Developing Cost Response Models for Company-Level Cost Flow Forecasting of Project-Based Corporations

The difficulty in applying the standard curve (S-curve) and cost-schedule integration (CSI) techniques for company-level cost flow forecasting in a project-based industry is the prerequisite of forecasting future unknown individual projects and contract classifications. By analyzing cost flows at the company level through a pool of macroeconomic and internal financial data, this paper proposes an innovative approach to firm-specific model estimation. First, a series of data transformations introduce linear relationships between cost, macroeconomic, and internal financial variables. Second, multivariate regression analysis is employed for initial model building. Third, for the purposes of model restructuring, a subsequent application of Yule–Walker estimates and incomplete principal component analysis is used. This paper uses a sample of four project-based construction firms to demonstrate model performance. Using this methodology, mean absolute percentage error (MAPE) values of the forecasting models range from 0.27 to 0.60%. As such, the transformed cost, macroeconomic, internal financial data could strongly predict company-level cost flow forecasting. While converting the predicted cumulative cost data to periodic cost flows, the MAPE values were augmented, ranging from 7.04 to 17.55%, thus, requiring future research.     

催化重整装置的扩能改造

介绍湛江东兴炼油厂的重整装置由200kt／a扩能至300kt／a中有关催化重整反应动力学模拟计算软件的应用、反应工艺技术的改造、装置标定的情况。结合装置实际情况，采用两段装填、两段混氢技术提升了装置的技术水平。标定结果表明，改造后的装置达到了预期目的。     

井冈山水厂设计体会

阐述水厂设计中对水厂规模、水源地、净水厂位置及净水工艺的确定过程，根据原水的特点，通过分析对无阀滤池进行改良。     

Effect of Y2O3, CeO2 on Sintering Properties of Si3N4 Ceramics

The effect of rare earth oxides Y203 or Ce02 on sintering properties of Si3N4 ceramics was studied and the mechanism of assisting action during sintering was analyzed. The results in dicate that the best sintering properties appear in Si3N4 ceramics with 5% Y203 or 8% CeO2. Secondary crystallites are formed at grain boundaries after heat treatment,which decreases the amount of glass phase and contributes to the improvement of high-temperature mechanical properties of silicon nitride.     

Experience in testing the Motif interface

The testing and quality assurance of the Motif 1.0 graphical user-interface software are described. The testing goals, which fell into three general categories (code coverage, defect-density, and defect-arrival rate), and a deliverable formal test suite are examined. The three phases of the testing process-evaluation, test development, and regression testing-and the tools used in testing are discussed     

Ozonation of CI Reactive Black 5 using rotating packed bed and stirred tank reactor

This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry     

Crystal growth of selected II–VI semiconducting alloys by directional solidification: Part I Ground-based experiments

A series of Hg_0.84Zn_0.16 Te crystal ingots have been grown from pseudobinary melts by the Bridgmam–Stockbarger type directional solidification using a Marshall Space Flight Center/Space Science Laboratory heat-pipe furnace and the ground control experiment laboratory furnace of the crystal growth furnace which was flown on the first United States Microgravity Mission. A number of translation rates and a series of hot- and cold-zone temperatures were employed to assess the influence of growth parameters on the crystal properties for the purpose of optimizing the in-flight growth conditions. This revised version was published online in November 2006 with corrections to the Cover Date.     

煤气吹扫时惰性气体抑爆用量的优选

运用惰性气体消防抑爆理论，采用数学积分法计算出吹扫煤气设施时抑爆所需最少惰性气体需要量．     

A MULTIAXIAL FATIGUE DAMAGE MODEL FOR ORTHOTROPIC MATERIALS UNDER PROPORTIONAL LOADING

A new multiaxial fatigue damage model for orthotropic materials is proposed based on the strain vector. Six material constants are included in the model. These material constants represent the dependence of fatigue resistance on material orientation, and they can be obtained by conducting strain-controlled uniaxial fatigue tests along the three principal orthotropic directions of an orthotropic material. The model can also be transformed in new coordinate systems to predict the fatigue lives of new material orientations. Biaxial low-cycle fatigue tests are conducted to verify the model. The prediction of the model agrees with the experimental results reasonably well.     

Study and design of step-index channel waveguide bends withlarge-angle and low-loss characteristics

By using micro-prisms, improved three-dimensional (3-D) bends of the embedded and buried waveguides of step-index profile are proposed. A simple phase compensation rule for the optimal design of the micro-prism is also presented. Through the simulation of 3-D semivectorial finite-difference beam propagation method, the transmission characteristics of the improved bends are shown to have been enhanced dramatically as compared with those of the conventional ones. Even for a bend angle of as large as 10°, the normalized transmitted power can still be greater than 95%. These results of 3-D bends are then compared with those of the two-dimensional (2-D) ones which are simplified from 3-D structures by the effective index method, and physical explanation of the discrepancy between the 3-D and 2-D results is introduced. The influences of waveguide structures and prism parameters on the transmission characteristics are discussed in detail. Some criteria for the design of large-angle low-loss 3-D improved bends are also accessed