conflicting results, and so mechanistic models can help interpret experiments and guide component design. Here, large-scale K-controlled atomistic simulations of crack propagation (R-curve KI vs. Δa) are performed at LixSi compositions x = 0.5 , 1.0 , 1.5 for as-quenched/relaxed samples and at x = 0.5 , 1.0 for samples created by discharging from higher Li compositions. In all cases, the fracture mechanism is void nucleation, growth, and coalescence. In as-quenched materials, with increasing Li content the plastic flow stress and elastic moduli decrease but void nucleation and growth happen at smaller stress, so that the initial fracture toughness KIc ≈ 1.0 MPa√{ m} decreases slightly but the initial fracture energy JIc ≈ 10.5J/m2 is similar. After 10 nm of crack growth, the fracture toughnesses increase and become similar at KIc ≈ 1.9 MPa√{ m} across all compositions. Plane-strain equi-biaxial expansion simulations of uncracked samples provide complementary information on void nucleation and growth. The simulations are interpreted within the framework of Gurson model for ductile fracture, which predicts JIc = ασy D where α ≃ 1 and D is the void spacing, and good agreement is found. In spite of flowing plastically, the fracture toughness of LixSi is low because voids nucleate within nano-sized distances ahead of the crack (D ≈ 1nm). Scaling simulation results to experimental conditions, reasonable agreement with experimentally-estimated fracture toughnesses is obtained. The discharging process facilitates void nucleation but decreases the flow stress (as shown previously), leading to enhanced fracture toughness at all levels of crack growth. Therefore, the fracture behavior of lithiated silicon at a given composition is not a material property but instead depends on the history of charging/discharging. These findings indicate that the mechanical behavior (flow and fracture) of lithiated Si must be interpreted within a fully rate- and history-dependent framework.

Effectiveness and safety of silodosin in the treatment of lower urinary tract symptoms in patients with benign prostatic hyperplasia: A European phase IV clinical study (SiRE study).

PubMed

Montorsi, Francesco; Gandaglia, Giorgio; Chapple, Christopher; Cruz, Francisco; Desgrandchamps, Francois; Llorente, Carlos

2016-07-01

To assess the benefit-risk balance of silodosin in a real-life setting of benign prostatic hyperplasia patients with lower urinary tract symptoms. A phase IV trial including men aged ≥60 years with a clinical diagnosis of benign prostatic hyperplasia with an International Prostate Symptom Score ≥12 was carried out. Patients received silodosin 8 mg for 24 weeks. The primary end-point was a decrease ≥25% in the total International Prostate Symptom Score. Secondary end-points were: changes in total, storage and voiding, and quality of life International Prostate Symptom Scores; changes in the International Continence Society-male questionnaire; changes in the frequency/volume chart; and satisfaction according to the Patient Perception of Study Medication questionnaire. Treatment-emergent adverse events were recorded. Overall, 1036 patients were enrolled. Of these, 766 patients (77.1%) had a decrease ≥25% in the total International Prostate Symptom Score. The mean total International Prostate Symptom Score, and storage and voiding symptoms subscores decreased from 18.9, 8.1 and 10.8 to 10.6, 4.9 and 5.7. Nocturia decreased from 85.7% to 52.4%. The mean International Prostate Symptom Score quality of life score decreased from 4.0 to 2.2. Half of the patients reported an improvement in the frequency and bothersomeness of the most frequent symptoms reported at baseline (all P < 0.001). A reduction in the number of voids was documented by the frequency/volume chart data. The most common treatment-emergent adverse event was ejaculation failure (185 patients; 17.9%), which led to study discontinuation in 2.4% of patients. Overall, 74.2% of patients were satisfied with the medication. Silodosin improved lower urinary tract symptoms in three out of four patients, including diurnal voiding and storage symptoms, nocturia, and quality of life. This treatment showed a favorable safety profile in this setting. © 2016 The Japanese Urological Association.

Nocturnal Polyuria in Older Women with Urge Urinary Incontinence: Role of Sleep Quality, Time in Bed and Medications Used.

PubMed

Tyagi, Shachi; Perera, Subashan; Clarkson, Becky D; Tadic, Stasa D; Resnick, Neil M

2017-03-01

Nocturia is common and bothersome in older adults, especially those who are also incontinent. Since nocturnal polyuria is a major contributor, we examined factors associated with nocturnal polyuria in this population to identify those possibly amenable to intervention. We analyzed baseline data from 2 previously completed studies of urge urinary incontinence. The studies involved 284 women (mean age ± SD 72.9 ± 7.9 years) who also completed 3-day voiding diaries. Participants with a nocturnal polyuria index greater than 33% were categorized as having nocturnal polyuria (nocturnal polyuria index = nocturnal urinary volume per 24-hour urine volume). Associations between nocturnal polyuria and various demographic, clinical and sleep related parameters were determined. Overall 55% of the participants had nocturnal polyuria. Multivariable regression analysis revealed that age, body mass index, use of angiotensin converting enzyme inhibitor/angiotensin receptor blocker, time spent in bed and duration of first uninterrupted sleep were independent correlates of nocturnal polyuria. Participants with a larger nocturnal excretion reported a shorter duration of uninterrupted sleep before first awakening to void and worse sleep quality despite spending similar time in bed. Body mass index, use of angiotensin converting enzyme inhibitor/angiotensin receptor blockers, time in bed and duration of uninterrupted sleep before first awakening to void are independently associated with nocturnal polyuria in older women with urge urinary incontinence, and are potentially modifiable. These findings also confirm the association between sleep and nocturnal polyuria. Further studies should explore whether interventions to reduce nocturnal polyuria and/or increase the duration of uninterrupted sleep before first awakening to void would help to improve sleep quality in this population and thereby reduce or eliminate the need for sedative hypnotics. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Urinary ATP May Be a Dynamic Biomarker of Detrusor Overactivity in Women with Overactive Bladder Syndrome

PubMed Central

Oliveira, Olga; Ferreira, Sónia; Reis, Maria Júlia; Oliveira, José Carlos; Correia-de-Sá, Paulo

2013-01-01

Background Nowadays, there is a considerable bulk of evidence showing that ATP has a prominent role in the regulation of human urinary bladder function and in the pathophysiology of detrusor overactivity. ATP mediates nonadrenergic-noncholinergic detrusor contractions in overactive bladders. In vitro studies have demonstrated that uroepithelial cells and cholinergic nerves from overactive human bladder samples (OAB) release more ATP than controls. Here, we compared the urinary ATP concentration in samples collected non-invasively from OAB women with detrusor overactivity and age-matched controls. Methods Patients with neurologic diseases, history of malignancy, urinary tract infections or renal impairment (creatinine clearance <70 ml/min) were excluded. All patients completed a 3-day voiding diary, a 24 h urine collection and blood sampling to evaluate creatinine clearance. Urine samples collected during voluntary voids were immediately freeze-preserved for ATP determination by the luciferin-luciferase bioluminescence assay; for comparison purposes, samples were also tested for urinary nerve growth factor (NGF) by ELISA. Results The urinary content of ATP, but not of NGF, normalized to patients’ urine creatinine levels (ATP/Cr) or urinary volume (ATP.Vol) were significantly (P<0.05) higher in OAB women with detrusor overactivity (n = 34) than in healthy controls (n = 30). Significant differences between the two groups were still observed by boosting urinary ATP/Cr content after water intake, but these were not detected for NGF/Cr. In OAB patients, urinary ATP/Cr levels correlated inversely with mean voided volumes determined in a 3-day voiding diary. Conclusion A high area under the receiver operator characteristics (ROC) curve (0.741; 95% CI 0.62–0.86; P<0.001) is consistent with urinary ATP/Cr being a highly sensitive dynamic biomarker for assessing detrusor overactivity in women with OAB syndrome. PMID:23741373

Defining the "normal" postejaculate urinalysis.

PubMed

Mehta, Akanksha; Jarow, Jonathan P; Maples, Pat; Sigman, Mark

2012-01-01

Although sperm have been shown to be present in the postejaculate urinalysis (PEU) of both fertile and infertile men, the number of sperm present in the PEU of the general population has never been well defined. The objective of this study was to describe the semen and PEU findings in both the general and infertile population, in order to develop a better appreciation for "normal." Infertile men (n = 77) and control subjects (n = 71) were prospectively recruited. Exclusion criteria included azoospermia and medications known to affect ejaculation. All men underwent a history, physical examination, semen analysis, and PEU. The urine was split into 2 containers: PEU1, the initial voided urine, and PEU2, the remaining voided urine. Parametric statistical methods were applied for data analysis to compare sperm concentrations in each sample of semen and urine between the 2 groups of men. Controls had higher average semen volume (3.3 ± 1.6 vs 2.0 ± 1.4 mL, P < .001) and sperm concentrations (112 million vs 56.2 million, P = .011), compared with infertile men. The presence of sperm in urine was common in both groups, but more prevalent among infertile men (98.7% vs 88.7%, P = .012), in whom it comprised a greater proportion of the total sperm count (46% vs 24%, P = .022). The majority of sperm present in PEU were seen in PEU1 of both controls (69%) and infertile men (88%). An association was noted between severe oligospermia (<5 million/mL) with low semen volume (<0.5 mL), and significant sperm counts in PEU (<5 million). Although infertile men tend to have a higher proportion of their total sperm in the urine compared with control, there is a large degree of overlap between the 2 populations, making it difficult to identify a specific threshold to define a positive test. Interpretation of a PEU should be directed by whether the number of sperm in the urine could affect subsequent management.

Comparison of the agglomeration behavior of thin metallic films on SiO2

NASA Astrophysics Data System (ADS)

Gadkari, P. R.; Warren, A. P.; Todi, R. M.; Petrova, R. V.; Coffey, K. R.

2005-07-01

The stability of continuous metallic thin films on insulating oxide surfaces is of interest to applications such as semiconductor interconnections and gate engineering. In this work, we report the study of the formation of voids and agglomeration of initially continuous Cu, Au, Ru and Pt thin films deposited on amorphous thermally grown SiO2 surfaces. Polycrystalline thin films having thicknesses in the range of 10-100 nm were ultrahigh vacuum sputter deposited on thermally grown SiO2 surfaces. The films were annealed at temperatures in the range of 150-800 °C in argon and argon+3% hydrogen gases. Scanning electron microscopy was used to investigate the agglomeration behavior, and transmission electron microscopy was used to characterize the microstructure of the as-deposited and annealed films. The agglomeration sequence in all of the films is found to follow a two step process of void nucleation and void growth. However, void growth in Au and Pt thin films is different from Cu and Ru thin films. Residual stress and adhesion were observed to play an important part in deciding the mode of void growth in Au and Pt thin films. Last, it is also observed that the tendency for agglomeration can be reduced by encapsulating the metal film with an oxide overlayer.

Variability in use of voiding cystourethrogram during initial evaluation of infants with congenital hydronephrosis.

PubMed

Vemulakonda, Vijaya M; Chiang, George; Corbett, Sean T

2014-05-01

To identify geographic variability in the imaging of infants with congenital hydronephrosis at initial pediatric urologic evaluation. We performed a retrospective review of infants aged ≤ 12 months with congenital hydronephrosis seen as new patients from October 2010 to September 2011 at 3 regionally diverse pediatric urology practices: University of Virginia Hospital, Rady Children's Hospital, and Children's Hospital Colorado. Primary outcomes measured were the type and number of tests ordered at initial evaluation. Independent variables collected included the following: patient age, location, and initial ultrasound findings. Ultrasound findings were manually extracted from the attending pediatric urologist's clinic note. All other data were automatically extracted from the electronic medical record. Proportions were analyzed using Pearson's goodness of fit and Fisher exact tests. Medians were compared using the Kruskal-Wallis test. Two hundred forty-one patients met the study criteria. Median patient age was 2 months and did not differ across sites. Most patients (64.7%) had Society for Fetal Urology grade 0-2 hydronephrosis; prevalence of high-grade hydronephrosis varied across sites (P = .002). Use of voiding cystourethrography also varied across sites (17.6%-88.9%); this difference persisted when controlling for age and hydronephrosis grade (P <.05). Use of other imaging studies did not significantly differ across sites. Use of screening voiding cystourethrography for infants with congenital hydronephrosis varies across practices. This variation persists when controlling for differences in age and ultrasound findings, suggesting that regional differences in patient demographics, provider/parental preferences, or referral patterns might contribute to practice variations in the evaluation of these patients. Copyright © 2014 Elsevier Inc. All rights reserved.

In situ transmission electron microscopy observation of pulverization of aluminum nanowires and evolution of the thin surface Al2O3 layers during lithiation-delithiation cycles.

PubMed

Liu, Yang; Hudak, Nicholas S; Huber, Dale L; Limmer, Steven J; Sullivan, John P; Huang, Jian Yu

2011-10-12

Lithiation-delithiation cycles of individual aluminum nanowires (NWs) with naturally oxidized Al(2)O(3) surface layers (thickness 4-5 nm) were conducted in situ in a transmission electron microscope. Surprisingly, the lithiation was always initiated from the surface Al(2)O(3) layer, forming a stable Li-Al-O glass tube with a thickness of about 6-10 nm wrapping around the NW core. After lithiation of the surface Al(2)O(3) layer, lithiation of the inner Al core took place, which converted the single crystal Al to a polycrystalline LiAl alloy, with a volume expansion of about 100%. The Li-Al-O glass tube survived the 100% volume expansion, by enlarging through elastic and plastic deformation, acting as a solid electrolyte with exceptional mechanical robustness and ion conduction. Voids were formed in the Al NWs during the initial delithiation step and grew continuously with each subsequent delithiation, leading to pulverization of the Al NWs to isolated nanoparticles confined inside the Li-Al-O tube. There was a corresponding loss of capacity with each delithiation step when arrays of NWs were galvonostatically cycled. The results provide important insight into the degradation mechanism of lithium-alloy electrodes and into recent reports about the performance improvement of lithium ion batteries by atomic layer deposition of Al(2)O(3) onto the active materials or electrodes.

Prostate volume did not affect voiding function improvements in diode laser enucleation of the prostate.

PubMed

Yang, Stephen Shei-Dei; Hsieh, Cheng-Hsing; Chiang, I-Ni; Lin, Chia-Da; Chang, Shang-Jen

2013-03-01

We compared safety and surgical outcomes in patients with different prostate sizes treated with diode laser enucleation of the prostate. From 2008 to 2012 consecutive patients with benign prostatic obstruction undergoing diode laser prostate enucleation at our institution were enrolled for analysis. A single surgeon performed diode laser prostate enucleation with an end firing, continuous wave diode laser (980 nm). Based on preoperative prostate volume on transrectal ultrasound, patients were stratified into 2 groups, including group 1-65 with less than 60 ml and group 2-55 with 60 ml or greater. Baseline and perioperative characteristics, and postoperative surgical outcomes were compared between the 2 groups. A total of 120 men with a mean ± SD age of 70.2 ± 9.0 years were enrolled for analysis. Compared with group 1 patients, those in group 2 had larger mean total prostate volume (85.0 ± 24.6 vs 40.9 ± 10.8 ml), longer mean operative time (117.7 ± 48.2 vs 60.7 ± 25.0 minutes), higher mean retrieved prostate weight (37.3 ± 16.1 vs 12.5 ± 7.3 gm) and a higher mean tissue retrieval ratio (74.4% ± 22.2% vs 58.8% ± 23.2%, p <0.01). There was no significant difference in the postoperative hemoglobin decrease in the 2 groups (median 0.5 vs 0.9 mg/dl, p = 0.11). The rate of temporary postoperative urinary retention after Foley catheter removal was significantly lower in group 2 (15.4% vs 3.6%, p = 0.04). Postoperative improvements in the peak flow rate, post-void residual urine volume and International Prostate Symptom Score were comparable in the 2 groups. Although patients with a larger prostate required significantly longer operative time and laser energy, voiding function improvements and surgical complication rates of diode laser prostate enucleation were comparable in patients with a larger vs smaller prostate. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Electrical properties of Schottky barrier diodes fabricated on (001) β-Ga2O3 substrates with crystal defects

NASA Astrophysics Data System (ADS)

Oshima, Takayoshi; Hashiguchi, Akihiro; Moribayashi, Tomoya; Koshi, Kimiyoshi; Sasaki, Kohei; Kuramata, Akito; Ueda, Osamu; Oishi, Toshiyuki; Kasu, Makoto

2017-08-01

The electrical properties of Schottky barrier diodes (SBDs) on a (001) β-Ga2O3 substrate were characterized and correlated with wet etching-revealed crystal defects below the corresponding Schottky contacts. The etching process revealed etched grooves and etched pits, indicating the presence of line-shaped voids and small defects near the surface, respectively. The electrical properties (i.e., leakage currents, ideality factor, and barrier height) exhibited almost no correlation with the density of the line-shaped voids. This very weak correlation was reasonable considering the parallel positional relation between the line-shaped voids extending along the [010] direction and the (001) basal plane in which the voids are rarely exposed on the initial surface in contact with the Schottky metals. The distribution of small defects and SBDs with unusually large leakage currents showed similar patterns on the substrate, suggesting that these defects were responsible for the onset of fatal leak paths. These results will encourage studies on crystal defect management of (001) β-Ga2O3 substrates for the fabrication of devices with enhanced performance using these substrates.

Void effect analysis of Pb-208 of fast reactors with modified CANDLE burn-up scheme

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

Widiawati, Nina, E-mail: nina-widiawati28@yahoo.com; Su’ud, Zaki, E-mail: szaki@fi.itb.ac.id

Void effect analysis of Pb-208 as coolant of fast reactors with modified candle burn-up scheme has been conducted. Lead cooled fast reactor (LFR) is one of the fourth-generation reactor designs. The reactor is designed with a thermal power output of 500 MWt. Modified CANDLE burn-up scheme allows the reactor to have long life operation by supplying only natural uranium as fuel cycle input. This scheme introducing discrete region, the fuel is initially put in region 1, after one cycle of 10 years of burn up it is shifted to region 2 and region 1 is filled by fresh natural uraniummore » fuel. The reactor is designed for 100 years with 10 regions arranged axially. The results of neutronic calculation showed that the void coefficients ranged from −0.6695443 % at BOC to −0.5273626 % at EOC for 500 MWt reactor. The void coefficients of Pb-208 more negative than Pb-nat. The results showed that the reactors with Pb-208 coolant have better level of safety than Pb-nat.« less

Detrusor after-contraction: a new insight.

PubMed

Valentini, Francoise A; Marti, Brigitte G; Robain, Gilberte; Nelson, Pierre P

2015-01-01

Detrusor after-contractions (DAC) are non-common in adults. Both definition (nothing in ICS reports) and significance (artefact, link with detrusor overactivity (DO) or bladder outlet obstruction (BOO)) remain discussed. Our purpose was to carry out an analysis of the urodynamic parameters during voidings with DAC and, using the VBN model, to simulate pathophysiological conditions able to explain both voiding phase and DAC. From large urodynamic database of patients referred for evaluation of lower urinary tract dysfunction, DAC were observed in 60 patients (5.7%). Criteria for DAC were post-void residual <30mL and increase of detrusor pressure >10cmH(2)O. VBN model was used for analysis of both pressure and flow curves, and simulations of pathophysiological conditions. Onset of DAC (ODAC) occurred when Q=7.3±5.7mL/s and bladder volume=17.9±15.4mL. Urgency-frequency syndrome and urodynamic diagnosis of DO were the more frequent scenarios associated with DAC. ODAC was associated to an inversion of the slope of detrusor pressure curve without any perturbation in flow curve. Among tested pathophysiological hypothesis (great, abnormal, detrusor force, sphincter contraction), none allowed restoring all recorded curves (flow rate, voiding pressure and DAC). No urodynamic characteristic of the first part of voiding is an index of occurrence of DAC. ODAC is a significant phenomenon linked with the bladder collapse. DAC is not associated with BOO but more probably with DO and appears as the result of local conditions in an almost empty bladder (concentration of stresses around a transducer); thus DAC seems of weak clinical significance.

One normal void and residual following MUS surgery is all that is necessary in most patients.

PubMed

Ballard, Paul; Shawer, Sami; Anderson, Colette; Khunda, Aethele

2018-04-01

There is considerable variation worldwide on how the assessment of voiding function is performed following midurethral sling (MUS) surgery. There is potentially a financial cost, and reduction in efficiency when patient discharge is delayed. Using our current practice of two normal void and residual (V&R) readings before discharge, the aim of this retrospective study was to evaluate the likelihood of an abnormal second V&R test if the first V&R test was normal in order to determine if a policy of discharge after only one satisfactory V&R test is reasonable. Data from 400 patients who had had MUS surgery with or without other procedures were collected. Our unit protocol included two consecutive voids of greater than 200 ml with residuals less than 150 ml before discharge. The patients were divided into the following groups: MUS only, MUS plus anterior colporrhaphy (AR) plus any other procedures (MUS/AR), and MUS with any non-AR procedures (MUS+). Complete datasets were available for 335 patients. Once inadequate tests (low volume voids <200 ml) had been excluded (28% overall), the likelihood of an abnormal second V&R test if the first test was normal was 7.1% overall, but 3.6% for MUS, 11.5% for MUS/AR and 8.6% for MUS+. The findings in the MUS-only group indicate that it is probably safe to discharge patients after one satisfactory V&R test, as long as safety measures such as 'open access' are available so that patients have unhindered readmission if problems arise.

Orthotopic sigmoid vs. ileal neobladders in Japanese patients: a comparative assessment of complications, functional outcomes, and quality of life.

PubMed

Miyake, Hideaki; Furukawa, Junya; Sakai, Iori; Muramaki, Mototsugu; Yamashita, Masuo; Inoue, Taka-Aki; Fujisawa, Masato

2013-10-01

To compare the clinical outcomes of sigmoid and ileal neobladders (NBs) created following radical cystectomy. This study included 90 and 144 Japanese patients undergoing radical cystectomy and orthotopic NB reconstruction with a sigmoid and ileal segment, respectively. Postoperative clinical outcomes between the sigmoid and ileal NB groups (SNBG and INBG) were compared. In this series, 110 early and 51 late complications occurred in 71 and 41 patients, respectively; however, there was no significant difference in the incidence of complications between SNBG and INBG. At 1 year postoperatively, there were no significant differences in the proportion of spontaneous voiders and the continence status between these 2 groups; however, despite the lack of significant differences in the maximal flow rate and voided volume, the post-void residual in SNBG was significantly smaller than that in INBG. Voiding functional outcomes at 5 years postoperatively were also obtained from 28 and 49 in SNBG and INBG, respectively. Although there were no significant changes in the functional outcomes in SNBG, the proportion of spontaneous voiders and post-void residual in INBG at 5 years postoperatively were significantly poorer than those at 1 year postoperatively. Furthermore, the postoperative health-related quality of life assessed by a Short-Form 36 survey did not show any significant differences in all 8 scores between these 2 groups. Both types of NB reconstruction resulted in comparatively satisfactory outcomes; however, the voiding function, particularly that on long-term follow-up, in SNBG appeared to be more favorable than that in INBG. Copyright © 2013 Elsevier Inc. All rights reserved.

Sleep Apnea and Circadian Extracellular Fluid Change as Independent Factors for Nocturnal Polyuria.

PubMed

Niimi, Aya; Suzuki, Motofumi; Yamaguchi, Yasuhiro; Ishii, Masaki; Fujimura, Tetsuya; Nakagawa, Tohru; Fukuhara, Hiroshi; Kume, Haruki; Igawa, Yasuhiko; Akishita, Masahiro; Homma, Yukio

2016-10-01

We investigated the relationships among nocturnal polyuria, sleep apnea and body fluid volume to elucidate the pathophysiology of nocturia in sleep apnea syndrome. We enrolled 104 consecutive patients who underwent polysomnography for suspected sleep apnea syndrome. Self-assessed symptom questionnaires were administered to evaluate sleep disorder and lower urinary tract symptoms, including nocturia. Voiding frequency and voided volume were recorded using a 24-hour frequency-volume chart. Body fluid composition was estimated in the morning and at night using bioelectric impedance analysis. Frequency-volume chart data were analyzed in 22 patients after continuous positive airway pressure therapy. Patients with nocturnal polyuria showed a higher apnea-hypopnea index (33.9 vs 24.2, p = 0.03) and a larger circadian change in extracellular fluid adjusted to lean body mass (0.22 vs -0.19, p = 0.019) than those without nocturnal polyuria. These relations were more evident in patients 65 years old or older than in those 64 years or younger. A multivariate linear regression model showed an independent relationship of nocturnal polyuria with the apnea-hypopnea index and the circadian change in extracellular fluid adjusted to lean body mass (p = 0.0012 and 0.022, respectively). Continuous positive airway pressure therapy significantly improved nocturnal polyuria and nocturia only in patients with nocturnal polyuria. This study identified sleep apnea and the circadian change in extracellular fluid as independent factors for nocturnal polyuria. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A theory for predicting composite laminate warpage resulting from fabrication

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1974-01-01

Linear laminate theory is used with the moment-curvature relationship to derive equations for predicting end deflections due to warpage without solving the coupled fourth-order partial differential equations of the plate. Composite micro- and macrohyphenmechanics are used with laminate theory to assess the contribution of factors such as ply misorientation, fiber migration, and fiber and/or void volume ratio nonuniformity on the laminate warpage. Using these equations, it was found that a 1 deg error in the orientation angle of one ply was sufficient to produce warpage end deflection equal to two laminate thicknesses in a 10 inch by 10 inch laminate made from 8 ply Mod-I/epoxy. Using a sensitivity analysis on the governing parameters, it was found that a 3 deg fiber migration or a void volume ratio of three percent in some plies is sufficient to produce laminate warpage corner deflection equal to several laminate thicknesses. Tabular and graphical data are presented which can be used to identify possible errors contributing to laminate warpage and/or to obtain an a priori assessment when unavoidable errors during fabrication are anticipated.

Electrochemical properties of Sn/C nanoparticles fabricated by redox treatment and pulsed wire evaporation method

NASA Astrophysics Data System (ADS)

Song, Ju-Seok; Cho, Gyu-Bong; Ahn, Jou-Hyeon; Cho, Kwon-Koo

2017-09-01

Tin (Sn) based anode materials are the most promising anode materials for lithium-ion batteries due to their high theoretical capacity corresponding to the formation of Li4.4Sn composition (Li4.4Sn, 994 mAh/g). However, the applications of tin based anodes to lithium-ion battery system are generally limited by a large volume change (>260%) during lithiation and delithiation cycle, which causes pulverize and poor cycling stability. In order to overcome this shortcoming, we fabricate a Sn/C nanoparticle with a yolk-shell structure (Sn/void/C) by using pulsed wire evaporation process and oxidation/reduction heat treatment. Sn nanoparticles are encapsulated by a conductive carbon layer with structural buffer that leaves enough room for expansion and contraction during lithium insertion/desertion. We expect that the yolk-shell structure has the ability to accommodate the volume changes of tin and leading to an improved cycle performance. The Sn/Void/C anode with yolk-shell structure shows a high specific capacity of 760 mAh/g after 50 cycles.

Correlation between some thermo-mechanical and physico-chemical properties in multi-component glasses of Se-Te-Sn-Cd system

NASA Astrophysics Data System (ADS)

Kumar, Amit; Mehta, Neeraj

2017-06-01

The glass transition phenomenon is guided by the swift cooling of a melt (glass-forming liquid). Consequently, the glass as a final product consists of a considerable number of micro-voids having the size of the order of atomic and/or molecular sizes. The model of free volume fluctuation helps in describing the diverse physico-chemical properties of amorphous materials (like glasses and polymers). This theory is based on the fraction of fluctuation free frozen at the glass transition temperature and it forms a basis for determination of various significant thermo-mechanical properties. In the present work, Vickers hardness test method is employed that provides useful information concerning the mechanical behavior of brittle solids. The present work emphasizes the results of micro-indentation measurements on recently synthesized novel Se78- x Te20Sn2Cd x glassy system. Basic thermo-mechanical parameters such as micro-hardness, volume ( V h), formation energy ( E h) of micro-voids in the glassy network and modulus of elasticity ( E) have been determined and their variation with glass composition has been investigated.

Free-volume Study in GeS2-Ga2S3-CsCl Chalcohalide Glasses Using Positron Annihilation Technique

NASA Astrophysics Data System (ADS)

Klym, H.; Ingram, A.; Shpotyuk, O.; Szatanik, R.

