Variable Time Impulse System Optimization with Continuous Control and Impulse Control

Optimal control of a variable time impulse system is considered in this study. Besides impulse control, the system is assumed to operate with continuous control also. Necessary conditions for the optimization of such system are derived using the calculus of variations. A reinforcement based solution technique called a single network adaptive critic (SNAC) method is developed in this paper to obtain an optimal solution. Details of the SNAC‐based algorithm are presented. Simulation examples are also presented for illustrative purposes.     

Chemical,antioxidant, functional and thermal properties of rice bran proteins after yeast and natural fermentations

The paper focuses on the chemical, antioxidant, functional and thermal properties of rice bran proteins after yeast, natural fermentations and unfermented rice bran. Protein content of yeast‐fermented rice bran protein concentrate (YFRBPC), naturally fermented rice bran protein concentrate (NFRBPC) and unfermented rice protein concentrate (UFRBPC) were 72.50%, 68.92% and 65.73%, respectively, while ash content were 4.72%, 4.61% and 3.04%, respectively. The total amino acids of YFRBPC, NFRBPC and UFRBPC were 123.16, 118.45 and 99.39, respectively. DPPH radical inhibition of YFRBPC, NFRBPC and UFRBPC were 58.62%, 55.29% and 47.14%, respectively, while ferric reducing ability power were 0.73, 0.58 and 0.41 mmol TE per gram, respectively. The highest foam capacity of UFRBPC (57.56%), NFRBPC (64.15%) and YFRBPC (76.00%) was observed at pH 9.0. YFRBPC and NFRBPC were lighter in colour than UFRBPC. YFRBPC had higher denaturation temperature and enthalpy value than NFRBPC and UFRBPC. The β‐sheets structures were more in YFRBPC and NFRBPC than UNFBPC.     

Integrated approach for assembly tolerance analysis

In mechanical design, tolerance assignment is a critical but complex task since the designer will not only have to consider the associated cost to achieve a certain tolerance level, but also the cost due to failure in assembling task. These associated tolerance costs as well as the failure rate are fuzzy in nature. This paper presents an integrated approach to incorporate manufacturing costs of certain tolerance specifications into design stages for automatic tolerance assignment and design. Tolerance design is interdisciplinary in nature and is characterized by a highly uncertain environment. In recent years, fuzzy logic has appeared as a credible alternative for tolerance design. A fuzzy based tolerance representation scheme is presented to model three dimensional (3D) tolerances. With this representation, relative assembly tolerance constraints can be expressed. A fuzzy tolerance generation and assignment process for assembly is discussed. Fuzzy tolerance equations are generated for 3D assembly considerations. Manufacturing process information, along with uncertain cost information modelled in fuzzy terms, is added to the system to arrive at a cost-optimal tolerance assignment.     

Agile product development through CAD and rapid prototyping technologies: an examination in a traditional pump-manufacturing company

The pump industry is the one which is yet to exhibit agile characteristics by evolving new models quickly in accordance with the dynamic demands of the customers. The researchers have not yet explored the potential of infusing agile characteristics in the pump industry. In order to initiate exploration in this direction, the research reported in this paper was carried out. To begin with, the empirical equations used for designing the pump components namely impeller and casing were referred. Subsequently, a software to compute the parameters using these empirical equations was developed. By inputting these parameters in a Pro/E software package, four new solid models of impeller and casing were designed. These newly designed models were subjected to analysis using GAMBIT and FLUENT software packages. Subsequently, rapid prototyping technology was adopted to develop the prototype of one of those models of impeller. In order to obtain the industry view of this research, four practicing experts were approached with a questionnaire to gather their reactions. The results of their reactions indicated that this research could be practically applied to achieve agile product development through the interfacing of computer-aided design (CAD) and rapid prototyping technologies.     

