Characterization process to measure the electrical contact resistance of Gas Diffusion Layers under mechanical static compressive loads

Recent research has identified the mechanical properties of the fuel cell internal components (in particular, the Gas Diffusion Layers – GDLs) as key-parameters to obtain high final performances of the generator. The mechanical compression modulus of these components, the stability of their mechanical properties with respect to temperature and humidity, and their ability to interact with water have an impact on the electrical contact resistances in the stack and, by consequence, on the overall performance of the electric generator. Reducing the losses by contact resistance is an objective necessary to optimize the fuel cells in operation. The study of GDL electrical behavior under various internal operating conditions provides a suitable database to better understand their effects on the overall stack performance.This paper describes an experimental method for measuring the electrical contact resistance versus the static mechanical pressure applied to the GDLs. A nonlinear behavior of the electrical contact resistance versus the mechanical stress is observed. The PTFE and MPL additions modify the electrical contact resistance.     

Hemodynamic effects of the implantation of an intracaval oxygenator

Treatment of severe respiratory failure by extracorporeal membrane oxygenation (ECMO) is complex. However, there is now an intravascular gas exchanger (IVOX) available that provides extrapulmonary gas transfer without requiring an extracorporeal blood path. The present study was performed to determine the hemodynamic effects resulting from the intracaval placement of the intravascular device. A bovine model (n = 6; body-weight = 72 +/- 5 kg) was selected for temporary lung support with the intravascular device. The latter was placed in the caval axis under fluoroscopic control after full instrumentation of the animal for hemodynamic measurements including a pulmonary artery catheter for determination of cardiac output by thermodilution and continuous readout of mixed venous oxygen saturation. All measurements were taken after a stabilization period of 15 min. The heart rate moved from 65 +/- 8 before to 72 +/- 10 after implantation and 68 +/- 9 after onset of intravascular gas exchange (NS). Right atrial pressure was 13 +/- 3 mm Hg before, 12 +/- 3 mm Hg after implantation and 10 +/- 3 mm Hg after onset (NS) whereas femoral venous pressure moved from 14 +/- 3 mm Hg to 17 +/- 4 mm Hg (p < 0.05) and remained at 17 +/- 4 mm Hg after onset. Cardiac output was 5.3 +/- 0.7 l/min before, 5.4 +/- 0.7 l/min after implantation and 5.3 +/- 1.1 l/min after onset (NS) while mixed venous oxygen saturation dropped from 60 +/- 7% to 54 +/- 11% and moved to 57 +/- 11 after onset of the device (NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy for development of the Philippines

Set against an expanding population and a rapidly developing agro-industrial economy, the Philippines demand for energy is forecast to grow at 7.5% annual rate in the next 25 years. At this pace, primary energy requirements towards the close of the century would have been 465 million barrels of oil equivalent, representing a six-fold increase over present consumption levels. Consonant with the state's self-reliant posture with respect to its energy supplies, this demand will have to be met as much as possible by indigenous sources. Accordingly, the Energy Plan outlined to the year 2000 targets the development and utilization of indigenous energy resources, particularly those which are of renewable and inexhaustible nature.The Energy Plan is based largely on assessed resource potentials of the country. With increased supply contributions from hydro, coal, nuclear, geothermal and other non-conventional sources of energy, the Plan envisions the reduction of Philippine oil dependency rate from the prevailing 95% to 72% in 1985 and 53% in 2000.Estimates of financial requirement to implement the plan indicates that for the next 10 years up to 1985, a total of US$5.4 B is needed. This corresponds to an average yearly requirement of US$520 M and is equivalent to 2.5% of average annual GNP. From 1985 to 2000, a total of US$19.7 B will be needed, or an annual requirement of US$1.3 B. This again takes up 2.5% of GNP. The physical and financial targets including the institutional framework of such a plan constitute the topics of discussion of this paper.     

Culture prior to transplantation preserves the ultrastructural integrity of monkey pancreatic islets

Transplantation of pancreatic islets represents a promising way of curing type I diabetes (insulin-dependent diabetes mellitus). Culture enables the survival of endocrine tissue awaiting islet transplantation and reduces islet immunogenicity prior to xenografting. In this study, attempts were made to preserve the monkey islets in culture for 7 days and to study the ultrastructure by electron microscopy. The islets were isolated from monkey pancreas by the collagenase digestion method and were separated from acinar cells by dextran density gradient centrifugation. These islets were preserved in a humidified atmosphere of 5% carbon dioxide and 95% air for 7 days. The culture medium used was CMRL-1066. After 7 days of culture the islets were processed for light and electron microscopic studies, which revealed that the cultured islets were intact and maintained their structural integrity. Semi-thin sections of the cultured islets showed morphology with occasional structural alterations at the periphery. Dithizone staining of the cultured islets showed crimson red colour, proving that the islets were pure and without any exocrine contamination. Electron microscopy showed that the cultured islets had well-preserved alpha-, beta- and delta-cells. Different cell types of the monkey pancreatic islets were identified by the presence of their characteristic secretory granules. The ultrastructural characteristics present in hormone-synthesizing cells, i.e. rough-endoplasmic reticulum, Golgi apparatus, mitochondria and secretory granules, were observed as in native islets.     

