Technical review: Improvement of mechanical properties and suitability towards armor applications – Alumina composites

Ceramic Matrix Composites (CMCs) have many interesting properties, mainly light weight, cost efficiency, low density, high compressive strength, high hardness and durability. Hence, they emerged as a boon to the development of personnel armors in the past. The current work aims to review various new methodologies adapted for the reinforcement of Alumina (Al₂O₃) CMCs in recent times, including some of the interesting results obtained with respect to mechanical properties, suitability of the synthesized composites for armor applications, and the upcoming reinforcement trends. Finally, studies related to reinforcement in Al₂O₃ CMCs, specifically towards armor applications have been consolidated to arrive at some of the important inferences for concluding reasonably.     

Electrocatalytic Reduction of CO2 to Ethylene by Molecular Cu‐Complex Immobilized on Graphitized Mesoporous Carbon

The electrochemical reduction of carbon dioxide (CO₂) to hydrocarbons is a challenging task because of the issues in controlling the efficiency and selectivity of the products. Among the various transition metals, copper has attracted attention as it yields more reduced and C2 products even while using mononuclear copper center as catalysts. In addition, it is found that reversible formation of copper nanoparticle acts as the real catalytically active site for the conversion of CO₂ to reduced products. Here, it is demonstrated that the dinuclear molecular copper complex immobilized over graphitized mesoporous carbon can act as catalysts for the conversion of CO₂ to hydrocarbons (methane and ethylene) up to 60%. Interestingly, high selectivity toward C2 product (40% faradaic efficiency) is achieved by a molecular complex based hybrid material from CO₂ in 0.1 m KCl. In addition, the role of local pH, porous structure, and carbon support in limiting the mass transport to achieve the highly reduced products is demonstrated. Although the spectroscopic analysis of the catalysts exhibits molecular nature of the complex after 2 h bulk electrolysis, morphological study reveals that the newly generated copper cluster is the real active site during the catalytic reactions.     

Impact of adhesive ingredients on adhesion between rubber and brass-plated steel wire in tire

Proficiency on underlying mechanism of rubber-metal adhesion has been increased significantly in the last few decades. Researchers have investigated the effect of various ingredients, such as hexamethoxymethyl melamine, resorcinol, cobalt stearate, and silica, on rubber-metal interface. The role of each ingredient on rubber-metal interfacial adhesion is still a subject of scrutiny. In this article, a typical belt skim compound of truck radial tire is selected and the effect of each adhesive ingredient on adhesion strength is explored. Out of these ingredients, the effect of cobalt stearate is found noteworthy. It has improved adhesion strength by 12% (without aging) and by 11% (humid-aged), respectively, over control compound. For detailed understanding of the effect of cobalt stearate on adhesion, scanning electron microscopy and energy dispersive spectroscopy are utilized to ascertain the rubber coverage and distribution of elements. X-ray photoelectron spectroscopy results helped us to understand the impact of Cu_XS layer depth on rubber-metal adhesion. The depth profile of the Cu_XS layer was found to be one of the dominant factors of rubber-metal adhesion retention. Thus, this study has made an attempt to find the impact of different adhesive ingredients on the formation of Cu_XS layer depth at rubber-metal interface and establish a correlation with adhesion strength simultaneously.     

Lean philosophy: implementation in a forging company

This research addresses the implementation of lean philosophy in a forging company with a focus on radial forging production flow lines. Here, the prime motive is to evolve and test several strategies to eliminate waste on the shop floor. In this research, a systematic approach is suggested for the implementation of lean principles. This paper describes an application of value stream mapping (VSM). Consequently, the present and future states of value stream maps are constructed to improve the production process by identifying waste and its sources. Furthermore, Taguchi’s method of design of experiments is pursued here to minimize the forging defects produced due to imperfect operating conditions. A noticeable reduction in set-up time and work-in-process (WIP) inventory level is substantiated. Finally, we conclude with a discussion of managerial implications and the future scope of research.     

The Design of Discrimination Experiments

Experimentation plays a fundamental role in scientific discovery. Scientists experiment to gather data, investigate phenomena, measure quantities, and test theories. In this article, we address the problem of designing experiments to discriminate between two completing theories. Given an initial situation for which the two theories make the same prediction, the experiment design problem is to determine how to modify the situation such that the two theories make different predictions for the modified situation. The modified situation is called a discrimination experiment. We present a knowledge-intensive method called DEED for designing discrimination experiments. The method analyzes the differences in the two theories' explanations of the prediction for the initial situation. Based on this analysis, it determines modifications to the initial situation that will result in a discrimination experiment. We illustrate the method with the design of experiments to discriminate between several pairs of qualitative theories in the fluids domain.     

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.     

Does histology influence outcome in childhood Hodgkin's disease? Results from the United Kingdom Children's Cancer Study Group

PURPOSE: Histology has been identified as an important prognostic factor in Hodgkin's disease (HD) in adults. Information regarding the impact of histology on outcome in childhood HD is scarce. This study determines the effect of histology on the overall survival (OS) or progression-free survival (PFS) in a national series of children treated in a standardized manner. PATIENTS AND METHODS: The results of treatment of 331 assessable patients, treated between January 1, 1982 and June 30, 1992, in the United Kingdom Children's Cancer Study Group (UKCCSG) Hodgkin's study I were reviewed to evaluate OS, PFS, and deaths according to stage and histology. Treatment was either involved-field radiation alone (stage IA) or chlorambucil, vinblastine, procarbazine, and prednisolone (ChlVPP) chemotherapy with or without mediastinal radiation. All were clinically staged at diagnosis. RESULTS: Nodular sclerosing (NS) HD was the most common histologic subtype (155 of 331 patients [47%]) and was uniformly distributed through all stages. Lymphocyte-depletion (LD) HD was extremely uncommon (< 1%). Mixed-cellularity (MC) HD had the highest relapse rate, but this was only significant (P < .05) in stage I patients who received local irradiation alone. There was no other statistically significant difference in OS and PFS between the various histologic subtypes. Multivariate analysis for PFS and OS confirmed that stage was the most important prognostic factor and that histology did not have an effect after stratification by stage. CONCLUSION: This study demonstrates that with effective multiagent chemotherapy, histologic subtype does not influence outcome. The high relapse rates in stage I MC subtype indicates that MC HD is biologically aggressive and systemic treatment with or without local irradiation may be indicated. The high relapse rate in stage IV patients appeared to be independent of histology.     

One-step oxidation of cyclohexane to adipic acid

Liquid-phase oxidation of cyclohexane with Co(III) catalyst and gaseous oxygen was found to be influenced by reaction temperature, catalyst concentration and the duration. Maximum adipic acid product selectivity (77%) with about 85% cyclohexane conversion was attained at 100°C using catalyst: cyclohexane molar ratio 0·08. Under these conditions more than 80% cyclohexane was converted in the first hour, although selectivity to adipic acid continued to increase for the next 5 h. Cyclohexyl acetate and cyclohexyl monoadipate were identified as important intermediates. This study supports the mechanism proposed by Schultz, J. G. D. and Opchenko, A., J. Org. Chem., 38 (21) (1973) 3729.