Results 1 - 10 of 14415
Results 1 - 10 of 14415. Search took: 0.037 seconds
|Sort by: date | relevance|
[en] A method of noninvasive recovery of gas-discharge detectors degraded due to operation in intense radiation fields is described. The plasma-chemical reactions are the basis of the presented techniques; these reactions take place during the detector training in a gas discharge of special recovering gas mixtures. The results of recovery of operating parameters for proportional chambers and counters are presented.
[en] Graphical abstract: Schematic of the exhaust steam recovery in coal-fired CHP unit. Display Omitted -- Highlights: •A novel mechanism for exhaust steam waste heat recovery is proposed. •Pinch analysis and Sankey diagrams are used in the thermodynamic analysis. •The sensitivity analysis is performed and evaluated with several metrics. •The feasibility and techno-economic evaluation are considered. -- Abstract: Combined heat and power (CHP) has been identified as an important approach for fossil fuel utilization with high efficiency and pollutant concentration control. In this study, an optimized process for in-depth exhaust steam utilization was proposed to further exploit the energy saving potential of CHP unit. In the novel system, the utilization of the exhaust steam was combined with the heating process for air and condensate water, largely recovering the waste heat and leading to an improvement in the performance of the CHP unit. EBSILON Professional was used to build the model; and compared with the reference system, thermodynamic analysis and techno-economic evaluation were conducted to reveal the characteristics of the novel system. The results showed that, in the design condition, the exhaust steam utilization ratio in the novel system had a significant increment of 22.74% than that in the reference system, leading to a sharp increase of 16.26% in heating capacity and 0.83 MW in net electricity output, bringing about 5.06% improvement in net generating efficiency. Meanwhile, the net annual revenues of the novel system can reach 1.80 million USD.
[en] A proteomic study of Cunninghamella echinulata recovery during exposure to tributyltin was conducted with 2-D SDS-PAGE protein separation and profiling, MALDI-TOF/TOF protein identification, and PCA analysis. The presence of TBT resulted in an upregulation of enzymes related to energy production via cellular respiration. The unique overexpression of NADH dehydrogenase and mitochondrial malate dehydrogenase, together with an increased level of cytochrome c oxidase, ATP synthase subunits, and inorganic pyrophosphatase, indicates a strong energy deficit in the cells, leading to an increase in the ATP production. The overexpression of Prohibitin-1, a multifunctional protein associated with the proper functioning of mitochondria, was observed as well. The data also revealed oxidative stress condition. Among reactive oxygen species (ROS)–scavenging enzymes, only superoxide dismutase (SOD) showed active response against oxidative stress induced by the xenobiotic. The induction of a series of ROS-scavenging enzymes was supported by a microscopic analysis revealing a considerably large concentration of ROS in the hyphae. The overexpression of cytoskeleton-related proteins in the TBT presence was also noticed. The obtained results allow explaining the recovery strategy of the fungus in response to the energy depletion caused by TBT.
[en] Magnetic resonance imaging is effective for non-invasive detection of myocardial diseases by extracellular volume fraction (ECV) estimation. A new methodology for T1 and ECV mapping is tested in this work, comparing results with other well-consolidated methods. The associated level of uncertainty for data was also estimated, to assess the reliability of the technique. A phantom with known T1 values was used for reference, and 60 subjects (40 controls, 20 diseased patients) were examined, using the modified look-locker inversion-recovery (MOLLI) method. Obtained T1 data were studied in terms of accuracy (difference with reference T1), paired comparisons with other methods, and Gamma-tool analysis with tolerances criteria of 4.21 mm for distance-to-agreement, and between 2%–5% for T1 difference. Accuracy and precision of the T1 mapping was analysed by phantom measurements, and the uncertainty of the ECV was estimated by T1 error propagation. Differences (in paired comparisons) of T1 datasets were not significant neither for statistical tests, nor for Bland–Altman analysis. T1 accuracy was between −12% and −1% across methods, slightly better for the tested method (mean accuracy in the T1 range of interest better than 2%). The Gamma analysis confirm slightly better results for the tested method than other methodologies. The new method improves the computational efficiency by a factor of 25 (at least), revealing to be also more suitable for Big Data-related applications. (note)
[en] The object of the presented work is to establish by experimental way the importance of fatigue strength of samples of steel 45 and of steel tape of 50KHFA welded-on electric contact (EC) welding on the same material with using of intermediate nickel layer. (author)
[en] Here, we propose a novel method to identify inter-crystal scattering (ICS) events from a PET detector that is even applicable to light-sharing designs. In the proposed method, the detector observation was considered as a linear problem and ICS events were identified by solving this problem. Two ICS identification methods were suggested for solving the linear problem, pseudoinverse matrix calculation and convex constrained optimization. The proposed method was evaluated based on simulation and experimental studies. For the simulation study, an 8 × 8 photo sensor was coupled to 8 × 8, 10 × 10 and 12 × 12 crystal arrays to simulate a one-to-one coupling and two light-sharing detectors, respectively. The identification rate, the rate that the identified ICS events correctly include the true first interaction position and the energy linearity were evaluated for the proposed ICS identification methods. For the experimental study, a digital silicon photomultiplier was coupled with 8 × 8 and 10 × 10 arrays of 3 × 3 × 20 mm3 LGSO crystals to construct the one-to-one coupling and light-sharing detectors, respectively. Intrinsic spatial resolutions were measured for two detector types. The proposed ICS identification methods were implemented, and intrinsic resolutions were compared with and without ICS recovery. As a result, the simulation study showed that the proposed convex optimization method yielded robust energy estimation and high ICS identification rates of 0.93 and 0.87 for the one-to-one and light-sharing detectors, respectively. The experimental study showed a resolution improvement after recovering the identified ICS events into the first interaction position. The average intrinsic spatial resolutions for the one-to-one and light-sharing detector were 1.95 and 2.25 mm in the FWHM without ICS recovery, respectively. These values improved to 1.72 and 1.83 mm after ICS recovery, respectively. In conclusion, our proposed method showed good ICS identification in both one-to-one coupling and light-sharing detectors. We experimentally validated that the ICS recovery based on the proposed identification method led to an improved resolution. (paper)
