泵—装置运行的心脏处理得当，可让您夜间安然入睡

在现代硫酸装置中，干吸工段的转动设备很少-1～3台干吸塔循环酸泵、一台排酸泵-仅此而己。在路易斯公司，我们强调主循环泵的重要性，把它们称之为“装置运行的心脏”。一年350天，这些泵日复一日地驱动着热浓硫酸，流经管道、阀门和酸冷却器，穿越分酸系统和干吸塔，循环不息。对于密度为1.8g/cm^3的硫酸，我们选择合适的耐腐蚀材料和坚固的机械结构，以保证泵能够无故障运行。只要采取适当的操作和维护技术，泵很容易从一次大修运行至另一次大修。本文介绍干吸系统循环泵的常见故障及其原因，提出预防事故的建议。     

谁动了我的格子间

曾经，在工业化国家，标准的工作场所是堆放着又脏又吵机器的工厂；而今天，这个场所变成了办公室。全球有数以亿计的人在办公桌前工作着，有的被隔板分离，有的没有。     

新一代天然纤维——牛角瓜绒

近年来,天然纤维凭借其良好的生物相容性、可生物降解性、生产加工无毒无害,以及产量丰富等优点,在各技术和商业领域得到了广泛的应用。棉纤维从一开始就是制造服装的首选原料。虽然现在人们发明了各种合成纤维、人造纤维,但仍没有找到合适的原料替代棉纤维。牛角瓜绒是一种植物的种子纤维,其具有与木棉纤维相似的外观,以及很多优良的性能,可作为棉纤维的替代品。对牛角瓜绒的植物来源、特点、可纺性、机械性能及吸湿性进行了介绍。     

Excel/亚麻混纺织物的织造及后处理

天然韧皮纤维(亚麻)具有很好的手感、舒适性,以及独特的风格,很受消费者青睐。传统上亚麻用于生产相对简单的机织物(床单)或非常复杂的织物(如花缎)。亚麻的工业用途包括过滤布和帆布。过去几十年里,机织行业一直朝着扩大使用范围和提高设计灵活性方面发展,这一发展趋势与亚麻在服装市场上的广泛应用是一致的,因为服装市场比传统市场更需要时尚元素。100%的亚麻制品织造困难,而且产品的成本非常高。为解决这一问题,尝试将亚麻与棉、聚酯和其他纤维素纤维混纺后进行织造。介绍了Excel和亚麻混纺纱进行织造和湿处理加工所需的重要的生产控制。选择Excel和亚麻混合是因为它能改善亚麻织物的外观,提高舒适性、染色性和悬垂性。     

注水开发含有中质／重质油砂岩储层有利于加密钻井的条件

调查了四个注水开发项目（各有几口加密井）的生产史来确定含有重质／中质油的砂岩储层中有利于加密钻井的条件。根据新、老加密井的动态来推导储层非均质性的控制作用。由于这些非均质性，老的井不能泄出储层内含有的一些可动油，而加密井能够泄出一部分（最高可达25％）这类油。基于研究的案例，有利于加密井的条件是： a）老井的目前产油量大于3立方米／日，含水量小于75％。 b）缩小井距的原始石油地质储量（OOIP）大于80000立方米／井，总采收率（一次＋注水开发）大于25％。 建议通过进一步技术和经济研究来验证这些标准。     

Tea and coffee consumption in relation to vitamin D and calcium levels in Saudi adolescents

ABSTRACT: BACKGROUND: Coffee and tea consumption was hypothesized to interact with variants of vitamin D-receptor polymorphisms, but limited evidence exists. Here we determine for the first time whether increased coffee and tea consumption affects circulating levels of 25-hydroxyvitamin D in a cohort of Saudi adolescents. METHODS: A total of 330 randomly selected Saudi adolescents were included. Anthropometrics were recorded and fasting blood samples were analyzed for routine analysis of fasting glucose, lipid levels, calcium, albumin and phosphorous. Frequency of coffee and tea intake was noted. 25-hydroxyvitamin D levels were measured using enzyme-linked immunosorbent assays. RESULTS: Improved lipid profiles were observed in both boys and girls, as demonstrated by increased levels of HDL-cholesterol, even after controlling for age and BMI, among those consuming 9--12 cups of coffee/week. Vitamin D levels were significantly highest among those consuming 9--12 cups of tea/week in all subjects (p-value 0.009) independent of age, gender, BMI, physical activity and sun exposure. CONCLUSION: This study suggests a link between tea consumption and vitamin D levels in a cohort of Saudi adolescents, independent of age, BMI, gender, physical activity and sun exposure. These findings should be confirmed prospectively.     

POLYELECTROLYTE MULTILAYER STAMPING IN AQUEOUS PHASE AND NON-CONTACT MODE

Polyelectrolyte multilayer (PEM) transfer printing has been previously achieved by stamping under dry conditions. Here, we show for the first time, that PEM can be transferred from a stamp to the base substrate under aqueous conditions whereby the two surfaces are in a non-contact mode. Degradable multilayers of (PAA/PEG)(10.5) followed by non-degradable multilayers of (PDAC/SPS)(80.5) were fabricated under acidic pH conditions on either PDMS or glass (stamp), and subsequently transferred over top of another multilayer prepared on a different substrate (base substrate), with a spacing of ~ 200 μm between the stamping surface and the base substrate. This multilayer transfer was performed under physiological pH conditions. This process is referred to herein as non-contact, aqueous-phase multilayer (NAM) transfer. NAM transfer can be useful for applications such as fabricating three-dimensional (3-D) cellular scaffolds. We attempted to create a 3-D cellular scaffold using NAM transfer, and characterized the scaffolds with conventional and fluorescence microscopy.     

A Physics-driven Neural Networks-based Simulation System (PhyNNeSS) for multimodal interactive virtual environments involving nonlinear deformable objects

BACKGROUND: While an update rate of 30 Hz is considered adequate for real time graphics, a much higher update rate of about 1 kHz is necessary for haptics. Physics-based modeling of deformable objects, especially when large nonlinear deformations and complex nonlinear material properties are involved, at these very high rates is one of the most challenging tasks in the development of real time simulation systems. While some specialized solutions exist, there is no general solution for arbitrary nonlinearities. METHODS: In this work we present PhyNNeSS - a Physics-driven Neural Networks-based Simulation System - to address this long-standing technical challenge. The first step is an off-line pre-computation step in which a database is generated by applying carefully prescribed displacements to each node of the finite element models of the deformable objects. In the next step, the data is condensed into a set of coefficients describing neurons of a Radial Basis Function network (RBFN). During real-time computation, these neural networks are used to reconstruct the deformation fields as well as the interaction forces. RESULTS: We present realistic simulation examples from interactive surgical simulation with real time force feedback. As an example, we have developed a deformable human stomach model and a Penrose-drain model used in the Fundamentals of Laparoscopic Surgery (FLS) training tool box. CONCLUSIONS: A unique computational modeling system has been developed that is capable of simulating the response of nonlinear deformable objects in real time. The method distinguishes itself from previous efforts in that a systematic physics-based pre-computational step allows training of neural networks which may be used in real time simulations. We show, through careful error analysis, that the scheme is scalable, with the accuracy being controlled by the number of neurons used in the simulation. PhyNNeSS has been integrated into SoFMIS (Software Framework for Multimodal Interactive Simulation) for general use.