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An individual’s accountability to oneself leads to self-regulatory behaviour. A field experiment afforded an opportunity to test this relation, given that external accountability conditions were absent. A single group pre-test/post-test design was used to test the hypothesis. A group of full-time resident management students, n ≈ 550, take four meals during the day in the institute mess. As a part of the experiment, food wastage in the form of leftovers on the plates of subjects was measured. As a pre-test, the measurement occurred at two levels. Subjects could see how much they are adding to the total waste by looking at a weighing scale placed under a waste basket, and they could also see the total waste data for each of the four meals for the day and a day earlier displayed at a prominent place. After 105 days, the weighing scale under the basket was removed, and as a post-test measurement, the total waste data for the four meals were noted down for another 72 days. A manipulation test indicated that the experiment has had the desired effect of invoking self-accountability in subjects during the pre-test phase, and diluting it during the post-test phase. Time series analysis of pre-test and post-test data indicated that the wastage data decreased in the pre-test phase. However, the post-test waste data showed an increase over a period of time. The results indicate that accountability conditions like social norms invoke self-accountability cognition leading to self-regulatory behaviours in individuals.

Numerical computations have been realized to explore and evaluate the laminar mixed convection heat transfer from a heated trapezoidal bluff body. Two different configurations of the trapezoidal bluff body viz. expanded and tapered considered and a comparison has been made at different operational parameters. The spectrum of physical control parameters considered as Reynolds number (Re) = 10–50, Richardson number (Ri) = 0–1, and Prandtl number (Pr) = 0.7 (air). A finite volume method implemented on the collocated grid arrangement has been employed for numerical computations. Overall drag and lift coefficients are found higher for a tapered body as compared to an expanded body. However, average Nusselt number is greater for the expanded body as compared to the tapered one. With increase in Re at a given Ri, total drag coefficient is found to decrease in steady regime, but it increases in time-periodic regime. On increasing Ri, drag and lift coefficients decrease in the steady regime for both geometries. A correlation expressing the functional relationship of average Nusselt number with Re and Ri for both geometries has been proposed. Critical Re at Ri = 0.5 for the expanded geometry is found to be between Re = 46 and 47, while for the tapered body it exists between Re = 35 and 36. Maximum heat transfer enhancement for the tapered body with respect to the expanded body at Ri = 0, 0.5, and 1 is found to be approximately 26, 24, and 21%, respectively.

Extensive numerical computations for the confined flow and heat transfer of shear-thinning fluids over two long tandem triangular bluff bodies are performed for Reynolds number (Re) = 1–40, power-law index (n) = 0.2–1, and gap ratio (S/B) = 1–4 for a fixed blockage ratio and Prandtl number of 25% and 50, respectively. The values of critical Re are obtained for each of the two triangular cylinders for all S/B and n. Augmentation in heat transfer for the two tandem triangular cylinders is calculated with respect to both S/B and n.

The effects of non-Newtonian power-law fluids on the unsteady unconfined fluid flow characteristics of an equilateral triangular prism are investigated for Reynolds number (Re) ranging from 50 to 150 and power-law index (n) ranging from 0.4 to 1.8. The flow field around a triangular prism is represented by streamline contours. The output parameters such as root-mean-square values of lift and drag coefficients, time-averaged drag and lift coefficients and Strouhal number are calculated. A time-periodic behavior of the flow is observed for the entire range of control parameters studied. An increment in the time-averaged total drag coefficient is observed with the increase in Re for pseudo-plastic and Newtonian fluids. However, for dilatant fluids, a mixed trend is observed when time-averaged total drag coefficient is varied with n. There is an enhancement in the value of Strouhal number with the increase in Re for dilatant fluids, whereas a mixed trend of Strouhal number with Re is noticed for pseudo-plastic fluids.

The present study is concerned with the simulation of incompressible Newtonian fluid flow and heat transfer over a long semicircular bluff body in a channel at low Reynolds numbers. In particular, wall effects on the forced convection from a (heated) semicircular cylinder confined in a horizontal channel are investigated for Reynolds number = 1–40 and blockage ratio = 16.67–50% for air as the working fluid. Flow and thermal fields are found steady for the preceding range of settings. The onset of flow separation increases as the wall confinement increases. The size of the recirculation zone downstream of a semicircular cylinder is seen to increase almost linearly with Reynolds number for a fixed blockage ratio, but it decreases with increasing blockage ratio for a fixed Reynolds number. As expected, total drag coefficient and its components decrease with increasing value of Reynolds number. However, with increasing blockage ratio, the values of these drag coefficients increase. On the basis of equal proje...

A numerical analysis using Ansys Fluent was carried out to investigate the forced convection of power-law fluids (power-law index varying from 0.2 to 1.8) around a heated semi-circular cylinder with wall confinement (or blockage ratio) of 25%, Prandtl number of 50, and Reynolds numbers 1–40. Flow and thermal fields were found to be steady for Re up to 40. The shear-thickening behavior was found to have a higher value of drag coefficient, whereas the shear-thinning behavior had a smaller value of drag coefficient when compared with Newtonian fluids in the steady regime. The wake size was found shorter in shear-thickening fluids than Newtonian and shear-thinning fluids. An overall heat transfer rate was calculated and found to increase with the rise in Reynolds number. The average Nusselt numbers were observed higher for shear-thinning fluids than Newtonian and shear-thickening fluids; and the maximum enhancement in the heat transfer was achieved approximately 47% as compared to Newtonian fluids. The present results have also been correlated in terms of wake length, drag coefficient and average Nusselt number expressions for various Reynolds numbers and power-law indices studied. In addition, the effects of blockage ratios ranging from 16.67% to 50% on the engineering output parameters with varying power-law index at Re = 40 were reported.

