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Sample records for horizontal microfin tubes

  1. Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoyan [School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-11-15

    Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes. (author)

  2. Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoyan, Zhang [School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)], E-mail: gqzxy@sohu.com; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-11-15

    Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes.

  3. Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

    International Nuclear Information System (INIS)

    Zhang Xiaoyan; Yuan Xiuling

    2008-01-01

    Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30-50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes

  4. Experimental Study of Flow Boiling Heat Transfer in a Horizontal Microfin Tube

    OpenAIRE

    Yu, Jian; Koyama, Shigeru; Momoki, Satoru

    1995-01-01

    An experimental study on flow boiling heat transfer in a horizontal microfin tube is conducted with pure refrigerants HFC134a, HCFC123 and HCFC22 using a water-heated double-tube type test section. The test microfin tube is a copper tube having the following dimensions: 8.37mm mean inside diameter, 0.168mm fin height, 60fin number and 18 degree of helix angle. The local heat transfer coefficients for both counter and parallel flows are measured in a range of heat flux of 1 to 93W/m^2, mass ve...

  5. Heat transfer performance during in-tube condensation in horizontal smooth, micro-fin and herringbone tubes

    OpenAIRE

    2008-01-01

    M.Ing. An experimental investigation was conducted into the heat transfer characteristics of horizontal smooth, micro-fin and herringbone tubes during in-tube condensation. The study focused on the heat transfer coefficients of refrigerants R-22, R-134a and R-407C inside the three tubes. The herringbone tube results were compared to the smooth and micro-fin tube results. The average increase in the heat transfer coefficient when compared to the smooth tube was found to be as high as 322% w...

  6. Theoretical study of evaporation heat transfer in horizontal microfin tubes: stratified flow model

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H; Wang, Y S [Kyushu Univ., Inst. for Materials Chemistry and Engineering, Kasuga, Fukuoka (Japan)

    2004-08-01

    The stratified flow model of evaporation heat transfer in helically grooved, horizontal microfin tubes has been developed. The profile of stratified liquid was determined by a theoretical model previously developed for condensation in horizontal microfin tubes. For the region above the stratified liquid, the meniscus profile in the groove between adjacent fins was determined by a force balance between the gravity and surface tension forces. The thin film evaporation model was applied to predict heat transfer in the thin film region of the meniscus. Heat transfer through the stratified liquid was estimated by using an empirical correlation proposed by Mori et al. The theoretical predictions of the circumferential average heat transfer coefficient were compared with available experimental data for four tubes and three refrigerants. A good agreement was obtained for the region of Fr{sub 0}<2.5 as long as partial dry out of tube surface did not occur. (Author)

  7. Condensation heat transfer of R22 and R410A in horizontal smooth and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Man-Hoe; Shin, Joeng-Seob [Korea Advanced Institute of Science and Technology, Daejeon (Korea). Department of Mechanical Engineering

    2005-09-01

    An experimental investigation of condensation heat transfer in 9.52 mm O.D. horizontal copper tubes was conducted using R22 and R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was cooled by the heat transfer fluid (cold water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained throughout the experiment and refrigerant quality varied from 0.9 to 0.1. The condensation test results at 45 {sup o}C were reported for 40-80 kg/h mass flow rate. The local and average condensation coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average condensation coefficients of R22 and R410A for the microfin tubes were 1.7-3.19 and 1.7-2.94 times larger than those in smooth tube, respectively. (author)

  8. Evaporating heat transfer of R22 and R410A in horizontal smooth and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Man-Hoe; Shin, Joeng-Seob [Korea Advanced Institute of Science and Technology, Daejeon (Korea). Department of Mechanical Engineering

    2005-09-01

    An experimental investigation of evaporating heat transfer in 9.52 mm O.D. horizontal copper tubes was conducted. The refrigerants tested were R22 and the near-azeotropic mixture, R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was heated by the heat transfer fluid (hot water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained and refrigerant quality varied from 0.2 to 0.8.. The results were reported for evaporation at 15 {sup o}C in a 0.92 m long test section for 30-60 kg/h mass flow rate. The local and average heat transfer coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average evaporation heat transfer coefficients of R22 and R410A for the microfin tubes were 1.86-3.27 and 1.64-2.99 times higher than those for the smooth tube, respectively. When compared to R22 at the same test conditions, the evaporating heat transfer coefficients for R410A were 97-129% of R22. (author)

  9. Theoretical analysis of film condensation in horizontal microfin tubes; Microfin tsuki suihei kannai gyoshuku no riron kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H; Wang, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Nozu, S [Okamaya Prefectural University, Okayama (Japan). Faculty of Computer Science and System Engineering

    2000-10-25

    A theoretical study has been made of film condensation in helically-grooved, horizontal microfin tubes. The annular flow regime and the stratified flow regime were considered. For the annular flow regime, a previously developed theoretical model was applied. For the stratified flow regime, the height of stratified condensate was estimated by a modified Taitel and Dukler model. For the upper part of the tube exposed to the vapor flow, numerical calculation of Laminar film condensation considering the combined effects of gravity and surface tension forces was conducted. The heat transfer coefficient at the lower part of the tube was estimated by an empirical equation for the internally finned tubes developed by Carnavos. The theoretical predictions of the circumferential average heat transfer coefficient by the two theoretical models were compared with available experimental data for four refrigerants and four tubes. Generally, the annular flow model gave a higher heat transfer coefficient than the stratified flow model in the high quality region, whereas the stratified flow model gave a higher heat transfer coefficient in the low quality region. For tubes with fin heights of 0.16 {approx} 0.24 mm, most of the experimental data agreed within {+-} 20% with the higher of the two theoretical predictions. (author)

  10. Condensation of refrigerants in horizontal microfin tubes: comparison of prediction methods for heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H S; Honda, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    2003-06-01

    A comparison was made between the predictions of previously proposed empirical correlations and theoretical model and available experimental data for the heat transfer coefficient during condensation of refrigerants in horizontal microfin tubes. The refrigerants tested were R11, R123, R134a, R22 and R410A. Experimental data for six tubes with the tube inside diameter at fin root of 6.49-8.8 8 mm, the fin height of 0.16-0.24 mm, fin pitch of 0.34-0.53 mm and helix angle of groove of 12-20{sup o} were adopted. The r.m.s. error of the predictions for all tubes and all refrigerants decreased in the order of the correlations proposed by Luu and Bergies [ASHRAE Trans. 86 (1980) 293], Cavallini et al. Condensation of new refrigerants inside smooth and enhanced tubes. In: Proc. 19th Int. Cong. Refrigeration, vol. IV, Hague, The Netherlands, 1995. p. 105-114, Shikazono et al. [Trans. Jap. Sco. Mech. Engrs. 64 (1995) 196], Kedzierski and Goncalves [J. Enhanced Heat Transfer 6 (1999) 16], Yu and Koyama [Yu J, Koyama S. Condensation heat transfer of pure refrigerants in microfin tubes. In: Proc. Int. Refrigeration Conference at Purdue Univ., West Lafayette, USA, 1998. p. 325-330], and the theoretical model proposed by Wang et al. [Int. J. Heat Mass Transfer 45 (2002) 1513]. (author)

  11. New Correlation Methods of Evaporation Heat Transfer in Horizontal Microfine Tubes

    Science.gov (United States)

    Makishi, Osamu; Honda, Hiroshi

    A stratified flow model and an annular flow model of evaporation heat transfer in horizontal microfin tubes have been proposed. In the stratified flow model, the contributions of thin film evaporation and nucleate boiling in the groove above a stratified liquid were predicted by a previously reported numerical analysis and a newly developed correlation, respectively. The contributions of nucleate boiling and forced convection in the stratified liquid region were predicted by the new correlation and the Carnavos equation, respectively. In the annular flow model, the contributions of nucleate boiling and forced convection were predicted by the new correlation and the Carnavos equation in which the equivalent Reynolds number was introduced, respectively. A flow pattern transition criterion proposed by Kattan et al. was incorporated to predict the circumferential average heat transfer coefficient in the intermediate region by use of the two models. The predictions of the heat transfer coefficient compared well with available experimental data for ten tubes and four refrigerants.

  12. Evaporation of R134a in a horizontal herringbone microfin tube: heat transfer and pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Wellsandt, S; Vamling, L [Chalmers University of Technology, Gothenburg (Sweden). Department of Chemical Engineering and Environmental Science, Heat and Power Technology

    2005-09-01

    An experimental investigation of in-tube evaporation of R134a has been carried out for a 4 m long herringbone microfin tube with an outer diameter of 9.53 mm. Measured local heat transfer coefficients and pressure losses are reported for evaporation temperatures between -0.7 and 10.1 {sup o}C and mass flow rates between 162 and 366 kg m{sup -2} s{sup -1}. Results from this work are compared to experimental results from literature as well as predicted values from some available helical microfin correlations. Differences in heat transfer mechanisms between helical and herringbone microfin tubes are discussed, as heat transfer coefficients in the investigated herringbone tube tend to peak at lower vapour qualities compared to helical microfins. Correlations developed for helical microfin tubes generally predict experimental values within {+-}30% for vapour qualities below 50%. However, at higher qualities none of the correlations are able to reflect the early peak of heat transfer coefficients. Predicted pressure gradients reproduce measured values in general within {+-}20%. (author)

  13. Experimental Study on Flow Boiling of Carbon Dioxide in a Horizontal Microfin Tube

    Science.gov (United States)

    Kuwahara, Ken; Ikeda, Soshi; Koyama, Shigeru

    This paper deals with the experimental study on flow boiling heat transfer of carbon dioxide in a micro-fin tube. The geometrical parameters of micro-fin tube used in this study are 6.07 mm in outer diameter, 5.24 mm in average inner diameter, 0.256 mm in fin height, 20.4 in helix angle, 52 in number of grooves and 2.35 in area expansion ratio. Flow patterns and heat transfer coefficients were measured at 3-5 MPa in pressure, 300-540 kg/(m2s) in mass velocity and -5 to 15 °C in CO2 temperature. Flow patterns of wavy flow, slug flow and annular flow were observed. The measured heat transfer coefficients of micro-fin tube were 10-40 kW/(m2K). Heat transfer coefficients were strongly influenced by pressure.

  14. Prediction of effective friction factors for single-phase flow in horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H S; Rose, J W [University of London (United Kingdom). Queen Mary, Department of Engineering

    2004-12-01

    An experimental database, covering a wide range of tube and fin geometric dimensions, Reynolds number and including data for water, R11, and ethylene glycol has been compiled for friction factor for single-phase flow in spirally grooved, horizontal microfin tubes. The tubes (21 in all) had inside diameter at the fin root between 6.46 and 24.13 mm, fin height between 0.13 and 0.47 mm, fin pitch between 0.32 and 1.15 mm, and helix angle between 17 and 45 degrees. The Reynolds number ranged from 2.0x10{sup 3} to 1.63x10{sup 5}. Six earlier friction factor correlations, each based on restricted data sets, have been compared with the database as a whole. None was found to be in good agreement with all of the data. The Jensen and Vlakancic correlation was found to be the best and represents the database within {+-}21%. (author)

  15. Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

    Science.gov (United States)

    Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

    This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

  16. R404A condensing under forced flow conditions inside smooth, microfin and cross-hatched horizontal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Infante Ferreira, C A; Nan, X [Delft University of Technology (Netherlands). Laboratory for Refrigeration and Indoor Climate Control; Newell, T A; Chato, J C [University of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

    2003-06-01

    Two-phase heat transfer coefficient characteristics of R404A condensing under forced flow conditions inside smooth, microfin and cross-hatched horizontal tubes are experimentally investigated. Experimental parameters include a lubricating polyol ester oil concentration varied from 0 to 4%. The test runs were done at average inlet saturated condensing temperatures of 40{sup o}C. The inlet vapor was kept at saturation (quality = 1.0). The mass fluxes were between 200 and 600 kg/m{sup 2}s, and the heat fluxes were selected to obtain a quality of 0.0 at the outlet of the test section, varying from 5 to 45 kW/m{sup 2}. The heat transfer enhancement factor varied between 1.8 and 2.4 for both microfin and cross-hatched tubes. The larger values applied for larger mass fluxes for the cross-hatched tube and smaller mass fluxes for the microfin tube. Enhancement factors increased as oil concentration increased up to oil concentrations of 2%. For higher oil concentrations the enhancement decreased especially at high mass fluxes, the cross-hatched tube being less sensitive to oil contamination. Pressure drop in the test section increased by approximately 25% as the oil concentration increased from 0 to 4%. The results from the experiments are compared with those calculated from correlations reported in the literature. Moreover, modified correlations for the condensation heat transfer coefficient are proposed for practical applications. (author)

  17. Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

    2010-11-15

    Flow condensation pressure drop characteristics of R410A-oil mixture inside small diameter (5.0 mm and 4.0 mm O.D.) horizontal microfin tubes were investigated experimentally covering nominal oil concentrations from 0% to 5%. The research results indicate that, comparing with the frictional pressure drop of pure R410A, the frictional pressure drop of R410A-oil mixture may decrease by maximum of 18% when the vapor quality is lower than 0.6, and increase by maximum of 13% when the vapor quality is higher than 0.6. A new frictional pressure drop correlation for R410A-oil mixture flow condensation inside microfin tubes is developed based on the refrigerant-oil mixture properties, and can agree with 94% of the experimental data within a deviation of -30% to +30%. (author)

  18. Condensation of refrigerants in horizontal, spirally grooved microfin tubes: Numerical analysis of heat transfer in the annular flow regime

    Energy Technology Data Exchange (ETDEWEB)

    Nozu, S; Honda, H

    2000-02-01

    A method is presented for estimating the condensation heat transfer coefficient in a horizontal, spirally grooved microfin tube. Based on the flow observation study performed by the authors, a laminar film condensation model in the annular flow regime is proposed. The model assumes that all the condensate flow occurs through the grooves. The condensate film is segmented into thin and thick film regions. In the thin film region formed on the fin surface, the condensate is assumed to be drained by the combined surface tension and vapor shear forces. In the thick film region formed in the groove, on the other hand, the condensate is assumed to be driven by the vapor shear force. The present and previous local heat transfer data including four fluids (CFC11, HCFC22, HCFC123, and HFCl34a) and three microfin tubes are found to agree with the present predictions to a mean absolute deviation of 15.1%.

  19. Heat and mass transfer prediction of binary refrigerant mixtures condensing in a horizontal microfin tube

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Shigeru; Yu, Jian; Ishibashi, Akira

    1999-07-01

    In the face of the phase-out of HCFC22 for its effect on globe environment, the alternative refrigerant has been paid attention in the refrigeration and heat pump industry. In the present stage, it is found that any pure refrigerant is not a good substitute of HCFC22 for the system in use. The authors have to use binary or ternary refrigerant mixtures as the substitute to meet industrial requirement. But until now, although the heat transfer characteristics of the refrigerant mixtures can be measured in experiments and predicted in some degree, the mass transfer characteristics in condensation process, which is a main part in most systems, can not be clarified by both experimental and theoretical methods. In the present study a non-equilibrium model for condensation of binary refrigerant mixtures inside a horizontal microfin tube is proposed. In this model it is assumed that the phase equilibrium is only established at the vapor-liquid interface, while the bulk vapor and the bulk liquid are in non-equilibrium in the same cross section. The mass transfer characteristic in vapor core is obtained from the analogy between mass and momentum transfer. In the liquid layer, the mass fraction distribution is neglected, but the mass transfer coefficient is treated as infinite that can keep a finite value for the mass transfer rate in liquid phase. From the calculation results compared with the experimental ones for the condensation of HFC134a/HCFC123 and HCFC22/CFC114 mixtures, it is found that the calculated heat flux distribution along the tube axis is in good agreement with that of experiment, and the calculated values of condensing length agree well with the experimental ones. Using the present model, the local mass faction distribution, the diffusion mass transfer rate and the mass transfer characteristics in both vapor and liquid phase are demonstrated. From these results, the effect of mass transfer resistance on condensation heat transfer characteristics for binary

  20. Heat transfer, pressure drop and flow patterns during flow boiling of R407C in a horizontal microfin tube

    Science.gov (United States)

    Rollmann, P.; Spindler, K.; Müller-Steinhagen, H.

    2011-08-01

    The heat transfer, pressure drop and flow patterns during flow boiling of R407C in a horizontal microfin tube have been investigated. The microfin tube is made of copper with a total fin number of 55 and a helix angle of 15°. The fin height is 0.24 mm and the inner tube diameter at fin root is 8.95 mm. The test tube is 1 m long. It is heated electrically. The experiments have been performed at saturation temperatures between -30°C and +10°C. The mass flux was varied between 25 and 300 kg/m2/s, the heat flux from 20,000 W/m2 down to 1,000 W/m2. The vapour quality was kept constant at 0.1, 0.3, 0.5, 0.7 at the inlet and 0.8, 1.0 at the outlet, respectively. The measured heat transfer coefficient is compared with the correlations of Cavallini et al., Shah as well as Zhang et al. Cavallini's correlation contains seven experimental constants. After fitting these constants to our measured values, the correlation achieves good agreement. The measured pressure drop is compared to the correlations of Pierre, Kuo and Wang as well as Müller-Steinhagen and Heck. The best agreement is achieved with the correlation of Kuo and Wang. Almost all values are calculated within an accuracy of ±30%. The flow regimes were observed. It is shown, that changes in the flow regime affect the heat transfer coefficient significantly.

  1. Experimental study of the condensation heat transfer characteristics of CO2 in a horizontal microfin tube with a diameter of 4.95 mm

    Science.gov (United States)

    Son, Chang-Hyo; Oh, Hoo-Kyu

    2012-11-01

    The condensation heat transfer characteristics for CO2 flowing in a horizontal microfin tube were investigated by experiment with respect to condensation temperature and mass flux. The test section consists of a 2,400 mm long horizontal copper tube of 4.6 mm inner diameter. The experiments were conducted at refrigerant mass flux of 400-800 kg/m2s, and saturation temperature of 20-30 °C. The main experimental results showed that annular flow was highly dominated the majority of condensation flow in the horizontal microfin tube. The condensation heat transfer coefficient increases with decreasing saturation temperature and increasing mass flux. The experimental data were compared against previous heat transfer correlations. Most correlations failed to predict the experimental data. However, the correlation by Cavallini et al. showed relatively good agreement with experimental data in the microfin tube. Therefore, a new condensation heat transfer correlation is proposed with mean and average deviations of 3.14 and -7.6 %, respectively.

  2. Evaporation of R407C and R410A in a horizontal herringbone microfin tube: heat transfer and pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Wellsandt, S; Vamling, L [Chalmers University of Technology, Gothenburg (Sweden). Department of Chemical Engineering and Environmental Science, Heat and Power Technology

    2005-09-01

    An experimental investigation of in-tube evaporation of R410A and R407C has been carried out for a 4 m long herringbone microfin tube with an outer diameter of 9.53 mm. Measured local heat transfer coefficients and pressure losses are reported for evaporation temperatures for R410A and R407C between -2.2 and 9.5 {sup o}C and between -5.5 and 13.8 {sup o}C, respectively. Mass flow rates between 162 and 366 kg m{sup -2} s{sup -1} have been investigated. Results from this work are compared to R134a data from an earlier work by the present authors, and also to predicted values from some available helical microfin correlations. Compared to R134a data, heat transfer coefficients for the investigated mixtures are generally lower, especially at low mass flow rates. No major effect of heat flux on heat transfer coefficients was found, with the exception of the high quality region. Predicted heat transfer coefficients from helical microfin correlations strongly overpredict the present data. Global pressure losses are predicted well, even though local deviations are found. (author)

  3. Prediction of evaporation heat transfer coefficient based on gas-liquid two-phase annular flow regime in horizontal microfin tubes

    International Nuclear Information System (INIS)

    Wang Yueshe; Wang Yanling; Wang, G.-X.; Honda, Hiroshi

    2009-01-01

    A physical model of gas-liquid two-phase annular flow regime is presented for predicting the enhanced evaporation heat transfer characteristics in horizontal microfin tubes. The model is based on the equivalence of a periodical distortion of the disturbance wave in the substrate layer. Corresponding to the stratified flow model proposed previously by authors, the dimensionless quantity Fr 0 = G/[gd e ρ v (ρ l - ρ v )] 0.5 may be used as a measure for determining the applicability of the present theoretical model, which was used to restrict the transition boundary between the stratified-wavy flow and the annular/intermittent flows. Comparison of the prediction of the circumferential average heat transfer coefficient with available experimental data for four tubes and three refrigerants reveals that a good agreement is obtained or the trend is better than that of the previously developed stratified flow model for Fr 0 > 4.0 as long as the partial dry out of tube does not occur. Obviously, the developed annular model is applicable and reliable for evaporation in horizontal microfin tubes under the case of high heat flux and high mass flux.

  4. Prediction of evaporation heat transfer coefficient based on gas-liquid two-phase annular flow regime in horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yueshe, E-mail: wangys@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yanling, Wang [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, G -X [Mechanical Engineering Department, The University of Akron, Akron, OH 44325-3903 (United States); Honda, Hiroshi [Kyushu University, 337 Kasuya-machi, Kasuya-gun, Kukuoka 811-2307 (Japan)

    2009-10-15

    A physical model of gas-liquid two-phase annular flow regime is presented for predicting the enhanced evaporation heat transfer characteristics in horizontal microfin tubes. The model is based on the equivalence of a periodical distortion of the disturbance wave in the substrate layer. Corresponding to the stratified flow model proposed previously by authors, the dimensionless quantity Fr{sub 0} = G/[gd{sub e}{rho}{sub v}({rho}{sub l} - {rho}{sub v})]{sup 0.5} may be used as a measure for determining the applicability of the present theoretical model, which was used to restrict the transition boundary between the stratified-wavy flow and the annular/intermittent flows. Comparison of the prediction of the circumferential average heat transfer coefficient with available experimental data for four tubes and three refrigerants reveals that a good agreement is obtained or the trend is better than that of the previously developed stratified flow model for Fr{sub 0} > 4.0 as long as the partial dry out of tube does not occur. Obviously, the developed annular model is applicable and reliable for evaporation in horizontal microfin tubes under the case of high heat flux and high mass flux.

  5. Boiling and condensation in microfin tubes

    Science.gov (United States)

    Schlager, Lynn M.

    A general overview of microfin tubes and their applications is presented. Manufacturing processes, commercial availability, experimental heat transfer, and pressure drop data for various refrigerants (including alternative refrigerants and refrigerant-oil mixtures), physical mechanisms of enhancement, and the incorporation of microfin tubes in common heat exchanger configurations are discussed. Microfin tubes, also known by various trade names, are characterized by numerous small fins which typically spiral down the inside wall of tubes at angles ranging from 10 to 30 degrees. The number of fins ranges from 48 to 70 with typical fin heights of 0.12 to 0.30 mm (fin height generally less than 3 percent of the inside diameter of the tube). Fin shapes may vary and the inside surface area of microfin tubes is 10 to 70 percent greater than the area of equivalent smooth tubes. Heat transfer can be enhanced by up to a factor of three with microfin tubes.

  6. Condensation of refrigerant CFC 11 in horizontal microfin tubes. Proposal of a correlation equation for frictional pressure gradient; Reibai CFC11 no microfin tsuki suihei kannai gyoshuku. Atsuryoku koka no jikkenshiki no teian

    Energy Technology Data Exchange (ETDEWEB)

    Nozu, S [Univ. of Okayama Prefecture, Okayama (Japan); Katayama, H [Mitsubishi Chemical Co., Inc., Tokyo (Japan); Nakata, H [Daikin Industries, Ltd., Osaka (Japan); Honda, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1996-09-25

    Local heat transfer and pressure drop measurements were made during condensation of CFC 11 in microfin tubes. A smooth tube and two microfin tubes with different fin dimensions were used. Flow observation study with use of an industrial bore-scope revealed that the condensate swirled along the grooves, and a thick condensate film covered fins in the lower part of the tube in the low quality region. Static pressure gradients in the microfin tubes were up to 70 percent larger than that in a smooth tube. A correlation equation for the local frictional pressure gradient was derived, in which the effect of refrigerant mass velocity was introduced on the basis of the flow regime consideration. The measured frictional pressure gradient data were found by the present method to have a mean absolute deviation of 8.3 percent. 24 refs., 11 figs., 3 tabs.

  7. Condensation of refrigerants in horizontal microfin tubes. Numerical analysis of heat transfer for annular flow regime; Reibai no microfin tsuki suihei kannai gyoshuku. Kanjoryu ryoiki ni okeru netsudentatsu no suchi kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Nozu, S [Okayama Prefectural University, Okayama (Japan); Honda, H [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study

    1998-07-25

    A method for predicting the local heat transfer coefficient is presented for film condensation of vapor in a spirally grooved horizontal microfin-tube. Based on the flow observation study performed by the present authors, film flow model between fins in the annular flow regime is proposed. For the fin surface, laminar condensate film controlled by the combined effects of vapor shear and surface tension forces is analyzed. While, in the groove, thick condensate film driven by the vapor shear force is taken into consideration. A parameter which accounts for the transition from annular- to stratified flow regimes is also derived. The present and previous local heat transfer data for fluorocarbon refrigerants in the annular flow regime are found by the present numerical analysis to have a mean absolute deviation of 15.1 percent. 12 refs., 10 figs., 2 tabs.

  8. Heat transfer and flow pattern during two-phase flow boiling of R-134a in horizontal smooth and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Minghuei; Lin, Tsunkuo; Tseng, Chyuanchyi [National Sun Yat Sen Univ., Taiwan (China). Dept. of Mechanical Engineering

    2002-09-01

    Flow pattern and heat transfer during evaporation in a 10.7 mm diameter smooth tube and a micro-fin tube are presented. The tubes were tested in the ranges of mass flux between 163 and 408 kg m{sup -2}s{sup -1} and heat flux between 2200 and 56 000 W m{sup -2}. The evaporation temperature was 6{sup o}C. Flow maps for both the tubes are plotted in the coordinates of mass flux and vapor quality. The relations of flow pattern and local heat transfer coefficient are discussed. The heat transfer coefficients for intermittent and annular flows in both the smooth tube and the micro-fin tube are shown to agree well with Gungor and Winterton's correlation with modified constants. (author)

  9. Heat transfer during condensation of HFC-134a and R-404A inside of a horizontal smooth and micro-fin tube

    Energy Technology Data Exchange (ETDEWEB)

    Sapali, S N [Govt. College of Engineering, Department of Mechanical Engineering, Shivaji Nagar, Pune, Maharashtra 411 005 (India); Patil, Pradeep A [AISSMS College of Engineering, Pune University, Mechanical Engineering Department, Kennedy Road, Near R.T.O., Pune, Maharashtra 411 001 (India)

    2010-11-15

    In recent small and medium capacity refrigeration systems, the condenser tubes are provided with micro-fins from inside. The vapour refrigerant at the compressor outlet and the condenser inlet is in superheat state. As it advances in the condenser it is in two phases and at the outlet it is in sub cooled liquid. The heat transfer coefficient (HTC) during condensation of HFC-134a and R-404A in a smooth (8.56 mm ID) and micro-fin tubes (8.96 mm ID) are experimentally investigated. Different from previous studies, the present experiments are performed for various condensing temperatures, with superheating and sub cooling and using hermetically sealed compressor. The test runs are done at average saturated condensing temperatures ranging from 35 C to 60 C. The mass fluxes are between 90 and 800 kg m{sup -2} s{sup -1}. The experimental results indicate that the average HTC increases with mass flux but decreases with increasing condensing temperature for both smooth and micro-fin tubes. The average condensation HTCs of HFC-134a and R-404A for the micro-fin tubes were 1.5-2.5 and 1.3-2 times larger than that in smooth tube respectively. The HTCs for R-404A are less than that of HFC-134a. New correlations based on the data gathered during the experimentation for predicting condensation HTCs are proposed for wide range of operating conditions. (author)

  10. Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

    2010-10-15

    Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes were investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer. The deterioration effect is negligible at nominal oil concentration of 1%, and becomes obvious with the increase of nominal oil concentration. At 5% nominal oil concentration, the heat transfer coefficient of R410A-oil mixture is found to have a maximum reduction of 25.1% and 23.8% for 5 mm and 4 mm tubes, respectively. The predictabilities of the existing condensation heat transfer correlations were verified with the experimental data, and Yu and Koyama correlation shows the best predictability. By replacing the pure refrigerant properties with the mixture's properties, Yu and Koyama correlation has a deviation of -15% to + 20% in predicting the local condensation heat transfer coefficient of R410A-oil mixture. (author)

  11. Condensation of pure and near-azeotropic refrigerants in microfin tubes: A new computational procedure

    Energy Technology Data Exchange (ETDEWEB)

    Cavallini, A; Del Col, D; Mancin, S; Rossetto, L [Dipartimento di Fisica Tecnica, University of Padova, Via Venezia 1, Padova 35131 (Italy)

    2009-01-15

    Microfin tubes are widely used in air cooled and water cooled heat exchangers for heat pump and refrigeration applications during condensation or evaporation of refrigerants. In order to design heat exchangers and to optimize heat transfer surfaces, accurate procedures for computing pressure drops and heat transfer coefficients are necessary. This paper presents a new simple model for the prediction of the heat transfer coefficient to be applied to condensation in horizontal microfin tubes of halogenated and natural refrigerants, pure fluids or nearly azeotropic mixtures. The updated model accounts for refrigerant physical properties, two-phase flow patterns in microfin tubes and geometrical characteristics of the tubes. It is validated against a data bank of 3115 experimental heat transfer coefficients measured in different independent laboratories all over the world including diverse inside tube geometries and different condensing refrigerants among which R22, R134a, R123, R410A and CO{sub 2}. (author)

  12. A Correlation for Forced Convective Boiling Heat Transfer of Refrigerants in a Microfin Tube

    Science.gov (United States)

    Momoki, Satoru; Yu, Jian; Koyama, Shigeru; Fujii, Tetsu; Honda, Hiroshi

    The experimental study is reported on the forced convective boiling of pure refrigerants HCFC22, HFC134a and HCFC123 flowing in a horizontal microfin tube. The local heat transfer coefficient defined based on the actual inside surface area is measured in the ranges of mass velocity of 200 to 400 kg/m2s, heat flux of 5 to 64 kW/m2 and reduced pressure of 0.07 to 0.24. Using the Chen-type model, a new correlation for microfin tubes is proposed considering the enhancement effect of microfins on both the convective heat transfer and the nucleate boiling components. In the convective heat transfer component, the correlation to predict the heat transfer coefficient of liquid-only flow is determined from preliminary experiments on single-phase flow in microfin tubes, and the two-phase flow enhancement factor is determined from the present experimental data. For the nucleate boiling component, the correlation of Takamatsu et al. for smooth tube is modified. The prediction of the present correlation agrees well with present experimental data, and is available for several microfin tubes which were tested by other researchers.

