Large scale space diversity in a widely spaced network of meteorscatter communication systems and its application to mobilecommunications

A model is developed for predicting the inherent spatial multiplexing or diversity in a widely dispersed network of meteor scatter receivers. The primary measure, network diversity, is defined as the ratio of the arrival rate of useful trails observed by the entire network to the arrival rate at an average node and is less than the number of receivers in the network. Network diversity is calculated from the ground illumination footprint of individual meteor trails and weighted by the spatial arrival pattern of trails. Predictions using the model are compared to an experiment conducted in the western US. Ramifications on the design of meteor scatter communication systems for very large network applications such as automatic vehicle location and tracking are discussed     

Pilot Study for the Performance of a New Demand Control Ventilation System in Hong Kong

There are different ventilation control methods for outdoor air quantity in air-conditioned spaces to reduce the energy consumed in cooling the outdoor air. Demand controlled ventilation (DCV) is an important strategy to control the outdoor air quantity. However, the current practice in DCV systems creates several problems for air-conditioned office buildings. Although metabolic carbon dioxide (CO2) concentration is mainly used as a surrogate indicator for ventilation adequacy, the conventional DCV system does not seriously consider the placement location of the CO2 sensor, and it does not take into account the adverse effects of the consequential increase in pollutant concentrations in the indoor space when the fresh airflow rate is reduced. In this study, a long period of subjective and objective measurements were conducted in an occupied office to examine its suitability for conversion to a new demand controlled ventilation system (nDCV). After the feasibility investigation, an nDCV system was developed to optimize the energy consumed for outdoor air ventilation while providing the desirable thermal comfort and indoor air quality. The true optimization of this nDCV is achieved by a new concept of the optimized indoor air quality window which determines the most representative locations for the indicator sensors. A minimum ventilation rate is determined by a calibration procedure for the pollutant inventory of a building, taking into account the infiltration characteristics. Radon gas, which is a notorious carcinogenic indoor pollutant, is used as a reference to determine the minimum fresh airflow rate. The findings show that this nDCV system reduced 16% of fresh air cooling energy consumption without jeopardizing the thermal comfort and indoor air quality.     

Preliminary Characterization of Novel Extra-cellular Lipase from Penicillium crustosum Under Solid-State Fermentation and its Potential Application for Triglycerides Hydrolysis

Current studies about lipase production involve the use of agro-industrial residues and newly isolated microorganisms aimed at increasing economic attractiveness of the process. Based on these aspects, the main objective of this work is to perform the partial characterization of enzymatic extracts produced by a newly isolated Penicillium crustosum in solid-state fermentation. Lipase extract presented optimal temperature and pH of 37?°C and 9?C10, respectively. The concentrated enzymatic extract showed more stability at 25?°C and pH?7. The enzymes kept 100% of their enzymatic activity until 60?days of storage at 4 and ?10?°C. The stability under calcium salts indicated that the hydrolytic activity presented decay with the increase of calcium concentration. The specificity under several substrates indicated good enzyme activities in triglycerides from C4 to C18.     

Adapting technology: effect of high-involvement HRM and organisational trust

This study is designed to empirically test a model of high-involvement human resource management (HIHRM), organisational trust, and technology adaptation grounded on social exchange theory in the context of the private banking sector. The proposed model intends to add to the understanding of the effect of HIHRM on technology adaptation via the mediating influence of organisational trust. Frontline employees were surveyed using a self-administered questionnaire. Results from partial least square-structural equation modelling suggest that there is a significant influence of HIHRM on technology adaptation. Organisational trust further mediates the relationship. Thus, this paper finds an answer to the ‘black box’ of human resource management (HRM) practices, explaining how HIHRM influences employees’ attitudes towards technology adaptation. The study can help management have a better understanding of the importance of employee involvement-oriented HRM in introducing and implementing a new technology through the integration of trust processes in the organisation.     

Berechnung von dreidimensionalen elektromagnetischen Feldern bei der induktiven Erwärmung

Übersicht Es wird ein numerisches 3D-Berechnungsverfahren vorgestellt, mit dem die elektromagnetischen (EM-) Felder bei induktiver Hochfrequenz-(HF-) oder Banderwärmung, also im Fall dünner stromführender Schichten, simuliert werden. Darüber hinaus lassen sich Leistungs- und Kraftverteilungen sowie integrale Größen, wie z. B. Impedanz, Spannung und Wirkleistung, ermitteln. Für das Berechnungsprogramm werden die prozeßrelevanten Teile der betrachteten Anlagen entsprechend ihrer elektromagnetischen Eigenschaften bestimmten Gruppen zugeordnet. Für jede Gruppe gelten spezifische Randbedingungen an der Oberfläche bezüglich der EM-Felder. Das Berechnungsprogramm basiert auf der Boundary-Element-Methode (BEM) und berücksichtigt die anlagenspezifischen Symmetrien, so daß Rechner genutzt werden können, die in Forschung und Entwicklung heute allgemein zugänglich sind (PC, Workstation). Am Beispiel zweier Anwendungsfälle wird die Leistungsfähigkeit des entwickelten Programmpaketes aufgezeigt.

