Anaerobic digestion of corn silage on a commercial scale: Differential utilization of its chemical constituents and characterization of the solid digestate

The utilization of different chemical constituents of corn silage during industrial-scale anaerobic digestion was determined. Corn silage together with the resulting solid digestate generated during biogas production were collected from an industrial plant during a regular operating period. Moisture, water and ethanol extractives, ash, total nitrogen, starch, cellulose, the monomeric composition of hemicellulose, acid soluble and acid insoluble lignin were measured in both corn silage and corn silage solid digestate. The relative consumption of each component of corn silage during its anaerobic digestion was estimated with reference to acid insoluble lignin. It was assumed that lignin was not digested throughout the process. Starch and large fractions of extractives and acid soluble lignin were digested. In contrast, the digestion of cellulose and particularly hemicellulose were limited (40% and 29% respectively). Of the hemicellulose monomers, xylose was the least digested (20%). The present work shows that the digestate produced by commercial corn-silage anaerobic digestion contains a notable quantity of cell wall polymers. These could potentially be used in biorefinery processes, e.g. ethanol and xylo-oligosaccharide production.     

无熟料水泥混凝土的水化热与干燥收缩

无熟料水泥混凝土(NSC)是以水淬高炉矿渣(GBFS)和激发剂的混合物作为胶凝材料所配制的新型混凝土,其性能取决于GBFS的碱度、化学成分、玻璃化率以及激发剂的种类和数量。为此,以石膏作为GBFS的激发剂来配制NSC后,采用与普通水泥混凝土(简称OPC)对比的方法,进行了NSC的水化热和干燥收缩实验。结果表明,NSC的水化热远小于普通混凝土(OPC);NSC的早期干燥收缩率略大于于OPC,但可用调节水灰比或延长水中养护的方法来减少其干燥收缩。     

SENSC: 一个稳定高效的非负稀疏编码算法

非负稀疏编码(Nonnegative sparse coding, NSC)已成功应用在很多领域的研究中. 目前使用的NSC算法通过梯度投影法和基于辅助函数的乘性更新法相结合来实现, 其性能受迭代步长的影响很大, 且效率较低. 为增强NSC的可应用性, 本文通过对一组凸超抛物面函数做交替最小化来实现NSC, 并依据凸超抛物面特性、点到非负数集合的投影规则以及点到原点处单位超球的投影规则构造了一个无用户定义优化参数的稳定高效的NSC算法---SENSC. 从数学角度, 文中推断了SENSC比现有算法高效且它的解优于当前算法的解, 证明了它的稳定性和收敛性. 实验验证了上述理论推断的正确, 说明了SENSC调节编码稀疏性的能力比已有算法更强.     

无熟料矿渣水泥混凝土对Cl~-的抗渗及固化特性

无熟料水泥混凝土(NSC)是利用水淬高炉矿渣和激发剂在常温下经配料、研磨而成的新型水泥来配制的混凝土,其性能取决于水淬高炉矿渣的碱度、化学成分、玻璃化率以及激发剂的种类和数量,因而对Cl-的抗渗和固化有其独特的性能。为此,以石膏和石灰作为激发剂配制NSC后,用电通量法等科学手段进行了对Cl-离子的抗渗和固化实验。结果表明:NSC的效果远远超过普通混凝土和矿渣水泥。     

清洁的炼铜工艺

本文简要介绍了世界上各种处理硫化铜矿的新型湿法炼铜工艺的发展现状及其日益看好的应用价值。     

POX和NSC研究进展

POX氧压氧化辉钼矿精矿工艺可用于生产工业氧化钼;从低品位钼精矿生产纯三氧化钼;生产高溶性氧化钼;钼精矿除铜和从废催化剂中回收钼和镍等.POX工艺过程环境友好,钼回收率较高.NSC氮氧化物催化压力浸出低品位钼精矿温度低、压力低、作业费用低,硫化钼转入溶液硫呈元素硫存在,研究进展十分引人注目.     

NSC技术在宝钢铁钢快速分析计算机系统中的应用

作为一种构建高可靠、永不间断系统的关键技术,NonStop在关键应用领域得到广泛运用。宝钢检化验快速分析计算机在工业标准服务器上应用NSC技术,构建出了一套满足实时应用的高可靠性、高性价比的过程控制计算机系统。     

Operation and control of a DFIG-based grid-connected WECS using NSC during grid fault and with unbalanced non-linear load

This paper proposes a combined feed-forward and selective harmonic compensation-based control scheme for a grid-connected doubly fed induction generator Wind Turbine system using a nine-switch converter (NSC) to improve the performance during grid faults and unbalanced non-linear loading. This is achieved through desired line voltage compensation and/or selective harmonic reduction technique. The two outputs of NSC are controlled such that one functions as a series grid-side converter to inject appropriate voltage in series with stator terminals to maintain the desired stator voltage profile, while the other one functions as a parallel grid-side converter to regulate the DC-link voltage to its reference value irrespective of the direction of flow of rotor power with the conventional rotor side converter. Simulation has been carried out in a MATLAB/Simulink environment. The results show that the proposed scheme ensures the feasibility of improving the Fault Ride Through capability and reducing the undesirable effects of the unbalanced, harmonic content in grid voltage at the Point of Common Coupling.     

Modified expression for predicting the bending resistance of a locally corroded pipeline and its experimental verification

In practical service, transmitted pipelines may suffer from corrosion, which affects the safety of the component. For an engineering pipeline subjected to local corrosion, the pipe wall becomes thinner locally, and the bending load bearing capacity is inevitably reduced. Therefore, proper prediction of the bending resistance of a pipeline with locally corroded defects is very significant with respect to the safety assessement of a servicing pipeline. In the present paper, the effect of the length of local thinning in a pipe in the longitudinal direction is considered. A modification to the net-section collapse failure (NSC) criterion is then proposed. 3-point bending experiments for J55 pipe with artificially machined local thinning on the outer-surface of the pipe are conducted to verify the modified expression. Comparison of the predictions of the modified NSC with the experimental data indicates that the modified expression can predict the general variation tendency of the normalized bending resistance (M/M0) with the relative longitudinal defect lenght (). However, discrepancy between the theoretical prediction and experimental data is apparent for a small relative longitudinal defect leght ( to 3). This discrepancy might result from the stress concentration effect, which has not been considered in the model.     

关于NS3中GRE仿真的研究

研究如何在NS3这款网络仿真软件上模拟GRE这种VPN协议.首先对GRE协议作了简介,再初步介绍了NS3仿真软件,并把它与它的前辈NS2作了对比.然后,展示了如何在真实网络环境下配置GRE协议,并以此作为研究成功与否的衡量标准.接着,从NS3中的NSC组件出发,发现可以利用NS3中的Tap NetDevice模块来实现...