  13. Effects of fin shape on condensation in herringbone microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Miyara, Akio [Saga University (Japan). Dept. of Mechanical Engineering; Otsubo, Yusuke; Ohtsuka, Satoshi; Mizuta, Yoshihiko [Saga University (Japan). Graduate School of Science and Engineering

    2003-06-01

    Effects of fin height and helix angle on condensation inside a herringbone microfin tube have been experimentally investigated with five types of herringbone microfin tubes. Heat transfer coefficients are about 2-4 times higher than that of the helical microfin tube under high mass velocity conditions. In the low mass velocity, they are equal to that of the helical microfin tube. The heat transfer enhancement increases with fin height up to 0.18 mm; higher fin heights show enhancement values similar to the 0.18 mm results. Pressure drop increases with the fin height. Larger helix angle yields higher heat transfer and higher pressure drop. For the lowest fin and/or smallest helix angle, the pressure drop is comparable with that of the helical microfin tube, while the heat transfer enhancement is higher. The enhancement mechanism is discussed from flow pattern observations. Effect of mass transfer resistance for R410A is estimated and negligible effects have been proved. (author)

  14. Vaporization inside a mini microfin tube: experimental results and modeling

    Science.gov (United States)

    Diani, A.; Rossetto, L.

    2015-11-01

    This paper proposes a comparison among the common R134a and the extremely low GWP refrigerant R1234yf during vaporization inside a mini microfin tube. This microfin tube has an internal diameter of 2.4 mm, it has 40 fins, with a fin height of 0.12 mm. Due to the high heat transfer coefficients shown by this tube, this technology can lead to a refrigerant charge reduction. Tests were run in the Heat Transfer in Micro Geometries Lab of the Dipartimento di Ingegneria Industriale of the Università di Padova. Mass velocities range between 375 and 940 kg m-2 s-1, heat fluxes from 10 to 50 kW m-2, vapour qualities from 0.10 to 0.99, at a saturation temperature of 30°C. The comparison among the two fluids is proposed at the same operating conditions, in order to highlight the heat transfer and pressure drop differences among the two refrigerants. In addition, two correlations are proposed to estimate the heat transfer coefficient and frictional pressure drop during refrigerant flow boiling inside mini microfin tubes. These correlations well predict the experimental values, and thus they can be used as a useful tool to design evaporators based on these mini microfin tubes.

  15. Experimental observation of two phase flow of R123 inside a herringbone microfin tube

    Science.gov (United States)

    Miyara, Akio; Islam, Mohammad Ariful; Mizuta, Yoshihiko; Kibe, Atsushi

    2003-08-01

    Vapor-liquid two phase flow behavior of R123 inside herringbone microfin tubes has been studied. Herringbone microfin tube is a kind of internally finned tube in which microfins are installed inside the tube where the microfins form multi-V-shape in flow direction. For the present experiment three different types of herringbone microfin tubes with helix angle β=8°, 14° and 28° are used. Experimental observations showed how flow diverges and converges inside herringbone microfin tube due to fin arrangement. The effect is more remarkable for larger helix angle. From the measurements of the cross-sectional liquid flow rate distribution, the liquid removal and collection and the entrained droplet are discussed. Quantity of liquid droplets is increased with increase of helix angle. The tube with helix angle β=28° shows higher quantity of liquid droplets than others.

  16. Heat transfer with geometric shape of micro-fin tubes (I) - Condensing heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, K M; Chang, J S; Bai, C H; Chung, M [Yeungnam University, Kyungsan (Korea)

    1999-11-01

    To examine the enhancement mechanism of condensing heat transfer through microfin tube, the condensation experiments with refrigerant HCFC 22 are performed using 4 and 6 kinds of microfin tubes with outer diameter of 9.52 mm and 7.0 mm, respectively. Used microfin tubes have different shape and number of fins with each other. The main heat transfer enhancement mechanism is known to be the enlargement of heat transfer area and turbulence promotion. Together with these main factors, we can find other enhancement factors by the experimental data, which are the overflow of the refrigerant over the microfin and microfin arrangement. The overflow of the refrigerant over the microfin can be analyzed by the geometric shape of the microfin. microfin tubes having a shape which can give much overflow over the microfin show large condensing heat transfer coefficients. The effect of microfin arrangement is related to the heat transfer resistance of liquid film of refrigerant. The condensing heat transfer coefficients are high for the microfin tube with even distribution of liquid film. 17 refs., 14 figs., 3 tabs.

  17. Experiment of flow regime map and local condensing heat transfer coefficients inside three dimensional inner microfin tubes

    Science.gov (United States)

    Du, Yang; Xin, Ming Dao

    1999-03-01

    This paper developed a new type of three dimensional inner microfin tube. The experimental results of the flow patterns for the horizontal condensation inside these tubes are reported in the paper. The flow patterns for the horizontal condensation inside the new made tubes are divided into annular flow, stratified flow and intermittent flow within the test conditions. The experiments of the local heat transfer coefficients for the different flow patterns have been systematically carried out. The experiments of the local heat transfer coefficients changing with the vapor dryness fraction have also been carried out. As compared with the heat transfer coefficients of the two dimensional inner microfin tubes, those of the three dimensional inner microfin tubes increase 47-127% for the annular flow region, 38-183% for the stratified flow and 15-75% for the intermittent flow, respectively. The enhancement factor of the local heat transfer coefficients is from 1.8-6.9 for the vapor dryness fraction from 0.05 to 1.

  18. Local heat transfer coefficients during boiling of R22 and R407C in horizontal smooth and microfin tubes; Coefficients d'echange locaux au cours de l'ebullition du R22 et du R407C dans des tubes horizontaux, lisse ou micro-ailete

    Energy Technology Data Exchange (ETDEWEB)

    Lallemand, M; Branescu, C; Haberschill, P [Centre de Thermique, INSA-CNRS, UMR 5008, Villeurbanne (France)

    2001-07-01

    The purpose of this study is to experimentally investigate forced convective boiling. The heat transfer coefficients of pure refrigerant R22 and non azeotropic refrigerant mixture R407C were measured in both a smooth tube and a microfin tube. The tests have been carried out with a uniform heat flux all along the tube length. The refrigerant mass flux was varied from 100 to 300 kg m{sup -2} s{sup -1} and heat fluxes from 10 to 30 kW m{sup -2}. Local heat transfer coefficient depend strongly on heat flux at a low quality and on mass fluxes at a high quality. When compared to smooth tube, the microfin tubes exhibit a significant heat transfer enhancement, up to 180%. In comparison to R22, the R407C heat transfer coefficients of smooth and microfin tubes are 15 to 35% lower, respectively. The best heat transfer enhancement is obtained at low heat flux and mass flow rate. (Author)

  19. Enhancement of heat transfer. The performance of micro-fin tubes

    International Nuclear Information System (INIS)

    Muzzio, A.

    2001-01-01

    Micro-fin tubes are characterised by numerous, very small integral fins that spiral down the inner surface. A very interesting feature of their performance in flow boiling and condensation is a large heat transfer enhancement accompanied by a low pressure drop penalty. This paper presents a general overview of micro-fin tubes and of their performance in evaporation, condensation and single-phase flow [it

  20. Experimental study on void fraction of two-phase flow inside a micro-fin tube

    OpenAIRE

    Koyama, Shigeru; Chen, Yongchang; Kitano, Ryuji; Kuwahara, Ken

    2001-01-01

    In this paper the void fraction and flow pattern of the two-phase flow in a micro-fin tube were investigated experimentally for a pure refrigerant HFC134a. The experiment was carried out at a pressure range of 0.6 and 1.2MPa with mass velocities of 90 and 180kg/m^2 s, in which the vapor quality varied from 0 to 1. The void fraction was measured by means of simultaneously closing valves of both sides of the test tube at adiabatic condition. Experimental results for the micro-fin tube were comp...

  1. Experimental research on single phase convection heat transfer in micro-fin tube

    International Nuclear Information System (INIS)

    Fan Guangming; Sun Zhongning; Zhu Sheng

    2011-01-01

    An experimental investigation of heat transfer and flow resistance characteristics of single phase water in three micro-fin tubes with different fin height was conducted. At the same time, the efficiency of micro-fin tubes within the experimental scope was evaluated and the optimal working region was determined. Based on the experimental data in the optimal working region, correlations for predicting the heat transfer and flow resistance were also given by multiple regression method. The result indicates that the micro-fin tubes can greatly enhance the single-phase heat transfer in turbulent flow, and the increase of heat transfer coefficient is higher than the increase of flow resistance. The accuracy of the correlation is very high, of which the deviation from the experimental value is very small. (authors)

  2. Flow condensation heat transfer coefficients of R22, R134a, R407C, and R410A inside plain and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Dongsoo; Cho, Youngmok; Park, Kiho [Inha Univ., Incheon (Korea). Dept. of Mechanical Engineering

    2004-01-01

    Flow condensation heat transfer coefficients (HTCs) of R22, R134a, R407C, and R410A inside horizontal plain and microfin tubes of 9.52 mm outside diameter and 1 m length were measured at the condensation temperature of 40{sup o}C with mass fluxes of 100, 200, and 300 kg m{sup -2} s{sup -1} and a heat flux of 7.7-7.9 kW m{sup -2}. For a plain tube, HTCs of R134a and R410A were similar to those of R22 while HTCs of R407C are 11-15% lower than those of R22. For a microfin tube, HTCs of R134a were similar to those of R22 while HTCs of R407C and R410A were 23-53% and 10-21% lower than those of R22. For a plain tube, our correlation agreed well with the present data for all refrigerants exhibiting a mean deviation of 11.6%. Finally, HTCs of a microfin tube were 2-3 times higher than those of a plain tube and the heat transfer enhancement factor decreased as the mass flux increased for all refrigerants tested. (Author)

  3. Post-Dryout Heat Transfer to a Refrigerant Flowing in Horizontal Evaporator Tubes

    Science.gov (United States)

    Mori, Hideo; Yoshida, Suguru; Kakimoto, Yasushi; Ohishi, Katsumi; Fukuda, Kenichi

    Studies of the post-dryout heat transfer were made based on the experimental data for HFC-134a flowing in horizontal smooth and spiral1y grooved (micro-fin) tubes and the characteristics of the post-dryout heat transfer were c1arified. The heat transfer coefficient at medium and high mass flow rates in the smooth tube was lower than the single-phase heat transfer coefficient of the superheated vapor flow, of which mass flow rate was given on the assumption that the flow was in a thermodynamic equilibrium. A prediction method of post-dryout heat transfer coefficient was developed to reproduce the measurement satisfactorily for the smooth tube. The post dryout heat transfer in the micro-fin tube can be regarded approximately as a superheated vapor single-phase heat transfer.

  4. Convective boiling performance of refrigerant R-134a in herringbone and microfin copper tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bandarra Filho, Enio P [Faculdade de Engenharia Mecanica, Universidade Federal de Uberlandia, Av. Joao Naves de Avila, 2160 Bloco 1M, Santa Monica, Uberlandia, MG (Brazil); Saiz Jabardo, Jose M [Escuela Politecnica Superior, Universidad de la Coruna, Calle Mendizabal s/n, 15403 Ferrol, Espana (Spain)

    2006-01-01

    This paper reports an experimental investigation of convective boiling heat transfer and pressure drop of refrigerant R-134a in smooth, standard microfin and herringbone copper tubes of 9.52mm external diameter. Tests have been conducted under the following conditions: inlet saturation temperature of 5{sup o}C, qualities from 5 to 90%, mass velocity from 100 to 500kgs{sup -1}m{sup -2}, and a heat flux of 5kWm{sup -2}. Experimental results indicate that the herringbone tube has a distinct heat transfer performance over the mass velocity range considered in the present study. Thermal performance of the herringbone tube has been found better than that of the standard microfin in the high range of mass velocities, and worst for the smallest mass velocity (G=100kgs{sup -1}m{sup -2}) at qualities higher than 50%. The herringbone tube pressure drop is higher than that of the standard microfin tube over the whole range of mass velocities and qualities. The enhancement parameter is higher than one for both tubes for mass velocities lower than 200kgs{sup -1}m{sup -2}. Values lower than one have been obtained for both tubes in the mass velocity upper range as a result of a significant pressure drop increment not followed by a correspondent increment in the heat transfer coefficient. (author)

  5. Experimental study on condensation heat transfer enhancement and pressure drop penalty factors in four microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Han, D [Korea University, Seoul (Korea). Institute of Advanced Machinery Design; Lee, Kyu-Jung [Korea University, Seoul (Korea). Dept. of Mechanical Engineering

    2005-08-01

    Heat transfer and pressure drop characteristics of four microfin tubes were experimentally investigated for condensation of refrigerants R134a, R22, and R410A in four different test sections. The microfin tubes examined during this study consisted of 8.92, 6.46, 5.1, and 4 mm maximum inside diameter. The effect of mass flux, vapor quality, and refrigerants on condensation was investigated in terms of the heat transfer enhancement factor and the pressure drop penalty factor. The pressure drop penalty factor and the heat transfer enhancement factor showed a similar tendency for each tube at given vapor quality and mass flux. Based on the experimental data and the heat-momentum analogy, correlations for the condensation heat transfer coefficients in an annular flow regime and the frictional pressure drops are proposed. (author)

  6. Flow boiling heat transfer of carbon dioxide inside a small-sized microfin tube

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Chaobin; Haraguchi, Nobori; Hihara, Eiji [Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa-shi, Chiba 277-8563 (Japan)

    2010-06-15

    This study investigated the flow boiling heat transfer of carbon dioxide inside a small-sized microfin tube (mean inner diameter: 2.0 mm; helix angle: 6.3 ) at a saturation temperature of 15 C, and heat and mass flux ranges of 4.5-18 kW m{sup -2} and 360-720 kg m{sup -2} s{sup -1}, respectively. Although, experimental results indicated that heat flux has a significant effect on the heat transfer coefficient, the coefficient does not always increase with mass flux, as in the case of conventional refrigerants such as HFCs or HCFCs. Under certain conditions, the heat transfer coefficient at a high mass flux was lower than that at a lower mass flux, indicating that convective heat transfer had a suppression effect on nucleate boiling. The heat transfer coefficients in the microfin tubes were 1.9{proportional_to}2.3 times the values in smooth tubes of the same diameter under the same experimental conditions, and the dryout quality was much higher, ranging from 0.9 to 0.95. The experimental results indicated that using microfin tubes may considerably increase the overall heat transfer performance. (author)

  7. Prediction method for flow boiling heat transfer in a herringbone microfin tube

    Energy Technology Data Exchange (ETDEWEB)

    Wellsandt, S; Vamling, L [Chalmers University of Technology, Gothenburg (Sweden). Department of Chemical Engineering and Environmental Science, Heat and Power Technology

    2005-09-01

    Based on experimental data for R134a, the present work deals with the development of a prediction method for heat transfer in herringbone microfin tubes. As is shown in earlier works, heat transfer coefficients for the investigated herringbone microfin tube tend to peak at lower vapour qualities than in helical microfin tubes. Correlations developed for other tube types fail to describe this behaviour. A hypothesis that the position of the peak is related to the point where the average film thickness becomes smaller than the fin height is tested and found to be consistent with observed behaviour. The proposed method accounts for this hypothesis and incorporates the well-known Steiner and Taborek correlation for the calculation of flow boiling heat transfer coefficients. The correlation is modified by introducing a surface enhancement factor and adjusting the two-phase multiplier. Experimental data for R134a are predicted with an average residual of 1.5% and a standard deviation of 21%. Tested against experimental data for mixtures R410A and R407C, the proposed method overpredicts experimental data by around 60%. An alternative adjustment of the two-phase multiplier, in order to better predict mixture data, is discussed. (author)

  8. Experimental analysis of refrigerants flow boiling inside small sized microfin tubes

    Science.gov (United States)

    Diani, Andrea; Rossetto, Luisa

    2017-07-01

    The refrigerant charge reduction is one of the most challenging issues that the scientific community has to cope to reduce the anthropic global warming. Recently, mini microfin tubes have been matter of research, since they can reach better thermal performance in small domains, leading to a further refrigerant charge reduction. This paper presents experimental results about R134a flow boiling inside a microfin tube having an internal diameter at the fin tip of 2.4 mm. The mass flux was varied between 375 and 940 kg m-2 s-1, heat flux from 10 to 50 kW m-2, vapor quality from 0.10 to 0.99. The saturation temperature at the inlet of the test section was kept constant and equal to 30 °C. R134a thermal and fluid dynamic performances are presented and compared against those obtained with R1234ze(E) and R1234yf and against values obtained during R134a flow boiling inside a 3.4 mm ID microfin tube.

  9. Evaporating heat transfer characteristics of R22 and R410A in 9.52 mm O.D. smooth and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M H; Shin, J S; Lim, B H [Sam Sung Electronics Corporation Limited (Korea, Republic of)

    1998-10-01

    An experimental investigation of evaporating heat transfer in 9.52 mm horizontal copper tubes was conducted. The refrigerant tested were R22 and near-azeotropic mixture, R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was heated by the heat transfer fluid(hot water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained and refrigerant quality varied from 0.2 to 0.8. The results were reported for evaporation at 15 deg. C in a 0.92 m long test section for 30{approx}60 kg/h mass flow rate. The local and average heat transfer coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average evaporation heat transfer coefficients of R22 and R410A for the microfin tubes were 86{approx}227% and 64{approx}199%, respectively, higher than those for the smooth tube. When compared to R22 at the same test conditions, the evaporating heat transfer coefficients for R410A were 97{approx}129% of R22. (author). 23 refs., 9 figs., 4 tabs.

  10. Condensing heat transfer characteristics of R22 and R410A in 9.52 mm O.D. smooth and microfin tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M H; Shin, J S; Lim, B H [Sam Sung Electronics Corporation Limited (Korea, Republic of)

    1998-10-01

    An experimental investigation of condensation heat transfer in 9.52 mm horizontal copper tubes was conducted using R22 and R410A. The test rig had a straight, horizontal test section with an active length of 0.92 m and was cooled by the heat transfer fluid(cold water) circulated in a surrounding annulus. Constant heat flux of 11.0 kW/m{sup 2} was maintained throughout the experiment and refrigerant quality varied from 0.9 to 0.1. The condensation test results at 45 deg. C were reported for 40{approx}80 kg/h mass flow rate. The local and average condensation coefficients for seven microfin tubes were presented compared to those for a smooth tube. The average condensation coefficients of R22 and R410A for the microfin tubes were 1.7{approx}3.19 and 1.7{approx}2.94 times larger than those in smooth tube, respectively. (author). 19 refs., 9 figs., 4 tabs.

  11. Condensation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low mass fluxes

    Science.gov (United States)

    Kim, Nae-Hyun

    2016-12-01

    R-410A condensation heat transfer and pressure drop data are provided for a 7.0 mm O.D. microfin tube at low mass fluxes (50-250 kg/m2 s). The heat transfer coefficient of the microfin tube shows a minimum behavior with the mass flux. At a low mass flux, where flow pattern is stratified, condensation induced by surface tension by microfins overwhelms condensation induced by shear, and the heat transfer coefficient decreases as mass flux increases. At a high mass flux, where flow pattern is annular, condensation induced by shear governs the heat transfer, and the heat transfer coefficient increases as mass flux increases. The pressure drop of the microfin tube is larger than that of the smooth tube at the annular flow regime. On the contrary, the pressure drop of the smooth tube is larger than that of the microfin tube at the stratified flow regime.

  12. In-tube flow boiling of R-407C and R-407C/oil mixtures. Part 1: Microfin tube

    Energy Technology Data Exchange (ETDEWEB)

    Zuercher, O; Thome, J R; Favrat, D

    1999-07-01

    In-tube evaporation tests for R-407C and R-407C/oil are reported for a microfin tube. The tests were run at a nominal inlet pressure of 645 kPa (93.5 psia) at mass velocities of 100, 200 and 300 kg/(m{sup 2}{center{underscore}dot}s) (20.5, 41, and 61 lb/s{center{underscore}dot}ft{sup 2}) over nearly the entire vapor quality range. At similar operating conditions, pure R-407C performed similarly to previous pure R-134a tests at the highest mass velocity, but lower than R-134a for the other mass velocities. Any amount of oil tended to decrease local R-407C microfin heat transfer coefficients, especially at high vapor qualities were degradations of as much as 50% or more occurred. Two-phase pressure drops were increased by the presence of oil, especially at high vapor qualities. Buildup of the local oil mass fraction in the microfin test sections was observed at high vapor qualities, together with the formation of slowly flowing viscous liquid films, a phenomenon that became more acute at lower mass velocities.

  13. Experiments on condensation heat transfer characteristics inside a microfin tube with R410A

    Energy Technology Data Exchange (ETDEWEB)

    Han, D H; Cho, Y J [Korea University Graduate School, Seoul (Korea); Lee, K J; Park, S S [Korea University, Seoul (Korea)

    2000-11-01

    Due to the ozone depletion and global warming potentials, some refrigerants (CFCs and HCFCs) have been rapidly substituted. R410A is considered as the alternative refrigerant of R22 for the air-conditioners used at home and in industry. Experiments on the condensation heat transfer characteristics inside a smooth or a micro-fin tube with R410A are performed in this study. The test tubes 7/9.52 mm in outer diameters and 3 m in length are used. Varying the mass flux of the refrigerant and the condensation temperatures, the average heat transfer coefficients and pressure drop are investigated. It is shown that the heat transfer is enhanced and the amount of pressure drops are larger in the microfin tube than the smooth tube. From the heat transfer enhancement coefficient and the pressure penalty factor, it is found that the high heat transfer enhancement coefficients are obtained in the range of small mass flux while the penalty factors are almost equal. (author). 13 refs., 12 figs., 1 tab.

  14. R245fa Flow Boiling inside a 4.2 mm ID Microfin Tube

    Science.gov (United States)

    Longo, G. A.; Mancin, S.; Righetti, G.; Zilio, C.

    2017-11-01

    This paper presents the R245fa flow boiling heat transfer and pressure drop measurements inside a mini microfin tube with internal diameter at the fin tip of 4.2 mm, having 40 fins, 0.15 mm high with a helix angle of 18°. The tube was brazed inside a copper plate and electrically heated from the bottom. Sixteen T-type thermocouples are located in the copper plate to monitor the wall temperature. The experimental measurements were carried out at constant mean saturation temperature of 30 °C, by varying the refrigerant mass velocity between 100 kg m-2 s-1 and 300 kg m-2 s-1, the vapour quality from 0.15 to 0.95, at two different heat fluxes: 30 and 60 kW m-2. The experimental results are presented in terms of two-phase heat transfer coefficient, onset dryout vapour quality, and frictional pressure drop. Moreover, the experimental measurements are compared against the most updated models for boiling heat transfer coefficient and frictional pressure drop estimations available in the open literature for microfin tubes.

  15. Experimental studies on the evaporative heat transfer and pressure drop of CO{sub 2} and CO{sub 2}/propane mixtures flowing upward in smooth and micro-fin tubes with outer diameter of 5 mm for an inclination angle of 45

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jin Min; Kim, Min Soo [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744 (Korea); Kim, Yong Jin [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2010-08-15

    Heat transfer characteristics show different tendency according to the tube orientations such as horizontal, vertical, and inclined positions. In this study, evaporative heat transfer characteristics and pressure drop of CO{sub 2} and CO{sub 2}/propane mixtures flowing upward are investigated in inclined smooth and micro-fin tubes. Smooth and micro-fin tubes with outer diameter of 5 mm and length of 1.44 m with inclination angle of 45 were chosen as test tubes. Average inner diameters of test tubes are 4.0 mm (smooth tube) and 4.13 mm (micro-fin tube). The tests were conducted at mass fluxes from 212 to 656 kg/m{sup 2} s, saturation temperatures from -10 to 30 C and heat fluxes from 15 to 60 kW/m{sup 2} for CO{sub 2}. In addition, for CO{sub 2}/propane mixtures, the test was carried out at inlet temperatures from -10 to 30 C for several compositions (75/25, 50/50, 25/75 wt%) with the same mass fluxes, heat fluxes applied for CO{sub 2}. Heat transfer coefficients in inclined tube are approximately 1.8-3 times higher than those in horizontal tube and the average pressure drop of inclined tube exists between that of horizontal and vertical tubes. (author)

  16. Horizontal beam tubes in FRM-II

    International Nuclear Information System (INIS)

    Coors, D.; Vanvor, D.

    2001-01-01

    The new research reactor in Garching FRM-II is equipped with 10 leak tight horizontal beam tubes (BT1 - BT10), each of them consisting of a beam tube structure taking an insert with neutron channels. The design of all beam tube structures is similar whereas the inserts are adapted to the special requirements of the using of each beam tube. Inside the reflector tank the beam tube structures are shaped by the inner cones which are made of Al-alloy with circular and rectangular cross sections. They are located in the region of maximum neutron flux (exception BT10), they are directly connected to the flanges of the reflector tank, their lengths are about 1.5 m (exception BT10) and their axes are directed tagentially to the core centre thus contributing to a low γ-noise at the experiments. (orig.)

  17. Condensation heat transfer for refrigerant-oil mixtures in microfin tube condenser

    Energy Technology Data Exchange (ETDEWEB)

    Cho, K N [Sungkyunkwan University, Seoul (Korea); Tae, S J [Sungkyunkwan University Graduate School, Seoul (Korea)

    2000-04-01

    Condensation heat transfer experiments for R-22 and R-407 C refrigerants mixed with mineral oil and POE oil respectively were performed in straight and U-bend sections of a microfin tube. Experimental parameters were an oil concentration from 0 to 5 %, a mass flux from 100 to 400 kg/m{sup 2}s and an inlet quality from 0.5 to 0.9. The enhancement factors for R-22 and R-407 C refrigerants at the first straight section decreased continuously as the oil concentration increased. They decreased rapidly as the mass maximum at the 90 deg. position. The heat transfer coefficients at the second straight section within the dimensionless length of 48 were larger by a maximum of 33 % than the average heat transfer coefficients at the first straight section. (author). 10 refs., 6 figs., 1 tab.

  18. Evaporation heat transfer characteristics inside the U-bend of the smooth and the microfin tube using alternative refrigerant

    Energy Technology Data Exchange (ETDEWEB)

    Cho, K N [Sung Kyun Kwan University, Seoul (Korea, Republic of); Kim, B G [Sung Kyun Kwan University Graduate School, Seoul (Korea, Republic of)

    1997-09-01

    The present work experimentally investigated the effects of mass flux, heat flux, inlet quality on the heat transfer performance inside the U-bend of smooth and microfin tube using R-22 and R-407C refrigerants. The parameters were 200 and 400 kg/m{sup 2} s for mass flux, 6 and 12 kw/m{sup 2} for heat flux, 0.1 and 0.2 for inlet quality under the pressure of 0.65 MPa. The apparatus consisted of the test section of four straight sections and three U-bends, preheater, condenser, refrigerant pump, mass flow meter etc. The average heat transfer coefficient at the downstream straight section after U-bend was affected by U-bend due to the centrifugal force and mixing of two-phase flow in the U-bend. The average heat transfer coefficient at the U-bend was 4{approx}33 % higher than that at the straight section. The average heat transfer coefficients were affected in the order of mass flux, heat flux and inlet quality. The average heat transfer coefficients in the microfin tube were lager by 19{approx}49 % and 33{approx}69 % than that in the smooth tube at the straight section and at the U-bend separately. The average heat transfer coefficients for R-407C were larger by 33{approx}41 % and 17{approx}29% than that for R-22 in the smooth tube and the microfin tube separately. (author). 24 refs., 9 figs.

  19. Sea water desalination by horizontal tubes evaporator

    International Nuclear Information System (INIS)

    Mohammadi, H.K.; Mohit, M.

    1986-01-01

    Desalinated water supplies are one of the problems of the nuclear power plants located by the seas. This paper explains saline water desalination by a Horizontal Tube Evaporator (HTE) and compares it with flash evaporation. A thermo compressor research project using HTE method has been designed, constructed, and operated at the Esfahan Nuclear Technology Center ENTC. The poject's ultimate goal is to obtain empirical formulae based on data gathered during operation of the unit and its subsequent development towards design and construction of desalination plants on an industrial scale

  20. Enhanced Evaporation and Condensation in Tubes

    Science.gov (United States)

    Honda, Hiroshi

    A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

  1. Sheared bioconvection in a horizontal tube

    Science.gov (United States)

    Croze, O. A.; Ashraf, E. E.; Bees, M. A.

    2010-12-01

    The recent interest in using microorganisms for biofuels is motivation enough to study bioconvection and cell dispersion in tubes subject to imposed flow. To optimize light and nutrient uptake, many microorganisms swim in directions biased by environmental cues (e.g. phototaxis in algae and chemotaxis in bacteria). Such taxes inevitably lead to accumulations of cells, which, as many microorganisms have a density different to the fluid, can induce hydrodynamic instabilites. The large-scale fluid flow and spectacular patterns that arise are termed bioconvection. However, the extent to which bioconvection is affected or suppressed by an imposed fluid flow and how bioconvection influences the mean flow profile and cell transport are open questions. This experimental study is the first to address these issues by quantifying the patterns due to suspensions of the gravitactic and gyrotactic green biflagellate alga Chlamydomonas in horizontal tubes subject to an imposed flow. With no flow, the dependence of the dominant pattern wavelength at pattern onset on cell concentration is established for three different tube diameters. For small imposed flows, the vertical plumes of cells are observed merely to bow in the direction of flow. For sufficiently high flow rates, the plumes progressively fragment into piecewise linear diagonal plumes, unexpectedly inclined at constant angles and translating at fixed speeds. The pattern wavelength generally grows with flow rate, with transitions at critical rates that depend on concentration. Even at high imposed flow rates, bioconvection is not wholly suppressed and perturbs the flow field.

  2. Investigation on the heat transfer characteristics during flow boiling of liquefied natural gas in a vertical micro-fin tube

    Science.gov (United States)

    Xu, Bin; Shi, Yumei; Chen, Dongsheng

    2014-03-01

    This paper presents an experimental investigation on the heat transfer characteristics of liquefied natural gas flow boiling in a vertical micro-fin tube. The effect of heat flux, mass flux and inlet pressure on the flow boiling heat transfer coefficients was analyzed. The Kim, Koyama, and two kinds of Wellsandt correlations with different Ftp coefficients were used to predict the flow boiling heat transfer coefficients. The predicted results showed that the Koyama correlation was the most accurate over the range of experimental conditions.