The present study focuses on the flow across an asymmetrically confined (heated) cylinder in a channel for fluids obeying Ostwald-de Wale (power-law) equation for the settings: Reynolds number (Re) = 1–40, power-law index (n) = 1–1.8, gap ratio (γ) = 0.375–1, blockage ratio (β) = 0.2–0.5 and Prandtl number (Pr) = 1–50. Total drag coefficient and its individual components have been analyzed as a function of Re, β, γ and n. The overall drag coefficient was found to increase with blockage and behavior of fluid, while it drops gradually for increasing Re. The asymmetrical configuration is seen to mitigate the overall as well as individual drag coefficients. The surface heat transfer coefficient in the form of average Nusselt number and the Colburn heat transfer jh factor has been thoroughly discussed. Heat transfer rate is found to increase with increasing Reynolds number and wall confinement, while increasing dilatant behavior impedes the same. As expected, heat transfer results have been reconciled in a single curve by way of the Colburn jh factor. The jh factor is found higher for the symmetric case as compared to the asymmetric case.

Flow characteristics of non-Newtonian power-law fluids in a right-angled horizontal T-channel are studied in the laminar regime. In particular, the two-dimensional numerical computations are performed using Ansys Fluent for the following range of physical parameters: Reynolds number (Re) = 5–200 and power-law index (n) = 0.2–1 (covering shear-thinning, n

The failure of the pressure vessel containing pressure liquefied petroleum gas leads to Boiling Liquid Expanding Vapour Explosion (BLEVE). Further, ignition of released gas results in the formation of fireballs. In the present paper the semi-empirical equations are presented that represent the impact assessment of thermal radiation hazards from the liquefied petroleum gas fireball. Also an attempt has been made to determine the safe separation distance.

The present work aims at studying the laminar flow and heat transfer characteristics of a Newtonian fluid over a row of semi-circular cylinders placed in uniform cross-flow configuration. The effects of spacing to diameter (gap) ratio, varied from 1 to 10, on the flow and heat transfer patterns have been studied at a Reynolds number of 100 for air as the working fluid. There has been no significant interaction in the flow at a spacing ratio greater than 4 and each semi-circular cylinder behaved more or less like the situation of a single cylinder. At lower gap ratios, the flow becomes more complicated due to the shear layer interactions that exist in the flow. The streamline and isotherm contours have been presented and discussed in detail for various gap ratios. The variation in flow behavior is explored further by studying the drag coefficient and lift coefficient signals of various semi-circular cylinders. The presence of a secondary frequency at low gap ratios that has adverse effect on the drag coefficient has been confirmed. The variation of measured global quantities, namely the drag coefficient, the Strouhal number and the Nusselt number have been studied and discussed in detail.

In this study, the feasibility of glycerol valorization into homo- and hetero-polymers of polyhydroxyalkanoates by a sludge isolated Bacillus sp. RER002 in a 3 L bioreactor was investigated. A mathematical model including logistic, Luedeking–Piret, and Luedeking–Piret-like equations that simulated the active residual biomass growth, P(3HB) synthesis, and glycerol consumption, respectively, was developed. In order to describe the dynamics of batch P(3HB) production, the model kinetic parameters viz., µmax, K1, K2, α, β, and KN were optimized using the stochastic search-based genetic algorithm. The synthesis of P(3HB) wasobserved to be highly growth associated and partially non-growth associated as reflected in a significant higher values of K1 (0.2435–0.5477) than K2 (2.2 × 10−6 to 9.1 × 10−3) within the glycerol concentration range of 10–40 g/L. Besides, the maximum 3.2g/L of copolymer [P(3HAscl-co-3HAmcl)] was observed at 30 g/L of glycerol concentration in synthetic crude glycerol medium with a yield coefficient (YP/S) of 0.16 g/g. Furthermore, the analyses of chemical and thermal properties of copolymer P(3HAscl-co-3HAmcl) revealed its enhanced material properties which make it suitable for various applications.

Effects of cross-buoyancy mixed convection on flow and heat transfer characteristics of a long semi-circular cylinder (long in neutral direction) in a confined channel have been investigated in the laminar regime. The numerical results have been presented and discussed for the range of conditions as Reynolds number (Re) = 1–40, Richardson number (Ri) = 0–4, Prandtl number (Pr) = 0.71–50 and blockage ratio (β) = 16.67%–50%. The drag coefficient increases with increasing Richardson number and/or blockage ratio. The average Nusselt number is showing a maximum relative enhancement of approximately 45% for Ri = 4 with respect to corresponding forced convection value (Ri = 0). The average Nusselt number increases with increase in Prandtl number and shows a maximum relative enhancement of approximately 1136% for Pr = 50 with respect to corresponding value at Pr = 0.71. On the other hand, the maximum relative variation of the total drag coefficient is found to be approximately 55% for Ri = 4 with respect to corresponding value at Ri = 0. Finally, the simple heat transfer correlation is obtained for the proceeding range of control parameters.

Two-dimensional numerical simulations are carried out to understand the effects of cross-buoyancy on the confined flow and heat transfer characteristics over an equilateral triangular bluff body at low and intermediate Reynolds numbers (Re). For a fixed Richardson number (Ri), an average cylinder Nusselt number increases with increasing Re. However, the average Nusselt number shows a soft response toward increasing Ri. The critical Re for the onset of periodic unsteady flow increases with increasing cross-buoyancy (Ri). A simple heat transfer correlation is also obtained to relate the values of average cylinder Nusselt number, Re, and Ri.

