Environmental and economic assessment of producing hydroprocessed jet and diesel fuel from waste oils and tallow

Animal fats and waste oils are potential feedstocks for producing hydroprocessed esters and fatty acids (HEFA) jet and diesel fuels. This paper calculates the lifecycle greenhouse gas (GHG) emissions and production costs associated with HEFA jet and diesel fuels from tallow, and from yellow grease (YG) derived from used cooking oil. For YG, total CO₂ equivalent (CO₂ eq.) GHG emissions of jet and diesel were found to range between 16.8–21.4 g MJ⁻¹ and 12.2–16.9 g MJ⁻¹ respectively. This corresponds to lifecycle GHG emission reductions of 76–81% and 81–86% respectively, compared to their conventional counterparts. Two different system boundaries were considered for tallow-derived HEFA fuels. In System 1 (S1), tallow was treated as a by-product of the rendering industry, and emissions from rendering and fuel production were included. In System 2 (S2), tallow was considered as a by-product of the meat production industry, and in addition to the S1 emissions, cattle husbandry and slaughtering were also included. The lifecycle emissions (CO₂ eq.) from HEFA jet fuel for S1 and S2 were estimated to be 25.7–37.5 g MJ⁻¹ and 67.1–83.9 g MJ⁻¹ respectively. HEFA diesel lifecycle emissions were found to be 21.3–33.3 g MJ⁻¹ for S1 and 63.4–80.5 g MJ⁻¹ for S2. Production costs for these fuels were calculated using a discounted cash flow rate of return model. The minimum selling price was estimated to be 880 $ m⁻³–1060 $ m⁻³ for YG-derived HEFA, and 1050–1250 $ m⁻³ for tallow-derived HEFA fuels.     

建立动态的网络信息安全防护体系

本文阐述了网络信息安全防护的动态表现，并给出了两个动态的网络信息安全解决方案，信息安全生命周期模糊和网络安全三维立体模型。     

Real-world effectiveness of Ergonomic methods

The way ahead with the practical development and application of Ergonomic methods is through a better anticipation and appreciation of changes to system effectiveness and human work that will be incurred through the introduction of new technologies to the workplace. These improvements will involve an improved awareness by the system of the working context and environment. The argued future is with improvements in the handling and use of knowledge by systems. The development of suitable Ergonomics methods, or the careful adaptation of existing methods, should accompany any technological revolution. Moreover, future methods are needed that are specifically developed to be applicable to the real time study of work considering both work context and the amalgamation of results from the use of many diverse methods throughout the design and development life cycle of a system. Part of this process will be a necessary complementation of both quantitative and qualitative methods and guidelines. Another focus should be on creating improved Ergonomics participation within multidisciplinary system design and development environments throughout the system's life cycle. Only through this avenue can Ergonomics show a consistent and valued contribution to quality design and its development. In parallel to such a contribution will be an acceptance by other engineering disciplines, managers, and customers that such an application of Ergonomics is cost effective.     

A lifecycle-based indicator to support residual solid waste flow planning at the regional level

Managing waste and promoting a transition to a resource-efficient economy are key elements of the European environmental policy. This research aims to explore waste transport's environmental relevance and assess how to operationalize inter-territorial cooperation for waste management.This study develops a lifecycle-based indicator to analyze and compare three alternative scenarios for residual waste flow planning. Results indicate that the incidence of transport is relevant to the point that, if not considered, it can lead to ineffective decisions.     

Trends in bioconversion of lignocellulose: Biofuels,platform chemicals & biorefinery concept

Bioconversion of renewable lignocellulosic biomass to biofuel and value added products are globally gaining significant prominence. Market forces demonstrate a drive towards products benign to natural environment increasing the importance of renewable materials. The development of second generation bioethanol from lignocellulosic biomass serves many advantages from both energy and environmental point of views. Biomass an inexpensive feedstock considered sustainable and renewable, is an option with the potential to replace a wide diversity of fossil based products within the energy sector; heat, power, fuels, materials and chemicals. Lignocellulose is a major structural component of woody and non-woody plants and consists of cellulose, hemicellulose and lignin. The effective utilization of all the three components would play a significant role in the economic viability of cellulosic ethanol. Biomass conversion process involves five major steps, choice of suitable biomass, effective pretreatment, production of saccharolytic enzymes-cellulases and hemicellulases, fermentation of hexoses and pentoses and downstream processing. Within the context of production of fuels from biomass, pretreatment has come to denote processes by which cellulosic biomass is made amenable to the action of hydrolytic enzymes. The limited effectiveness of current enzymatic process on lignocellulose is thought to be due to the relative difficulties in pretreating the feedstocks. The present review is a comprehensive state of the art describing the advancement in recent pretreaments, metabolic engineering approaches with special emphasis on the latest developments in consolidated biomass processing, current global scenario of bioethanol pilot plants and biorefinery concept for the production of biofuels and bioproducts.     

基于HLA的仿真程序设计研究

高层体系结构HLA以其突出的互操作性和可重用性,成为当今分布式交互仿真系统结构标准,研究基于HLA的仿真程序设计方法对于分布式交互仿真系统的开发具有重要意义。该文从联邦创建到联邦退出,以程序设汁的角度,详细地剖析了联邦执行的整个生命周期过程,还分析了联邦执行的整个生命周期中联邦执行的各种状态以及联邦成员、联邦执行、RTI这三者之间的关系。根据联邦执行的生命周期过程,给出了联邦成员的应用程序框架,并且举例说明了HLA仿真程序设计的步骤和一般方法。     

支持产品全生命周期设计的广义装配建模的研究

装配建模的实质就在于如何在计算机内有效地表达装配体外在的和内在的关系。本文在分析装配体几何实体信息模型、配合联接信息及设计约束机制的基础上,提出了一种以层次结构信息为逻辑主干,以拓朴联接信息为重要组成部分、支持产品全生命周期设计的广义装配模型的表达机制。该模型具有在数据结构与设计者的概念模型相同,便于理解,支持自上而下逐步求精的设计过程,便于装配模型根据需要进行修改和扩充,支持产品生命周期设计的全过程等特点。     

一种新的数据质量模型的研究

给出了一个软件系统中数据质量评估和优化的模型CLDQ,该模型的特点是：作用于软件生命周期的全进程;数据质量的评估是可计算的。     

浅析铅酸善电池使用周期的影响因素及对策

充电方法和维护方法直接影响铅酸蓄电池的使用周期,本文对影响蓄电池使用周期的主要因素进行分析,并提出延长铅酸蓄电池的使用周期的具体方法,对铅酸蓄电池的使用维护具有一定的指导意义。     

智慧建设及其支持体系研究

根据我国建筑业发展的实际,基于智慧城市和工程项目全生命周期管理的理念,提出智慧建设的基本概念,阐述智慧建设的主要特性,构建智慧建设的理论和技术支持体系,简要描述智慧建设的发展前景和研究方向。智慧建设将有效地解决我国建筑业信息化程度低、缺乏全生命周期管理理念和手段、传统工程项目管理理论无法适应现代工程项目需要等问题,为我国建筑业的发展提供一种新的路径。