  3. Effect of refrigeration lubricants on the heat transfer performance in the microfin tube evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Cho, K N; Tae, S J [Sung Kyun Kwan University, Seoul (Korea)

    1999-01-01

    The present study experimentally investigated the defect of refrigeration lubricant on the heat transfer performance in the straight sections and U-bend of a microfin tube evaporator by using R-22/mineral oil and R-407C/POE oil. The apparatus consisted of test section with U-bend, preheater, condenser, oil injection and sampling devices, magnetic pump, mass flow meter etc. The experimental parameters were oil concentration of 0 to 5 wt%, inlet quality of 0.1 to 0.5, mass flux of 219 and 400 kg/m{sup 2}s and heat flux of 10 and 20 kw/m{sup 2}. The effects of parameters on the heat transfer coefficients were large in the order of inlet quality, mass flux and heat flux as oil concentration got increased. As oil concentration was increased, heat transfer coefficients were continuously decreased for R-22 and increased by 3% up to the concentration of 1% and then decreased for R-407C under the condition of large inlet quality, and small mass flux and heat flux. But, the heat transfer coefficients were increased up to the opposite conditions. The variation of enhancement factors for R-407C refrigerants under the opposite conditions. The variation of enhancement factors for R-407C was under 50% of that for R-22 and the variation with respect to the positions in the test section was small. The pressure drops were increased for both R-22 and R-407C refrigerants as oil concentration was increased. The pressure drops for R-407C were smaller by the maximum of 18% than those for R-22. 12 refs., 1 tab., 14 figs.

  4. Evaporation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low flow rates

    International Nuclear Information System (INIS)

    Kim, Hae Hyun

    2015-01-01

    Microfin tubes having an outside diameter (O.D.) of 7.0 mm are widely used in residential air conditioning systems and heat pumps. It is known that the mass fluxes for air conditioners and heat pumps under partial load conditions are several tens of kg/m 2 s. However, literature surveys reveal that previous investigations were limited to mass flux over 100 kg/m 2 s. In this study, we conduct R-410A evaporation heat-transfer tests at low mass fluxes (50-250 kg/m 2 s) using a 7.0 mm O.D. microfin tube. During the test, the saturation temperature was maintained at 8 degrees celsius, and the heat flux was maintained at 4.kW/m"2. For comparison purposes, we also test a smooth tube with a 7.0 mm O.D. The results showed that the heat-transfer enhancement factor of the microfin tube increased as the mass flux decreased up to 150 kg/m 2 s, which decreased as the mass flux further decreased. The reason for this was attributed to the change of the flow pattern from an annular flow to a stratified flow. Within the test range, the frictional pressure drops of the microfin tube were approximately the same as those of the smooth tube. We then compare experimental data obtained with the predictions obtained for the existing correlations

  5. Evaporation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low flow rates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Hyun [Div. of Mechanical System Engineering, Incheon National University, Incheon (Korea, Republic of)

    2015-09-15

    Microfin tubes having an outside diameter (O.D.) of 7.0 mm are widely used in residential air conditioning systems and heat pumps. It is known that the mass fluxes for air conditioners and heat pumps under partial load conditions are several tens of kg/m{sup 2}s. However, literature surveys reveal that previous investigations were limited to mass flux over 100 kg/m{sup 2}s. In this study, we conduct R-410A evaporation heat-transfer tests at low mass fluxes (50-250 kg/m{sup 2}s) using a 7.0 mm O.D. microfin tube. During the test, the saturation temperature was maintained at 8 degrees celsius, and the heat flux was maintained at 4.kW/m{sup 2}. For comparison purposes, we also test a smooth tube with a 7.0 mm O.D. The results showed that the heat-transfer enhancement factor of the microfin tube increased as the mass flux decreased up to 150 kg/m{sup 2}s, which decreased as the mass flux further decreased. The reason for this was attributed to the change of the flow pattern from an annular flow to a stratified flow. Within the test range, the frictional pressure drops of the microfin tube were approximately the same as those of the smooth tube. We then compare experimental data obtained with the predictions obtained for the existing correlations.

  6. Prediction of friction factor of pure water flowing inside vertical smooth and microfin tubes by using artificial neural networks

    Science.gov (United States)

    Çebi, A.; Akdoğan, E.; Celen, A.; Dalkilic, A. S.

    2017-02-01

    An artificial neural network (ANN) model of friction factor in smooth and microfin tubes under heating, cooling and isothermal conditions was developed in this study. Data used in ANN was taken from a vertically positioned heat exchanger experimental setup. Multi-layered feed-forward neural network with backpropagation algorithm, radial basis function networks and hybrid PSO-neural network algorithm were applied to the database. Inputs were the ratio of cross sectional flow area to hydraulic diameter, experimental condition number depending on isothermal, heating, or cooling conditions and mass flow rate while the friction factor was the output of the constructed system. It was observed that such neural network based system could effectively predict the friction factor values of the flows regardless of their tube types. A dependency analysis to determine the strongest parameter that affected the network and database was also performed and tube geometry was found to be the strongest parameter of all as a result of analysis.

  7. R1234yf vs. R134a Flow Boiling Heat Transfer Inside a 3.4 mm ID Microfin Tube

    Science.gov (United States)

    Diani, A.; Mancin, S.; Rossetto, L.

    2014-11-01

    The refrigerant charge minimization as well as the use of eco-friendly fluids can be considered two of the most important targets for these applications to cope with the new environmental challenges. This paper compares the R1234yf and R134a flow boiling heat transfer and pressure drop measurements inside a small microfin tube with internal diameter at the fin tip of 3.4 mm. This study is carried out in an experimental facility built at the Dipartimento di Ingegneria Industriale of the University of Padova especially designed to study both single and two phase heat transfer processes. The microfin tube is brazed inside a copper plate and electrically heated from the bottom. Several T -type thermocouples are inserted in the wall to measure the temperature distribution during the phase change process. In particular, the experimental measurements were carried out at constant saturation temperature of 30 °C, by varying the refrigerant mass velocity between 190 kg m-2 s-1 and 940 kg m-2 s-1, the vapour quality from 0.2 to 0.99, at different imposed heat fluxes. The two refrigerants are compared considering the values of the two-phase heat transfer coefficient and pressure drop.

  8. R1234yf vs. R134a Flow Boiling Heat Transfer Inside a 3.4 mm ID Microfin Tube

    International Nuclear Information System (INIS)

    Diani, A; Mancin, S; Rossetto, L

    2014-01-01

    The refrigerant charge minimization as well as the use of eco-friendly fluids can be considered two of the most important targets for these applications to cope with the new environmental challenges. This paper compares the R1234yf and R134a flow boiling heat transfer and pressure drop measurements inside a small microfin tube with internal diameter at the fin tip of 3.4 mm. This study is carried out in an experimental facility built at the Dipartimento di Ingegneria Industriale of the University of Padova especially designed to study both single and two phase heat transfer processes. The microfin tube is brazed inside a copper plate and electrically heated from the bottom. Several T -type thermocouples are inserted in the wall to measure the temperature distribution during the phase change process. In particular, the experimental measurements were carried out at constant saturation temperature of 30 °C, by varying the refrigerant mass velocity between 190 kg m −2 s −1 and 940 kg m −2 s −1 , the vapour quality from 0.2 to 0.99, at different imposed heat fluxes. The two refrigerants are compared considering the values of the two-phase heat transfer coefficient and pressure drop

  9. R1234yf vs. R134a Flow Boiling Heat Transfer Inside a 3.4 mm ID Microfin Tube

    Energy Technology Data Exchange (ETDEWEB)

    Diani, A; Mancin, S; Rossetto, L [Università di Padova, Dipartimento di Ingegneria Industriale, Via Venezia 1, 35131 – Padova (Italy)

    2014-11-19

    The refrigerant charge minimization as well as the use of eco-friendly fluids can be considered two of the most important targets for these applications to cope with the new environmental challenges. This paper compares the R1234yf and R134a flow boiling heat transfer and pressure drop measurements inside a small microfin tube with internal diameter at the fin tip of 3.4 mm. This study is carried out in an experimental facility built at the Dipartimento di Ingegneria Industriale of the University of Padova especially designed to study both single and two phase heat transfer processes. The microfin tube is brazed inside a copper plate and electrically heated from the bottom. Several T -type thermocouples are inserted in the wall to measure the temperature distribution during the phase change process. In particular, the experimental measurements were carried out at constant saturation temperature of 30 °C, by varying the refrigerant mass velocity between 190 kg m{sup −2} s{sup −1} and 940 kg m{sup −2} s{sup −1}, the vapour quality from 0.2 to 0.99, at different imposed heat fluxes. The two refrigerants are compared considering the values of the two-phase heat transfer coefficient and pressure drop.

  10. Boiling heat transfer on horizontal tube bundles

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Nucleate boiling heat transfer characteristics for a tube in a bundle differ from that for a single tube in a pool and this difference is known as 'tube bundle effect.' There exist two bundle effects, positive and negative. The positive bundle effect enhances heat transfer due to convective flow induced by rising bubbles generated from the lower tubes, while the negative bundle effect deteriorates heat transfer due to vapor blanketing caused by accumulation of bubbles. Staggered tube bundles tested and found that the upper tubes in bundles have higher heat transfer coefficients than the lower tubes. The effects of various parameters such as pressure, tube geometry and oil contamination on heat transfer have been examined. Some workers attempted to clarify the mechanism of occurrence of 'bundle effect' by testing tube arrangements of small scale. All reported only enhancement in heat transfer but results showed the symptom of heat transfer deterioration at higher heat fluxes. As mentioned above, it has not been clarified so far even whether the 'tube bundle effect' should serve as enhancement or deterioration of heat transfer in nucleate boiling. In this study, experiments are performed in detail by using bundles of small scale, and effects of heat flux distribution, pressure and tube location are clarified. Furthermore, some consideration on the mechanisms of occurrence of 'tube bundle effect' is made and a method for prediction of heat transfer rate is proposed

  11. Evaporation heat transfer and pressure drop of R-410A in three 7.0 mm O.D. microfin tubes having different inside geometries

    International Nuclear Information System (INIS)

    Kim, Nae Hyun

    2015-01-01

    R-410A evaporation heat transfer and pressure drop data are provided for three 7.0 mm O.D. microfin tubes. The microfin tubes had different helix angle, fin height and fin apex angle. Tests were conducted for a range of quality (0.2 ∼ 0.8), mass flux (216 ∼ 390 kg/m 2 s), heat flux (9 ∼ 17 kW/m 2 ) and saturation temperature (8 ∼ 12 .deg. C). It was found that three microfin tubes yielded approximately the same heat transfer coefficients. Microfin tube with larger inter-fin spacing or smaller helix angle yielded lager pressure drop. Both heat transfer coefficient and pressure drop increased as mass flux or quality increased. However, they decreased as saturation temperature increased. The range of heat transfer enhancement factor (1.37 ∼ 1.97) was comparable with that of pressure drop penalty factor (1.22 ∼ 1.77). Data are compared with available heat transfer and pressure drop correlations

  12. Composite Coiled Tubing for Extended Reach in Horizontal Oil Wells

    DEFF Research Database (Denmark)

    Costache, Andrei; Berggreen, Christian

    2017-01-01

    Conventional steel coiled tubing cannot reach along the entire length of very long horizontal oil wells. A lighter and more buoyant coiled tube is made possible using composite materials. The high stiffness to weight ratio of fiber reinforced polymers, coupled with a lower coefficient of friction......, has the potential of greatly extending the reach in horizontal oil wells. This study shows how to design composite coiled tubing and gives a comprehensive discussion about the most influential parameters. Several solutions, using glass-fiber and carbon are considered. Finite element models are used...

  13. Falling film flow, heat transfer and breakdown on horizontal tubes

    International Nuclear Information System (INIS)

    Rogers, J.T.

    1980-11-01

    Knowledge of falling film flow and heat transfer characteristics on horizontal tubes is required in the assessment of certain CANDU reactor accident sequences for those CANDU reactors which use moderator dump as one of the shut-down mechanisms. In these reactors, subsequent cooling of the calandria tubes is provided by falling films produced by sprays. This report describes studies of falling film flow and heat transfer characteristics on horizontal tubes. Analyses using integral methods are given for laminar and turbulent flow, ignoring and accounting for momentum effects in the film. Preliminary experiments on film flow stability on horizontal tubes are described and various mechanisms of film breakdown are examined. The work described in this report shows that in LOCA with indefinitely delayed ECI in the NPD or Douglas Point (at 70 percent power) reactors, the falling films on the calandria tubes will not be disrupted by any of the mechanisms considered, provided that the pressure tubes do not sag onto the calandria tubes. However, should the pressure tubes sag onto the calandria tubes, film disruption will probably occur

  14. Condensation Analysis of Steam/Air Mixtures in Horizontal Tubes

    International Nuclear Information System (INIS)

    Lee, Kwon Yeong; Bae, Sung Won; Kim, Moo Hwan

    2008-01-01

    Perhaps the most common flow configuration in which a convective condensation occurs is a flow in a horizontal circular tube. This configuration is encountered in air-conditioning and refrigeration condensers as well as condensers in Rankine power cycles. Although a convective condensation is also sometimes contrived to occur in a co-current vertical downward flow, a horizontal flow is often preferred because the flow can be repeatedly passed through the heat exchanger core in a serpentine fashion without trapping liquid or vapor in the return bends. Many researchers have investigated a in-tube condensation for horizontal heat exchangers. However, almost all of them obtained tube section-averaged data without a noncondensable gas. Recently, Wu and Vierow have experimentally studied the condensation of steam in a horizontal heat exchanger with air present. In order to measure the condenser tube inner surface temperatures and to calculate the local heat fluxes, they developed an innovative thermocouple design that allowed for nonintrusive measurements. Here we developed a theoretical model using the heat and mass analogy to analyze a steam condensation with a noncondensable gas in horizontal tubes

  15. Nucleate boiling heat transfer on horizontal tubes in bundles

    International Nuclear Information System (INIS)

    Fujital, Y.; Ohta, H.; Hidaka, S.; Nishikawa, K.

    1986-01-01

    In order to clarify the heat transfer mechanisms of the flooded type horizontal tube bundle evaporator, heat transfer characteristics of tube bundles of experimental scale which consist both of smooth and enhanced tubes were investigated in detail. The experiments of saturated nucleate boiling were performed by using Freon 113 under pressures 0.1 to 1 MPa, and the effects of various parameters, for example, bundle arrangement, heat flux, pressure on the characteristics of an individual tube are clarified. Experimental data is reproduced well by a proposed heat transfer model in which convective heat transfer coefficients due to rising bubbles are estimated as a function of their volumetric flow rate

  16. Flow boiling heat transfer of R134a and R404A in a microfin tube at low mass fluxes and low heat fluxes

    Science.gov (United States)

    Spindler, Klaus; Müller-Steinhagen, Hans

    2009-05-01

    An experimental investigation of flow boiling heat transfer in a commercially available microfin tube with 9.52 mm outer diameter has been carried out. The microfin tube is made of copper with a total fin number of 55 and a helix angle of 15°. The fin height is 0.24 mm and the inner tube diameter at fin root is 8.95 mm. The test tube is 1 m long and is electrically heated. The experiments have been performed at saturation temperatures between 0 and -20°C. The mass flux was varied between 25 and 150 kg/m2s, the heat flux from 15,000 W/m2 down to 1,000 W/m2. All measurements have been performed at constant inlet vapour quality ranging from 0.1 to 0.7. The measured heat transfer coefficients range from 1,300 to 15,700 W/m2K for R134a and from 912 to 11,451 W/m2K for R404A. The mean heat transfer coefficient of R134a is in average 1.5 times higher than for R404A. The mean heat transfer coefficient has been compared with the correlations by Koyama et al. and by Kandlikar. The deviations are within ±30% and ±15%, respectively. The influence of the mass flux on the heat transfer is most significant between 25 and 62.5 kg/m2s, where the flow pattern changes from stratified wavy flow to almost annular flow. This flow pattern transition is shifted to lower mass fluxes for the microfin tube compared to the smooth tube.

  17. An experimental investigation of the effects of spiral angle on the evaporation heat transfer coefficients in microfin tubes with visualization technique

    Science.gov (United States)

    Oh, Se-Yoon

    A smooth tube and five microfin tubes were tested, and evaporation heat transfer coefficients were measured and compared for mass fluxes, 50, 100 and 200 kg/m2 s, and heat fluxes, 5, 10 and 20 kW/m 2, with Refrigerant 134a as a working fluid. The evaporation heat transfer coefficients at quality 0.5 were compared among the smooth and five microfin tubes with spiral angles 6, 12, 18, 25 and 44 degrees. The effect of the spiral angle on the heat transfer coefficients was examined. It was found that the optimal spiral angle where the maximum heat transfer coefficient occurs, mainly depends on mass flux. The optimal spiral angle was 18 degrees for G=50 kg/m2 s, and 6 degrees for G=100 and 200 kg/m 2 s. A borescope was used to visualize the flow on the inside wall of test tubes. The purpose was to find out the effect of the grooves on the liquid flow in microfin tubes and to explain the mechanism of heat transfer enhancement. Temperatures on the tube wall were measured at the same axial location as the imaging sensor of the borescope, and were related to the behavior of the liquid flow on the inside wall of the tubes. The liquid flow in the grooves on the wall was found to be the most important factor in enhancing heat transfer coefficients. The liquid flowed upward along the grooves and covered the upper inside wall of the microfin tubes at G=50 kg/m2 s. When heat flux increases, the liquid flow was found at a higher position. Both liquid viscosity and surface tension decrease, when temperature increases. Thus, the lower viscosity at higher heat flux facilitated the upward motion of the liquid flow in the grooves, so that the momentum force as well as the capillary effect was found to push the liquid along the grooves.* *A CD is included with dissertation containing video clips in avi format which can be viewed with media player.

  18. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoyan, Zhang [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China)], E-mail: gqzxy@sohu.com; Xingqun, Zhang; Yunguang, Chen; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-06-15

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes.

  19. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoyan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); Zhang, Xingqun; Chen, Yunguang; Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-06-15

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5{sup o}C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes. (author)

  20. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    International Nuclear Information System (INIS)

    Zhang Xiaoyan; Zhang Xingqun; Chen Yunguang; Yuan Xiuling

    2008-01-01

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m -2 s -1 , heat flux from 11 to 32 kW m -2 , evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes

  1. A review on critical heat flux in horizontal tubes

    International Nuclear Information System (INIS)

    Baburajan, P.K.; Gaikwad, Avinash; Prabhu, S.V.

    2015-01-01

    Coolant channels of PHWR during accident similar to loss of coolant accident (LOCA) may experience different flow transients with low pressure and low flow conditions. In the advanced PHWRs it is desired to have small amount of positive quality at the exit of the coolant channel to increase the thermal efficiency. Investigation on pressure drop and heat transfer coefficient under subcooled boiling condition is important in the design and operation of the PHWRs. Understanding of thermal hydraulic phenomena associated with horizontal flow is also important in the safety and accident management in these reactors. A detailed experimental investigation on the important thermal hydraulic phenomena of horizontal tubes under low pressure and low flow conditions is carried out. The phenomena covered in this work are measurement of diabatic single phase and subcooled boiling pressure drop and local heat transfer coefficients, steady state CHF, effect of upstream flow restrictions on flow transients and CHF, CHF under oscillatory flow and flow decreasing transients. A detailed literature review is carried out on CHF in horizontal channels to take stock of the works being carried out along with current state of the art and to justify the motivation for the experimental study. This paper presents the review of available literature on horizontal CHF with the results of the experimental work. (author)

  2. Maximum allowable heat flux for a submerged horizontal tube bundle

    International Nuclear Information System (INIS)

    McEligot, D.M.

    1995-01-01

    For application to industrial heating of large pools by immersed heat exchangers, the socalled maximum allowable (or open-quotes criticalclose quotes) heat flux is studied for unconfined tube bundles aligned horizontally in a pool without forced flow. In general, we are considering boiling after the pool reaches its saturation temperature rather than sub-cooled pool boiling which should occur during early stages of transient operation. A combination of literature review and simple approximate analysis has been used. To date our main conclusion is that estimates of q inch chf are highly uncertain for this configuration

  3. Condensation heat transfer of steam on a single horizontal tube

    Science.gov (United States)

    Graber, K. A.

    1983-06-01

    An experimental apparatus was designed, constructed and instrumented in an effort to systematically and carefully study the condensation heat-transfer coefficient on a single, horizontal tube. A smooth, thick-walled copper tube of length 133.5 mm, with an outside diameter of 15.9 mm and an inside diameter of 12.7 mm was instrumented with six wall thermocouples. The temperature rise across the test section was measured accurately using quartz crystal thermometers. The inside heat-transfer coefficient was determined using the Sieder-Tate correlation with leading coefficient of 0.029. Initial steam side data were taken at atmospheric pressure to test the data acquisition/reduction computer programs.

  4. Comparative assessment of condensation models for horizontal tubes

    International Nuclear Information System (INIS)

    Schaffrath, A.; Kruessenberg, A.K.; Lischke, W.; Gocht, U.; Fjodorow, A.

    1999-01-01

    The condensation in horizontal tubes plays an important role e.g. for the determination of the operation mode of horizontal steam generators of VVER reactors or passive safety systems for the next generation of nuclear power plants. Two different approaches (HOTKON and KONWAR) for modeling this process have been undertaken by Forschungszentrum Juelich (FZJ) and University for Applied Sciences Zittau/Goerlitz (HTWS) and implemented into the 1D-thermohydraulic code ATHLET, which is developed by the Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH for the analysis of anticipated and abnormal transients in light water reactors. Although the improvements of the condensation models are developed for different applications (VVER steam generators - emergency condenser of the SWR1000) with strongly different operation conditions (e.g. the temperature difference over the tube wall in HORUS is up to 30 K and in NOKO up to 250 K, the heat flux density in HORUS is up to 40 kW/m 2 and in NOKO up to 1 GW/m 2 ) both models are now compared and assessed by Forschungszentrum Rossendorf FZR e.V. Therefore, post test calculations of selected HORUS experiments were performed with ATHLET/KONWAR and compared to existing ATHLET and ATHLET/HOTKON calculations of HTWS. It can be seen that the calculations with the extension KONWAR as well as HOTKON improve significantly the agreement between computational and experimental data. (orig.) [de

  5. Condensate subcooling near tube exit during horizontal in-tube condensation

    International Nuclear Information System (INIS)

    Hashizume, K.; Abe, N.; Ozeki, T.

    1992-01-01

    In-tube condensation is encountered in various applications for heat exchangers, such as domestic air-conditioning equipment, industrial air-cooled condensers, and moisture separator reheaters (MSRs) for nuclear power pants. Numerous research work has been conducted to predict the condensation heat transfer coefficient, and we have now enough information for thermal design of heat exchangers with horizontal in-tube condensation. Most of the research is analytical and/or experimental work in the annular or stratified flow regime, or experimental work on bulk condensation, i.e., from saturated vapor to complete condensation. On the other hand, there exist few data about the heat transfer phenomena in the very lower-quality region near the tube exit. The purpose of this paper is to clarify the condensation heat transfer phenomena near the tube exit experimentally and analytically, and to predict the degree of condensate subcooling

  6. Heat transfer during forced convection condensation inside horizontal tube

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, T.N. [M.M.M. Engineering College, Gorakhpur, Uttar Pradesh (India). Dept. of Mechanical Engineering; Varma, H.K.; Gupta, C.P. [Roorkee Univ., Uttar Pradesh (India). Dept. of Mechanical and Industrial Engineering

    1995-03-01

    This paper presents the results of an experimental investigation on heat transfer behaviour during forced convection condensation inside a horizontal tube for wavy, semi-annular and annular flows. A qualitative study was made of the effect of various parameters - refrigerant mass flux, vapour quality, condensate film temperature drop and average vapour mass velocity - on average condensing-heat transfer coefficient. Akers-Rosson correlations have been found to predict the heat transfer coefficients within {+-} 25% for the entire range of data. A closer examination of the data revealed that the nature of the relation for the heat transfer coefficient changes from annular and semi-annular flow to wavy flow. Akers-Rosson correlations with changed constant and power have been recommended for the two flow regimes. (author)

  7. Experimental investigation and correlation of two-phase frictional pressure drop of R410A-oil mixture flow boiling in a 5 mm microfin tube

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Guoliang; Hu, Haitao; Huang, Xiangchao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China); Gao, Yifeng [International Copper Association, Shanghai Office, Shanghai 200020 (China)

    2009-01-15

    This study presents experimental two-phase frictional data for R410A-oil mixture flow boiling in an internal spiral grooved microfin tube with outside diameter of 5 mm. Experimental parameters include the evaporation temperature of 5 C, the mass flux from 200 to 400 kg m{sup -2} s{sup -1}, the heat flux from 7.46 to 14.92 kW m{sup -2}, the inlet vapor quality from 0.1 to 0.8, and nominal oil concentration from 0 to 5%. The test results show that the frictional pressure drop of R410A initially increases with vapor quality and then decreases, presenting a local maximum in the vapor quality range between 0.7 and 0.8; the frictional pressure drop of R410A-oil mixture increases with the mass flux, the presence of oil enhances two-phase frictional pressure drop, and the effect of oil on frictional pressure drop is more evident at higher vapor qualities where the local oil concentrations are higher. The enhanced factor is always larger than unity and increases with nominal oil concentration at a given vapor quality. The range of the enhanced factor is about 1.0-2.2 at present test conditions. A new correlation to predict the local frictional pressure drop of R410A-oil mixture flow boiling inside the internal spiral grooved microfin tube is developed based on local properties of refrigerant-oil mixture, and the measured local frictional pressure drop is well correlated with the empirical equation proposed by the authors. (author)

  8. Calculation of vapour bubble growth on the lower generatrix of horizontal tubes

    International Nuclear Information System (INIS)

    Chajka, V.D.

    1987-01-01

    The known models of vapour bubble growth are compared with experimental data. Cinematographic study of vapour formation during water boiling was carried out with elements of horizontal tubes of copper 10, 16, 24, 34 and 70 mm in diameter under the pressure of 100 kPa and specific thermal loadings of 20 and 40 kW/m 2 . According to the experimental data the main volume of vapour phase is occupied by vapour bubbles from the lower part of the horizontal tube. Five stages of vapour bubble growth on the lower generatrix of the horizontal tube: nucleation, growth to the point of breaking off from nucleate centre, the breaking off from the nucleate centre, the tube surface flowing around during floating up, the breaking off from the tube surface, were singled out. The shape of vapour volume varied during the whole period of the bubble growth and it was mainly determined by the horizontal tube diameter. The change of vapour bubble radius in time is the function of the horizontal tube diameter. Comparison of the experimental data with the known models of vapour bubble growth has shown, that every stage of vapour bubble growth on the lower generatrix of the tube is determined by the complex of thermal and hydrodynamic conditions, the effect of which depends on the horizontal tube diameter

  9. A new accelerator tube and column for a horizontal 8 MV tandem

    International Nuclear Information System (INIS)

    Sundquist, M.L.; Rathmell, R.D.; Raatz, J.E.

    1990-01-01

    A horizontal 8 MV tandem is being installed in an existing tank at Kyoto University in Japan. This NEC Model 8UDH is the largest horizontal Pelletron constructed to date. The terminal is charged by two Pelletron chains. The acceleration tube is a metal and ceramic construction made into tube sections with a length of 30 cm each. This tube design adds 27% more live ceramic than in the standard NEC tube design, which had heated apertures in 5 cm long shorted regions every 20 cm. The column structure and tube design are reviewed. (orig.)

  10. Evaporation heat transfer for R-22 and R-407C refrigerant-oil mixture in a microfin tube with a U-bend

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Keumnam; Tae, Sang-Jin [Sungkyunkwan University, Suwon (D.P.R. of Korea). School of Mechanical Engineering

    2000-05-01

    Evaporation heat transfer experiments for two refrigerants, R-407C and R-22, mixed with polyol ester and mineral oils were performed in straight and U-bend sections of a microfin tube. Experimental parameters include an oil concentration varied from 0 to 5%, an inlet quality varied from 0.1 to 0.5, two mass fluxes of 219 and 400 kg m{sup -2} s{sup -1} and two heat fluxes of 10 and 20 kW m{sup -2}. Pressure drop in the test section increased by approximately 20% as the oil concentration increased from 0 to 5%. Enhancement factors decreased as oil concentration increased under inlet quality of 0.5, mass flux of 219 kg m{sup -2} s{sup -1} and heat flux of 10 kW m{sup -2}, whereas they increased under inlet quality of 0.1, mass flux of 400 kg m{sup -2} s{sup -1}, and heat flux of 20 kW m{sup -2}. The local heat transfer coefficient at the outside curvature of a U-bend was larger than that at the inside curvature of a U-bend, and the maximum value occurred at the 90{sup o} position of the U-bend. The heat transfer coefficient was larger in a region of 30 tube diameter length at the second straight section than that at the first straight section. (author)

  11. International diversification and Microfinance

    NARCIS (Netherlands)

    Galema, R.; Lensink, B.W.; Spierdijk, L.

    2011-01-01

    International commercial banks, institutional investors, and private investors have become increasingly interested in financing microfinance institutions (MFIs). This paper investigates whether adding microfinance funds to a portfolio of risky international assets yields diversification gains. By

  12. International diversification and Microfinance

    NARCIS (Netherlands)

    Galema, Rients; Lensink, Robert; Spierdijk, Laura

    International commercial banks, institutional investors, and private investors have become increasingly interested in financing microfinance institutions (MFIs). This paper investigates whether adding microfinance funds to a portfolio of risky international assets yields diversification gains. By

  13. Heat transfer in a membrane assisted fluidised bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.; Volkers, S.; van Sint Annaland, M.; Kuipers, J.A.M.

    2004-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidised bed was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged in a staggered formation with the membrane

  14. Heat transfer in a membrane assisted fluidized bed with immersed horizontal tubes

    NARCIS (Netherlands)

    Deshmukh, S.A.R.K.; Volkers, Sander; van Sint Annaland, M.; Kuipers, J.A.M.