The effects of wall confinements (β) and of Prandtl numbers (Pr) on the laminar flow around a heated trapezoidal prism are investigated numerically for Pr = 0.71–100 and β = 12.5–50 % at low Reynolds numbers (Re). The critical value of the Reynolds number (i.e., the transition from a steady to a time-periodic regime) is calculated and it exists between Re = (36 and 37), (60 and 61) and (91 and 92) for the blockage ratios of 12.5, 25 and 50 %, respectively. The average Nusselt number increases with increasing Re and/or Pr and/or blockage ratio. The variation of local Nusselt number on each surface of the obstacle and the representative isotherm contours are presented to elucidate the role of Pr and blockage ratio on the heat transfer from the trapezoidal prism. The maximum heat transfer enhancement with respect to a square prism on the basis of equal projected area is found to be approximately 31 and 45 % for the blockage ratios of 12.5 and 25 %, respectively, for Pr = 0.71 and Re = 1. The Colburn heat transfer factor correlations are also obtained for the preceding range of settings. Finally, the influence of Richardson number (Ri = 0–1) on the flow and heat transfer characteristics has been studied for air as working fluid.

This study involves the numerical solution of the laminar heat transfer in a separating and reattaching flow by simulating the flow and heat transfer downstream of a backward-facing step. The in-house finite volume code has been implemented employing a hybrid differencing scheme and the SIMPLE algorithm for the pressure–velocity coupling. Three principal parameters governing heat transfer in this geometry, that is channel expansion ratio (ER), Reynolds number (Re), and Prandtl number (Pr), are systematically varied in the range ER = 1.111 to 2, Re = 1 to 200, and Pr = 0.71 to 100, and the simple correlations between these parameters have been elucidated. A series of important findings have been established by analyzing the results some of which are: (1) there is an associated shifting of the point of maximum heat transfer with respect to the flow-reattachment point with gradually decreasing the values of ER and (2) the heat transfer enhancement increases with the increase in Pr number as a result of the compression of the thermal boundary layer and the maximum Nusselt number varies as .

Confined flow and heat transfer phenomena across two long triangular bars in tandem arrangement in a horizontal channel have been studied for the range of Reynolds number (Re) = 1–40, Prandtl number (Pr) = 0.71–50 and gap ratio (S/B) = 1–4 for a fixed blockage ratio of 25%. The average Nusselt number of the first triangular cylinder is found to be larger than the corresponding value for the second triangular cylinder in the tandem configuration. Heat transfer correlations in terms of the Colburn jh factor have been established in the steady regime.

Power-law shear-thinning fluid flow over a heated square bluff body is numerically investigated under aiding buoyancy mixed convection at low Reynolds numbers. Semi-explicit finite volume code is developed to solve the governing equations along with the appropriate boundary conditions. Both aiding buoyancy and shear-thinning natures are found to augment the heat transfer rate from the surface of the long square bar. In aiding buoyancy, the total drag coefficient is found to be more for the square cylinder than that of the circular cylinder, whereas the average cylinder Nusselt number for the square cylinder is found to be lower than the circular one on equal side/diameter basis. Maximum augmentation in heat transfer is found to be approximately 20% with respect to forced convection. Finally, a heat transfer correlation is established by using the Colburn heat transfer factor.

Effects of wall confinements on the laminar flow and heat transfer around a heated tapered trapezoidal bluff body are investigated numerically in the confined domain (Reynolds number, Re = 1 to 40; blockage ratio = 0.125 to 0.5; and Prandtl number, Pr = 0.71). The onset of flow separation is found between Re = 4 and 5 for the blockage ratio of 0.125 and between Re = 5 and 6 for the blockage ratios of 0.25 and 0.5. If compared with a long circular obstacle on the basis of equal projected area, the total drag coefficient of the trapezoidal cylinder is found to be larger than the circular one, but an opposite trend is observed for the heat transfer. The augmentation in heat transfer for trapezoidal and circular cylinders is found to be approximately 46, 72, 74, and 65 percent for Re = 1, 5, 10, and 40, respectively for the blockage ratio of 0.25. The maximum enhancement in heat transfer for a tapered trapezoidal bluff body with respect to a square bluff body is found to be approximately 104 percent and 101 percent for blockage ratios of 0.25 and 0.5, respectively. Finally, simple correlations of wake length, drag, and average cylinder Nusselt number are established.

Mixed-convection flow and heat transfer of non-Newtonian power-law fluids over a pair of side-by-side circular cylinders in aiding buoyancy are investigated numerically. The calculations are perfor...

The present study focuses on momentum and heat transfer characteristics of the laminar flow of power-law fluids in a vertical channel with a built-in square cylinder under the influence of aiding buoyancy. The simulations are carried out at low Reynolds numbers (1–40) for the range of settings as power-law index = 0.4–1, Richardson number = 0–1, blockage ratio = 25%–50%, and Prandtl number = 50. It is found that the drag coefficient and the Nusselt number increase with the aiding buoyancy, while the shear-thinning behavior reduces the drag coefficient and increases the heat transfer rate.

A numerical investigation is conducted to analyze the steady and unsteady laminar flow and heat transfer in a channel with two square bars (of equal diameters) arranged side-by-side. The analysis is carried out for Reynolds number = 10–100, Prandtl number = 0.7–50, for transverse separation distance between the bars (i.e., gap ratio) of 1.5, 2, 2.5, 5, and 10 at the blockage ratio of 1/18. The results found here are in good agreement with previously published data. The effects of gap ratio, Reynolds number, and Prandtl number on the detailed kinematics of the flow and the heat transfer are presented. The engineering parameters such as total drag coefficient, average Nusselt number, and Strouhal number are calculated for the preceding range of conditions. It is observed that the overall drag coefficient decreases with increasing Reynolds number, whereas the average Nusselt number for the square cylinders increases with increasing Reynolds number and/or Prandtl number for all the values of gap ratios studie...

