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The purpose of this paper is to assess the reliability of thermoelectric generators after ageing at elevated temperature and to determine the influence of the technology used (i.e. type of thermoelectric material, type of substrate and soldering technology) for thermogenerator (TGE) assembly.

In this paper, the Seebeck coefficient and the current voltage were measured for lead telluride doped with either manganese (PMT), germanium (PGT) or sulfur (PST) TGEs. The Seebeck coefficient measurements were taken at temperatures between 230 and 630 K.

The Seebeck coefficient determined for PMT, PGT and PST TGEs increases approximately linearly with increasing temperature and is greater by about 40 per cent for PST and about 30 per cent for PMT than in commercially available PbTe TGEs. The best outcome in terms of stability after long-term ageing was that of PMT material.

The choice of proper technology (i.e. thermoelectric materials, type of substrate and soldering technology) for the TGE assembly is essential for their functioning overtime and reliability.

Looks at the use of infrared sensors, noting that they fall into the two basic groups of quantum and thermal devices. Focuses on quantum devices and their further subdivision into photoconductive and photovoltaic types. Notes that thermal devices also fall into two categories: those relying on the Seebeck effect, and those known as ferroelectrics. Looks at the use of ferroelectric materials in pyrometry. Concludes by noting the advantages of some of the various types of system.

Modern semiconductor physics has developed from the quantum mechanical work on energy band theory of charge carriers in semiconductors associated with the name of A. H. Wilson and his classic papers on the subject, and also with the name of Schottky who pioneered the atomistic approach to disorder phenomena in solids. This work dates from about 1930 and theoretical developments up to the beginning of the War were relatively slow. Semiconductor technology in the same period was represented by a few devices only. These included the copper oxide and selenium rectifiers which were in use in certain equipment and in the process of further development. The silicon whisker detector was being used for the detection and measurement of microwave power. It will be recalled that silicon carbide and galena had been used as detectors of radio waves before the common usage of the thermionic valve. The development of radar during the War, which required semiconductor devices for detecting and mixing microwaves meant that considerable work was carried out on silicon, and parallel work on germanium meant that by the end of the War high‐back voltage rectifiers, using germanium, were available in developmental quantities. Problems of thermal detection meant that photo‐conductive and photo‐voltaic cells were developed for this purpose based on the materials thallium sulphide and lead sulphide. Attention was also focussed on electronic processes in ionic crystals in terms of improving display screens for cathode ray and similar tubes.

In this paper we build upon previous research that examines how workers in devalued occupations transform structural conditions that threaten their dignity into resources with which to protect themselves. Through in-depth interviews and fieldwork with early childhood educators (ECE), we examine the work experiences of teachers in four distinct work contexts: daycare centers and within elementary schools, each in either the public or private sector. We find that these different school organizational contexts shape what kinds of identity challenges early childhood teachers experience. Different organizational contexts not only subject teachers to different threats to their work-related identity but also have different potential identity resources embedded within them that teachers can use on their own behalf. Thus, while all the early childhood educators in our sample struggle with being employed within a devalued occupation, the identity strategies they have developed to protect their self-worth vary across employment contexts. We show that the strategies these interactive service workers use to solve identity-related problems of dignity at work involve the creative conversion of constraints they face at work into resources that help them achieve valued work identities.

The present stage of development of vehicles for space exploration corresponds to some degree to that of the aeroplane in 1905. The programme of the U.S. National Aeronautics and Space Administration in the fields of space science research, applications of Earth satellites, manned exploration of space, and vehicle development are reviewed. International co‐operation in space exploration is desirable, particularly as regards exchange of information, exchanges of scientists, co‐ordination of national programmes, and institution of co‐operative programmes.

Even though copper–tungsten has shown signs of potentials, relatively little is currently known about its appropriateness for photovoltaic application. This paper aims to evaluate the suitability of copper-tungs oxides as photovoltaic absorbers while investigating the consequences of oxygen content variation.

Using profilometry, Hall measurements, Seebeck test and spectrophotometry, grown samples were defined. Samples of 5 standard cubic centimeters per minute (sccm) and 7 sccm exhibited appropriate characteristics and were further tested using personal computer one dimension (PC1D) computational simulation at the system stage. To grow materials with an average thickness below 0.45 µm, magnetron co-sputtering was used. Three sample sets, varied by oxygen flow rate, were made with flow rates of 5sccm, 7sccm and 9sccm, respectively.