    2005-01-01

    The effect of gas permeation through horizontally immersed membrane tubes on the heat transfer characteristics in a membrane assisted fluidized bed operated in the bubbling fluidization regime was investigated experimentally. Local time-averaged heat transfer coefficients from copper tubes arranged

  15. Flooding in a loop with a vertical and a horizontal tube connected by an elbow

    International Nuclear Information System (INIS)

    Yan Changqi

    1994-01-01

    The experimental research of flooding and flow-reverse in a test loop which a vertical and a horizontal tube connected by an elbow is introduced. According to the experimental results, the effects of the elbow on flooding and flow-reverse is analyzed. The experimental results is compared with the results obtained in vertical tubes. The effect of horizontal tube length and hysteresis in de-flooding are analyzed. Dimensionless parameters was used in data process. The correlations for predicting the flooding point, de-flooding point, completed carry up and flow reverse points are given

  16. Burnout in the horizontal tubes of a furnace waterwall panel

    Energy Technology Data Exchange (ETDEWEB)

    B.Y. Kamenetskii [All-Russia Research Institute of Nuclear Power Engineering (OAO VNIIAM), Moscow (Russian Federation)

    2009-07-01

    An experimental study of heat transfer that occurs in tubes nonuniformly heated over the perimeter at low velocities of subcooled water flowing in them is presented. Experiments with unsteady supply of heat made it possible to determine heat fluxes under burnout conditions. Unusually low values of critical heat fluxes were obtained under such conditions.

  17. Burnout in the horizontal tubes of a furnace waterwall panel

    Science.gov (United States)

    Kamenetskii, B. Ya.

    2009-08-01

    An experimental study of heat transfer that occurs in tubes nonuniformly heated over the perimeter at low velocities of subcooled water flowing in them is presented. Experiments with unsteady supply of heat made it possible to determine heat fluxes under burnout conditions. Unusually low values of critical heat fluxes were obtained under such conditions.

  18. Thermal design of horizontal tube boilers: numerical and experimental investigation

    International Nuclear Information System (INIS)

    Roser, Robert

    1999-01-01

    This work concerns the thermal design of kettle re-boilers. Current methods are highly inaccurate, regarded to the correlations for external heat transfer coefficient at one tube scale, as well as to two-phase flow modelling at boiler scale. The aim of this work is to improve these thermal design methods. It contains an experimental investigation with typical operating conditions of such equipment: an hydrocarbon (n-pentane) with low mass flux. This investigation has lead to characterize the local flow pattern through void fraction measurements and, from this, to develop correlations for void fraction, pressure drop and heat transfer coefficient. The approach is original, since the developed correlations are based on the liquid velocity at minimum cross section area between tubes, as variable characterizing the hydrodynamic effects on pressure drop and heat transfer coefficient. These correlations are shown to give much better results than those suggested up to now in the literature, which are empirical transpositions from methods developed for inside tube flows. Furthermore, the numerical code MC3D has been applied using the correlations developed in this work, leading to a modelization of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author) [fr

  19. Research for rolling effects on flow pattern of gas-water flow in horizontal tubes

    International Nuclear Information System (INIS)

    Luan Feng; Yan Changqi

    2007-01-01

    The flow pattern transition of two-phase flow is caused by the inertial force resulted from rolling and incline of horizontal tubes under rolling state. an experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state, which rolling period is 15 second and rolling angle is 10 degrees, and a pattern flow picture is shown. It was found that there are two flow patterns in one rolling period under some gas flux and water flux. (authors)

  20. Theoretical modeling of steam condensation in the presence of a noncondensable gas in horizontal tubes

    International Nuclear Information System (INIS)

    Lee, Kwon-Yeong; Kim, Moo Hwan; Kim, Moo Hwan

    2008-01-01

    A theoretical model was developed to investigate a steam condensation with a noncondensable gas in a horizontal tube. The heat transfer through the vapor/noncondensable gas mixture boundary layer consists of the sensible heat transfer and the latent heat transfer given up by the condensing vapor, and it must equal that from the condensate film to the tube wall. Therefore, the total heat transfer coefficient is given by the film, condensation and sensible heat transfer coefficients. The film heat transfer coefficients of the upper and lower portions of the tube were calculated separately from Rosson and Meyers (1965) correlation. The heat and mass transfer analogy was used to analyze the steam/noncondensable gas mixture boundary layer. Here, the Nusselt and Sherwood numbers in the gas phase were modified to incorporate the effects of condensate film roughness, suction, and developing flow. The predictions of the theoretical model for the experimental heat transfer coefficients at the top and bottom of the tube were reasonable. The calculated heat transfer coefficients at the top of the tube were higher than those at the bottom of it, as experimental results. As the temperature potential at the top of tube was lower than that at the bottom of it, the heat fluxes at the upper and lower portions of the tube were similar to each other. Generally speaking, however, the model predictions showed a good agreement with experimental data. The new empirical correlation proposed by Lee and Kim (2008) for the vertical tube was applied to the condensation of steam/noncondensable mixture in a horizontal tube. Nusselt theory and Chato correlation were used to calculate the heat transfer coefficients at top and bottom of the horizontal tube, respectively. The predictions of the new empirical correlation were good and very similar with the theoretical model. (author)

  1. Condensation of nano-refrigerant inside a horizontal tube

    Science.gov (United States)

    Darzi, Milad; Sadoughi, M. K.; Sheikholeslami, M.

    2018-05-01

    In this paper, condensing pressure drop of refrigerant-based nanofluid inside a tube is studied. Isobutene was selected as the base fluid while CuO nanoparticles were utilized to prepare nano-refrigerant. However, for the feasibility of nanoparticle dispersion into the refrigerant, Polyester oil (POE) was utilized as lubricant oil and added to the pure refrigerant by 1% mass fraction. Various values of mass flux, vapor quality, concentration of nanoparticle are investigated. Results indicate that adding nanoparticles leads to enhance frictional pressure drop. Nanoparticles caused larger pressure drop penalty at relatively lower vapor qualities which may be attributed to the existing condensation flow pattern such that annular flow is less influenced by nanoparticles compared to intermittent flow regime.

  2. An experimental study of aerosol penetration through horizontal tubes and strom-type loops

    International Nuclear Information System (INIS)

    Wong, F.S.; McFarland, A.R.; Anand, N.K.

    1996-01-01

    Because some designers of aerosol transport systems use the assumption that aerosol penetration through a system is maximized of the flow Reynolds number is 2,800, we have conducted tests to determine if such an assumption is appropriate. Although we do not believe that optimal performance of an aerosol sample transport system can be presented solely in terms of the Reynolds number, we have presented our results in terms of that parameter to compare our work with the results of an earlier study. Two types of experiments were performed. First, the penetration of liquid aerosol particles through horizontal tubes was experimentally investigated for a range of design and operational conditions. For a particle size of 10 μm aerodynamic diameter, the maximum penetration through a 6.7 mm diameter tube was associated with a Reynolds number of approximately 2,000; the maximum penetration through a tube of 15.9 mm occurred at a Reynolds number of about 3,000; and the maximum penetration through a 26.7 mm diameter tube occurred at about 4,000. It was also experimentally demonstrated that for a fixed flow rate through a horizontal tube, there is an optimum tube diameter for which the aerosol penetration is a maximum. An early study dealing with aerosol particle penetration through a 16.8 mm inside diameter loop of tubing (two vertical tubes, two horizontal tubes and three 90 degrees bends) suggested there was a fixed Reynolds number for optimal aerosol penetration independent of particle size. Those experiments were repeated here and the agreement with those tests is excellent. 16 refs., 8 figs., 3 tabs

  3. Nucleate boiling at the forced flow of binary non-azeotropic mixtures in horizontal tubes

    Directory of Open Access Journals (Sweden)

    Mezentseva N.N.

    2015-01-01

    Full Text Available Analysis of experimental values of heat transfer coefficients obtained through investigation of nucleate boiling of the two-component non-azeotropic mixtures inside the horizontal smooth tubes by various authors is presented. In the zone of nucleate boiling, the experimental data are in good agreement with the calculation dependence.

  4. Contribution to the heat transfer analysis of substitute refrigerants in evaporator tubes with smooth or enhanced tube surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kattan, N

    1997-12-31

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requests a good knowledge of heat transfer properties of substitute fluids. A new test facility has been built at the Laboratory for Industrial Energy Systems (LENI) to contribute to this international effort. It consists of two sets of concentric tubes allowing either annular or inside tube convective boiling with a counter current water flow heating to be studied. A new data base including heat transfer coefficients and pressure drop measurements for four new refrigerants (R123, R134A, R402A and R404A) and three older refrigerants (R11, R12 and R502) has been collected. Flow boiling measurements covered a broad range of mass velocities, vapor qualities and heat fluxes. Some of the tests included plain tubes and others enhanced surface tubes (microfilms from Wieland) in horizontal and vertical orientations. An improved Wilson plot technique, that covers both the transition and turbulent flow regimes of the water flowing in the annular channel for the inside tube boiling tests, is proposed to overcome the severe limitations of conventional Wilson plots, to improve accuracy and to facilitate data processing. Mean flow boiling heat transfer coefficients were measured for R12 and R134A evaporating inside a horizontal plain tube and for R11 and R123 evaporating inside a horizontal plain tube. Local flow boiling heat transfer coefficients were measured for : R134A, R123, R404A and R502 evaporating inside a horizontal plain tube, for R134A and R123 evaporating inside a horizontal microfin tube and for R134 evaporating inside a vertical microfin tube. In addition microfin heat transfer augmentation relative to plain tube test data was investigated. The measured heat transfer coefficients were compared to different existing inside tube flow boiling correlations. (author) figs., tabs., refs.

  5. CFD in supercritical water-cooled nuclear reactor (SCWR) with horizontal tube bundles

    Energy Technology Data Exchange (ETDEWEB)

    Zhi Shang, E-mail: zhi.shang@stfc.ac.uk [Science and Technology Facilities Council, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Lo, Simon, E-mail: simon.lo@uk.cd-adapco.com [CD-adapco, Trident House, Basil Hill Road, Didcot OX11 7HJ (United Kingdom)

    2011-11-15

    The commercial CFD code STAR-CD 4.02 is used as a numerical simulation tool for flows in the supercritical water-cooled nuclear reactor (SCWR). The basic heat transfer element in the reactor core can be considered as round tubes and tube bundles. Reactors with vertical or horizontal flow in the core can be found. In a vertically oriented core, symmetric characters of flow and heat transfer can be found and two-dimensional analyses are often performed. However, in a horizontally oriented core the flow and heat transfer are fully three-dimensional due to the buoyancy effect. In this paper, horizontal tubes and tube bundles at SCWR conditions are studied. Special STAR-CD subroutines were developed by the authors to correctly represent the dramatic change in physical properties of the supercritical water with temperature. From the study of single round tubes, the Speziale quadratic non-linear high-Re k-{epsilon} turbulence model with the two-layer model for near wall treatment is found to produce the best results in comparison with experimental data. In tube bundle simulations, it is found that the temperature is higher in the top half of the bundle and the highest tube wall temperature is located at the outside tubes where the flow rate is the lowest. The secondary flows across the bundle are highly complex. Their main effect is to even out the temperature over the area within each individual recirculation region. Similar analysis could be useful in design and safety studies to obtain optimum fuel rod arrangement in a SCWR.

  6. CFD in supercritical water-cooled nuclear reactor (SCWR) with horizontal tube bundles

    International Nuclear Information System (INIS)

    Shang, Zhi; Lo, Simon

    2009-01-01

    The commercial CFD code STAR-CD 4.02 is used as a numerical simulation tool for flows in the supercritical water-cooled nuclear reactor (SCWR). The basic heat transfer element in the reactor core can be considered as round tubes and tube bundles. Reactors with vertical or horizontal flow in the core can be found. In vertically oriented core, symmetric characters of flow and heat transfer can be found and two-dimensional analyses are often performed. However, in horizontally oriented core the flow and heat transfer are fully three-dimensional due to the buoyancy effect. In this paper, horizontal tubes and tube bundles at SCWR conditions are studied. Special STAR-CD subroutines were developed by the authors to correctly represent the dramatic change in physical properties of the supercritical water with temperature. From the study of single round tubes, the Speziale quadratic non-linear high-Re k-ε turbulence model with the two-layer model for near wall treatment is found to produce the best results in comparison with experimental data. In tube bundle simulations, it is found that the temperature is higher in the top half of the bundle and the highest tube wall temperature is located at the outside tubes where the flow rate is the lowest. The secondary flows across the bundle are highly complex. Their main effect is to even out the temperature over the area within each individual recirculating region. Similar analysis could be useful in design and safety studies to obtain optimum fuel rod arrangement in a SCWR. (author)

  7. Experimental investigation of thermal-hydraulic performance of PCCS with horizontal tube heat exchangers: single U-tube test

    International Nuclear Information System (INIS)

    Nakamura, Hideo; Anoda, Yoshinari; Arai, Kenji; Kurita, Tomohisa

    2000-01-01

    JAERI and JAPC started a cooperative study to verify performance of a PCCS (Passive Containment Cooling System) using horizontal heat exchanger for next-generation BWR in 1998. A test facility with a horizontal single U-tube was constructed in JAERI in 1999 to investigate fundamental condensation behavior under influences of non-condensable gas. Preliminary pre-test analyses were performed using RELAP5/ MOD3.2.1.2 code to expect the experimental outcomes by incorporating a correlation for condensation degradation because of non-condensable gas by Ueno et al. for better prediction. Preliminary results from both experiments (shakedown) and pre-test analyses indicated that the PCCS using horizontal U-tube heat exchanger is promising. Steam generated under assumed severe accident conditions; steam generation rate approx. = 1% core power, non-condensable gas concentration of 1% and simulated containment vessel pressure of 0.7 MPa, was totally condensed with a small differential pressure across inlet and outlet plenum. Experimental data will be accumulated to develop models and correlations for a better prediction of responses of the PCCS using horizontal heat exchanger during postulated severe accidents. (author)

  8. Efficiency in Microfinance Cooperatives

    Directory of Open Access Journals (Sweden)

    HARTARSKA, Valentina

    2012-12-01

    Full Text Available In recognition of cooperatives’ contribution to the socio-economic well-being of their participants, the United Nations has declared 2012 as the International Year of Cooperatives. Microfinance cooperatives make a large part of the microfinance industry. We study efficiency of microfinance cooperatives and provide estimates of the optimal size of such organizations. We employ the classical efficiency analysis consisting of estimating a system of equations and identify the optimal size of microfinance cooperatives in terms of their number of clients (outreach efficiency, as well as dollar value of lending and deposits (sustainability. We find that microfinance cooperatives have increasing returns to scale which means that the vast majority can lower cost if they become larger. We calculate that the optimal size is around $100 million in lending and half of that in deposits. We find less robust estimates in terms of reaching many clients with a range from 40,000 to 180,000 borrowers.

  9. [Comparison of dentomaxillary pantomography and periapical radiographs with horizontal tube shift in localizing the impacted teeth].

    Science.gov (United States)

    Wang, Sun; Fan, Lin-feng

    2005-04-01

    To compare the clinic value between dentomaxillary pantomography and periapical radiographs in localization of the impacted teeth. 43 impacted teeth were localized with both dentomaxillary pantomography technique and periapical radiographs with horizontal tube shift which is clinically widely used. And a comparison between the two methods was carried out using Chi square test. Both dentomaxillary pantomography and periapical radiographs with horizontal tube shift can relatively precisely demonstrate the position of the impacted teeth. The percentage of the cases which the image and the result of surgery was consistent in the two methods was 93.02% and 95.35% (P>0.05) respectively. There was no statistical difference between the two groups. Dentomaxillary pantomography can precisely localize the impacted teeth.

  10. Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification

    OpenAIRE

    Zheng Hui-Fan; Fan Xiao-Wei; Wang Fang; Liang Yao-Hua

    2013-01-01

    A theoretical analysis and experimental verification on the characteristics of a micro-fin evaporator using R290 and R717 as refrigerants were carried out. The heat capacity and heat transfer coefficient of the micro-fin evaporator were investigated under different water mass flow rate, different refrigerant mass flow rate, and different inner tube diameter of micro-fin evaporator. The simulation results of the heat transfer coefficient are fairly in good a...

  11. Assessment of horizontal in-tube condensation models using MARS code. Part I: Stratified flow condensation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Su [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Hong, Soon-Joon, E-mail: sjhong90@fnctech.com [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Ju-Yeop; Seul, Kwang-Won [Korea Institute of Nuclear Safety, 19 Kuseong-dong, Yuseong-gu, Daejon (Korea, Republic of); Park, Goon-Cherl [Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer This study collected 11 horizontal in-tube condensation models for stratified flow. Black-Right-Pointing-Pointer This study assessed the predictive capability of the models for steam condensation. Black-Right-Pointing-Pointer Purdue-PCCS experiments were simulated using MARS code incorporated with models. Black-Right-Pointing-Pointer Cavallini et al. (2006) model predicts well the data for stratified flow condition. Black-Right-Pointing-Pointer Results of this study can be used to improve condensation model in RELAP5 or MARS. - Abstract: The accurate prediction of the horizontal in-tube condensation heat transfer is a primary concern in the optimum design and safety analysis of horizontal heat exchangers of passive safety systems such as the passive containment cooling system (PCCS), the emergency condenser system (ECS) and the passive auxiliary feed-water system (PAFS). It is essential to analyze and assess the predictive capability of the previous horizontal in-tube condensation models for each flow regime using various experimental data. This study assessed totally 11 condensation models for the stratified flow, one of the main flow regime encountered in the horizontal condenser, with the heat transfer data from the Purdue-PCCS experiment using the multi-dimensional analysis of reactor safety (MARS) code. From the assessments, it was found that the models by Akers and Rosson, Chato, Tandon et al., Sweeney and Chato, and Cavallini et al. (2002) under-predicted the data in the main condensation heat transfer region, on the contrary to this, the models by Rosson and Meyers, Jaster and Kosky, Fujii, Dobson and Chato, and Thome et al. similarly- or over-predicted the data, and especially, Cavallini et al. (2006) model shows good predictive capability for all test conditions. The results of this study can be used importantly to improve the condensation models in thermal hydraulic code, such as RELAP5 or MARS code.

  12. Effect of surface roughness on heat transfer from horizontal immersed tubes in a fluidized bed

    International Nuclear Information System (INIS)

    Grewal, N.S.; Saxena, S.C.

    1979-01-01

    Experimental results of the total heat transfer coefficient between 12.7 mm dia copper tubes with four different rough surfaces and glass beads of three different sizes as taken in a 0.305 m x 0.305 m square fluidized bed as a function of fluidizing velocity are reported. The comparison of results for the rough and technically smooth tubes suggests that the heat transfer coefficient strongly depends on the ratio of pitch (P/sub f/) to the average particle diameter (d/sub p/), where P/sub f/ is the distance between the two corresponding points on consecutive threads or knurls. By the proper choice of (P/sub f//d/sub p/) ratio, the maximum total heat transfer coefficient for V-thread tubes (h/sub w/fb) can be increased by as much as 40 percent over the value for a smooth tube with the same outside diameter. However, for values of (P/sub f//d/sub p/) less than 0.95, the maximum heat transfer coefficient for the V-thread rough tubes is smaller than the smooth tube having the same outside diameter. The qualitative variation of the heat transfer coefficient for rough tubes with (P/sub f//d) is explained on the basis of the combined effect of contact geometry between the solid particles and the heat transfer surface, and the solids renewal rate at the surface. The present findings are critically compared with somewhat similar investigations from the literature on the heat transfer from horizontal or vertical rough tubes and tubes with small fins

  13. Microstructure and properties of TP2 copper tube with La microalloying by horizontal continuous casting

    Directory of Open Access Journals (Sweden)

    Jin-hu Wu

    2018-01-01

    Full Text Available The TP2 copper tube was prepared with La microalloying by horizontal continuous casting (HCC. The absorptivity of La and its effects on microstructure, tensile and corrosion properties of HCC TP2 copper tube were studied by means of the inductively coupled plasma optical emission spectrometer (ICP-OES, optical microscope (OM, scanning electron microscope (SEM and potentiodynamic polarization measurements. The results show that the absorptivity of La in the HCC TP2 copper tube is about 15% under antivacuum conditions due to the good chemical activities of La. The impurity elements in copper tube such as O, S, Pb and Si can be significantly reduced, and the average columnar dendrite spacing of the copper tube can also be reduced from 2.21 mm to 0.93 mm by adding La. The ultimate tensile strength and the elongation with and without La addition are almost unchanged. However, the annual corrosion rate of the HCC TP2 copper tube is reduced from 10.18 mm•a-1 to 9.37 mm•a-1 by the purification effect of trace La.

  14. Effects of roll waves on annular flow heat transfer at horizontal condenser tube

    International Nuclear Information System (INIS)

    Kondo, Masaya; Nakamura, Hideo; Anoda, Yoshinari; Sakashita, Akihiro

    2002-01-01

    Heat removal characteristic of a horizontal in-tube condensation heat exchanger is under investigation to be used for a passive containment cooling system (PCCS) of a next generation-type BWR. Flow regime observed at the inlet of the condenser tube was annular flow, and the local heat transfer rate was ∼20% larger than the prediction by the Dobson-Chato correlation. Roll waves were found to appear on the liquid film in the annular flow. The measured local condensation heat transfer rate was being closely related to the roll waves frequency. Based on these observations, a model is proposed which predicts the condensation heat transfer coefficient for annular flows around the tube inlet. The proposed model predicts well the influences of pressure, local gas-phase velocity and film thickness. (author)

  15. Establishment of Measurement Techniques for Sliding Bubble on a Horizontal Tube

    International Nuclear Information System (INIS)

    Kim, Yu-Na Kim; Park, Goon-Cherl; Cho, Hyoung-Kyu

    2015-01-01

    The mechanistic wall boiling model includes many parameters relevant with bubble behaviors, such as the bubble departure diameter, bubble lift-off diameter, bubble waiting time, etc. Although there have been a large number of studies investigating bubble behavior, the subjects of observation are almost bubbles on a plane or vertical tube. Since the bubble motion is highly influenced by the directions of gravitational force and the heating surfaces, it is expected that the bubble behavior on a horizontal tube is largely different from those on the other geometry. The heat exchanger of APR+ has horizontal U-tube configuration installed in a water pool, of which diameter is 50mm. The study aims to establish measurement techniques for sliding bubbles on a horizontal tube. The measurement parameters include the diameter, interface area, volume, and velocity of the bubble. Additionally, in order to analyze the force acting on the bubble, liquid velocity measurement method was proposed. This paper presents the procedure of the measurement; the phase separation technique, 3-D reconstruction technique, and velocity measurement techniques. For visualization of the sliding bubble behavior, bubble and liquid velocity measurement methods were established which use two high speed cameras and a continuous LASER for the PTV and PIV. Three steps for the bubble shape and velocity measurement (the phase separation, 3-D reconstruction, and velocity calculation), were successfully set up and verified. A PIV technique which uses two different time duration for two regions where the velocity difference is huge was proposed and tested. Using these methods, various information regarding a sliding bubble can be obtained such as bubble and liquid velocities, shape, volume, surface area etc

  16. Influence of stiffness on CHF for horizontal tubes under LPLF conditions

    Energy Technology Data Exchange (ETDEWEB)

    Baburajan, P.K. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Bisht, Govind Singh [Department of Mechanical Engineering, IIT Bombay, 400076 (India); Gaikwad, Avinash J. [Nuclear Safety Analysis Division, AERB, Niyamak Bhavan, 400094 (India); Prabhu, S.V., E-mail: svprabhu@iitb.ac.in [Department of Mechanical Engineering, IIT Bombay, 400076 (India)

    2014-10-01

    Highlights: • Effect of stiffness on the CHF in horizontal tube under LPLF conditions is studied. • CHF increases with the increase in stiffness. • Correlation for the prediction of CHF as a function of stiffness is developed. • Correlation for mass flux at CHF in terms of stiffness and initial mass flux is given. • RELAP5 is capable of predicting the effect of stiffness on CHF. - Abstract: Studies reported in the past on critical heat flux (CHF) are mostly limited to vertical flow, large channel diameter, high pressure and high mass flux. Since horizontal flow is commonly encountered in boiler tubes, refrigerating equipments and nuclear reactor fuel channels (PHWR), there is a need to understand horizontal flow CHF, generate sufficient experimental database and to develop reliable predictive method. Few studies are reported on the effect of upstream flow restrictions on flow instabilities and CHF. The present work investigates the effect of upstream flow restriction on CHF in horizontal flow at near atmospheric pressure conditions. In the present study, stiffness is defined as the ratio of upstream flow restriction pressure drop to the test section pressure drop. The classification of a flow boiling system as soft or stiff on the basis of quantification of the stiffness is attempted. Experimental data shows an increase in the CHF with the increase in the stiffness for a given initial mass flux. A correlation for the prediction of CHF under various stiffness conditions is developed. A correlation is suggested to predict the mass flux at CHF as a function of stiffness and initial mass flux. Modeling and transient analysis of the stiffness effect on CHF is carried out using the thermal hydraulic system code RELAP5. The predicted phenomena are in agreement with the experimental observations.

  17. Method for confirming flow pattern of gas-water flow in horizontal tubes under rolling state

    International Nuclear Information System (INIS)

    Luan Feng; Yan Changqi

    2008-01-01

    An experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state. It was found that the pressure drop of two phase flow was with an obvious periodical characteristic. The flow pattern of the gas-water flow was distinguished according to the characteristics of the pressure drop in this paper. It was proved that the characteristics of the pressure drop can distinguish the flow pattern of gas-water flow correctly through comparing with the result of careful observation and high speed digital camera. (authors)

  18. Heat transfer in the post-dryout region of vertical and horizontal tubes uniformly heated

    International Nuclear Information System (INIS)

    Kastner, W.; Koehler, W.; Kraetzer, W.

    1983-11-01

    Increased knowledge of the heat transfer in the post-dryout region is required for novel design of environmentally acceptable power plant technologies (e.g. fluidized bed combustion) and further development of proved steam generators. In particular, the influence of tube orientation and diameter are of consequence. Relating to the onset of critical boiling conditions and the heat transfer in the post-dryout region these aspects were investigated performing 357 tests which cover the operating conditions of fossil fired steam generators. In certain regions of parameters significant differences of the heat transfer behaviour of horizontal and vertical steam generator tubes occured. The experimental results were analysed and compared with theoretical models which were taken from the literature or developed within the frame of this project. (orig.) [de

  19. Effect of liquid nitrogen flow rate on solidification of stagnant water in a horizontal tube

    International Nuclear Information System (INIS)

    Ibrahim, S.M.

    1995-01-01

    Five experiments are conducted to study the effect of liquid nitrogen flow rate on the solidification of stagnant water inside a horizontal stainless steel tube of inner diameter 19.6 cm and 12 mm thick. This tube simulates the down-comer of the nuclear reactor ET-R R-1. The apparatus design is mentioned more detail description. The results show that for the first experiment where the liquid nitrogen flow rate is 30 1/hr, the progress of solidification of water has stopped at a diameter of 12 cm. By increasing the flow rate from 30 1/hr to 40,50 and 60 1/hr, the time of freezing the water inside the tube is decreased from 86 to 67 and 60 minutes respectively. By increasing the liquid nitrogen flow rate to 70 1/hr, there is no much effect on the time of frozen. In all experiments, where the solidification is happened, the ice block formed inside the tube is subjected to a pressure of 3 at mg least, and is succeed to withstand this pressure without any leak. 7 figs

  20. Islamic Microfinance: an Interest free Microfinance Model for Poverty Alleviation

    Directory of Open Access Journals (Sweden)

    Amit Kumar Chakrabarty

    2015-01-01

    Full Text Available This theoretical paper deals with Islamic microfinance and its rationality in Indian context as a panacea of Muslim poverty. Conventional microfinance system is very effective to alleviate poverty of developing countries. But it could not touch all community of people because of ‘interest’ component in debt and high degree of interest. Muslims dislike that microfinance which is based on ‘interest’ as it is strictly prohibited in Islam. Therefore the motto of financial inclusion is out of reach through conventional microfinance. An alternative interest free microfinance model has been developed in some part of world to include all Muslim poor people within the banking system. India is yet to adopt Islamic microfinance though 20% of total population is Muslim. The author strongly opines that India should adopt Islamic microfinance as a tool for poverty alleviation of Muslims as well as other communities.

  1. Measurements of local liquid velocity and interfacial parameters of air-water bubbly flows in a horizontal tube

    International Nuclear Information System (INIS)

    Yang Jian; Zhang Mingyuan; Zhang Chaojie; Su Yuliang

    2002-01-01

    Distribution of local kinematic parameters of air-water bubbly flows in a horizontal tube with an ID of 35 mm was investigated. The local liquid velocity was measured with a cylindrical hot film probe, and local void fraction, bubble frequency and bubble velocity were measured with a double-sensor probe. It was found that the axial liquid velocity has a same profile as that of single liquid phase flow in the lower part of the tube, and it suffers a sudden reduction in the upper part of the tube. With increasing airflow rate, the liquid velocity would increase in the lower part of the tube, and further decrease at the upper part of the tube, respectively. Most bubbles are congested at the upper part of the tube, and the void fraction and bubble frequencies have similar profile and both are asymmetrical with the tube axis with their maximum values located near the upper tube wall

  2. Field synergy characteristics in condensation heat transfer with non-condensable gas over a horizontal tube

    Directory of Open Access Journals (Sweden)

    Junxia Zhang

    2017-05-01

    Full Text Available Field synergy characteristics in condensation heat transfer with non-condensable gas (NCG over a horizontal tube were numerically simulated. Consequently, synergy angles between velocity and pressure or temperature gradient fields, gas film layer thickness, and induced velocity and shear stress on gas–liquid interface were obtained. Results show that synergy angles between velocity and temperature gradient fields are within 73.2°–88.7° and ascend slightly with the increment in mainstream velocity and that the synergy is poor. However, the synergy angle between velocity and pressure gradient fields decreases intensively with the increase in mainstream velocity at θ ≤ 30°, thereby improving the pressure loss. As NCG mass fraction increases, the gas film layer thickness enlarges and the induced velocity and shear stress on gas–liquid interface decreases. The synergy angles between velocity and temperature gradient fields increase, and the synergy angles between velocity and pressure gradient fields change at θ = 70°, decrease at θ 70°. When the horizontal tube circumference angle increases, the synergy angles between velocity and temperature or pressure gradient fields decrease, the synergy between velocity and pressure fields enhances, and the synergy between velocity and temperature fields degrades.

  3. What makes microfinance happen?

    Directory of Open Access Journals (Sweden)

    Manuel Antonio Jiménez Castillo

    2015-12-01

    Full Text Available In this paper we have attempted to shed light on what makes development happen from those determinants that enable microfinance work as an effective tool to eradicate poverty. The effectiveness of such instrument in the generation of wealth to the poorest class demand overcoming the minimalist approach that condemns its practices to a mere provision of microfinancial services. This hypothesis will be analytically and empirically proven assuming human development as a cause and not only as an outcome of the microfinance success. To such end, two regression lines were designed where variables such as education, health and food security proved to be explanatory determinant to explain income behaviour for those beneficiaries of the microfinance programs.