Flow and heat transfer of non-Newtonian power-law fluids over an inclined square cylinder placed inside a channel are studied numerically at low Reynolds numbers. In particular, calculations are carried out for Reynolds number (Re) = 1–40; power-law index (n) = 0.4–1 and blockage ratio (β) = 12.5–50% at a Prandtl number (Pr) = 50. An increase in blockage ratio results in an increase in the total drag coefficient and decrease in the wake length. The Strouhal number and the root mean square value of the lift coefficient increase with the increasing Reynolds number for the fixed values of blockage ratio and power-law index. The average Nusselt number increases with power-law index and/or blockage ratio. The maximum enhancement in heat transfer is approximately 49, 41, and 35% for the values of blockages of 50, 25, and 12.5%, respectively, as compared to the corresponding Newtonian value. The average Nusselt number for the inclined square cylinder (at α = 45°) is always greater than the average Nusselt number for the regular square cylinder (at α = 0). Finally, simple expressions of drag and Nusselt number have been established for the above range of settings. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res 43(2): 167-196, 2014; Published online 20 June 2013 in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21071

The new service management school of thought acknowledges a set of new human resource management (HRM) practices, underpinned by the concept of satisfaction mirror between customers and front-line workers. HRM practices in the cycle of success include careful selection, high-quality training, well-designed support systems, empowerment, teamwork, appropriate measurement, rewards and recognition, and the development of a service culture. The model for achieving cycle of success in interactive service works is known as the high involvement work systems (HIWS). There is some research evidence about the positive influence of high involvement HR practices on effective service delivery. This exploratory study examines the role played by HR practices in maintaining the quality of service delivery, in the context of healthcare services. It specifically studies the administrative factors and HR policies that aid effective service quality and the practices that bring down the quality of care provided in a private sector Indian hospital. This being a relatively new area, an inductive approach was used. The study relied on semi-structured interviews for the purpose of data collection. Along with data collection, core theoretical concepts were identified and tentative linkages were developed between the theoretical core concepts and the data. The findings show that the emphasis is more on supreme hospitality and patient amenities than medical treatment. The healthcare industry is witnessing a significant change. A consultant is no longer the ‘king’; this position has now been taken by the patients. Of late the emphasis is on patient satisfaction in terms of the facilities provided rather than the nature of medical treatment given. This is primarily so for organizations such as this hospital which aim at providing world-class care and for which ‘patient centricity’ is the hallmark. HR specific issues such as standardization of nursing activities, appraisal systems, effective communication channels, and compensation structure, all affect the quality of service provided in a hospital. Similar research can be conducted across other healthcare organizations to replicate and validate the findings regarding the changing scenario in the industry.

Steady and unsteady forced convection flow and heat transfer past a long expanded trapezoidal bluff body are investigated for the air as working fluid for Re = 1–150. The wake length increases as the Reynolds number increases in the steady flow regime (1 ⩽ Re ⩽ 47). The transition from steady regime to unsteady regime occurs between Re = 47 and 48. The total drag coefficient decreases with the increasing value of the Reynolds number up to Re = 90 and thereafter it increases with Reynolds number. However, heat transfer as well as Strouhal number increase with the increasing value of the Reynolds number. The maximum augmentation in heat transfer for the expanded trapezoidal cylinder with respect to the tapered trapezoidal cylinder is found to be approximately 146%. On the other hand, pressure drop shows an enhancement of approximately 97% for the expanded trapezoidal cylinder when compared with the tapered one. Simple correlations of wake length, drag, average Nusselt number and Strouhal number with Reynolds number have also been established.

Appraisee's perception of appraisal politics (APAP) is conceptualized to be formed by three perceptual dimensions. First is appraiser's manipulation of ratings to achieve their self-serving ends such as own reputation, maintaining good relationships, building in-groups, and handling dependency threats from appraisees. Second dimension constitutes fellow appraisees' upward influence behaviors to get higher ratings and rewards. Third dimension relates to the outcome of appraisal, i.e. pay and promotion decisions that can be discriminatory when performance is ignored. Such actions are detrimental for good performers and performance culture. Drawing from the organizational justice theories, it is proposed that APAP can be mitigated by those appraisal-related structural (e.g. criteria), process (e.g. voice) and contextual antecedents (e.g. relation with appraiser) that enhance appraisee's perceived control, understanding, and prediction of appraisal decision and process. These hypotheses were tested in the Ind...

This study focuses on the confined upward flow and heat transfer around a square cylinder under the effect of aiding buoyancy (Richardson number, Ri=0–1) in the vertical channel for Reynolds number (Re)=1–40 and blockage ratio (BR)=25–50% for the air as working fluid. Flow is found to be steady and symmetric for the range of settings. For Re≤2, no separation zone occurs for BR=25% and 30%. However, for BR=50%, no wakes are observed for Re≤3. The onset of flow separation takes place between Re=2 and 3 for BR=25% and 30%; whereas, for BR=50%, it exists between Re=3 and 4, irrespective of the value of Ri. Heat transfer correlations have also been obtained at different values of Re, BR and Ri.

Wall effects on the flow of incompressible non-Newtonian power-law fluids across an equilateral triangular cylinder confined in a horizontal plane channel have been investigated for the range of conditions: Reynolds number, Re=1–40, power-law index, n=0.4–1.8 (covering shear-thinning, Newtonian and shear-thickening behaviors) and blockage ratio=0.125–0.5. Extensive numerical results on flow pattern, wake/recirculation length, individual and overall drag coefficients, variation of pressure coefficient on the surface of the triangular cylinder and so forth are reported to elucidate the combined effect of power-law index, blockage ratio and Reynolds number. The size of vortices decreases with an increase in the value of the blockage ratio and/or power-law index. For a fixed value of the Reynolds number, individual and overall drags decrease with decrease in power-law index and/or blockage ratio in steady confined flow regime. Simple correlations of wake length and drag are also obtained for the range of settings considered.

