Estimation of storage space requirements using multiple regression

Two equations hove been obtained using regression analysis techniques which can be applied to determine storage space requirements with acceptable accuracy and minimum effort. By defining all items by means of a common parameter—packing factor—it was possible to ignore the individual weights of each item, yet still load the transport and storage unit to some practical load limits. The method used in this paper is general and can be applied to similar problems with different boundary conditions.     

Remote sensing technique for mapping salt affected soils

The salt affected soils of Etah, Aligarh, Mainpuri and Mathura districts have been mapped into S1: < 10 per cent of the area covered by salts, S2: 10–30 per cent, S3: 30–50 per cent, S4: 50–75 per cent and S5: > 75 per cent using an integrated approach of image interpretation. The dull white tone of salt affected and sandy soils have posed problems in their discrimination, on TM false colour composite, however, the problem of spectral similarity was solved through integration of interpretation of thermal data (10.4–12.5μm) with TM FCC (bands 2, 3, 4) interpretation. The discrimination of salt affected soils was significantly better on data between March and first week of April because of maximum contrast. Out of l-75m ha of the total geographical area, the salt affected soils account for 11–8 per cent. Another 16–2 per cent is likely to be affected with this problem if similar degraded conditions prevail there. The values of pH: 8–7 and ECe: 1–3 dsm^-1 of S1 soils group them into non saline and mildly alkali class. Similarly low ECe: 4–4dSm^-1 and high pH: 9–8 for S3 soils and high ECe: 24–0 dsm^-1 and very high pH: 10–7 of S4/S5 soils, placed the soils into alkali and sodic classes respectively. The gypsum requirement based on pH values varies from 1 to 15 tha^-1.     

HYDRODYNAMICS OF MAGNETOFLUIDIZED ADMIXTURE BEDS

Hydrodynamic behavior of a magnetofluidized bed is investigated over a wide range of magnetic-field intensity values as a function of superficial air velocity. The bed comprises of different proportions of copper and iron particles and is contained in a Plexiglas column of 0.102?m internal diameter. The uniform constant magnetic field is created by a Helmholtz electromagnet. In particular, the bed pressure drop is measured as a function of superficial air velocity and characteristic bed voidage and fluidizing velocities are determined at minimum fluidization and bubbling bed conditions. These characteristic properties of the magnetically stabilized fiuidized beds are reported as a function of magnetic-field intensity, and are correlated by suitable expressions. These will be useful for prediction purposes related to design and operation.     

Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium-doped zinc oxide nanorods

Undoped and aluminium (Al)-doped zinc oxide (ZnO) nanorods have been synthesized by electrochemical route. The synthesized materials have been characterized by X-ray diffraction, UV–visible spectrometer and scanning electron microscope. The Al-doped ZnO nanorods have been coated with polyvinyl alcohol. Current–voltage characteristics have been investigated in dark and under UV-light illumination. Aluminium doping in ZnO increase its electrical conductivity and further polyvinyl alcohol coating on Al-doped ZnO increase UV sensitivity of the material. Response and recovery time of Al-doped ZnO and PVA-coated Al-doped ZnO nanorods have been recorded. PVA-coated Al-doped ZnO nanorods shows very fast response and recovery time of 10 s in comparison to uncoated ZnO (20 min) nanorods.     