  4. Numerical investigation of supercritical LNG convective heat transfer in a horizontal serpentine tube

    Science.gov (United States)

    Han, Chang-Liang; Ren, Jing-Jie; Dong, Wen-Ping; Bi, Ming-Shu

    2016-09-01

    The submerged combustion vaporizer (SCV) is indispensable general equipment for liquefied natural gas (LNG) receiving terminals. In this paper, numerical simulation was conducted to get insight into the flow and heat transfer characteristics of supercritical LNG on the tube-side of SCV. The SST model with enhanced wall treatment method was utilized to handle the coupled wall-to-LNG heat transfer. The thermal-physical properties of LNG under supercritical pressure were used for this study. After the validation of model and method, the effects of mass flux, outer wall temperature and inlet pressure on the heat transfer behaviors were discussed in detail. Then the non-uniformity heat transfer mechanism of supercritical LNG and effect of natural convection due to buoyancy change in the tube was discussed based on the numerical results. Moreover, different flow and heat transfer characteristics inside the bend tube sections were also analyzed. The obtained numerical results showed that the local surface heat transfer coefficient attained its peak value when the bulk LNG temperature approached the so-called pseudo-critical temperature. Higher mass flux could eliminate the heat transfer deteriorations due to the increase of turbulent diffusion. An increase of outer wall temperature had a significant influence on diminishing heat transfer ability of LNG. The maximum surface heat transfer coefficient strongly depended on inlet pressure. Bend tube sections could enhance the heat transfer due to secondary flow phenomenon. Furthermore, based on the current simulation results, a new dimensionless, semi-theoretical empirical correlation was developed for supercritical LNG convective heat transfer in a horizontal serpentine tube. The paper provided the mechanism of heat transfer for the design of high-efficiency SCV.

  5. Effect of crevice environment PH on corrosion damage of horizontal steam generator tubes

    International Nuclear Information System (INIS)

    Brozova, A.; Burda, J.; Splichal, K.

    2002-01-01

    In support of a project on lifetime calculation experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K Iscc , and the crack growth rate were made to predict evolution of damage in tube walls. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that the material of SG tubes is sensitive to transgranular environmentally assisted cracking in the three basic concentrated environments used, alkaline, neutral and acid. The most corrosive medium was the acid environment. The crack initiated practically immediately after acid environment exposure. The initiation process takes a long time in neutral and alkaline environments. The K Iscc values for environmentally assisted crack growth rate in alkaline and neutral concentrated environment were essentially the same. The crack growth rate was slightly higher for the neutral environment than for the alkaline one. Fracture patterns for the both environments were similar. (author)

  6. Experimental Investigation of Natural Convection into a Horizontal Annular Tube with Porous Medium Effects

    Directory of Open Access Journals (Sweden)

    Saad Najeeb Shehab

    2018-12-01

    Full Text Available In this work, an experimental investigation has been done for heat transfer by natural-convection through a horizontal concentric annulus with porous media effects. The porous structure in gap spacing consists of a glass balls and replaced by plastic (PVC balls with different sizes. The outer surface of outer tube is isothermally cooled while the outer surface of inner tube is heated with constant heat flux condition. The inner tube is heated with different supplied electrical power levels. Four different radius ratios of annulus are used. The effects of porous media material, particles size and annulus radius ratio on heat dissipation in terms of average Nusselt number have been analyzed. The experimental results show that the average Nusselt number increases with increasing annulus radius ratio and particle diameter for same porous media material. Furthermore, two empirical correlations of average Nusselt number with average Rayleigh number for glass and PVC particles are developed. The present experimental results are compared with previously works and good correspondence is showed.

  7. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-10-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  8. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-07-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  9. Aid and microfinance

    NARCIS (Netherlands)

    Hermes, Niels; Lensink, Robert

    2015-01-01

    Microfinance institutions (MFIs) focus on providing financial services to poor households who are excluded from the formal financial system. Having access to finance is crucial for the poor as this helps them to smooth their consumption, generate business opportunities, and improve their inclusion

  10. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure

    Science.gov (United States)

    Yang, Mei

    2016-01-01

    Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k−ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared. PMID:27458729

  11. Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

    Science.gov (United States)

    Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

    2016-06-01

    Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

  12. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure.

    Directory of Open Access Journals (Sweden)

    Mei Yang

    Full Text Available Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k-ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared.

  13. The effect of diameter on vertical and horizontal flow boiling crisis in a tube cooled by Freon-12

    International Nuclear Information System (INIS)

    Merilo, M.; Ahmad, S.Y.

    1979-03-01

    The influence of test section orientation and diameter on flow boiling crisis occurring in tubes has been studied experimentally using Freon-12 as a coolant. At low mass flux the critical heat flux (CHF) was lower in horizontal flow than in vertical. As either the liquid or vapour velocity, or both, were increased the vertical and horizontal CHF results converged. Above a mass flux of 4 Mg.m -2 .s -1 the results were essentially identical. The effect of tube diameter on boiling crisis in general depends crucially on the parameters which are maintained constant when the comparison is made. (author)

  14. Reliability of horizontal and vertical tube shift techniques in the localisation of supernumerary teeth.

    Science.gov (United States)

    Mallineni, S K; Anthonappa, R P; King, N M

    2016-12-01

    To assess the reliability of the vertical tube shift technique (VTST) and horizontal tube shift technique (HTST) for the localisation of unerupted supernumerary teeth (ST) in the anterior region of the maxilla. A convenience sample of 83 patients who attended a major teaching hospital because of unerupted ST was selected. Only non-syndromic patients with ST and who had complete clinical and radiographic and surgical records were included in the study. Ten examiners independently rated the paired set of radiographs for each technique. Chi-square test, paired t test and kappa statistics were employed to assess the intra- and inter-examiner reliability. Paired sets of 1660 radiographs (830 pairs for each technique) were available for the analysis. The overall sensitivity for VTST and HTST was 80.6 and 72.1% respectively, with slight inter-examiner and good intra-examiner reliability. Statistically significant differences were evident between the two localisation techniques (p HTST in the anterior region of the maxilla.

  15. Evaporation heat transfer of carbon dioxide at low temperature inside a horizontal smooth tube

    Science.gov (United States)

    Yoon, Jung-In; Son, Chang-Hyo; Jung, Suk-Ho; Jeon, Min-Ju; Yang, Dong-Il

    2017-05-01

    In this paper, the evaporation heat transfer coefficient of carbon dioxide at low temperature of -30 to -20 °C in a horizontal smooth tube was investigated experimentally. The test devices consist of mass flowmeter, pre-heater, magnetic gear pump, test section (evaporator), condenser and liquid receiver. Test section is made of cooper tube. Inner and outer diameter of the test section is 8 and 9.52 mm, respectively. The experiment is conducted at mass fluxes from 100 to 300 kg/m2 s, saturation temperature from -30 to -20 °C. The main results are summarized as follows: In case that the mass flux of carbon dioxide is 100 kg/m2 s, the evaporation heat transfer coefficient is almost constant regardless of vapor quality. In case of 200 and 300 kg/m2 s, the evaporation heat transfer coefficient increases steadily with increasing vapor quality. For the same mass flux, the evaporation heat transfer coefficient increases as the evaporation temperature of the refrigerant decreases. In comparison of heat transfer correlations with the experimental result, the evaporation heat transfer correlations do not predict them exactly. Therefore, more accurate heat transfer correlation than the previous one is required.

  16. Research of heat transfer of staggered horizontal bundles of finned tubes at free air convection

    Science.gov (United States)

    Novozhilova, A. V.; Maryna, Z. G.; Samorodov, A. V.; Lvov, E. A.

    2017-11-01

    The study of free-convective processes is important because of the cooling problem in many machines and systems, where other ways of cooling are impossible or impractical. Natural convective processes are common in the steam turbine air condensers of electric power plants located within the city limits, in dry cooling towers of circulating water systems, in condensers cooled by air and water, in radiators cooling oil of power electric transformers, in emergency cooling systems of nuclear reactors, in solar power, as well as in air-cooling of power semiconductor energy converters. All this makes actual the synthesis of the results of theoretical and experimental research of free convection for heat exchangers with finned tube bundles. The results of the study of free-convection heat transfer for two-, three- and four-row staggered horizontal bundles of industrial bimetallic finned tubes with finning factor of 16.8 and equilateral tubes arrangement are presented. Cross and diagonal steps in the bundles are the same: 58; 61; 64; 70; 76; 86; 100 mm, which corresponds to the relative steps: 1.042; 1.096; 1.152; 1.258; 1.366; 1.545; 1.797. These steps are standardized for air coolers. An equation for calculating the free-convection heat transfer, taking into account the influence of geometrical parameters in the range of Rayleigh number from 30,000 to 350,000 with an average deviation of ± 4.8%, has been obtained. The relationship presented in the article allows designing a wide range of air coolers for various applications, working in the free convection modes.

  17. Bubble-assisted film evaporation correlation for saline water at sub-atmospheric pressures in horizontal-tube evaporator

    KAUST Repository

    Shahzad, Muhammad Wakil; Myat, Aung; Chun, Won Gee; Ng, Kim Choon

    2013-01-01

    film boiling on horizontal tubes, but working at low pressures of 0.93-3.60 kPa (corresponding solution saturation temperatures of 279-300 K) as well as seawater salinity of 15,000 to 90,000 mg/l or ppm. Owing to a dearth of literature on film

  18. MICROFINANCE AND POOREST COUNTRIES

    OpenAIRE

    阿部, 清司

    2004-01-01

    The world is divided into developing and developed countries. There are two kinds of banks: conventional ones and unconventional. Commercial banks are usually based on mutual distrust, while new unconventional banks, microfinances, are based on mutual trust. The origin of micro finance is deeply rooted in Asia. In 1976, Grameen Bank in Bangladesh was founded by Dr. Muhammad Yunus. It reverses conventional banking practice by removing the need for collateral. It creates a banking system based ...

  19. Heat transfer analysis and effects of feeding tubes arrangement, falling film behavior and backsplash on ice formation around horizontal tubes bundles

    International Nuclear Information System (INIS)

    Sait, Hani Hussain

    2013-01-01

    Highlights: • Ice shape around the tubes. • Effects of accumulation of ice around the tubes. • Effects of parallel and series tubes arrangements. • Effects of ice accumulated around the tube surfaces. • Effects of backsplash on ice formation. - Abstract: Excessive electrical load has recently get a lot of attention from electric companies specially in hot countries like Saudi Arabia, where air-conditioning load represents about 75% from the total electrical load. Energy storage by freezing is one of the methods that used to tackle this issue. Ice is formed around horizontal cold tubes that are subjected to falling film of water. Ice quantity is measured, photographed and studied. In this studied the coolant inside the tubes flows in series tube arrangement. The results are compared with previous study in which parallel arrangement was used. In addition the falling film behavior and the resulted backsplash are also investigated. A mathematical model to predict ice formation around the tube is proposed. Comparison of the results of the model with that of the experiments showed that the agreement between the two is acceptable. The results also show a quite reasonable quantity of ice is formed in a short time and the series arrangement is more efficient than parallel one. The falling film shapes and its backsplash has also affected the ice formation

  20. Does Microfinance Reduce Income Inequality?

    NARCIS (Netherlands)

    Hermes, Niels

    2014-01-01

    This study addresses the question whether participation of the poor in microfinance contributes to reducing a country’s level of income inequality. Using data from 70 developing countries, we show that higher levels of microfinance participation are indeed associated with a reduction of the income

  1. Characterization of Dosimetry of the BMRR Horizontal Thimble Tubes and Broad Beam Facility.

    Energy Technology Data Exchange (ETDEWEB)

    Hu,J.P.; Reciniello, R.N.; Holden, N.E.

    2008-05-05

    The Brookhaven Medical Research Reactor was a 5 mega-watt, light-water cooled and heavy-graphite moderated research facility. It has two shutter-equipped treatment rooms, three horizontally extended thimble tubes, and an ex-core broad beam facility. The three experimental thimbles, or activation ports, external to the reactor tank were designed for several uses, including the investigations on diagnostic and therapeutic methods using radioactive isotopes of very short half-life, the analysis of radiation exposure on tissue-equivalent materials using a collimated neutron beam, and the evaluation of dose effects on biological cells to improve medical treatment. At the broad beam facility where the distribution of thermal neutrons was essential uniform, a wide variety of mammalian whole-body exposures were studied using animals such as burros or mice. Also studied at the broad beam were whole-body phantom experiments, involving the use of a neutron or photon beam streaming through a screen to obtain the flux spectrum suitable for dose analysis on the sugar-urea-water mixture, a tissue-equivalent material. Calculations of the flux and the dose at beam ports based on Monte Carlo particle-transport code were performed, and measurements conducted at the same tally locations were made using bare or cadmium-covered gold foils. Analytical results, which show good agreement with measurement data, are presented in the paper.

  2. Cooling performance assessment of horizontal earth tube system and effect on planting in tropical greenhouse

    International Nuclear Information System (INIS)

    Mongkon, S.; Thepa, S.; Namprakai, P.; Pratinthong, N.

    2014-01-01

    Graphical abstract: - Highlights: • The cooling ability of HETS is studied for planting in tropical greenhouse. • The effective of system was moderate with COP more than 2.0. • Increasing diameter and air velocity increase COP more than other parameters. • The plant growth with HETS was significantly better than no-HETS plant. - Abstract: The benefit of geothermal energy is used by the horizontal earth tube system (HETS); which is not prevalent in tropical climate. This study evaluated geothermal cooling ability and parameters studied in Thailand by mathematical model. The measurement of the effect on plant cultivation was carried out in two identical greenhouses with 30 m 2 of greenhouse volume. The HETS supplied cooled air to the model greenhouse (MGH), and the plant growth results were compared to the growth results of a conventional greenhouse (CGH). The prediction demonstrated that the coefficient of performance (COP) in clear sky day would be more than 2.0 while in the experiment it was found to be moderately lower. The parameters study could be useful for implementation of a system for maximum performance. Two plants Dahlias and head lettuce were grown satisfactory. The qualities of the plants with the HETS were better than the non-cooled plants. In addition, the quality of production was affected by variations of microclimate in the greenhouses and solar intensity throughout the cultivation period

  3. Mechanistic multidimensional analysis of two-phase flow in horizontal tube with 90 deg elbow

    International Nuclear Information System (INIS)

    Tselishcheva, E.A.; Antal, St.P.; Podowski, M.Z.; Marshall, S.

    2007-01-01

    The development of modeling and simulation capabilities of two-phase flow and heat transfer is very important for the design, operation and safety of nuclear reactors. Whereas a significant progress in this field has been made over the recent years, further advancements are clearly needed for new concepts of advanced (Generation-IV in particular) reactors. Difficulties in analyzing gas/liquid flows are due to the fact that such two-phase mixtures can assume several different flow patterns, each characterized by flow-regime specific interfacial phenomena of mass, momentum and energy transfer. The level of difficulty increases even further in the case of a complex tube geometries and spatial orientations. The purpose of this paper is to discuss the results of the analysis of a two-phase flow in a horizontal pipe with a 90-degree elbow. The overall objective of the present work is the development of a 3-dimensional computational model of a two-phase high-Reynolds number turbulent flow. The overall new model has been encoded in the next-generation Computational Multiphase Fluid Dynamics (CMFD) computer code, NPHASE. The model has been tested parametrically and the results of NPHASE calculations have been compared against experimental data. It has been demonstrated that the proposed model is consistent both physically and numerically, the predictions are in a reasonable agreement with the measurements

  4. Coupling of standard condensing nuclear power stations to horizontal aluminium tubes multieffect distillation plants

    International Nuclear Information System (INIS)

    Adar, J.

    1977-01-01

    No large nuclear back-pressure turbines are available to-day. Standard condensing nuclear turbines could operate continuously with a back-pressure of up to 7'' Hg, exhausting huge amounts of steam at 56degC-64degC with a loss of electricity production of only 6%-10%. The horizontal aluminium tube multieffect distillation process developed by 'Israel Desalination Engineering Ltd' is very suitable for the use of such low-grade heat. A special flash-chamber loop constitutes a positive barrier against any possible contamination being carried over by the steam exhausted from the turbine to the desalination plant. The operation is designed to be flexible so that the power plant can be operated either in conjunction with the desalination plant or as a single purpose plant. Flow sheets, heat and mass balances have been prepared for eight different combinations of plants. Only standard equipment is being used in the power plant. The desalination plant consists of 6 to 12 parallel double lines, each of them similar to a large prototype now being designed. Water production varies between 50 and 123 MGD and water cost between 90 and 137 c/1000 gallons. Costs are based on actual bids

  5. The modelling of condensation in horizontal tubes and the comparison with experimental data

    Directory of Open Access Journals (Sweden)

    Bryk Rafał

    2017-01-01

    Full Text Available The condensation in horizontal tubes plays an important role in determining the operation mode of passive safety systems of modern nuclear power plants. In this paper, two different approaches for modelling of this phenomenon are compared and verified against experimental data. The first approach is based on the flow regime map developed by Tandon. Depending on the regime, the heat transfer coefficient is calculated according to corresponding semi-empirical correlation. The second approach uses a general, fully empirical correlation proposed by Shah. Both models are developed with utilization of the object-oriented, equation-based Modelica language and the open-source Open-Modelica environment. The results are compared with data obtained during a large scale integral test, simulating a Loss of Coolant Accident scenario performed at the dedicated Integral Test Facility Karlstein (INKA which was built at the Components Testing Department of AREVA in Karlstein, Germany. The INKA facility was designed to test the performance of the passive safety systems of KERENA, the new AREVA boiling water reactor design. INKA represents the KERENA containment with a volume scaling of 1:24. Components heights and levels over the ground are in the full scale. The comparison of simulations results shows a good agreement.

  6. Experimental study on the minimum drag coefficient of supercritical pressure water in horizontal tubes

    International Nuclear Information System (INIS)

    Lei, Xianliang; Li, Huixiong; Guo, YuMeng; Zhang, Qing; Zhang, Weiqiang; Zhang, Qian

    2016-01-01

    Highlights: • The minimum drag coefficient phenomenon (MDC) has been observed and further investigated. • Effects of heat flux, mass flux and pressure to MDC have been discussed. • A series of comparisons between existing correlations and data have been conducted. • Two correlations of drag coefficient are proposed for isothermal and nonisothermal flow. - Abstract: Hydraulic resistance and its components are of great importance for understanding the turbulence nature of supercritical fluid and establishing prediction methods. Under supercritical pressures, the hydraulic resistance of the fluid exhibits a “pit” in the regions near its pseudo-critical point, which is hereafter called the minimum drag coefficient phenomenon. However, this special phenomenon was paid a little attention before. Hence systematical experiments have been carried out to investigate the hydraulic resistance of supercritical pressure water in both adiabatic and heated horizontal tubes. Parametric effects of heat flux, pressure and mass fluxes to drag coefficient are further compared. It is found that almost all of the existing correlations don’t agree well with the experimental data due to the insufficient consideration of thermal-properties near the pseudocritical point. Two correlations of the drag coefficients are finally proposed by introducing the new variable of the derivative of density with respect to temperature or Prandtl number, which can better predict the drag coefficient of isothermal and nonisothermal flow respectively.

  7. Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification

    Directory of Open Access Journals (Sweden)

    Zheng Hui-Fan

    2013-01-01

    Full Text Available A theoretical analysis and experimental verification on the characteristics of a micro-fin evaporator using R290 and R717 as refrigerants were carried out. The heat capacity and heat transfer coefficient of the micro-fin evaporator were investigated under different water mass flow rate, different refrigerant mass flow rate, and different inner tube diameter of micro-fin evaporator. The simulation results of the heat transfer coefficient are fairly in good agreement with the experimental data. The results show that heat capacity and the heat transfer coefficient of the micro-fin evaporator increase with increasing logarithmic mean temperature difference, the water mass flow rate and the refrigerant mass flow rate. Heat capacity of the micro-fin evaporator for diameter 9.52 mm is higher than that of diameter 7.00 mm with using R290 as refrigerant. Heat capacity of the micro-fin evaporator with using R717 as refrigerant is higher than that of R290 as refrigerant. The results of this study can provide useful guidelines for optimal design and operation of micro-fin evaporator in its present or future applications.

  8. Visualization of two-phase gas-liquid flow regimes in horizontal and slightly-inclined circular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia Alves [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: livia@lasme.coppe.ufrj.br; Cunha Filho, Jurandyr; Su, Jian [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program], Emails: cunhafilho@lasme.coppe.ufrj.br, sujian@lasme.coppe.ufrj.br; Faccini, Jose Luiz Horacio [Nuclear Engineering Institute (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)], E-mail: faccini@ien.gov.br

    2010-07-01

    In this paper a flow visualization study was performed for two-phase gas-liquid flow in horizontal and slightly inclined tubes. The test section consists of a 2.54 cm inner diameter stainless steel circular tube, followed by a transparent acrylic tube with the same inner diameter. The working fluids were air and water, with liquid superficial velocities ranging from 0:11 to 3:28 m/s and gas superficial velocities ranging from 0:27 to 5:48 m/s. Flow visualization was executed for upward flow at 5 deg and 10 deg and downward flow at 2:5 deg, 5 deg and 10 deg, as well as for horizontal flow. The visualization technique consists of a high-speed digital camera that records images at rates of 125 and 250 frames per second of a concurrent air-water mixture through a transparent part of the tube. From the obtained images, the flow regimes were identified (except for annular flow), observing the effect of inclination angles on flow regime transition boundaries. Finally, the experimental results were compared with empirical and theoretical flow pattern maps available in literature. (author)

  9. Risk management in microfinance institutions

    OpenAIRE

    Batin, Artyom

    2014-01-01

    In the following paper I have tried to find the correlation between type of ownership and effective risk management in the operations of microfinance institutions in India. The results found are consistent with the current findings of how the type of ownership does not impact both the financial or social performance of MFIs. Dataset of 72 MFIs was acquired from the Microfinance Information Exchange on MFIs and evaluated using an OLS regression. The results show that the type of ownership insi...

  10. The evaluation of validity of the RELAP5/Mod3 flow regime map for horizontal small diameter tubes at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Agafonova, N. [St. Petersburg State Technical Univ. (Russian Federation); Banati, J. [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    RELAP5/MOD3 code was developed for Western type power water reactors with vertical steam generators. Thus, this code should be validated also for WWER design with horizontal steam generators. In application for horizontal steam generators the situation with two-phase flow inside small diameter tubes is possible when the first circuit pressure drops in accident below the pressure level in the boiling water. It is known that computer codes have not always modelled correctly the two-phase flow inside horizontal tubes at low pressures (less than 4-6 MPa). It may be the result of erroneous prediction of the flow regime. Correct prediction of the flow regime is especially important for the fully or partly stratified flow in horizontal tubes. The aim of this study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal small diameter tubes. `Small diameter tube` means according RELAP5/MOD3 that the inner diameter of the tube is less (or equal) than 0.018 m. The inner tube diameter in horizontal steam generators is equal 0.013 m. (orig.). 19 refs.

  11. The evaluation of validity of the RELAP5/Mod3 flow regime map for horizontal small diameter tubes at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Agafonova, N [St. Petersburg State Technical Univ. (Russian Federation); Banati, J [Lappeenranta Univ. of Technology (Finland)

    1998-12-31

    RELAP5/MOD3 code was developed for Western type power water reactors with vertical steam generators. Thus, this code should be validated also for WWER design with horizontal steam generators. In application for horizontal steam generators the situation with two-phase flow inside small diameter tubes is possible when the first circuit pressure drops in accident below the pressure level in the boiling water. It is known that computer codes have not always modelled correctly the two-phase flow inside horizontal tubes at low pressures (less than 4-6 MPa). It may be the result of erroneous prediction of the flow regime. Correct prediction of the flow regime is especially important for the fully or partly stratified flow in horizontal tubes. The aim of this study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal small diameter tubes. `Small diameter tube` means according RELAP5/MOD3 that the inner diameter of the tube is less (or equal) than 0.018 m. The inner tube diameter in horizontal steam generators is equal 0.013 m. (orig.). 19 refs.

  12. Measurement of subcooled boiling pressure drop and local heat transfer coefficient in horizontal tube under LPLF conditions

    International Nuclear Information System (INIS)

    Baburajan, P.K.; Bisht, G.S.; Gupta, S.K.; Prabhu, S.V.

    2013-01-01

    Highlights: ► Measured subcooled boiling pressure drop and local heat transfer coefficient in horizontal tubes. ► Infra-red thermal imaging is used for wall temperature measurement. ► Developed correlations for pressure drop and local heat transfer coefficient. -- Abstract: Horizontal flow is commonly encountered in boiler tubes, refrigerating equipments and nuclear reactor fuel channels of pressurized heavy water reactors (PHWR). Study of horizontal flow under low pressure and low flow (LPLF) conditions is important in understanding the nuclear core behavior during situations like LOCA (loss of coolant accidents). In the present work, local heat transfer coefficient and pressure drop are measured in a horizontal tube under LPLF conditions of subcooled boiling. Geometrical parameters covered in this study are diameter (5.5 mm, 7.5 mm and 9.5 mm) and length (550 mm, 750 mm and 1000 mm). The operating parameters varied are mass flux (450–935 kg/m 2 s) and inlet subcooling (29 °C, 50 °C and 70 °C). Infra-red thermography is used for the measurement of local wall temperature to estimate the heat transfer coefficient in single phase and two phase flows with water as the working medium at atmospheric pressure. Correlation for single phase diabatic pressure drop ratio (diabatic to adiabatic) as a function of viscosity ratio (wall temperature to fluid temperature) is presented. Correlation for pressure drop under subcooled boiling conditions as a function of Boiling number (Bo) and Jakob number (Ja) is obtained. Correlation for single phase heat transfer coefficient in the thermal developing region is presented as a function of Reynolds number (Re), Prandtl number (Pr) and z/d (ratio of axial length of the test section to diameter). Correlation for two phase heat transfer coefficient under subcooled boiling condition is developed as a function of boiling number (Bo), Jakob number (Ja) and Prandtl number (Pr)

  13. Evaluation of microfinance projects.

    Science.gov (United States)

    Johnson, S

    1999-08-01

    This paper criticizes the quick system proposed by Henk Moll for evaluating microfinance projects in the article ¿How to Pre-Evaluate Credit Projects in Ten Minutes¿. The author contended that there is a need to emphasize the objectives of the project. The procedure used by Moll, he contended, is applicable only to projects that have only two key objectives, such as credit operations, and the provision of services. Arguments are presented on the three specific questions proposed by Moll, ranging from the availability of externally audited financial reports, the performance of interest rate on loans vis-a-vis the inflation rate, and the provision of loans according to the individual requirements of the borrowers. Lastly, the author emphasizes that the overall approach is not useful and suggests that careful considerations should be observed in the use or abuse of a simple scoring system or checklist such as the one proposed by Moll.

  14. Characteristics of two-phase flow pattern transitions and pressure drop of five refrigerants in horizontal circular small tubes

    Energy Technology Data Exchange (ETDEWEB)

    Pamitran, A.S. [Department of Mechanical Engineering, University of Indonesia, Kampus Baru UI, Depok 16424 (Indonesia); Choi, Kwang-Il [Graduate School, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Oh, Jong-Taek [Department of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1, Dunduk-Dong, Yeosu, Chonnam 550-749 (Korea); Hrnjak, Pega [Department of Mechanical Science and Engineering, ACRC, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801 (United States)

    2010-05-15

    An experimental investigation on the characteristics of two-phase flow pattern transitions and pressure drop of R-22, R-134a, R-410A, R-290 and R-744 in horizontal small stainless steel tubes of 0.5, 1.5 and 3.0 mm inner diameters is presented. Experimental data were obtained over a heat flux range of 5-40 kW/m{sup 2}, mass flux range of 50-600 kg/(m{sup 2} s), saturation temperature range of 0-15 C, and quality up to 1.0. Experimental data were evaluated with Wang et al. and Wojtan et al. [Wang, C.C., Chiang, C.S., Lu, D.C., 1997. Visual observation of two-phase flow pattern of R-22, R-134a, and R-407C in a 6.5-mm smooth tube. Exp. Therm. Fluid Sci. 15, 395-405; Wojtan, L., Ursenbacher, T., Thome, J.R., 2005. Investigation of flow boiling in horizontal tubes: part I - a new diabatic two-phase flow pattern map. Int. J. Heat Mass Transfer 48, 2955-2969.] flow pattern maps. The effects of mass flux, heat flux, saturation temperature and inner tube diameter on the pressure drop of the working refrigerants are reported. The experimental pressure drop was compared with the predictions from some existing correlations. A new two-phase pressure drop model that is based on a superposition model for two-phase flow boiling of refrigerants in small tubes is presented. (author)

  15. Visualization of cross-sectional flow structure during condensation of steam in a slightly inclined horizontal tube

    Energy Technology Data Exchange (ETDEWEB)

    Puseya, Andree; Kim, H. [Kyung Hee University, Yongin (Korea, Republic of); Kwon, T. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    These flow characteristics called flow patterns still depend on a proper visualization technique in order to identify such local distribution. These proper distributions will have a dependence on the inclination of the tube as well, as it was demonstrated by Lips and Mayer. This work is focused on presenting an experimental investigation to visualize the cross sectional two-phase flow structure for condensation of steam in a horizontal tube and identify the liquid-gas interface using the axial-viewing technique. This innovative technique developed by Hewitt and more recently used in visualization works by Badie, permits the achievement to identify those systems in the area of interest by looking directly into the two-phase flow system during condensation of steam inside a pipe with technology such a high speed camera. An experimental work to visualize and locate the liquid-gas interface for steam condensation in horizontal tubes with slightly inclination was developed on this research The experimental results shows that the axial viewing technique works well with condensation phenomena and can be used for further developments in the field such as determination of liquid film geometry and calculation of void fraction.

