891 research outputs found
Heating And Air-conditioning Technology For Radiant Heat Recovery In Kiln Wall Of Cement Plant
There is a large amount of energy waste in the cement production process, in which the waste of rotary kiln heat and the waste of high temperature exhaust gas at the kiln tail are the most serious. Therefore, the full and reasonable utilization of this waste heat resource is an important measure to improve the utilization degree and energy efficiency of waste heat, effectively reduce the heat pollution caused by waste heat emission to the environment, and protect the ecological environment. It is of great significance to realize energy conservation and emission reduction and regional sustainable development. The strategic goals are extremely important. At present, the waste heat mainly used by cement plants is the high-temperature flue gas at the kiln head and kiln tail, and there are few cases of recycling the radiant heat of the kiln tube wall. Therefore, based on the data provided by a cement plant in Shandong Province, China, a set of waste heat recovery equipment for the rotary kiln of a cement plant is designed. According to actual needs, a suitable lithium bromide absorption refrigeration unit and heat exchanger are selected to determine the waste heat utilization plan in winter, summer and transition season and make economic analysis
A Natural Wind Defrosting, Nano-coated Antibacterial Self-cleaning Energy-saving Health Air-cooled Refrigerator
The air-cooled frost-free household refrigerator is popular in the market because of its large size and frost-free size. However, the evaporator defrost process consumes a large amount of electrical energy to limit the wide spread of this refrigerator, at the same time because of its structural problems, resulting in its evaporator, air duct can not be artificially cleaned, leading to the growth of bacteria, pollution of food storage. This research has developed a self-cleaning energy-saving health refrigerator that uses indoor natural wind defrosting, ultra-hydrophilic nano-titanium dioxide coating photocatalytic sterilization and sterilization. After experimental comparison, under the same operating time of the same operating conditions, the refrigeration mode saves 1.5%, the defrost process saves 95%, reduces the amount of frosting by 23%, the temperature changes of the freezer is less than 7 ℃ , and the desterilization rate of nano-coated reaches 80%
Multi-Level Data-Driven Battery Management: From Internal Sensing to Big Data Utilization
Battery management system (BMS) is essential for the safety and longevity of lithium-ion battery (LIB) utilization. With the rapid development of new sensing techniques, artificial intelligence and the availability of huge amounts of battery operational data, data-driven battery management has attracted ever-widening attention as a promising solution. This review article overviews the recent progress and future trend of data-driven battery management from a multi-level perspective. The widely-explored data-driven methods relying on routine measurements of current, voltage, and surface temperature are reviewed first. Within a deeper understanding and at the microscopic level, emerging management strategies with multi-dimensional battery data assisted by new sensing techniques have been reviewed. Enabled by the fast growth of big data technologies and platforms, the efficient use of battery big data for enhanced battery management is further overviewed. This belongs to the upper and the macroscopic level of the data-driven BMS framework. With this endeavor, we aim to motivate new insights into the future development of next-generation data-driven battery management
Research On Waste Heat Recovery Of Low Temperature Flue Gas In Cement Plant And New Type Heat Exchange
Based on the measured data of low-temperature waste gas at the outlet of waste heat boiler of a new dry cement production line in a cement factory in China, this paper investigates the utilization of waste heat, and formulates the technical scheme of waste heat utilization, and focuses on the design of the key waste heat exchanger for waste heat utilization, and carries out technical and economic analysis. According to our calculation results, the low-temperature waste heat recovery of cement plant has great potential. Using this technology can save more energy and obtain good economic benefits.In addition, a new type of heat pipe heat exchanger is designed and briefly introduced in this paper, aiming at the current situation that the existing heat exchange equipment only has heat exchange function without considering dust removal function.The design inspiration of the new type of heat pipe heat exchanger comes from cyclone and heat pipe heat exchanger, which combines the advantages of high heat exchange efficiency of heat pipe heat exchanger and good dust removal effect of cyclone.Heat exchange equipment for low temperature waste heat recovery needs to have some unique performance requirements.It can provide better choice for waste heat utilization of cement plant
Xanthohumol inhibits PRRSV proliferation and alleviates oxidative stress induced by PRRSV via the Nrf2–HMOX1 axis
International audiencePorcine reproductive and respiratory syndrome virus (PRRSV) is a prevalent and endemic swine pathogen that causes significant economic losses in the global swine industry. Commercial vaccines provide limited protection against this virus, and no highly effective therapeutic drugs are yet available. In this study, we first screened a library of 386 natural products and found that xanthohumol (Xn), a prenylated flavonoid found in hops, displayed high anti-PRRSV activity by inhibiting PRRSV adsorption onto and internalization into cells. Transcriptome sequencing revealed that Xn treatment stimulates genes associated with the antioxidant response in the nuclear factor-erythroid 2-related factor 2 (Nrf2) signalling pathway. Xn causes increased expression of Nrf2, HMOX1, GCLC, GCLM, and NQO1 in Marc-145 cells. The action of Xn against PRRSV proliferation depends on Nrf2 in Marc-145 cells and porcine alveolar macrophages (PAMs). This finding suggests that Xn significantly inhibits PRRSV proliferation and decreases viral-induced oxidative stress by activating the Nrf2–HMOX1 pathway. This information should be helpful for developing a novel prophylactic and therapeutic strategy against PRRSV infection
Effect of tenofovir disoproxil and telbivudine on the growth and development of infants by blocking mother-to-child transmission of hepatitis B virus
Purpose: To investigate the effect of tenofovir disoproxil and telbivudine on the growth and development of infants after blocking mother-to-child transmission (MTCT) of hepatitis B virus (HBV).
