Gas phases of ethylene oxide and propylene oxide, commonly used for technical alcoxylation reactions, can decompose explosively with an enormous temperature and pressure rise even without the presence of air. For the estimation of consequences of such reactions explosion pressures and rates of pressure rise of EO and certain mixtures of ethylene oxide and propylene oxide at temperatures between 100 °C and 200 °C and pressures between 1 bar and 10 bar were determined experimentally using vessels with volumes of 3 dm3 and 100 dm3. 相似文献
Thermionic electron emitters are a crucial component in applications ranging from high power telecommunication, electron guns, space thrusters and direct thermal to electrical energy converters. One key characteristic of diamond based electron sources is the negative electron affinity (NEA) properties of hydrogen terminated surfaces which can significantly reduce the emission barrier. Nitrogen and phosphorus doped diamond films have been prepared by plasma assisted chemical vapor deposition on metallic substrates for thermionic emitter application. Electron emission current versus temperature was measured and analyzed with respect to the Richardson-Dushman relation, with work function and Richardson constant deduced from the results. Initial emission measurements up to 500 °C in vacuum were followed by emitter characterization while the sample was exposed to methane. Vacuum measurements indicated a work function of 1.18 eV and 1.44 eV for phosphorus and nitrogen doped diamond films, respectively. Introduction of methane resulted in a significant increase of the emission current which was ascribed to contribution from ionization processes which increase charge transfer from the emitter surface. This phenomenon was utilized in a thermionic energy conversion structure by introduction of methane in the inter electrode gap where a two-fold increase in output power was observed upon introduction of the gaseous species. 相似文献
Margarines and shortenings available in Austria were repeatedly sampled in 1991/1992 and the content oftrans fatty acids (TFA) determined by using capillary GLC. Wide variations of the TFA contents with respect to intra- and inter-brand differences were observed. Diet margarines contained up to 1% TFA, while TFA concentrations in tub or stick margarines were much higher (15.7±5.8% and 21.3±5.3%, respectively). A sub-set of samples was also purchased in 1995 and a general reduction of the TFA content was noticed. Taking into account different market shares of certain margarine types, a weighted average of 15.7% TFA and 6.5% TFA was calculated for the 1991/1992 and the 1995 samples. Based on availability data the amount of TFA supplied with margarines was estimated to be 3.7 g per person per day, while a more accurate method of measuring dietary intakes, i.e. diet history and food frequency data, approximates the amount of TFA supplied with margarines to be 1.5 g per person per day for the 1991/1992 samples and 0.6 g for the 1995 samples. 相似文献
The measurement of the spectral power distribution (SPD) of a radiation source by array spectroradiometers is a technique that is widely used. In many applications, quantities that are derived from the SPD by a weighted integral over a wavelength interval are of interest. These integral quantities ought to be accompanied by a reliable uncertainty statement, for example, to assess conformity with prescribed limits or in order to judge the consistency of results obtained at different laboratories. We have developed a generally applicable Monte Carlo procedure for evaluating the uncertainty of spectral measurements. The procedure naturally accounts for correlations in the SPD which turn out to be crucial. Means are provided to handle and transfer these large‐scale correlation matrices easily. The proposed approach is illustrated by the determination of the SPD of colored LEDs from array spectroradiometer measurements, together with the derived CIE 1931 color coordinates. MATLABTM software implementing the proposed analysis procedure is made available. 相似文献
We compare various extensions of the Bradley–Terry model and a hierarchical Poisson log-linear model in terms of their performance in predicting the outcome of soccer matches (win, draw, or loss). The parameters of the Bradley–Terry extensions are estimated by maximizing the log-likelihood, or an appropriately penalized version of it, while the posterior densities of the parameters of the hierarchical Poisson log-linear model are approximated using integrated nested Laplace approximations. The prediction performance of the various modeling approaches is assessed using a novel, context-specific framework for temporal validation that is found to deliver accurate estimates of the test error. The direct modeling of outcomes via the various Bradley–Terry extensions and the modeling of match scores using the hierarchical Poisson log-linear model demonstrate similar behavior in terms of predictive performance.
