A new efficient algorithm for computing the imprecise reliability of monotone systems

Reliability analysis of complex systems by partial information about reliability of components and by different conditions of independence of components may be carried out by means of the imprecise probability theory which provides a unified framework (natural extension, lower and upper previsions) for computing the system reliability. However, the application of imprecise probabilities to reliability analysis meets with a complexity of optimization problems which have to be solved for obtaining the system reliability measures. Therefore, an efficient simplified algorithm to solve and decompose the optimization problems is proposed in the paper. This algorithm allows us to practically implement reliability analysis of monotone systems under partial and heterogeneous information about reliability of components and under conditions of the component independence or the lack of information about independence. A numerical example illustrates the algorithm.     

Physicochemical comparison of electroslag remelting with consumable electrode and electroslag refining with liquid metal

The paper is devoted to comparison of electroslag remelting (ESR) with consumable electrode and electroslag refining with liquid metal (ESR LM) processes. The possibility of rearrangement of the heat contributions coming from the consumable electrode and current supplying mould (non-consumable electrode, CSM) makes the core of the ESR process organisation in the CSM. The usage of liquid metal instead of consumable electrodes allows to reduce liquid bath temperature and volume in order to provide low segregation ingot. The formal assessment of physico-chemical conditions and experimental measurements of desulphurisation have shown the same level of refining ability of both processes. Replacing the classic ESR by the ESR LM is a prospective way to produce high-quality ingots from sophisticated and hard-to-deform materials, whereas manufacturing of the consumable electrodes is technically problematic and costly.     

Bayesian hierarchical model with MCMC for optical cable flame retardancy tests

We report a model and method for calculating the probability of an optical fiber cable passing a flame retardancy test (FRT). The method uses a Bayesian approach that accounts for variations in the experimental conditions between tests. We show that adding a hierarchy to the empirical model shrinks the posterior distributions and discuss the applicability of the hierarchical model to various test environments. The model uses the average smoke parameter as the predictor and can be extended to other test responses such as the peak smoke, flame spread, or toxicity.     

Microprocessor Adaptive Control of Oil Temperature for Robot Arm Valves: A Practical Implementation

An assembly line quality control robotic arm has to have a very accurate regulation of the hydraulic oil temperature. An adaptive control strategy is designed and implemented, based on on-line parameter identification and optimum integral compensation realization. Design details, implementation, and performance data are presented.     

Kinetics of homogeneous catalytic chlorination of acetic acid

The kinetics of the chlorination of acetic acid (HAc) to monochloroacetic acid (MCA) and the physical solubility of chlorine in HAc and its mixtures with MCA were investigated in a laboratory scale semibatch reactor. The temperature dependence of the Henry's constant was determined from solubility data obtained at temperatures between 70°C and 110°C. The kinetic experiments were performed at 75–100°C with 3–13 mol % acetyl chloride (AcCl) and 0–5 weight % H₂SO₄ added as catalysts. Gas chromatography was used to determine the concentrations of HAc, MCA, dichloroacetic acid and AcCl during the experiments. The results indicate that the reaction rate is independent of the concentrations of HAc and Cl₂ whereas the reaction is significantly enhanced by MCA and H₂SO₄. The effects are explained by a reaction mechanism involving the acid catalyzed enolization of AcCl as the rate-determining step. A rate equation based on this mechanism was derived. Kinetic constants included in the equation were determined by regression analysis.     

On the Road to Personalized Medicine: Multiscale Computational Modeling of Bone Tissue

Personalized medicine is an emerging field, considered by many in the biomedical community to be among the upcoming approaches to medical treatment. To embrace this new challenge, physicians need a better understanding of the biological processes in the human body, as well as precise diagnostic tools and patient-specific treatments. In response, the last three decades have witnessed a major shift in tissue engineering development, from treating bone tissue at the macro-scale level only to treating it at complex multiscale levels. Researchers have begun striving for a better understanding of bone structure and mechanics, and then applying this knowledge in designing new medical treatments and procedures. Today computational methods, including finite element analyses, are the tool of choice for biomechanical research of bone tissues. Moreover, bone multiscale modeling can become a vital part of a comprehensive computerized diagnostic system for patient-specific treatment of metabolic bone diseases, fractures and bone cancer. This review paper describes the state of the art in multiscale computational methods used in analyzing bone tissue. The discussed methods and techniques can serve as a base for the creation of such an envisioned diagnostic system.