1,074 research outputs found

    Energy efficiency in the Chinese provinces:a fixed effects stochastic frontier spatial Durbin error panel analysis

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    Energy efficiency improvement has been a key objective of China's long- term energy policy. In this paper, we derive single-factor technical energy efficiency (abbreviated as energy efficiency) in China from multi-factor efficiency estimated by means of a translog production function and a stochastic frontier model on the basis of panel data on 29 Chinese provinces over the period 2003-2011. We find that average energy efficiency has been increasing over the research period and that the provinces with the highest energy efficiency are at the east coast and the ones with the lowest in the west, with an intermediate corridor in between. In the analysis of the determinants of energy efficiency by means of a spatial Durbin error model both factors in the own province and in first-order neighboring provinces are considered. Per capita income in the own province has a positive effect. Furthermore, foreign direct investment and population density in the own province and in neighboring provinces have positive effects, whereas the share of state-owned enterprises in Gross Provincial Product in the own province and in neighboring provinces has negative effects. From the analysis it follows that inflow of foreign direct investment and reform of state-owned enterprises are important policy handles

    Studies of current collection configurations and sealing for tubular hybrid-DCFC

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    Direct Carbon Fuel Cells (DCFC) offer efficient conversion of coal or biomass derived carbons to electricity. A Hybrid Direct Carbon Fuel Cell (HDCFC) is a type of DCFCs that combines solid oxide cell geometry with a molten carbonate fuel cell electrode. This study focused on investigating different current collection configurations and sealant for tubular HDCFC concept. A HDCFC used a gadolinia doped ceria (GDC) or a YSZ as the electrolyte, in composites with NiO and LSM as the anode and the cathode, respectively. Three different current collection configurations of HDCFC were investigated by AC impedance in order to study the electrochemical phenomena that occur at the electrodes surface. The AC impedance results showed that both the surface area and the position of the current collector inside of the anode chamber affect drastically both the series resistance (Rs) and the polarisation resistance (Rp) values. The lowest total resistance (Rtot) was achieved on Configuration b with silver wire interwoven nickel mesh attached to the side of the anode wall by silver paste (Rtot = 2.98 Ω) and while the highest Rtot was achieved on the configuration c with silver wire interwoven nickel mesh inserted into the mixture of carbon and carbonate (Rtot = 149 Ω). The leak test carried out on several sealants demonstrated that composite sealants of Toku P-24 paste and an alumina silicate disc produced a low degree of leaks due to both the high resistance to the carbonate mixture and high density sealing after curing compared to the ceramabond.PostprintPeer reviewe

    Spontaneous retroperitoneal hematoma associated with iliac vein rupture

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    ObjectiveSpontaneous retroperitoneal hematoma (SRH) associated with iliac vein rupture is a rare but life-threatening emergency with high operative mortality. This study summarizes our experience in providing diagnostic and therapeutic management for this rare clinical entity.MethodsBetween May 2002 and May 2009, nine patients were admitted to our hospital for SRH and acute deep venous thrombosis (DVT). Medical data for demographics, clinical presentation, auxiliary examinations, treatment modalities, outcomes, and follow-up were retrospectively analyzed.ResultsNine patients (8 women, 1 man) were enrolled in this study. All were aged >45 years (range, 46-70 years). The common clinical manifestations were sudden onset of left lower abdominal or lumbar pain, swelling of the left lower extremity, anemia, and hypotension. Most patients were diagnosed by duplex ultrasound imaging and computed tomography scan. Three patients were treated conservatively, and six underwent surgical or combined treatments, comprising 2 repairs of iliac vein, 1 iliac vein ligation and Palma-Dale bypass graft, 1 pelvic vein ligation, 1 removal of hematoma, and 1 repair of iliac vein, thrombectomy, and endovascular stent placement. The iliac vein ruptured in five patients. May-Thurner syndrome was found in three patients. One patient died after surgery (operative mortality, 16.7%). Postoperative morbidity was 50%. Mean volume of perioperative blood transfusion was 900 ± 640 mL (range, 0-2000 mL). Mean lengths of stay were 2.7 ± 1.4 days (range, 2-5 days) in the intensive care unit and 16.9 ± 2.4 days (range, 14-21 days) in the hospital. Eight patients were postoperatively treated with 6 months of warfarin. Mean follow-up was 30.5 ± 15.0 months (range, 6-50 months). The occurrence rate of chronic venous insufficiency was 87.5% during follow-up.ConclusionsSRH with concomitant DVT, especially in women aged >45, should be considered in patients with sudden lower abdominal or lumbar pain, leg swelling, anemia, and shock. Spontaneous iliac vein rupture and the presence of May-Thurner syndrome should be considered in these patients. Surgical interventions were associated with high mortality and morbidity. In our experience, conservative therapy was safer than open surgical procedures

    Endovascular stent-graft placement and coil embolization for an anomalous splenic artery aneurysm

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    Aneurysms of the splenic artery originating anomalously from the superior mesenteric artery are extremely rare; however, they are clinically important because of the potential for fatal rupture and particular anatomical location. Most previous cases were managed by open surgical intervention. We present a case of an anomalous splenic artery aneurysm, which was successfully treated with endovascular stent graft placement and coil embolization. This appears to be a promising minimally invasive approach to manage this rare entity. Also, we review the literature of aneurysms of the splenic artery arising from the superior mesenteric artery

    Comparative study of durability of hybrid direct carbon fuel cells with anthracite coal and bituminous coal

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    The author would like to acknowledge the funding support of “Efficient Conversion of Coal to Electricity-Direct Coal Fuel Cell” with the grant number “RFCR-CT-2011-00004” from the Research Fund for Coal & Steel of the European commission. CJ acknowledges the Royal Society of Edinburgh for a RSE BP Hutton Prize in Energy Innovation.Direct carbon fuel cells offer the opportunity of generating energy from coal at high efficiency as an alternative to the procedure of conventional power plants. In this study, raw anthracite coal and raw bituminous coal were investigated in a hybrid direct carbon fuel cell (HDCFC), which was a combination of a solid oxide fuel cell and a molten carbonate fuel cell. Mechanical mixing was confirmed to be an efficient method of mixing coal with carbonate. The coal samples had different properties, for example, carbon content, hydrogen content, volatile matter and impurities. The results showed that the maximum power density obtained by the cell with anthracite coal was similar to that obtained by the cell with bituminous coal. It was found that the total power output from coal in HDCFCs mostly depended on the carbon content, while volatile matter, hydrogen content, moisture, etc. had an effect on the short-term durability. HDCFCs were kept operating for more than 120 h with 1.6 g coal. This study demonstrates that energy can be generated efficiently by employing anthracite and bituminous coal in hybrid direct carbon fuel cells.PostprintPeer reviewe

    Profitability analysis of Chinese listed firms: 1992-2004

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