Positron annihilation lifetime spectroscopy combined with Doppler broadening of annihilation radiation was applied to study free-volume entities in Ge-Ga-S glasses having different amount of CsCl additives. It is shown that the structural changes caused by CsCl additives can be adequately described by positron trapping modes determined within two-state model. The results testify in a favor of rather unchanged nature of corresponding free-volume voids responsible for positron trapping in the studied glasses, when mainly concentration of these traps is a subject to most significant changes with composition.

Ultrasonic sensing of powder densification

NASA Technical Reports Server (NTRS)

Lu, Yichi; Wadley, Haydn N. G.; Parthasarathi, Sanjai

1992-01-01

An independent scattering theory has been applied to the interpretation of ultrasonic velocity measurements made on porous metal samples produced either by a cold or a high-temperature compaction process. The results suggest that the pores in both processes are not spherical, an aspect ration of 1:3 fitting best with the data for low (less than 4 percent) pore volume fractions. For the hot compacted powders, the pores are smooth due to active diffusional processes during processing. For these types of voids, the results can be extended to a pore fraction of 10 percent, at which point voids form an interconnected network that violates the model assumptions. The cold pressed samples are not as well predicted by the theory because of poor particle bonding.

Mathematical modeling of the process of filling a mold during injection molding of ceramic products

NASA Astrophysics Data System (ADS)

Kulkov, S. N.; Korobenkov, M. V.; Bragin, N. A.

2015-10-01

Using the software package Fluent it have been predicted of the filling of a mold in injection molding of ceramic products is of great importance, because the strength of the final product is directly related to the presence of voids in the molding, making possible early prediction of inaccuracies in the mold prior to manufacturing. The calculations were performed in the formulation of mathematical modeling of hydrodynamic turbulent process of filling a predetermined volume of a viscous liquid. The model used to determine the filling forms evaluated the influence of density and viscosity of the feedstock, and the injection pressure on the mold filling process to predict the formation of voids in the area caused by the shape defect geometry.

Investigation of the plastic fracture of high-strength aluminum alloys

NASA Technical Reports Server (NTRS)

Van Stone, R. H.; Merchant, R. H.; Low, J. R., Jr.

1974-01-01

In a study of plastic fracture in five high-strength aluminum alloys (2014, 2024, 2124, 7075, and 7079), it has been shown that fracture toughness is affected primarily by the size and volume fraction of the larger (2 to 10 microms) second-phase particles. Certain of these particles crack at small plastic strains, nucleating voids which, with further plastic strain, coalesce to cause fracture. Not all second-phase particles crack at small plastic strains, and qualitative analysis of those which are primarily responsible for void nucleation shows that they contain iron or silicon or both. This result suggests that a reduction in the iron and silicon impurity content of the alloys should improve fracture toughness without loss of strength.

Cement-based materials' characterization using ultrasonic attenuation

NASA Astrophysics Data System (ADS)

Punurai, Wonsiri

The quantitative nondestructive evaluation (NDE) of cement-based materials is a critical area of research that is leading to advances in the health monitoring and condition assessment of the civil infrastructure. Ultrasonic NDE has been implemented with varying levels of success to characterize cement-based materials with complex microstructure and damage. A major issue with the application of ultrasonic techniques to characterize cement-based materials is their inherent inhomogeneity at multiple length scales. Ultrasonic waves propagating in these materials exhibit a high degree of attenuation losses, making quantitative interpretations difficult. Physically, these attenuation losses are a combination of internal friction in a viscoelastic material (ultrasonic absorption), and the scattering losses due to the material heterogeneity. The objective of this research is to use ultrasonic attenuation to characterize the microstructure of heterogeneous cement-based materials. The study considers a real, but simplified cement-based material, cement paste---a common bonding matrix of all cement-based composites. Cement paste consists of Portland cement and water but does not include aggregates. First, this research presents the findings of a theoretical study that uses a set of existing acoustics models to quantify the scattered ultrasonic wavefield from a known distribution of entrained air voids. These attenuation results are then coupled with experimental measurements to develop an inversion procedure that directly predicts the size and volume fraction of entrained air voids in a cement paste specimen. Optical studies verify the accuracy of the proposed inversion scheme. These results demonstrate the effectiveness of using attenuation to measure the average size, volume fraction of entrained air voids and the existence of additional larger entrapped air voids in hardened cement paste. Finally, coherent and diffuse ultrasonic waves are used to develop a direct relationship between attenuation and water to cement (w/c) ratio. A phenomenological model based on the existence of fluid-filled capillary voids is used to help explain the experimentally observed behavior. Overall this research shows the potential of using ultrasonic attenuation to quantitatively characterize cement paste. The absorption and scattering losses can be related to the individual microstructural elements of hardened cement paste. By taking a fundamental, mechanics-based approach, it should be possible to add additional components such as scattering by aggregates or even microcracks in a systematic fashion and eventually build a realistic model for ultrasonic wave propagation study for concrete.

Surface evolution in bare bamboo-type metal lines under diffusion and electric field effects

NASA Astrophysics Data System (ADS)

Averbuch, Amir; Israeli, Moshe; Nathan, Menachem; Ravve, Igor

2003-07-01

Irregularities such as voids and cracks often occur in bamboo-type metal lines of microelectronic interconnects. They increase the resistance of the circuits, and may even lead to a fatal failure. In this work, we analyze numerically the electromigration of an unpassivated bamboo-type line with pre-existing irregularities in its top surface (also called a grain-void interface). The bamboo line is subjected to surface diffusion forces and external electric fields. Under these forces, initial defects may either heal or become worse. The grain-void interface is considered to be one-dimensional, and the physical formulation of an electromigration and diffusion model results in two coupled, fourth order, one-dimensional time-dependent PDEs, with the boundary conditions imposed at the electrode points and at the triple point, which belongs to two neighboring grains and the void. These equations are discretized by finite differences on a regular grid in space, and by a Runge-Kutta integration scheme in time, and solved simultaneously with a static Laplace equation describing the voltage distribution throughout each grain, when the substrate conductivity is neglected. Since the voltage distribution is required only along an interface line, the two-dimensional discretization of the grain interior is not needed, and the static problem is solved by the boundary element method at each time step. The motion of the interface line is studied for different ratios between diffusion and electric field forces, and for different initial configurations of the grain-void interface. We study plain and tilted contour lines, considering positive and negative tilts with respect to the external electric field, a stepped contour with field lines entering or exiting the 'step', and a number of modifications of the classical Mullins problem of thermal grooving. We also consider a two-grain Mullins problem with a normal and tilted boundary between the grains, examining positive and negative tilts.

Evaluating quantitative 3-D image analysis as a design tool for low enriched uranium fuel compacts for the transient reactor test facility: A preliminary study

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

Kane, J. J.; van Rooyen, I. J.; Craft, A. E.

In this study, 3-D image analysis when combined with a non-destructive examination technique such as X-ray computed tomography (CT) provides a highly quantitative tool for the investigation of a material’s structure. In this investigation 3-D image analysis and X-ray CT were combined to analyze the microstructure of a preliminary subsized fuel compact for the Transient Reactor Test Facility’s low enriched uranium conversion program to assess the feasibility of the combined techniques for use in the optimization of the fuel compact fabrication process. The quantitative image analysis focused on determining the size and spatial distribution of the surrogate fuel particles andmore » the size, shape, and orientation of voids within the compact. Additionally, the maximum effect of microstructural features on heat transfer through the carbonaceous matrix of the preliminary compact was estimated. The surrogate fuel particles occupied 0.8% of the compact by volume with a log-normal distribution of particle sizes with a mean diameter of 39 μm and a standard deviation of 16 μm. Roughly 39% of the particles had a diameter greater than the specified maximum particle size of 44 μm suggesting that the particles agglomerate during fabrication. The local volume fraction of particles also varies significantly within the compact although uniformities appear to be evenly dispersed throughout the analysed volume. The voids produced during fabrication were on average plate-like in nature with their major axis oriented perpendicular to the compaction direction of the compact. Finally, the microstructure, mainly the large preferentially oriented voids, may cause a small degree of anisotropy in the thermal diffusivity within the compact. α∥/α⊥, the ratio of thermal diffusivities parallel to and perpendicular to the compaction direction are expected to be no less than 0.95 with an upper bound of 1.« less

Roles of polyuria and hyperglycemia in bladder dysfunction in diabetes.

PubMed

Xiao, Nan; Wang, Zhiping; Huang, Yexiang; Daneshgari, Firouz; Liu, Guiming

2013-03-01

Diabetes mellitus causes diabetic bladder dysfunction. We identified the pathogenic roles of polyuria and hyperglycemia in diabetic bladder dysfunction in rats. A total of 72 female Sprague-Dawley® rats were divided into 6 groups, including age matched controls, and rats with sham urinary diversion, urinary diversion, streptozotocin induced diabetes mellitus after sham urinary diversion, streptozotocin induced diabetes mellitus after urinary diversion and 5% sucrose induced diuresis after sham urinary diversion. Urinary diversion was performed by ureterovaginostomy 10 days before diabetes mellitus induction. Animals were evaluated 20 weeks after diabetes mellitus or diuresis induction. We measured 24-hour drinking and voiding volumes, and cystometry. Bladders were harvested to quantify smooth muscle, urothelium and collagen. We measured nitrotyrosine and Mn superoxide dismutase in the bladder. Diabetes and diuresis caused increases in drinking and voiding volume, and bladder weight. Bladder weight decreased in the urinary diversion group and the urinary diversion plus diabetes group. The intercontractile interval, voided volume and compliance increased in the diuresis and diabetes groups, decreased in the urinary diversion group and further decreased in the urinary diversion plus diabetes group. Total cross-sectional tissue, smooth muscle and urothelium areas increased in the diuresis and diabetes groups, and decreased in the urinary diversion and urinary diversion plus diabetes groups. As a percent of total tissue area, collagen decreased in the diuresis and diabetes groups, and increased in the urinary diversion and urinary diversion plus diabetes groups. Smooth muscle and urothelium decreased in the urinary diversion and urinary diversion plus diabetes groups. Nitrotyrosine and Mn superoxide dismutase increased in rats with diabetes and urinary diversion plus diabetes. Polyuria induced bladder hypertrophy, while hyperglycemia induced substantial oxidative stress in the bladder, which may have a pathogenic role in late stage diabetic bladder dysfunction. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Evaluating quantitative 3-D image analysis as a design tool for low enriched uranium fuel compacts for the transient reactor test facility: A preliminary study

DOE PAGES

Kane, J. J.; van Rooyen, I. J.; Craft, A. E.; ...

2016-02-05

In this study, 3-D image analysis when combined with a non-destructive examination technique such as X-ray computed tomography (CT) provides a highly quantitative tool for the investigation of a material’s structure. In this investigation 3-D image analysis and X-ray CT were combined to analyze the microstructure of a preliminary subsized fuel compact for the Transient Reactor Test Facility’s low enriched uranium conversion program to assess the feasibility of the combined techniques for use in the optimization of the fuel compact fabrication process. The quantitative image analysis focused on determining the size and spatial distribution of the surrogate fuel particles andmore » the size, shape, and orientation of voids within the compact. Additionally, the maximum effect of microstructural features on heat transfer through the carbonaceous matrix of the preliminary compact was estimated. The surrogate fuel particles occupied 0.8% of the compact by volume with a log-normal distribution of particle sizes with a mean diameter of 39 μm and a standard deviation of 16 μm. Roughly 39% of the particles had a diameter greater than the specified maximum particle size of 44 μm suggesting that the particles agglomerate during fabrication. The local volume fraction of particles also varies significantly within the compact although uniformities appear to be evenly dispersed throughout the analysed volume. The voids produced during fabrication were on average plate-like in nature with their major axis oriented perpendicular to the compaction direction of the compact. Finally, the microstructure, mainly the large preferentially oriented voids, may cause a small degree of anisotropy in the thermal diffusivity within the compact. α∥/α⊥, the ratio of thermal diffusivities parallel to and perpendicular to the compaction direction are expected to be no less than 0.95 with an upper bound of 1.« less

Comparative Three-Dimensional Morphology of Baleen: Cross-Sectional Profiles and Volume Measurements Using CT Images.

PubMed

Jensen, Megan M; Saladrigas, Amalia H; Goldbogen, Jeremy A

2017-11-01

Baleen whales are obligate filter feeders, straining prey-laden seawater through racks of keratinized baleen plates. Despite the importance of baleen to the ecology and natural history of these animals, relatively little work has been done on baleen morphology, particularly with regard to the three-dimensional morphology and structure of baleen. We used computed tomography (CT) scanning to take 3D images of six baleen specimens representing five species, including three complete racks. With these images, we described the three-dimensional shape of the baleen plates using cross-sectional profiles from within the gum tissue to the tip of the plates. We also measured the percentage of each specimen that was composed of either keratinized plate material or was void space between baleen plates, and thus available for seawater flow. Baleen plates have a complex three-dimensional structure with curvature that varies across the anterior-posterior, proximal-distal, and medial-lateral (lingual-labial) axes. These curvatures also vary with location along the baleen rack, and between species. Cross-sectional profiles resemble backwards-facing airfoils, and some specimens display S-shaped, or reflexed, camber. Within a baleen specimen, the intra-baleen void volume correlates with the average bristle diameter for a species, suggesting that essentially, thinner plates (with more space between them for flow) have thinner bristles. Both plate curvature and the relative proportions of plate and void volumes are likely to have implications for the mechanics of mysticete filtration, and future studies are needed to determine the particular functions of these morphological characters. Anat Rec, 300:1942-1952, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

Correlations among void shape distributions, dynamic damage mode, and loading kinetics [Correlations among spall void shape distributions, damage mode and shock loading kinetics

DOE PAGES

Brown, A. D.; Pham, Q.; Fortin, E. V.; ...

2016-11-10

Here, three-dimensional x-ray tomography (XRT) provides a nondestructive technique to characterize the size, shape, and location of damage in dynamically loaded metals. A shape-fitting method comprising the inertia tensors of individual damage sites was applied to study differences of spall damage development in face-centered-cubic (FCC) and hexagonal-closed-packed (HCP) multicrystals and for a suite of experiments on high-purity copper to examine the influence of loading kinetics on the spall damage process. Applying a volume-weighted average to the best-fit ellipsoidal aspect-ratios allows a quantitative assessment for determining the extent of damage coalescence present in a shocked metal. It was found that incipientmore » transgranular HCP spall damage nucleates in a lenticular shape and is heavily oriented along particular crystallographic slip directions. In polycrystalline materials, shape distributions indicate that a decrease in the tensile loading rate leads to a transition to coalesced damage dominance and that the plastic processes driving void growth are time dependent.« less

Synergistic effects of loxoprofen and glycine on the micturition reflex in conscious rats.

PubMed

Fukiya, Yumiko; Yoshizumi, Masaru; Saito, Mikako; Matsumoto-Miyai, Kazumasa; Nimura, Toshie; Kawatani, Masahito

2014-01-01

We examined the inhibitory effects of loxoprofen, a cyclooxygenase inhibitor, and glycine, a major inhibitory neurotransmitter, on the micturition reflex in conscious rats and hypothesized that these drugs would interact synergistically to inhibit micturition. Voiding behaviors were assessed using a metabolic cage. Oral loxoprofen decreased the urinary frequency, and only a high dose(10 mg/kg) significantly reduced the voided volume. With cystometry, intravenous loxoprofen(0.1-3 mg/kg) and glycine (30 and 100 mg/kg) prolonged the intercontraction intervals (ICI) in adose-dependent manner, but did not change the maximum voiding pressure (MVP) in conscious rats. The combination of loxoprofen (3 mg/kg) and glycine (100 mg/kg) strongly prolonged the ICI more than with either drug alone. The lowest dose of loxoprofen (0.1 mg/kg) and glycine(30 mg/kg) did not affect either the ICI or the MVP, but their combination resulted in a significant increase in the ICI. These results suggest that the combined administration of loxoprofen and glycine produced a synergistic inhibitory effect on the micturition reflex.

Radiation-induced swelling of stainless steel.

PubMed

Shewmon, P G

1971-09-10

Significant swelling (1 to 10 percent due to small voids have been found in stainless steel when it is exposed to fast neutron doses less than expected in commercial fast breeder reactors. The main features of this new effect are: (i) the voids are formed by the precipitation of a small fraction of the radiation-produced vacancies; (ii) the voids form primarily in the temperature range 400 degrees to 600 degrees C (750 degrees to 1100 degrees F); and (iii) the volume increases with dose (fluence) at a rate between linear and parabolic. The limited temperature range of void formation can be explained, but the effects of fluence, microstructure, and composition are determined by a competition between several kinetic processes that are not well understood. This swelling does not affect the feasibility or safety of the breeder reactor,but will have a significant impact on the core design and economics of the breeder.Preliminary results indicate that one cannot eliminate the effect,but cold-working,heat treatment, or small changes in composition can reduce the swelling by a factor of 2 or more. Testing is hampered by the fact that several years in EBR-II are required to accumulate the fluence expected in demonstration plants. Heavyion accelerators,which allow damage rates corresponding to much higher fluxes than those found in EBR-II,hold great promise for short-term tests that will indicate the relative effect of the important variables.

Urine Flow Dynamics Through Prostatic Urethra With Tubular Organ Modeling Using Endoscopic Imagery

PubMed Central

Kambara, Yoichi; Yamanishi, Tomonori; Naya, Yukio; Igarashi, Tatsuo

2014-01-01

Voiding dysfunction is common in the aged male population. However, the obstruction mechanism in the lower urinary tract and critical points for obstruction remains uncertain. The aim of this paper was to develop a system to investigate the relationship between voiding dysfunction and alteration of the shape of the prostatic urethra by processing endoscopic video images of the urethra and analyzing the fluid dynamics of the urine stream. A panoramic image of the prostatic urethra was generated from cystourethroscopic video images. A virtual 3-D model of the urethra was constructed using the luminance values in the image. Fluid dynamics using the constructed model was then calculated assuming a static urethra and maximum urine flow rate. Cystourethroscopic videos from 11 patients with benign prostatic hyperplasia were recorded around administration of an alpha-1 adrenoceptor antagonist. The calculated pressure loss through the prostatic urethra in each model corresponded to the prostatic volume, and the improvements of the pressure loss after treatment correlated to the conventional clinical indices. As shown by the proposed method, the shape of the prostatic urethra affects the transporting urine fluid energy, and this paper implies a possible method for detecting critical lesions responsible for voiding dysfunction. The proposed method provides critical information about deformation of the prostatic urethra on voiding function. Detailed differences in the various types of relaxants for the lower urinary tract could be estimated. PMID:27170869

Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. II. Anisotropy in particle shape.

PubMed

Zachary, Chase E; Jiao, Yang; Torquato, Salvatore

2011-05-01

We extend the results from the first part of this series of two papers by examining hyperuniformity in heterogeneous media composed of impenetrable anisotropic inclusions. Specifically, we consider maximally random jammed (MRJ) packings of hard ellipses and superdisks and show that these systems both possess vanishing infinite-wavelength local-volume-fraction fluctuations and quasi-long-range pair correlations scaling as r(-(d+1)) in d Euclidean dimensions. Our results suggest a strong generalization of a conjecture by Torquato and Stillinger [Phys. Rev. E 68, 041113 (2003)], namely, that all strictly jammed saturated packings of hard particles, including those with size and shape distributions, are hyperuniform with signature quasi-long-range correlations. We show that our arguments concerning the constrained distribution of the void space in MRJ packings directly extend to hard-ellipse and superdisk packings, thereby providing a direct structural explanation for the appearance of hyperuniformity and quasi-long-range correlations in these systems. Additionally, we examine general heterogeneous media with anisotropic inclusions and show unexpectedly that one can decorate a periodic point pattern to obtain a hard-particle system that is not hyperuniform with respect to local-volume-fraction fluctuations. This apparent discrepancy can also be rationalized by appealing to the irregular distribution of the void space arising from the anisotropic shapes of the particles. Our work suggests the intriguing possibility that the MRJ states of hard particles share certain universal features independent of the local properties of the packings, including the packing fraction and average contact number per particle.

Study of galaxies in the Lynx-Cancer void - VII. New oxygen abundances

NASA Astrophysics Data System (ADS)

Pustilnik, S. A.; Perepelitsyna, Y. A.; Kniazev, A. Y.

2016-11-01

We present new or improved oxygen abundances (O/H) for the nearby Lynx-Cancer void updated galaxy sample. They are obtained via the SAO 6-m telescope spectroscopy (25 objects), or derived from the Sloan Digital Sky Survey spectra (14 galaxies, of which for seven objects O/H values were unknown). For eight galaxies with detected [O III] λ4363 line, O/H values are derived via the direct (Te) method. For the remaining objects, O/H was estimated via semi-empirical and empirical methods. For all accumulated O/H data for 81 galaxies of this void (with 40 of them derived via Te method), their relation `O/H versus MB' is compared with that for similar late-type galaxies from denser environments (the Local Volume `reference sample'). We confirm our previous conclusion derived for a subsample of 48 objects: void galaxies show systematically reduced O/H for the same luminosity with respect to the reference sample, in average by 0.2 dex, or by a factor of ˜1.6. Moreover, we confirm the fraction of ˜20 per cent of strong outliers, with O/H of two to four times lower than the typical values for the `reference' sample. The new data are consistent with the conclusion on the slower evolution of the main void galaxy population. We obtained Hα velocity for the faint optical counterpart of the most gas-rich (M(H I)/LB = 25) void object J0723+3624, confirming its connection with the respective H I blob. For similar extremely gas-rich dwarf J0706+3020, we give a tentative O/H ˜(O/H)⊙/45. In Appendix A, we present the results of calibration of semi-empirical method by Izotov & Thuan and of empirical calibrators by Pilyugin & Thuan and Yin et al. on the sample of ˜150 galaxies from the literature with O/H measured by Te method.

Partial molar volume of proteins studied by the three-dimensional reference interaction site model theory.

PubMed

Imai, Takashi; Kovalenko, Andriy; Hirata, Fumio

2005-04-14

The three-dimensional reference interaction site model (3D-RISM) theory is applied to the analysis of hydration effects on the partial molar volume of proteins. For the native structure of some proteins, the partial molar volume is decomposed into geometric and hydration contributions using the 3D-RISM theory combined with the geometric volume calculation. The hydration contributions are correlated with the surface properties of the protein. The thermal volume, which is the volume of voids around the protein induced by the thermal fluctuation of water molecules, is directly proportional to the accessible surface area of the protein. The interaction volume, which is the contribution of electrostatic interactions between the protein and water molecules, is apparently governed by the charged atomic groups on the protein surface. The polar atomic groups do not make any contribution to the interaction volume. The volume differences between low- and high-pressure structures of lysozyme are also analyzed by the present method.

Cure Cycle Optimization of Rapidly Cured Out-Of-Autoclave Composites.

PubMed

Dong, Anqi; Zhao, Yan; Zhao, Xinqing; Yu, Qiyong

2018-03-13

Out-of-autoclave prepreg typically needs a long cure cycle to guarantee good properties as the result of low processing pressure applied. It is essential to reduce the manufacturing time, achieve real cost reduction, and take full advantage of out-of-autoclave process. The focus of this paper is to reduce the cure cycle time and production cost while maintaining high laminate quality. A rapidly cured out-of-autoclave resin and relative prepreg were independently developed. To determine a suitable rapid cure procedure for the developed prepreg, the effect of heating rate, initial cure temperature, dwelling time, and post-cure time on the final laminate quality were evaluated and the factors were then optimized. As a result, a rapid cure procedure was determined. The results showed that the resin infiltration could be completed at the end of the initial cure stage and no obvious void could be seen in the laminate at this time. The laminate could achieve good internal quality using the optimized cure procedure. The mechanical test results showed that the laminates had a fiber volume fraction of 59-60% with a final glass transition temperature of 205 °C and excellent mechanical strength especially the flexural properties.

Cure Cycle Optimization of Rapidly Cured Out-Of-Autoclave Composites

PubMed Central

Dong, Anqi; Zhao, Yan; Zhao, Xinqing; Yu, Qiyong

2018-01-01

Out-of-autoclave prepreg typically needs a long cure cycle to guarantee good properties as the result of low processing pressure applied. It is essential to reduce the manufacturing time, achieve real cost reduction, and take full advantage of out-of-autoclave process. The focus of this paper is to reduce the cure cycle time and production cost while maintaining high laminate quality. A rapidly cured out-of-autoclave resin and relative prepreg were independently developed. To determine a suitable rapid cure procedure for the developed prepreg, the effect of heating rate, initial cure temperature, dwelling time, and post-cure time on the final laminate quality were evaluated and the factors were then optimized. As a result, a rapid cure procedure was determined. The results showed that the resin infiltration could be completed at the end of the initial cure stage and no obvious void could be seen in the laminate at this time. The laminate could achieve good internal quality using the optimized cure procedure. The mechanical test results showed that the laminates had a fiber volume fraction of 59–60% with a final glass transition temperature of 205 °C and excellent mechanical strength especially the flexural properties. PMID:29534048

Signatures of the Primordial Universe from Its Emptiness: Measurement of Baryon Acoustic Oscillations from Minima of the Density Field.

PubMed

Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Liang, Yu; Zhao, Cheng; Tao, Charling; Rodríguez-Torres, Sergio; Eisenstein, Daniel J; Gil-Marín, Héctor; Kneib, Jean-Paul; McBride, Cameron; Percival, Will J; Ross, Ashley J; Sánchez, Ariel G; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Zhao, Gong-Bo

2016-04-29

Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.

"Dark energy" in the Local Void

NASA Astrophysics Data System (ADS)

Villata, M.

2012-05-01

The unexpected discovery of the accelerated cosmic expansion in 1998 has filled the Universe with the embarrassing presence of an unidentified "dark energy", or cosmological constant, devoid of any physical meaning. While this standard cosmology seems to work well at the global level, improved knowledge of the kinematics and other properties of our extragalactic neighborhood indicates the need for a better theory. We investigate whether the recently suggested repulsive-gravity scenario can account for some of the features that are unexplained by the standard model. Through simple dynamical considerations, we find that the Local Void could host an amount of antimatter (˜5×1015 M ⊙) roughly equivalent to the mass of a typical supercluster, thus restoring the matter-antimatter symmetry. The antigravity field produced by this "dark repulsor" can explain the anomalous motion of the Local Sheet away from the Local Void, as well as several other properties of nearby galaxies that seem to require void evacuation and structure formation much faster than expected from the standard model. At the global cosmological level, gravitational repulsion from antimatter hidden in voids can provide more than enough potential energy to drive both the cosmic expansion and its acceleration, with no need for an initial "explosion" and dark energy. Moreover, the discrete distribution of these dark repulsors, in contrast to the uniformly permeating dark energy, can also explain dark flows and other recently observed excessive inhomogeneities and anisotropies of the Universe.

An approach for maximizing the smallest eigenfrequency of structure vibration based on piecewise constant level set method

NASA Astrophysics Data System (ADS)

Zhang, Zhengfang; Chen, Weifeng

2018-05-01

Maximization of the smallest eigenfrequency of the linearized elasticity system with area constraint is investigated. The elasticity system is extended into a large background domain, but the void is vacuum and not filled with ersatz material. The piecewise constant level set (PCLS) method is applied to present two regions, the original material region and the void region. A quadratic PCLS function is proposed to represent the characteristic function. Consequently, the functional derivative of the smallest eigenfrequency with respect to PCLS function takes nonzero value in the original material region and zero in the void region. A penalty gradient algorithm is proposed, which initializes the whole background domain with the original material and decreases the area of original material region till the area constraint is satisfied. 2D and 3D numerical examples are presented, illustrating the validity of the proposed algorithm.

Pre-Career Curriculum Guide for Deaf-Blind. Parts I-III.

ERIC Educational Resources Information Center

Carr, LaVernya K.; And Others

The two-volume document provides a pre-career curriculum guide for professionals and teachers working with deaf-blind students. Part 1 contains professionals and teachers working with deaf-blind students. Part I contains introductory information. Pointed out is the void in providing adequate programs for deaf-blind students over the age of 10.…

Effects of densification of precursor pellets on microstructures and critical current properties of YBCO melt-textured bulks

NASA Astrophysics Data System (ADS)

Setoyama, Yui; Shimoyama, Jun-ichi; Motoki, Takanori; Kishio, Kohji; Awaji, Satoshi; Kon, Koichi; Ichikawa, Naoki; Inamori, Satoshi; Naito, Kyogo

2016-12-01

Effects of densification of precursor disks on the density of residual voids and critical current properties for YBCO melt-textured bulk superconductors were systematically investigated. Six YBCO bulks were prepared from precursor pellets with different initial particle sizes of YBa2Cu3Oy (Y123) powder and applied pressures for pelletization. It was revealed that use of finer Y123 powder and consolidation using cold-isostatic-pressing (CIP) with higher pressures result in reduction of residual voids at inner regions of bulks and enhance Jc especially under low fields below the second peak.