A Robust Algorithm for Contact Angle and Interface Detection of Water and Argon Droplets

ABSTRACT

Contact angle estimation of a liquid droplet on a solid surface is of great importance to understand its wetting properties, capillarity, and surface interaction energy. While studying the droplet on a surface using molecular dynamics (MD) simulations, the main challenge lies in separating the liquid and vapor phases, and estimating the interface, curvature, and contact angle. Further, during transient MD simulations, large amount of data processing is required for calculating the time evolution of contact angle. This is a tedious effort to do manually or with image processing algorithms and can affect the contact angle results. In this work we propose an improved version of contact angle estimation algorithm. This algorithm segregates the droplet molecules from the vapor molecules using Mahalanobis distance technique, following which the density is smeared onto a 2D grid using various interpolation functions. The smearing is done by rotating the droplet multiple times at different angles to attain more interfacial data points. The liquid-vapor interface data is estimated from the grid using density filtering. With the interface data, a circle is accurately fitted using Landau method. The equation of this circle is solved for obtaining the contact angle. We apply this algorithm to study the hydrophilic and hydrophobic contact angles for argon and water droplets on a platinum surface with varying interaction potential parameters leading to different wettability conditions, as well as contact angle evolution of water droplet on platinum surface.     

Interleukin-35 Prevents Development of Autoimmune Diabetes Possibly by Maintaining the Phenotype of Regulatory B Cells

The anti-inflammatory role of regulatory B cells (Breg cells) has been associated with IL-35 based on studies of experimental autoimmune uveitis and encephalitis. The role of Breg cells and IL-35⁺ Breg cells for type 1 diabetes (T1D) remains to be investigated. We studied PBMCs from T1D subjects and healthy controls (HC) and found lowered proportions of Breg cells and IL-35⁺ Breg cells in T1D. To elucidate the role of Breg cells, the lymphoid organs of two mouse models of T1D were examined. Lower proportions of Breg cells and IL-35⁺ Breg cells were found in the animal models of T1D compared with control mice. In addition, the systemic administration of recombinant mouse IL-35 prevented hyperglycemia after multiple low dose streptozotocin (MLDSTZ) injections and increased the proportions of Breg cells and IL-35⁺ Breg cells. A higher proportion of IFN-γ⁺ cells among Breg cells were found in the PBMCs of the T1D subjects. In the MLDSTZ mice, IL-35 administration decreased the proportions of IFN-γ⁺ cells among the Breg cells. Our data illustrate that Breg cells may play an important role in the development of T1D and that IL-35 treatment prevents the development of hyperglycemia by maintaining the phenotype of the Breg cells under an experimental T1D condition.     

Correlation between the rheological and technological properties of biscuits with different levels of replacement of wheat flour by rice and azuki bean flour

A mixture design was used to evaluate the effect of replacing (0 to 100%) wheat flour (WF) with wholegrain azuki bean (WABF) and rice (RF) flours on the biscuits quality. High proportions of WABF increased diameter and decreased thickness, whereas WF affected inversely and RF intermediate. The WF biscuit specific volume was 17% greater than that of the dough, and the WABF and RF biscuits were 5 and 13% smaller, respectively. The WABF biscuit hardness was 26.25 N, close to WF (28.14 N), and higher than RF (7.6 N). The WABF increased the colour difference (ΔE) values for biscuits by up to 22.19 and the RF by 1.87. Peak viscosity, breakdown and setback of mixture flours showed positive correlations with the dough hardness and L*, a*, b* and Aw of biscuits and negatively with the radial expansion index and ΔE. The highest global desirability was for biscuits without WF, regardless of crust colour.     

Properties of C/C-SiC composites produced via transfer moulding and inner siliconization

Short carbon fiber reinforced polymers (CFRP) are successfully prepared by transfer moulding technology. For this purpose, compounds on the basis of novolac/urotropin with different 6 mm chopped carbon fibers and silicon powder contents are produced utilizing a laboratory tempered sigma-blade kneader. These compounds are then shaped into 46 × 8 × 3 mm³ CFRP specimens using a transfer moulding machine. Depending on the material composition, the conversion to C/C-SiC composites is performed through liquid silicon infiltration (LSI) process or inner siliconization. First, the short fiber content is varied between 30 and 50 wt% and its influence on the process and properties of the composites is studied. Second, an investigation of the inner siliconization through the co-mixing of silicon powder (1-23 wt% in CFRPs) during the compound production as well as a comparison with the external silicon infiltration process are presented and discussed. According to the results, the best mechanical properties are achieved at a fiber content of 40 wt% in the case of the external silicon infiltration and at silicon content below 14 wt% for composites produced by the inner siliconization process.     

Automatic semantic edge labeling over legal citation graphs

A large number of cross-references to various bodies of text are used in legal texts, each serving a different purpose. It is often necessary for authorities and companies to look into certain types of these citations. Yet, there is a lack of automatic tools to aid in this process. Recently, citation graphs have been used to improve the intelligibility of complex rule frameworks. We propose an algorithm that builds the citation graph from a document and automatically labels each edge according to its purpose. Our method uses the citing text only and thus works only on citations who’s purpose can be uniquely identified by their surrounding text. This framework is then applied to the US code. This paper includes defining and evaluating a standard gold set of labels that cover a vast majority of citation types which appear in the “US Code” but are still short enough for practical use. We also proposed a novel linear-chain conditional random field model that extracts the features required for labeling the citations from the surrounding text. We then analyzed the effectiveness of different clustering methods such as K-means and support vector machine to automatically label each citation with the corresponding label. Besides this, we talk about the practical difficulties of this task and give a comparison of human accuracy compared to our end-to-end algorithm.