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[en] This study focuses on the demand and supply of seasonal swing in the northwest European gas market and the role of gas storage facilities therein. We apply a statistical analysis to analyse historic developments and a model-based analysis to analyse possible future developments with respect to northwest European swing demand and supply. The latter analysis provides projections for swing demand and gas storage developments until the year 2030. We analyse various scenarios with respect to future gas demand and seasonal flexibility characteristics of different gas supply options. Within the framework and assumptions used in our model-based analysis we find that northwest Europe needs to increase its gas storage capacity within a business-as-usual scenario as well as in alternative lower demand scenario. In order to realise the needed seasonal gas storage capacity, a substantial amount of projects currently planned need to go ahead.
[en] Temperature dependent a.c. capacitance (C) together with ac conductance(G/ω) under various frequency (ω) and d.c. current (I) measurements as a function of bias (V) were employed to investigate both majority and minority carrier injection phenomenon on chromium- p type crystalline silicon (Cr/p-cryst. Si) Schottky diode. This ambipolar transport process behaved differently according to the mentioned techniques: under forward bias, there was a increase in capacitance towards maximum while majority carrier injection proceed from the back electrode.Meanwhile, minority carrier injection from front electrode cause to sharp decrease in measured capacitance from peak position, leading to observation a hump in C-V analysis and followed up tendency due might be interface states and finally end up with constancy. Moreover, shape and peak position of the hump had both frequency and temperature dependency. Remarkably, in the bias range where hump observed, space charge limited current (SCLC) was discerned as the actual enrolled current flow mechanism in I-V measurement, confirming further majority carrier injection. In addition, both dc conductivity and ac conductance behaved similarly. On the other side, reverse current seemed proportional to square root of reverse bias where constancy of capacitance appeared. These experimental identifications simply imposed the existence of conductivity modulation issue in metal-semiconductor (MS) junction which relies on majority carriers and mostly minority carrier injection is disregarded. Obviously, minority carrier injection played indispensable role in both I-V and C-V measurements by reducing diode series resistance (Rs) and improving rectification ratio (forward current/reverse current) and observation of hump
[en] The electricity market in Germany is likely to undergo several significant structural changes over the years to come. Here one may think of Germany's ambitious renewable agenda, the disputed decommissioning of nuclear facilities, but also unbundling of TSO's as enforced by European regulation. This study is a scenario-based analysis of the impact of different realizations of known investment plans for transmission and generation capacity on the future German power market while accounting for internal congestion. For this analysis the static equilibrium model of the European electricity market COMPETES is deployed, including a 10-node representation of the German highvoltage grid. Results for the multi-node analysis indicate that price divergence and congestion are likely to arise in the German market as renewable additions affecting mainly the North of Germany, the debated decommissioning of nuclear facilities in the South, and the expected decommissioning of coal-fired facilities in Western Germany appear to render current investment plans for transmission capacity insufficient. The current system of singlezone pricing for the German market may therewith be compromised. However, transmission additions would not benefit all market parties, with producers in exporting regions and consumers in importing regions being the main beneficiaries. Vertical unbundling of German power companies could increase the incentive for constructing transmission lines if generation capacity would cause Germany to be a net-importing country. In case Germany remains a net-exporting country, the effects of vertical unbundling on cross-border capacity are less clear cut.
[en] At the title workshops the Dutch research in wind energy, its progress, results and plans will be discussed with the international wind energy industry. This report bundles the presentations of the unit Wind Energy of the Energy research Centre of the Netherlands (ECN)
[en] The purpose of the present study was to retrospectively investigate the chest radiograph (CR) and CT findings of childhood pneumonia complicated by cavitary necrosis, and to evaluate the role of CT in decision-making for surgical intervention. Chest CT was performed in 51 patients presenting with persistent or progressive pneumonia, respiratory distress and sepsis despite 710 days of appropriate antibiotic treatment and closed tube drainage. Chest radiograph and CT findings were retrospectively evaluated in 23 patients (45%) with cavitary necrosis. Chest radiographs showed consolidation in 19 of 23 patients, cavitation in five patients, parapneumonic effusions in 17 patients and airfluid levels in the pleural space in one patient. The CT scans demonstrated consolidation and cavitary necrosis in all patients. There were parapneumonic effusions in all patients with concomitant loculated collections in six patients. Twenty-two of 23 patients had pleural thickening. In seven patients there were airfluid levels in the pleural space. In five of these patients, CT scans demonstrated bronchopleural fistulae. On the basis of the CT and clinical findings, 11 patients underwent surgical intervention. Computed tomography is superior to CR for demonstrating cavitary necrosis complicating pneumonia, and other parenchymal and pleural complications. It also has a crucial decision-making role for surgery. Copyright (2004) Blackwell Science Pty Ltd