Reprimo-like (RPRML) is an uncharacterized member of the Reprimo gene family. Here, we evaluated the role of RPRML and whether its regulation by DNA methylation is a potential non-invasive biomarker of gastric cancer. RPRML expression was evaluated by immunohistochemistry in 90 patients with gastric cancer and associated with clinicopathologic characteristics and outcomes. The role of RPRML in cancer biology was investigated in vitro, through RPRML ectopic overexpression. Functional experiments included colony formation, soft agar, MTS, and Ki67 immunofluorescence assays. DNA methylation-mediated silencing was evaluated by the 5-azacytidine assay and direct bisulfite sequencing. Non-invasive detection of circulating methylated RPRML DNA was assessed in 25 gastric cancer cases and 25 age- and sex-balanced cancer-free controls by the MethyLight assay. Downregulation of RPRML protein expression was associated with poor overall survival in advanced gastric cancer. RPRML overexpression significantly inhibited clonogenic capacity, anchorage-independent growth, and proliferation in vitro. Circulating methylated RPRML DNA distinguished patients with gastric cancer from controls with an area under the curve of 0.726. The in vitro overexpression results and the poor patient survival associated with lower RPRML levels suggest that RPRML plays a tumor-suppressive role in the stomach. Circulating methylated RPRML DNA may serve as a biomarker for the non-invasive detection of gastric cancer. 相似文献
In β-thalassemia, ineffective erythropoiesis leads to anemia and systemic iron overload. The management of iron overload by chelation therapy is a standard of care. However, iron chelation does not improve the ineffective erythropoiesis. We recently showed that the oral ferroportin inhibitor VIT-2763 ameliorates anemia and erythropoiesis in the Hbbth3/+ mouse model of β-thalassemia. In this study, we investigated whether concurrent use of the iron chelator deferasirox (DFX) and the ferroportin inhibitor VIT-2763 causes any pharmacodynamic interactions in the Hbbth3/+ mouse model of β-thalassemia. Mice were treated with VIT-2763 or DFX alone or with the combination of both drugs once daily for three weeks. VIT-2763 alone or in combination with DFX improved anemia and erythropoiesis. VIT-2763 alone decreased serum iron and transferrin saturation (TSAT) but was not able to reduce the liver iron concentration. While DFX alone had no effect on TSAT and erythropoiesis, it significantly reduced the liver iron concentration alone and in the presence of VIT-2763. Our results clearly show that VIT-2763 does not interfere with the iron chelation efficacy of DFX. Furthermore, VIT-2763 retains its beneficial effects on improving ineffective erythropoiesis when combined with DFX in the Hbbth3/+ mouse model. In conclusion, co-administration of the oral ferroportin inhibitor VIT-2763 and the iron chelator DFX is feasible and might offer an opportunity to improve both ineffective erythropoiesis and iron overload in β-thalassemia. 相似文献
Detecting, locating and repairing faults is a hard task. This holds especially in cases where dependent failures occur in
practice. In this paper we present a methodology which is capable of handling dependent failures. For this purpose we extend
the model-based diagnosis approach by explicitely representing knowledge about such dependencies which are stored in a failure
dependency graph. Beside the theoretical foundations we present algorithms for computing diagnoses and repair actions that
are based on these extensions. Moreover, we introduce a case study which makes use of a larger control program of an autonomous
and mobile robot. The case study shows that the proposed approach can be effectively used in practice. 相似文献
The aviation organization is creating awareness for the overall reduction of NOx emissions by up to 80% in the near future. This motivates to conduct research on the current state of art, catalytic stabilized combustion chamber using hydrogen. This was achieved by performing an experimental parametric investigation of Platinum catalysts in two phases. Firstly, the design of three diverse configurations of mixers and was investigated experimentally and numerically. The chosen mixer was implemented in the parametric study of five different Pt catalysts varying in geometric and material properties. This was executed at unpressurized and NOx emission solely due to the catalytic reaction was examined for varying thermal power and air/fuel ratios. Furthermore, temperatures were recorded. Additionally, CFD simulation was accomplished and compared with the measurement data. The overall least NOx achieved was 7.5 ppm at 5 kW for the metal catalyst. The result of this work proposed suitable catalyst for the development of a combined combustor configuration (including catalyst and combustion chamber) which will be intended for small aircraft engine applications. 相似文献