Urodynamic function during sleep-like brain states in urethane anesthetized rats.

PubMed

Crook, J; Lovick, T

2016-01-28

The aim was to investigate urodynamic parameters and functional excitability of the periaqueductal gray matter (PAG) during changes in sleep-like brain states in urethane anesthetized rats. Simultaneous recordings of detrusor pressure, external urethral sphincter (EUS) electromyogram (EMG), cortical electroencephalogram (EEG), and single-unit activity in the PAG were made during repeated voiding induced by continuous infusion of saline into the bladder. The EEG cycled between synchronized, high-amplitude slow wave activity (SWA) and desynchronized low-amplitude fast activity similar to slow wave and 'activated' sleep-like brain states. During (SWA, 0.5-1.5 Hz synchronized oscillation of the EEG waveform) voiding became more irregular than in the 'activated' brain state (2-5 Hz low-amplitude desynchronized EEG waveform) and detrusor void pressure threshold, void volume threshold and the duration of bursting activity in the external urethral sphincter EMG were raised. The spontaneous firing rate of 23/52 neurons recorded within the caudal PAG and adjacent tegmentum was linked to the EEG state, with the majority of responsive cells (92%) firing more slowly during SWA. Almost a quarter of the cells recorded (12/52) showed phasic changes in firing rate that were linked to the occurrence of voids. Inhibition (n=6), excitation (n=4) or excitation/inhibition (n=2) was seen. The spontaneous firing rate of 83% of the micturition-responsive cells was sensitive to changes in EEG state. In nine of the 12 responsive cells (75%) the responses were reduced during SWA. We propose that during different sleep-like brain states changes in urodynamic properties occur which may be linked to changing excitability of the micturition circuitry in the periaqueductal gray. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Advances in clinical study of nocturia].

PubMed

Guan, Zhi-chen

2010-08-18

Nocturia is one of the most common reasons for interrupted sleep in general adult population. The condition affects both men and women, with an incidence that increases dramatically with age. Nocturia has a negative impact on quality of life, affecting both morbidity and mortality. International Continence Society (ICS) issued a report of terminology standardization in 2002, in which nocturia is defined as waking during the night at least once to urinate. Nocturia is a common complaint in elderly population. Although most cases of nocturia are assumed to be caused by urologic problems, the interacting effects of aging and sleep on renal and urinary function, in fact, cause nocturia in the elderly. Effective diagnosis of the condition is dependent on a clear understanding of its underlying etiology. Multiple factors may cause nocturia, such as behavioral or environmental factors and pathologic conditions. In general, the causes of nocturia fall into three categories: diurnal polyuria, nocturnal polyuria, and low bladder capacity. Careful evaluation of medications and underlying medical conditions is essential for the proper management of nocturia. A voiding diary is necessary to diagnose the syndrome of nocturnal polyuria, which is a common cause of nocturia. Addressing any underlying conditions that contribute to nocturia is the first step in treating the condition. Lifestyle and behavioral changes may provide benefit in some individuals, but for many cases, pharmacotherapy is the best option. Antimuscarinic agents are first-line therapies for overactive bladder and are often used in the management of nocturia. Current treatment options also include desmopressin, a synthetic analog of arginine vasopressin, which can increase urinary osmolality and decrease total urinary volume. The desmopressin therefore increases the length of time until the first nocturnal void and decreases the number of nocturnal voids, the NUV voided, and the percentage of urine voided at night.

An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

NASA Astrophysics Data System (ADS)

Cooper, A. J.; Smith, R. J.; Sherry, A. H.

2017-05-01

Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

Properties and processing characteristics of low density carbon cloth phenolic composites

NASA Technical Reports Server (NTRS)

Wang, C. Jeff

1993-01-01

Ply-lift and pocketing are two critical anomalies of carbon cloth phenolic composites (CCPC) in rocket nozzle applications. Ply lift occurs at low temperatures when the A/P and in-plane permeabilities of the composite materials are still very low and in-plane porous paths are blocked. Pocketing occurs at elevated temperatures when in-plane permeability is reduced by the A/P compressive stress. The thermostructural response of CCPC in a rapid heating environment involves simultaneous heat, mass, and momentum transfer along with the degradation of phenolic resin in a multiphase system with temperature- and time-dependent material properties as well as dynamic processing conditions. Three temperature regions represent the consequent chemical reactions, material transformations, and property transitions, and provide a quick qualitative method for characterizing the thermostructural behavior of a CCPC. In order to optimize the FM5939 LDCCP (low density carbon cloth phenolic) for the nozzle performance required in the Advanced Solid Rocket Motor (ASRM) program, a fundamental study on LDCCP materials was conducted. The cured composite has a density of 1.0 +/- 0.5 gm/cc which includes 10 to 25 percent void volume. The weight percent of carbon microballoon is low (7-15 percent). However, they account for approximately one third of the volume and historically their percentages have not been controlled very tightly. In addition, the composite properties show no correlation with microballoon weight percent or fiber properties (e.g. fiber density or fiber moisture adsorption capacity). Test results concerning the ply-lift anomaly in the MNASA motor firings were: (1) Steeper ply angle (shorter path lenght) designs minimized/eliminated by lifting, (2) material with higher void volume ply lifted less frequently, (3) materials with high (greater than 9 percent) microballoon content had a higher rate of ply lifting, and (4) LDCCP materials failed at microballoon-resin interfaces. The objectives of this project are: (1) to investigate the effects of carbon microballoon and cabosil fillers as well as fiber heat treatment on plylift-related mechanical properties, (2) to develop a science-based thermostructural process model for the carbon phenolics. The model can be used in the future for the selection of the improved ASRM materials, (3) to develop the micro-failure mechanisms for the ply-lift initiation and propagation processes during the thermoelastic region of phenolic degradation, i.e. postcuring and devolatilization.

Diffusion amid random overlapping obstacles: Similarities, invariants, approximations

PubMed Central

Novak, Igor L.; Gao, Fei; Kraikivski, Pavel; Slepchenko, Boris M.

2011-01-01

Efficient and accurate numerical techniques are used to examine similarities of effective diffusion in a void between random overlapping obstacles: essential invariance of effective diffusion coefficients (Deff) with respect to obstacle shapes and applicability of a two-parameter power law over nearly entire range of excluded volume fractions (ϕ), except for a small vicinity of a percolation threshold. It is shown that while neither of the properties is exact, deviations from them are remarkably small. This allows for quick estimation of void percolation thresholds and approximate reconstruction of Deff (ϕ) for obstacles of any given shape. In 3D, the similarities of effective diffusion yield a simple multiplication “rule” that provides a fast means of estimating Deff for a mixture of overlapping obstacles of different shapes with comparable sizes. PMID:21513372

The Relationship Between Constraint and Ductile Fracture Initiation as Defined by Micromechanical Analyses

NASA Technical Reports Server (NTRS)

Panontin, Tina L.; Sheppard, Sheri D.

1994-01-01

The use of small laboratory specimens to predict the integrity of large, complex structures relies on the validity of single parameter fracture mechanics. Unfortunately, the constraint loss associated with large scale yielding, whether in a laboratory specimen because of its small size or in a structure because it contains shallow flaws loaded in tension, can cause the breakdown of classical fracture mechanics and the loss of transferability of critical, global fracture parameters. Although the issue of constraint loss can be eliminated by testing actual structural configurations, such an approach can be prohibitively costly. Hence, a methodology that can correct global fracture parameters for constraint effects is desirable. This research uses micromechanical analyses to define the relationship between global, ductile fracture initiation parameters and constraint in two specimen geometries (SECT and SECB with varying a/w ratios) and one structural geometry (circumferentially cracked pipe). Two local fracture criteria corresponding to ductile fracture micromechanisms are evaluated: a constraint-modified, critical strain criterion for void coalescence proposed by Hancock and Cowling and a critical void ratio criterion for void growth based on the Rice and Tracey model. Crack initiation is assumed to occur when the critical value in each case is reached over some critical length. The primary material of interest is A516-70, a high-hardening pressure vessel steel sensitive to constraint; however, a low-hardening structural steel that is less sensitive to constraint is also being studied. Critical values of local fracture parameters are obtained by numerical analysis and experimental testing of circumferentially notched tensile specimens of varying constraint (e.g., notch radius). These parameters are then used in conjunction with large strain, large deformation, two- and three-dimensional finite element analyses of the geometries listed above to predict crack initiation loads and to calculate the associated (critical) global fracture parameters. The loads are verified experimentally, and microscopy is used to measure pre-crack length, crack tip opening displacement (CTOD), and the amount of stable crack growth. Results for A516-70 steel indicate that the constraint-modified, critical strain criterion with a critical length approximately equal to the grain size (0.0025 inch) provides accurate predictions of crack initiation. The critical void growth criterion is shown to considerably underpredict crack initiation loads with the same critical length. The relationship between the critical value of the J-integral for ductile crack initiation and crack depth for SECT and SECB specimens has been determined using the constraint-modified, critical strain criterion, demonstrating that this micromechanical model can be used to correct in-plane constraint effects due to crack depth and bending vs. tension loading. Finally, the relationship developed for the SECT specimens is used to predict the behavior of circumferentially cracked pipe specimens.

Estimation of coolant void reactivity for CANDU-NG lattice using DRAGON and validation using MCNP5 and TRIPOLI-4.3

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

Karthikeyan, R.; Tellier, R. L.; Hebert, A.

2006-07-01

The Coolant Void Reactivity (CVR) is an important safety parameter that needs to be estimated at the design stage of a nuclear reactor. It helps to have an a priori knowledge of the behavior of the system during a transient initiated by the loss of coolant. In the present paper, we have attempted to estimate the CVR for a CANDU New Generation (CANDU-NG) lattice, as proposed at an early stage of the Advanced CANDU Reactor (ACR) development. We have attempted to estimate the CVR with development version of the code DRAGON, using the method of characteristics. DRAGON has several advancedmore » self-shielding models incorporated in it, each of them compatible with the method of characteristics. This study will bring to focus the performance of these self-shielding models, especially when there is voiding of such a tight lattice. We have also performed assembly calculations in 2 x 2 pattern for the CANDU-NG fuel, with special emphasis on checkerboard voiding. The results obtained have been validated against Monte Carlo codes MCNP5 and TRIPOLI-4.3. (authors)« less

The optimal duration of frequency-volume charts related to compliance and reliability.

PubMed

van Haarst, Ernst P; Bosch, J L H Ruud

2014-03-01

To assess Frequency-volume charts (FVCs) for the yield of additional recorded days and the ideal duration of recording related to compliance and reliability. Of 500 consecutive urologic outpatients willing to complete a 7-day FVC, 378 FVCs were evaluable. During seven consecutive days every voiding time and volume were recorded. Missed entries were indicated with a coded letter, thereby assessing the true frequency and compliance. Reliability is the agreement of the day-to-day FVC parameters with the 7-day FVC pattern. Single-day reliability was assessed and used in the Spearman-Brown formula. FVCs of 228 male and 150 females were evaluated. Mean age was 55.2 years (standard deviation [SD]: 16.2 years), and mean 24-hr urine production was 1,856 ml (SD: 828 ml). The percentage of patients with complete FVCs decreased from 78% on day 2 to 58% on day 7, and dropped below 70% after 4 days. Single-day reliability was r = 0.63 for nocturnal urine production, r = 0.72 for 24-hr urine production, and r = 0.80 for mean voided volume. At 5 days, reliability of 90% was achieved for all parameters. With each additional day, FVCs showed a decrease in compliance and an increase in reliability. At day 3, reliability of 80% was achieved for all FVC parameters, but compliance dropped to 73%. Beyond 5 days, the yield of additional recorded days was limited. We advocate an FVC duration of 3 days, but the duration may be shortened or extended depending on the goal of the FVC. © 2013 Wiley Periodicals, Inc.

On the effect of hydrostatic pressure on the conformational stability of globular proteins.

PubMed

Graziano, Giuseppe

2015-12-01

The model developed for cold denaturation (Graziano, PCCP 2010, 12, 14245-14252) is extended to rationalize the dependence of protein conformational stability upon hydrostatic pressure, at room temperature. A pressure- volume work is associated with the process of cavity creation for the need to enlarge the liquid volume against hydrostatic pressure. This contribution destabilizes the native state that has a molecular volume slightly larger than the denatured state due to voids existing in the protein core. Therefore, there is a hydrostatic pressure value at which the pressure-volume contribution plus the conformational entropy loss of the polypeptide chain are able to overwhelm the stabilizing gain in translational entropy of water molecules, due to the decrease in water accessible surface area upon folding, causing denaturation. © 2015 Wiley Periodicals, Inc.

Modeling a Possible Volcanic Origin for Interior Layered Deposits on Mars

NASA Astrophysics Data System (ADS)

Chapman, M. G.; Kneissl, T.

2011-12-01

This study was undertaken to examine the valid range of temperatures required for sub-ice volcanic origin of interior layered deposits (ILDs) in Valles Marineris. To this end, using GIS the volume estimates of Ophir Chasma and its 4 ILDs were mapped and measured. The GIS volumes in this study are based on high-res HRSC topography overlain on MOLA. We determined the void space of Ophir Chasma sans ILDs to be 92,319 km3. Volumes for each ILD mound were determined to be 6,185 km3, 4,833 km3, 2,628 km3, and 0.2 km3 (negligible); totaling 13,642 km3. A sub-ice volcano requires eruption beneath an existing ice sheet or ponded ice. If during the formation of a sub-ice volcano the associated unstable englacial meltwater lake is drained by jökulhlaups or if the volcano rises above the meltwater, effused subaerial lava will cap the tuff cone forming resistant sheet lavas. Hence, the lava cap horizon can be used to estimate the minimum height of ice. Three resistant ILD caprock locales (found only on the 2 largest ILDs) were mapped and the hypothetical ice volumes measured beneath their elevations are 77,391 km3, 79,899 km3, and 51,695 km3. Following the equation from Chapman et al. (2003), if the known ILDs in Ophir are assumed to be basaltic subice volcanoes, calorimetry can be used to estimate the volumes of meltwater generated by their eruption [Allen, 1980; Björnsson, 1988; Gudmundsson and Björnsson, 1991; Gudmundsson et al., 1997; Höskuldsson and Sparks, 1997]. These estimates are based on (1) the volume and likely mound density, (2) the heat content of basaltic magmas, and (3) the specific heat capacity and the latent heat of fusion for ice. The ice that can be melted by a mass of magma as it solidifies and cools can be calculated by equating the heat content of the magma with the heat used for melting. Two possible end member cases were used. In the first case it is assumed that the chasma contained ice at its melting point of 273 K and in the other case the present day temperature at the latitude of Juventae Chasma of 150 K [Haberle et al., 1999] is assumed. At 273 K the predicted volume of melted ice = 96,465 km3 exceeds the void volume, so at this temperature it would be fairly impossible for ILD sub-ice edifices to form unless the ice greatly exceeded plateau height. At 150 K, the predicted volume of melted ice = 55,755 km3, and this plus the measured volume of the ILD mounds (13,642 km3) = 69,401 km3 or 22,918 km3 less than the volume of the Ophir void. So, at this temperature sub-ice volcano formation is within the realm of possibility. Also, the equivalent meltwater volume of 51,152 km3 is close to that calculated to lie beneath the lowest caprock height. The additional missing 22,918 km3 may represent loss due to ash escaping the chasma, ILD erosion, and sublimation of remaining ice. In conclusion, modeling indicates that the possibility the ILDs may have been sub-ice volcanoes increases in validity as temperature near 150 K. A sub-ice origin also implies prolonged volcanically-induced hydrothermal systems.

48 CFR 2403.405 - Misrepresentations or violations of the Covenant Against Contingent Fees.

Code of Federal Regulations, 2010 CFR

2010-10-01

... bid or proposal. (2) If after award, enforce the government's right to void the contract or to recover the fee. (3) Initiate suspension or debarment action. (4) Refer suspected fraudulent or criminal...

Functional Magnetic Resonance Imaging with Concurrent Urodynamic Testing Identifies Brain Structures Involved in Micturition Cycle in Patients with Multiple Sclerosis.

PubMed

Khavari, Rose; Karmonik, Christof; Shy, Michael; Fletcher, Sophie; Boone, Timothy

2017-02-01

Neurogenic lower urinary tract dysfunction, which is common in patients with multiple sclerosis, has a significant impact on quality of life. In this study we sought to determine brain activity processes during the micturition cycle in female patients with multiple sclerosis and neurogenic lower urinary tract dysfunction. We report brain activity on functional magnetic resonance imaging and simultaneous urodynamic testing in 23 ambulatory female patients with multiple sclerosis. Individual functional magnetic resonance imaging activation maps at strong desire to void and at initiation of voiding were calculated and averaged at Montreal Neuroimaging Institute. Areas of significant activation were identified in these average maps. Subgroup analysis was performed in patients with elicitable neurogenic detrusor overactivity or detrusor-sphincter dyssynergia. Group analysis of all patients at strong desire to void yielded areas of activation in regions associated with executive function (frontal gyrus), emotional regulation (cingulate gyrus) and motor control (putamen, cerebellum and precuneus). Comparison of the average change in activation between previously reported healthy controls and patients with multiple sclerosis showed predominantly stronger, more focal activation in the former and lower, more diffused activation in the latter. Patients with multiple sclerosis who had demonstrable neurogenic detrusor overactivity and detrusor-sphincter dyssynergia showed a trend toward distinct brain activation at full urge and at initiation of voiding respectively. We successfully studied brain activation during the entire micturition cycle in female patients with neurogenic lower urinary tract dysfunction and multiple sclerosis using a concurrent functional magnetic resonance imaging/urodynamic testing platform. Understanding the central neural processes involved in specific parts of micturition in patients with neurogenic lower urinary tract dysfunction may identify areas of interest for future intervention. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Simplifying the diagnosis of 4 common voiding conditions using uroflow/electromyography, electromyography lag time and voiding history.

PubMed

Van Batavia, Jason P; Combs, Andrew J; Hyun, Grace; Bayer, Agnes; Medina-Kreppein, Daisy; Schlussel, Richard N; Glassberg, Kenneth I

2011-10-01

Noninvasive uroflowmetry with simultaneous electromyography is useful to triage cases of lower urinary tract symptoms into 4 urodynamically defined conditions, especially when incorporating short and long electromyography lag times in the analysis. We determined the prevalence of these 4 conditions at a single referral institution and the usefulness of uroflowmetry with simultaneous electromyography and electromyography lag time to confirm the diagnosis, guide treatment and monitor response. We retrospectively reviewed the records of 100 consecutive normal children who presented with persistent lower urinary tract symptoms, underwent uroflowmetry with electromyography as part of the initial evaluation and were diagnosed with 1 of 4 conditions based on certain uroflowmetry/electromyography features. The conditions included 1) dysfunctional voiding--active pelvic floor electromyography during voiding with or without staccato flow, 2a) idiopathic detrusor overactivity disorder-A--a quiet pelvic floor during voiding and shortened lag time (less than 2 seconds), 2b) idiopathic detrusor overactivity disorder-B--a quiet pelvic floor with a normal lag time, 3) detrusor underutilization disorder--volitionally deferred voiding with expanded bladder capacity but a quiet pelvic floor, and 4) primary bladder neck dysfunction--prolonged lag time (greater than 6 seconds) and a depressed, right shifted uroflowmetry curve with a quiet pelvic floor during voiding. Treatment was tailored to the underlying condition in each patient. The group consisted of 50 males and 50 females with a mean age of 8 years (range 3 to 18). Dysfunctional voiding was more common in females (p <0.05) while idiopathic detrusor overactivity disorder-B and primary bladder neck dysfunction were more common in males (p <0.01). With treatment uroflowmetry parameters normalized for all types. Electromyography lag time increased in idiopathic detrusor overactivity disorder-A cases and decreased in primary bladder neck dysfunction cases. Noninvasive uroflowmetry with simultaneous electromyography offers an excellent alternative to invasive urodynamics to diagnose 4 urodynamically defined conditions. It identifies the most appropriate therapy for the specific condition and objectively monitors the treatment response. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A three-dimensional meso-macroscopic model for Li-Ion intercalation batteries

DOE PAGES

Allu, S.; Kalnaus, S.; Simunovic, S.; ...

2016-06-09

Through this study, we present a three-dimensional computational formulation for electrode-electrolyte-electrode system of Li-Ion batteries. The physical consistency between electrical, thermal and chemical equations is enforced at each time increment by driving the residual of the resulting coupled system of nonlinear equations to zero. The formulation utilizes a rigorous volume averaging approach typical of multiphase formulations used in other fields and recently extended to modeling of supercapacitors [1]. Unlike existing battery modeling methods which use segregated solution of conservation equations and idealized geometries, our unified approach can model arbitrary battery and electrode configurations. The consistency of multi-physics solution also allowsmore » for consideration of a wide array of initial conditions and load cases. The formulation accounts for spatio-temporal variations of material and state properties such as electrode/void volume fractions and anisotropic conductivities. The governing differential equations are discretized using the finite element method and solved using a nonlinearly consistent approach that provides robust stability and convergence. The new formulation was validated for standard Li-ion cells and compared against experiments. Finally, its scope and ability to capture spatio-temporal variations of potential and lithium distribution is demonstrated on a prototypical three-dimensional electrode problem.« less

A New Approach to Automated Labeling of Internal Features of Hardwood Logs Using CT Images

Treesearch

Daniel L. Schmoldt; Pei Li; A. Lynn Abbott

1996-01-01

The feasibility of automatically identifying internal features of hardwood logs using CT imagery has been established previously. Features of primary interest are bark, knots, voids, decay, and clear wood. Our previous approach: filtered original CT images, applied histogram segmentation, grew volumes to extract 3-d regions, and applied a rule base, with Dempster-...

Laboratory and environmental decay of wood–plastic composite boards: flexural properties

Treesearch

Rebecca Ibach; Marek Gnatowski; Grace Sun; Jessie Glaeser; Mathew Leung; John Haight

2017-01-01

The flexural properties of wood–plastic composite (WPC) deck boards exposed to 9.5 years of environmental decay in Hilo, Hawaii, were compared to samples exposed to moisture and decay fungi for 12 weeks in the laboratory, to establish a correlation between sample flexural properties and calculated void volume. Specimens were tested for flexural strength and modulus,...

Rambutan-like FeCO3 hollow microspheres: facile preparation and superior lithium storage performances.

PubMed

Zhong, Yiren; Su, Liwei; Yang, Mei; Wei, Jinping; Zhou, Zhen

2013-11-13

Rambutan-like FeCO3 hollow microspheres were prepared via a facile and economic one-step hydrothermal method. The structure and morphology evolution mechanism was disclosed through time-dependent experiments. After undergoing the symmetric inside-out Ostwald ripening, the resultants formed microporous/nanoporous constructions composed of numerous one-dimensional (1D) nanofiber building blocks. Tested as anode materials of Li-ion batteries, FeCO3 hollow microspheres presented attractive electrochemical performances. The capacities were over 1000 mAh g(-1) for initial charge, ~880 mAh g(-1) after 100 cycles at 50 mA g(-1), and ~710 mAh g(-1) after 200 cycles at 200 mA g(-1). The 1D nanofiber assembly and hollow interior endow this material efficient contact with electrolyte, short Li(+) diffusion paths, and sufficient void spaces to accommodate large volume variation. The cost-efficient FeCO3 with rationally designed nanostructures is a promising anode candidate for Li-ion batteries.

Foliage plants for indoor removal of the primary combustion gases carbon monoxide and nitrogen dioxide

NASA Technical Reports Server (NTRS)

Wolverton, B. C.; Mcdonald, R. C.; Mesick, H. H.

1985-01-01

Foliage plants were evaluated for their ability to sorb carbon monoxide and nitrogen dioxide, the two primary gases produced during the combustion of fossil fuels and tobacco. The spider plant (Chlorophytum elatum var. vittatum) could sorb 2.86 micrograms CO/sq cm leaf surface in a 6 h photoperiod. The golden pothos (Scindapsus aureus) sorbed 0.98 micrograms CO/sq cm leaf surface in the same time period. In a system with the spider plant, greater than or equal to 99 percent of an initial concentration of 47 ppm NO2 could be removed in 6 h from a void volume of approximately 0.35 cu m. One spider plant potted in a 3.8 liter container can sorb 3300 micrograms CO and effect the removal of 8500 micrograms NO2/hour, recognizing the fact that a significant fraction of NO2 at high concentrations will be lost by surface sorption, dissolving in moisture, etc.

Role of Hydrogen and Structure on CMSX-2

NASA Technical Reports Server (NTRS)

Baker, C. L.; Chene, J.; Kromp, W.; Pinczolitis, H.; Bernstein, S. M.; Williams, J. C.

1985-01-01

The goal was to characterize and understand the detailed effect of hydrogen on the tensile and fatigue behavior of single crystals of CMSX-2. Specimens were solutionized, air cooled, and then aged in one of two ways. The resultant macro and microstructure included a pronounced dendritic structure with numerous low angle boundaries in the interdendritic region and on the average a high level of porosity with a large variation in size and distribution. Hydrogen permeability and diffusivity in this material was found to be very low at room temperature. Hydrogen concentration studies on thin samples yielded values significantly higher than found for similar charging conditions in nickel and stainless steels. The tensile mechanical properties were found to depend on hydrogen concentration. SEM observations of the brittle subsurface zone revealed a strong correlation between crack initiation sites and voids just beneath the surface. The hollow and solid samples were compared to better understand the influence of increased charged volume on the fatigue behavior.

Municipal-wastewater treatment using upflow-anaerobic filters.

PubMed

Manariotis, loannis D; Grigoropoulos, Sotirios G

2006-03-01

Three 12.5-L upflow-anaerobic filters (AF), with ceramic-saddle, plastic-ring, and crushed-stone packing, were used to evaluate the sustained treatment of municipal wastewater. The reactors were initially fed dogfood-fortified wastewater and then raw municipal wastewater, and operated at 25.4 degrees C (32 months) and 15.5 degrees C (2 months). During 23 months, the AF units treated municipal wastewater (mean chemical oxygen demand [COD] 442 mg/L and total suspended solids [TSS] 247 mg/L), the hydraulic retention time (HRT) ranged from 3.1 to 0.30 d (empty bed), and the organic loading rate ranged from 0.115 to 1.82 kg COD/m3d. At the higher temperature and an HRT (void volume) of 1.0 d, COD and TSS removals ranged from 74 to 79% and 95 to 96%, respectively; however, efficiencies declined substantially at HRT values less than 0.4 d. Reactor performance, under the same hydraulic and organic loadings, deteriorated with time and was adversely affected by lower temperature.

Nonantimuscarinic treatment for overactive bladder: a systematic review.