  16. Technology of double casing tubes & a binary cycle system for hole cleaning for CBM multi-branch horizontal wells

    Directory of Open Access Journals (Sweden)

    Yong Yang

    2017-03-01

    Full Text Available At present, the aeration-assisted cutting-carrying technology is faced with complexities in the drilling of CBM multi-branch horizontal wells. For example, the aerating pressure is hardly maintained, and the borehole instability may happen. In view of these prominent problems, the technology of double casing tubes & a binary cycle system suitable for CBM multi-branch horizontal wells was developed according to the Venturi principle by means of parasitic tube insufflation which is used for well control simulation system. Then, a multiphase flow finite element model was established for the fluid-cutting particle system in this drilling condition. This technology was tested in field. Double-casing tubes cementing is adopted in this technology and a jet generator is installed at the bottom of the inner casing. In the process of drilling, the drilling fluid injected through double intermediate casing annulus is converted by the jet generator into a high-efficiency steering water jet, which, together with the water jet generated by the bit nozzle, increases the fluid returning rate in the inner annulus space. It is indicated from simulation results that the cutting-carrying effect is the best when the included angle between the nozzle of the jet generator and the vertical direction is 30°. Besides, the influential laws of cutting size, primary cycle volume, accessory cycle volume and drilling velocity on hole cleaning are figured out. It is concluded that this technology increases the flow rate of drilling fluid in annulus space, the returning rate of drilling fluid significantly and the cutting-carrying capacity. It is currently one of the effective hole cleaning technologies for CBM multi-branch horizontal wells where fresh water is taken as the drilling fluid.

  17. Refrigerant charge, pressure drop, and condensation heat transfer in flattened tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M J; Newell, T A; Chato, J C [University of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering; Infante Ferreira, C A [Delft University of Technology (Netherlands). Laboratory for Refrigeration and Indoor Climate Control

    2003-06-01

    Horizontal smooth and microfinned copper tubes with an approximate diameter of 9 mm were successively flattened in order to determine changes in flow field characteristics as a round tube is altered into a flattened tube profile. Refrigerants R134a and R410A were investigated over a mass flux range from 75 to 400 kg m{sup -2} s{sup -}2{sup 1} and a quality range from approximately 10-80%. For a given refrigerant mass flow rate, the results show that a significant reduction in refrigerant charge is possible. Pressure drop results show increases of pressure drop at a given mass flux and quality as a tube profile is flattened. Heat transfer results indicate enhancement of the condensation heat transfer coefficient as a tube is flattened. Flattened tubes with an 18{sup o} helix angle displayed the highest heat transfer coefficients. Smooth tubes and axial microfin tubes displayed similar levels of heat transfer enhancement. Heat transfer enhancement is dependent on the mass flux, quality and tube profile. (author)

  18. Counter-current flow in a vertical to horizontal tube with obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tye, P.; Matuszkiewicz, A.; Teyssedou, A. [Institut de Genie Nucleaire, Quebec (Canada)] [and others

    1995-09-01

    This paper presents experimental results on counter-current flow and flooding in an elbow between a vertical and a horizontal run. The experimental technique used allowed not only the flooding limit to be determined, but also the entire partial delivery region to be studied as well. The influence that various size orifices placed in the horizontal run have on both the delivered liquid flow rates and on the flooding limits is also examined. It is observed that both the flooding limits and the delivered liquid flow rates decrease with decreasing orifice size. Further, it is also observed that the mechanisms that govern the partial delivery of the liquid are significantly different when an orifice is present in the horizontal leg as compared to the case when no orifice is present.

  19. Characterization of two-phase flow regimes in horizontal tubes using 81mKr tracer experiments.

    Science.gov (United States)

    Oriol, Jean; Leclerc, Jean Pierre; Berne, Philippe; Gousseau, Georges; Jallut, Christian; Tochon, Patrice; Clement, Patrice

    2008-10-01

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. (81m)Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature.

  20. Characterization of two-phase flow regimes in horizontal tubes using 81mKr tracer experiments

    International Nuclear Information System (INIS)

    Oriol, Jean; Leclerc, Jean Pierre; Berne, Philippe; Gousseau, Georges; Jallut, Christian; Tochon, Patrice; Clement, Patrice

    2008-01-01

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. 81m Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature

  1. Characterization of two-phase flow regimes in horizontal tubes using {sup 81m}Kr tracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Oriol, Jean [LPAC, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Leclerc, Jean Pierre [Laboratoire des Sciences du Genie Chimique (LSGC), Nancy-Universite, CNRS, BP 20451, F-54001 Nancy (France)], E-mail: leclerc@ensic.inpl-nancy.fr; Berne, Philippe; Gousseau, Georges [L2T, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France); Jallut, Christian [Universite de Lyon, Universite Lyon 1, LAGEP, UMR CNRS 5007, ESCPE, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Tochon, Patrice; Clement, Patrice [GRETh, CEA Grenoble, 17, rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2008-10-15

    The diagnosis of heat exchangers on duty with respect to flow mal-distributions needs the development of non-intrusive inlet-outlet experimental techniques in order to perform an online fault diagnosis. Tracer experiments are an example of such techniques. They can be applied to mono-phase heat exchangers but also to multi-phase ones. In this case, the tracer experiments are more difficult to perform. In order to check for the capabilities of tracer experiments to be used for the flow mal-distribution diagnosis in the case of multi-phase heat exchangers, we present here a preliminary study on the simplest possible system: two-phase flows in a horizontal tube. {sup 81m}Kr is used as gas tracer and properly collimated NaI (TI) crystal scintillators as detectors. The specific shape of the tracer response allows two-phase flow regimes to be characterized. Signal analysis allows the estimation of the gas phase real average velocity and consequently of the liquid phase real average velocity as well as of the volumetric void fraction. These results are compared successfully to those obtained with liquid phase tracer experiments previously presented by Oriol et al. 2007. Characterization of the two-phase flow regimes and liquid dispersion in horizontal and vertical tubes using coloured tracer and no intrusive optical detector. Chem. Eng. Sci. 63(1), 24-34, as well as to those given by correlations from literature.

  2. The diffusion of microfinance.

    Science.gov (United States)

    Banerjee, Abhijit; Chandrasekhar, Arun G; Duflo, Esther; Jackson, Matthew O

    2013-07-26

    To study the impact of the choice of injection points in the diffusion of a new product in a society, we developed a model of word-of-mouth diffusion and then applied it to data on social networks and participation in a newly available microfinance loan program in 43 Indian villages. Our model allows us to distinguish information passing among neighbors from direct influence of neighbors' participation decisions, as well as information passing by participants versus nonparticipants. The model estimates suggest that participants are seven times as likely to pass information compared to informed nonparticipants, but information passed by nonparticipants still accounts for roughly one-third of eventual participation. An informed household is not more likely to participate if its informed friends participate. We then propose two new measures of how effective a given household would be as an injection point. We show that the centrality of the injection points according to these measures constitutes a strong and significant predictor of eventual village-level participation.

  3. An experimental study on two-phase pressure drop in small diameter horizontal, downward inclined and vertical tubes

    Directory of Open Access Journals (Sweden)

    Autee Arun

    2015-01-01

    Full Text Available An experimental study of two-phase pressure drop in small diameter tubes orientated horizontally, vertically and at two other downward inclinations of θ= 300 and θ = 600 is described in this paper. Acrylic transparent tubes of internal diameters 4.0, 6.0, and 8.0 mm with lengths of 400 mm were used as the test section. Air-water mixture was used as the working fluid. Two-phase pressure drop was measured and compared with the existing correlations. These correlations are commonly used for calculation of pressure drop in macro and mini-microchannels. It is observed that the existing correlations are inadequate in predicting the two-phase pressure drop in small diameter tubes. Based on the experimental data, a new correlation has been proposed for predicting the two-phase pressure drop. This correlation is developed by modification of Chisholm parameter C by incorporating different parameters. It was found that the proposed correlation predicted two-phase pressure drop at satisfactory level.

  4. An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

    Science.gov (United States)

    Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

    2015-05-01

    New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

  5. Measurement and analysis of the re-wetting front velocity during quench cooling of hot horizontal tubes

    Energy Technology Data Exchange (ETDEWEB)

    Takrouri, Kifah, E-mail: takroukj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Luxat, John, E-mail: luxatj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Hamed, Mohamed [Thermal Processing Laboratory (TPL), Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)

    2017-01-15

    Highlights: • Two phase flow & re-wetting front velocity were studied for quench of hot tubes. • The velocity decreased as temperature difference between tube and coolant decreased. • Increasing surface curvature was found to decrease the re-wetting front velocity. • Increasing tube thermal conductivity decreased the velocity. • Correlations were developed to predict the front velocity. - Abstract: When a liquid is put into contact with a hot dry surface, there exists a maximum temperature called the re-wetting temperature below which the liquid is in actual contact with the surface. Re-wetting occurs after destabilization of a vapor film that exists between the hot surface and the liquid. If re-wetting is established at a location on the hot surface, a wet patch appears at that location and starts to spread to cover and cool the entire surface. The outer edge of the wet patch is called the re-wetting front and can proceed only if the surface ahead of it cools down to the re-wetting temperature. Study of re-wetting heat transfer is very important in nuclear reactor safety for limiting the extent of core damage during the early stages of severe accidents after loss of coolant accidents LOCA and is essential for predicting the rate at which the coolant cools an overheated core. One of the important parameters in re-wetting cooling is the velocity at which the re-wetting front moves on the surface. In this study, experimental tests were carried out to investigate the re-wetting front velocity on hot horizontal cylindrical tubes being cooled by a vertical rectangular water multi-jet system. Effects of initial surface temperature in the range 400–740 °C, water subcooling in the range 15–80 °C and jet velocity in the range 0.17–1.43 m/s on the re-wetting front velocity were investigated. The two-phase flow behavior was observed by using a high-speed camera. The re-wetting front velocity was found to increase by increasing water subcooling, decreasing

  6. Two-phase heat transfer and pressure drop of LNG during saturated flow boiling in a horizontal tube

    Science.gov (United States)

    Chen, Dongsheng; Shi, Yumei

    2013-12-01

    Two-phase heat transfer and pressure drop of LNG (liquefied natural gas) have been measured in a horizontal smooth tube with an inner diameter of 8 mm. The experiments were conducted at inlet pressures from 0.3 to 0.7 MPa with a heat flux of 8-36 kW m-2, and mass flux of 49.2-201.8 kg m-2 s-1. The effect of vapor quality, inlet pressure, heat flux and mass flux on the heat transfer characteristic are discussed. The comparisons of the experimental data with the predicted value by existing correlations are analyzed. Zou et al. (2010) correlation shows the best accuracy with 24.1% RMS deviation among them. Moreover four frictional pressure drop methods are also chosen to compare with the experimental database.

  7. Microfinance & Strategy of Financial Inclusion in India

    OpenAIRE

    Gupta, Avnesh Kumar

    2012-01-01

    Abstract The main aim of this paper is to evaluate the role of microfinance in empowering the people and realization of government’s policy of financial inclusion in India. However, there are certain concerns about the efficiency of Microfinance Institutions in handling public money, their targeted growth, achievement of policy goals and demand and supply management of funds. Today, the Microfinance Institutions demand the government to empower them for mobilizing public savings. With incr...

  8. Demineralized water flow cancelling experiments with ice plug into high diameter horizontal tube (300 nominal diameter)

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Valeca, S.; Corbescu, B.; Puiu, D.; Panaitescu, V. N.

    2015-01-01

    The isolation with ice plug of a high diameter horizontal pipeline section is a specific technique for repairs activities/ replacements of components owning to thermo-hydraulic installations working with liquid agents. The application of such technique don.t assumes stopping of the entire system. The ice plugging inside of the pipeline assumes using of a special device and of an own specific technology for application. The paper contains a brief description of the experimental technological facilities used, followed by setting off the main moments in evolution of two experimental tests carried out on the test section with 300 mm nominal diameter for demineralized water and, finally, by a brief results analysis and some conclusions. The paper is dedicated to the specialists working in the research and technological engineering. (authors)

  9. Indoor Solar Thermal Energy Saving Time with Phase Change Material in a Horizontal Shell and Finned-Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    S. Paria

    2015-01-01

    Full Text Available An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF. The focus of this study was on the behavior of PCM for storage (charging or melting and removal (discharging or solidification, as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

  10. Indoor solar thermal energy saving time with phase change material in a horizontal shell and finned-tube heat exchanger.

    Science.gov (United States)

    Paria, S; Sarhan, A A D; Goodarzi, M S; Baradaran, S; Rahmanian, B; Yarmand, H; Alavi, M A; Kazi, S N; Metselaar, H S C

    2015-01-01

    An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM) in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF). The focus of this study was on the behavior of PCM for storage (charging or melting) and removal (discharging or solidification), as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

  11. Numerical simulation and experimental results of horizontal tube falling film generator working in a NH3-LiNO3 absorption refrigeration system

    International Nuclear Information System (INIS)

    Herrera, J.V.; Garcia-Valladares, O.; Gomez, V.H.; Best, R.

    2010-01-01

    This paper describes the work made at the Centro de Investigacion en Energia in the development of an absorption refrigeration system for cooling and refrigeration applications with a capacity of 10 kW. The single effect unit utilizes ammonia-lithium nitrate as working pair and it is air cooled. The generator is a falling film type with horizontal tubes where the heating oil flows inside the tube bank and the ammonia-lithium nitrate solution flows as a falling film on the tube outside, where it is heated and ammonia vapor is generated. The generator consists of tree columns and four rows per column of horizontal tubes. The system was tested at controlled conditions with heating oil obtained from an electric resistance heating loop. A numerical model of the horizontal falling film generator was developed that divided the system into three different thermal elements: the flow inside the tube, the heat conduction in the tube wall and the falling film solution flow. The mathematical model was tested and validated with experimental data and a study of the influence of the heat transfer coefficient for ammonia-lithium nitrate solution in the numerical model was carried out. A comparison between experimental and numerical data for the heat flux in the system and the temperature profiles in the oil and solution flows shown a good degree of correlation.

  12. Depressurization experiments on a plugged fibrous insulation in a horizontal pressure tube

    International Nuclear Information System (INIS)

    Lang, H.; Weise, H.J.; Ennen, P.

    1977-08-01

    Hot gas ducts for high-temperature reactors with a helium turbine are subject to additional operational loads not caused by the gas temperature. They include vibrations, caused by high gas velocities or by the sound fields emitted from the turbine, and stresses, originating from fast, short-time pressure changes. Such pressure changes occur as a rule if the generator coupled with the turbine has to be disconnected from the grid. In order to avoid no-load operation of the turbine a bypass between HP and LP side of the turbine is opened. As a consequence of this measure a sudden pressure drop occurs in the free flow cross-section causing differential pressures within the insulation. As the size of these differential pressures depends on the insulating material, the density of plugging, the kind of internals, and on the position and size of the depressurization borings, the pressure distributions in the insulation were measured on a test tube for the HP channel. (orig./RW) [de

  13. Microfinance als Geflecht von Anreizproblemen

    OpenAIRE

    Schmidt, Reinhard H.; Tschach, Ingo E.

    2001-01-01

    Während sich die Entwicklungsfinanzierung in Theorie und Praxis generell mit dem Finanzwesen in Entwicklungs- und Transformationsländern befasst, steht im Teilgebiet der Microfinance die Frage im Vordergrund, wie in diesen Ländern der Zugang ärmerer Bevölkerungsgruppen und speziell von Klein- und Kleinstunternehmer(innen), Kleinbauern und sonstigen wirtschaftlich Selbständigen aus eher niedrigen sozialen Schichten zu Kredit und anderen Finanzdiensleistungen verbessert werden kann. Obwohl es e...

  14. Introducing Micro-finance in Sweden

    DEFF Research Database (Denmark)

    Barinaga, Ester

    2013-01-01

    The case describes the first year of efforts to introduce microfinance as a tool to work with vulnerable groups in Sweden, more particularly ex-convicts, former drug-addicts and longterm unemployed women of immigrant background. The teaching objective is to discuss whether micro-finance can be seen...

  15. Microfinance and Information and Communication Technologies ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Microfinance and Information and Communication Technologies : HIVOS STAR Program (Eastern and Southern Africa) ... Studies. Management information systems for microfinance background to the workshop ... In this ROSSA bulletin: Meet Kathryn Toure, the new regional director of IDRC's sub-Saharan Africa office.

  16. Impact of Microfinance: A Critical Survey

    NARCIS (Netherlands)

    Lensink, B.W.; Hermes, N.

    2007-01-01

    It is unclear whether microfinance contributes to a reduction in poverty or is the most efficient method to reduce poverty without additional measures in areas such as education, health and infrastructure. The entry of commercial banks into microfinance may increase the competition for traditional

  17. La microfinanza in Europa (Microfinance in Europe

    Directory of Open Access Journals (Sweden)

    Fabrizio Botti

    2017-07-01

    Full Text Available So far, the lack of consistent and reliable data on microfinance in Europe prevented the conduct a comprehensive analysis of the performance of Microfinance institutions (MFIs, especially their capacity to meet policy expectation in terms of social objectives and financial sustainability in the long term. We constructed an original longitudinal dataset of 357 European MFIs observed between 2006 and 2015, based on raw data from the European Microfinance Network (EMN overview survey. We use this data to carry out the first in-depth analysis of trends in European microfinance and the interaction between social and financial performance during the period 2006-2013. It emerges that microfinance in Europe is a highly segmented and heterogeneous industry, both in terms of providers’ institutional characteristics and regional business models.JEL codes: G21; A13

  18. Bubble-assisted film evaporation correlation for saline water at sub-atmospheric pressures in horizontal-tube evaporator

    KAUST Repository

    Shahzad, Muhammad Wakil

    2013-01-01

    In falling film evaporators, the overall heat transfer coefficient is controlled by film thickness, velocity, liquid properties and the temperature differential across the film layer. This article presents the heat transfer behavior for evaporative film boiling on horizontal tubes, but working at low pressures of 0.93-3.60 kPa (corresponding solution saturation temperatures of 279-300 K) as well as seawater salinity of 15,000 to 90,000 mg/l or ppm. Owing to a dearth of literature on film-boiling at these conditions, the article is motivated by the importance of evaporative film boiling in the desalination processes such as the multi-effect distillation (MED) or multi-stage flashing (MSF): It is observed that in addition to the above-mentioned parameters, evaporative heat transfer of seawater is affected by the emergence of micro-bubbles within the thin film layer, particularly when the liquid saturation temperatures drop below 298 K (3.1 kPa). Such micro bubbles are generated near to the tube wall surfaces and they enhanced the heat transfer by two or more folds when compared with the predictions of conventional evaporative film boiling. The appearance of micro-bubbles is attributed to the rapid increase in the specific volume of vapor, i.e., dv/dT, at low saturation temperature conditions. A new correlation is thus proposed in this article and it shows good agreement to the measured data with an experimental uncertainty of 8% and regression RMSE of 3.5%. © 2012 Elsevier Ltd. All rights reserved.

  19. Experimental investigation on TBAB clathrate hydrate slurry flows in a horizontal tube: Forced convective heat transfer behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Wenji, Song [Guangzhou Institute of Energy Conversion, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Rui, Xiao; Chong, Huang; Shihui, He; Kaijun, Dong; Ziping, Feng [Guangzhou Institute of Energy Conversion, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China); Key Laboratory of Renewable Energy and Gas Hydrate, CAS, No. 2 Nengyuan Road, Tianhe District, Guangzhou 510640 (China)

    2009-11-15

    Tetra-n-butyl-ammonium bromide (TBAB) clathrate hydrate slurry (CHS) is one kind of secondary refrigerants, which is promising to be applied into air-conditioning or latent-heat transportation systems as a thermal storage or cold carrying medium for energy saving. It is a solid-liquid two phase mixture which is easy to produce and has high latent heat and good fluidity. In this paper, the heat transfer characteristics of TBAB slurry were investigated in a horizontal stainless steel tube under different solid mass fractions and flow velocities with constant heat flux. One velocity region of weakened heat transfer was found. Moreover, TBAB CHS was treated as a kind of Bingham fluids, and the influences of the solid particles, flow velocity and types of flow on the forced convective heat transfer coefficients of TBAB CHS were investigated. At last, criterial correlations of Nusselt number for laminar and turbulent flows in the form of power function were summarized, and the error with experimental results was within {+-}20%. (author)

  20. Measurement and correlation of frictional pressure drop of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hao; Ding, Guoliang; Jiang, Weiting; Hu, Haitao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, 381 Huaihaizhong Road, Shanghai 200020 (China)

    2009-11-15

    The objective of this paper is to investigate the effect of nanoparticle on the frictional pressure drop characteristics of refrigerant-based nanofluid flow boiling inside a horizontal smooth tube, and to present a correlation for predicting the frictional pressure drop of refrigerant-based nanofluid. R113 refrigerant and CuO nanoparticle were used for preparing refrigerant-based nanofluid. Experimental conditions include mass fluxes from 100 to 200 kg m{sup -2} s{sup -1}, heat fluxes from 3.08 to 6.16 kW m{sup -2}, inlet vapor qualities from 0.2 to 0.7, and mass fractions of nanoparticles from 0 to 0.5 wt%. The experimental results show that the frictional pressured drop of refrigerant-based nanofluid increases with the increase of the mass fraction of nanoparticles, and the maximum enhancement of frictional pressure drop is 20.8% under above conditions. A frictional pressure drop correlation for refrigerant-based nanofluid is proposed, and the predictions agree with 92% of the experimental data within the deviation of {+-}15%. (author)

  1. Theoretical Analysis of Effects of Wall Suction on Entropy Generation Rate in Laminar Condensate Layer on Horizontal Tube

    Directory of Open Access Journals (Sweden)

    Tong-Bou Chang

    2014-01-01

    Full Text Available The effects of wall suction on the entropy generation rate in a two-dimensional steady film condensation flow on a horizontal tube are investigated theoretically. In analyzing the liquid flow, the effects of both the gravitational force and the viscous force are taken into account. In addition, a film thickness reduction ratio, Sf, is introduced to evaluate the effect of wall suction on the thickness of the condensate layer. The analytical results show that, the entropy generation rate depends on the Jakob number Ja, the Rayleigh number Ra, the Brinkman number Br, the dimensionless temperature difference ψ, and the wall suction parameter Sw. In addition, it is shown that in the absence of wall suction, a closed-form correlation for the Nusselt number can be derived. Finally, it is shown that the dimensionless entropy generation due to heat transfer, NT, increases with an increasing suction parameter Sw, whereas the dimensionless entropy generation due to liquid film flow friction, NF, decreases.

  2. MARS-KS Code Assessment for Condensation Heat Transfer in Horizontal Tube with the Presence of Non-Condensable Gas using Purdue Experiment

    International Nuclear Information System (INIS)

    Jeon, Seong Su; Lee, Byung Chul; Park, Ju Yeop; Seul, Kwang Won

    2011-01-01

    In South Korea, advanced power reactor plus (APR+), as a Korean specific reactor, is currently under development for the export strategy. In order to raise competitiveness of the APR+ in the world market, it is necessary to develop the original technology for the improved technology, economics, and safety features. For this purpose, a passive auxiliary feedwater system (PAFS) was adopted as an improved safety design concept of APR+: and then there have been many efforts to develop the PAFS. According to PAFS design concept, PAFS can completely replace the auxiliary feedwater system. When the design basis accident, in which feedwater is unavailable, occurs, the PAFS can remove the residual heat in the core and then prevent the core damage. In the PAFS with the horizontal type heat exchanger, two-phase natural circulation, condensation heat transfer in tube, boiling heat transfer in pool, natural convection in pool, etc. are considered as very important thermalhydraulic phenomena (see Fig. 1). Compared with the vertical heat exchanger from these phenomena, the major difference of the horizontal heat exchanger is the condensation heat transfer phenomena in the tube side. There have been many efforts to understand the condensation heat transfer with in the presence of NC gas in tube but most researches focused on the condensation heat transfer in vertical tube. Therefore the details of the condensation heat transfer in the presence of NC gas in horizontal condenser tubes are not well understood. In order to develop the safety evaluation system for APR+ PAFS, it is required to evaluate the capability and applicability of the MARS-KS code for modeling the condensation heat transfer in the horizontal tube with NC gas because many heat transfer correlations in MARS-KS are known to have much uncertainty. In particular, there is no reliable model for the condensation phenomena in horizontal tube with NC gas. In order to assess the MARS-KS code results and identify the

  3. Microfinance and female empowerment : Do institutions matter?

    NARCIS (Netherlands)

    Haile, Hirut Bekele; Bock, Bettina; Folmer, Henk

    2012-01-01

    Microfinance programmes increasingly target poor women in developing countries with the expectation that, besides poverty reduction, having access to microcredit advances their empowerment. However, research provides conflicting evidence and shows that empowerment may not, or may only be partially

  4. Microfinance and female empowerment: Do institutions matter?

    NARCIS (Netherlands)

    Haile Hirut, Bekele; Folmer, H.; Bock, B.B.

    2012-01-01

    Microfinance programmes increasingly target poor women in developing countries with the expectation that, besides poverty reduction, having access to microcredit advances their empowerment. However, research provides conflicting evidence and shows that empowerment may not, or may only be partially

  5. Microfinance in a Developed Welfare State

    DEFF Research Database (Denmark)

    Barinaga, Ester

    2014-01-01

    in Sweden. Savings banks and nonprofit organisations collaborated in the introduction of microfinance as microcredit for micro-enterprise. The paper argues that the rationalities behind actors' participation in microfinance differed, with banks adopting a market rationality and nonprofits mainly...... a rationality of community empowerment. In line with a governmentality approach, the paper argues that the neoliberal market rationality dominating microcredit for micro-enterprise colonises the space of the communitarian aspect by turning the social into the personal. The paper's qualitative approach...

  6. Has Microfinance Lost its Moral Compass?

    OpenAIRE

    David Hulme; Mathilde Maitrot

    2014-01-01

    Abstract This paper argues that microfinance in South Asia, like mainstream finance in North America and Europe, "has lost its moral compass". Our particular concern is with microloans to vulnerable clients. Microfinance institutions (MFIs) have increasingly focussed on financial performance and have neglected their declared social mission of poverty reduction and empowerment. Loans officers in the field are under enormous pressure to achieve individual financial targets and now routinely mis...

  7. Influence of oil on flow condensation heat transfer of R410A inside 4.18 mm and 1.6 mm inner diameter horizontal smooth tubes

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu.; Peng, Hao [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Gao, Yifeng [International Copper Association Shanghai Office, Shanghai 200020 (China); Deng, Bin [Institute of Heat Transfer Technology, Golden Dragon Precise Copper Tube Group Inc., Shanghai 200135 (China)

    2010-01-15

    The influence of oil on condensation heat transfer of R410A inside 4.18 mm and 1.6 mm inner diameter horizontal smooth tubes is investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer, and the deterioration effect becomes obvious with the increase of oil concentration. At oil concentration of 5%, the heat transfer coefficient decreases by maximum 24.9% and 28.5% for 4.18 mm and 1.6 mm tubes, respectively. A new correlation for heat transfer coefficients of R410A-oil mixture flow condensation inside smooth tubes is proposed, which agrees with all the experimental data within a deviation of -30% {proportional_to} +20%. (author)

  8. 139 THE IMPACT OF MICROFINANCE BANK CREDIT ON ...

    African Journals Online (AJOL)

    Key words: Microfinance bank, Economic development, Deposit mobilisation, ... a means of reaching those that were not served by the conventional big banks to ..... J (2000) Microfinance Handbook: An Institutional and Financial Perspective.

  9. Microfinance around the world – regional SWOT analysis

    OpenAIRE

    Harmincova, Zuzana; Janda, Karel

    2014-01-01

    The paper focuses on comparison of the functioning of microfinance in various developing regions of the world, as well as on the analysis of the overall functioning, effectiveness, strengths and weaknesses, potential threats and opportunities in the microfinance markets. The conclusion offers several possibilities and insights on how microfinance could be more efficient in financial terms. The paper also presents a brief evaluation of the benefits of microfinance and based on its findings pro...

  10. Effects of Tube Diameter and Tubeside Fin Geometry on the Heat Transfer Performance of Air-Cooled Condensers

    Science.gov (United States)

    Wang, H. S.; Honda, Hiroshi

    A theoretical study has been made on the effects of tube diameter and tubeside fin geometry on the heat transfer performance of air-cooled condensers. Extensive numerical calculations of overall heat transfer from refrigerant R410A flowing inside a horizontal microfin tube to ambient air were conducted for a typical operating condition of the air-cooled condenser. The tubeside heat transfer coefficient was calculated by applying a modified stratified flow model developed by Wang et al.8). The numerical results show that the effects of tube diameter, fin height, fin number and helix angle of groove are significant, whereas those of the width of flat portion at the fin tip, the radius of round corner at the fin tip and the fin half tip angle are small.

  11. Thermal design of horizontal tube boilers. Numerical and experimental investigation; Modelisation thermique de bouilleurs a tubes horizontaux. Etude numerique et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R.

    1999-11-26

    This work concerns the thermal design of kettle reboilers. Current methods are highly inaccurate, regarded to the correlations for external heat transfer coefficient at one tube scale, as well as to two-phase flow modelling at boiler scale. The aim of this work is to improve these thermal design methods. It contains an experimental investigation with typical operating conditions of such equipment: an hydrocarbon (n-pentane) with low mass flux. This investigation has lead to characterize the local flow pattern through void fraction measurements and, from this, to develop correlations for void fraction, pressure drop and heat transfer coefficient. The approach is original, since the developed correlations are based on the liquid velocity at minimum cross section area between tubes, as variable characterizing the hydrodynamic effects on pressure drop and heat transfer coefficient. These correlations are shown to give much better results than those suggested up to now in the literature, which are empirical transpositions from methods developed for inside tube flows. Furthermore, the numerical code MC3D has been applied using the correlations developed in this work, leading to a modeling of the two-phase flow in the boiler, which is a significant progress compared to current simplified methods. (author)

  12. Factors influencing Sudanese microfinance intention to adopt mobile banking

    Directory of Open Access Journals (Sweden)

    Anwar Ammar

    2016-12-01

    Full Text Available Access to financial service has become a key phenomenon for economic development and poverty alleviation .Microfinance is one way of fighting poverty in Sudan, where most citizens are in need of it. However, despite the initial results showing a positive impact of microfinance on the livelihood of low-income people in Sudan, around 8 million of the Sudanese poor people are excluded from microfinance services. One potential remedy for the limited outreach of microfinance in Sudan may lie within enhancing the capacity of microfinance services providers (MFPs in the utilization of modern technology. Recent innovation in providing financial services in a convenient and efficient way is the use of mobile banking (m-banking technology in microfinance. M-banking promises to increase the efficiency and outreach of microfinance services in developing countries. This paper tries to examine the factors that influence the adoption of m-banking by microfinance sector in Sudan. In this respect, hypotheses were developed guided by Unified Theory of Acceptance and Use of Technology (UTAUT and Technology-organization-Environment (TOE models. Primary data were collected from MFPs and microfinance customers in Sudan using questionnaires and interviews. The study contributes to knowledge in terms of methods used by extending aforementioned theories through adding new variables to both models by putting both models in one study to fill the gaps in past studies; via examination of the demand (customers and supply (institutions through modifying them to include new variables related to m-banking in microfinance.

