热轧除鳞系统节能方案

针对热轧除鳞系统普遍存在的能源浪费严重的问题,设计了基于预测模型的变频节能方案,通过板坯位置预测、除鳞时间预测、除鳞水量预测和除鳞泵转速控制,合理利用轧制间歇时间使水泵电机变频降速,模拟计算结果表明,可使除鳞电耗降低23.57%。     

Airborne spread of expiratory droplet nuclei between the occupants of indoor environments: A review

This article reviews past studies of airborne transmission between occupants in indoor environments, focusing on the spread of expiratory droplet nuclei from mouth/nose to mouth/nose for non‐specific diseases. Special attention is paid to summarizing what is known about the influential factors, the inappropriate simplifications of the thermofluid boundary conditions of thermal manikins, the challenges facing the available experimental techniques, and the limitations of available evaluation methods. Secondary issues are highlighted, and some new ways to improve our understanding of airborne transmission indoors are provided. The characteristics of airborne spread of expiratory droplet nuclei between occupants, which are influenced correlatively by both environmental and personal factors, were widely revealed under steady‐state conditions. Owing to the different boundary conditions used, some inconsistent findings on specific influential factors have been published. The available instrumentation was too slow to provide accurate concentration profiles for time‐dependent evaluations of events with obvious time characteristics, while computational fluid dynamics (CFD) studies were mainly performed in the framework of inherently steady Reynolds‐averaged Navier‐Stokes modeling. Future research needs in 3 areas are identified: the importance of the direction of indoor airflow patterns, the dynamics of airborne transmission, and the application of CFD simulations.     

Effects of yoghurt butter oils on rat plasma lipids,haematology and liver histology parameters in a 150‐day study

Although yoghurt butter oil as a fermented dairy product is widely consumed in several countries, its metabolic effects have not been fully elucidated. In this study, male Wistar rats were treated with standard diet, standard diet enriched with 10% or 20% (W/W) of either cow yoghurt butter oil (CYBO), sheep yoghurt butter oil (SYBO) or cottonseed oil (COT) for 20 weeks. Treatment of rats with CYBO or SYBO (at both concentrations) did not significantly influence haematological parameters, plasma lipids and liver histological structure. However, in contrast to popular belief, COT treatment at the higher dose induced leukocytosis, dyslipidaemia and liver steatosis.     

A PV installation framework concerning electricity variable rates

This paper assesses building integrated photovoltaic (BIPV) installation parameters based on the profit generated by a photovoltaic system. It takes into consideration a home building case study and it investigates its monthly energy demand based on a specific location and a typical occupancy. The capability of a photovoltaic (PV) system to generate more profit occurs when solar intensity is maximum while the electric energy price is at its highest rate. The paper traces a framework that encompasses different aspects such as energy demand, energy price, and solar intensity. This framework identifies profit alternatives according to different installation parameters. A tool that predicts a PV installation hourly electric energy production is developed. The profit generated is simulated for home buildings located in Beirut (Lebanon) and Xihua (China), both at 33.8° latitude north. The paper highlights a new approach for BIPV installations, taking into account weather conditions, energy demand, and electric energy utility rates.     

基于峰谷分时电价的虚拟电厂日前申报及运行优化

鉴于分布式能源的出力性质为间歇性和波动性,影响电网安全高效运行,而虚拟电厂可解决此问题。对虚拟电厂进行申报-调度两阶段建模,以包含分布式电源(光电、风电和燃气轮机)和储能系统(储能电池)两大类分布式能源的虚拟电厂为例,基于光照强度及风速等不确定因素,研究峰谷分时电价下日前市场虚拟电厂的出力申报和运行调度策略并利用风险价值模型进行风险管理。结果表明,申报出力时,当电价激励足够高时储能电池方会参与出力,成功起到削峰填谷的作用;运行调度时,平衡出力偏差方面,储能电池发挥主要作用,且虚拟电厂运行调度策略具有一定的经济效益。     

Predicting Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) populations and associated grain damage in smallholder farmers’ maize stores: A machine learning approach

