Current status,enablersand barriers of implementing cellular manufacturing system in Indian industries

The cellular manufacturing (CM) has been proved as a well-known manufacturing strategy that helps to improve manufacturing efficiency and productivity by
utilizing the philosophy of group technology. Large number of papers has been published in the area of design issues of CM system. Unfortunately, the issues related to acceptability of CM in Indian industries are typically not examined rigorously as technical issues. This paper presents the results of a survey carried out to find the status, enabler and barrier of implementing CM system in Indian industries.     

Mechanical Anisotropy and Pressure Induced Structural Changes in Piroxicam Crystals Probed by In Situ Indentation and Raman Spectroscopy

The ability to correlate mechanical and chemical characterization techniques in real time is both lacking and powerful tool for gaining insights into material behavior. This is demonstrated through use of a novel nanoindentation device equipped with Raman spectroscopy to explore the deformation-induced structural changes in piroxicam crystals. Mechanical anisotropy was observed in two major faces (\( 0\bar{1}1 \)) and (011), which are correlated to changes in the interlayer interaction from in situ Raman spectra recorded during indentation. The results of this study demonstrate the considerable potential of an in situ Raman nanoindentation instrument for studying a variety of topics, including stress-induced phase transformation mechanisms, mechanochemistry, and solid state reactivity under mechanical forces that occur in molecular and pharmaceutical solids.     

Milk Derived Antimicrobial Bioactive Peptides: A Review

In recent decades, bioactive peptides have attracted increasing interest as health promoting functional foods. A variety of naturally formed bioactive peptides have been found in fermented dairy products such as yogurt, sour milk, and cheese. Initially these peptides are inactive within the sequence of the parent protein molecule and can be generated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures, and/or hydrolysis by proteolytic enzymes. Milk derived peptides exert a number of health beneficial activities, even upon oral administration. Bioactive peptides have a great impact on major body systems including the digestive, nervous, endocrine, cardiovascular, diabetes type II, obesity, and immune systems. Antimicrobial peptides are also an important ingredient of innate immunity, especially at mucosal surfaces such as lungs and small intestine that are constantly exposed to a range of potential pathogens. Therefore, it plays an important role in boosting natural immune protection by reducing the risk of chronic diseases. Bioactive peptides are considered as potent drugs with well-defined pharmacological residues and also used to formulate health-enhancing nutraceuticals.     

Ultrabroad supercontinuum generation in tellurite equiangular spiral photonic crystal fiber

Simulations are presented of a very broad and flat supercontinuum (SC) in both the normal and anomalous group velocity dispersion regimes of the same equiangular spiral photonic crystal fiber at low pumping powers. For a pump wavelength at 1557?nm and average pump power of 11.2?mW, we obtained a bandwidth >3?μm (970?nm–4100?nm) at 40 dB below the peak spectral power with fiber dispersion ～2.1?ps/km nm at 1557?nm. In the same fiber, at pump wavelength 1930?nm and average pump power of 12?mW the SC bandwidth was more than two octaves (1300?nm–3700?nm) and dispersion was ～1.3?ps/km nm at 1930?nm. This demonstrates the potential use of the fiber for multi-wavelength pumping with commercially available sources at fairly low power.     

Incorporating production concerns in conceptual product design

This paper presents a set of analytical tools that can be used to alter a product's design, manufacturing processes and assembly techniques to increase production rate. The analytical tools obtain these improvements by simultaneously considering each part's geometric attributes and complexity, vendor selection, material and process selection, and capacity planning at the conceptual stage of the product realization process. The method detects and then avoids heavily used resources by indicating which combination of one or more of its components' geometric attributes, manufacturing processes, material and assembly methods should be altered. The method is illustrated with the analysis of an overhead projector. It is shown that production rate can be doubled by either making small changes to a component's geometric attributes or by selecting different manufacturing processes. Neither of these changes affects the functionality of the product.     