Some samples proved to be effective absorbers, using a cadmium telluride device as the criterion of output calculation, with one sample chosen as ideal for each type of flow rate. For the chosen samples, an optimum thickness was also obtained, i. It was discovered that thinner cells, optimal for both groups with 0.6 µm, performed better to than other thicknesses.

The material also demonstrated prospects for applications in window layers, but more needs to be known.

Thin film material properties and their operating processes are relatively complex, so it is important to find simple and cost-effective ways to forecast performance. While relatively new, numerical modeling has proven to be very useful in defining the critical properties of thin film devices, thereby helpful for predictions of performance. Solar cell capacitance simulator one dimension, amorphous semiconductor analysis, personal computer one dimension (PC1D), analysis of micro-electronic and photonic structures and automat for simulation for heterostructures (33) are several common models in the thin film industry. Due to its availability and relative ease of use, PC1D was used in this project.

As the search for the balance among performance, cost, reliability and availability continue, more absorber components continue to evolve, notably from the chalcogenides. Because of their ability to absorb light, ternary transition metal chalcogenides are useful in the production of hydrogen and in the energy storage sector, as well as in the production of light-emitting diodes and solar photovoltaic (PV).

There are several methods for the manufacture of copper–tungsten alloys, but the process of combinatorial sputtering of magnetrons provides satisfactory results even for the manufacture of various other materials. Cu₂WSe₄, an excellent alternative to sputtering, is one of the very few copper–tungsten selenide materials tested, synthesized by hot simple injection to have strong crystallinity and lacks impurity. The optical properties of colloidal Cu₂WSe₄ show that Schottky diode–like behaviors are present in the material, suggesting its potential for use in solar cells. Cu-W alloys could have a lot more to give the PV industry, by all indications. Further exploration of the oxides by this work is thus justified. Transparent conducting oxides, interfacial layers or charge-transporting compounds are commonly used as transition metal oxides. Nevertheless, as absorbers, metal oxides such as BiFeO₃ and the traditionally highly studied Cu₂O have been tested, with Cu₂O showing a conversion efficiency of up to 10% under particular conditions. This displays strong electronic and optical properties, so there might be some possibility of studying other PV absorption metal oxides. The optical properties of colloidal Cu₂WSe₄ show that Schottky diode–like behaviors are present in the material, suggesting its potential for use in solar cells.

The purpose of this paper is to study the effect of individual layers of cadmium telluride (CdTe) solar cell to improve the efficiency of the photovoltaic cell.

To improve the performances of CdTe thin-film solar cells, the thickness of CdTe and cadmium sulfide (CdS) have been modified separately. High-efficiency ultra-thin CdTe solar cell with ZnTe layer as back surface field (BSF) was achieved. The CdTe solar cell is under AM1.5 g illumination using a one-dimensional (1-D) model, i.e. personal computer one dimensional (PC1D).

The highest conversion efficiency of about 15.3 per cent was achieved for ultrathin CdTe solar cell with a ZnTe BSF layer. The results of simulation were compared with experimental and analytical results by other researchers.

In this paper, according to the authors’ knowledge ZnO:Al/CdS/CdTe/ZnTe is simulated by PC1D model for the first time and is compared with experimental result (ZnO:Al/CdS/CdTe). The results show a suitable performance.

Establishes a vision and a national (USA) strategy for civic networking. Encompasses citizen groups, voluntary organizations and local government, using an information infrastructure for public benefit. Outlines four “Grand Challenges”, a set of policy goals and a detailed agenda for action.

The purpose of this paper is to provide a review of recent developments in electromagnetic radiation (EMR) sensing.

Following a short introduction, this paper discusses a selection of recent research and development activities concerning the sensing of gamma radiation, X‐rays and ultraviolet (UV) radiation.

This shows that novel sensors are being developed for all of these classes of EMR. Improved gamma sensors are attracting strong interest in the USA, reflecting concerns regarding nuclear security. Novel X‐ray and UV sensors are often being developed in response to new and emerging uses of these types of radiation.

This paper provides a technical review of recent research into sensors for detecting gamma radiation, X‐rays and UV radiation.