6,796 research outputs found

    Implementing financial management and governance in transitional states: reflections on introducing Western normative models of public internal financial control in the new Republic of Kosovo

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    After an early career in accountancy, corporate management and consulting in England, Bermuda and Canada an opportunity presented itself to embark on a new career in international development consultancy. A series of public finance reform assignments in the Caribbean, South America, Eastern Europe, South East Asia and Southern Africa provided the foundation for my work in the Republic of Kosovo which is the source of the public works that are submitted with this paper. Over a period of four years I was engaged in three projects to introduce the European Union’s Public Internal Financial Control financial governance model to Kosovo, a poor, corrupt new country hoping to gain admittance to the EU. This work involved applying international best practices to developing financial management policy, laws and regulations supported by strategic plans, multi-level capacity building initiatives and a change management strategy to drive future interventions. Taken together these projects represent a uniquely integrated intervention that touched all levels of government and has been independently evaluated as having had considerable positive impact on the development of Kosovo. Despite the positive outcomes, an examination of the limitations of the best practices model encountered in my work and in the observations of various professional and academic commentators, suggests a more effective way forward: developing country-specific, principles-based interventions rather than imposing western normative models, with the involvement of a broader set of actors that includes civil society and informal actors

    Silicon solar cell process development, fabrication and analysis

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    For UCP Si, randomly selected wafers and wafers cut from two specific ingots were studied. For the randomly selected wafers, a moderate gettering diffusion had little effect. Moreover, an efficiency up to 14% AMI was achieved with advanced processes. For the two specific UCP ingots, ingot #5848-13C displayed severe impurity effects as shown by lower 3sc in the middle of the ingot and low CFF in the top of the ingot. Also the middle portions of this ingot responded to a series of progressively more severe gettering diffusion. Unexplained was the fact that severely gettered samples of this ingot displayed a negative light biased effect on the minority carrier diffusion length while the nongettered or moderately gettered ones had the more conventional positive light biased effect on diffusion length. On the other hand, ingot C-4-21A did not have the problem of ingot 5848-13C and behaved like to the randomly selected wafers. The top half of the ingot was shown to be slightly superior to the bottom half, but moderate gettering helped to narrow the gap

    Recent advances in GaAs/Ge solar cells

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    By growing the GaAs cell on a Ge substrate, the advantages of GaAs cells can be retained and the higher mechanical strength of the Ge makes larger, thinner GaAs cells possible. To conform to immediate user requirements, GaAs growth conditions were modified to eliminate the additional PV output at GaAs/Ge interface. To demonstrate acceptable cell manufacturing technology, the major areas in cell manufacture were analyzed and developed, and efficiency combined. Also the cells were successfully assembled on current lightweight arrays. The main areas of effort are discussed

    Microcrystalline silicon growth for heterojunction solar cells

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    Microcrystalline Si (m-Si) films with a 1.7eV energy bandgap and crystal size of several hundred A were e-beam evaporated on single crystalline Si (c-Si) to form a heterojunction with the substrate, or a window layer to a single crystalline p-n junction (heteroface structure). The goal was to enhance Voc by such uses of the larger bandgap m-Si, with the intriguing prospect of forming heterostructures with exact lattice match on each layer. The heterojunction structure was affected by interface and shunting problems and the best Voc achieved was only 482mV, well below that of single crystal Si homojunctions. The heteroface structure showed promise for some of the samples with p m-Si/p-n structure (the complementary structure did not show any improvement). Although several runs with different deposition conditions were run, the results were inconsistent. Any Voc enhancement obtained was too small to compensate for the current loss due to the extra absorption and poor carrier transport properties of the m-Si film

    Silicon solar cell process development, fabrication and analysis

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    Solar cells were fabricated from EFG ribbons dendritic webs, cast ingots by heat exchanger method, and cast ingots by ubiquitous crystallization process. Baseline and other process variations were applied to fabricate solar cells. EFG ribbons grown in a carbon-containing gas atmosphere showed significant improvement in silicon quality. Baseline solar cells from dendritic webs of various runs indicated that the quality of the webs under investigation was not as good as the conventional CZ silicon, showing an average minority carrier diffusion length of about 60 um versus 120 um of CZ wafers. Detail evaluation of large cast ingots by HEM showed ingot reproducibility problems from run to run and uniformity problems of sheet quality within an ingot. Initial evaluation of the wafers prepared from the cast polycrystalline ingots by UCP suggested that the quality of the wafers from this process is considerably lower than the conventional CZ wafers. Overall performance was relatively uniform, except for a few cells which showed shunting problems caused by inclusions

    Silicon solar cell process development, fabrication, and analysis

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    Two large cast ingots were evaluated. Solar cell performance versus substrate position within the ingots was obtained and the results are presented. Dendritic web samples were analyzed in terms of structural defects, and efforts were made to correlate the data with the performance of solar cells made from the webs

    Radiation resistance of Ge, Ge0.93Si0.07, GaAs and Al0.08Ga0.92 as solar cells

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    Solar cells made of Ge, Ge(0.93)Si(0.07) alloys, GaAs and Al(0.08)Ga(0.92)As were irradiated in two experiments with 1-meV electrons at fluences as great as 1 x 10(exp 16) cm(exp-2). Several general trends have emerged. Low-band-gap Ge and Ge(0.93)Si(0.07) cells show substantial resistance to radiation-induced damage. The two experiments showed that degradation is less for Al(0.08)Ga(0.92)As cells than for similarly irradiated GaAs cells. Compared to homojunctions, cells with graded-band-gap emitters did not show the additional resistance to damage in the second experiment that had been seen in the first. The thickness of the emitter is a key parameter to limit the degradation in GaAs devices

    Heterostructure solar cells

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    The performance of gallium arsenide solar cells grown on Ge substrates is discussed. In some cases the substrate was thinned to reduce overall cell weight with good ruggedness. The conversion efficiency of 2 by 2 cm cells under AMO reached 17.1 percent with a cell thickness of 6 mils. The work described forms the basis for future cascade cell structures, where similar interconnecting problems between the top cell and the bottom cell must be solved. Applications of the GaAs/Ge solar cell in space and the expected payoffs are discussed

    Trigger R&D for CMS at SLHC

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    CERN has made public a comprehensive plan for upgrading the LHC proton-proton accelerator to provide increased luminosity commonly referred to as Super LHC (SLHC) [1]. The plan envisages two phases of upgrades during which the LHC luminosity increases gradually to reach between 6-7×1034 cm-2sec-1. Over the past year, CMS has responded with a series of workshops and studies which have defined the roadmap for upgrading the experiment to cope with the SLHC environment. Increased luminosity will result in increased backgrounds and challenges for CMS and a major part of the CMS upgrade plan is a new Level-1 Trigger (L1T) system which will be able to cope with the high background environment at the SLHC. Two major CMS milestones will define the evolution of the CMS trigger upgrades: The change of the Hadronic Calorimeter electronics during phase-I and the introduction of the track trigger during phase-II. This paper outlines alternative designs for a new trigger system and the consequences for cost, latency, complexity and flexibility. In particular, it looks at how the trigger geometry of CMS could be mapped onto the latest generation of hardware while remaining backwards compatible with current infrastructure. A separate paper presented at this conference [2] looks at what could be possible if large parts of the trigger system were changed, or additional hardware added to create a time multiplexed trigger system
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