Female Genital Tract (FGT) involvement with hematologic neoplasms is uncommon and the hematologic malignancies which involve the female genital organs are usually non-Hodgkin’s lymphoma. Involvement of the uterus and cervix with Acute Lymphoblastic Leukaemia (ALL) is extremely rare, and ovarian involvement is even rarer. We report the case of a young lady who presented with tubo-ovarian mass, excessive post-operative bleeding (post-total abdominal hystrerctomy and bilateral salpingo-oophorectomy) and was diagnosed to have ALL with blood and tissue involvement by histopathology and flow cytometry.

The two-dimensional numerical simulations of Newtonian fluid stream about a square bluff body have been studied in an unconfined configuration in addition in the propinquity of a plane wall. The comparison of flow and heat transfer constraints is done with the pure unconfined flow about a square obstacle. The set of physical constraints considered as Reynolds numbers (Re) = 100, 120 and Prandtl number (Pr) = 0.7 (air) at varying values of gap ratios (g). The values of drag and lift coefficients, and average Nusselt number are computed. The present study shows that on increasing the gap ratio, the drag coefficient is acquired to be the highest for the gap ratio of unity and it is observed the lowest for the unconfined case. Lift coefficient decreases and average Nusselt number increases with increasing gap ratio, but opposite effects are observed for the unconfined case. The flow becomes steady at low gap ratio, but on increasing gap ratio the flow behavior changes to periodic unsteady. The augmentation in heat transfer is found about 35 % for g = 1, with respect to the corresponding value for the unconfined case.

Flow and heat transfer of non-Newtonian power-law fluids across a pair of identical circular cylinders in side-by-side arrangement are investigated numerically by solving the continuity, momentum and energy equations along with the appropriate boundary conditions. The numerical calculations are performed in an unconfined computational domain for the following range of physical parameters: Reynolds number, Re = 1–40 and power-law index, n = 0.4–1.8 (covering shear-thinning, n n = 1 and shear-thickening, n > 1 behaviors) for gap ratio, T / D = 1.5–4.0 at a constant Prandtl number of 50. The global characteristics such as drag coefficients and average Nusselt number, etc. are calculated and the representative streamline and isotherm contours are presented for the above range of conditions. It has been found that the individual and overall drag coefficients decrease and the average Nusselt number increases with Reynolds number for all T / D and n considered here. The heat transfer is found higher in shear-thinning fluids than Newtonian fluids and followed by shear-thickening fluids for 1.5 ⩽ T / D ⩽ 4.0 and 1 ⩽ Re ⩽ 40.

Two-dimensional unconfined flow and heat transfer across a long tapered trapezoidal bluff body are investigated for the range Re = 1 to 150 (thereby covering both steady and unsteady periodic regimes) and Pr = 0.7 (air). A number of engineering parameters, e.g. drag and lift coefficients, Strouhal and Nusselt numbers, and others, is calculated for the above range of conditions. No flow separation occurs from the surface of the trapezoidal cylinder for the range Re ≤ 5; however, flow starts to separate from the rear surface of the cylinder at Re = 6. Therefore, the onset of flow separation exits between Re = 5 and 6. The critical value of the Reynolds number (i.e. transition from steady to unsteady) exists between Re = 46 and 47. The drag coefficient decreases with increasing Reynolds number in the steady regime; however, the drag increases with Reynolds number in the unsteady regime. The Strouhal number and the average Nusselt number increase with increasing value of the Reynolds number. Finally, the simple correlation for the average Nusselt number is obtained in the steady flow regime. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

The effects of agitation and aeration rates on copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] production by Azohydromonas lata MTCC 2311 using cane molasses supplemented with propionic acid in a bioreactor were investigated. The experiments were conducted in a three-level factorial design by varying the impeller (150–500 rev min−1) and aeration (0.5–1.5 vvm) rates. Further, the data were fitted to mathematical models [quadratic polynomial equation and artificial neural network (ANN)] and process variables were optimized by genetic algorithm-coupled models. ANN and hybrid ANN-GA were found superior for modeling and optimization of process variables, respectively. The maximum copolymer concentration of 7.45 g l−1 with 21.50 mol% of 3HV was predicted at process variables: agitation speed, 287 rev min−1; and aeration rate, 0.85 vvm, which upon validation gave 7.20 g l−1 of P(3HB-co-3HV) with 21 mol% of 3HV with the prediction error (%) of 3.38 and 2.32, respectively. Agitation speed established a relative high importance of 72.19% than of aeration rate (27.80%) for copolymer accumulation. The volumetric gas–liquid mass transfer coefficient (k L a) was strongly affected by agitation and aeration rates. The highest P(3HB-co-3HV) productivity of 0.163 g l−1 h−1 was achieved at 0.17 s−1 of k L a value. During the early phase of copolymer production process, 3HB monomers were accumulated, which were shifted to 3HV units (9–21%) during the cultivation period of 24–42 h. The enhancement of 7.5 and 34% were reported for P(3HB-co-3HV) production and 3HV content, respectively, by hybrid ANN-GA paradigm, which revealed the significant utilization of cane molasses for improved copolymer production.