Bubble Column Reactors and Fischer-Tropsch Synthesis

Three-phase slurry bubble column reactors have been used extensively in a number of chemical, petrochemical, and biochemical process engineering applications. For the success of these operations and their large scale industrial exploitation, it is essential that their transport and chemical characteristics be adequately understood on a mechanistic basis so that appropriate design criteria and optimum operating conditions can be established. It is the purpose of this review to present such available knowledge in relation to chemical catalytic operations. The mass transfer characteristics, catalytic activity, and mixing patterns of different phases necessitate a detailed understanding of the hydrodynamic behavior and catalyst dispersion in slurry bubble column reactors. The current status of these aspects is presented, discussed, and assessed in this review. Chemical and biochemical reactions are exothermic in nature and hence efficient heat removal devices must be installed in the reactor to preserve its isothermal behavior and chemical catalytic activity by avoiding temperature runaway. Extensive work recently conducted from this heat transfer viewpoint is reviewed and appraised. The bubble dynamics, and slurry mixing and movement characteristics of such baffled bubble columns are significantly different from those of unbaffled bubble columns. Very limited information is available on baffled bubble column operations and this is reviewed and critically examined. An important application of the slurry bubble column is in the synthesis of fuel gases on suspended catalyst particle surface to produce chemicals. One such example is the Fischer-Tropsch synthesis of hydrogen and carbon monoxide in what is referred to as indirect coal liquefaction technology. Pilot plant efforts of this nature and their successes are briefly mentioned. Mathematical details and models developed from time to time to characterize catalytic bubble column operations are briefly described and discussed. In the context of available information and its integration presented here, the specific needs for future experimental and theoretical research work are pointed out.     

OPTIMUM DESIGN OF SMALL DISTRIBUTION TRANSFORMER USING ALUMINIUM CONDUCTORS

ABSTRACT

Design Optimization of distribution transformer of small KVA rating using aluminium conductors is considered as a nonlinear multivariable constrained programming problem. For this purpose a set of five independent design variables is identified and suitable constraints are imposed to meet the thermal and other performance requirements of the transformer. The various objective functions are formed in terms of cost of active material, capitalized cost of losses as the operating cost and the overall cost as the sum of these two. This is done to select most effective and appropriate optimized design for these types of transformers. The optimization is achieved through Rosenbrock's method of direct search in conjunction with the sequential unconstrained minimization Technique (SUMT). The optimized design results for a 25 KVA distribution transformer using aluminium conductors are presented along with the design results using copper as the winding material for different objective functions.     

Role of iron oxide impurities in electrocatalysis by multiwall carbon nanotubes: An investigation using a novel magnetically modified ITO electrodes

The role of iron oxide impurities in the electrocatalytic properties of multiwall carbon nanotubes (MWCNTs) prepared by catalytic chemical vapour decomposition method (CCVD) is studied in detail. A novel magnetically modified electrodes have been developed by which MWCNTs were immobilized on indium-tin oxide (ITO) electrodes, without any chemical binders. The electro-catalytic oxidation of dopamine, and reduction of hydrogen peroxide have been studied by cyclic voltammetry on magnetically modified electrodes with (i) MWCNTs with occluded iron oxide impurities (Fe-MWCNTs), (ii) MWCNTs grown on iron oxide nanoparticle particulate films (Io-MWCNTs) and (iii) pristine iron oxide nanoparticle particulate film (Io-NPs). A shift towards less positive potentials for the oxidation of dopamine was observed which is in the order of Fe-MWCNTs < Io-MWCNTs < Io-NPs. Similarly, trend towards less negative potentials for the reduction of hydrogen peroxide was observed. Thus, the electrocatalytic activities displayed by MWCNTs have been attributed to the iron oxide impurities associated with it. The systematic variation was related to the nature of interaction of iron oxide nanoparticles with MWCNT surface.     

RHEOLOGICAL PROPERTIES OF CHEMICALLY MODIFIED RICE STARCH MODEL SOLUTIONS

Native rice starches have poor resistance to shear, and fair stability to retrogradation with soft texture, which can be altered through chemical modifications. Starch from broken pieces of rice of three rice cultivars (PUSA‐44, PR‐106 and PR‐114) was chemically modified by etherification and esterification reactions by different combinations of modification reagents to investigate the effect of modification on the rheological properties of rice starches. The modification resulted in shear stable gel with apparent pseudoplastic characteristics. The viscosity of starches increased upon acetylation and dual modification as a result of increase in solubility. However, cross‐linking had shown the reverse effect. The flow behavior index (n) and consistency coefficient (k) were significantly (P ≤ 0.05) improved upon modification in acetylated and dual‐modified starches. The effect of modification on the rheological properties was observed in similar pattern in all the three rice cultivars but varied significantly in variety PUSA‐44 may be because of its relatively higher amylose content.