Methods: Seventy pregnant women with chronic hepatitis B (CHB) were recruited and allocated to tenofovir disoproxil group (n = 35) and telbivudine group (n = 35) using random number table method. Tenofovir disoproxil group was given 300 mg tenofovir disoproxil orally four times daily, while telbivudine group was given telbivudine 600 mg orally four times daily.
Results: After treatment, both groups showed no significant differences in serum HBV-DNA and ALT levels before delivery and 3 months after delivery (p > 0.05). Both groups showed no remarkable differences in the incidence of hypohydramnios, cholestasis, hypothyroidism, anemia, prolonged labor, fetal distress, and placental adhesions (p > 0.05). Both groups showed no significant differences in the rates of premature rupture of membranes, preterm birth, vaginal delivery, and cesarean section (p > 0.05). Both groups showed no significant differences in neonatal sex, gestational age at birth, weight, length, and Apgar scores (p > 0.05). The differences in the positive rates of HBVsAg, HBsAb, and HBeAg at birth and at 12 months were not statistically noticeable (p > 0.05).
Conclusion: Tenofovir disoproxil and telbivudine reduce HBV-DNA levels, effectively blocks MTCT, and have a similar safety profile for infants. Further investigations to confirm t
Carbon emission performance evaluation and allocation in Chinese cities
This paper presents a DEA approach with multiple abatement factors to evaluate CO2 emission performance and allocate CO2 emission quotas in Chinese cities. We first consider the difference of marginal abatement costs among cities, and construct the non-radial directional distance function with multiple abatement factors. The total-factor CO2 emission performance index and its dynamic change index are then proposed to measure CO2 emission performance. Considering equity and efficiency, we develop a composite index by the hybrid method to allocate emissions quota, which considers CO2 emissions as well as CO2 emission performance. Then we conduct an empirical study using inputs and outputs dataset of 71 Chinese cities in 2005–2012. Chinese cities have poor energy efficiency and still have high CO2 emissions. The eastern region outperforms the central region and the western region performs worst, whereas the dynamic CO2 emission performance of the central region has the largest increase. The change of CO2 emission performance is driven mainly by technological advances. As for the CO2 emission allocation, the composite index method encourages cities to reduce emissions and enhance emission performance through carbon trading market. It also motivates cities with high historical emissions to reduce their emissions by improving technology when they have poor CO2 emission performance
DEA models with Russell measures
In real applications, data envelopment analysis (DEA) models with Russell measures are widely used although their theoretical studies are scattered over the literature. They often have seemingly similar structures but play very different roles in performance evaluation. In this work, we systematically examine some of the models from the viewpoint of preferences used in their Production Possibility Sets (PPS). We identify their key differences through the convexity and free-disposability of their PPS. We believe that this study will provide guidelines for the correct use of these models. Two empirical cases are used to compare their differences
Time-Consistent Strategies for Multi-Period Portfolio Optimization with/without the Risk-Free Asset
The pre-commitment and time-consistent strategies are the two most representative investment strategies for the classic multi-period mean-variance portfolio selection problem. In this paper, we revisit the case in which there exists one risk-free asset in the market and prove that the time-consistent solution is equivalent to the optimal open-loop solution for the classic multi-period mean-variance model. Then, we further derive the explicit time-consistent solution for the classic multi-period mean-variance model only with risky assets, by constructing a novel Lagrange function and using backward induction. Also, we prove that the Sharpe ratio with both risky and risk-free assets strictly dominates that of only with risky assets under the time-consistent strategy setting. After the theoretical investigation, we perform extensive numerical simulations and out-of-sample tests to compare the performance of pre-commitment and time-consistent strategies. The empirical studies shed light on the important question: what is the primary motivation of using the time-consistent investment strategy
Performance Evaluation of Portfolios with Margin Requirements
In financial markets, short sellers will be required to post margin to cover possible losses in case the prices of the risky assets go up. Only a few studies focus on the optimization and performance evaluation of portfolios in the presence of margin requirements. In this paper, we investigate the theoretical foundation of DEA (data envelopment analysis) approach to evaluate the performance of portfolios with margin requirements from a different perspective. Under the mean-variance framework, we construct the optimization model and portfolio possibility set on considering margin requirements. The convexity of the portfolio possibility set is proved and the concept of efficiency in classical economics is extended to the portfolio case. The DEA models are then developed to evaluate the performance of portfolios with margin requirements. Through the simulations carried out in the end, we show that, with adequate portfolios, DEA can be used as an effective tool in computing the efficiencies of portfolios with margin requirements for the performance evaluation purpose. This study can be viewed as a justification of DEA into performance evaluation of portfolios with margin requirements
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