Flow of non-Newtonian power-law fluids across a long circular bluff body confined symmetrically between infinitely long two parallel plane walls is investigated numerically by solving the continuity and momentum equations using the finite volume method–based solver Fluent. The numerical calculations are performed in the full computational domain for the following ranges: Reynolds number = 50–150 and power-law index = 0.4–1.8 (covering shear-thinning, Newtonian, and shear-thickening behaviors) for the blockage ratio of 0.25. Global characteristics such as drag and lift coefficients, and Strouhal number and derived variables such as stream function are calculated for the above range of conditions. It is observed that the shear-thinning behavior yields a lower value of the time-averaged drag coefficient than the corresponding Newtonian value; however, an opposite trend is observed in the shear-thickening behavior. The Strouhal number increases with increasing Reynolds number for the fixed value of the power-...

The effects of blockage ratio on the combined free and forced convection from a long heated square obstacle confined in a horizontal channel are investigated in this work. The numerical computations are performed in the steady regime for Reynolds number = 1 - 30, Richardson number = 0 - 1 for blockage ratios of 0.125 and 0.25 for the fixed Prandtl number of 0.7 (air). The governing equations, along with appropriate boundary conditions, are solved by using a semi-explicit finite volume method implemented on the collocated grid arrangement. The total drag and lift coefficients, local and average Nusselt numbers and the representative streamline, vorticity and isotherm patterns are presented to elucidate the role of blockage ratio on the cross-buoyancy across a confined square cylinder. The asymmetry in the flow and temperature fields decreases with increasing value of the blockage ratio. Similar to forced convection, the total drag coefficient increases with increasing value of the blockage ratio for the fixed values of the Reynolds and Richardson numbers.

In this paper, mixed convection flow and heat transfer around a long cylinder of square cross-section under the influence of aiding buoyancy are investigated in the vertical unconfined configuration (Reynolds number, Re = 1–40 and Richardson number, Ri = 0–1). The semi-explicit finite volume method implemented on the collocated grid arrangement is used to solve the governing equations along with the appropriate boundary conditions. The onset of flow separation occurs between Re = 1–2, between Re = 2–3 and between Re = 3–4 for Ri = 0, 0.5 and 1, respectively. The flow is found to be steady for the range of conditions studied here. The friction, pressure and total drag coefficients are found to increase with Richardson number, i.e., as the influence of aiding buoyancy increases drag coefficients increase at the constant value of the Reynolds number. The temperature field around the obstacle is presented by isotherm contours at the Prandtl number of 0.7 (air). The local and average Nusselt numbers are calculated to give a detailed study of heat transfer over each surface of the square cylinder and an overall heat transfer rate and it is found that heat transfer increases with increase in Reynolds number and/or Richardson number. The simple expressions for the wake length and average cylinder Nusselt number are obtained for the range of conditions covered in this work.

Composite cylindrical containers are broadly used in many industries for storage and transport of hazardous materials. The focus of this study is to evaluate the performance of thermal protection layer in different fire situations likely to be encountered during an accident and to minimize the risk of loss of containment. Flame temperature is simulated based on temperature–time curve used in furnace test. The developed model for transient heat conduction in composite cylinder consisting of three layers is investigated using Crank–Nicholson finite difference method (FDM) with inclusion of temperature dependent thermal conductivity. Normal and worst case scenarios have been considered and the performance of non-ablative type thermal protection layer evaluated. Rigid foam type thermal protection layer made of different materials is considered and changes in their density (50–200 kg/m3), conductivity (0.05–0.15 W/m K), temperature dependent conductivity and thickness of thermal protection layer (100–250 mm) on temperature profile are demonstrated for a pool fire simulating standard temperature–time curve. Variation of temperature with elapsed time at the interface between material and inner wall of the cylinder has been plotted for different thickness of protective layer (100–250 mm) which provides the vital information for preliminary assessment of protective layer thickness required to limit the temperature at the interface for the given time of exposure to fire and prevents the failure of cylindrical container.

The current study investigates the augmentation in the laminar forced convection characteristics of the backward-facing step flow in a two-dimensional channel by means of introducing an adiabatic circular cylinder in the domain. The effects of various cross-stream positions (i.e., yc = 0–1.5) of the circular cylinder on the flow and heat transfer characteristics of the backward-facing step flow has been numerically explored for the Reynolds number range 1–200 and Prandtl number of 0.71 (air). The governing continuity, Navier–Stokes and energy equations along with appropriate boundary conditions are solved by using FLUENT. The flow and thermal fields have been explained by streamline and isotherm profiles, respectively; however, no temperature dependency effects are considered for the flow viscosity and thermal conductivity. The engineering parameters like wake/recirculation length, total drag coefficient and average Nusselt number, etc. are calculated for the above range of conditions. The present results show an enhancement in the peak Nusselt value of up to 155% using a circular cylinder as compared to the unobstructed case (i.e., without cylinder). Finally, simple correlations for total drag coefficient and peak Nusselt number are obtained for the above range of conditions.

The present work describes the optimization of medium variables for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] by Azohydromonas lata MTCC 2311 using cane molasses supplemented with propionic acid. Genetic algorithm (GA) has been used for the optimization of P(3HB-co-3HV) production through the simulation of artificial neural network (ANN) and response surface methodology (RSM). The predictions by ANN are better than those of RSM and in good agreement with experimental findings. The highest P(3HB-co-3HV) concentration and 3HV content have been reported as 7.35 g/l and 16.84 mol%, respectively by hybrid ANN–GA. Upon validation, 7.20 g/l and 16.30 mol% of P(3HB-co-3HV) concentration and 3HV content have been found in the shake flask, whereas 6.70 g/l and 16.35 mol%, have been observed in a 3 l bioreactor, respectively. The specific growth rate and P(3HB-co-3HV) accumulation rate of 0.29 per h and 0.16 g/l h determined with cane molasses are comparable to those observed on pure substrates.