[en] To evaluate the potential use of multi-slice computed tomography urography (MSCTU) after diuretic injection in children with urinary tract dilatation. MSCTU was performed in 19 patients (11 boys, 8 girls, mean age 5.4 years) with suspicion of urinary tract obstruction and dilatation. Furosemide, 1 mg/kg, was injected 3 min before contrast material administration and followed by a bolus of 30 ml of physiologic saline solution immediately after application of contrast material. Excretory-phase images were obtained through the abdomen and pelvis beginning 10 min after initiation of the injection of contrast material. Maximum intensity projection (MIP) and volume rendering (VR) images were post-processed to obtain urographic views. MSCTU revealed pathology in 16 of 19 patients, while 3 patients had normal findings. Ureteropelvic obstruction was found in 4 patients, obstructive megaureter in 8. Both ureteropelvic obstruction and obstructive megaureter were disclosed in 1 patient, partial ureteral duplication in 1 patient, and both complete ureteral duplication and ureterocele in 2 patients. In all patients, MIP and VR images could satisfactorily show the pathologies of the urinary tract. The estimated effective average doses of MSCTU were higher than IVU. Preliminary results of furosemide-enhanced MSCTU demonstrated consistently dilated urinary tracts, obstruction levels, and underlying pathologies better than US and IVU
[en] A renewable obligation (RO) combined with tradable renewable energy certificates is a market-based instrument used to promote the production of electricity from renewable energy sources. A renewable obligation is an alternative for subsidies. A renewable obligation will only be an efficient instrument if certificate markets are efficient. This requires that there is no market power and no anti-competitive behaviour on the certificate market. If the current developments in Dutch renewable energy production continue, market power on a future renewable certificate market in the Netherlands will probably not be an issue, even if the RO should only rest on the retail market instead of on the whole electricity market. A renewable obligation will raise the retail price for consumers, thereby reducing consumer surplus. Simulations show that the retail electricity price increases with 30 euro per MWh to a level of 104 euro per MWh in case of a 30% renewable target. Consumer surplus is reduced with 19% compared to the baseline scenario. In contrast, a subsidy such as the Dutch SDE (Promoting Renewable Energy scheme or 'Stimulering Duurzame Energie') which is financed from the state budget has the effect to (slightly) lower the retail electricity price, thereby increasing consumer surplus. It should however be realised that the costs of the subsidy will indirectly affect electricity consumers through their tax payments.
[en] Al doped ZnO (ZnO:Al) thin films were prepared using a sol–gel dip coating technique and deposited on borosilicate glass substrates. The irradiation treatment, was conducted using Co-60 radioisotope, played an important role in enhancing electrical properties. The absorbed dose was a key parameter to decrease the electrical resistivity and to increase carrier density and carrier mobility of nanospherical ZnO:Al thin film. ZnO:Al thin film with the doping of Al at 0.8 at% had the lowest electrical resistivity and the highest optical transmittance after the irradiation treatment. Optical properties, such as transmittance and reflectance, were affected at an absorbed dose of 0.2 Gy. The curves of optical density were improved at ∼380, 420, and 520 nm in visible range after the irradiation process. Besides, another characteristic optical density band between∼900 and 1100 nm was enhanced by gamma irradiation. It has been suggested that the mechanism of absorption is related to an allowed direct transition at the irradiated ZnO:Al thin film on borosilicate glass. The optical band gap of the ZnO:Al thin films broadened with increasing doping concentration. However, there is a decrease in optical energy gap of ZnO:Al thin film along with the absorbed dose of the film. - Highlights: • Gamma radiation affected the nanospherical structure of film depending on the cumulative dose. • Resistivity, carrier density and carrier mobility were improved by Co-60 radioisotope. • There is a relation between improvement of electrical and optical properties of irradiated film
[en] The fact that depletion of indigenous gas production increases gas import dependency is widely known and accepted. However, there is considerable less attention for the implications of indigenous resource depletion for the provision of seasonal flexibility. The traditionally largest source of seasonal flexibility in Europe is indigenous gas production, mainly based in the Netherlands and the United Kingdom. With the depletion of indigenous sources the market increasingly needs to rely on other sources for seasonal flexibility, such as gas storage facilities. We investigate the future need for gas storage as a source for seasonal flexibility provision using a dynamic gas market model (GASTALE) in which different potential sources for seasonal flexibility - gas production, imports via pipeline, LNG imports and storage facilities - compete with each other in a market-based environment. The inclusion of seasonal flexibility properties in a gas market model allows a more complex analysis of seasonal flexibility issues than previously documented in literature. This is demonstrated in an analysis of the future demand for gas storage in northwestern Europe until 2030. Our results indicate that there is substantial need for additional gas storage facilities and thus supports current project proposals for new investment in gas storage facilities.
[en] This study reports on an evaluation of borides formed on AISI P20 steel substrate. Boronizing was performed at 800, 875 and 950 deg. C for 2, 4, 6 and 8 h by using Ekabor 2 powders. The hardness of borides measured by means of Vickers indenter was about 1500 HVN. The depth of boride layers depending on temperature and process time was ranged from 10 to 180 μm. The presence of borides (e.g., FeB, Fe2B, MnB, CrB) was confirmed by X-ray diffraction (XRD) analysis technique. SEM cross-sectional examinations revealed that borides formed on AISI P20 has columnar morphology. Depending on the process time, fracture toughness of borides formed on the surface of AISI P20 mold steel ranged from 2.79 to 4.79 MPa m1/2. Kinetic studies show a parabolic relationship between layer thickness and process time, and the activation energy is calculated as 200 kJ/mol. Moreover, an attempt was made to investigate the possibility of predicting the iso-thickness of boride layer variation and to establish an empirical relationship between process parameters of boriding and boride layer