Anisotropy in impact behavior of Zr-2.5Nb pressure tube alloy

Zr-2.5Nb alloy tubes in cold worked and stress relieved (CWSR) condition serve as pressure boundary for hot coolant in Indian Pressurized Heavy Water Reactor (IPHWR). Due to both microstructural and crystallographic anisotropy, the mechanical properties in general and fracture behavior in particular are anisotropic for this material/component. In this work impact behavior of the pressure tube material was characterized over a range of temperature by impact test using specimens with crack growth direction along axial and transverse directions of the tubes. It has been found that both temperature and orientation have strong influence on the absorbed impact energy.     

Microindentation fracture behavior of surface modified alumina ceramic using glass infiltration

This study investigates the effect of a low expansion glass (Mg₃Al₂Si₆O₁₈) treatment on the surface fracture toughness of sintered alumina. The surface fracture toughness was determined by direct indentation method (Vickers indentations), carried out at different loads ranging from 9.8 to 196 N. The crack lengths on the surface at each load were found to be decreased (8–12%) by glass treatment and the corresponding crack resistance values increased by about 17–20%. Both sintered and glass treated specimens showed rising trend in crack resistance values as the indentation load was increased. There was also a significant increase in the Weibull modulus value of crack resistance. Improved properties of glass treated sample were attributed to the formation of a relatively larger process zone surrounding the crack, crack arrest behavior due to the compressive stresses and the crack bridging phenomena. The compressive stresses were generated from the thermo-elastic properties mismatch: (a) between the glass and the ceramic in the glass infiltrated zone, and (b) the glass–ceramic composite layer and the ceramic substrate.     

Spectral,thermal, and photoreactivity studies on epoxy resin containing benzylidene units in the main chain

A photosensitive epoxy resin was synthesized from bis(4‐hydroxy ‐3‐methoxy benzylidene) acetone and epichlorohydrin using solution polycondensation method. The prepared epoxy resin was characterized by UV, IR, ¹H NMR, and ¹³C NMR spectroscopy. The thermal stability of the epoxy resin was assessed by thermogravimetric analysis. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The photocrosslinking property and photopolymerizing ability of the epoxy resin were studied in film and solution state using UV spectroscopy. The effect of photo acid generator and sensitizer on photosensitivity of the resin was also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of cutting parameters on the degree of work hardening and tool life during high-speed machining of Inconel 718

The use of superalloy Inconel 718 is increasing in most of the sophisticated applications like aircraft engines, industrial gas turbines, rocket engines, space vehicles, submarines, etc. Hence, in-depth understanding of this material helps to determine the ability of this material to withstand severe conditions of stress, temperature, corrosion, and controls its longevity and reliability. In the present work, an attempt has been made to study the relationship of degree of work hardening and tool life as a function of cutting parameters like cutting speed, feed, depth of cut, untreated tungsten carbide and postcryogenic-treated tool. Work hardening and tool life are the major factors which need to be controlled/improved to enhance the machinability characteristics of superalloy Inconel 718. A significant performance in tool life was observed due to cryogenic treatment given to tungsten carbide tool. Moreover, it was observed that optimized cutting parameters not only minimized/controlled work hardening characteristics but also improved tool life while high-speed machining of Inconel 718.     

Effect of halophytic compost along with farmyard manure and phosphobacteria on growth characteristics of Arachis hypogaea Linn

Organic compost has been identified as an alternative to chemical fertilizer to increasing soil fertility and crop production in sustainable farming. The objective of the present study was to evaluate the effects of halophytic compost which are normally available in coastal areas on growth parameters in Arachis hypogaea. Halophytic compost along with farmyard manure (FYM) and phosphate solubilising bacteria (PSB) resulted in production of highest biomass such as plant height, number of compound leaves, total number of root nodules, fresh and dry weight of root nodules and fresh and dry weight of plant. Various combination of halophytic composts used in the present study, Suaeda compost+farmyard manure+phosphate solubilising bacteria treatment showed an enhanced biomass when compared to other halophytic compost and control.