Computer-aided procedures for subdivision design and evaluation

Design and management of residential subdivisions are described using a case study in Regina, Saskatchewan. Capital, operation and maintenance costs of physical services and fuel costs for intra-subdivision trips are compared for four subdivision layouts using the procedures. The solar superblock layout is the lowest subdivision layout. Future procedures to assist subdivision design engineers and planners are summarized.     

The electronic spreadsheet as a didactic learning enhancement

A variety of quantitative techniques (such as capital budgeting or linear programming) may be understood more fully by students when they are able to work through relatively simple applications of the techniques by hand. Unfortunately, such manual computations are inherently susceptible to arithmetic errors. The authors propose that students use the electronic spreadsheet to work out these types of problems during their initial learning stage. An advantage of the electronic spreadsheet for this purpose is the automatic calculation of data by the program thereby eliminating the usual arithmetic errors. As long as appropriate formulas are correctly entered into the spreadsheet, the results should be correct.The method presented by the authors does not yield general solutions to capital budgeting or to linear programming problems. Rather, the methodology requires the student to think through the solution process while removing some of the usual drudgery and potential inaccuracies of manual solutions.     

An Introduction to Spiral Steroids

In addition to classical steroids, which have cholesterol as a precursor, there are steroids with 7-dehydrocholesterol as a precursor. This review describes the identification of these steroids, their biosynthesis, and some aspects of their function. There are three classes of these compounds, distinguished by the number of their carbon atoms, 23, 24, and 25. Each class has a spiral steroid and is a phosphodiester. Up until these investigations, no spiral steroids or steroid phosphodiesters were known. There are at least 13 compounds, of which six have been purified to near homogeneity; each one has been characterized by its mass and proposed composition, and they function by regulating the NaK-ATPase. Based on the tissues in which they have been detected, each class of compound seems to regulate a different isoform of the NaK-ATPase. This is an important site of endocrine regulation.     

Understanding Viruses Bio-logically

Networks dominate today’s computing landscape and commercial, technical protection is lagging behind attack technology. As a result, protection program success depends more on prudent management decisions than on the selection of technical safeguards. Managing Network Security takes a management view of protection and seeks to reconcile the need for security with the limitations of technology.     

家庭中的无线安全

现在,在看过论坛的大量文章之后,相信您已经对无线LAN(无线局域网,WLAN)采取了敬而远之的态度。至少,您已经对WLAN产生了怀疑——这并不是一件坏事情。Rik描述了Wep的缺陷,Corey描述了如何将无线访问点转移到DMZ中,而Dave指出应该将它们彻底地放到外面。不过,还没有人说应该完全舍弃WLAN,这是出于两个非常有说服力的理由。首先,WLAN在某些场合非常有用;其次,您完全可以不必听我们的。您已经知道WLAN在办公室的用处。但是,它在家里有什么用呢?正如许多人所指出的,“无线”的价格很便宜,而且确实行之有效(我在撰写本文时,就是通过…     

改进缺陷,套刻和聚焦性能的第五世代浸没式曝光系统

论述了第五世代双扫描平台浸液式扫描曝光机的性能和进展。表明了在高速扫描状态下有生产价值的套刻和聚焦性能的实现。浸液式设备更多的关键部分与缺陷有关,而且该机的改进是通过有生产价值的缺陷水平方面来体现的。为了保持这种缺陷水平的改进效果,需要在圆片应用中进行专门稳定的测量。特加是边缘空泡除去(EBR)设计和圆片斜面良流线性是很重要的。     

IPv4/IPv6的共存、过渡与寻址

本文从技术人员的角度对有关IP技术和IP网络的发展前景进行展望.当前的互联网正面临着从传统IPv4协议向IPv6协议的过渡,作者将着重分析过渡需求和主要的技术问题及其当前进展,以及遗留的其他课题.为了实现这一目标,还需要对互联网协议的历史、现状以及未解决的问题进行说明.     

Optimal Beer Fermentation

A new tool was developed to solve a wide range of optimal beer fermentation problems. Using a mathematical model of beer fermentation, the direct dynamic optimization technique of sequential quadratic programming was investigated for determining the optimal cooling policy to maximize ethanol production for a fixed final time, including effects that optimize flavor. The new tool is very efficient for determining optimal cooling strategies. New control strategies were found that increase ethanol production while decreasing the deleterious effects of fusel alcohols and keeping the acetaldehyde concentrations at moderate levels. Model parameter sensitivity was investigated and it was shown that the system could be regulated successfully around optimal temperature profiles.     

Deposition and characterization of low-loss epitaxial non-linear dielectric thin films for microwave devices

Abstract

Oxide ferroelectric thin films for frequency-tunable microwave devices, in which the dielectric constant of the non-linear dielectric is varied by application of electric fields, have been deposited using PLD. We have fabricated single phase epitaxial Ba_0.6Sr_0.4TiO₃ and KTaO₃ thin film capacitors for applications at 300K and 77K, respectively. Single phase KTaO₃ films were obtained only with excess potassium source in the target along with KTaO₃ perovskite phase. The films have been characterized for structure and morphology by X-ray diffraction and AFM. The dielectric properties were measured in the low frequency range from 100 kHz to 10 MHz, using interdigitated capacitors. Low loss tangents (0.002 at 300K) were observed for highly oriented Ba_0.6Sr_0.4TiO₃ films. The importance of low losses for various devices is discussed and the dielectric constants, loss tangents and tunability of these films are reported in this paper.     

The Design of Electromagnetic Flowmeter Probes with Homogeneous Luminal Magnetic Fields

Inhomogeneities in magnetic field density are not very critical in pulsating arterial flow, but may be an important consideration in venous flow and branch or asymmetric flow. In this regard, a blood flow probe design has been developed with a magnetic field distribution which varies less than 1% across the lumen. It is shown that the luminal fields of two commercially available probes vary as much as 25%.