Manufacturing cell formation with production data using neural networks

Batch type production strategies need adoption of cellular manufacturing (CM) in order to improve operational effectiveness by reducing manufacturing lead time and costs related to inventory and material handling. CM necessitates that parts are to be grouped into part families based on their similarities in manufacturing and design attributes. Then, machines are allocated into machine cells to produce the identified part families so that productivity and flexibility of the system can be improved. Zero-one part-machine incidence matrix (PMIM) generated from route sheet information is commonly presented as input for clustering of parts and machines. An entry of ‘1’ in PMIM indicates that the part is visiting the machine and zero otherwise. The output is generated in the form of block diagonal structure where each block represents a machine cell having more than one machines and a part family. The major limitations of this approach lies in the fact that important production factors like operation time, sequence of operations, and lot size of the parts are not accounted for. In this paper, an attempt has been made to propose a clustering methodology based on adaptive resonance theory (ART) for addressing these issues. Initially, a methodology considering only the operation sequence of the parts has been proposed. Then, the methodology is suitably modified to deal with combination of operation sequence and operation time of the parts to address generalized cell formation (CF) problem. A new performance measure is proposed to quantify the performance of the proposed methodology. The performance of the proposed algorithm is tested with benchmark problems from open literature and the results are compared with the existing methods. The results clearly indicate that the proposed methodology outperforms the existing methods in most cases.     

Organophosphorus and DGEBA resins containing clay nanocomposites: flame retardant,thermal, and mechanical properties

Flame-retardant nanocomposites were prepared from diglycidylphenylphosphate (DGPP) and modified montmorillonite (MMT) clay blended with DGEBA in different ratio. T _g of all formulations increased with increasing clay content in the respective series while decreasing with increasing DGPP content. The TGA, LOI, and UL-94 data of all nanocomposites indicated that the materials were thermally stable with high flame retardancy resulting from synergetic effect of phosphorus and inorganic clay. The XRD analysis of the nanocomposites with 1 and 2% of clay indicated the intercalation of clay while rest of the samples displayed exfoliation at high clay content. As compared to neat epoxy system, a maximum increase of 59.3, 45.5, and 93% of tensile, flexural, and impact strengths were observed for the prepared nanocomposites. The SEM analysis of the failure surfaces of all DGPP containing samples showed rough with ridge patterns and river markings on the fracture surface that serves in improving the mechanical properties.     

Fat Mimicking Properties of Citric Acid Treated Sweet Potato Starch

Fat mimicking properties of citric acid treated sweet potato starch were investigated in this present study. Citric acid treated sweet potato starch was prepared by treating the native sweet potato starch with 3% citric acid for 6 h at a temperature of 45°C. Dextrose equivalent value of citric acid treated sweet potato starch was 2.05%. A significant increase in amylose content was noticed in citric acid treated sweet potato starch possibly due to the lyses of amylopectin fractions. The melting temperature of citric acid treated sweet potato starch was 51.44°C, which was close to the melting point of fat. Citric acid treated sweet potato starch exhibited superior water holding capacity and in vitro digestibility. Gel strength and enthalpy (?H) of citric acid treated sweet potato starch were comparatively lower than native sweet potato starch; correspondingly, citric acid treated sweet potato starch confirmed a low pasting profile. Native sweet potato starch and citric acid treated sweet potato starch exhibited a shear-thinning behavior. Acid treatment did not alter the granule size of native sweet potato starch (≈8 µm). Hence, this study concluded that citric acid treated sweet potato starch would be used as a potential fat replacer in food preparations due to its fat mimicking properties.     

Liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates

Three series of liquid crystalline and photocrosslinkable poly(4,4′‐stilbeneoxy) alkylarylphosphates were synthesized from various 4,4′‐bis(m‐hydroxyalkyloxy)stilbenes (m = 2, 4, 6, 8, 10) and arylphosphorodichloridates in chloroform by solution polycondensation method. Polarized optical microscope (POM) and differential scanning calorimetry (DSC) observations revealed that polymers containing less than four methylene spacer groups did not exhibit liquid crystalline (LC) texture, possibly due to smaller microdomain and restricted movement of the mesogen. In contrast, polymers containing more than four methylene spacer group established LC texture, which has been attributed to the larger monodomain and free movement of mesogens. Thermogravimetric analysis (TGA) data indicated that thermal stability and char yield decreased with increasing flexible methylene spacer groups, increased significantly for biphenyloxy and 1‐naphthyloxy containing polymers than that of phenyloxy containing polymers ascribed to increasing aromaticity, size, and number of aromatic rings. Photocrosslinking of stilbene containing polymers has been shown to proceed via 2π‐2π cycloaddition reaction by Ultra‐violet (UV) and fluorescence. The rate photocrosslinking has been found to increase with increasing number of methylene group in the main chain. The aromaticity of the side chain also increases the rate of crosslinking. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Conservation and deferral potentials of demand side management programmes: A case study