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Calculation of threedimensional electromagnetic fields during induction heating

Contents A numerical 3D-calculation method for the simulation of the electromagnetic field during high frequency induction heating or induction strip heating, i.e. in case of thin current-carrying layers, is presented. In addition, the described programme allows to calculate the distributions of power and force as well as integral quantities, for example the impedance, the voltage and the active power. The parts of the setup to be considered are assigned to certain groups according to their electromagnetic properties. Each group has its specific boundary conditions at the surface describing the electromagnetic field. The calculation program uses the boundary element method and takes into account the set-up specific symmetries. Therefore the program runs on computers (PC, Workstations), which are widely available for research and development purposes nowadays. Finally, two examples basing on industrial applications show the efficiency of the developed program.

     

Towards tuning of surface properties by atomic and molecular adsorption on boron-terminated cubic boron nitride (111) surface: A first-principles study

We present a theoretical investigation for the adsorptions of triangular nitrogen trimer radical (N₃) at both the hollow (H3) and fourfold coordinated top (T4) sites on boron-terminated (111) (B(111)) surface of cubic boron nitride (c-BN) in terms of structure, adsorption energy, band structure and work function. For the first time, we explore the H3 and T4 adsorption mechanisms. Moreover, we study the subsequent co-adsorption of N₃, boron and hydrogen atoms on the same adsorption site on the B(111) surface, which will form either pyramid quantum cluster or nearly planar adsorbate. We find that the surface band structure varies substantially depending on the types of terminated surface formed (changing from metallic to semi-conducting), and consequently, the surface work function changes. These results indicate the electronic characteristics of the B(111) surface can be tuned readily using chemical co-adsorption, suggesting its potential for chemical sensing applications.     

IL-10 inhibits macrophage activation and proliferation by distinct signaling mechanisms: evidence for Stat3-dependent and -independent pathways

Interleukin-10 (IL-10) limits inflammatory responses by inhibiting macrophage activation. In macrophages, IL-10 activates Stat1 and Stat3. We characterized IL-10 responses of the J774 mouse macrophage cell line, and of J774 cells expressing wild-type hIL-10R, mutant hIL-10R lacking two membrane-distal tyrosines involved in recruitment of Stat3 (hIL-10R-TyrFF), a truncated Stat3 (DeltaStat3) which acts as a dominant negative, or an inducibly active Stat3-gyraseB chimera (Stat3-GyrB). A neutralizing anti-mIL-10R monoclonal antibody was generated to block the function of endogenous mIL-10R. IL-10 inhibited proliferation of J774 cells and of normal bone marrow-derived macrophages, but not J774 cells expressing hIL-10RTyrFF. Dimerization of Stat3-GyrB by coumermycin mimicked the effect of IL-10, and expression of DeltaStat3 blocked the anti-proliferative activity of IL-10. For macrophage de-activation responses, hIL10R-TyrFF could not mediate inhibition of lipopolysaccharide-induced TNFalpha, IL-1beta or CD86 expression, while DeltaStat3 did not interfere detectably with these IL-10 responses. Thus signals mediating both anti-proliferative and macrophage de-activation responses to IL-10 require the two membrane-distal tyrosines of IL-10R, but Stat3 appears to function only in the anti-proliferative response.     

Depression among elderly Chinese immigrants: an exploratory study

Despite an increase in the population of elderly Chinese immigrants, little is known about their mental health problems. The most prevalent mental health problem of elderly people-depression-often goes unrecognized and untreated. In an interview format, the author administered the Geriatric Depression Scale and measures of health status, living situation, stressful life events, and informal support to a community sample of 50 elderly Chinese immigrants recruited at senior centers and meal sites. Respondents who rated their health as good, who lived with others, and who were satisfied with help received from family members were least likely to be depressed. The impact of these factors on the mental health of elderly Chinese immigrants can be understood in light of their unique cultural values.     

Properties of Si/sub 3/N/sub 4//Si/sub x/Ge/sub 1-x/ metal-insulator-semiconductor capacitors

The density of fast interface states was studied in Si/sub 3/N/sub 4//Si/sub 0.8/Ge/sub 0.2/ metal-insulator-semiconductor (MIS) capacitors. The interface state density does not appear to be strongly affected by the presence of a thin Si interlayer between the nitride and SiGe alloy. This is in contrast to the results when SiO/sub 2/ is used as the insulator material in similar structures.<>