In this work, effects of Prandtl number on the heat transfer characteristics of an unconfined rotating circular cylinder are investigated for varying rotation rate (? = 0 - 5) in the Reynolds number range 1 - 35 and Prandtl numbers range 0.7 - 100 in the steady flow regime. The numerical calculations are carried out by using a finite volume method based commercial CFD solver FLUENT. The isotherm patterns are presented for varying values of Prandtl number and rotation rate in the steady regime. The variation of the local and the average Nusselt numbers with Reynolds number, Prandtl number and rotation rate are presented for the above range of conditions. The average Nusselt number is found to decrease with increasing value of the rotation rate for the fixed value of the Reynolds and Prandtl numbers. With increasing value of the Prandtl number, the average Nusselt number increases for the fixed value of the rotation rate and the Reynolds number; however, the larger values of the Prandtl numbers show a large reduction in the value of the average Nusselt number with increasing rotation rate.

In the present study, the maximum biomass and polyhydroxybutyrate productions were studied and optimized using suitable carbon and nitrogen sources by bacterial strain Azohydromonas lata MTCC 2311. Among three carbon sources namely, sucrose, fructose, and glucose and four nitrogen sources namely, (NH4)2SO4, NH4Cl, urea, and NH4NO3 studied in shake flask experiments, sucrose and urea were found to be the best carbon and nitrogen sources, respectively. Further, response surface methodology (RSM) and artificial neural network models (ANN) were applied to navigate the experimental data obtained in accordance with the central composite design. The effects of sucrose (3.2–36.82 g/L), urea (0.16–1.84 g/L), and TE solution (0.32–3.68 ml/L) on biomass and PHB concentrations were investigated. The modeling and optimization ability of hybrid ANN-GA had shown higher accuracy in finding optimum concentrations of medium variables than hybrid RSM-GA. Hybrid ANN-GA predicted the maximum biomass concentration (12.25 g/L) at the optimum level of medium variables: sucrose, 35.27 g/L; urea, 1.55 g/L; and TE solution, 0.42 ml/L. Whereas, the maximum predicted PHB concentration (5.95 g/L) was reported at: sucrose, 35.20 g/L; urea, 1.58 g/L; and TE solution, 0.36 ml/L. The validation with additional set of data shows that the predictive errors (%) in biomass and PHB concentrations were 3.67 and 2.52, respectively for shake flask experiments, whereas, the predictive errors (%) were 13.80 and 14.28, respectively, for bioreactor experiments.

Effects of Reynolds number on the heat transfer characteristics of a long (heated) equilateral triangular cylinder are investigated for the range of conditions Re = 50–150 (in the steps of 10) and Prandtl number = 0.71 (air) in the unconfined unsteady cross-flow regime. In order to simulate the present situation, the computational grid is created by using commercial grid generator GAMBIT and the numerical computations are carried out by using FLUENT (6.3). The SIMPLE method is used to solve continuity, Navier-Stokes and energy equations along with the appropriate boundary conditions. The second order upwind scheme is used to discretize the convective terms, while the central difference scheme is used to discretize the diffusive terms in the governing equations. The present results are in an excellent agreement with the literature values. The temperature isotherms and temporal history of Nusselt number are presented in detail. The local as well as time-averaged Nusselt numbers are calculated. The time-averaged Nusselt number increases with increasing Reynolds number for the fixed value of the Prandtl number. Finally, the present numerical results are used to develop the simple heat transfer correlation for the range of conditions covered here.

In this paper, fluid flow and heat transfer across a long equilateral triangular cylinder placed in a horizontal channel is studied for Reynolds number range 1–80 (in the steps of 5) and Prandtl number of 0.71 for a fixed blockage ratio of 0.25. The governing Navier-Stokes and energy equations along with appropriate boundary conditions are solved by using a commercial CFD solver FLUENT (6.3). The computational grid is created in a commercial grid generator GAMBIT. The flow and temperature fields are presented by stream-line and isotherm profiles, respectively. The wake/recirculation length, mean drag coefficient and average Nusselt number, etc. are calculated for the above range of conditions studied here. The critical value of the Reynolds number (i.e., transition to transient) is found to lie between Re = 58 and Re = 59. The average Nusselt number and the wake length increase with increasing value of the Reynolds number; however, the mean drag coefficient decreases with increasing value of the Reynolds number. Finally, simple correlations for wake length, mean drag coefficient and average Nusselt number are obtained for the range of conditions studied here.

In this research article, we have analyzed the effect of thermal stratification of shear layers due to mixed convection heat transfer past a pair of side-by-side square cylinders in a confined domain, an extended part of our recent study [A. Sanyal and A. Dhiman, “Wake interactions in a fluid flow past a pair of side-by-side square cylinders in presence of mixed convection,” Phys. Fluids 29, 103602 (2017)]. Investigations from the studies of instantaneous and time-averaged isotherms revealed the actual stretches of the temperature gradient in streamwise and transverse extents at Re = 1–40, Ri = 0–1, s/d = 0.7–10, and Pr = 50. The effects of “baroclinic production,” embedded in the transport of vorticity, were rigorously analyzed through the determination of local period-averaged vorticity flux at a certain cross section in the near-field downstream. The study also revealed the underlying flow physics pertaining to the variations in period-averaged wall vorticity and the local Nusselt number. The transport of vorticity has been explained in terms of the vortex structure formulations, and because of the absence of any such similar studies for multiple bluff-body arrangements, the study has been thoroughly correlated from the cases of single bluff-body flow. In an attempt to control several flow regimes by slightly changing the flow and thermal parameters, it is found that chaotic flow cannot exist beyond a certain value of s/d. However, an abnormality was noted in terms of the flow bifurcations at s/d = 1.5 at the juncture of flow transition from unseparated to a separated steady flow for the first time and this is solely attributed to the effect of thermal buoyancy in the flow field.