PubMed

Olivera, Cedric K; Meriwether, Kate; El-Nashar, Sherif; Grimes, Cara L; Chen, Chi Chiung Grace; Orejuela, Francisco; Antosh, Danielle; Gleason, Jon; Kim-Fine, Shunaha; Wheeler, Thomas; McFadden, Brook; Balk, Ethan M; Murphy, Miles

2016-07-01

The purpose of the study was to determine the efficacy and safety of nonantimuscarinic treatments for overactive bladder. Medline, Cochrane, and other databases (inception to April 2, 2014) were used. We included any study design in which there were 2 arms and an n > 100, if at least 1 of the arms was a nonantimuscarinic therapy or any comparative trial, regardless of number, if at least 2 arms were nonantimuscarinic therapies for overactive bladder. Eleven reviewers double-screened citations and extracted eligible studies for study: population, intervention, outcome, effects on outcome categories, and quality. The body of evidence for categories of interventions were summarized and assessed for strength. Ninety-nine comparative studies met inclusion criteria. Interventions effective to improve subjective overactive bladder symptoms include exercise with heat and steam generating sheets (1 study), diaphragmatic (1 study), deep abdominal (1 study), and pelvic floor muscle training exercises (2 studies). Pelvic floor exercises are more effective in subjective and objective outcomes with biofeedback or verbal feedback. Weight loss with diet and exercise, caffeine reduction, 25-50% reduction in fluid intake, and pelvic floor muscle exercises with verbal instruction and or biofeedback were all efficacious. Botulinum toxin A improves urge incontinence episodes, urgency, frequency, quality of life, nocturia, and urodynamic testing parameters. Acupuncture improves quality of life and urodynamic testing parameters. Extracorporeal magnetic stimulation improves urodynamic parameters. Mirabegron improves daily incontinence episodes, nocturia, number of daily voids, and urine volume per void, whereas solabegron improves daily incontinence episodes. Short-term posterior tibial nerve stimulation is more efficacious than pelvic floor muscle training exercises and behavioral therapy for improving: urgency, urinary incontinence episodes, daily voids, volume per void, and overall quality of life. Sacral neuromodulation is more efficacious than antimuscarinic treatment for subjective improvement of overactive bladder and quality of life. Transvaginal electrical stimulation demonstrates subjective improvement in overactive bladder symptoms and urodynamic parameters. Multiple therapies, including physical therapy, behavioral therapy, botulinum toxin A, acupuncture, magnetic stimulation, mirabegron, posterior tibial nerve stimulation, sacral neuromodulation, and transvaginal electrical stimulation, are efficacious in the treatment of overactive bladder. Copyright © 2016 Elsevier Inc. All rights reserved.

Transcutaneous Electrical Nerve Stimulation Combined with Oxybutynin is Superior to Monotherapy in Children with Urge Incontinence: A Randomized, Placebo Controlled Study.

PubMed

Borch, Luise; Hagstroem, Soeren; Kamperis, Konstantinos; Siggaard, C V; Rittig, Soeren

2017-08-01

We evaluated whether combination therapy with transcutaneous electrical nerve stimulation and oxybutynin results in a superior treatment response compared to either therapy alone in children with urge incontinence. In this placebo controlled study 66 children with a mean ± SD age of 7.3 ± 1.6 years who were diagnosed with urge incontinence were randomized to 3 treatment groups. Group 1 consisted of 22 children undergoing transcutaneous electrical nerve stimulation plus active oxybutynin administration. Group 2 included 21 children undergoing active transcutaneous electrical nerve stimulation plus placebo oxybutynin administration. Group 3 consisted of 23 children undergoing active oxybutynin administration plus placebo transcutaneous electrical nerve stimulation. The children received active or placebo transcutaneous electrical nerve stimulation over the sacral S2 to S3 outflow for 2 hours daily in combination with 5 mg active or placebo oxybutynin twice daily. The intervention period was 10 weeks. Primary outcome was number of wet days weekly. Secondary outcomes were severity of incontinence, frequency, maximum voided volume over expected bladder capacity for age, average voided volume over expected bladder capacity for age and visual analogue scale score. Combination therapy was superior to oxybutynin monotherapy, with an 83% greater chance of treatment response (p = 0.05). Combination therapy was also significantly more effective than transcutaneous electrical nerve stimulation monotherapy regarding reduced number of wet days weekly (mean difference -2.28, CI -4.06 to -0.49), severity of incontinence (-3.11, CI -5.98 to -0.23) and daily voiding frequency (-2.82, CI -4.48 to -1.17). Transcutaneous electrical nerve stimulation in combination with oxybutynin for childhood urge incontinence was superior to monotherapy consisting of transcutaneous electrical nerve stimulation or oxybutynin, although the latter only reached borderline statistical significance. Furthermore, transcutaneous electrical nerve stimulation was associated with a decreased risk of oxybutynin induced post-void residual urine greater than 20 ml. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Numerical study of the influence of geometrical characteristics of a vertical helical coil on a bubbly flow

NASA Astrophysics Data System (ADS)

Saffari, H.; Moosavi, R.

2014-11-01

In this article, turbulent single-phase and two-phase (air-water) bubbly fluid flows in a vertical helical coil are analyzed by using computational fluid dynamics (CFD). The effects of the pipe diameter, coil diameter, coil pitch, Reynolds number, and void fraction on the pressure loss, friction coefficient, and flow characteristics are investigated. The Eulerian-Eulerian model is used in this work to simulate the two-phase fluid flow. Three-dimensional governing equations of continuity, momentum, and energy are solved by using the finite volume method. The k- ɛ turbulence model is used to calculate turbulence fluctuations. The SIMPLE algorithm is employed to solve the velocity and pressure fields. Due to the effect of a secondary force in helical pipes, the friction coefficient is found to be higher in helical pipes than in straight pipes. The friction coefficient increases with an increase in the curvature, pipe diameter, and coil pitch and decreases with an increase in the coil diameter and void fraction. The close correlation between the numerical results obtained in this study and the numerical and empirical results of other researchers confirm the accuracy of the applied method. For void fractions up to 0.1, the numerical results indicate that the friction coefficient increases with increasing the pipe diameter and keeping the coil pitch and diameter constant and decreases with increasing the coil diameter. Finally, with an increase in the Reynolds number, the friction coefficient decreases, while the void fraction increases.

Medium term outcome of bipolar plasma vaporization in prostate cancer patients--a palliative modality of preserving spontaneous voiding.

PubMed

Geavlete, B; Moldoveanu, C; Niţă, Gh; Stănescu, F; Jecu, M; Geavlete, P

2012-12-15

This retrospective analysis evaluated the efficiency, safety, and medium term postoperative results of bipolar plasma vaporization (BPV) in prostate cancer (PCa) cases associating complete urinary retention. A series of 40 patients diagnosed with locally advanced or metastatic PCa and complete urinary retention requiring a Foley catheter indwelling underwent BPV aiming to restore spontaneous voiding. A total of 35 patients completed the one year evaluation protocol consisting of International Prostate Symptom Score (IPSS), quality of life score (QoL), maximum flow rate (Q(max)) and post-voiding residual urinary volume (PVR), measured at 1, 3, 6 and 12 months after surgery. BPV was successfully performed in all cases with satisfactory efficiency, as confirmed by the mean operation time (42.8 minutes) and hemoglobin drop (0.7 g/dl). A fast and safe postoperative recovery period was described in this series (hematuria rate--7.5%; mean catheterization period--36 hours; mean hospital stay--2.5 days; early-irritative symptoms' rate--15%). At 1, 3, 6 and 12 months, satisfactory values were determined in terms of IPSS, Qmax, QoL and PVR. These parameters emphasized a stable evolution throughout the entire follow-up, as 88.6% of the patients maintained spontaneous voiding. The present trial confirmed the plasma-button vaporization as a promising therapeutic approach in PCa cases associating complete urinary retention. The technique displayed good efficacy, low perioperative morbidity, short convalescence, and satisfactory urodynamics and symptom score parameters during the one-year follow-up period.

Theoretical study of the partial molar volume change associated with the pressure-induced structural transition of ubiquitin

PubMed Central

Imai, Takashi; Ohyama, Shusaku; Kovalenko, Andriy; Hirata, Fumio

2007-01-01

The partial molar volume (PMV) change associated with the pressure-induced structural transition of ubiquitin is analyzed by the three-dimensional reference interaction site model (3D-RISM) theory of molecular solvation. The theory predicts that the PMV decreases upon the structural transition, which is consistent with the experimental observation. The volume decomposition analysis demonstrates that the PMV reduction is primarily caused by the decrease in the volume of structural voids in the protein, which is partially canceled by the volume expansion due to the hydration effects. It is found from further analysis that the PMV reduction is ascribed substantially to the penetration of water molecules into a specific part of the protein. Based on the thermodynamic relation, this result implies that the water penetration causes the pressure-induced structural transition. It supports the water penetration model of pressure denaturation of proteins proposed earlier. PMID:17660257

Theoretical study of the partial molar volume change associated with the pressure-induced structural transition of ubiquitin.

PubMed

Imai, Takashi; Ohyama, Shusaku; Kovalenko, Andriy; Hirata, Fumio

2007-09-01

The partial molar volume (PMV) change associated with the pressure-induced structural transition of ubiquitin is analyzed by the three-dimensional reference interaction site model (3D-RISM) theory of molecular solvation. The theory predicts that the PMV decreases upon the structural transition, which is consistent with the experimental observation. The volume decomposition analysis demonstrates that the PMV reduction is primarily caused by the decrease in the volume of structural voids in the protein, which is partially canceled by the volume expansion due to the hydration effects. It is found from further analysis that the PMV reduction is ascribed substantially to the penetration of water molecules into a specific part of the protein. Based on the thermodynamic relation, this result implies that the water penetration causes the pressure-induced structural transition. It supports the water penetration model of pressure denaturation of proteins proposed earlier.

Prospective evaluation of the long-term effects of clinical voiding reeducation or voiding school for lower urinary tract conditions in children.

PubMed

Van den Broeck, C; de Mettelinge, T Roman; Deschepper, E; Van Laecke, E; Renson, C; Samijn, B; Hoebeke, P

2016-02-01

Although the short-term effects of urotherapy as a treatment strategy for lower urinary tract (LUT) conditions have been well documented, the long-term effects remain largely unknown. A better insight into the long-term effects of urotherapy could improve the clinical guidelines for children with incontinence. This study aimed to investigate the long-term effects (i.e., from 6 months to 2 years) from a clinical voiding reeducation program among children with LUT conditions. This study was a prospective continuation of the follow-up study of Hoebeke et al. (2011). Thirty-eight children (mean age 9 years) with LUT conditions completed an extensive clinical voiding reeducation program (VS). Data on medication, voiding, drinking, pelvic floor tone, uroflowmetry, and incontinence were recorded 2 years after the VS. These data were compared with the outcomes at 6 months follow-up and at intake before voiding school. Six months after voiding school, 22 children continued having daytime incontinence (ID) and/or enuresis (EN). Six of them became dry at 2 years. Conversely, 16 children were dry at 6 months, of which eight relapsed at 2 years. Whereas all parameters significantly improved 6 months after VS, further improvements from 6 months to 2 years could only be noticed for the proportion of children suffering from overactive bladder (92% at intake, 55% at 6-month follow-up and 18% at 2-year follow-up) (Figure). Fluid intake and pelvic floor tone improved after 6 months, but showed a significant relapse after 2 years (P = 0.013, P = 0.031, respectively). Hoebeke et al. (2011) concluded that results continued to improve after VS. No further improvements could be noticed 2 years after VS, although individual shifts were present. The results of the present study underline the value of long-term follow-up to detect those needing ongoing treatment to prevent relapse. Fluid intake and pelvic floor tone deteriorated from 6 months to 2 years. It could be hypothesized that inadequate fluid intake, possibly leading to decreased voided volumes, may be seen as an indicator for upcoming incontinence relapse. It could be stated that adequate fluid intake and pelvic floor tone may play a role in remaining continent for the long term. Study limitations should be considered. The study population was heterogeneous and rather small. Together with other missing values, this could have influenced the results. Close individual, long-term follow-up after clinical voiding reeducation in children is recommended in order to timely detect and prevent potential relapse. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Pathophysiological and Therapeutic Considerations for Non-Neurogenic Lower Urinary Tract Dysfunction in Children.

PubMed

Kakizaki, Hidehiro; Kita, Masafumi; Watanabe, Masaki; Wada, Naoki

2016-05-01

Non-neurogenic lower urinary tract dysfunction (LUTD) in children is very common in clinical practice and is important as an underlying cause of lower urinary tract symptoms, urinary tract infection and vesicoureteral reflux in affected children. LUTD in children is caused by multiple factors and might be related with a delay in functional maturation of the lower urinary tract. Behavioral and psychological problems often co-exist in children with LUTD and bowel dysfunction. Recent findings in functional brain imaging suggest that bladder bowel dysfunction and behavioral and psychiatric disorders in children might share common pathophysiological factors in the brain. Children with suspected LUTD should be evaluated properly by detailed history taking, validated questionnaire on voiding and defecation, voiding and bowel diary, urinalysis, screening ultrasound, uroflowmetry and post-void residual measurement. Invasive urodynamic study such as videourodynamics should be reserved for children in whom standard treatment fails. Initial treatment of non-neurogenic LUTD is standard urotherapy comprising education of the child and family, regular optimal voiding regimens and bowel programs. Pelvic floor muscle awareness, biofeedback and neuromodulation can be used as a supplementary purpose. Antimuscarinics and α-blockers are safely used for overactive bladder and dysfunctional voiding, respectively. For refractory cases, botulinum toxin A injection is a viable treatment option. Prudent use of urotherapy and pharmacotherapy for non-neurogenic LUTD should have a better chance to cure various problems and improve self-esteem and quality of life in affected children. © 2015 Wiley Publishing Asia Pty Ltd.

Multicenter, randomized, sham-controlled study on the efficacy of magnetic stimulation for women with urgency urinary incontinence.

PubMed

Yamanishi, Tomonori; Homma, Yukio; Nishizawa, Osamu; Yasuda, Kosaku; Yokoyama, Osamu

2014-04-01

To evaluate the efficacy and safety of magnetic stimulation for the treatment of urinary incontinence in women with overactive bladder. A total of 151 women with urgency incontinence were randomized to the active stimulation group or the sham stimulation group in a 2:1 order. An armchair type magnetic stimulator was used for 25-min magnetic stimulation twice a week, with the maximum magnetic flux density of 560 mT peak at 10 Hz. The sham device was set to deliver in a 5-s "on"-5-s "off" pulsing manner with the maximum intensity of 20.4% of active stimulation at 1 Hz. The study consisted of a baseline period for 1 week, and a treatment period for 6 weeks. The primary end-point was the number of leaks/week from the bladder diary. The secondary end-points were the number of voids and urgency/24 h, mean and maximum voided volume, and the quality of life assessment. Changes from baseline in the active and sham group, respectively, were -13.08 ± 11.00 and -8.68 ± 13.49 in leaks/week (P = 0.038), -2.65 ± 2.52 and -1.53 ± 2.39 in number of urgency/24 h (P = 0.011), and 14.03 ± 34.53 mL and -4.15 ± 40.60 mL in mean voided volume (P = 0.0056). As for safety, except for diarrhea and constipation, no patients experienced any device-related adverse event. Magnetic stimulation is effective for the treatment of urgency incontinence in female patients with overactive bladder. © 2013 The Japanese Urological Association.

Repeated variate stress in male rats induces increased voiding frequency, somatic sensitivity, and urinary bladder nerve growth factor expression

PubMed Central

Merrill, Liana; Malley, Susan

2013-01-01

Stress exacerbates symptoms of functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) in humans, but mechanisms contributing to symptom worsening are unknown. These studies address stress-induced changes in the structure and function of the micturition reflex using an animal model of stress in male rats. Rats were exposed to 7 days of repeated variate stress (RVS). Target organ (urinary bladder, thymus, adrenal gland) tissues were collected and weighed following RVS. Evans blue (EB) concentration and histamine, myeloperoxidase (MPO), nerve growth factor (NGF), brain-derived neurotropic factor (BDNF), and CXCL12 protein content (ELISA) were measured in the urinary bladder, and somatic sensitivity of the hindpaw and pelvic regions was determined following RVS. Bladder function was evaluated using continuous, open outlet intravesical infusion of saline in conscious rats. Increases in body weight gain were significantly (P ≤ 0.01) attenuated by day 5 of RVS, and adrenal weight was significantly (P ≤ 0.05) increased. Histamine, MPO, NGF, and CXCL12 protein expression was significantly (P ≤ 0.01) increased in the urinary bladder after RVS. Somatic sensitivity of the hindpaw and pelvic regions was significantly (P ≤ 0.01) increased at all monofilament forces tested (0.1–4 g) after RVS. Intercontraction interval, infused volume, and void volume were significantly (P ≤ 0.01) decreased after RVS. These studies demonstrate increased voiding frequency, histamine, MPO, NGF, and CXCL12 bladder content and somatic sensitivity after RVS suggesting an inflammatory component to stress-induced changes in bladder function and somatic sensitivity. PMID:23657640

Bladder outlet obstruction in women: definition and characteristics.

PubMed

Groutz, A; Blaivas, J G; Chaikin, D C

2000-01-01

The prevalence of bladder outlet obstruction in women is unknown and most probably has been underestimated. Moreover, there are no standard definitions for the diagnosis of bladder outlet obstruction in women. Our study was conducted to define as well as to examine the clinical and urodynamic characteristics of bladder outlet obstruction among women referred for evaluation of voiding symptoms. Bladder outlet obstruction was defined as a persistent, low, maximum "free" flow rate of <12 mL/s in repeated non-invasive uroflow studies, combined with high detrusor pressure at a maximum flow (p(det.Q)(max) >20 cm H(2)O) during detrusor pressure-uroflow studies. A urodynamic database of 587 consecutive women identified 38 (6.5%) women with bladder outlet obstruction. The mean age of the patients was 63.9 +/- 17.5 years. The mean maximum "free" flow, voided volume, and residual urinary volume were 9.4 +/-3.9 mL/s, 144. 9 +/- 72.7 mL, and 86.1 +/- 98.8 mL, respectively. The mean p(det. Q)(max) was 37.2 +/- 19.2 cm H(2)O. Previous anti-incontinence surgery and severe genital prolapse were the most common etiologies, accounting for half of the cases. Other, less common, etiologies included urethral stricture (13%), primary bladder neck obstruction (8%), learned voiding dysfunction (5%), and detrusor external sphincter dyssynergia (5%). Symptomatology was defined as mixed obstructive and irritative in 63% of the patients, isolated irritative in 29%, and isolated obstructive in other 8%. In conclusion, bladder outlet obstruction in women appears to be more common than was previously recognized, occurring in 6.5% of our patients. Micturition symptoms relevant to bladder outlet obstruction are non-specific, and a full urodynamic evaluation is essential in making the correct diagnosis and formulating a treatment plan.

Heat Transfar Properties of Flat-Panel Evacuated Porous Insrlators

NASA Astrophysics Data System (ADS)

Yoneno, Hirosyi; Yamamoto, Ryoichi

Flat Panel evacuated porous insulators have been produced by filling powder or fiber (such as perlite powder, diatomaceous earth powder, silica aerogel powder, g lass fiber and ceramic fiber) in film-like laminated plastic container and by evacuating to form vacuum in it is interior. Heat transfer properties of these evacuated insulators have been studied under various conditions (such as particle diameter, surface area, packing density, solid volume fraction and void dimension). The apparent mean thermal conductivity has been measured for the boundary surface temperature at cold face temperature 13°C and hot face temperature 35°. The effect of air pressure ranging from 1 Pa to one atomosphere (105 Pa) was examined. The results were as follows. (1) For each powder the apparent mean thermal conductivity decreases with decreasing residual air pressure, and at very low pressure bellow 1 -103 Pa the conductivity becomes indeqendent of pressure. The thermal conductivity at 1.3Pa is 0.0053 W/mK for perlite powder, 0.0048W/mK for diatomaceous earth powder, 0.0043 W/mK for silica aerogel powder and 0.0029W/mK for glass fiber. (2) With decreasing particle size, the apparent mean thermal conductivity is constant independent of residual air pressure in higher pressure region. It is that void dimension continues to decrease with particle size and the mean free path of air becomes comparable with void dimension. (3) In the range of minor solid volume fraction, the apparent mean thermal conductivity at very low precreases with decreasing particle size. This shows the thermal contact resistance of the solid particle increases with decreasing particle size.

Interaction of nanosecond ultraviolet laser pulses with reactive dusty plasma

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

Wetering, F. M. J. H. van de; Oosterbeek, W.; Beckers, J.

2016-05-23

Even though UV laser pulses that irradiate a gas discharge are small compared to the plasma volume (≲3%) and plasma-on time (≲6 × 10{sup −6}%), they are found to dramatically change the discharge characteristics on a global scale. The reactive argon–acetylene plasma allows the growth of nanoparticles with diameters up to 1 μm, which are formed inside the discharge volume due to spontaneous polymerization reactions. It is found that the laser pulses predominantly accelerate and enhance the coagulation phase and are able to suppress the formation of a dust void.

Modeling quiescent phase transport of air bubbles induced by breaking waves

NASA Astrophysics Data System (ADS)

Shi, Fengyan; Kirby, James T.; Ma, Gangfeng

Simultaneous modeling of both the acoustic phase and quiescent phase of breaking wave-induced air bubbles involves a large range of length scales from microns to meters and time scales from milliseconds to seconds, and thus is computational unaffordable in a surfzone-scale computational domain. In this study, we use an air bubble entrainment formula in a two-fluid model to predict air bubble evolution in the quiescent phase in a breaking wave event. The breaking wave-induced air bubble entrainment is formulated by connecting the shear production at the air-water interface and the bubble number intensity with a certain bubble size spectra observed in laboratory experiments. A two-fluid model is developed based on the partial differential equations of the gas-liquid mixture phase and the continuum bubble phase, which has multiple size bubble groups representing a polydisperse bubble population. An enhanced 2-DV VOF (Volume of Fluid) model with a k - ɛ turbulence closure is used to model the mixture phase. The bubble phase is governed by the advection-diffusion equations of the gas molar concentration and bubble intensity for groups of bubbles with different sizes. The model is used to simulate air bubble plumes measured in laboratory experiments. Numerical results indicate that, with an appropriate parameter in the air entrainment formula, the model is able to predict the main features of bubbly flows as evidenced by reasonable agreement with measured void fraction. Bubbles larger than an intermediate radius of O(1 mm) make a major contribution to void fraction in the near-crest region. Smaller bubbles tend to penetrate deeper and stay longer in the water column, resulting in significant contribution to the cross-sectional area of the bubble cloud. An underprediction of void fraction is found at the beginning of wave breaking when large air pockets take place. The core region of high void fraction predicted by the model is dislocated due to use of the shear production in the algorithm for initial bubble entrainment. The study demonstrates a potential use of an entrainment formula in simulations of air bubble population in a surfzone-scale domain. It also reveals some difficulties in use of the two-fluid model for predicting large air pockets induced by wave breaking, and suggests that it may be necessary to use a gas-liquid two-phase model as the basic model framework for the mixture phase and to develop an algorithm to allow for transfer of discrete air pockets to the continuum bubble phase. A more theoretically justifiable air entrainment formulation should be developed.

Modeling multiscale evolution of numerous voids in shocked brittle material.

PubMed

Yu, Yin; Wang, Wenqiang; He, Hongliang; Lu, Tiecheng

2014-04-01

The influence of the evolution of numerous voids on macroscopic properties of materials is a multiscale problem that challenges computational research. A shock-wave compression model for brittle material, which can obtain both microscopic evolution and macroscopic shock properties, was developed using discrete element methods (lattice model). Using a model interaction-parameter-mapping procedure, qualitative features, as well as trends in the calculated shock-wave profiles, are shown to agree with experimental results. The shock wave splits into an elastic wave and a deformation wave in porous brittle materials, indicating significant shock plasticity. Void collapses in the deformation wave were the natural reason for volume shrinkage and deformation. However, media slippage and rotation deformations indicated by complex vortex patterns composed of relative velocity vectors were also confirmed as an important source of shock plasticity. With increasing pressure, the contribution from slippage deformation to the final plastic strain increased. Porosity was found to determine the amplitude of the elastic wave; porosity and shock stress together determine propagation speed of the deformation wave, as well as stress and strain on the final equilibrium state. Thus, shock behaviors of porous brittle material can be systematically designed for specific applications.

Quantitative controls on submarine slope failure morphology

USGS Publications Warehouse

Lee, H.J.; Schwab, W.C.; Edwards, B.D.; Kayen, R.E.

1991-01-01

The concept of the steady-state of deformation can be applied to predicting the ultimate form a landslide will take. The steady-state condition, defined by a line in void ratio-effective stress space, exists at large levels of strain and remolding. Conceptually, if sediment initially exists with void ratio-effective stress conditions above the steady-state line, the sediment shear strength will decrease during a transient loading event, such as an earthquake or storm. If the reduced shear strength existing at the steady state is less than the downslope shear stress induced by gravity, then large-scale internal deformation, disintegration, and flow will occur. -from Authors

Origami: Delineating Cosmic Structures with Phase-Space Folds

NASA Astrophysics Data System (ADS)

Neyrinck, Mark C.; Falck, Bridget L.; Szalay, Alex S.

2015-01-01

Structures like galaxies and filaments of galaxies in the Universe come about from the origami-like folding of an initially flat three-dimensional manifold in 6D phase space. The ORIGAMI method identifies these structures in a cosmological simulation, delineating the structures according to their outer folds. Structure identification is a crucial step in comparing cosmological simulations to observed maps of the Universe. The ORIGAMI definition is objective, dynamical and geometric: filament, wall and void particles are classified according to the number of orthogonal axes along which dark-matter streams have crossed. Here, we briefly review these ideas, and speculate on how ORIGAMI might be useful to find cosmic voids.

Some TEM observations of Al2O3 scales formed on NiCrAl alloys

NASA Technical Reports Server (NTRS)

Smialek, J.; Gibala, R.

1979-01-01

The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids were observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. The voids resulted from an excess number of oxygen vacancies near the oxidemetal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidation of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al, Cr)2O3 and Ni(Al, Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationship between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

Atomistic Simulation of Initiation in Hexanitrostilbene

NASA Astrophysics Data System (ADS)

Shan, Tzu-Ray; Wixom, Ryan; Yarrington, Cole; Thompson, Aidan

2015-06-01

We report on the effect of cylindrical voids on hot spot formation, growth and chemical reaction initiation in hexanitrostilbene (HNS) crystals subjected to shock. Large-scale, reactive molecular dynamics simulations are performed using the reactive force field (ReaxFF) as implemented in the LAMMPS software. The ReaxFF force field description for HNS has been validated previously by comparing the isothermal equation of state to available diamond anvil cell (DAC) measurements and density function theory (DFT) calculations and by comparing the primary dissociation pathway to ab initio calculations. Micron-scale molecular dynamics simulations of a supported shockwave propagating through the HNS crystal along the [010] orientation are performed with an impact velocity (or particle velocity) of 1.25 km/s, resulting in shockwave propagation at 4.0 km/s in the bulk material and a bulk shock pressure of ~ 11GPa. The effect of cylindrical void sizes varying from 0.02 to 0.1 μm on hot spot formation and growth rate has been studied. Interaction between multiple voids in the HNS crystal and its effect on hot spot formation will also be addressed. Results from the micron-scale atomistic simulations are compared with hydrodynamics simulations. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Granular mechanics of normally consolidated fine soils

NASA Astrophysics Data System (ADS)

Yanqui, Calixtro

2017-06-01

In this paper, duality is demonstrated to be one of the inherent properties of granular packings, by mapping the stress-strain curve into the diagram that relates the pore ratio and the localization of the contact point. In this way, it is demonstrated that critical state is not related to the maximum void ratio, but to a unique value related to two different angles of packing, one limiting the domain of the dense state, and other limiting the domain of the loose state. As a consequence, packings can be dilative or contractive, as mutually exclusive states, except by the critical state point, where equations for both granular packings are equally valid. Further analysis shows that stresses, in a dilative packing, are transmitted by chains of contact forces, and, in a contractive packing, by shear forces. So that, stresses, for the first case, depend on the initial void ratio, and, for the second case, are independent. As it is known, normally consolidated and lightly overconsolidated fine soils are in loose state, and, hence, their strength is constant, because it does not depend on their initial void ratio; except at the critical state, for which, the consolidated-drained angle of friction is related to the plasticity index or the liquid limit. In this fashion, experimental results reported by several authors around the world are confronted with the theory, showing a good agreement.

Collected Works of Mao Tse-Tung (1917-1949), Volume 3

DTIC Science & Technology

1978-10-05

factories) are to be nationalized. Lend- lease contracts will be re- negotiated on some foreign business enterprises currently being allowed to operate...holds that all negotiations and agreements between them and imperialism are null and void. With regard to the Manchuria incident, we 39 propose the...all negotiations and secret treaties between the Kuomintang and imperialism! Overthrow the counterrevolutionary rule of the Kuomintang! Down with

Basic Course Deskbook, Volume 2: General Administrative Law

DTIC Science & Technology

2002-03-01

jurisdictions can result in a void marriage. 5. Impotence: usually must render the party physically incapable of normal sexual relations and must...ground for annulment in itself, but may constitute fraud if the party never intended to have sexual relations. IX. UNIFORMED SERVICES FORMER SPOUSES...must submit a sworn statement articulating reasonable facts supporting the existence or nonexistence of requisite sexual contact before genetic

Thermoelectric module

DOEpatents

Kortier, William E.; Mueller, John J.; Eggers, Philip E.