  13. Surface Tension of Supercooled Water: Inflection Point-Free Course down to 250 K Confirmed Using a Horizontal Capillary Tube

    Czech Academy of Sciences Publication Activity Database

    Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

    2017-01-01

    Roč. 62, č. 11 (2017), s. 3823-3832 ISSN 0021-9568 R&D Projects: GA ČR(CZ) GJ15-07129Y Institutional support: RVO:61388998 Keywords : horizontal technique * metastable liquid * supercooled Subject RIV: BJ - Thermodynamics OBOR OECD: Thermodynamics Impact factor: 2.323, year: 2016 http://pubs.acs.org/doi/pdf/10.1021/acs.jced.7b00519

  14. Book Review Microfinance: Perils and Prospects

    African Journals Online (AJOL)

    African Review of Economics and Finance, Vol 4, No. 2, June ... This book explores the perils and prospects of microfinance by looking at the issue ... qualitative data, and a list of references that could be useful to readers who want to learn ...

  15. Essays on microfinance in Latin America

    NARCIS (Netherlands)

    Servin Juarez, R.

    2012-01-01

    In the early 1970s, microfinance came to public attention as a promising tool to reduce poverty. However, some people began to claim that microcredit is unsuitable for sustainable development. Nevertheless, the lack of scientific support for both viewpoints has created a need for

  16. Housing policies in developing countries: Microfinance

    NARCIS (Netherlands)

    Smets, P.G.S.M.; Smith, S.J.; Elsinga, M.; O’Mahony, L.H.; Ong, S.E.; Wachter, S.; Wood, G.

    2012-01-01

    Shelter is a basic human need for which financial means are required. Poorer sections of society face difficulties in accessing and coping with conventional mortgage finance and are better assisted with housing microfinance. This enables the poor, especially in 'developing' countries to build their

  17. Outreach and Efficiency of Microfinance Institutions

    NARCIS (Netherlands)

    Hermes, N.; Lensink, B.W.; Meesters, A.

    2011-01-01

    This paper uses stochastic frontier analysis to examine whether there is a trade-off between outreach to the poor and efficiency of microfinance institutions (MFIs). We find convincing evidence that outreach is negatively related to efficiency of MFIs. More specifically, we find that MFIs that have

  18. Managing growth of microfinance institutions (MFIs): Balancing ...

    African Journals Online (AJOL)

    The overriding objective of MFIs in Ethiopia is to provide a broad range of microfinance services to large numbers of poor households. This is realized by developing capable and sustainable MFIs. A large number of MFIs have achieved significant progress in terms of both outreach and sustainability. As of June 2005, the ...

  19. Numerical analysis on the condensation heat transfer and pressure drop characteristics of the horizontal tubes of modular shell and tube-bundle heat exchanger

    International Nuclear Information System (INIS)

    Ko, Seung Hwan; Park, Hyung Gyu; Kim, Charn Jung; Park, Byung Kyu

    2001-01-01

    A numerical analysis of the heat and mass transfer and pressure drop characteristics in modular shell and tube bundle heat exchanger was carried out. Finite concept method based on FVM and κ-ε turbulent model were used for this analysis. Condensation heat transfer enhanced total heat transfer rate 4∼8% higher than that of dry heat exchanger. With increasing humid air inlet velocity, temperature and relative humidity, and with decreasing heat exchanger aspect ratio and cooling water velocity, total heat and mass transfer rate could be increased. Cooling water inlet velocity had little effect on total heat transfer

  20. Performance Analysis of Microfinance Institutions of India

    Directory of Open Access Journals (Sweden)

    Muhammad Azhar Ikram Ahmad

    2014-12-01

    Full Text Available This is a study of Microfinance Institutions-MFIs of India. It includes analysis of MFIs of India. This study includes analysis of performance of microfinance institutions with reference to both financial and non-financial ways. Performance of microfinance institutions is measured using four parameters, which are sustainability/profitability, outreach, operational and financial efficiency. Data is taken of 99 Microfinance Institutions of India from the Microfinance Information Exchange for a period of 11 years. Variables of this study are both in absolute and relative terms. The endogenous variables are Return on Assets and Return on Equity for sustainability, Number of Borrowers per Staff Member for operational efficiency, Cost per Borrower for financial efficiency, and Number of Active Borrowers for outreach. Panel data analysis is done after checking the assumptions of the model. Hausman Test is applied to find out the suitability of Fixed or Random Effect Model. Both random and fixed effect were found suitable for application. In addition to this descriptive analysis of the variables is also done. The results show that most of the variables used in the study are significant in outreach model; other than rank, financial revenue to assets ratio, portfolio at risk, deposits, and capital to assets ratio all other variables are significant in case of sustainability using ROA model and same variables are found insignificant in ROE model except financial expense to assets ratio; in financial efficiency model both significant and insignificant variables are found; and in case of operational efficiency all variables are found significant.

  1. Simulation of steam condensation in the presence of noncondensable gases in horizontal condenser tubes using RELAP5 for advanced nuclear reactors

    International Nuclear Information System (INIS)

    Macedo, Luiz Alberto; Torres, Walmir Maximo

    2009-01-01

    Horizontal heat exchangers are used in advanced light water nuclear reactors in their passive cooling systems, such as residual heat removal (RHRS) and passive containment cooling system (PCCS). Condensation studies of steam and noncondensable gases mixtures in these heat exchangers are very important due to the phenomena multidimensional nature and the condensate stratification effects. This work presents a comparison between simulation results and experimental data in steady state conditions for some inlet pressure, steam and noncondensable gases (air) inlet mass fractions. The test section is three meters long and consists of two concentric tubes containing pressure, temperature and flow rate sensors. The internal tube, called condenser, contains steam-air mixture flow and external tube is a counter current cooler with water flow rate at low temperature. This test section was modeled and simulations were performed with RELAP5 code. Experimental tests were carried out for 200 to 400 kPa inlet pressure and 5, 10, 15 and 20% of inlet air mass fractions. Comparisons between experimental data and simulation results are presented for 200 and 400 kPa pressure conditions and showed good agreement. However, for 400 kPa inlet steam pressure and inlet air mass fractions above 5%, the simulated temperatures are lower than the experimental data at the final third from the inlet condenser tube, indicating a code overestimation of heat transfer coefficient. New correlations for heat transfer coefficient in these steam-air conditions must be theoretical and experimentally studied and implemented in RELAP5 code for better representing the condensation phenomena. (author)

  2. Experimental investigation of quench and re-wetting temperatures of hot horizontal tubes well above the limiting temperature for solid–liquid contact

    Energy Technology Data Exchange (ETDEWEB)

    Takrouri, Kifah, E-mail: takroukj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Luxat, John, E-mail: luxatj@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Hamed, Mohamed [Thermal Processing Laboratory (TPL), Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)

    2017-01-15

    Highlights: • Quench and re-wetting temperatures were measured upon jet quenching of hot cylindrical tubes. • Correlations have been developed and provided good fit of data. • Quench and re-wetting temperatures were found to greatly depend on water subcooling. • Stagnation point showed higher quench and re-wetting temperatures than other locations. • Quench temperature decreased by increasing surface curvature and tube conductivity. • Re-wetting temperature is a weak function of both variables. - Abstract: Quench cooling of a hot dry surface involves the rapid decrease in surface temperature resulting from bringing the hot surface into sudden contact with a coolant at a lower temperature. Quench temperature is the onset of the rapid decrease in surface temperature and corresponds to the onset of destabilization of a vapor film that exists between the hot surface and the coolant. Situations involving quench cooling are encountered in a number of postulated accidents in Canada Deuterium Uranium CANDU reactors, such as the quench of a hot calandria tube in certain Loss of Coolant Accidents LOCA. If the calandria tube temperature is not reduced by initiation of quench heat transfer, then this may lead to subsequent fuel channel failure and for this accident knowledge of quench heat transfer characteristics is of great importance. In this study, a Water Quench Facility WQF has been designed and built at the Thermal Processing Laboratory TPL at McMaster University and a series of experimental tests were carried out to investigate the quench of hot horizontal tubes using a vertical rectangular water multi-jet system. The tubes were heated to a temperature between 380 and 780 °C then cooled to the jet temperature. The temperature variation with time in tube circumferential and axial directions was measured. The two-phase flow behavior and the propagation of the re-wetting front around and along the tubes were simultaneously observed using a high-speed camera

  3. Flexible Products in Microfinance: Overcoming the Demand-Supply Mismatch

    OpenAIRE

    Labie, Marc; Laureti, Carolina; Szafarz, Ariane

    2013-01-01

    The success of microfinance rests upon product simplicity, standardization, and the capacity to stimulate client discipline. However, poor people desperately need flexible financial products to improve their day-to-day money management and cope with shocks. This paper discusses how microfinance institutions could design flexible products efficiently. First, we clarify the concept of financial flexibility. Second, based on literature in microfinance, banking, and behavioral economics, we summa...

  4. Experimental study on heat transfer with condensation of vapors of pure nitrogen tetroxide with nitrogen oxide additions on a bundle of horizontal tubes

    International Nuclear Information System (INIS)

    Batishcheva, T.M.; Derov, B.T.; Kolykhan, L.I.; Pulyaev, V.F.

    1977-01-01

    The results of an experimental investigation of heat transfer during condensation of pure N 2 O 4 vapours and with NO admixtures on the outside surface of a bundle of horizontal tubes are considered. The tests with pure N 2 O 4 have been performed at pressures between 0.3-1.0 MPa in the range of thermal loads 22-121 kW/m 2 , temperature heads of 5-33 grades with complete condensation and evaporation. The content of admixtures boiling at high temperatures do not exceed 0.8%. A concentration of noncondensing nitrogen oxide in a gas phase have changed in the range of 3-27%. It is shown, that a concentration of noncondensible NO doesn't result in a considerable decrease of the heat transfer intensity as well as in the case of condensation of vapour-liquid mixtures. The generalized criterion relations are presented

  5. Islamic vs Conventional Microfinance Institutions: Performance analysis in MENA countries

    Directory of Open Access Journals (Sweden)

    Ines Ben Abdelkader

    2013-07-01

    Full Text Available Microfinance has been identified as an important policy instrument that allows greater financial and social independence for women and poor by facilitating access to financial services for the poorest and destitute. Microfinance institutions (MFIs have mostly a high concentration of women beneficiaries and aim at alleviation of poverty in all its forms. Accordingly, the principal purpose of microfinance institutions is to be social performing by reducing poverty. However, they have to reconcile this objective with financial performance by trying to be profitable and sustainable. On other side, Islamic Microfinance has progressively growing in the world, particularly in poor countries, as credible alternative which allows poor populations to have access to basic financial services at low cost. The integration of Islamic finance concepts to microfinance was one of the valuable reasons in attracting poor to get advantage of these services. Whereas the complexity of these methods in microfinance and lack of transparency in profit distribution, there are some challenges about their efficiency. It is therefore of utmost interest to consider if the financial performance of Islamic microfinance institutions will be negatively correlated with the depth of outreach. The aim of this paper is to examine the performance of Islamic microfinance institutions in comparison with conventional institutions. This study focuses analysis on the MENA region, where a large proportion of the poor are practicing Muslims and are thus unable to take advantage of traditional microfinance contracts which are incompatible with Sharia’. Using a non parametric data envelopment analysis (DEA to estimate the efficiency of the microfinance institutions, our study provides the empirical evidence from Islamic and conventional microfinance institutions in MENA region.

  6. Game Theoretical Approach to Supply Chain Microfinance

    OpenAIRE

    Sim , Jaehun; Prabhu , Vittaldas ,

    2013-01-01

    Part 1: Sustainable Production; International audience; This paper considers a supply chain microfinance model in which a manufacturer acts as a lender and a raw material supplier as a borrower. Using a game theoretical analysis, the study investigates how investment levels, raw material prices, and profit margins are influenced by loan interest rates under two types of decentralized channel policies: manufacturer Stackelberg and vertical Nash game. In addition, the study shows how the profit...

  7. The impact of microfinance institution in economic growth of a ...

    African Journals Online (AJOL)

    The findings of the study show that microfinance loans have a significant positive impact on the short run economic performance in Nigeria. Microfinance loans enhanced consumption per capita in short run with an impressive coefficient, although these banks' loans do not have a significant impact on economic growth in ...

  8. Microfinance and rural development: a long-term perspective

    NARCIS (Netherlands)

    Moll, H.A.J.

    2006-01-01

    The long-term perspective on microfinance starts with a discussion of three central issues: first, views and policies, with two opposing views: "credit for target group" and "pushing the financial frontier"; second, the performance of microfinance institutions measured via two objectives: outreach

  9. Do microfinance institutions benefit from integrating financial and nonfinancial services?

    NARCIS (Netherlands)

    Lensink, Robert; Mersland, Roy; Vu, Nhung Thi Hong; Zamore, Stephen

    2018-01-01

    This article examines the impact of microfinance ‘plus’ (i.e. coordinated combination of financial and nonfinancial services) on the performance of microfinance institutions (MFIs). Using a global data set of MFIs in 77 countries, we find that the provision of nonfinancial services does not harm nor

  10. Practice What You Preach: Microfinance Business Models and Operational Efficiency

    NARCIS (Netherlands)

    Bos, J.W.B.; Millone, M.M.

    The microfinance sector has room for pure for-profit microfinance institutions (MFIs), non-profit organizations, and “social” for-profit firms that aim to pursue a double bottom line. Depending on their business model, these institutions target different types of borrowers, change the size of their

  11. Practice what you preach: Microfinance business models and operational efficiency

    NARCIS (Netherlands)

    Bos, J.W.B.; Millone, M.M.

    2013-01-01

    The microfinance sector is an example of a sector in which firms with different business models coexist. Next to pure for-profit microfinance institutions (MFIs), the sector has room for non-profit organizations, and includes 'social' for-profit firms that aim to maximize a double bot- tom line and

  12. Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

    Energy Technology Data Exchange (ETDEWEB)

    Zuercher, O.; Favrat, D.; Thome, J. R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d` energetique industrielle, Lausanne (Switzerland)

    1996-11-15

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

  13. Can Microfinance Reach the Poorest: Evidence from a Community-Managed Microfinance Intervention

    DEFF Research Database (Denmark)

    Lonborg, J. H.; Rasmussen, O. D.

    2014-01-01

    Reaching the poorest is an important objective in many development interventions, and microfinance is no exception. We review performance indicators for effectiveness of targeting described in the literature and suggest a new metric in order to account for extent and severity of poverty as well...

  14. Experimental study on heat transfer enhancement of laminar ferrofluid flow in horizontal tube partially filled porous media under fixed parallel magnet bars

    Energy Technology Data Exchange (ETDEWEB)

    Sheikhnejad, Yahya; Hosseini, Reza, E-mail: hoseinir@aut.ac.ir; Saffar Avval, Majid

    2017-02-15

    In this study, steady state laminar ferroconvection through circular horizontal tube partially filled with porous media under constant heat flux is experimentally investigated. Transverse magnetic fields were applied on ferrofluid flow by two fixed parallel magnet bar positioned on a certain distance from beginning of the test section. The results show promising notable enhancement in heat transfer as a consequence of partially filled porous media and magnetic field, up to 2.2 and 1.4 fold enhancement were observed in heat transfer coefficient respectively. It was found that presence of both porous media and magnetic field simultaneously can highly improve heat transfer up to 2.4 fold. Porous media of course plays a major role in this configuration. Virtually, application of Magnetic field and porous media also insert higher pressure loss along the pipe which again porous media contribution is higher that magnetic field. - Highlights: • Porous media can improve the coefficient of heat transfer up to 2.2 fold. • Both porous media and Nano particles have undesired pressure drop effect. • Application of both porous media and magnetic field in ferrofluid flow will result in significant enhancement in heat transfer up to 2.4 fold. • Magnet bar effect is mainly restricted to approximately one fourth of the test section. • Diluted Ferrofluids 2%, results in over 1.4 fold enhancement in heat transfer coefficient.

  15. Factors Influencing Poverty Alleviation amongst Microfinance Adopting Households in Zambia

    Directory of Open Access Journals (Sweden)

    Mavhungu Abel Mafukata

    2016-01-01

    Full Text Available The main objective of this paper is to investigate the factors having the most influence on the alleviation of poverty amongst the households adopting microfinance in Zambia. Ninety nine (n=99 respondents were randomly and purposively selected from amongst 340 microfinance adopters of the so-called Micro Bankers Trust programme operating a microfinance business in the Makululu Compound of Kabwe, Zambia. Socio-demographic primary data were collected through face-to-face interviews based on a semi-structured questionnaire instrument. The data were entered into an excel spreadsheet for analysis. The descriptive data were thereafter exported and fitted to an empirical model. The descriptive results revealed that the majority of the respondents were married, unemployed, fairly educated younger women from larger-sized poor households who drew their household income mainly from microfinance activities. The majority of the respondents thought microfinance had improved their well-being in some crucial areas. The results of the empirical model found that some respondents were indeed alleviated from poverty through microfinance. Conclusion drawn in this paper is that microfinance does alleviate poverty of the poor.

  16. Islamic Microfinance Branchless Banking Model in Indonesia

    Directory of Open Access Journals (Sweden)

    Bedjo Santoso

    2017-01-01

    Full Text Available ICT has been recently developed into a digital sustainable collaborative networking (DCN platform, and it is expected to be capable of demonstrating the building of social and economic welfare, particularly in crafting innovations to facilitate marginal society.This research attempts to develop an innovative platform of an empirical ICT application a branchless banking form based on ICT Model. The application of Branchless banking model is expected to address the poverty problem which is significantly high in Indonesia. Indonesia is known for it’s heterogeneous values in terms of its areas, ethics, traditions, customs, communities, and local wisdom. The newly introduced application of a mobile payment system is parallel to the vision, and mission upheld by the government. Currently, most literature and practices are just partial. The community model based on Islamic microfinance and Cooperatives is neglected. Therefore, this research aims to design branchless banking in terms of financial inclusion involving Islamic microfinance and Cooperatives. Furthermore, this paper also attempts to test to what extent the proposed model is viable in the current system. This study employs a qualitative approach by conducting an interview with the stakeholders and a deductive method is used to explore and design the proposed model. The finding exhibit that branchless banking based on an Islamic microfinance and a Cooperative model is more flexible and easily acceptable while crafting a deal with Indonesian. In addition, the proposed model is viable in the current system. By implementing this model, the economy can be strengthened toward national unity and a welfare state.

  17. The exposure of microfinance institutions to financial risk

    Directory of Open Access Journals (Sweden)

    Thomas Gietzen

    2017-12-01

    Full Text Available This study examines the exposure of microfinance institutions to liquidity-, interest rate and foreign exchange (FX risk. Using manually collected data from microfinance institutions’ financial reporting, I find that the microfinance sector faces minimal liquidity risk, high interest rate risk and a lower than commonly assumed exposure to FX risk. Linking risk exposure to institutional characteristics, the data shows that legal status and regional affiliation are correlated with risk exposure while regulatory quality is not. Results suggest that the development community may not expect large benefits from expanding the plethora of current measures taken to mitigate liquidity or FX risk.

  18. AN EXPERIMENTAL STUDY FOR HEAT TRANSFER ENHANCEMENT BY LAMINAR FORCED CONVECTION FROM HORIZONTAL AND INCLINED TUBE HEATED WITH CONSTANT HEAT FLUX, USING TWO TYPES OF POROUS MEDIA

    Directory of Open Access Journals (Sweden)

    Thamir K. Jassem

    2015-02-01

    Full Text Available An experimental forced laminar study was presented in this research for an air flowing through a circular channel for different angles ( ,30o,45o,60o, the channel was heated at constant heat flux , the channel also was packed with steel and glass spheres respectively . The tests were done for three values of Peclets number (2111.71,3945.42,4575.47 with changing the heat flux for each case and five times for each number.The results showed that the dimensionless temperature distribution  will decrease with increasing the dimensionless channel length for all cases with changing Peclet number, heat flux and inclination angles, and its lowest value will be for glass spheres at highest flux, while at lower flux for , and the decreasing in dimensionless temperature was closed for both types of packed at other inclination angles.The study declared that the local Nusselt number decreases with increasing the dimensionless length of the channel for both packeds and for different applied heat flux, also through this study it was declared that the average Nusselt increases as Peclet number increases for both packed. Its value for the glass spheres is greater than the steel spheres with percentage (98.3% at small Peclet, and percentage (97.2% at large Peclet number for the horizontal tube, and (98.3% at small Peclet number and (97.8% at large Peclet number at  .Through this study its was found that average Nusselt number increases along the channel as the heat flux increases, because the bulk temperature will increase as the flow proceeds toward the end of the channel , so the heat transfer coefficient will increase.  It was declared from this study that in the case of the steel packed the heat transfer will occur mainly by conduction, while in the case of glass packed the heat transfer will occur mainly by laminar forced convection, where the lowest Nusselt number (Nu=3.8 was found when the pipe is horizontal and lowest heat flux and lowest Peclet number.  

  19. A comparison of R-22, R-134a, R-410a, and R-407c condensation performance in smooth and enhanced tubes: Part 2, Pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Eckels, S J; Tesene, B A

    1999-07-01

    This paper reports pressure drops during condensation for R-22, R-134a, R-410a, and R-407c in three enhanced tubes and one smooth tube. The test tubes were a 3/8 inch outer diameter smooth tube, a 3/8 inch outer diameter microfin tube, a 5/16 inch outer diameter microfin tube, and a 5/8 inch outer diameter microfin tube. Pressure drops are reported at four mass fluxes, at two saturation temperatures, and over a range of average qualities in the test tubes. The pressure drops for R-410a were approximately 40% lower than those of R-22 in both tubes. R-407c had 10% to 20% lower pressure drops than R-22, while 134-a had slightly larger pressure drops than R-22. The microfin tube pressure drops were, on average, 40% to 80% higher than those for the smooth tube for all refrigerants. The pressure drop penalty of the microfin tube was shown to decrease with increased quality.

  20. Dynamic Incentives in Microfinance Group Lending

    Directory of Open Access Journals (Sweden)

    Naveen Kumar K

    2012-04-01

    Full Text Available One of the most essential tools of poverty reduction would be the viable expansion of institutional credit facilities to large sections of the people who neither have adequate collateral nor credit history to secure a loan. In this backdrop, social collateral is popularized through the group lending programs to address the credit market problems. Microfinance through group lending is acting as a screening device; the joint liability mechanism creates incentives for internal monitoring. Hence, it has received a lot of attention from policy makers as well as academicians. It is playing an important role in delivering financial services to the “socially and economically excluded” poor, in general, and women, in particular. The group lending works with various dynamic incentives. One such kind is principle of progressive lending and it plays a vital role in sustaining the groups for the persistent delivery of microfinance services to its members. In progressive lending, a typical borrower receives very small amounts at first, which increases with good repayment conduct or it links new, larger loans to past repayment. This article explores possible theoretical and empirical relationship between progressive lending and its determinants in group lending approach. The primary survey was conducted in 10 villages covering 106 self-help groups and 318 members in Karnataka, India. The empirical results show the progressive lending amount rising up to 698% of the initial loan of the self-help groups.

  1. Efficiency of Microfinance Institutions in Sub – Saharan Africa: A ...

    African Journals Online (AJOL)

    2016-10-02

    Oct 2, 2016 ... major constraint on the development of the microfinance industry (Helms, 2006). The efficient ..... It also enables statistical tests of hypothesis to be performed. Hence, the ...... Cost efficiency in Australian Local Government: A.

  2. Business Management Models of Microfinance Institutions (MFIs) in Africa:

    NARCIS (Netherlands)

    Pashkova, Nadya; Trujillo-Barrera, Andres; Apostolakis, George; Dijk, Van Gert; Drakos, Periklis D.; Baourakis, George

    2016-01-01

    In this study, the authors analyse the socioeconomic, political and geographic conditions that are conducive of cooperative microfinance initiatives in comparison with other organizational forms in Africa. They distinguish three types of institutions (MFIs) and business models: cooperatives/credit

  3. Impact of Debt Capital on Outreach and Efficiency Of Microfinance ...

    African Journals Online (AJOL)

    Impact of Debt Capital on Outreach and Efficiency Of Microfinance ... donation or government grants should be sustained in a long term to enable MFIs reach the poor who cannot afford high interest rates charged by debt financed MFIs.

  4. The Impact of Microfinance on Household Welfare in Botswana ...

    African Journals Online (AJOL)

    of poverty in Botswana include lack of opportunities for self-employment to generate income and constrained ... et al, 2013). Other scholars observed that microfinance has no significant impact on household ... including political leadership) ...

  5. Do leadership styles matter in microfinance performance? Empirical ...

    African Journals Online (AJOL)

    ... been concerned with building vibrant institutions within the financial sector. In this direction, managers of these institutions need to bring their leadership styles to ... style should be encouraged for the management of microfinance institutions.

  6. Towards the establishment of cash waqf microfinance fund for refugees

    Directory of Open Access Journals (Sweden)

    Omar Ahmad Kachkar

    2017-07-01

    Full Text Available Purpose - This paper aims to propose cash waqf (endowment to develop a conceptual model that can be utilised to extend microfinance for refugees. Design/methodology/approach - Qualitative method is used in this research. An extensive review of the literature has been conducted. Latest literature on refugees, microfinance has been critically examined beside the current cash waqf models. Findings - Empirical studies have shown that many refugees are equipped with marketable skills and talents that can be utilised to improve their socio-economic situations. The proposed model – cash waqf refugee microfinance fund (CWRMF – is structured to extend microfinance to potential refugee micro entrepreneurs. To address the lack of collateral, which is a requirement to gain any microfinance, CWRMF has been incorporated with a takaful unit (cooperation by which refugees may guarantee each other. Additionally, the model has also been structured to address the challenge of sustainability of the institution that would provide microfinance. Hence, a reserve fund has also been integrated into the model. Practical implications - CWRMF represents a potential model to be implemented by humanitarian non-governmental organisations (NGOs and aid agencies to support livelihood of refugees in particular for Muslim refugees. Positive outcome is expected from the implementation of this model. This is because of the various advantages of microfinance programs not only on refugees but also on concerned NGOs, host populations and donor parties. Additionally, this paper is a set of primarily thoughts aims to open the door wider for more researchers to explore the potential of cash waqf as one of the instruments to finance refugee microenterprises and business activities. Originality/value - Recently cash waqf has been into several models for socio-economic development and poverty alleviation. This paper is proposing cash waqf as a source for a microfinance fund that can

  7. Factors Influencing Poverty Alleviation amongst Microfinance Adopting Households in Zambia

    Directory of Open Access Journals (Sweden)

    Mavhungu Abel Mafukata

    2014-04-01

    Full Text Available The main objective of this paper is to explore the factors having the most significance on the probability of the adopters of microfinance moving out of poverty in Zambia. Ninety nine (n=99 respondents were randomly and purposively selected from amongst 340 microfinance adopters of the so-called Micro Bankers Trust programme operating a microfinance business in the Makululu Compound of Kabwe, Zambia. Primary data were collected through face-to-face interviews based on a semi-structured questionnaire. The data were entered into an excel spreadsheet for analysis. The descriptive data were thereafter exported and fitted to an empirical model. The descriptive results revealed that the majority of the respondents were married, unemployed, fairly educated younger women from larger-sized poor households who drew their household income mainly from microfinance activities. The majority of the respondents thought microfinance had improved their well-being in some crucial areas. The results of the empirical model found that some respondents indeed had improved their probabilities to move out of poverty. Conclusion drawn in this paper is that microfinance does alleviate poverty of the poor. 

  8. Stabilization of Black Cotton Soil Using Micro-fine Slag

    Science.gov (United States)

    Shukla, Rajesh Prasad; Parihar, Niraj Singh

    2016-09-01

    This work presents the results of laboratory tests conducted on black cotton soil mixed with micro-fine slag. Different proportions of micro-fine slag, i.e., 3, 6, 9, 12 and 15 % were mixed with the black cotton soil to improve soil characteristics. The improvement in the characteristics of stabilized soil was assessed by evaluating the changes in the physical and strength parameters of the soil, namely, the Atterberg limits, free swell, the California Bearing Ratio (CBR), compaction parameters and Unconfined Compressive Strength (UCS). The mixing of micro-fine slag decreases the liquid limit, plasticity index and Optimum Moisture Contents (OMC) of the soil. Micro-fine slag significantly increases the plastic limit, UCS and CBR of the soil up to 6-7 % mixing, but mixing of more slag led to decrease in the UCS and CBR of the soil. The unsoaked CBR increased by a substantial amount unlike soaked CBR value. The swell potential of the soil is reduced from medium to very low. The optimum amount of micro-fine slag is found to be approximately 6-7 % by the weight of the soil.

  9. Agent-based mapping of credit risk for sustainable microfinance.

    Directory of Open Access Journals (Sweden)

    Joung-Hun Lee

    Full Text Available By drawing analogies with independent research areas, we propose an unorthodox framework for mapping microfinance credit risk--a major obstacle to the sustainability of lenders outreaching to the poor. Specifically, using the elements of network theory, we constructed an agent-based model that obeys the stylized rules of microfinance industry. We found that in a deteriorating economic environment confounded with adverse selection, a form of latent moral hazard may cause a regime shift from a high to a low loan payment probability. An after-the-fact recovery, when possible, required the economic environment to improve beyond that which led to the shift in the first place. These findings suggest a small set of measurable quantities for mapping microfinance credit risk and, consequently, for balancing the requirements to reasonably price loans and to operate on a fully self-financed basis. We illustrate how the proposed mapping works using a 10-year monthly data set from one of the best-known microfinance representatives, Grameen Bank in Bangladesh. Finally, we discuss an entirely new perspective for managing microfinance credit risk based on enticing spontaneous cooperation by building social capital.

  10. Agent-based mapping of credit risk for sustainable microfinance.

    Science.gov (United States)

    Lee, Joung-Hun; Jusup, Marko; Podobnik, Boris; Iwasa, Yoh

    2015-01-01

    By drawing analogies with independent research areas, we propose an unorthodox framework for mapping microfinance credit risk--a major obstacle to the sustainability of lenders outreaching to the poor. Specifically, using the elements of network theory, we constructed an agent-based model that obeys the stylized rules of microfinance industry. We found that in a deteriorating economic environment confounded with adverse selection, a form of latent moral hazard may cause a regime shift from a high to a low loan payment probability. An after-the-fact recovery, when possible, required the economic environment to improve beyond that which led to the shift in the first place. These findings suggest a small set of measurable quantities for mapping microfinance credit risk and, consequently, for balancing the requirements to reasonably price loans and to operate on a fully self-financed basis. We illustrate how the proposed mapping works using a 10-year monthly data set from one of the best-known microfinance representatives, Grameen Bank in Bangladesh. Finally, we discuss an entirely new perspective for managing microfinance credit risk based on enticing spontaneous cooperation by building social capital.