Prostephanus truncatus is a notorious pest of stored-maize grain and its spread throughout sub-Saharan Africa has led to increased levels of grain storage losses. The current study developed models to predict the level of P. truncatus infestation and associated damage of maize grain in smallholder farmer stores. Data were gathered from grain storage trials conducted in Hwedza and Mbire districts of Zimbabwe and correlated with weather data for each site. Insect counts of P. truncatus and other common stored grain insect pests had a strong correlation with time of year with highest recorded numbers from January to May. Correlation analysis showed insect-generated grain dust from boring and feeding activity to be the best indicator of P. truncatus presence in stores (r = 0.70), while a moderate correlation (r = 0.48) was found between P. truncatus numbers and storage insect parasitic wasps, and grain damage levels significantly correlated with the presence of Tribolium castaneum (r = 0.60). Models were developed for predicting P. truncatus infestation and grain damage using parameter selection algorithms and decision-tree machine learning algorithms with 10-fold cross-validation. The P. truncatus population size prediction model performance was weak (r = 0.43) due to the complicated sampling and detection of the pest and eight-week long period between sampling events. The grain damage prediction model had a stronger correlation coefficient (r = 0.93) and is a good estimator for in situ stored grain insect damage. The models were developed for use under southern African climatic conditions and can be improved with more input data to create more precise models for building decision-support tools for smallholder maize-based production systems.     

计及风险规避的电力零售商平衡市场交易模型

由于新能源出力以及终端负荷需求的不确定性,电力零售商在日前市场的竞标电量与实时市场的购买电量之间存在不平衡而产生惩罚成本风险。引入用户侧可控负荷作为平衡资源参与市场交易,提出了一种风险规避程度指标,以此来度量交易前后电量偏差程度,以信息熵度量残差序列离散程度计算风险规避程度指标。以电力零售商运行收益、用户需求响应满意度以及风险规避程度最大为目标建立多目标风险规避模型,采用自适应权重粒子群算法进行模型求解。通过算例表明,所提出的模型从电网-电力零售商-用户多个角度去考虑电力零售商参与平衡市场交易策略,能够有效提高电力零售商的运行效益以及用户满意度,同时可以提高电力市场管理的可靠性与安全性。     

基于P波模量的原位胶结充填体强度预测模型研究

原位胶结充填体质量评价通常采用单轴抗压强度作为表征指标,由于在现场工程中无法快速、准确获取充填体的强度值,因此需要建立一种参数易于获取且准确的原位胶结充填体强度预测模型。基于胶结充填体物理力学参数的内在联系,从量纲平衡的角度探索了胶结充填体单轴抗压强度与P波模量的关系。根据C矿和I矿两种原位胶结充填体的密度、P波速度及取芯强度的测试数据,采用线性拟合的方法获得了基于P波模量的原位胶结充填体强度预测模型。通过对C矿和I矿的强度预测模型拟合效果分析可知,P波模量与取芯强度呈正相关性,且拟合效果较好,证明原位胶结充填体强度预测模型精度高,具有很强的实用性。     

地勘单位转制后税务风险识别与控制

结合“减税降费”的政策背景,以陕西省某转制地勘单位为例,引入风险控制相关理论并应用层次分析法,构建了税务风险评估指标体系,对转制地勘单位面临的税务风险进行了识别、分析、评估。研究结果表明:针对不同的税收类型,应着重关注不同方面的风险,排序前6位的风险依次为企业所得税扣除类风险、增值税决策环节风险、增值税销售环节风险、房产税计税依据风险、企业所得税税收优惠类风险、增值税采购环节风险;并对上述风险的控制机制进行了分析,从企业管控、政策优化两方面分别提出了相关对策和建议。     

基于信息熵—集对分析的煤矿隐患排查治理风险评估模型

以煤矿安全隐患排查治理风险为研究对象，分析隐患排查闭环管理全过程，并基于此建立了隐患排查治理能力纵向评估指标体系，融合熵值法和集对分析理论，建立了煤矿安全隐患排查治理风险纵向评估模型，为企业更好地了解自身隐患排查治理能力及变化发展趋势提供参考，最后进行了实例分析。