1980-07-08

A thermoelectric module containing lead telluride as the thermoelectric mrial is encapsulated as tightly as possible in a stainless steel canister to provide minimum void volume in the canister. The lead telluride thermoelectric elements are pressure-contacted to a tungsten hot strap and metallurgically bonded at the cold junction to iron shoes with a barrier layer of tin telluride between the iron shoe and the p-type lead telluride element.

Biostimulation and rainfall infiltration: influence on retention of biodiesel in residual clayey soil.

PubMed

Thomé, Antônio; Cecchin, Iziquiel; Reginatto, Cleomar; Colla, Luciane M; Reddy, Krishna R

2017-04-01

This study investigates the retention of biodiesel in residual clayey soil during biostimulation by nutrients (nitrogen, phosphorus, and potassium) under conditions of rainfall infiltration. Several column tests were conducted in a laboratory under different void ratios (1.14, 1.24, and 1.34), varying moisture contents (15, 25, and 35%), and in both the presence and absence of biostimulation. The volume of biodiesel (which was equivalent to the volume of voids in the soil) was placed atop the soil and allowed to percolate for a period of 15 days. The soil was subjected to different rainfall infiltration conditions (0.30 or 60 mm). The greatest reductions in residual contaminants occurred after 60 mm of rain simulation, at values of up to 74% less than in samples with the same conditions but no precipitation. However, the residual contamination decay rate was greater with 0-30 mm (0.29 g/mm) of precipitation than with 30-60 mm (0.075 g/mm). Statistical assessment revealed that increased moisture and the presence of nutrients were the factors with the most powerful effect on contaminant retention in the soil. The residual contaminant level was 21 g/kg at a moisture content of 15% and no precipitation, decreasing to 12 g/kg at 35% moisture and no precipitation. Accordingly, it is possible to conclude that biostimulation and rainfall infiltration conditions can decrease the retention of contaminants in soil and allow a greater leaching or spreading of the contamination. All of these phenomena are worthy of careful examination for the in situ bioremediation of organic contamination. • The higher moisture in the soil, due to a high initial moisture content and/or infiltration of rainfall, can reduce contaminant retention, • The use of biostimulation through the addition of nutrients to accelerate the biodegradation of toxic organic contaminants may induce inadvertent undesirable interactions between the soil and the contaminant. • When adopting biostimulation for bioremediation, the effects of rainfall should be addressed; ideally, it should be prevented from entering the affected site, in order to avoid increased contaminant leaching and potential spreading.

Abobotulinum - a toxin injection in patients with refractory idiopathic detrusor overactivity: injections in detrusor, trigone and bladder neck or prostatic urethra, versus detrusor - only injections

PubMed Central

Emami, Maryam; Shadpour, Pejman; Kashi, Amir H.; Choopani, Masoud; Zeighami, Mohammadreza

2017-01-01

ABSTRACT Purpose: To evaluate if the injections of abobotulinum-A toxin in trigone and bladder neck/prostatic urethra in addition to detrusor provides better symptoms relief and urodynamic findings in patients with idiopathic detrusor overactivity (IDO) refractory to medical treatment. Materials and Methods: A total of 74 patients with IDO refractory to anticholinergics received injections in detrusor, trigone and bladder neck/prostatic urethra (Group A, N=36) versus detrusor only injections (Group B, N=38) of abobotulinum-A toxin. All patients were evaluated by a standard overactive bladder symptom score (OABSS) questionnaire and cystometrography before and 6 weeks after the operation. OABSS questionnaire was also completed 20 weeks after the operation. Results: The magnitude of OABSS reduction from baseline to 6 weeks after operation in groups A and B patients was 13.4±2.2 versus 11.7±2.1 (p=0.001). Cystometry results were similar in both groups except for higher volume at urgent desire to void in Group B patients (p <0.001). The mean±SD change in residual volume in Group A at 6 weeks after the operation was −4.8±28.6mL (p=0.33) compared to 21.3±16.9mL in Group B patients (p <0.001). Conclusions: In patients with IDO, adding trigone, and bladder neck/prostatic urethra as sites of abobotulinum- A toxin injection produces greater reductions in OABSS score and less residual urine volume but a lower volume at urgent desire to void in comparison with detrusor only injections. PMID:28727385

Topology Analysis of the Sloan Digital Sky Survey. I. Scale and Luminosity Dependence

NASA Astrophysics Data System (ADS)

Park, Changbom; Choi, Yun-Young; Vogeley, Michael S.; Gott, J. Richard, III; Kim, Juhan; Hikage, Chiaki; Matsubara, Takahiko; Park, Myeong-Gu; Suto, Yasushi; Weinberg, David H.; SDSS Collaboration

2005-11-01

We measure the topology of volume-limited galaxy samples selected from a parent sample of 314,050 galaxies in the Sloan Digital Sky Survey (SDSS), which is now complete enough to describe the fully three-dimensional topology and its dependence on galaxy properties. We compare the observed genus statistic G(νf) to predictions for a Gaussian random field and to the genus measured for mock surveys constructed from new large-volume simulations of the ΛCDM cosmology. In this analysis we carefully examine the dependence of the observed genus statistic on the Gaussian smoothing scale RG from 3.5 to 11 h-1 Mpc and on the luminosity of galaxies over the range -22.50

Subsidence and collapse sinkholes in soluble rock: a numerical perspective

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Romanov, Douchko; Hiller, Thomas

2016-04-01

Soluble rocks such as limestone, gypsum, anhydrite, and salt are prone to subsidence and the sudden creation of collapse sinkholes. The reason for this behaviour stems from the solubility of the rock: Water percolating through fissures and bedding partings can remove material from the rock walls and thus increase the permeability of the host rock by orders of magnitudes. This process occurs on time scales of 1,000-100,000 years, resulting in enlarged fractures, voids and cavities, which then carry flow efficiently through the rock. The enlargement of sub-surface voids to the meter-size within such short times creates mechanical conditions prone to collapse. The collapse initiates at depth, but then propagates to the surface. By means of numerical modelling, we discuss the long-term evolution of secondary porosity in gypsum rocks, resulting in zones of sub-surface voids, which then become mechanically unstable and collapse. We study two real-world case scenarios, in which we can relate field observations to our numerical model: (i) A dam-site scenario, where flow around the dam caused widespread dissolution of gypsum and subsequent subsidence of the dam and a nearby highway. (ii) A natural collapse sinkhole forming as a result of freshwater inflow into a shallow anhydrite formation with rapid evolution of voids in the sub-surface.

Transcutaneous sacral neurostimulation for irritative voiding dysfunction.

PubMed

Walsh, I K; Johnston, R S; Keane, P F

1999-01-01

Patients with irritative voiding dysfunction are often unresponsive to standard clinical treatment. We evaluated the response of such individuals to transcutaneous electrical stimulation of the third sacral nerve. 32 patients with refractory irritative voiding dysfunction (31 female and 1 male; mean age 47 years) were recruited to the study. Ambulatory transcutaneous electrical neurostimulation was applied bilaterally to the third sacral dermatomes for 1 week. Symptoms of frequency, nocturia, urgency, and bladder pain were scored by each patient throughout and up to 6 months following treatment. The mean daytime frequency was reduced from 11.3 to 7.96 (p = 0.01). Nocturia episodes were reduced from a mean of 2.6 to 1.8 (p = 0.01). Urgency and bladder pain mean symptom scores were reduced from 5.97 to 4.89 and from 1.48 to 0.64, respectively. After stopping therapy, symptoms returned to pretreatment levels within 2 weeks in 40% of the patients and within 6 months in 100%. Three patients who continued with neurostimulation remained satisfied with this treatment modality at 6 months. Transcutaneous third sacral nerve stimulation may be an effective and noninvasive ambulatory technique for the treatment of patients with refractory irritative voiding dysfunction. Following an initial response, patients may successfully apply this treatment themselves to ensure long-term relief.

In Situ Observation of Modulated Light Emission of Fiber Fuse Synchronized with Void Train over Hetero-Core Splice Point

PubMed Central

Todoroki, Shin-ichi

2008-01-01

Background Fiber fuse is a process of optical fiber destruction under the action of laser radiation, found 20 years ago. Once initiated, opical discharge runs along the fiber core region to the light source and leaves periodic voids whose shape looks like a bullet pointing the direction of laser beam. The relation between damage pattern and propagation mode of optical discharge is still unclear even after the first in situ observation three years ago. Methodology/Principal Findings Fiber fuse propagation over hetero-core splice point (Corning SMF-28e and HI 1060) was observed in situ. Sequential photographs obtained at intervals of 2.78 µs recorded a periodic emission at the tail of an optical discharge pumped by 1070 nm and 9 W light. The signal stopped when the discharge ran over the splice point. The corresponding damage pattern left in the fiber core region included a segment free of periodicity. Conclusions The spatial modulation pattern of the light emission agreed with the void train formed over the hetero-core splice point. Some segments included a bullet-shaped void pointing in the opposite direction to the laser beam propagation although the sequential photographs did not reveal any directional change in the optical discharge propagation. PMID:18815621

Evaluation of pavement permeability in Mississippi.

DOT National Transportation Integrated Search

2003-07-01

The proper compaction of hot mix asphalt (HMA) pavements is vital for a stable and durable pavement. For dense-graded mixtures, it has been recommended that the initial in-place air voids at the time of construction should not be below 3 percent or a...

Simulation, imaging, and mechanics of asphalt pavement (SIMAP) initiative

DOT National Transportation Integrated Search

1998-07-01

Asphalt concrete is a complex material that consists of aggregates, asphalt, and air voids. Aggregates are held together by asphalt and form a skeleton to support the weight of vehicles. The stiffer the asphalt, the tighter the aggregates are held to...

The sparkling Universe: clustering of voids and void clumps

NASA Astrophysics Data System (ADS)

Lares, Marcelo; Ruiz, Andrés N.; Luparello, Heliana E.; Ceccarelli, Laura; Garcia Lambas, Diego; Paz, Dante J.

2017-07-01

We analyse the clustering of cosmic voids using a numerical simulation and the main galaxy sample from the Sloan Digital Sky Survey. We take into account the classification of voids into two types that resemble different evolutionary modes: those with a rising integrated density profile (void-in-void mode or R-type) and voids with shells (void-in-cloud mode or S-type). The results show that voids of the same type have stronger clustering than the full sample. We use the correlation analysis to define void clumps, associations with at least two voids separated by a distance of at most the mean void separation. In order to study the spatial configuration of void clumps, we compute the minimal spanning tree and analyse their multiplicity, maximum length and elongation parameter. We further study the dynamics of the smaller sphere that enclose all the voids in each clump. Although the global densities of void clumps are different according to their member-void types, the bulk motions of these spheres are remarkably lower than those of randomly placed spheres with the same radius distribution. In addition, the coherence of pairwise void motions does not strongly depend on whether voids belong to the same clump. Void clumps are useful to analyse the large-scale flows around voids, since voids embedded in large underdense regions are mostly in the void-in-void regime, where the expansion of the larger region produces the separation of voids. Similarly, voids around overdense regions form clumps that are in collapse, as reflected in the relative velocities of voids that are mostly approaching.

Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

NASA Astrophysics Data System (ADS)

Wiens, Roger C.; Rubin, David M.; Goetz, Walter; Fairén, Alberto G.; Schwenzer, Susanne P.; Johnson, Jeffrey R.; Milliken, Ralph; Clark, Ben; Mangold, Nicolas; Stack, Kathryn M.; Oehler, Dorothy; Rowland, Scott; Chan, Marjorie; Vaniman, David; Maurice, Sylvestre; Gasnault, Olivier; Rapin, William; Schroeder, Susanne; Clegg, Sam; Forni, Olivier; Blaney, Diana; Cousin, Agnes; Payré, Valerie; Fabre, Cecile; Nachon, Marion; Le Mouelic, Stephane; Sautter, Violaine; Johnstone, Stephen; Calef, Fred; Vasavada, Ashwin R.; Grotzinger, John P.

2017-06-01

Voids and hollow spheroids between ∼1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302-305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1-4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only one hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. Origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Although some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions.

The use of XFEM to assess the influence of intra-cortical porosity on crack propagation.

PubMed

Rodriguez-Florez, Naiara; Carriero, Alessandra; Shefelbine, Sandra J

2017-03-01

This study aimed at using eXtended finite element method (XFEM) to characterize crack growth through bone's intra-cortical pores. Two techniques were compared using Abaqus: (1) void material properties were assigned to pores; (2) multiple enrichment regions with independent crack-growth possibilities were employed. Both were applied to 2D models of transverse images of mouse bone with differing porous structures. Results revealed that assigning multiple enrichment regions allows for multiple cracks to be initiated progressively, which cannot be captured when the voids are filled. Therefore, filling pores with one enrichment region in the model will not create realistic fracture patterns in Abaqus-XFEM.

Partial bladder outlet obstruction induces urethral smooth muscle hypertrophy and decreased force generation.

PubMed

Hypolite, Joseph A; Chang, Shaohua; Zheng, Yongmu; DiSanto, Michael E; Zderic, Stephen A; Wein, Alan J; Chacko, Samuel

2006-02-01

PBOO leads to increased urinary frequency, decreased void volume, hypertrophy of the detrusor SM, and alterations in contractile and regulatory proteins. This study was done to determine whether PBOO induced increases in urinary frequency and detrusor SM hypertrophy are associated with an alteration in the contractility and expression of myosin isoforms in urethral SM. PBOO was surgically induced in male New Zealand White rabbits, and sham operated rabbits served as controls. After surgery, rabbits were kept 12 days, and prior to sacrifice, urine output and voiding frequency were monitored by keeping the animals in metabolic cages for 24 hours. Animals with increased urinary frequency (mean +/- SEM 43 +/- 12 voids per 24 hours) and sham operated rabbits (6 +/- 3 voids per 24 hours) were used for this study. Morphology of the urethra was studied using light and immunofluorescence microscopy. The expression of myosin isoforms was analyzed at the mRNA and protein levels by RT-PCR and Western blotting. The urethral wall and SM of PBOO rabbits showed hypertrophy. The force produced by the longitudinal muscle strips of PBOO animals in response to phenylephrine, KCl, or electrical field stimulation was decreased 50%, 37% and 40%, respectively. Immunofluorescence microscopy revealed a decrease in nerve density. RT-PCR and Western blotting showed a decrease in the expression of myosin isoform SM-B with a concomitant increase in SM-A at the mRNA and protein levels. Our data show hypertrophy of the urethral wall and SM, and alterations in contraction, innervation, and myosin isoforms in PBOO induced detrusor hypertrophy.

Percutaneous nerve evaluation (PNE) for treatment of non-obstructive urinary retention: urodynamic changes, placebo effects, and response rates.

PubMed

Sharifiaghdas, Farzaneh; Mirzaei, Mahboubeh; Ahadi, Babak

2014-03-04

To evaluate the results of percutaneous nerve evaluation (PNE) implantation in the treatment of non-obstructive urinary retention and report the changes in the urodynamic parameters. Patients with non-obstructive urinary retention or incomplete bladder emptying were included. All patients filled a 7 days voiding diary chart and underwent PNE for one week, and the patient was asked to record the second voiding diary chart and repeat urodynamic study in this period. Then the PNE lead was removed from the S3 foramen, but the connections remained fixed in place for another 3 days to exclude the placebo effects and the third voiding diary chart was completed by the patient. The patient wasn't aware of lead removal. Success was defined as, more than 50% improvement in at least one of the urinary tract symptoms. Forty five patients with a mean age of 37.1 years (ranged 9-83 years) were treated with PNE for refractory, non-obstructive urinary retention. Of study subjects 28 complained from complete urinary retention, and 17 had incomplete emptying. Of participants, 28 (62.2%) demonstrated greater than 50% improvement in the urinary symptoms. Urodynamic data, showed a statistically significant increase in maximum flow rate (8 ± 2.2 mL/sec to 16 ± 3.6 mL/sec, P = .06) and voided volume (35 mL to 187 mL, P = .032) in the responders. Any placebo effects in PNE have not been seen. Patients with complete non obstructive urinary retention were good responders to PNE. The placebo effect in sacral nerve stimulation was negligible.

Sacral neuromodulation for the treatment of neurogenic lower urinary tract dysfunction caused by multiple sclerosis: a single-centre prospective series.

PubMed

Engeler, Daniel S; Meyer, Daniel; Abt, Dominik; Müller, Stefanie; Schmid, Hans-Peter

2015-10-23

Sacral neuromodulation is well established in the treatment of refractory, non-neurogenic lower urinary tract dysfunction, but its efficacy and safety in patients with lower urinary tract dysfunction of neurological origin is unclear. Only few case series have been reported for multiple sclerosis. We prospectively evaluated the efficacy and safety of sacral neuromodulation in patients with multiple sclerosis. Seventeen patients (13 women, 4 men) treated with sacral neuromodulation for refractory neurogenic lower urinary tract dysfunction caused by multiple sclerosis were prospectively enrolled (2007-2011). Patients had to have stable disease and confirmed neurogenic lower urinary tract dysfunction. Voiding variables, adverse events, and subjective satisfaction were assessed. Sixteen (94 %) patients had a positive test phase with a >70 % improvement. After implantation of the pulse generator (InterStim II), the improvement in voiding variables persisted. At 3 years, the median voided volume had improved significantly from 125 (range 0 to 350) to 265 ml (range 200 to 350) (p < 0.001), the post void residual from 170 (range 0 to 730) to 25 ml (range 0 to 300) (p = 0.01), micturition frequency from 12 (range 6 to 20) to 7 (range 4 to 12) (p = 0.003), and number of incontinence episodes from 3 (range 0 to 10) to 0 (range 0 to 1) (p = 0.006). The median subjective degree of satisfaction was 80 %. Only two patients developed lack of benefit. No major complications occurred. Chronic sacral neuromodulation promises to be an effective and safe treatment of refractory neurogenic lower urinary tract dysfunction in selected patients with multiple sclerosis.

A dynamical classification of the cosmic web

NASA Astrophysics Data System (ADS)

Forero-Romero, J. E.; Hoffman, Y.; Gottlöber, S.; Klypin, A.; Yepes, G.

2009-07-01

In this paper, we propose a new dynamical classification of the cosmic web. Each point in space is classified in one of four possible web types: voids, sheets, filaments and knots. The classification is based on the evaluation of the deformation tensor (i.e. the Hessian of the gravitational potential) on a grid. The classification is based on counting the number of eigenvalues above a certain threshold, λth, at each grid point, where the case of zero, one, two or three such eigenvalues corresponds to void, sheet, filament or a knot grid point. The collection of neighbouring grid points, friends of friends, of the same web type constitutes voids, sheets, filaments and knots as extended web objects. A simple dynamical consideration of the emergence of the web suggests that the threshold should not be null, as in previous implementations of the algorithm. A detailed dynamical analysis would have found different threshold values for the collapse of sheets, filaments and knots. Short of such an analysis a phenomenological approach has been opted for, looking for a single threshold to be determined by analysing numerical simulations. Our cosmic web classification has been applied and tested against a suite of large (dark matter only) cosmological N-body simulations. In particular, the dependence of the volume and mass filling fractions on λth and on the resolution has been calculated for the four web types. We also study the percolation properties of voids and filaments. Our main findings are as follows. (i) Already at λth = 0.1 the resulting web classification reproduces the visual impression of the cosmic web. (ii) Between 0.2 <~ λth <~ 0.4, a system of percolated voids coexists with a net of interconnected filaments. This suggests a reasonable choice for λth as the parameter that defines the cosmic web. (iii) The dynamical nature of the suggested classification provides a robust framework for incorporating environmental information into galaxy formation models, and in particular to semi-analytical models.

Experimental Investigation of Relative Permeability Upscaling from the Micro-Scale to the Macro-Scale

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

Pyrak-Nolte, Laura J.; Cheng, JiangTao; Yu, Ping

2003-01-29

During this reporting period, shown experimentally that the optical coherence imaging system can acquire information on grain interfaces and void shape for a maximum depth of half a millimeter into sandstone. The measurement of interfacial area per volume (IAV), capillary pressure and saturation in two dimensional micro-models structures has shown the existence of a unique relationship among these hydraulic parameters for different pore geometry. The measurement of interfacial area per volume on a three-dimensional natural sample, i.e., sandstone, has shown the homogeneity of IAV with depth in a sample when the fluids are in equilibrium.

All-in-one assembly based on 3D-intertangled and cross-jointed architectures of Si/Cu 1D-nanowires for lithium ion batteries

PubMed Central

Hwang, Chihyun; Kim, Tae-Hee; Cho, Yoon-Gyo; Kim, Jieun; Song, Hyun-Kon

2015-01-01

All-in-one assemblies of separator, electrode and current collector (SECA) for lithium ion batteries are presented by using 1D nanowires of Si and Cu (nwSi and nwCu). Even without binders, integrity of SECA is secured via structural joints based on ductility of Cu as well as entanglement of nwSi and nwCu. By controlling the ratio of the nanowires, the number of contact points and voids accommodating volume expansion of Si active material are tunable. Zero volume expansion and high energy density are simultaneously achievable by the architecture. PMID:25720334

Development of nano-fabrication technique utilizing self-organizational behavior of point defects induced by ion irradiation

NASA Astrophysics Data System (ADS)

Nitta, Noriko; Taniwaki, Masafumi

2006-04-01

The present authors proposed a novel nano-fabrication technique that is able to arrange the fine cells orderly, based on their finding in GaSb implanted at a low temperature. In this article, first the experimental results that anomalous cellular structure was formed in GaSb by ion implantation is introduced and the self-organizational formation mechanism of the structure is described. Next a nano-fabrication technique that utilizes focused ion beam is described. This technique consists of two procedures, i.e. the formation process of the voids array and the development of the initial array to ordered cellular structure. Finally, the nano-fabrication is actually performed by this technique and their results are reported. Fabrication succeeded in structures where the dot (cell) interval was 100 nm or larger. The minimum ion dose for initial voids which develops to the ordered cellular structure is evaluated. It is also shown that the substrate temperature during implantation is an essential parameter for this technique.

A study of the formation and dynamics of galaxies

NASA Astrophysics Data System (ADS)

Fillmore, J. A.

The first half of this thesis is a study on the growth of perturbations in the early universe which might lead to galaxies, clusters of galaxies, or regions void of galaxies. The growth of self-similar perturbations in an Einstein-deSitter universe with cold, collisionless particles is investigated. Three classes of solutions are obtained; one each with planar, cylindrical, and spherical symmetry. The solutions follow the development of structure in both the linear and nonlinear regimes. Self-similar spherical voids which develop from initially underdense regions are also investigated. The character of each solution depends upon the initial density deficit. The second half of this thesis details solutions of steady-state axisymmetric models of elliptical and disk galaxies, and considers which observable properties can be used as diagnostics of the kinematic configuration of the spheroidal component of these systems. Two component mass models are fitted to surface brightness measurements and used to fit kinematic models to the velocity data.

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2018-06-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

NASA Astrophysics Data System (ADS)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2017-12-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Terahertz Computed Tomography of NASA Thermal Protection System Materials

NASA Technical Reports Server (NTRS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Molded underfill (MUF) encapsulation for flip-chip package: A numerical investigation

NASA Astrophysics Data System (ADS)

Azmi, M. A.; Abdullah, M. K.; Abdullah, M. Z.; Ariff, Z. M.; Saad, Abdullah Aziz; Hamid, M. F.; Ismail, M. A.

2017-07-01

This paper presents the numerical simulation of epoxy molding compound (EMC) filling in multi flip-chip packages during encapsulation process. The empty and a group flip chip packages were considered in the mold cavity in order to study the flow profile of the EMC. SOLIDWORKS software was used for three-dimensional modeling and it was incorporated into fluid analysis software namely as ANSYS FLUENT. The volume of fluid (VOF) technique was used for capturing the flow front profiles and Power Law model was applied for its rheology model. The numerical result are compared and discussed with previous experimental and it was shown a good conformity for model validation. The prediction of flow front was observed and analyzed at different filling time. The possibility and visual of void formation in the package is captured and the number of flip-chip is one factor that contributed to the void formation.

The Shock and Vibration Digest. Volume 18, Number 1

DTIC Science & Technology

1986-01-01

polyurethanes reduced the loss factor and emphasized the correlation between molecular storage modulus by increasing the length of the structure and...one tempera- static deformations. He gave storage and loss ture/frequency range is difficult with copoly- moduli for a carbon black filled and an...has been described (18). The shear loss author states that the frequency dependence of and storage moduli of a void-filled polyurethane the elastomers

Gamma knife surgery for brainstem arteriovenous malformations.

PubMed

Yen, Chun-Po; Steiner, Ladislau

2011-01-01

To evaluate the long-term imaging and clinical outcomes of patients with brainstem arteriovenous malformations (AVMs) treated with Gamma Knife surgery (GKS). The study included 85 patients with brainstem AVMs undergoing GKS during the period 1989-2007. The locations of the nidi were the midbrain in 42 patients, pons in 31 patients, and medulla oblongata in 12 patients. The volume of the nidi ranged from 0.1-8.9 mL (median 1.4 mL, mean 1.9 mL), and the prescription dose ranged from 5-32 Gy (median 20 Gy, mean 19.9 Gy). After the initial Gamma procedure, 18 patients had repeat GKS for AVM residuals that were still patent. Two patients had a third GKS 7 years and 16 years after a failed repeat GKS. Clinical follow-up ranged from 24-252 months with a mean of 100 months (median 102 months) after the initial GKS. GKS yielded a total angiographic obliteration in 50 (58.8%) patients and subtotal obliteration in 4 (4.7%) patients. In 22 (25.9%) patients, the AVMs remained patent. In 9 patients (10.6%), no flow voids were observed on magnetic resonance imaging (MRI), but angiographic confirmation was unavailable. A small nidus volume and a high prescription dose were significantly associated with increased AVM obliteration rate. Radiation-induced changes developed in 34 patients (40%); 24 were asymptomatic, 1 patient had only headache, and 9 patients developed neurologic deficits. One patient developed a large cyst 6 years after GKS. Given the poor surgical outcome of brainstem AVMs, the results of 59% nidus obliteration and 6% permanent neurologic deficits make GKS a reasonable management of these difficult lesions. Copyright © 2011 Elsevier Inc. All rights reserved.

Coupling curvature-dependent and shear stress-stimulated neotissue growth in dynamic bioreactor cultures: a 3D computational model of a complete scaffold.

PubMed

Guyot, Y; Papantoniou, I; Luyten, F P; Geris, L

2016-02-01

The main challenge in tissue engineering consists in understanding and controlling the growth process of in vitro cultured neotissues toward obtaining functional tissues. Computational models can provide crucial information on appropriate bioreactor and scaffold design but also on the bioprocess environment and culture conditions. In this study, the development of a 3D model using the level set method to capture the growth of a microporous neotissue domain in a dynamic culture environment (perfusion bioreactor) was pursued. In our model, neotissue growth velocity was influenced by scaffold geometry as well as by flow- induced shear stresses. The neotissue was modeled as a homogenous porous medium with a given permeability, and the Brinkman equation was used to calculate the flow profile in both neotissue and void space. Neotissue growth was modeled until the scaffold void volume was filled, thus capturing already established experimental observations, in particular the differences between scaffold filling under different flow regimes. This tool is envisaged as a scaffold shape and bioprocess optimization tool with predictive capacities. It will allow controlling fluid flow during long-term culture, whereby neotissue growth alters flow patterns, in order to provide shear stress profiles and magnitudes across the whole scaffold volume influencing, in turn, the neotissue growth.

Multibillion-atom Molecular Dynamics Simulations of Plasticity, Spall, and Ejecta

NASA Astrophysics Data System (ADS)

Germann, Timothy C.

