Complexity theory and collaboration: An agent-based simulator for a space mission design team

In this paper, we investigate how complexity theory can benefit collaboration by applying an agent-based computer simulation approach to a new form of synchronous real-time collaborative engineering design. Fieldwork was conducted with a space mission design team during their actual design sessions, to collect data on their group conversations, team interdependencies, and error monitoring and recovery practices. Based on the fieldwork analysis, an agent-based simulator was constructed. The simulation shows how error recovery and monitoring is affected by the number of small group, or sidebar, conversations, and consequent noise in the room environment. This simulation shows that it is possible to create a virtual environment with cooperating agents interacting in a dynamic environment. This simulation approach is useful for identifying the best scenarios and eliminating potential catastrophic combinations of parameters and values, where error recovery and workload in collaborative engineering design could be significantly impacted. This approach is also useful for defining strategies for integrating solutions into organizations. Narjès Bellamine-Ben Saoud is an Associate Professor at the University of Tunis and Researcher at RIADI-GDL Laboratory, Tunisia. After Computer Science engineering diploma (1993) of the ENSEEIHT of Toulouse, France, she received her PhD (1996), on groupware design applied to the study of cooperation within a space project, from the University of Toulouse I, France. Her main research interests concern studying complex systems particularly by modeling and simulating collaborative and socio-technical systems; developing Computer Supported Collaborative Learning in tunisian primary schools; and Software Engineering. Her current reserach projects include modeling and simulation of emergency rescue activities for large-scale accidents, modeling of epidemics and study of malaria, simulation of collabration artifacts. Gloria Mark is an Associate Professor in the Department of Informatics, University of California, Irvine. Dr. Mark received her Ph.D. in Psychology from Columbia University in 1991. Prior to UCI, she was a Research Scientist at the GMD, in Bonn, Germany, a visiting research scientist at the Boeing Company, and a research scientist at the Electronic Data Systems Center for Advanced Research. Dr. Mark’s research focuses on the design and evaluation of collaborative systems. Her current projects include studying worklife in the network-centric organization, multi-tasking of information workers, nomad workers, and a work in a large-scale medical collaboratory. Dr. Mark is widely published in the fields of CSCW and HCI, is currently the program co-chair for the ACM CSCW’06 conference and is on the editorial board of Computer Supported Cooperative Work: The Journal of Collaborative Computing, and e-Service Qu@rterly.     

Validation of an HPLC Method for the Determination of Valdecoxib and its Degradation Product: a Mixture of α- and β-n-Lactosyl Sulfonamide Anomers

An HPLC method has been developed for the separation of valdecoxib and a degradation product consisting of α and β-N-lactosyl sulfonamide, i.e. α and β anomers (SC-77852). Best results were achieved with a Chromolith Performance RP-18e column (100 mm × 4.6 mm), macropore size 2 μm, mesopore size 13 nm, with an eluent of methanol:water containing a 1% solution of TEA (36:64 v/v), pH 7.4 (adjusted with 85% orthophosphoric acid), at 22 °C. Detection was at 220 nm. The method was validated for its selectivity, linearity, precision (repeatability) and robustness. Quantitation and detection limits were determined for both valdecoxib and SC-77852. Method robustness was further evaluated by performing 2³ full factorial design experiments. The final step, optimisation of the variables, was performed using response surface design. The validated method was used for assay of valdecoxib and SC-77852 in Bextra^® film-coated tablets.     

Deformability of expanded polystyrene under short-term compression

The results obtained in an experimental investigation of deformability of expanded polystyrene (EPS) under short-term compression are presented. The density of EPS varied from 13 to 28 kg/m³. The method of design of experiments was used to determine the elastic modulus and the ultimate strain (corresponding to the end of quasi-linear deformability) under compression stresses operating perpendicularly and parallel to the faces of EPS products. A graphical interpretation of the models is also presented. Based on the experimental data obtained, it was concluded that the expanded polystyrene was homogeneous in mutually perpendicular planes with respect to its deformability in compression. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 5, pp. 639–656, September–October, 2007.     

PET/SiO2 nanocomposites prepared by cryomilling

The mixed powders of poly(ethylene terephthalate) (PET) and SiO₂ has been subjected to cryomilling. The evolution of microstructure with time was characterized using scanning electron microscope, transmission electron microscope, field emission scanning electron microscope, and laser diffraction particle size analyzer. It was shown that, upon cryomilling for 10 h, SiO₂ nano particles were well deconglomerated into single particles (～30 nm) that get homogeneously dispersed in PET matrix. The resulted PET/SiO₂ primary particles were flake‐shaped with a size of 400 nm. These primary composite particles agglomerated to form secondary composite particles with an average size about 7.6 μm. A three‐stage model was purposed for the formation mechanism of the nanocomposite structures induced by cryomilling. Our evidences suggest that cryomilling is a capable and promising technique for the production of polymer/inorganic nanocomposites. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1161–1167, 2006     

Applying the finite-thickness model to designs of cylindrical microlenses with small -numbers

The finite-thickness model (FTM) is applied to the design of cylindrical microlenses based on the wave-front interference principle, rather than the existing zero-thickness model (ZTM). This design method is very simple in physics and highly efficient in computations. For cylindrical lenses with different f-numbers (from f/1.5 to f/0.6), the detailed designs by using both the FTM and the ZTM are carried out. To show the superiority of the FTM to the ZTM, we investigate the focal performance of all the designed lenses based on rigorous electromagnetic theory and the boundary element method. Numerical results reveal that the constructed cylindrical lenses by the FTM are witnessed to exhibit much better focusing performance than those by the ZTM, especially for the small f-numbers.     

High-accuracy surface position sensor based on a two-lens system

Two optical lenses are used to compose a surface position measuring system. A measurand is positioned near the front focal point of the first lens. At the output end of the other lens, a beam splitter is used to split the beam into two paths. One photodetector is positioned before the focal point of the lens in one path and another after the focal point in the other so that the intensities falling onto the two detectors can be adjusted to be equal when the first lens is in focus. This device provides a compact and high-accuracy surface sensor. In this paper, the design and experimental study of the sensor system is described. It is shown that such a sensor embodiment can lead to a resolution of 1 μm.     

短周期涡轮实验台快速阀设计计算及试验分析

本文介绍了短周期涡轮实验台关键设备之——快速阀的工作原理,建立了数学模型和计算方法,进行了设计性能计算。分别在大气和真空条件下对快速阀进行了调试和测量,并对计算和实验结果进行了分析。     

实验和数值模拟超导绕组的机械特性

为了减少环氧浸渍的超导磁体的锻炼和退化效应，基于实验和数值模拟研究了在热应力的电磁力的条件下超导绕组的机械特性；研究的基本目的是决定超导复合线圈基本的材料特性，其中复合超导绕组的杨氏模量和热收缩系数是基本的参数，使用这些参数我们可以用有限元方法精确地研究超导磁体的机械特性，通过分析各种超导磁体的设计，判断好的和坏的磁体设计，从而发展新的超导磁体的设计标准，形成超导磁体的设计和建造的基本方法，本中我们将通过实验和FEA模拟研究复合绕组的基本参数和应用特性。     

离心泵叶轮轴面流道计算新方法

现有的两类一元理论离心泵叶轮水力设计方法存在试凑性工作量大或盖板形状不为简单曲线的缺陷。本文提出了符合一元理论的离心泵叶轮轴面流道过流断面的一种新的分布规律,并给出了按照此分布规律计算叶轮轴面流道过流面积的计算方法和公式。将其与传统的两类设计方法做了比较。