Elucidating the thermal, chemical, and mechanical mechanisms of ultraviolet ablation in poly(methyl methacrylate) via molecular dynamics simulations

[Figure: see text]. Laser ablation harnesses photon energy to remove material from a surface. Although applications such as laser-assisted in situ keratomileusis (LASIK) surgery, lithography, and nanoscale device fabrication take advantage of this process, a better understanding the underlying mechanism of ablation in polymeric materials remains much sought after. Molecular simulation is a particularly attractive technique to study the basic aspects of ablation because it allows control over specific process parameters and enables observation of microscopic mechanistic details. This Account describes a hybrid molecular dynamics-Monte Carlo technique to simulate laser ablation in poly(methyl methacrylate) (PMMA). It also discusses the impact of thermal and chemical excitation on the ensuing ejection processes. We used molecular dynamics simulation to study the molecular interactions in a coarse-grained PMMA substrate following photon absorption. To ascertain the role of chemistry in initiating ablation, we embedded a Monte Carlo protocol within the simulation framework. These calculations permit chemical reactions to occur probabilistically during the molecular dynamics calculation using predetermined reaction pathways and Arrhenius rates. With this hybrid scheme, we can examine thermal and chemical pathways of decomposition separately. In the simulations, we observed distinct mechanisms of ablation for each type of photoexcitation pathway. Ablation via thermal processes is governed by a critical number of bond breaks following the deposition of energy. For the case in which an absorbed photon directly causes a bond scission, ablation occurs following the rapid chemical decomposition of material. A detailed analysis of the processes shows that a critical energy for ablation can describe this complex series of events. The simulations show a decrease in the critical energy with a greater amount of photochemistry. Additionally, the simulations demonstrate the effects of the energy deposition rate on the ejection mechanism. When the energy is deposited rapidly, not allowing for mechanical relaxation of the sample, the formation of a pressure wave and subsequent tensile wave dominates the ejection process. This study provides insight into the influence of thermal, chemical, and mechanical processes in PMMA and facilitates greater understanding of the complex nature of polymer ablation. These simulations complement experiments that have used chemical design to harness the photochemical properties of materials to enhance laser ablation. We successfully fit the results of the simulations to established analytical models of both photothermal and photochemical ablation and demonstrate their relevance. Although the simulations are for PMMA, the mechanistic concepts are applicable to a large range of systems and provide a conceptual foundation for interpretation of experimental data.     

CFD simulation of flow pattern and plume dimensions in submerged condensation and reactive gas jets into a liquid bath

Submerged gas jets into a liquid bath are widely used in metal processing and thermal processes. These systems are classified as (a) condensation jet and (b) reaction jet systems. This paper presents the CFD simulation of both the types of jets. The CFD model considers phase change, gas-liquid and gas-gas reactions and the accompanied rates of mass transfer. Mass transfer coefficient was estimated using small eddy model where the value of mass transfer coefficient is calculated based on the local values of turbulent kinetic energy (k) and the dissipation rate (ε). A good agreement with the available experimental data of plume length validates the CFD model. The CFD simulations have also been compared with the available experimental data on velocity and temperature profiles which shows excellent agreement. A comparison between the condensation and the reaction jets has been presented in terms of plume dimensions, flow and temperature patterns. The relative predictions of the present model and the rational correlations have been presented for the estimation of plume length for both the types of jet systems.     

Role of surface composition in morphological evolution of GaAs nano-dots with low-energy ion irradiation

The surface chemistry of GaAs (100) with 50-keV Ar⁺ ion beam irradiation at off-normal incidence has been investigated in order to elucidate the surface nano-structuring mechanism(s). Core level and valence band studies of the surface composition were carried out as a function of fluences, which varied from 1 × 10¹⁷ to 7 × 10¹⁷ ions/cm². Core-level spectra of samples analyzed by X-ray photoelectron spectroscopy confirmed the Ga enrichment of the surface resulting in bigger sized nano-dots. Formation of such nano-dots is attributed to be due to the interplay between preferential sputtering and surface diffusion processes. Valence band measurement shows that the shift in the Fermi edge is higher for Ga- rich, bigger sized nano-dots due to the partial oxide formation of Ga. ‘One-dimensional power spectral density’ extracted from atomic force micrographs also confirms the significant role of surface diffusion in observed nano-structuring.     

Determination of cholesterol in dairy products by infrared techniques: 2. FT-NIR method

A Fourier transformed near-infrared (FT-NIR) method for rapid determination of cholesterol in dairy products was demonstrated. FT-NIR spectrum of pure cholesterol was characterized and the region between 3550 and 3650 cm⁻¹ was found to be the most significant in cholesterol content determination. The FT-NIR method was found to accurately predict the cholesterol content in a variety of dairy products with r ² value greater than 0.98 and SEP estimates of less than 1.70. The FT-NIR procedure with suitable multivariate statistical model was further validated by recovery studies and compared with a conventional method. Results indicate that FT-NIR has the potential for rapid estimation of cholesterol.