2007-06-01

Modern supercomputing platforms, such as the IBM BlueGene/L at Lawrence Livermore National Laboratory and the Roadrunner hybrid supercomputer being built at Los Alamos National Laboratory, are enabling large-scale classical molecular dynamics simulations of phenomena that were unthinkable just a few years ago. Using either the embedded atom method (EAM) description of simple (close-packed) metals, or modified EAM (MEAM) models of more complex solids and alloys with mixed covalent and metallic character, simulations containing billions to trillions of atoms are now practical, reaching volumes in excess of a cubic micron. In order to obtain any new physical insights, however, it is equally important that the analysis of such systems be tractable. This is in fact possible, in large part due to our highly efficient parallel visualization code, which enables the rendering of atomic spheres, Eulerian cells, and other geometric objects in a matter of minutes, even for tens of thousands of processors and billions of atoms. After briefly describing the BlueGene/L and Roadrunner architectures, and the code optimization strategies that were employed, results obtained thus far on BlueGene/L will be reviewed, including: (1) shock compression and release of a defective EAM Cu sample, illustrating the plastic deformation accompanying void collapse as well as the subsequent void growth and linkup upon release; (2) solid-solid martensitic phase transition in shock-compressed MEAM Ga; and (3) Rayleigh-Taylor fluid instability modeled using large-scale direct simulation Monte Carlo (DSMC) simulations. I will also describe our initial experiences utilizing Cell Broadband Engine processors (developed for the Sony PlayStation 3), and planned simulation studies of ejecta and spall failure in polycrystalline metals that will be carried out when the full Petaflop Opteron/Cell Roadrunner supercomputer is assembled in mid-2008.

Biofeedback defaecation training for anismus.

PubMed

Lestàr, B; Penninckx, F; Kerremans, R

1991-11-01

Anismus, paradoxical external sphincter function, spastic pelvic floor syndrome, rectoanal dysnergia, abdomino-levator incoordination for abdominopelvic asychronism, are all due to paradoxical contraction of the striated sphincter apparatus during voiding and is characterised by prolonged and excessive straining at stool. Biofeedback is the treatment of choice and has to be introduced at an early stage. We present the results of an ambulatory approach based on the integration of simulated balloon defaecation with small (50 ml) as well as constant rectal sensation volume, defaecometry and anal manometry. The pathophysiology visualised by the patient's own anorectal pressure recordings on the screen of a personal computer is explained and corrected. Sixteen patients were treated and followed for at least 1 year. Manometric data were normal except for an increased minimum residual pressure and rectal compliance. Nine patients could not evacuate a 50 ml bolus initially. Simulated defaecation became possible in seven out of these nine patients when the bolus was increased up to the individual constant rectal sensation volume. Two patients could not evacuate this volume either, while defaecation was made much less laborious in the other seven patients. Paradoxical contraction was immediately corrected in 7/16 cases. Also, as an immediate, objective benefit of a single training session, improved defaecation of a 50 ml bolus was observed in 11 patients. This effect was preserved after 6 weeks in nine cases; symptomatic recurrence did not occur in these patients during follow-up. This method of defaecation training has many advantages as compared with sphincter training using EMG electrodes eventually performed in the absence of a desire to defaecate or in lying position.(ABSTRACT TRUNCATED AT 250 WORDS)

Free volume of mixed cation borosilicate glass sealants elucidated by positron annihilation lifetime spectroscopy and its correlation with glass properties

NASA Astrophysics Data System (ADS)

Ojha, Prasanta K.; Rath, Sangram K.; Sharma, Sandeep K.; Sudarshan, Kathi; Pujari, Pradeep K.; Chongdar, Tapas K.; Gokhale, Nitin M.

2015-01-01

The role of La+3/Sr+2 ratios, which is varied from 0.08 to 5.09, on density, molar volume, packing fraction, free volume, thermal and electrical properties in strontium lanthanum aluminoborosilicate based glass sealants intended for solid oxide fuel cell (SOFC) applications is evaluated. The studies reveal expansion of the glass network evident from increasing molar volume and decreasing packing fraction of glasses with progressive La+3 substitutions. The molecular origin of these macroscopic structural features can be accounted for by the free volume parameters measured from positron annihilation lifetime spectroscopy (PALS). The La+3 induced expanded glass networks show increased number of subnanoscopic voids with larger sizes, as revealed from the ortho-positronium (o-Ps) lifetime and its intensity. A remarkably direct correspondence between the molar volume and fractional free volume trend is established with progressive La2O3 substitution in the glasses. The effect of these structural changes on the glass transition temperature, softening temperature, coefficient of thermal expansion, thermal stability as well as electrical conductivity has been studied.

Early effect of American Academy of Pediatrics Urinary Tract Infection Guidelines on radiographic imaging and diagnosis of vesicoureteral reflux in the emergency room setting.

PubMed

Arlen, Angela M; Merriman, Laura S; Kirsch, Jared M; Leong, Traci; Scherz, Hal C; Smith, Edwin A; Broecker, Bruce H; Kirsch, Andrew J

2015-05-01

In 2011 the AAP revised practice parameters on febrile urinary tract infection in infants and children 2 to 24 months old. New imaging recommendations invigorated the ongoing debate regarding the diagnosis and management of vesicoureteral reflux. We compared evaluations in these patients with febrile urinary tract infection before and after guideline publication. During 2 separate 6-month periods 350 patients 2 to 24 months old were evaluated in the emergency room setting. Demographics, urine culture, renal-bladder ultrasound, voiding cystourethrogram and admission status were assessed. A total of 172 patients presented with initial febrile urinary tract infection in 2011, of whom 47 (27.3%) required hospitalization, while 42 of 178 (23.6%) were admitted in 2012. Admission by year did not significantly differ (p = 0.423). After guideline revision 41.2% fewer voiding cystourethrograms were done (72.1% of cases in 2011 vs 30.9% in 2012, p <0.001). A 17.2% decrease in renal-bladder ultrasound was noted (75.6% in 2011 vs 58.4% in 2012, p <0.001). Of 55 voiding cystourethrograms 21 (38.2%) were positive in 2012 compared to 36.3% in 2011 (p = 0.809). Mean ± SD maximum vesicoureteral reflux grade was unchanged in 2011 and 2012 (2.9 ± 1.2 and 2.5 ± 0.93, respectively, p = 0.109). There was no association between abnormal renal-bladder ultrasound and voiding cystourethrogram positivity (p = 0.116). AAP guidelines impacted the treatment of infants and young children with febrile urinary tract infection. We found no relationship between renal-bladder ultrasound and abnormal voiding cystourethrogram, consistent with previous findings that call ultrasound into question as the determinant for additional imaging. Whether forgoing routine voiding cystourethrogram results in increased morbidity is the subject of ongoing study. Copyright © 2015. Published by Elsevier Inc.

Computation for Electromigration in Interconnects of Microelectronic Devices

NASA Astrophysics Data System (ADS)

Averbuch, Amir; Israeli, Moshe; Ravve, Igor; Yavneh, Irad

2001-03-01

Reliability and performance of microelectronic devices depend to a large extent on the resistance of interconnect lines. Voids and cracks may occur in the interconnects, causing a severe increase in the total resistance and even open circuits. In this work we analyze void motion and evolution due to surface diffusion effects and applied external voltage. The interconnects under consideration are three-dimensional (sandwich) constructs made of a very thin metal film of possibly variable thickness attached to a substrate of nonvanishing conductance. A two-dimensional level set approach was applied to study the dynamics of the moving (assumed one-dimensional) boundary of a void in the metal film. The level set formulation of an electromigration and diffusion model results in a fourth-order nonlinear (two-dimensional) time-dependent PDE. This equation was discretized by finite differences on a regular grid in space and a Runge-Kutta integration scheme in time, and solved simultaneously with a second-order static elliptic PDE describing the electric potential distribution throughout the interconnect line. The well-posed three-dimensional problem for the potential was approximated via singular perturbations, in the limit of small aspect ratio, by a two-dimensional elliptic equation with variable coefficients describing the combined local conductivity of metal and substrate (which is allowed to vary in time and space). The difference scheme for the elliptic PDE was solved by a multigrid technique at each time step. Motion of voids in both weak and strong electric fields was examined, and different initial void configurations were considered, including circles, ellipses, polygons with rounded corners, a butterfly, and long grooves. Analysis of the void behavior and its influence on the resistance gives the circuit designer a tool for choosing the proper parameters of an interconnect (width-to-length ratio, properties of the line material, conductivity of the underlayer, etc.).

Surgical management of penile fracture and long-term outcome on erectile function and voiding.

PubMed

Hatzichristodoulou, Georgios; Dorstewitz, Annika; Gschwend, Jürgen E; Herkommer, Kathleen; Zantl, Niko

2013-05-01

Penile fracture is an emergency in urology. Surgical management is recommended, but objective data of postoperative long-term effects, especially regarding voiding and erectile function, vary. To assess long-term results of patients undergoing surgical therapy for penile fracture. Patients presenting with suspicion of penile fracture were included in this study. Diagnosis of penile fracture was made by clinical assessment and surgery performed thereafter. The defect of the tunica albuginea was closed by absorbable suture. In case of concomitant urethral lesion, the defect was repaired simultaneously. Voiding and erectile function were evaluated at long-term follow-up by mail. Patients' status before penile fracture was assessed retroactively. Erectile function was assessed by the International Index of Erectile Function questionnaire and voiding function by the International Prostate Symptom Score questionnaire. N = 34 patients were included. Penile fracture was suspected in 28/34 (82.4%) patients. Twenty-six of the 28 (92.9%) patients underwent surgery. Only less than half of confirmed fracture patients presented with the classical triad of an audible crack, detumescense, and hematoma. Fourteen of the 26 (53.8%) patients after surgery were available for follow-up. Mean follow-up was 45.6 months (range: 3.6-128.4). In 13/14 (92.9%) patients, penile fracture was confirmed by surgery. At follow-up, 7/13 (53.8%) patients had impaired erectile function, with 3/13 (23.1%) patients needing medical treatment. Four of the 13 (30.8%) patients showed deterioration of voiding including occurrence of urethral fistula. Penile fracture is an emergency for which surgery should be offered. Clinical suspicion of fracture should be high even with hematoma alone. Concomitant urethral injury is common, particularly with bilateral corporal rupture and/or initial hematuria. Preoperative counseling should include discussion of long-term erectile and voiding dysfunction, penile deformity, and urethral fistula both with and without surgery. Close patient follow-up is required. © 2013 International Society for Sexual Medicine.

Remote Infrared Thermal Sensing of Sewer Voids, Four-Year Update

NASA Astrophysics Data System (ADS)

Weil, Gary J.

1988-01-01

When a sewer caves in, it often takes the street, sidewalks, and surrounding buildings along for the ride. These collapses endanger public health and safety. Repairing a sewer before such a cave-in is obviously the preferred method. Emergency repairs cost far more than prevention measures - often millions of dollars more. Many combined sewers in the St. Louis area, as in many of America's cities, are more than 125 years old and are subject to structural failure. In 1981 alone, St. Louis had 4,000 sewer collapses and an astronomical repair bill. These and similar problems have been described as "a crisis of national proportions. The question addressed by this paper is how to detect unseen problem areas in sewer systems before they give way. At the present, progressive sewer administrations may use crawl crews to inspect sewers when problems are suspected. This can be extremely costly and dangerous, and a void around the outside of the sewer is often invisible from within. Thus, even a crawl crew can fail to detect most voids. Infrared Thermography has been found by sewer districts and independent evaluation engineering firms to be an extremely accurate method of finding sewer voids, before they can cause expensive and dangerous problems. This technique uses a non-contact, remote sensing method, with the potential for surveying large areas quickly and efficiently. This paper reviews our initial paper presented to The International Society for Optical Engineering in October of 1983 and presents an update of our experience, both successes and failures, in several large-scale void detection projects. Infrared Thermographic techniques of non-destructive testing will have major implications for cities and for the engineering profession because it promises to make the crisis of infrastructure repair and rehabilitation more manageable. Intelligent, systematic use of this relatively low cost void detection method, Infrared Thermography, may revolutionize the way sewer problems are handled in the future.

Three new 5-fold interpenetrating diamondoid frameworks constructed by rigid diimidazole and dicarboxylate ligands

NASA Astrophysics Data System (ADS)

Huo, Jianqiang; Yan, Shuai; Li, Haiqiang; Yu, Donghui; Arulsamy, Navamoney

2018-03-01

A series of three-dimensional coordination polymers, namely, [Cd(BIMB)(SCA)]n (1), [M(BIMB)(trans-CHDC)]n (2, M = Cd2+; 3, M = Co2+), where BIMB = 1,4-di(1H-imidazol-1-yl)benzene, SCA2- = succinate dianion, CHDC2- = cyclohexane-1,4-dicarboxylate dianion) are synthesized hydro/solvatothermal methods. The products are characterized by elemental analysis and single-crystal X-ray diffraction data. Both the dianion and BIMB bridge different pairs of the metal ions, the three complexes are polymeric and their three-dimensional topology feature a diamond-like metal-organic framework (MOF). Owing to the length of the two bridging ligands, moderate size voids are formed in the diamondoid networks. However, the voids are filled by mutual interpenetration of four independent equivalent frameworks in a 5-fold interpenetrating architecture, and there is no sufficient void volume available for any guest molecules. The phase purity and thermal stability of the compounds are verified by powder X-ray diffraction (PXRD) and thermogravimetric (TG) data. The solid-state fluorescence spectra for the 3d10 Cd2+ MOF's 1 and 2 reveal significant enhancement in their emission intensities in comparison to the non-metallated BIMB. The enhanced emission is attributed to perturbation of intra-ligand emission states due to Cd2+ coordination.

Effect of water potential and void ratio on erodibility for agricultural soils

USDA-ARS?s Scientific Manuscript database

Soil erodibility has confounded researchers for decades. Difficulties arise with initiation of motion, pore-water status, physical, and perhaps biological, material properties and type of applied energy (i.e. rainfall, runoff, freeze/thaw, wind). Though specific tests have been developed to determin...

Voiding and sexual dysfunctions after pelvic fracture urethral injuries treated with either initial cystostomy and delayed urethroplasty or immediate primary urethral realignment.

PubMed

Aşci, R; Sarikaya, S; Büyükalpelli, R; Saylik, A; Yilmaz, A F; Yildiz, S

1999-08-01

The aim of this study is to evaluate the effects of the different immediate treatment modalities on the sexual and voiding functions in pelvic fracture urethral injuries. The records of 38 male patients with traumatic posterior urethral injuries were reviewed, 18 of whom were treated by initial suprapubic cystostomy and delayed repair (Group 1), and 20 by primary urethral realignment (Group 2). Types of pelvic fractures and urethral injuries were classified according to surgical and radiological findings. Long-term voiding functions were determined by the patient questionnaire, residual urine and uroflow. Sexual functions were also determined by the patient questionnaire and a penile duplex ultrasound study. Mean follow-ups of Groups 1 and 2 were 37 and 39 months, respectively. Membranous urethral disruption extending to the urogenital diaphragm was the most frequent urethral injury (type 3), with incidences of 66.7% and 77.7%, respectively. There were no statistically significant differences in mean age, incidence of pelvic fracture types and urethral injury types between groups (p > 0.05). After the immediate treatments, 16.7% and 55% of the patients regained normal urination, and stricture developed in 83.3% and 45% of the patients, respectively. In 44.4% of the patients in Group 1 and 10% in Group 2, urethral strictures required open urethroplasty (p < 0.05). Erectile impotence before urethroplasty in 17.6% and 20%, anejaculation after urethroplasty in 17.6% and 15% and incontinence in 5.6% and 10% of the patients were found in Groups 1 and 2, respectively (p > 0.05). However, 88.8% and 90% of patients eventually achieved normal urination with complete continence. Sexual and voiding dysfunction after pelvic fracture posterior urethral injury seem to be the result of the injury itself, not of the immediate treatment modalities. In urethral disruption injuries, primary urethral realignment seems more favourable than suprapubic cystostomy and delayed repair.

Free Volume Structure of Acrylic-Type Dental Nanocomposites Tested with Annihilating Positrons.

PubMed

Shpotyuk, Olha; Ingram, Adam; Shpotyuk, Oleh

2016-12-01

Positron annihilation spectroscopy in lifetime measuring mode exploring conventional fast-fast coincidence ORTEC system is employed to characterize free volume structure of commercially available acrylic-type dental restorative composite Charisma® (Heraeus Kulzer GmbH, Germany). The measured lifetime spectra for uncured and light-cured composites are reconstructed from unconstrained x3-term fitting and semi-empirical model exploring x3-x2-coupling decomposition algorithm. The governing channel of positron annihilation in the composites studied is ascribed to mixed positron-Ps trapping, where Ps decaying in the third component is caused entirely by input from free-volume holes in polymer matrix, while the second component is defined by free positron trapping in interfacial free-volume holes between filler nanoparticles and surrounded polymer matrix. Microstructure scenario of the photopolymerization shrinkage includes cross-linking of structural chains in polymer matrix followed by conversion of bound positron-electron (positronium) traps in positron-trapping interfacial free-volume voids in a vicinity of agglomerated filler nanoparticles.

Loxoprofen sodium treatment for elderly men with refractory nocturia: effect on night-time urine production.

PubMed

Okada, Shinsuke; Watanabe, Hideki; Kojima, Yoshiyuki; Yanai, Yoshimasa; Sasaki, Shoichi; Kohri, Kenjiro

2008-05-01

We evaluated the efficacy of loxoprofen sodium for refractory nocturia. Twelve men (mean age, 75.1 +/- 5.7) with nocturia were enrolled in this study. All patients received 60 mg loxoprofen sodium prior to sleeping at night for 14 days. Nine of 12 patients (75%) felt more satisfaction than previous treatments. Patients were grouped into a loxoprofen sodium-effective (n = 7) and ineffective groups (n = 5) based on the results of the frequency-volume chart. In the effective group, interestingly, night-time urine volume showed significant reduction (P < 0.05). On the other hand, the average single voided volume at night and 24-h urine volume showed no significant change. There was a statistically significant difference in the night-time urine volume after treatment between groups (P < 0.01). Loxoprofen sodium is an effective treatment for some patients with refractory nocturia. The main effect mechanism of loxoprofen sodium may involve the reduction of night-time urine production.

Probabilistic micromechanics of woven ceramic matrix composites

NASA Astrophysics Data System (ADS)

Goldsmith, Marlana

Woven ceramic matrix composites are a special class of composite materials that are of current interest for harsh thermo-structural conditions such as those encountered by hypersonic vehicle systems and turbine engine components. Testing of the materials is expensive, especially as materials are constantly redesigned. Randomness in the tow architecture, as well as the randomly shaped and spaced voids that are produced as a result of the manufacturing process, are features that contribute to variability in stiffness and strength. The goal of the research is to lay a foundation in which characteristics of the geometry can be translated into material properties. The research first includes quantifying the architectural variability based on 2D micrographs of a 5 harness satin CVI (Chemical Vapor Infiltration) SiC/SiC composite. The architectural variability is applied to a 2D representative volume element (RVE) in order to evaluate which aspects of the architecture are important to model in order to capture the variability found in the cross sections. Tow width, tow spacing, and tow volume fraction were found to have some effect on the variability, but voids were found to have a large influence on transverse stiffness, and a separate study was conducted to determine which characteristics of the voids are most critical to model. It was found that the projected area of the void perpendicular to the transverse direction and the number of voids modeled had a significant influence on the stiffness. The effect of varying architecture on the variability of in-plane tensile strength was also studied using the Brittle Cracking Model for Concrete in the commercial finite element software, Abaqus. A maximum stress criterion is used to evaluate failure, and the stiffness of failed elements is gradually degraded such that the energy required to open a crack (fracture energy) is dissipated during this degradation process. While the varying architecture did not create variability in the in-plane stiffness, it does contribute significantly to the variability of in-plane strength as measured by a 0.02% offset method. Applying spatially random strengths for the constituents did not contribute to variability in strength as measured by the 0.02% offset. The results of this research may be of interest to those designing materials, as well as those using the material in their design. Having an idea about which characteristics of the architecture affect variability in stiffness may provide guidance to the material designer with respect to which aspects of the architecture can be controlled or improved to decrease the variability of the material properties. The work will also be useful to those desiring to use the complex materials by determining how to link the architectural properties to the mechanical properties with the ultimate goal of reducing the required number of tests.

The effect of distribution of second phase on dynamic damage

DOE PAGES

Fensin, Saryu J.; Jones, David R.; Walker, Emily K.; ...

2016-08-28

For ductile metals, dynamic fracture occurs principally through void nucleation, growth, and coalescence at heterogeneities in the microstructure. Previous experimental research on high purity metals has shown that microstructural features, such as grain boundaries, inclusions, vacancies, and heterogeneities, can act as initial void nucleation sites. In addition, other research on two-phase materials has also highlighted the importance of the properties of a second phase itself in determining the dynamic response of the overall material. But, previous research has not investigated the effects of the distribution of a second phase on damage nucleation and evolution. To approach this problem in amore » systematic manner, two copper alloys with 1% lead materials, with the same Pb concentration but different Pb distributions, have been investigated. A new CuPb alloy was cast with a more homogeneous distribution of Pb as compared to a CuPb where the Pb congregated in large “stringer” type configurations. These materials were shock loaded at ~1.2 GPa and soft recovered. In-situ free surface velocity information, and post mortem metallography, reveals that even though the spall strength of both the materials were similar, the total extent and details of damage in the materials varied by 15%. This then suggests that altering the distribution of Pb in the Cu matrix leads to the creation of more void nucleation sites and also changed the rate of void growth.« less

Evolution of the cosmic web

NASA Astrophysics Data System (ADS)

Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.; Frenk, Carlos S.

2014-07-01

The cosmic web is the largest scale manifestation of the anisotropic gravitational collapse of matter. It represents the transitional stage between linear and non-linear structures and contains easily accessible information about the early phases of structure formation processes. Here we investigate the characteristics and the time evolution of morphological components. Our analysis involves the application of the NEXUS Multiscale Morphology Filter technique, predominantly its NEXUS+ version, to high resolution and large volume cosmological simulations. We quantify the cosmic web components in terms of their mass and volume content, their density distribution and halo populations. We employ new analysis techniques to determine the spatial extent of filaments and sheets, like their total length and local width. This analysis identifies clusters and filaments as the most prominent components of the web. In contrast, while voids and sheets take most of the volume, they correspond to underdense environments and are devoid of group-sized and more massive haloes. At early times the cosmos is dominated by tenuous filaments and sheets, which, during subsequent evolution, merge together, such that the present-day web is dominated by fewer, but much more massive, structures. The analysis of the mass transport between environments clearly shows how matter flows from voids into walls, and then via filaments into cluster regions, which form the nodes of the cosmic web. We also study the properties of individual filamentary branches, to find long, almost straight, filaments extending to distances larger than 100 h-1 Mpc. These constitute the bridges between massive clusters, which seem to form along approximatively straight lines.

Clinical comparision of intravesical hyaluronic acid and hyaluronic acid-chondroitin sulphate therapy for patients with bladder pain syndrome/interstitital cystitis.

PubMed

Gülpınar, Omer; Kayış, Aytaç; Süer, Evren; Gökçe, Mehmet İlker; Güçlü, Adil Güçal; Arıkan, Nihat

2014-09-01

Patients with a history of bladder pain syndrome/interstitial cystitis (BPS/IC) and who responded poorly or unsatisfactorily with previous treatment were compared taking intravesical hyaluronic acid (HA) or hyaluronic acid-chondroitin sulphate (HA-CS). Patients were treated with intravesical instillation with 50 mL sterile sodium hyalurinic acid (Hyacyst, Syner-Med, Surrey, UK) (n = 32) and sodium hyaluronate 1.6% sodium chondroitin sulphate 2% (Ialuril, Aspire Pharma, UK) (n = 33). Intravesical instillations were performed weekly in first month, every 15 days in the second month and monthly in third and fourth months, for a total of 8 doses. Patients were evaluated using a visual analog pain scale (VAS), interstitial cystitis symptom index (ICSI), interstitial cystitis problem index (ICPI), voiding diary for frequency/nocturia, cystometric bladder capacity and voided volume at the beginning and at 6 months. All patients had a potassium sensitivity test (PST) initially. Wilcoxon and Mann-Whitney U tests were used for statistical analysis. In total, 53 patients met the study criteria. There were 30 patients in the HA-CS group (mean age: 48.47) and 23 patients in the HA group (mean age: 49.61) (p > 0.05). The initial PST was positive in 71.7% patients (38/53) overall with no difference between groups (p > 0.05). Responses for VAS, ICCS, ICPS, 24-hour frequency/nocturia statistically improved in both groups at 6 months. There was no significant difference in symptomatic improvement (p > 0.05). Eight patients had mild adverse events. HA and HA/CS instillation can be effective in BPS/IC patients who do not respond to conservative treatment. An important limitation of our study is that the HA dosage of the 2 treatment arms were different. It would be more appropriate with same HA dosage in both groups; however, there was no commercially available glycosaminoglycan (GAG) substance with same HA dosage for single and combination therapy. Large, long-term randomized studies are required to determine if there is a difference between these treatments.

Effects of cement alkalinity, exposure conditions and steel-concrete interface on the time-to-corrosion and chloride threshold for reinforcing steel in concrete

NASA Astrophysics Data System (ADS)

Nam, Jingak

Effects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH measurement of concrete pore water. Once specimens were fabricated and exposed to a corrosive chloride solution, various experimental techniques were employed to determine time-to-corrosion, chloride threshold, diffusion coefficient and void density along the rebar trace as well as pore water pH. Based upon the resultant data, several findings related to the above parameters have been obtained as summarized below. First, time for the corrosion initiation was longest for G109 concrete specimens with high alkalinity cement (HA). Also, chloride threshold increased with increasing time-to-corrosion and cement alkalinity. Consequently, the HA specimens exhibited the highest chloride threshold compared to low and normal alkalinity ones. Second, high temperature and temperature variations reduced time-to-corrosion of reinforcing steel in concrete since chloride diffusion was accelerated at higher temperature and possibly by temperature variations. The lowest chloride threshold values were found for outdoor exposed specimens suggesting that variation of RH or temperature (or both) facilitated rapid chloride diffusion. Third, an elevated time-to-corrosion and chloride threshold values were found for the wire brushed steel specimens compared to as-received ones. The higher ratio of [OH-]/[Fe n+] on the wire brushed steel surface compared to that of as-received case can be the possible cause because the higher ratio of this parameter enables the formation of a more protective passive film on the rebar. Fourth, voids at the steel-concrete interface facilitated passive film breakdown and onset of localized corrosion. This tendency for corrosion initiation increased in proportion to void size irrespective of specimen type. Also, [Cl -]th decreased with increasing void diameter. In addition, new ex-situ leaching method for determining concrete pore water alkalinity was developed.

Undetected penetrating bladder injuries presenting as a spontaneously expulsed bullet during voiding: a rare entity and review of the literature.

PubMed

Kuy, SreyRam; Somberg, Lewis B; Paul, Jasmeet; Brown, Nathaniel; Saving, Allegra; Codner, Panna A

2013-09-01

Patients presenting with a penetrating missile lodged in the pelvis are at risk for having a urinary tract injury. Once in the bladder, the missile can become impacted in the urethra, causing retention that requires extraction. Rarely, the missile can be expulsed spontaneously through the urethra. To describe the world literature regarding undetected penetrating bladder injuries presenting as spontaneously voided bullets and to contribute an additional case to the literature. We present a case report of a 37-year-old man who sustained a gunshot wound to the right buttock, with an undetected urinary system injury and subsequent spontaneous voiding of a bullet. There have been <10 cases reported in the literature of spontaneously expulsed bullets from the urethra, all of which were undetected injuries on initial presentation. Physicians should be aware of the potential for undetected urinary tract injuries in patients with penetrating missiles to the pelvis and understand the appropriate evaluation and management strategies for these injuries. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of hydrogen on void initiation in tensile test of carbon steel JIS-S25C

NASA Astrophysics Data System (ADS)

Sugawa, S.; Tsutsumi, N.; Oda, K.

2018-06-01

In order to investigate the effect of hydrogen on tensile fracture mechanism of a carbon steel, tensile tests were conducted. Pre-strain specimens (0%, 5% and 10%) were used to study the effect of hydrogen content, since saturated hydrogen content in specimens increases in increasing dislocation density. The tensile strength and the yield stress of hydrogen specimens were almost the same as uncharged. In contrast, the reduction of area of hydrogen charged specimens was smaller than that of uncharged. To reveal the reasons of decrease of the reduction of area, the fracture surface and longitudinal cross section near the fracture surface were observed. On the fracture surface of uncharged specimens, only dimples were observed. On the other hand, dimples and flat fracture surface were observed on the fracture surface of hydrogen charged. On the longitudinal cross section of hydrogen charged specimens, many voids were observed compared to uncharged. From these observations, it is showed that hydrogen gives a rise to the increase of voids and the hydrogen charged specimens break without sufficient necking, thus hydrogen makes the reduction of area smaller.

Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

DOE PAGES

Wiens, Roger C.; Rubin, David M.; Goetz, Walter; ...

2017-02-21

Voids and hollow spheroids between ~1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302–305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1–4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only onemore » hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. The origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Though some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions.« less

Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

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

Wiens, Roger C.; Rubin, David M.; Goetz, Walter

Voids and hollow spheroids between ~1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302–305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1–4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only onemore » hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. The origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Though some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions.« less

Evaluation of prenatal hydronephrosis: novel criteria for predicting vesicoureteral reflux on ultrasonography.

PubMed

Lee, Nora G; Rushton, H Gil; Peters, Craig A; Groves, Danja S; Pohl, Hans G

2014-09-01

Radiographic evaluation for prenatal hydronephrosis often includes voiding cystourethrography to ascertain whether vesicoureteral reflux is present. We sought to determine whether use of voiding cystourethrography could be limited to those patients at greatest risk for vesicoureteral reflux. We hypothesized that vesicoureteral reflux could be predicted by findings on renal/bladder ultrasonography of hydroureter, renal dysmorphia and/or duplication. We reviewed the records of patients with prenatal hydronephrosis who underwent initial postnatal ultrasonography and voiding cystourethrography during a 3-year period. The presence of vesicoureteral reflux on voiding cystourethrogram was correlated to ultrasound findings, including hydronephrosis grade, presence of hydroureter, renal dysmorphia or duplication, with ultrasound considered positive for any of the latter 3 findings. Of 262 patients 47 (18%) had vesicoureteral reflux. Ultrasound was positive in 24 of 29 patients (83%) with high grade reflux and 12 of 18 (67%) with low grade reflux. If ultrasonography showed any of the 3 positive findings, the odds ratio of detecting vesicoureteral reflux was 8.07 (95% CI 3.86, 16.87). Using these criteria, among all cases of prenatal hydronephrosis 5 (2%) with high grade vesicoureteral reflux and 6 (2%) with low grade reflux would have been missed. Among the 47 cases of reflux overall 5 of 29 high grade (17%) and 6 of 18 low grade cases (33%) would have been missed. By using ultrasonography criteria of hydroureter, duplication and renal dysmorphia for patients with prenatal hydronephrosis, vesicoureteral reflux can be detected more specifically. Using our criteria, 165 of 262 voiding cystourethrograms (63%) could have been avoided in patients with prenatal hydronephrosis during a 3-year period. Reducing these evaluations may decrease risks regarding radiation exposure, family anxiety and health care costs. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Structural Investigations of Fibers and Films of Poly(p-phenylene benzobisthiazole). Volume 1

DTIC Science & Technology

1982-05-01

differential scanning calorimetry, is unrelated to the diffuse scattered intensity [45]. Cellulose acetate which is known to be noncrystalline exhibits a high...Weidinger [45] found the diffuse scattered intensity increased with decreasing density and therefore, increasing void fraction, in air swollen cellulose ... Cellulose , and Poly(y-Benzyl-L-Glutamate)." J. Polym. Sci., Polym. Phys. Ed., 18, 663-682 (1980). 39. C.H. Kao and J.M. Ottino, personal communication

Technology of Fast Spark Gaps

DTIC Science & Technology

1989-09-01

material, reticulated vitreous carbon , that consists of an open-cell, rigid carbon "foam." This material was developed in the mid- 1970’s as a filter...These halides are excellent emitters of photoelectrons. 33 About 90 percent of the volume of reticulated vitreous carbon is void. Thus an electrical...for fluids and as a scaffold for work at high temperatures or with corrosive agents. A relatively fine mesh of vitreous carbon , perhaps about four

Hydrogen Storage in Metal Hydrides

DTIC Science & Technology

1990-08-01

TitlePage 1. Properties of Reticulated Carbon Foam 26 2. Hydrogen Storage Capacity of Various Metal Hydrides 27 iv INTRODUCTION This is the final technical...pores, and results in coating of only the surface. The substrate for the fabrication of the magnesium foam was a reticulated carbon foam. This...material is an open-pore foam composed solely of vitreous carbon . It has an exceptionally high void volume (97%) and a high surface area, combined with self

Thermoplastic-carbon fiber hybrid yarn

NASA Technical Reports Server (NTRS)

Ketterer, M. E.

1984-01-01

Efforts were directed to develop processing methods to make carbon fiber/thermoplastic fiber preforms that are easy to handle and drapeable, and to consolidate them into low void content laminates. The objectives were attained with the development of the hybrid yarn concept; whereby, thermoplastic fiber can be intimately intermixed with carbon fiber into a hybrid yarn. This was demonstrated with the intermixing of Celion 3000 with a Celanese liquid crystal polymer fiber, polybutylene terepthalate fiber, or polyetheretherketone fiber. The intermixing of the thermoplastic matrix fiber and the reinforcing carbon fiber gives a preform that can be easily fabricated into laminates with low void content. Mechanical properties of the laminates were not optimized; however, initial results indicated properties typical of a thermoplastic/carbon fiber composites prepared by more conventional methods.

Summary and evaluation: fuel dynamics loss-of-flow experiments (tests L2, L3, and L4)

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

Barts, E.W.; Deitrich, L.W.; Eberhart, J.G.

1975-09-01

Three similar experiments conducted to support the analyses of hypothetical LMFBR unprotected-loss-of-flow accidents are summarized and evaluated. The tests, designated L2, L3, and L4, provided experimental data against which accident-analysis codes could be compared, so as to guide further analysis and modeling of the initiating phases of the hypothetical accident. The tests were conducted using seven-pin bundles of mixed-oxide fuel pins in Mark-II flowing-sodium loops in the TREAT reactor. Test L2 used fresh fuel. Tests L3 and L4 used irradiated fuel pins having, respectively, ''intermediate-power'' (no central void) and ''high-power'' (fully developed central void) microstructure. 12 references. (auth)

New treatments for incontinence.

PubMed

MacLachlan, Lara S; Rovner, Eric S

2015-07-01

Urinary incontinence (UI) is a common, yet underdetected and under-reported, health problem that can significantly affect quality of life. UI may also have serious medical and economic ramifications for untreated or undertreated patients, including perineal dermatitis, worsening of pressure ulcers, urinary tract infections, and falls. To prevent incontinence, the urethral sphincter must maintain adequate closure to resist the flow of urine from the bladder at all times until voluntary voiding is initiated and the bladder must accommodate increasing volumes of urine at a low pressure. UI can be categorized as a result of urethral underactivity (stress UI), bladder overactivity (urge UI), a combination of the 2 (mixed incontinence), or urethral overactivity/bladder underactivity (overflow incontinence). The main goal of therapy for the management of UI is to reduce the number of UI episodes, prevent complications, and, if possible, restore continence. This review highlights the existing treatment of stress, urge, mixed, and overflow UI in adult men and women and discusses many of the novel treatments including potential future or emerging therapies. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Educational Brief: Using Space for a Better Foundation on Earth Mechanics of Granular Materials

NASA Technical Reports Server (NTRS)

Dooling, Dave (Editor)

2002-01-01

Soils are three-phase composite materials that consist of soil, solid particles, and voids filled with water and/or air. Based on the particle-size distribution, they are generally classified as fine-grained (clays and plastic silts) and coarse-grained soils (nonplastic silts, sand, and gravel). Soil's resistance to external loadings is mainly derived from friction between particles and cohesion. Friction resistance is due to particles' surface-to-surface friction, interlocking, crushing, rearrangement, and dilation (or expansion) during shearing. Cohesion can be due to chemical cementation between particles, electrostatic and electromagnetic forces, and soil-water reaction and equilibrium. The basic factor responsible for the strength of coarse-grained soils is friction. Cohesion can be ignored. This educational brief focuses on measuring shear strength of sands (typical example of coarse-grained soils) where, for the same material, packing density is a main factor to be considered when one asks about the shear strength value. As the external load is applied, the soil's resistance is attained through shearing resistance, which causes the soil volume to increase (expand) or decrease (compress) depending on the initial packing density.

Effect of Selective Prostaglandin E2 EP2 Receptor Agonist CP-533,536 on Voiding Efficiency in Rats with Midodrine-Induced Functional Urethral Obstruction.

PubMed

Kurihara, Ryoko; Imazumi, Katsunori; Takamatsu, Hajime; Ishizu, Kenichiro; Yoshino, Taiji; Masuda, Noriyuki

2016-05-01

We investigated the effect of the selective prostaglandin E2 EP2 receptor agonist CP-533,536 on voiding efficiency in rats with midodrine-induced functional urethral obstruction. The effect of CP-533,536 (0.03-0.3 mg/kg, intravenous [i.v.]) on urethral perfusion pressure (UPP) was investigated in anesthetized rats pre-treated with midodrine (1 mg/kg, i.v.), which forms an active metabolite that acts as an α1 -adrenoceptor agonist. The effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on cystometric parameters was also investigated in anesthetized rats. In addition, the effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on residual urine volume (RV) and voiding efficiency (VE) was investigated in conscious rats treated with midodrine (1 mg/kg, i.v.). CP-533,536 dose-dependently decreased UPP elevated by midodrine in anesthetized rats. In contrast, CP-533,536 did not affect maximum voiding pressure, intercontraction interval, or intravesical threshold pressure. In conscious rats, midodrine (1 mg/kg, i.v.) markedly increased RV and reduced VE. CP-533,536 dose-dependently ameliorated increases in RV and decreases in VE induced by midodrine. These results suggest that a selective EP2 receptor agonist could ameliorate the elevation of RV and improve the reduction of VE in rats with functional urethral obstruction caused by stimulation of α1 -adrenoceptors. The mechanism of action might be not potentiation of bladder contraction but rather preferential relief of urethral constriction. © 2014 Wiley Publishing Asia Pty Ltd.

Near infrared spectroscopy evaluation of bladder function: the impact of skin pigmentation on detection of physiologic change during voiding

NASA Astrophysics Data System (ADS)

Shadgan, Babak; Stothers, Lynn; Molavi, Behnam; Mutabazi, Sharif; Mukisa, Ronald; Macnab, Andrew

2015-02-01

Background: Prior research indicates the epidermal pigment layer of human skin (Melanin) has a significant absorption coefficient in the near infra-red (NIR) region; hence attenuation of light in vivo is a potential confounder for NIR spectroscopy (NIRS). A NIRS method developed for transcutaneous evaluation of bladder function is being investigated as a means of improving the burden of bladder disease in sub-Saharan Africa. This required development of a simple wireless NIRS device suitable for use as a screening tool in patients with pigmented skin where the NIR light emitted would penetrate through the epidermal pigment layer and return in sufficient quantity to provide effective monitoring. Methods: Two healthy subjects, one with pigmented skin and one with fair skin, were monitored as they voided spontaneously using the prototype transcutaneous NIRS device positioned over the bladder. The device was a self-contained wireless unit with light emitting diodes (wavelengths 760 and 850 nanometres) and interoptode distance of 4cm. The raw optical data were transmitted to a laptop where graphs of chromophore change were generated with proprietary software and compared between the subjects and with prior data from asymptomatic subjects. Results: Serial monitoring was successful in both subjects. Voiding volumes varied between 350 and 380 cc. In each subject the patterns of chromophore change, trend and magnitude of change were similar and matched the physiologic increase in total and oxygenated hemoglobin recognized to occur in normal bladder contraction during voiding. Conclusions: Skin pigmentation does not compromise the ability of transcutaneous NIRS to interrogate physiologic change in the bladder during bladder contraction in healthy subjects.

NanoXCT: a novel technique to probe the internal architecture of pharmaceutical particles.

PubMed

Wong, Jennifer; D'Sa, Dexter; Foley, Matthew; Chan, John Gar Yan; Chan, Hak-Kim

2014-11-01

To demonstrate the novel application of nano X-ray computed tomography (NanoXCT) for visualizing and quantifying the internal structures of pharmaceutical particles. An Xradia NanoXCT-100, which produces ultra high-resolution and non-destructive imaging that can be reconstructed in three-dimensions (3D), was used to characterize several pharmaceutical particles. Depending on the particle size of the sample, NanoXCT was operated in Zernike Phase Contrast (ZPC) mode using either: 1) large field of view (LFOV), which has a two-dimensional (2D) spatial resolution of 172 nm; or 2) high resolution (HRES) that has a resolution of 43.7 nm. Various pharmaceutical particles with different physicochemical properties were investigated, including raw (2-hydroxypropyl)-beta-cyclodextrin (HβCD), poly (lactic-co-glycolic) acid (PLGA) microparticles, and spray-dried particles that included smooth and nanomatrix bovine serum albumin (BSA), lipid-based carriers, and mannitol. Both raw HβCD and PLGA microparticles had a network of voids, whereas spray-dried smooth BSA and mannitol generally had a single void. Lipid-based carriers and nanomatrix BSA particles resulted in low quality images due to high noise-to-signal ratio. The quantitative capabilities of NanoXCT were also demonstrated where spray-dried mannitol was found to have an average void volume of 0.117 ± 0.247 μm(3) and average void-to-material percentage of 3.5%. The single PLGA particle had values of 1993 μm(3) and 59.3%, respectively. This study reports the first series of non-destructive 3D visualizations of inhalable pharmaceutical particles. Overall, NanoXCT presents a powerful tool to dissect and observe the interior of pharmaceutical particles, including those of a respirable size.

First-void urine: A potential biomarker source for triage of high-risk human papillomavirus infected women.

PubMed

Van Keer, Severien; Pattyn, Jade; Tjalma, Wiebren A A; Van Ostade, Xaveer; Ieven, Margareta; Van Damme, Pierre; Vorsters, Alex

2017-09-01

Great interest has been directed towards the use of first-void urine as a liquid biopsy for high-risk human papillomavirus DNA testing. Despite the high correlations established between urinary and cervical infections, human papillomavirus testing is unable to distinguish between productive and transforming high-risk infections that have the tendency to progress to cervical cancer. Thus far, investigations have been primarily confined to the identification of biomarkers for triage of high-risk human papillomavirus-positive women in cervicovaginal specimens and tissue biopsies. This paper reviews urinary biomarkers for cervical cancer and triage of high-risk human papillomavirus infections and elaborates on the opportunities and challenges that have emerged regarding the use of first-void urine as a liquid biopsy for the analysis of both morphological- (conventional cytology and novel immunohistochemical techniques) and molecular-based (HPV16/18 genotyping, host/viral gene methylation, RNA, and proteins) biomarkers. A literature search was performed in PubMed and Web of Science for studies investigating the use of urine as a biomarker source for cervical cancer screening. Five studies were identified reporting on biomarkers that are still in preclinical exploratory or clinical assay development phases and on assessments of non-invasive (urine) samples. Although large-scale validation studies are still needed, we conclude that methylation of both host and viral genes in urine has been proven feasible for use as a molecular cervical cancer triage and screening biomarker in phase two studies. This is especially promising and underscores our hypothesis that human papillomavirus DNA and candidate human and viral biomarkers are washed away with the initial, first-void urine, together with exfoliated cells, debris and impurities that line the urethra opening. Similar to the limitations of self-collected cervicovaginal samples, first-void urine will likely not fulfil the high-quality cellularity standards required for morphological biomarkers. Molecular biomarkers will likely overcome this issue to yield high-throughput, objective, and reproducible results. When using proper sampling, transport, storage, preanalytical biomarker concentration techniques, and clinically validated assays, first-void urine is expected to be a valuable source of molecular biomarkers for cervical cancer screening. Furthermore, as first-void urine can be easily and non-invasively collected, it is a highly preferred technique among women and offers the ability to test both primary high-risk human papillomavirus and biomarkers in the same sample. In addition, the use of first-void urine confers opportunities to reduce loss-to follow-up and non-adherence to screening subjects. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

X-ray Computed Tomography Imaging of the Microstructure of Sand Particles Subjected to High Pressure One-Dimensional Compression

PubMed Central

al Mahbub, Asheque; Haque, Asadul

2016-01-01

This paper presents the results of X-ray CT imaging of the microstructure of sand particles subjected to high pressure one-dimensional compression leading to particle crushing. A high resolution X-ray CT machine capable of in situ imaging was employed to capture images of the whole volume of a sand sample subjected to compressive stresses up to 79.3 MPa. Images of the whole sample obtained at different load stages were analysed using a commercial image processing software (Avizo) to reveal various microstructural properties, such as pore and particle volume distributions, spatial distribution of void ratios, relative breakage, and anisotropy of particles. PMID:28774011

X-ray Computed Tomography Imaging of the Microstructure of Sand Particles Subjected to High Pressure One-Dimensional Compression.

PubMed

Al Mahbub, Asheque; Haque, Asadul

2016-11-03

This paper presents the results of X-ray CT imaging of the microstructure of sand particles subjected to high pressure one-dimensional compression leading to particle crushing. A high resolution X-ray CT machine capable of in situ imaging was employed to capture images of the whole volume of a sand sample subjected to compressive stresses up to 79.3 MPa. Images of the whole sample obtained at different load stages were analysed using a commercial image processing software (Avizo) to reveal various microstructural properties, such as pore and particle volume distributions, spatial distribution of void ratios, relative breakage, and anisotropy of particles.

The origin of 17O-depleted barite in Neoproterozoic cap carbonates in South China: A sedimentological perspective

NASA Astrophysics Data System (ADS)

Zhou, C.; Bao, H.; Yuan, X.

2009-12-01

Barite deposits are known from the Marinoan cap carbonate sequence in NW Africa, NW Canada, and many other localities worldwide, including South China, where the barite has been found to have distinct, non-mass-dependent depletion in 17O. It has been proposed that the negative anomalies most likely reflect an extremely high pCO2 atmosphere at the initiation of a global glacial meltdown. While widespread in occurrence and distinct in isotopic composition, the barite’s origin remains elusive. Field observation shows that the 17O-anomalous barite occurs only at one specific horizon/surface of the cap dolostone. A satisfying formation model based on geochemical data for the barite must corroborate evidence from geological, tectonic, sedimentological, and petrographic contexts. The Nantuo glacial deposit (Marinoan in age) and its cap carbonate occur widely on the Yangtze Block of South China. The thickness of the Nantuo tillites increases evidently from the shallow platform to basinal settings. The overlying cap carbonates, consisting mainly of dolostone, however, are generally around 3~4 meters thick and remain relatively stable on the Yangtze Block. There is a widespread occurrence of voids and cavities in the lower part of cap dolostones, in both shallow platform facies and transitional zones of the Yangtze Block. Barite deposits occur as fans or coatings on pre-existing surfaces or on walls of voids and fractures, probably marking a synchronous event affecting the entire Yangtze Block. Void and cavity fills generally start with aragonite crystal fans and barite fans, followed by opal (silica) or quartz, or calcite. The remaining space was finally filled with large blocky calcite crystals in shallower settings or pyrite crystals in deeper settings. We propose that the voids and cavities are the result of carbonate dissolution after the initial deposition of cap dolostones. The dissolution may imply a regional or even a global sedimentation hiatus during the deposition of Marinoan cap carbonates. One possibility is that the initially deposited cap carbonate may have been uplifted into a zone influenced by meteoric water due to glacioeustasy and lithospheric rebound as a result of a quick unloading of a massive continental ice cap on the Yangtze Block. Karstic dissolution has also been recognized in cap dolostones in NW Africa and NW Canada. While the voids and cavities in South China may be of a similar karst origin as those in NM Africa, sedimentological evidence, together with multiple sulfur and oxygen isotope data, suggests that the precipitation of the barite in South China may be related to an episode of free Ba2+ supply from deep, anoxic water, in association with a transgression (instead of an sea-level fall) after a karst dissolution. Thus, we suggest that SO42- was present in seawater prior to the beginning of Marinoan meltdown. It was the Ba2+ supply that limited the occurrence of barite to specific stratigraphic horizons in the cap carbonates. If the above inference is true, the 17O-depleted barite has recorded an atmospheric/hydrological condition well after the initial meltdown of the Marinoan "snowball" Earth.

Void effect on mechanical properties of copper nanosheets under biaxial tension by molecular dynamics method

NASA Astrophysics Data System (ADS)

Yang, Zailin; Yang, Qinyou; Zhang, Guowei; Yang, Yong

2018-03-01

The relationship between void size/location and mechanical behavior under biaxial loading of copper nanosheets containing voids are investigated by molecular dynamics method. The void location and the void radius on the model are discussed in the paper. The main reason of break is discovered by the congruent relationship between the shear stress and its dislocations. Dislocations are nucleated at the corner of system and approached to the center of void with increased deformation. Here, a higher stress is required to fail the voided sheets when smaller voids are utilized. The void radius influences the time of destruction. The larger the void radius is, the lower the shear stress and the earlier the model breaks. The void location impacts the dislocation distribution.

Extended Burnup Credit for BWR Spent Nuclear Fuel in Storage and Transportation Systems

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

Ade, Brian J; Bowman, Stephen M; Gauld, Ian C

2015-01-01

[Full Text] Oak Ridge National Laboratory and the United States Nuclear Regulatory Commission have initiated a multiyear project to investigate the application of burnup credit (BUC) for boiling-water reactor (BWR) fuel in storage and transportation casks. This project includes two phases. The first phase investigates the applicability of peak reactivity methods currently used for spent fuel pools to spent fuel storage and transportation casks and the validation of reactivity (k eff) calculations and depleted fuel compositions. The second phase focuses on extending BUC beyond peak reactivity. This paper documents work performed to date, investigating some aspects of extended BUC, andmore » it also describes the plan to complete the evaluations. The technical basis for application of peak reactivity methods to BWR fuel in storage and transportation systems is presented in a companion paper. Two reactor operating parameters are being evaluated to establish an adequate basis for extended BWR BUC, including investigation of the axial void profile effect and the effect of control blade utilization during operation. A detailed analysis of core simulator data for one cycle of an operating BWR plant was performed to determine the range of void profiles and the variability of the profile experienced during irradiation. While a single cycle does not provide complete data, the data obtained are sufficient to use to determine the primary effects and identify conservative modeling approaches. Using data resulting from a single cycle, the axial void profile is studied by first determining the temporal fidelity necessary in depletion modeling, and then using multiple void profiles to examine the effect of the void profile on cask reactivity. The results of these studies are being used to develop recommendations for conservatively modeling the void profile effects for BWR depletion calculations. The second operational parameter studied is control blade exposure. Control blades are inserted in various locations and at varying degrees during BWR operation based on the reload design. The presence of control blades during depletion hardens the neutron spectrum locally due to both moderator displacement and introduction of a thermal neutron absorber. The reactivity impact of control blade presence is investigated herein, as well as the effect of multiple (continuous and intermittent) exposure periods. The coupled effects of control blade presence on power density, void profile, or burnup profile have not been considered to date but will be addressed in future work.« less

Immunochemical Investigations of Cell Surface Antigens of Anaerobic Bacteria

DTIC Science & Technology

1977-01-15

sterile cecal contents were included in all inocula, our data indicates * that cecal contents from germ free rats can be used in place of sterile cecal...The void volume of the column was estimated with blue dextran. Molecular size of the un- digested Pool 1 material was estimated using a PM-30 membrane...51) using bovine serum albumin as a standard. Total sugars were measured by the phenol-sulfuric acid method (52) using glucose as a standards

Evaluation of Composting for Reducing Volume of Solid Waste on Contingency Bases

DTIC Science & Technology

2012-05-23

Incineration Two Stage Burn Higher Burn Temperature Smaller Footprint No Sorting High Cost – Capital and Fuel Scaling and Capacity Issues...National Def nse Cent rgy and Environment Nitrogen Carbon Vapor/Gas (Void Space) Water Moisture Dry Solids Water Vapor Carbon Nitrogen Two other elements...and Environment Compost to Reduce SW on Contingency Bases, 23 May 2012, E2S2 7 National Def nse Cent rgy and Environment  The stage of the

Software Design Document for the AirNET Aeromodel and Weapons Model Conversion. Volume 1. Version 0.0,

DTIC Science & Technology

1993-01-22

AUGLPITCHROLLCONTROLa ttitude .-ontrol_roll_command, MAX..STABAUG3_PITCH-.ROLL..CONTROL); return ( attitude -.control-roll-commuand); static REAL set...pitch...if any). V V RETURNS: TRUE if successful, FALSE if not. V * PURPOSE: This routine performs the functions V V specifically related to the firing of a...specifically related to the flying a ADAT * missile. * void missile _adaLfly (aptr, sightiocation, locqsightto.world, tube, veh_list) ADATMISSILE

A Designer Fluid For Aluminum Phase Change Devices: Aluminum Inorganic Aqueous Solutions (IAS) Chemistry and Experiments. Volume 2

DTIC Science & Technology

2016-11-17

magnitude larger than necessary. Adding more permanganate into the solution can produce a thicker coating . Manganese oxide has a thermal conductivity ...void before sealing both ends. For terrestrial heat pipes, copper is the most commonly used casing material due to its high thermal conductivity ... thermal conductivity ; however, these were early results and the tubes that were obtained from the Chinese manufacturer appeared to be of inconsistent

Characteristics of solder joints under fatigue loads using piezomechanical actuation

NASA Astrophysics Data System (ADS)

Shim, Dong-Jin; Spearing, S. Mark

2003-07-01

Crack initiation and growth characteristics of solder joints under fatigue loads are investigated using piezomechanical actuation. Cracks in solder joints, which can cause failure in microelectronics components, are induced via piezoelectricity in piezo-ceramic bonded joints. Lead-zirconate-titanate ceramic plates and eutectic Sn-Pb solder bonded in a double-lap shear configuration are used in the investigation. Electric field across each piezo-ceramic plate is applied such that shear stresses/strains are induced in the solder joints. The experiments show that cracks initiate in the solder joints around defects such as voids and grow in length until they coalesce with other cracks from adjacent voids. These observations are compared with the similar thermal cycling tests from the literature to show feasibility and validity of the current method in investigating the fatigue characteristics of solder joints. In some specimens, cracks in the piezo-ceramic plates are observed, and failure in the specimens generally occurred due to piezo-ceramic plate fracture. The issues encountered in implementing this methodology such as low actuation and high processing temperatures are further discussed.

Impregnation of Composite Materials: a Numerical Study

NASA Astrophysics Data System (ADS)

Baché, Elliott; Dupleix-Couderc, Chloé; Arquis, Eric; Berdoyes, Isabelle

2017-12-01

Oxide ceramic matrix composites are currently being developed for aerospace applications such as the exhaust, where the parts are subject to moderately high temperatures (≈ 700 ∘C) and oxidation. These composite materials are normally formed by, among other steps, impregnating a ceramic fabric with a slurry of ceramic particles. This impregnation process can be complex, with voids possibly forming in the fabric depending on the process parameters and material properties. Unwanted voids or macroporosity within the fabric can decrease the mechanical properties of the parts. In order to design an efficient manufacturing process able to impregnate the fabric well, numerical simulations may be used to design the process as well as the slurry. In this context, a tool is created for modeling different processes. Thétis, which solves the Navier-Stokes-Darcy-Brinkman equation using finite volumes, is expanded to take into account capillary pressures on the mesoscale. This formulation allows for more representativity than for Darcy's law (homogeneous preform) simulations while avoiding the prohibitive simulation times of a full discretization for the composing fibers at the representative elementary volume scale. The resulting tool is first used to investigate the effect of varying the slurry parameters on impregnation evolution. Two different processes, open bath impregnation and wet lay-up, are then studied with emphasis on varying their input parameters (e.g. inlet velocity).

Heterogeneous porous structures for the fastest liquid absorption

NASA Astrophysics Data System (ADS)

Shou, Dahua; Ye, Lin; Fan, Jintu

2013-08-01

Engineered porous materials, which have fast absorption of liquids under global constraints (e.g. volume, surface area, or cost of the materials), are useful in many applications including moisture management fabrics, medical wound dressings, paper-based analytical devices, liquid molding composites, etc.. The absorption in capillary tubes and porous media is driven by the surface tension of liquid, which is inversely proportional to the pore size. On the contrary, the ability of conduction (or permeability) of liquid in porous materials is linear with the square of pore size. Both mechanisms superimpose with each other leading to a possibility of the fastest absorption for a porous structure. In this work, we explore the flow behaviors for the fastest absorption using heterogeneous porous architectures, from two-portion tubes to two-layer porous media. The absorption time for filling up the voids in these porous materials is expressed in terms of pore size, height and porosity. It is shown that under the given height and void volume, these two-component porous structures with a negative gradient of pore size/porosity against the imbibition direction, have a faster absorption rate than controlled samples with uniform pore size/porosity. Particularly, optimal structural parameters including pore size, height and porosity are found for the minimum absorption time. The obtained results will be used as a priori for the design of porous structures with excellent water absorption and moisture management property in various fields.

