An oxygen electrode for air-consuming proton exchange membrane fuel cells for transportation applications

Electrodes for air-driven PEMFCs for transport applications have been developed. The structure of the electrodes has been specifically adapted to run with air as oxidant under near atmospheric pressure; such electrodes can be manufactured using conventional industrial methods and be easily scaled up. The technology has been demonstrated on a 50 cm² electrode area, assembled together with a Nafion® 117 membrane. Electrodes with different platinum loading, namely 0.4 and 0.2 mg Pt cm^–2, have been the subject of long duration tests which show a slow degradation of the cell performance. With air as oxidant at 180 kPa absolute pressure, 80°C as cell temperature and Nafion® 117 as membrane, a power density of 350 mW cm^–2 has been obtained.     

Improvement of Crystallinity of KZr2P3O12 by Sol-Gel Synthesis

The X-ray diffraction pattern for potassium-zirconium phosphate is significantly improved when the material is prepared by the sol-gel route rather than the powder method. Peaks at high, low, and intermediate angles are presented and compared for the two methods. It is assumed that the more nearly homogeneous mixing of the elements in the sol-gel process is responsible for the significant improvement in crystallinity.     

Open annotations on multimedia Web resources

Many Web portals allow users to associate additional information with existing multimedia resources such as images, audio, and video. However, these portals are usually closed systems and user-generated annotations are almost always kept locked up and remain inaccessible to the Web of Data. We believe that an important step to take is the integration of multimedia annotations and the Linked Data principles. We present the current state of the Open Annotation Model, explain our design rationale, and describe how the model can represent user annotations on multimedia Web resources. Applying this model in Web portals and devices, which support user annotations, should allow clients to easily publish and consume, thus exchange annotations on multimedia Web resources via common Web standards.     

Struktur und eigenschaften von ABS-polymeren. IX. Quantitative untersuchungen zur morphologie von ABS-polymerisaten

The technological properties of ABS polymers largely depend on the structure of the elastomer phase as well as on the elastomer/thermoplast interface. The morphological structure of such polymers can be determined from electron micrographs of ultramicrotome sections – after selective contrasting of the polybutadiene phase – or of replicas of fracture surfaces after selective chemical degradation. The various ABS polymers are classified by their manufacturing processes and their morphologies and characterized by electron micrographs. The degree and place of grafting are of particular importance. The quantitative determination of the surface- and internal grafting is achieved by combining the determination of the degree of grafting (extraction), the evaluation of the results obtained on particle counting, and a morphometric process. It is demonstrated that the morphometric process can in general be applied for the quantitative determination of the contrastable component in two-phase polymers.     

Lifetime assessment of epoxies by the kinetics of thermal degradation

The kinetics of thermal degradation of 4,4′‐diaminodiphenylsulfone (DDS)‐cured glycidylethers (DGBA) and glycidylamines (TGDDM) have been studied by isothermal annealing. Thermal degradation proceeds via first‐order kinetics with activation energies of 138 (DGBA/DDS) and 95 kJ/mol (TGDDM/DDS). From these data the temperature‐dependent lifetime can be calculated. Based on the heat distortion temperature and 20 years' service as criteria, the upper service temperature is found to be around 115–120°C. In spite of the different activation energies and bond stabilities, only marginal differences in the upper allowed service temperatures between these resins were found. Only slight improvements can be expected by optimizing the cure conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1881–1886, 2004     

Organolithium route to poly(arylsilane)s

Various poly(arylsilane)s The poly(carbosilane)s prepared in this way are of higher molecular weight than when prepared by the Wurtz-type condensation route previously reported. TG shows 40–50% overll weight loss attained at 500–600°C.     

β-Carotene transport in human lipoproteins. Comparisons with a-tocopherol

The purpose of this study was to investigate the temporal relationships of the transport of β-carotene in human lipoproteins. We administered 60 mg β-carotene with breakfast to nine fasting subjects, then blood samples were collected at intervals of up to 75 h, lipoproteins were isolated, and β-carotene was quantitated. β-Carotene concentrations in chylomicrons and very low density lipoproteins (VLDL) peaked at 6 and 9 h, respectively. Nonetheless, at all time points the majority of plasma β-carotene was contained in low density lipoproteins (LDL), while high density lipoproteins (HDL) carried a smaller portion (at 24 h, 73±8% in LDL as compared with 23±5% in HDL). In three subjects, transport of β-carotene was compred with the results of earlier studies on the transport of stereoisomers of α-tocopherol. Unlike plasmaRRR-α-tocopherol concentrations, which are maintained by the preferential incorporation ofRRR-α-tocopherol into VLDL by the liver, β-carotene increased and decreased in VLDL similarly toSRR-α-tocopherol, a stereoisomer whose concentrations are not maintained in plasma. In conclusion, β-carotene is primarily transported in the plasma in LDL, but its incorporation by the liver into lipoproteins does not appear to be enhanced.     

Gewinnung von Brennstoff für Kraftwerke aus Klärschlamm

Production of a combustible for coal-fired power stations based on sewage sludge . This article describes various means of achieving more extensive mechanical dewatering of sewage sludges. The heat content of the sludge solids can become available for combustion processes. The sludge filter cakes obtained by the “CarboSed” process can be disposed of with minimum energy consumption by fluidized bed combustion or be used after appropriate work-up as a combustible in coal-fired power stations with full exploitation of their heat content for generation of steam and electric current. Partial substitution of primary energy sources such as coal and fuel oil by sludge filter cake is feasible in all cases. The processes thus make a contribution to the saving of energy resources and the disposal of sludge.     

On the detection of custom memory allocators in C binaries

Many reverse engineering techniques for data structures rely on the knowledge of memory allocation routines. Typically, they interpose on the system’s malloc and free functions, and track each chunk of memory thus allocated as a data structure. However, many performance-critical applications implement their own custom memory allocators. Examples include webservers, database management systems, and compilers like gcc and clang. As a result, current binary analysis techniques for tracking data structures fail on such binaries. We present MemBrush, a new tool to detect memory allocation and deallocation functions in stripped binaries with high accuracy. We evaluated the technique on a large number of real world applications that use custom memory allocators. We demonstrate that MemBrush can detect allocators/deallocators with a high accuracy which is 52 out of 59 for allocators, and 29 out of 31 for deallocators in SPECINT 2006. As we show, we can furnish existing reverse engineering tools with detailed information about the memory management API, and as a result perform an analysis of the actual application specific data structures designed by the programmer. Our system uses dynamic analysis and detects memory allocation and deallocation routines by searching for functions that comply with a set of generic characteristics of allocators and deallocators.