In this study, heat transfer to power-law dilatant fluids from a long square cylinder (heated) confined in a channel in the steady flow regime is investigated. The effects of Reynolds number, Prandtl number and flow behavior index on the heat transfer characteristics of a cylinder is examined for the range of conditions 1 ⩽ Re ⩽ 45 , 1 ⩽ n ⩽ 2.0 and 1 ⩽ Pr ⩽ 100 (the maximum Peclet number being 4000) for a fixed blockage ratio, β = 1 / 8 . The variation of the local Nusselt number on the individual surfaces of the square obstacle for the constant wall temperature (CWT) and uniform heat flux (UHF) boundary conditions prescribed on the surface of the square obstacle are presented. Likewise, the representative isotherm plots for the two classical thermal boundary conditions are shown. The average Nusselt number and the heat transfer factor ( j h ) have also been calculated. Irrespective of the value of the flow behavior index, the value of the local Nusselt number at each corner of the square cylinder increases with an increase in the Reynolds and/or Prandtl number. The average Nusselt number increases monotonically with an increase in the Reynolds and/or the Prandtl number. Finally, simple heat transfer correlations have been provided for the range of conditions covered here.

The effect of blockage ratio on the flow characteristics of power-law fluids across a square cylinder confined in a channel has been investigated for the range of conditions 1 ≤ Re ≤ 45, 0.5 ≤n ≤ 2.0 and β = 1/8, 1/6 and 1/4. Extensive numerical results on the individual and total drag coefficients, wake length, stream function, vorticity and power-law viscosity on the surface of the square cylinder are reported to determine the combined effects of the flow behavior index, blockage ratio and Reynolds number. The size of the wake region is influenced more by blockage than by power-law index. Similarly, drag is also seen to be more influenced by blockage ratio and the Reynolds number than that by the power-law index.

The effects of cross-buoyancy and of Prandtl number on the flow and heat transfer characteristics of an isothermal square cylinder confined in a channel has been investigated here. The numerical results have been presented for the range of conditions as: 1 ≤ Re ≤ 30, 0.7 ≤ Pr ≤ 100 (the maximum value of Peclet number being 3000) and 0 ≤ Ri ≤ 1for a fixed blockage ratio of 0.125. The overall drag and lift coefficients, local and average Nusselt numbers and the representative streamline and isotherm plots are presented to elucidate the role of Reynolds number, Prandtl number and Richardson number. The drag coefficient is found to be less sensitive to the Richardson number than the lift coefficient.

Forced-convection heat transfer to power-law fluids from a heated square cylinder has been investigated numerically for the range of conditions 1 ≤ Re ≤ 45, 0.5 ≤ n ≤ 2.0 and 1 ≤ Pr ≤ 100 (the maximum Peclet number being 4,000). In this range of Reynolds number, the flow is known to be steady and two-dimensional. The variation of the local Nusselt number on the individual surfaces of the square cylinder and the representative isotherm plots, for both the constant-temperature and uniform-heat-flux boundary conditions prescribed on the surface of the square obstacle, are presented to elucidate the role of Reynolds number, Prandtl number, and power-law index on the heat transfer characteristics. Using the present numerical data, appropriate predictive correlations are obtained for estimating the value of the mean heat transfer coefficient in a new application.

Politics is a bane of administrative systems such as performance appraisals. It not only debilitates the system's credibility in the eyes of various stakeholders, but also adversely affects the employees' morale and the organizational effectiveness. While admitting that rooting it out completely is impossible, it is in the organizational interest that it is mitigated to a large extent. In case of performance appraisals, assessees and assessors, both try to influence the assessees� performance rating to advance self-interests. The former typically aims at higher ratings/rewards, and uses informal influence means such as upward connections, ingratiation, etc., to achieve it. The latter may use appraisals to fulfil their vested interests like building in�groups by rewarding certain favoured assessees, and projecting good departmental performance, by manipulating assessees� ratings (inflation or deflation). Some managers consider these actions legitimate because it helps them manage effectively. While these manipulations may fulfil the assessors' short-term goals, it hurts the organization in the long run by compromising performance culture, demoralizing genuine performers, discrediting pay for performance policies, etc. This paper focuses on the assessors' perspective and conceptualizes their perceptions of politics in appraisals (PAPS). We argue that PAPS constitutes the assessors' perception about political behaviours of other stakeholders�reviewers, assessees, and fellow appraisers�and shapes their own perceptions. These perceptions will be influenced by certain contextual factors in which appraisals are conducted. We have focused on four such factors: ambiguity about policies, procedures, performance standards, criteria, etc. assessors' accountability with respect to appraisals assessors' and assessees' instrumentality linked to appraisal organizational support in terms of assessors� training to conduct better appraisals. We argue that these are key variables closely related to many job and organizational characteristics, and thus are fair representation of the appraisal context. In relation to these antecedents, we propose that these reduce assessors� PAPS when: Appraisal process and system ambiguity is low. The assessors are accountable to a neutral authority for following appraisal procedures which enhance rating accuracy; on the other hand, assessors' outcome accountability accentuates politicking. Some of the procedures which enhance accuracy are frequent feedback, 360-degree feedback, assessees' involvement in the process, etc. The assessors are trained to conduct fair appraisals. The assessors' and the assessees' appraisal instrumentality directly affects PAPS as well as moderates the above relations. It is further proposed that PAPS predict the assessors' intentions to pursue certain appraisal goals. It can be rating accuracy if political perceptions are low; and, it can be other political goals, if these perceptions are high. These intentions predict actual assessor actions. This paper contributes to appraisal literature and informs managers about mitigating appraisal politics.