International Space Station Urine Monitoring System Functional Integration and Science Testing

NASA Technical Reports Server (NTRS)

Rodriquez, Branelle R.; Broyan, James Lee, Jr.

2011-01-01

Exposure to microgravity during human spaceflight needs to be better understood as the human exploration of space requires longer duration missions. It is known that long term exposure to microgravity causes bone loss. Measuring the calcium and other metabolic byproducts in a crew member s urine can evaluate the effectiveness of bone loss countermeasures. The International Space Station (ISS) Urine Monitoring System (UMS) is an automated urine collection device designed to collect urine, separate the urine and air, measure the void volume, and allow for syringe sampling. Accurate measuring and minimal cross-contamination is essential to determine bone loss and the effectiveness of countermeasures. The ISS UMS provides minimal cross-contamination (<0.7 mL urine) and has volume accuracy of 2% between 100 to 1000 mL urine voids. Designed to provide a non-invasive means to collect urine samples from crew members, the ISS UMS operates in-line with the Node 3 Waste and Hygiene Compartment (WHC). The ISS UMS has undergone modifications required to interface with the WHC, including material changes, science algorithm improvements, and software platform revisions. Integrated functional testing was performed to determine the pressure drop, air flow rate, and the maximum amount of fluid capable of being discharged from the UMS to the WHC. This paper will detail the results of the science and the functional integration tests.

Desmopressin is an Effective Treatment for Mixed Nocturia with Nocturnal Polyuria and Decreased Nocturnal Bladder Capacity

PubMed Central

Lee, Hye Won; Choo, Myung-Soo; Lee, Jeong Gu; Park, Choal Hee; Paick, Jae-Seung; Lee, Jeong Zoo; Han, Deok Hyun; Park, Won Hee

2010-01-01

To investigate the efficacy and safety of desmopressin in patients with mixed nocturia, Patients aged ≥18 yr with mixed nocturia (≥2 voids/night and a nocturnal polyuria index [NPi] >33% and a nocturnal bladder capacity index [NBCi] >1) were recruited. The optimum dose of oral desmopressin was determined during a 3-week dose-titration period and the determined dose was maintained for 4 weeks. The efficacy was assessed by the frequency-volume charts and the sleep questionnaire. The primary endpoint was the proportion of patients with a 50% or greater reduction in the number of nocturnal voids (NV) compared with baseline. Among 103 patients enrolled, 94 (79 men and 15 women) were included in the analysis. The proportion of patients with a 50% or greater reduction in NV was 68 (72%). The mean number of NV decreased significantly (3.20 to 1.34) and the mean nocturnal urine volume, nocturia index, NPi, and NBCi decreased significantly. The mean duration of sleep until the first NV was prolonged from 118.4±44.1 to 220.3±90.7 min (P<0.001). The overall impression of patients about their quality of sleep improved. Adverse events occurred in 6 patients, including one asymptomatic hyponatremia. Desmopressin is an effective and well-tolerated treatment for mixed nocturia. PMID:21165296

Desmopressin is an effective treatment for mixed nocturia with nocturnal polyuria and decreased nocturnal bladder capacity.

PubMed

Lee, Hye Won; Choo, Myung-Soo; Lee, Jeong Gu; Park, Choal Hee; Paick, Jae-Seung; Lee, Jeong Zoo; Han, Deok Hyun; Park, Won Hee; Lee, Kyu-Sung

2010-12-01

To investigate the efficacy and safety of desmopressin in patients with mixed nocturia, Patients aged ≥ 18 yr with mixed nocturia (≥ 2 voids/night and a nocturnal polyuria index [NPi] >33% and a nocturnal bladder capacity index [NBCi] >1) were recruited. The optimum dose of oral desmopressin was determined during a 3-week dose-titration period and the determined dose was maintained for 4 weeks. The efficacy was assessed by the frequency-volume charts and the sleep questionnaire. The primary endpoint was the proportion of patients with a 50% or greater reduction in the number of nocturnal voids (NV) compared with baseline. Among 103 patients enrolled, 94 (79 men and 15 women) were included in the analysis. The proportion of patients with a 50% or greater reduction in NV was 68 (72%). The mean number of NV decreased significantly (3.20 to 1.34) and the mean nocturnal urine volume, nocturia index, NPi, and NBCi decreased significantly. The mean duration of sleep until the first NV was prolonged from 118.4 ± 44.1 to 220.3 ± 90.7 min (P<0.001). The overall impression of patients about their quality of sleep improved. Adverse events occurred in 6 patients, including one asymptomatic hyponatremia. Desmopressin is an effective and well-tolerated treatment for mixed nocturia.

Effect of bipolar electric fatigue on polarization switching in lead-zirconate-titanate ceramics

NASA Astrophysics Data System (ADS)

Zhukov, Sergey; Fedosov, Sergey; Glaum, Julia; Granzow, Torsten; Genenko, Yuri A.; von Seggern, Heinz

2010-07-01

From comparison of experimental results on polarization switching in fresh and electrically fatigued lead-zirconate-titanate (PZT) over a wide range of applied fields and switching times it is concluded that fatigue alters the local field distribution inside the sample due to the generation of discrete defects, such as voids and cracks. Such defects have a strong influence on the overall electric field distribution by their shape and dielectric permittivity. On this hypothesis, a new phenomenological model of polarization switching in fatigued PZT is proposed. The model assumes that the fatigued sample can be composed of different local regions which exhibit different field strengths but otherwise can be considered as unfatigued. Consequently the temporal response of a fatigued sample is assumed to be the superposition of the field-dependent temporal responses of unfatigued samples weighted by their respective volume fraction. A certain part of the volume is excluded from the overall switching process due to the domain pinning even at earlier stages of fatigue, which can be recovered by annealing. Suitability of the proposed model is demonstrated by a good correlation between experimental and calculated data for differently fatigued samples. Plausible cause of the formation of such regions is the generation of defects such as microcracks and the change in electrical properties at imperfections such as pores or voids.

Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

DOE PAGES

Devaux, Didier; Wang, Xiaoya; Thelen, Jacob L.; ...

2016-09-08

Lithium (Li) batteries comprising multivalent positive active materials such as copper vanadium oxide have high theoretical capacity. These batteries with a conventional liquid electrolyte exhibit limited cycle life because of copper dissolution into the electrolyte. In this paper, we report here on the characterization of solid-state Li metal batteries with a positive electrode based on α-Cu 6.9V 6O 18.9 (α-CuVO 3). We replaced the liquid electrolyte by a nanostructured solid block copolymer electrolyte comprising of a mixture of polystyrene-b-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. In situ X-ray diffraction was used to follow the Li insertion/de-insertion mechanism into themore » α-CuVO 3 host material and its reversibility. In situ X-ray scattering revealed that the multistep electrochemical reactions involved are similar in the presence of liquid or solid electrolyte. The capacity fade of the solid-state batteries is less rapid than that of α-CuVO 3–Li metal batteries with a conventional liquid electrolyte. Hard X-ray microtomography revealed that upon cycling, voids and Cu-rich agglomerates were formed at the interface between the Li metal and the SEO electrolyte. Finally, the void volume and the volume occupied by the Cu-rich agglomerates were independent of C-rate and cycle number.« less

Saw palmetto for benign prostatic hyperplasia.

PubMed

Bent, Stephen; Kane, Christopher; Shinohara, Katsuto; Neuhaus, John; Hudes, Esther S; Goldberg, Harley; Avins, Andrew L

2006-02-09

Saw palmetto is used by over 2 million men in the United States for the treatment of benign prostatic hyperplasia and is commonly recommended as an alternative to drugs approved by the Food and Drug Administration. In this double-blind trial, we randomly assigned 225 men over the age of 49 years who had moderate-to-severe symptoms of benign prostatic hyperplasia to one year of treatment with saw palmetto extract (160 mg twice a day) or placebo. The primary outcome measures were changes in the scores on the American Urological Association Symptom Index (AUASI) and the maximal urinary flow rate. Secondary outcome measures included changes in prostate size, residual urinary volume after voiding, quality of life, laboratory values, and the rate of reported adverse effects. There was no significant difference between the saw palmetto and placebo groups in the change in AUASI scores (mean difference, 0.04 point; 95 percent confidence interval, -0.93 to 1.01), maximal urinary flow rate (mean difference, 0.43 ml per minute; 95 percent confidence interval, -0.52 to 1.38), prostate size, residual volume after voiding, quality of life, or serum prostate-specific antigen levels during the one-year study. The incidence of side effects was similar in the two groups. In this study, saw palmetto did not improve symptoms or objective measures of benign prostatic hyperplasia. (ClinicalTrials.gov number, NCT00037154.). Copyright 2006 Massachusetts Medical Society.

Evolution of density and velocity profiles of dark matter and dark energy in spherical voids

NASA Astrophysics Data System (ADS)

Novosyadlyj, Bohdan; Tsizh, Maksym; Kulinich, Yurij

2017-02-01

We analyse the evolution of cosmological perturbations which leads to the formation of large isolated voids in the Universe. We assume that initial perturbations are spherical and all components of the Universe (radiation, matter and dark energy) are continuous media with ideal fluid energy-momentum tensors, which interact only gravitationally. Equations of the evolution of perturbations for every component in the comoving to cosmological background reference frame are obtained from equations of energy and momentum conservation and Einstein's ones and are integrated numerically. Initial conditions are set at the early stage of evolution in the radiation-dominated epoch, when the scale of perturbation is much larger than the particle horizon. Results show how the profiles of density and velocity of matter and dark energy are formed and how they depend on parameters of dark energy and initial conditions. In particular, it is shown that final matter density and velocity amplitudes change within range ˜4-7 per cent when the value of equation-of-state parameter of dark energy w vary in the range from -0.8 to -1.2, and change within ˜1 per cent only when the value of effective sound speed of dark energy vary over all allowable range of its values.

DEM study of fabric features governing undrained post-liquefaction shear deformation of sand

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

Wang, Rui; Fu, Pengcheng; Zhang, Jian-Min

In an effort to study undrained post-liquefaction shear deformation of sand, the discrete element method (DEM) is adopted to conduct undrained cyclic biaxial compression simulations on granular assemblies consisting of 2D circular particles. The simulations are able to successfully reproduce the generation and eventual saturation of shear strain through the series of liquefaction states that the material experiences during cyclic loading after the initial liquefaction. Also, DEM simulations with different deviatoric stress amplitudes and initial mean effective stresses on samples with different void ratios and loading histories are carried out to investigate the relationship between various mechanics- or fabric-related variablesmore » and post-liquefaction shear strain development. It is found that well-known metrics such as deviatoric stress amplitude, initial mean effective stress, void ratio, contact normal fabric anisotropy intensity, and coordination number, are not adequately correlated to the observed shear strain development and, therefore, could not possibly be used for its prediction. A new fabric entity, namely the Mean Neighboring Particle Distance (MNPD), is introduced to reflect the space arrangement of particles. It is found that the MNPD has an extremely strong and definitive relationship with the post-liquefaction shear strain development, showing MNPD’s potential role as a parameter governing post-liquefaction behavior of sand.« less

DEM study of fabric features governing undrained post-liquefaction shear deformation of sand

DOE PAGES

Wang, Rui; Fu, Pengcheng; Zhang, Jian-Min; ...

2016-10-05

In an effort to study undrained post-liquefaction shear deformation of sand, the discrete element method (DEM) is adopted to conduct undrained cyclic biaxial compression simulations on granular assemblies consisting of 2D circular particles. The simulations are able to successfully reproduce the generation and eventual saturation of shear strain through the series of liquefaction states that the material experiences during cyclic loading after the initial liquefaction. Also, DEM simulations with different deviatoric stress amplitudes and initial mean effective stresses on samples with different void ratios and loading histories are carried out to investigate the relationship between various mechanics- or fabric-related variablesmore » and post-liquefaction shear strain development. It is found that well-known metrics such as deviatoric stress amplitude, initial mean effective stress, void ratio, contact normal fabric anisotropy intensity, and coordination number, are not adequately correlated to the observed shear strain development and, therefore, could not possibly be used for its prediction. A new fabric entity, namely the Mean Neighboring Particle Distance (MNPD), is introduced to reflect the space arrangement of particles. It is found that the MNPD has an extremely strong and definitive relationship with the post-liquefaction shear strain development, showing MNPD’s potential role as a parameter governing post-liquefaction behavior of sand.« less

Understanding Irreversible Degradation of Nb3Sn Wires with Fundamental Fracture Mechanics

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

Zhai, Yuhu; Calzolaio, Ciro; Senatore, Carmine

2014-08-01

Irreversible performance degradation of advanced Nb3Sn superconducting wires subjected to transverse or axial mechanical loading is a critical issue for the design of large-scale fusion and accelerator magnets such as ITER and LHC. Recent SULTAN tests indicate that most cable-in-conduit conductors for ITER coils made of Nb3Sn wires processed by various fabrication techniques show similar performance degradation under cyclic loading. The irreversible degradation due to filament fracture and local strain accumulation in Nb3Sn wires cannot be described by the existing strand scaling law. Fracture mechanic modeling combined with X-ray diffraction imaging of filament micro-crack formation inside the wires under mechanicalmore » loading may reveal exciting insights to the wire degradation mechanisms. We apply fundamental fracture mechanics with a singularity approach to study influence of wire filament microstructure of initial void size and distribution to local stress concentration and potential crack propagation. We report impact of the scale and density of the void structure on stress concentration in the composite wire materials for crack initiation. These initial defects result in an irreversible degradation of the critical current beyond certain applied stress. We also discuss options to minimize stress concentration in the design of the material microstructure for enhanced wire performance for future applications.« less

Synthesis and characterization of an injectable allograft bone/polymer composite bone void filler with tunable mechanical properties.

PubMed

Dumas, Jerald E; Zienkiewicz, Katarzyna; Tanner, Shaun A; Prieto, Edna M; Bhattacharyya, Subha; Guelcher, Scott A

2010-08-01

In recent years, considerable effort has been expended toward the development of synthetic bone graft materials. Injectable biomaterials offer several advantages relative to implants due to their ability to cure in situ, thus conforming to irregularly shaped defects. While Food and Drug Administration-approved injectable calcium phosphate cements have excellent osteoconductivity and compressive strengths, these materials have small pore sizes (e.g., 1 mum) and are thus relatively impermeable to cellular infiltration. To overcome this limitation, we aimed to develop injectable allograft bone/polyurethane (PUR) composite bone void fillers with tunable properties that support rapid cellular infiltration and remodeling. The materials comprised particulated (e.g., >100 microm) allograft bone particles and a biodegradable two-component PUR, and had variable (e.g., 30%-70%) porosities. The injectable void fillers exhibited an initial dynamic viscosity of 220 Pa.s at clinically relevant shear rates (40 s(-1)), wet compressive strengths ranging from < 1 to 13 MPa, working times from 3 to 8 min, and setting times from 10 to 20 min, which are comparable to the properties of calcium phosphate bone cements. When injected in femoral plug defects in athymic rats, the composites supported extensive cellular infiltration, allograft resorption, collagen deposition, and new bone formation at 3 weeks. The combination of both initial mechanical properties suitable for weight-bearing applications as well as the ability of the materials to undergo rapid cellular infiltration and remodeling may present potentially compelling opportunities for injectable allograft/PUR composites as biomedical devices for bone regeneration.

Long-term therapeutic efficacy of photo-selective vaporization of prostate

NASA Astrophysics Data System (ADS)

Arum, Carl-Jørgen; Muller, Camilla; Romundstad, Pal; Stokkan, Inger; Mjønes, Jan

2010-02-01

OBJECTIVES: We evaluated the long term therapeutic efficacy of 80 watt photo-selective vaporization of the prostate (PVP) in patients suffering from lower urinary tract symptoms (LUTS) secondary to prostatic obstruction. MATERIAL & METHODS: 150 unselected patients at the average age 73 (range 51-92) and a mean American Society of Anesthesiologists score of 2.4 (median 2.0), of whom 33% were medicated with acetylsalicylic acid and 5% were anticoagulated with warfarin. Inclusion/exclusion criteria were the same as for TUR-P at our institution. First patient was operated March 2004 and yearly follow-up of all patients has been attempted for 5 years. Follow-up variables have included yearly creatinine, PSA, IPSS, ØOL, post-void residual urin and maximum/average urine flow rate. RESULTS: At 12 and 24 months postoperatively, the following parameters were significantly (p<0.001) improved: trans-rectal ultrasound, international prostate symptom score, quality of life score, post-void residual urine volume, flow max/average, opening pressure, pressure @ flow-max, and micturition resistance. At 48 and 60 months creatinine, PSA, IPSS, ØOL, post-void residual urin and maximum/average urine flow rates were still significantly (p<0.001) improved compared to pre-operative values. CONCLUSION: Up to 5 year follow-up reveals that 80 watt PVP provides significant and stable symptom relief as well as objective improvement in residual urine and flowmetric outcomes.

[External sphincterotomy using bipolar vaporisation in saline. First results].

PubMed

Even, L; Guillotreau, J; Mingat, N; Castel-Lacanal, E; Braley, E; Malavaud, B; Marque, P; Rischmann, P; Gamé, X

2012-07-01

The aim of this study was to assess the feasibility, efficacy and tolerance of external urethral sphincter vaporization in saline for treating detrusor-sphincter dyssynergia. Between 2009 and 2011 a monocentric prospective study of ten men mean age 58±9 years with neurogenic detrusor-sphincter dyssynergia was carried out. Preoperative evaluation included kidney ultrasound scan, 24-hour creatinine clearance, urodynamics, retrograde and voiding urethrocystography and an at least 6 months temporary stent sphincterotomy. Postoperative assessment was composed of an ultrasound scan post-void residual volume measurement when the urethral catheter were removed and 1 year after the procedure, a retrograde and voiding urethrocystography at 3 months and a flexible cystoscopy at 1 year. At the catheter removal, eight patients emptied their bladder at completion, a supra-pubic catheter was temporary left in one case and a patient had a permanent urinary retention. For a mean follow-up of 22±11 months, eight patients emptied their bladder at completion and two had a complete urinary retention related to a detrusor underactivity. An orchitis occurred in one case 1 month after the procedure and an urethral stricture in four cases in 12.75±5.68 months on average. External urethral sphincter vaporisation saline was feasible and efficient for treating detrusor-sphincter dyssynergia but was associated with a high risk of urethral stricture. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Reliability Improvement By Adopting Ti-barrier Metal For Porous Low-k ILD Structure

NASA Astrophysics Data System (ADS)

Sakata, A.; Yamashita, S.; Omoto, S.; Hatano, M.; Wada, J.; Higashi, K.; Yamaguchi, H.; Yosho, T.; Imamizu, K.; Yamada, M.; Hasunuma, M.; Takahashi, S.; Yamada, A.; Hasegawa, T.; Motoyama, K.; Tagami, M.; Kitano, T.; Kaneko, H.

2007-10-01

Titanium (Ti) has been proposed as an excellent barrier metal (BM) material for ULSI's Cu metallization from the stand point of two characteristics. One is the oxidation property, especially for the porous low-k ILD materials for 45 nm node device; the other is the interface behavior of Ti with Cu. Both stress induced voiding (SIV) suppression and one order longer electromigration (EM) lifetime were obtained by the adoption of Ti-BM instead of the conventional Tantalum (Ta)-BM. SIV failure is accelerated in porous low-k ILD by the following steps; 1) BM oxidation by the absorbed moisture in porous low-k ILD, 2) Adhesion degradation caused by the BM oxidation results in micro delamination of Cu film (void nucleation), 3) Void growth induced by the stress gradient in the Cu interconnect. It has been considered that the small volume change of Ti oxidation and the existence of metallic Ti-O solid-solution phase would be the reason for control of moisture penetration from the low-k ILD materials. In addition, Ti/Cu intermetallic reaction and the segregation of Ti atoms at Cu grain boundaries suppress Cu migration at BM/Cu interface and Cu grain boundaries, respectively. This is supported by higher EM activation energy of Cu line with Ti-BM than that with Ta-BM. These phenomena contribute to higher interconnect reliability.

Voids and superstructures: correlations and induced large-scale velocity flows

NASA Astrophysics Data System (ADS)

Lares, Marcelo; Luparello, Heliana E.; Maldonado, Victoria; Ruiz, Andrés N.; Paz, Dante J.; Ceccarelli, Laura; Garcia Lambas, Diego

2017-09-01

The expanding complex pattern of filaments, walls and voids build the evolving cosmic web with material flowing from underdense on to high density regions. Here, we explore the dynamical behaviour of voids and galaxies in void shells relative to neighbouring overdense superstructures, using the Millenium simulation and the main galaxy catalogue in Sloan Digital Sky Survey data. We define a correlation measure to estimate the tendency of voids to be located at a given distance from a superstructure. We find voids-in-clouds (S-types) preferentially located closer to superstructures than voids-in-voids (R-types) although we obtain that voids within ˜40 h-1 Mpc of superstructures are infalling in a similar fashion independently of void type. Galaxies residing in void shells show infall towards the closest superstructure, along with the void global motion, with a differential velocity component depending on their relative position in the shell with respect to the direction to the superstructure. This effect is produced by void expansion and therefore is stronger for R-types. We also find that galaxies in void shells facing the superstructure flow towards the overdensities faster than galaxies elsewhere at the same relative distance to the superstructure. The results obtained for the simulation are also reproduced for the Sky Survey Data Release data with a linearized velocity field implementation.

Pressure effects on the structure, kinetic, and thermodynamic properties of heat-induced aggregation of protein studied by FT-IR spectroscopy

NASA Astrophysics Data System (ADS)

Taniguchi, Y.; Okuno, A.; Kato, M.

2010-03-01

Pressure can retrain the heat-induced aggregation and dissociate the heat-induced aggregates. We observed the aggregation-preventing pressure effect and the aggregates-dissociating pressure effect to characterize the heat-induced aggregation of equine serum albumin (ESA) by FT-IR spectroscopy. The results suggest the α-helical structure collapses at the beginning of heat-induced aggregation through the swollen structure, and then the rearrangement of structure to the intermolecular β-sheet takes place through partially unfolded structure. We determined the activation volume for the heat-induced aggregation (ΔV# = +93 ml/mol) and the partial molar volume difference between native state and heat-induced aggregates (ΔV=+32 ml/mol). This positive partial molar volume difference suggests that the heat-induced aggregates have larger internal voids than the native structure. Moreover, the positive volume change implies that the formation of the intermolecular β-sheet is unfavorable under high pressure.

Visualization and void-fraction measurements in a molten metal bath

NASA Astrophysics Data System (ADS)

Baker, Michael Charles

In the experimental study of multiphase flow phenomena, including intense multiphase interactions, such as vapor explosions, the fluids are often opaque. To obtain images, suitable for quantitative analysis, of such phenomena requires the use of something other than visible light, such as x-rays or neutrons. In this study a unique flow visualization technique using a continuous high energy x-ray source to measure void fraction with good spatial and temporal resolution in pools of liquid metal has been developed. In the present experiments, 11 to 21 kg of molten tin at 360sp° C to 425sp° C is collected in a pre-heated stainless steel test section of rectangular cross section (18 x 10 cm). In the base of the test section are two injection ports for the introduction of nitrogen gas and water. Each port is composed of two coaxial tubes. Nitrogen gas flows through the annular region and either nitrogen gas or water flows through the central tube. The test section is imaged using a high energy x-ray source (Varian Linatron 3000A) with a peak energy of 9 MeV and a maximum on axis dose rate of 30 Gy/min. The transmitted x-rays are viewed with an imaging system composed of a high density silicate glass screen, a mirror, a lens coupled image intensifier, and a CCD camera. Two interchangeable CCD cameras allow for either high resolution imaging (1128 x 480 pixels) at a frame rate of 30 Hz or low resolution imaging (256 x 256 pixels) at a frame rate of 220 Hz. The collected images are digitally processed to obtain the chordal averaged local and volume integral void fractions. At the experimental conditions examined, estimated relative uncertainty using this measurement technique is 10% for worst case conditions. The upper bound on the relative systematic error due to void dynamics is estimated to be 20%. Reasonable agreement has been demonstrated between the data generated from the processed images, past integral void fraction experimental data, and a semi-empirical drift-flux correlation.

Galaxy Clustering Topology in the Sloan Digital Sky Survey Main Galaxy Sample: A Test for Galaxy Formation Models

NASA Astrophysics Data System (ADS)

Choi, Yun-Young; Park, Changbom; Kim, Juhan; Gott, J. Richard, III; Weinberg, David H.; Vogeley, Michael S.; Kim, Sungsoo S.; SDSS Collaboration

2010-09-01

We measure the topology of the main galaxy distribution using the Seventh Data Release of the Sloan Digital Sky Survey, examining the dependence of galaxy clustering topology on galaxy properties. The observational results are used to test galaxy formation models. A volume-limited sample defined by Mr < -20.19 enables us to measure the genus curve with an amplitude of G = 378 at 6 h -1 Mpc smoothing scale, with 4.8% uncertainty including all systematics and cosmic variance. The clustering topology over the smoothing length interval from 6 to 10 h -1 Mpc reveals a mild scale dependence for the shift (Δν) and void abundance (AV ) parameters of the genus curve. We find substantial bias in the topology of galaxy clustering with respect to the predicted topology of the matter distribution, which varies with luminosity, morphology, color, and the smoothing scale of the density field. The distribution of relatively brighter galaxies shows a greater prevalence of isolated clusters and more percolated voids. Even though early (late)-type galaxies show topology similar to that of red (blue) galaxies, the morphology dependence of topology is not identical to the color dependence. In particular, the void abundance parameter AV depends on morphology more strongly than on color. We test five galaxy assignment schemes applied to cosmological N-body simulations of a ΛCDM universe to generate mock galaxies: the halo-galaxy one-to-one correspondence model, the halo occupation distribution model, and three implementations of semi-analytic models (SAMs). None of the models reproduces all aspects of the observed clustering topology; the deviations vary from one model to another but include statistically significant discrepancies in the abundance of isolated voids or isolated clusters and the amplitude and overall shift of the genus curve. SAM predictions of the topology color dependence are usually correct in sign but incorrect in magnitude. Our topology tests indicate that, in these models, voids should be emptier and more connected and the threshold for galaxy formation should be at lower densities.

ICPP tank farm closure study. Volume 2: Engineering design files

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

NONE

1998-02-01

Volume 2 contains the following topical sections: Tank farm heel flushing/pH adjustment; Grouting experiments for immobilization of tank farm heel; Savannah River high level waste tank 20 closure; Tank farm closure information; Clean closure of tank farm; Remediation issues; Remote demolition techniques; Decision concerning EIS for debris treatment facility; CERCLA/RCRA issues; Area of contamination determination; Containment building of debris treatment facility; Double containment issues; Characterization costs; Packaging and disposal options for the waste resulting from the total removal of the tank farm; Take-off calculations for the total removal of soils and structures at the tank farm; Vessel off-gas systems; Jet-groutedmore » polymer and subsurface walls; Exposure calculations for total removal of tank farm; Recommended instrumentation during retrieval operations; High level waste tank concrete encasement evaluation; Recommended heavy equipment and sizing equipment for total removal activities; Tank buoyancy constraints; Grout and concrete formulas for tank heel solidification; Tank heel pH requirements; Tank cooling water; Evaluation of conservatism of vehicle loading on vaults; Typical vault dimensions and approximately tank and vault void volumes; Radiological concerns for temporary vessel off-gas system; Flushing calculations for tank heels; Grout lift depth analysis; Decontamination solution for waste transfer piping; Grout lift determination for filling tank and vault voids; sprung structure vendor data; Grout flow properties through a 2--4 inch pipe; Tank farm load limitations; NRC low level waste grout; Project data sheet calculations; Dose rates for tank farm closure tasks; Exposure and shielding calculations for grout lines; TFF radionuclide release rates; Documentation of the clean closure of a system with listed waste discharge; and Documentation of the ORNL method of radionuclide concentrations in tanks.« less