A system for simulation, monitoring and diagnosis of controlled continuous processes with slow dynamics

This paper presents a modelling approach specifically designed to be used in a monitoring and diagnosis system based on the simulation of relevant process and control system variables. The model is based on semantically extended data flow diagrams with each computational process representing the incremental behaviour of a component of the plant to be modelled. Variable as well as delay time behaviour is associated with each component model to support an event-driven simulation which, in turn, reduces computation time. This plant model of independent but interacting computational processes is easily extendable, modifiable and adjustable according to changes in the plant.

The modelling approach is applied to a coal power plant process and is implemented in G2, an object-oriented, real-time expert system shell with built-in simulation and online external connection capabilities. Generic rules guiding the event-driven simulation and monitoring allow for modular adaptation of the model as the plant's structure and functionality change without requiring changes in the rule set.     

Out‐of‐Plane 3D‐Printed Microfibers Improve the Shear Properties of Hydrogel Composites

One challenge in biofabrication is to fabricate a matrix that is soft enough to elicit optimal cell behavior while possessing the strength required to withstand the mechanical load that the matrix is subjected to once implanted in the body. Here, melt electrowriting (MEW) is used to direct‐write poly(ε‐caprolactone) fibers “out‐of‐plane” by design. These out‐of‐plane fibers are specifically intended to stabilize an existing structure and subsequently improve the shear modulus of hydrogel–fiber composites. The stabilizing fibers (diameter = 13.3 ± 0.3 µm) are sinusoidally direct‐written over an existing MEW wall‐like structure (330 µm height). The printed constructs are embedded in different hydrogels (5, 10, and 15 wt% polyacrylamide; 65% poly(2‐hydroxyethyl methacrylate) (pHEMA)) and a frequency sweep test (0.05–500 rad s^?1, 0.01% strain, n = 5) is performed to measure the complex shear modulus. For the rheological measurements, stabilizing fibers are deposited with a radial‐architecture prior to embedding to correspond to the direction of the stabilizing fibers with the loading of the rheometer. Stabilizing fibers increase the complex shear modulus irrespective of the percentage of gel or crosslinking density. The capacity of MEW to produce well‐defined out‐of‐plane fibers and the ability to increase the shear properties of fiber‐reinforced hydrogel composites are highlighted.     

轮胎工业用更安全的操作油

在欧洲，立法和公众压力正在使欧洲市场上的操作油性质发生变化。这引起欧洲橡胶行业对不使用有潜在致癌危险芳香油的新型轮胎和橡胶配方进行评述。本文对这一状况进行了研究，并探讨了美国市场上可能出现的动态，介绍了不同产品的需求量以及北美操作油和润滑油制造不断变化的局面。提供了轮胎配合用新一代操作的油制造方法及各种竞争油类性能的对比数据。     

Platelet-activating factor type activity in plasma from patients with septicemia and other diseases

The purpose of the present study was to determine whether increased levels of platelet-activating factor (PAF) type activity can be detected in plasma from patients with septicemia and other diseases. A level of PAF below 0.5 ng/mL of plasma was considered normal. We found that plasma from a patient with adverse anaphylactoidic reaction to intravenous analgetics contained 2.1 ng PAF/mL. In seven patients with septicemia, including urosepsis, endocarditis and peritonitis, and with positive blood culture, increased plasma PAF levels (1–20 ng PAF/mL) were observed. Other patients with clinical indications of septicemia had negative blood cultures and/or increased levels of C-reactive protein (CRP). Yet, in the plasma from these patients, no increased PAF levels were detected under the assay conditions used. Two patients with allergic asthma, requiring treatment with steroids, had no measurable plasma PAF. In the plasma from a patient with idiopathic thrombocytopenic purpura (ITP) only an “endogenous” inhibitor of PAF induced platelet aggregation was initially observed. In spite of this, the patient responded to treatment with the PAF antagonist WEB 2086 with a dramatic increase in platelet count (Lohmannet al., Lancet ii, 1147, 1988). Thereafter, also increased PAF levels (3.3 ng PAF/mL) were detected in plasma, although some “endogenous” inhibitor of PAF was still present. In conclusion, increased PAF levels in plasma from patients support a role of PAF in certain human disease states, such as in anaphylactoid reaction, sepsis and septic shock. The type, relevance and specificity of endogenous inhibitors of PAF deserve further study. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

节省时间的组合式密炼机

节省时间的组合式密炼机Ｄｉｐｌ－ＬｉｎｇＪｕｅｒｇｅｎＰｏｈｌｅｔａｌ．著刘倩怡译吴秀兰校９０年代密炼机的设计应适应目前经济、环保、安全及易于维护保养的需要。鉴于密炼机的平均寿命约为３０年，Ｗｅｒｎｅｒ＆Ｐｆｌｅｉ－ｄｅｒｅｒ公司已研制出一种组合式密...     

Kilovolt Blumlein pulse generator with variable pulse duration and polarity

A Blumlein pulse generator which utilizes the superposition of electrical pulses launched from two individually switched pulse forming lines has been designed and tested. By using a power metal-oxide-semiconductor field-effect transistor as a switch on each end of the Blumlein line, we were able to generate pulses with amplitudes of 1 kV across a 100 Omega load. Pulse duration and polarity can be controlled by the temporal delay in the triggering of the two switches. Using this technique, we have demonstrated the generation of pulses with durations between 8 and 60 ns. The lower limit in pulse duration was determined by the switch closing time and the upper limit by the length of the pulse forming line. A further advantage of the concept is that pulse distortions caused by the non-negligible on-resistance of a line with a single switch can be eliminated by using switches with identical characteristics.     

Process chain development for the rapid prototyping of microstructured polymer, ceramic and metal parts: composite flow behaviour optimisation, replication via reaction moulding and thermal postprocessing

Different variants of reaction moulding techniques exploiting the rapid light-induced photopolymerisation of reactive resins are widely used in microsystem technologies for the fabrication of plastic components or for rapid prototyping (RP) purposes. In this paper, the further development of micro reaction moulding with respect to a rapid prototyping of ceramic and metal parts will be described. As in powder injection moulding, the process sequence binder–filler–formulation, replication, debinding and sintering has to be passed. The mould filling and, hence, the accurate reproduction of surface details depend strongly on the composite’s viscosity, which is a function of the filler load. Especially, an improved process control of the composite formation prior to moulding and the thermal debinding is crucial for the realisation of microstructured ceramic or metal parts. The development of the whole process chain and some examples will be presented. This paper was originally presented at the International Conference on Multi-Material Micro Manufacture (4M), Karlsruhe, Germany, 29 June 2005 to 1st July 2005, and is extended for publication in this journal.     

Binomial Group-Testing With an Unknown Proportion of Defectives

The binomial group-testing problem is extended to the case in which the common probability p of a unit being defective is unknown. A Bayes “non-mixing” procedure R ⁽¹⁾ is derived and compared with other procedures, in particular with the corresponding procedure R ₁ that requires the knowledge of p and with another procedure based on continually revising the maximum likelihood estimate of p; the latter is called an empirical Bayes solution. Finally, a Bayes procedure derived in the Appendix allows “mixing” and this is conjectured to be the unrestricted Bayes solution; the improvements due to “mixing” are shown to be small in Table III. Several applications of the general problem of group-testing are discussed in the introduction and this virtually constitutes a general review of the subject. After the procedure R ⁽¹⁾ is defined a detailed illustration is given in section 2.1 showing how to carry out this procedure with the use of Tables I and II. Lower bounds for the Bayes risk associated with any group testing procedure for unknown p are given in Table III; one of these bounds, based on information theory, is derived in section 4.