Demand side management options (DSMO) can reduce the peak electricity demand for utilities. This reduction in demand is helpful to the utility in at least two ways: first, it minimizes the penalty costs of not being able to meet the peak demand and thus it has the potential to reduce costs; second, it also can defer the need for building new power plants and hence it can release, at least for some period of time, the scarce capital (which is especially important for the developing countries) for use in development activities elsewhere. These two benefits have been considered in detail in the paper. An analytical model has been developed to estimate the conservation potential of the DSM programmes. The model is then used to illustrate the benefit derived by deferring the construction of a new power plant. The model has been applied to the Maharashtra State Electricity Board, an electric utility in India, as a case study. Several scenarios have been constructed to account for different levels of the DSM possibilites. A sensitivity analysis has been carried out to tackle some of the uncertainties associated with the assumptions in the analysis.     

Preparation of graphene–TiO2 nanocomposite and photocatalytic degradation of Rhodamine-B under solar light irradiation

GR–TiO₂ nanocomposite was prepared by simple chemical method using graphene oxide and titanium isopropoxide (Ti [OCH (CH₃)₂]₄) precursors. The crystalline nature of the composite was characterised by powder X-ray diffraction and the intercalation was explained by Raman spectroscopy. The morphology of the composite was analysed by field emission scanning electron microscopy. The elemental and quantitative measurement of the composite was determined by electron dispersive spectroscopy. The shape and size of the particle was measured by transmission electron spectroscopy and high resolution spectroscopy. The surface area and elemental composition of the composite was studied by using Brunauer–Emmett–Teller (BET) method and X-ray photoelectron spectroscopy. Photo-generated electrons were studied by photoluminescence spectra. The photocatalytic activity of nanocomposite was investigated by the degradation of Rhodamine-B (Rh-B) in an aqueous solution under solar light irradiation. The GR–TiO₂ demonstrates photocatalytic activity in the degradation with a removal rate of 98% under solar light irradiation as compared with pure TiO₂ (42%), graphite oxide (19%), and mechanical mixture GR + TiO₂ (60%) due to the increased light absorption intensity and reduction of electron–hole pair recombination with the intercalation of graphene and TiO₂. The results indicated that the GR–TiO₂ could be used as a catalyst to degrade Rh-B from coloured wastewater.     

Azimuthal Variation of Measured HF Noise

HF noise (2-8 MHz) as a function of azimuth, frequency, and time of day was measured in England during the winter of 1966-1967. For a given frequency interval eight unequal azimuthal sectors (with five sectors between 45°-180°) were sampled each four hours in a standardized fashion. Power levels for the tenth, fiftieth, and ninetieth percentiles were derived and plotted. The results provide the integrated total external noise (both local and propagated). In addition to the well-known distinctive diurnal and frequency changes, a marked variation with azimuth is present. A separate examination of noise intensities measured simultaneously from several azimuths reveals strong differences with azimuth. The investigation indicates that noise levels as a function of azimuth are needed and are the ones to be applied to practical HF systems.     

Understanding industrial energy use: Physical energy intensity changes in Indian manufacturing sector

This study develops and examines physical energy intensity indicators in five industrial sub-sectors—iron and steel, aluminum, textiles, paper, and cement—and investigates mitigation options for energy related CO₂ emissions (during 1991–2005). Decomposition analysis has been employed to separate the structural effect (share of different products in the sector) from pure intensity effect (efficiency increase through technical improvement) for each industry. The results show that the combined effect (considering both structural and intensity effects together) on both iron and steel and paper and pulp industries is negative while it is positive for aluminum and textiles. The intensity effect for all the industries, barring textiles, is negative showing improvement in energy efficiency; iron and steel in particular, has seen a decrease of 134 PJ in energy consumption owing to improvements in efficiency. However, energy intensity in textiles has risen by 47 PJ due to increased mechanization. Structural effect is positive in aluminum and iron and steel industries indicating a movement towards higher energy-intensive products. In the case of aluminum, positive structural effect dominates over negative intensive effect whereas negative intensive effect dominates iron and steel industry. The paper helps in designing policies for improving productivity and reduce energy consumption in India's manufacturing sector.