[en] Highlights: •Various influencing factors of energy use in WWTPs are characterized. •Benchmark energy consumption in WWTPs in different countries are highlighted. •Energy recovery or saving technologies in WWTPs are summarized. •Recent advances in optimization of energy recovery technologies are highlighted. •Feasibility and challenges of energy self-sufficient WWTPs are explored. -- Abstract: Energy efficiency optimization is crucial for wastewater treatment plants (WWTPs) because of increasing energy costs and concerns about global climate change. Energy efficiency optimization can be achieved through a combination of energy recovery from the wastewater treatment process and energy saving-related technologies. Through these two approaches energy self-sufficiency of WWTPs is achievable, and research is underway to reduce operation costs and energy consumption and to achieve carbon neutrality. In this paper, we analyze energy consumption and recovery in WWTPs and characterize the factors that influence energy use in WWTPs, including treatment techniques, treatment capacities, and regional differences. Recent advances in the optimization of energy recovery technologies and theoretical analysis models for the analysis of different technological solutions are presented. Despite some challenges in implementation, such as technological barriers and high investment costs, particularly in developing countries, this paper highlights the potential for more energy self-sufficient WWTPs to be established in the future.
[en] The low availability of nitrogen (N) is one of the most important limiting factors impeding the increase in rice yield among the various factors. Split N fertilizer applications can play an important role in nutrient management strategy that is productive, profitable and environmentally responsible. In this study, the recoveries and efficiencies of a multiple-split N fertilizer application of were determined using 15N labeled fertilizer, in order to provide science-based foundation for the nitrogen management in sustainable rice production. A lysimeter experiment with five treatments in four replications was set-up T0 (control). T1 (45 kg N ha“- “1), T2 (90 kg N ha“- “1), T3 (135 kg N ha“- “1) and T4 (180 kg N ha“- “1). 15N tracer analysis showed that, on average, only 30% of applied N is recovered by the crop following one time basal application. In contrast, higher fertilizer nitrogen use efficiencies (FNUE) (>50%) were observed following multiple-split N application. The result of FNUE also corroborates with the significant increase in rice grain yield. Many crops, however, have different nutrient requirements, therefore as in all fertilization strategies, it is highly recommended that source, rate, time and place of application should be considered in making split fertilization decisions. (author)
[en] Purpose. This study was designed to determine the efficacy and mechanisms of radioprotection by the combination of gamma-tocotrienol (GT3) and pentoxifylline (PTX) against acute radiation injury. Materials and Methods. Post-irradiation survival was monitored to determine the most efficacious dose and time of administration of PTX. Dose reduction factor (DRF) was calculated to compare the radioprotective efficacy of the combination. To determine the mechanism of synergistic radioprotection by the combination, mevalonate or calmodulin were coadministered with the GT3-PTX combination. Mevalonate was used to reverse the inhibitory effect of GT3 on 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), and calmodulin was used to reverse the inhibition of phosphodiesterase (PDE) by PTX. Results. The combination was most effective when 200 mg/kg of PTX was administered 15 min before irradiation along with 200 mg/kg of GT3 (−24 h) and resulted in a DRF of 1.5. White blood cells and neutrophil counts showed accelerated recovery in GT3-PTX-treated groups compared to GT3. Mevalonate had no effect on the radioprotection of GT3-PTX; calmodulin abrogated the synergistic radioprotection by GT3-PTX. Conclusion. The mechanism of radioprotection by GT3-PTX may involve PDE inhibition
[en] Nanotechnology is an emerging technology with the potential to effect revolutionary changes in several aspects of the oil and gas industry such as exploration, drilling, production, enhanced oil recovery, refining and processing. The importance of this emerging technology in petroleum industry represents a special challenge and opportunity to restructure teaching and nurture the scientific and workplace of the 21th century. This paper presents an overview of application of nanotechnology in the oil and gas industry in order to assess the importance and the potential technical benefits of this new emerging technology in petroleum industry. As a consequence of this rapid development and board impact of nanotechnology, education and training of new generation of engineering workplace will play an important role in petroleum industry. In this regard, the effort to meet such demand while appropriately addressing and improving collaboration between the industry and academia, there is a strong need to introduce nanoscience technology into existing petroleum curriculum program. It is hoped that this work would be beneficial to both petroleum engineering education and research and will stimulate some ideas for academics, who may face themselves with the developing education course and teaching nanotechnology in the near future. (author)