The Impingement Heat Transfer Data of Inclined Jet in Cooling Applications: A Review

On the impingement heat transfer data,the experimental studies of air and liquid jets impingement to the flat surfaces were collected and critically reviewed.The oblique impingements of both single circular and planar slot jets were considered in particular.The review focused on the surface where the jet impingement cooling technique was utilized.The nozzle exit Reynolds numbers based on the hydraulic diameter varied in the range of 1,500–52,000.The oblique angles relative to the plane surface and the dimensionless jet-to-plate spacing vary in the range of 15°–90°and 2–12 respectively.The review suggested that the magnitude of maximum heat transfer shifted more for air jets compared with the liquid jets.The drop in the inclination angle and the jet-to-plate separation led to the increase in the asymmetry of heat transfer distribution.The displacement of maximum Nusselt number(heat transfer)locations was found to be sensitive to the inclination angle and the smaller jet-to-plate distance.Also,the Nusselt number correlations proposed by various researchers were discussed and compared with the results of the cited references.     

Hydrolysis of Milk Fat By Lipase in Solvent-free Phospholipid Reverse Micellar Media

Butterfat was hydrolyzed with lipases contained in lecithin reverse micelles. The influence of pH, temperature, molar ratio of surfactant to water (R) and surfactant concentration on the hydrolytic reaction indicated linear, quadratic, and interactive effects for reaction systems mediated by R. javanicus and C. rugosa lipases. The initial reaction rate was dependent on reaction parameters; however, the degree of hydrolysis was independent of pH. Both enzymes exhibited high thermal stability. The content and composition of milk fat hydrolysates prepared by R. javanicus lipase were most influenced by reaction temperature and R. The optimum conditions for production of free fatty acids, monoacyl-glycerols, diacylglycerols and specific regio-isomers were defined.     

Uneven (and Divergent) Technological Accumulation among Advanced Countries: Evidence and a Framework of Explanation

We present evidence for the advanced OECD countries of unevenand divergent patterns of technological accumulation. We showthat ‘global’ firms will not smooth out the differences,since their technological activities are strongly influencedby conditionsin their own countries. We suggest that—in addition to diversity in cumulative technological trajectories7— the divergent patterns reflect international differencesin the capacities of management, financial and training institutionsproperly to evaluate— and exploit— the learningbenefits of technological investments. For these reasons, weconclude that technological gaps among the advanced OECD countriesare here to stay.     

Spectral response of rice crop and its relation to yield and yield attributes

Ground-based radiometric measurements were conducted on six varieties of rice crop during an entire growth cycle using a hand-held seven-band radiometer. Concomitant measurements of some of the yield attributes were also made. Spectral data were also collected on a single variety grown under 12 different fertilizer treatments. Spectral data have been correlated with leaf area index, total wet biomass, total dry biomass, plant water content and final grain, straw and total yield. The results show similar temporal spectral responses of all six varieties and a strong correlation of agronomic parameters with spectral parameters derived from the near-infrared and red radiances. Red and near-infrared radiance ratio and normalized differences were found sensitive to the N fertilizer application but not to the P and K fertilizers. Linear correlations were observed between spectral parameters and final grain, straw and total yield     

Experimental and quantum chemical studies on corrosion inhibition performance of quinoline derivatives for MS in 1N HCl

The corrosion inhibition effect of two quinoline derivatives, viz, 2-chloro quinoline 3-carbaldehyde (CQC) and (2-chloro-quinoline-3ylmethyl)-p-tolyl-amine (CQA) have been investigated against mild steel (MS) in 1N HCl solution using conventional weight loss, potentiodynamic polarization, linear polarization and electrochemical impedance spectroscopy. The losses in weights of MS samples have proved that both CQC and CQA are efficient inhibitors of corrosion. The mixed mode of inhibition was confirmed by electrochemical polarizations. The results of electrochemical impedance spectroscopy have showed changes in the impedance parameters like charge transfer resistance and double-layer capacitance that confirmed strong adsorption of inhibitors on the MS surface. The inhibition action of these compounds was assumed to occur via adsorption on the steel surface through the active centres contained in the molecules. Furthermore, quantum chemical calculations have been performed at B3LYP/6-31G(d, p) level to complement the experimental evidence.     

Computation of invariant zeros of linear,time-invariant,multivariable systems

In this paper a numerical method is presented for computing the invariant zeros of a controllable linear, time-invariant, multivariable system described by the 4-tuplo (A, B, C, D) or the triple (A, B, C). The method is based on the fact. that a controllable system can be made maximally unobservable by means of state variable feedback, thereby causing the cancellation of the invariant zeros by an equal number of the system poles. The invariant zeros are obtained as the eigenvalues of a matrix of the same dimension as the number of invariant zeros. The method is applicable to both multivariable as well as single-input, single-output systems. Examples are given to illustrate the use of the method.     

The System Zirconia-Scandia

The system zirconia-scandia was investigated using X-ray diffraction analysis, differential thermal analysis, metallographic analysis, and melting point studies. Results reveal the monoclinic α₁ phase (0 to 2 mol% Sc₂O₃), the tetragonal α₂'phase (5 to 8% Sc₂O₃), the rhombohedral β phase (9 to 13% Sc₂O₃), the rhombohedral γ phase (15 to 23% Sc₂O₃), the rhombohedral δ phase (24 to 40% Sc₂O₃), and the cubic % phase (77.5 to 100% Sc₂O₃). The monoclinic α₁ phase and the tetragonal α₂'phase were found to transform to the tetragonal α₂ phase over a wide temperature range depending on composition. The β, γ, and α phases transformed to a cubic phase at temperatures of %600^%, 1100^%, and 1300^%C, respectively. A maximum melting point of %2870^%C was found at %10% Sc₂O₃ and a eutectic at %2400^%C at 55% Sc₂O₃.     

Heat exchanger performance: the use of food colourings for estimation of minimum residence time*

Most indicator systems used in estimation of residence time are not compatible with food usage The food colours carbon black and copper chlorophyll were found to give satisfactory absorption properties without causing interaction problems when used in milks, cream and ice cream mixes for determination of residence times in a pilot-scale plate heat exchanger.     

The Sorption of Mixtures of Direct Dyes by Cellulose

The diffuse adsorption model accounts adequately for the adsorption of mixtures of direct dyes by cellulose if no interaction occurs between the dyes in either phase and if allowance is made for ionised carboxyl groups in the cellulose.