Using a neural network for predicting the average grain size in friction stir welding processes

In the paper the microstructural phenomena in terms of average grain size occurring in friction stir welding (FSW) processes are focused. A neural network was linked to a finite element model (FEM) of the process to predict the average grain size values. The utilized net was trained starting from experimental data and numerical results of butt joints and then tested on further butt, lap and T-joints. The obtained results show the capability of the AI technique in conjunction with the FE tool to predict the final microstructure in the FSW joints.     

Fatigue of cold worked ribbed reinforcing bar—a fracture mechanics approach

A theoretical method for the prediction of fatigue life of structural members containing external stress raisers has been developed. The method is based on a linear elastic fracture mechanics approach to fatigue. The theory has been applied to fatigue of Torbar steel in concrete beams. The required parameters for such application were obtained from fatigue tests on samples and finite element analysis of cracked bars. Comparisons between the theory and experimental data taken from other investigations have shown that the theory predicts a reasonable lower limit fatigue life of Torbar in concrete beams. The theory has also successfully predicted the effect of the minimum stress on the fatigue life of this type of bar.     

A model-based survey of alert correlation techniques

As telecommunication networks evolve rapidly in terms of scalability, complexity, and heterogeneity, the efficiency of fault localization procedures and the accuracy in the detection of anomalous behaviors are becoming important factors that largely influence the decision making process in large management companies. For this reason, telecommunication companies are doing a big effort investing in new technologies and projects aimed at finding efficient management solutions. One of the challenging issues for network and system management operators is that of dealing with the huge amount of alerts generated by the managed systems and networks. In order to discover anomalous behaviors and speed up fault localization processes, alert correlation is one of the most popular resources. Although many different alert correlation techniques have been investigated, it is still an active research field. In this paper, a survey of the state of the art in alert correlation techniques is presented. Unlike other authors, we consider that the correlation process is a common problem for different fields in the industry. Thus, we focus on showing the broad influence of this problem. Additionally, we suggest an alert correlation architecture capable of modeling current and prospective proposals. Finally, we also review some of the most important commercial products currently available.     

In Vitro Simultaneous Transfer of Lipids to HDL in Coronary Artery Disease and in Statin Treatment

The exchange of lipids with cells and other lipoproteins is a crucial process in HDL metabolism and for HDL antiatherogenic function. Here, we tested a practical method to quantify the simultaneous transfer to HDL of phospholipids, free-cholesterol, esterified cholesterol and triacylglycerols and to verify the lipid transfer in patients with coronary artery disease (CAD) or undergoing statin treatment. Twenty-eight control subjects without CAD, 27 with CAD and 25 CAD patients under simvastatin treatment were studied. Plasma samples were incubated with a donor nanoemulsion prepared by ultrasonication of the constituent lipids and labeled with radioactive lipids; % lipids transferred to HDL were quantified in the HDL-containing supernatant after chemical precipitation of non-HDL fractions and the nanoemulsion. The assay was precise and reproducible. Increase of temperature (4–37 °C), of incubation period (5 min to 2 h), of HDL-cholesterol concentration (33–244 mg/dL) and of mass of nanoemulsion lipids (0.075–0.3 mg/μL) resulted in increased lipid transfer from the nanoemulsion to HDL. In contrast, increasing pH (6.5–8.5) and albumin concentration (3.5–7.0 g/dL) did not affect lipid transfer. There was no difference between CAD and control non-CAD with regard to the lipid transfer, but statin treatment reduced the transfer to HDL of all four lipids. The test herein described is a valid and practical tool for exploring an important aspect of HDL metabolism.     

Natural organic matter and sunlight accelerate the degradation of 17ß-estradiol in water

Nanomolar concentrations of steroid hormones such as 17β-estradiol can influence the reproductive development and sex ratios of invertebrate and vertebrate populations. Thus their release into surface and ground waters from wastewater facilities and agricultural applications of animal waste is of environmental concern. Many of these compounds are chromophoric and susceptible to photolytic degradation. High intensity UV-C radiation has been demonstrated to degrade some of these compounds in engineered systems. However, the degradation efficacy of natural solar radiation in shallow fresh waters is less understood. Here photolytic experiments with 17β-estradiol demonstrated modest photodegradation (~ 26%) when exposed to simulated sunlight between 290 and 720 nm. Photodegradation significantly increased (~ 40-50%) in the presence of 2.0-15.0 mg/l of dissolved organic carbon (DOC) derived from humic acids of the Suwannee River, GA. However, rates of photodegradation reached a threshold at approximately 5.0 mg/l DOC. Observed suppression of photolysis in the presence of a radical inhibitor (i.e. 2-propanol) indicated that a significant proportion of the degradation was due to radicals formed from the photolysis of DOC. Although photodegradation was greatest in full sunlight containing UV-B (290-320 nm), degradation was also detected with UV-A (320-400 nm) and visible light (400-720 nm) alone.     

Research into integrated design and manufacturing based on STEP

This paper discusses a typical STEP-compliant manufacturing environment, which effectively integrates two systems. The first generates native data that retain the information needed to machine a part on a particular machine tool, whereas the second carries out optimization for machining parameters using the dispatched information from the first system. The related research work is divided into four areas, feature generation, macro process planning, micro process planning, and machining execution. The main part of the paper is devoted to reviewing the most recent research publications. The publications have been organized into the four areas as mentioned above. The discussion section that follows looks at the STEP-compliant research from the perspectives of industrial adoption, feature recognition for process planning, challenges in STEP-enabled inspection and STEP-NC controllers.     

Excitation Transfer in Porous Silicas — A Fractal Approach

In this paper, we present both experimental data and a theoretical study of the excited state energy transfer in irregular systems. Picosecond time-resolved luminescence techniques were employed to resolve the fluorescence curves of both donor and acceptor molecules. By analyzing the kinetics of direct electronic energy transfer, the effective dimensions describing the distributions of adsorbed dye molecules on the surfaces of silica gels and controlled-pore glasses were obtained. The same dimensions for silica gels were obtained in fluorescence depolarization experiments in one-component (only donors) systems and in migration-accelerated trapping (indirect energy transfer) measurements.     

The role of catalyst synthesis on the enhancement of nickel praseodymium (III) oxide for the conversion of greenhouse gases to syngas

Clean Technologies and Environmental Policy - Catalytic methane (CH4) dry reforming (MDR) reaction proceeds with the formation of carbon; hence the effects of the catalyst preparation method on the...