  11. Microfinance and Violence Against Women in Rural Guatemala.

    Science.gov (United States)

    Cepeda, Isabel; Lacalle-Calderon, Maricruz; Torralba, Miguel

    2017-11-01

    Violence against Women (VaW) has come to be recognized as a serious human rights abuse with important consequences not only for women but for whole societies. Since VaW has several manifestations, it is possible to differentiate among different types of violence. In this article, a broad theoretical framework with different dimensions of gender violence was adapted to a Latin American social and cultural context to measure three out of the five main types of violence: economic violence, emotional psychological violence, and coercive control. The goal of this article is to provide empirical evidence to determine whether access to microfinance services plays a role in reducing VaW. To this end, we designed and performed a cross-sectional study with a treatment and a control group in rural Guatemala. A sample of 883 rural women in the "Altiplano" area of Guatemala (448 women with microfinance services and 435 without) was surveyed from May to November 2012. The results of the bivariate logistic regression showed evidence of association between access to microfinance services and reduction of VaW. After adjusting for covariates, global, economic, and emotional psychological violence maintained a negative and statistically significant association with microfinance, while only coercive control showed no statistical association with microfinance services. Access to microcredits showed a very clear relationship to reducing economic and emotional violence but not coercive control, a factor that may be determined by social and cultural norms. In contrast to Status Inconsistency Theory, which has been tested primarily in Asia, our study of Guatemala showed that increased status and economic independence of women due to their participation in microfinance services reduced VaW.

  12. International For-Profit Investments in Microfinance Institutions Equity

    Directory of Open Access Journals (Sweden)

    Carlos Rodriguez Monroy

    2013-07-01

    Full Text Available Purpose: The purpose of this document is to review the funding options for Microfinance Institutions (MFIs, define the size of the holdings of international investors in MFI equity and in particular the MFIs listed in stock exchanges, analyze the characteristics of these subset of the financial world and study the stock exchange evolution of some listed MFIs amid the financial crisis. Design/methodology/approach: Since academic literature on listed MFI equity is virtually inexistent, most of the information has been obtained from the World Bank, annual accounts of the listed MFIs, stock exchanges and from equity research documents. Findings and Originality/value: Microfinance Institutions share several common characteristics that make them a resilient business and the few MFIs that are listed in stock exchanges seem to have performed better in the financial crisis. Microfinance can be considered as one of the new frontiers of the expansion of the global banking industry. Practical implications: Presently, international for-profit investors have very few ways of investing in microfinance equity. Most of the equity of the MFI equity is funded locally or thanks to the local public sector. The stock exchange listing of the MFIs should drive MFIs towards a more professional management, more transparency and better governance. Social implications: Microfinance Institutions provide credit to microenterprises in poor countries that have no other alternative sources of external capital to expand its activity. If global investors could easily invest in the listed equity of the MFIs these institutions would expand its lending books and would improve its governance, part of the population living in poor areas or with lower income could ameliorate its standard of living. Originality/value: The number of Microfinance Institutions that are professionally run like commercial banks is still scarce and even more scarce are the MFI listed in public stock exchanges

  13. Fabrication and characterization of novel gate-all-around polycrystalline silicon junctionless field-effect transistors with ultrathin horizontal tube-shape channel

    Science.gov (United States)

    Chang, You-Tai; Peng, Kang-Ping; Li, Pei-Wen; Lin, Horng-Chih

    2018-04-01

    In this paper, we report on a novel fabrication process for the production of junctionless field-effect transistors with an ultrathin polycrystalline silicon (poly-Si) tube channel in a gate-all-around (GAA) configuration. The core of the poly-Si tube channel is filled with either a silicon nitride or a silicon oxide layer, and the effects of the core layers on the device characteristics are evaluated. The devices show excellent switching performance, thanks to the combination of the ultrathin tube channel and the GAA structure. Hysteresis loops in the transfer characteristics of the nitride-core devices are observed, owing to the dynamic trapping of electrons in the nitride core.

  14. Réglementation et supervision des institutions de microfinance en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-07-30

    Jul 30, 2016 ... Book cover: Réglementation et supervision des institutions de microfinance en ... the sustainability of MFIs, the book should serve as a reference on the ... Georges Kobou is a Professor of Economics and Honorary Dean of the ...

  15. Economic analysis of the role of microfinance banks in funding ...

    African Journals Online (AJOL)

    The quest to meet the credit need of the Nigerian farmers necessitated the focus of this study. Specifically, the study examined the contribution of microfinance banks (MFBs) towards agricultural development, analyzed and compared the loans given out by these banks to agricultural sector with those given to other ...

  16. The Empirics of Microfinance: What do we Know?

    NARCIS (Netherlands)

    Lensink, B.W.; Hermes, N.

    2007-01-01

    Microfinance has received a lot of attention recently, both from policy makers as well as in academic circles. Two of the main topics that have been hotly debated are explaining joint liability group lending and its implications for reducing information asymmetries, and the trade-off between the

  17. Efficiency of Micro-fine Cement Grouting in Liquefiable Sand

    International Nuclear Information System (INIS)

    Mirjalili, Mojtaba; Mirdamadi, Alireza; Ahmadi, Alireza

    2008-01-01

    In the presence of strong ground motion, liquefaction hazards are likely to occur in saturated cohesion-less soils. The risk of liquefaction and subsequent deformation can be reduced by various ground improvement methods including the cement grouting technique. The grouting method was proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. In this research, a large-scale experiment was developed for assessment of micro-fine cement grouting effect on strength behavior and liquefaction potential of loose sand. Loose sand samples treated with micro-fine grout in multidirectional experimental model, were tested under cyclic and monotonic triaxial loading to investigate the influence of micro-fine grout on the deformation properties and pore pressure response. The behavior of pure sand was compared with the behavior of sand grouted with a micro-fine cement grout. The test results were shown that cement grouting with low concentrations significantly decreased the liquefaction potential of loose sand and related ground deformation

  18. Microfinance Programs in Uganda: An Analysis of Household ...

    African Journals Online (AJOL)

    This paper identifies a model of low-income household participation in microfinance credit programs and the effects on investment behavior from repeated access to these institutions using evidence from household survey data. The primary focus is on changes in household investment behavior, not the assessment of ...

  19. Implementing Islamic microfinance in Nigeria: a matter of equity and ...

    African Journals Online (AJOL)

    Journal of Sustainable Development Law and Policy (The) ... In the country, funding for small-scale businesses is available from both the government and the private sector. ... Keywords: Islamic microfinance; social development, distributive justice; indirect discrimination; constitutional law/human right, capability approach ...

  20. The impact of microfinance bank credit on economic development of ...

    African Journals Online (AJOL)

    This paper x-rays the contribution of microfinance bank to the economic development of Nigeria for fifteen years by using secondary data collected from the Central Bank of Nigeria records, annual reports and statistical bulletin. The ordinary least square estimation technique was adopted using linear regression model.

  1. Social and Financial Exlusion: The Role of Microfinance

    NARCIS (Netherlands)

    Becchitti, L.; Boot, A.; Lensink, B.W.; Zazzaro, A.

    2013-01-01

    Traditional banks have proved to have severe limits in mitigating financial exclusion. The microfinance revolution is intended to address this problem by devising new approaches which ease credit access for poor and uncollateralized borrowers. In this introductory essay we present a special issue of

  2. Impact of Informal Microfinance on Rural Enterprises | Oluyombo ...

    African Journals Online (AJOL)

    The paper set out to examine if rural enterprises that participate and patronise informal microfinance providers are also finding it difficult to grow their business activities. ... The findings show that members who had access to loan improved their businesses significantly through expansion of business facilities, addition of new ...

  3. The importance of geographic access for the impact of microfinance

    Czech Academy of Sciences Publication Activity Database

    Alimukhamedova, N.; Filer, R. K.; Hanousek, Jan

    2017-01-01

    Roč. 35, September (2017), s. 645-657 ISSN 0950-6764 R&D Projects: GA ČR(CZ) GA14-31783S Institutional support: RVO:67985998 Keywords : geographic access * microcredit * microfinance institutions Subject RIV: AH - Economics OBOR OECD: Finance Impact factor: 0.700, year: 2016

  4. The importance of geographic access for the impact of microfinance

    Czech Academy of Sciences Publication Activity Database

    Alimukhamedova, Nargiza; Filer, Randall K.; Hanousek, Jan

    2017-01-01

    Roč. 35, September (2017), s. 645-657 ISSN 0950-6764 Grant - others:UK(CZ) GAUK 586912 Institutional support: Progres-Q24 Keywords : geographic access * microcredit * microfinance institutions Subject RIV: AH - Economics OBOR OECD: Finance Impact factor: 0.700, year: 2016

  5. Application of MOOCs for borrowers’ financial education in microfinance

    Directory of Open Access Journals (Sweden)

    Md. Abul Kalam Siddike

    2017-06-01

    Full Text Available The main objective of this research was to explore current borrowers’ financial education in microfinance and determine the possibilities of adopting massive open online courses (MOOCs for such individuals. We adopted a semi-structured interview research strategy. A total of 25 employees and borrowers in BRAC’s (Bangladesh Rehabilitation Assistance Committee and then Bangladesh Rural Advancement Committee, currently, BRAC does not represent an acronym microfinance program were interviewed and the data were analyzed qualitatively. The results show that BRAC’s microfinance program provides borrowers’ financial education in terms of a pre-disbursement orientation and four-day training through the creation of a new role of customer service assistant. The results also reveal that edu-entertainment, easy understanding, and more borrower participation are the main possible opportunities for adopting MOOCs for borrowers’ financial education. We identified infrastructure, Internet connection, and funding as possible hindrances to adopting MOOCs for financial education. Finally, we propose a framework for adopting MOOCs for borrowers’ financial education in microfinance.

  6. Flow patterns during refrigerant condensation in smooth and enhanced tubes

    OpenAIRE

    2009-01-01

    M.Ing. The Montreal Protocol led to the phasing-out of ozone layer depleting refrigerants and replacing them with more environmentally friendly refrigerants, which in many cases caused heat transfer degradation in heat exchanger equipment. To make up for the heat transfer degradation, there was a need for the application of heat transfer enhancement techniques. One such technique is the use of micro-fin tubes as opposed to traditional smooth tubes. The purpose of this study is to develop a...

  7. Analysis Of Critical Factors Of Microfinance Institutions Of Pakistan

    Directory of Open Access Journals (Sweden)

    Ather Azim Khan

    2010-12-01

    Full Text Available This article is about the performance of Microfinance Institutions MFIs of Pakistan. In this article the types of MFIs operating is Pakistan is discussed with their details i.e. Microfinance Banks, Rural Support Programs and NGOs. Some other organizations are also involved in micro financing but their percentage is very low. It is found that Rural Support Programs RSPs are not totally involved in microfinance but have a large chunk of funds for microfinance. Micro loans are given for various purposes including starting a new business. The real theme of microcredit is to give money to a poor person to start a small or micro business and increase his family income but micro loans are often used for many other purposes such as paying another expensive loan, paying for medical expenses of bread earner of the family, marriages, construction etc. In this research work the researcher has tried to analyze the performance of MFIs of Pakistan and to find out those factors which contribute in their effectiveness. Two approaches of microfinance i.e. Institutionists Approach and Welfarists Approach are discussed. To analyze the performance of MFIs both approaches are considered i.e. Institutionists and Welfarists. Seventeen parameters are selected, many of these are financial ratios and these are divided into four groups i.e. sustainability, transparency, outreach and efficiency. Some ratios/figures of each area of these MFIs are taken in the data and analysis is performed to find out that which ones are contributing more or less. This research can be helpful for the MFIs which want to improve their performance and check their areas of significance for further improvement and development considering their approach of alleviating poverty from the society.

  8. DOES MICROFINANCE MODEL DETERMINE THE EFFECTIVENESS OF MICROFINANCE INTERVENTION IN ENHANCING MICROENTERPRISE PERFORMANCE? EVIDENCE FROM BANK RAKYAT INDONESIA

    Directory of Open Access Journals (Sweden)

    Weni Hawariyuni

    2016-06-01

    Full Text Available This study aims to investigate the effectiveness of different microfinance model in enhancing the performance of microenterprises in terms of income, fixed assets, and household expenditures. By focusing on the case of Bank Rakyat Indonesia, one of the most successful commercial microfinance providers in the world, two types of microfinance products, namely KUPEDES and KUR are being compared. The KUPEDES is original product of BRI Unit, while the KUR is a micro-product subsidized by the Indonesian government. Based on the experience of BRI Unit in Medan city, Indonesia, we assess the impact of microfinance intervention on 400 clients. The findings demonstrated that KUPEDES as original microproduct is more successful compared to KUR product in enhancing the performance of microenterprise through income, fixed assets, and household expenditures as successful indicators. =========================================== Kajian ini bertujuan untuk menginvestigasi keefektifan beragam model pendanaan mikro dalam meningkatkan performa usaha kecil dari segi pemasukan, aset tetap, dan belanja rumah tangga. Dengan fokus pada kasus Bank Rakyat Indonesia, salah satu pemberi dana mikro paling berhasil di dunia, kajian ini membandingkan dua macam produk pendanaan mikro, yaitu KUPEDES dan KUR. KUPEDES adalah produk original BRI sementara KUR adalah sebuah produk mikro yang disubsisdi oleh pemerintah Indonesia. Berdasarkan pengalaman BRI cabang Medan, Indonesia, penulis menilai dampak campur tangan pendanaan mikro terhadap 400 orang klien. Hasil penelitian menunjukkan bahwa KUPEDES sebagai produk mikro original dinilai lebih berhasil dibandingkan dengan KUR dalam meningkatkan performa usaha kecil dengan indikator kesuksesan: pemasukan, asset tetap, dan belanja rumah tangga.

  9. Non azeotrope mixing refrigerating fluids condensation outside of an horizontal tubes stack; Condensation de melanges non azeotropes de fluides frigorigenes a l'exterieur d'un faisceau de tubes horizontaux

    Energy Technology Data Exchange (ETDEWEB)

    Signe, J.Ch.

    1999-04-16

    The development of non-azeotrope mixing, as regular refrigerating fluids substitute, calls in question the experience for the design of refrigerating and cooling machinery. Studies to better understand these fluids behaviour are necessary. The aim of this thesis is the knowledge enlargement on the pure fluids and non azeotrope mixing condensation, outside of a tubes stack, and to simulate the heat transfers. The tubes stack is a condenser, type TEMA X often used in refrigerating machinery. The binary mixing HFC 134a-HFC23, allows a large sliding scale. (A.L.B.)

  10. Adopting Zero Interest Financing Model (ZIFM in Islamic Microfinance Institutions: The Case of Shariah People Credit Bank (BPRS, Indonesia

    Directory of Open Access Journals (Sweden)

    Mohd Thas Thaker Mohamed Asmy Bin

    2016-01-01

    Full Text Available Microfinance has emerged as an important instrument to alleviate poverty in many countries including in developing countries. Despite being able to demonstrate successes in the activity, conventional microfinance is not without controversy. The findings from the existing studies revealed that conventional microfinance is less effective, fail to reach the poorest people and generally have a limited effect on income. In addition, conventional microfinance also has highly criticized for charging excessive interest rates and fees to the poor entrepreneur. In some Muslim countries, conventional microfinance has always been rejected, due to its non-compliance with the Islamic principles, particularly on the issue related to interest or riba. Islamic microfinance evolved and reckoned as an alternative to its counterpart. However, the outreach of Islamic microfinance is very limited where only there is very few Islamic microfinance institutions and Islamic banks involved in microfinance activity. Also, Islamic microfinance is having an issue of convergence of activity with the conventional practices. Thus, this paper aims to propose to adopt Zero Interest Financing Model (ZIFM for Islamic microfinance institutions. This study focuses on the case of Indonesian Islamic microfinance institution namely Shariah People Credit Bank (BPRS by observing their experience and some emerging issues. The proposed model is expected to address an emerging issue in Islamic microfinance institutions.

  11. THE IMPACT OF MICROFINANCE BANKS IN RURAL AREAS OF SUB-SAHARAN AFRICA

    OpenAIRE

    Isabelle Musanganya; Chantal Nyinawumuntu; Pauline Nyirahagenimana

    2017-01-01

    Many researchers consider microfinance as a tool for poverty reduction. Even more, especially in post-conflict African countries, micro-financial institutions are seen as an opportunity of reconciliation. Lending from microfinance institutions to that from traditional banks and examine their respective effects upon economic growth has been practiced in some sub-Saharan countries. Considerable progress in research has been found that microfinance loans raise growth comparatively to that of tra...

  12. The Role of Islamic Microfinance in Socio-Economic Development in Bosnia and Herzegovina

    OpenAIRE

    Efendic, Velid; Karamustafic, Eldina

    2018-01-01

    This paper aims to explore the role of Islamic microfinance in the socio-economic development of Bosnia and Herzegovina (B&H). Due to the significant growth of the microfinance sector in the last 20 years and its impact on the country’s postwar reconstruction and development, B&H serves as a good case for this present research. The study relies on primary data collected from clients of Islamic and conventional microfinance institutions (MFI). Accordingly, the comparison betwee...

  13. Financial Performance And Corporate Governance In Microfinance: Who Drives Who? An Evidence From Asia.

    OpenAIRE

    Nawaz, Ahmad; Iqbal, Sana

    2015-01-01

    This paper models the two-way relationship between corporate governance and financial performance of microfinance institutions of Asia. Unlike previous studies, the phenomena of better corporate governance mechanisms present in more financially oriented microfinance institutions is worth investigating. Using a panel of 173 microfinance institutions in 18 Asian countries between 2007 and 2011, a comprehensive corporate governance index (CGI) based on seven corporate governance variables is bei...

  14. Microfinance and Gender: Is There a Glass Ceiling in Loan Size?

    OpenAIRE

    Agier, Isabelle; Szafarz, Ariane

    2010-01-01

    Microfinance institutions serve a majority of female borrowers. But do men and women benefit from same credit conditions? This paper investigates this issue by presenting an original model and testing its predictions on an exceptional database including 34,000 loan applications from a Brazilian microfinance institution over an eleven-year period. The model considers a lender that offers standardized loan contracts with a fixed interest rate, which is common practice in microfinance. It demons...

  15. Heat transfer characteristics of thermal energy storage for PCM (phase change material) melting in horizontal tube: Numerical and experimental investigations

    International Nuclear Information System (INIS)

    Aadmi, Moussa; Karkri, Mustapha; El Hammouti, Mimoun

    2015-01-01

    This paper focuses on the experimental and numerical study of the storage and release of thermal heat during melting and solidification of PCM (phase change material). Heat transfer enhancement techniques such as the use of conductors like graphite and metal tubes have been proven to be effective. The material used for thermal energy storage systems is a composite based on epoxy resin loaded with metal hollow tubes filled with paraffin wax. Differential Scanning Calorimetry has been used for measurement of melting enthalpy and determination of heat capacity. The thermophysical properties of the prepared composite phase change material have been characterized using a new transient hot plate apparatus. The results have shown that most important thermal properties of these composites at the solid and liquid states are the ‘‘apparent’’ thermal conductivity, the heat storage capacity and the latent heat of fusion. These experimental results have been simulated using numerical Comsol ® Multiphysics 4.3 based models with success. The results of the experimental investigation are compared favorably with the numerical results and thus serve to validate the numerical approach. - Highlights: • Phase change materials based on cylindrical used as new energy storage system. • Thermophysical properties and the melting process of composites were investigated. • All experimental results have been simulated using Comsol ® Multiphysiques. • The ability to store and release the thermal energy were investigated. • Good improvement in the thermal conductivity of composites

  16. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  17. A comparison of R-22, R-134a, R-410a, and R-407c condensation performance in smooth and enhanced tubes: Part 1, Heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Eckels, S J; Tesene, B A

    1999-07-01

    Local and average heat transfer coefficients during condensation are reported for R-22, R-134a, R-410a, and R-407c in one smooth tube and three enhanced surface tubes. The test tubes included a 3/8 inch outer diameter smooth tube, a 3/8 inch outer diameter microfin tube, a 5/16 inch outer diameter microfin tube, and a 5/8 inch outer diameter microfin tube. The local and average heat transfer coefficients were measured over a mass flux range of 92,100 lb/ft{sup 2}{center_dot}h to 442,200 lb/ft{sup 2}{center_dot}h and at saturation temperatures of 104 F and 122 F. A comparison of the performance of the different refrigerants reveals that R-134a has the highest heat transfer performance followed by R-22 and R-410a, which have similar performances. In general, R-407c had the lowest performance of the refrigerants tested. The microfin tube more than doubles the heat transfer coefficient compared to the smooth tube for all refrigerants at the low mass fluxes, but only increases the heat transfer coefficients by 50% at the highest mass flux tested. The measured heat transfer coefficients are also compared with a number of correlations for condensation.

  18. A Production Approach to Performance of Banks with Microfinance Operations

    OpenAIRE

    Emilyn Cabanda; Eleanor C. Domingo

    2014-01-01

    Banking institutions, nowadays, serve as intermediaries of funds to a variety of clients, including the micro enterprisers. This study analyzes and measures the performance of rural and thrift banks with microfinance operations in the Philippines, using combined measures of data envelopment analysis and traditional financial performance indicators. Data envelopment analysis (DEA) method is employed to measure the productive efficiency of these banks under the production approach. The variable...

  19. Evidence of Product Differentiation in the Microfinance Industry

    Science.gov (United States)

    2011-05-09

    terms of social yardsticks.6 To date, empirical studies such as Navajas et al. (2003) delve into the effects of microcredit financing in specific...2011, Jan 19). Post Carbon Institute. Retrieved March 20, 2011, from Energy Bulletin: http://www.energybulletin.net/stories/2011-01-20/ microcredit ...34Remarks by Muhammed Yunus, Managing Director, Grameen Bank.". Microcredit Summit E-News, 5(1). Mutalima, I. K. (2007). Microfinance and gener

  20. Macroeconomics of microfinance: how do the channels work?

    Czech Academy of Sciences Publication Activity Database

    Maksudova, Nargiza

    -, č. 423 (2010), s. 1-27 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Grant - others:GA UK(CZ) 52010; MŠk(CZ) SVV-2010-261801 Institutional research plan: CEZ:MSM0021620846 Keywords : microfinance * economic growth * financial intermediation * dynamic panel Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp423.pdf

  1. Social performance of microfinance institutions : theory and empirical evidence

    OpenAIRE

    Milan, Florence Marie

    2011-01-01

    Inspired by the innovative efforts of pioneers in non-governmental organizations, notably the Grameen Bank, financial services delivery to the poor has grown since the 1980?s and has been advocated as an important component of development interventions. These financial services, also known as microfinance, are believed to have positive outcomes on production, income, and consumption at household and macro-economic levels. The provocative idea that alleviating poverty can be profitable to micr...

  2. Global Financial Partnerships in Microfinance: India, Peru and Tanzania

    Directory of Open Access Journals (Sweden)

    TUBARO, Paola

    2012-06-01

    Full Text Available The paper studies the ‘wholesale’ market through which microfinance institutions operating in three contexts (Peru, Tanzania and the state of Tamil Nadu in India obtain loans from a variety of domestic and international funding bodies. The nature and characteristics of the relationships between them are captured through network analysis and visualization tools, with a dataset comprising inter-organisational lending relationships and organisations’ attributes over the years 2006-8. Focus is on the extent to which patterns in wholesale lending relationships relate to the legal status and characteristics of microfinance institutions; to the regulatory, business and social environment in which they operate; and to shifts in the balance between social and commercial interests of diverse types of lenders.The analysis brings to light considerable cross-country variation in the structure and features of wholesale lending relationships, and relates it primarily to differences in governance and regulation. On this basis, it makes the case that building a more enabling regulatory environment for funding partnerships may improve the capacity of microfinance to achieve its dual goals of poverty alleviation and financial sustainability.

  3. Earthquake parametrics based protection for microfinance disaster management in Indonesia

    Science.gov (United States)

    Sedayo, M. H.; Damanik, R.

    2017-07-01

    Financial institutions included microfinance institutions those lend money to people also face the risk when catastrophe event hit their operation area. Liquidity risk when withdrawal amount and Non Performance Loan (NPL) hiking fast in the same time could hit their cash flow. There are products in market that provide backup fund for this kind of situation. Microfinance institution needs a guideline too make contingency plan in their disaster management program. We develop a probabilistic seismic hazard, index and zonation map as a tool to help in making financial disaster impact reduction program for microfinance in Indonesia. GMPE was used to estimate PGA for each Kabupaten points. PGA to MMI conversion was done by applied empirical relationship. We used loan distribution data from Financial Service Authority and Bank Indonesia as exposure in indexing. Index level from this study could be use as rank of urgency. Probabilistic hazard map was used to pricing two backup scenarios and to make a zonation. We proposed three zones with annual average cost 0.0684‰, 0.4236‰ and 1.4064 for first scenario and 0.3588‰, 2.6112‰, and 6.0816‰ for second scenario.

  4. Targeting married women in microfinance programmes: transforming or reinforcing gender inequalities? : evidence from Ethiopia

    NARCIS (Netherlands)

    Bekele, H.

    2010-01-01

    With the expansion of microfinance programmes in the low-income countries, millions of
    poor women in these countries have been able to access microfinancial services,
    particularly microcredit and savings. The provision of microfinance services to women has
    been largely premised on

  5. Entrepreneurial and business skills and loan repayment rates of microfinance clients in Ghana

    NARCIS (Netherlands)

    Agbeko, Daniel; Block, Vincent; Omta, Onno; Velde, van der G.

    2016-01-01

    Entrepreneurial and business skills are generally considered key to microbusiness success, hence to Microfinance Institution (MFI) clients’ loan repayment as well. However, empirical evidence is largely lacking, and where present, it is inconclusive on the importance of these skills for microfinance

  6. Language and market inclusivity for women entrepreneurship: the case of microfinance

    NARCIS (Netherlands)

    Drori, Israel; Manos, Ronny; Santacreu-Vasut, Estefania; Shenkar, Oded; Shoham, Amir

    2018-01-01

    Inclusive markets are key to fostering female entrepreneurship, and the microfinance sector has recognized and acted on this. Existing research has studied how institutions and organizational factors facilitate the process by which microfinance and other financial intermediaries tackle gender-based

  7. The Effect of Credit Lines and Risks on Operations of Microfinance ...

    African Journals Online (AJOL)

    ... and make sure that loans are used for the purpose for which they were given as this will reduce the number of non performing loans. Keywords: Microfinance, Microfinance banks, Credit lines, Credit risks, Banks' depositors. International Journal of Development and Management Review (INJODEMAR) Vol. 7 June, 2012 ...

  8. THE ROLE OF MICROFINANCE IN RIGHT-BASED APPROACH TO FOOD IN AFRICA

    Directory of Open Access Journals (Sweden)

    Mago Stephen

    2014-05-01

    Full Text Available The purpose of this paper is to explore the role of microfinance to food security using the lens of the Right-Based Approach to food. The paper adopts a qualitative research methodology, following an exploratory research design. The research findings show that microfinance has a positive contribution towards rights to food and food security. However, in other African contexts, microfinance worsening the status of the poor. It was thus established that proper management of microfinance programs is likely to bring more benefits than problems. Making the ‘right to food’ and the ‘right to credit’ aspects of human rights will strengthen the productive systems of food to ensure sustainable supplies for effective food security mechanisms. The paper recommends that the linkage between microfinance and food rights be escalated to policy level discussions. Policies that promote a combination of the two rights need to be developed.

  9. Design and Baseline Findings of a Multi-site Non-randomized Evaluation of the Effect of a Health Programme on Microfinance Clients in India

    OpenAIRE

    Saha, Somen

    2013-01-01

    Microfinance is the provision of financial services for the poor. Health program through microfinance has the potential to address several access barriers to health. We report the design and baseline findings of a multi-site non-randomized evaluation of the effect of a health program on the members of two microfinance organizations from Karnataka and Gujarat states of India. Villages identified for roll-out of health services with microfinance were pair-matched with microfinance only villages...

  10. Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

    Science.gov (United States)

    Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-05-01

    Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

  11. The Malaysian microfinance system and a comparison with the Grameen Bank (Bangladesh and Bank Perkreditan Rakyat (BPR-Indonesia

    Directory of Open Access Journals (Sweden)

    Suraya Hanim Mokhtar

    2013-06-01

    Full Text Available Microfinance programme in Malaysia has been implemented since 1987 as one of the poverty eradication strategies in the country. There are three large microfinance institutions in Malaysia namely AIM, YUM and TEKUN that targeted to different groups of people. Each of the microfinance institution has its own lending systems and has been subsidised by the government since their existence. This paper compares the Malaysian subsidised microfinance institutions’ lending systems with the unsubsidised microfinance institutions such as the Grameen Bank in Bangladesh and People’s Bank (Bank Perkreditan Rakyat/BPR in Indonesia. This study found the Grameen Bank and BPR have more variety of microfinance services and flexible lending systems compared with Malaysian microfinance institutions.

  12. Réglementation et supervision des institutions de microfinance en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    30 juil. 2016 ... Les institutions de microfinance (IMF) interviennent auprès d'une clientèle qui est dans la majorité exclue du système bancaire formel. Étant donné qu'elles opèrent dans la collecte de l'épargne des pauvres en milieu rural, il est important de développer des cadres réglementaires qui protègent les clients ...

  13. Tube Length and Water Flow

    Directory of Open Access Journals (Sweden)

    Ben Ruktantichoke

    2011-06-01

    Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.

  14. The Impact of Micro-Finance on the Performance of Small-Scale ...

    African Journals Online (AJOL)

    The Impact of Micro-Finance on the Performance of Small-Scale Enterprises: A Comparison of ... PROMOTING ACCESS TO AFRICAN RESEARCH ... the impact that the study-MFIs are making on their SMEs-client in the Wa Municipality.

  15. Modalities of Microfinance Delivery in Asia and Latin America: Lessons for China

    Institute of Scientific and Technical Information of China (English)

    Heather Montgomery; John Weiss

    2006-01-01

    Microfinance, the provision of small size loans and other financial services to low income households, is often seen as the key innovation of the last 25 years in terms of means of reaching out to the poor and vulnerable. There is extensive experience in microfinance provision in both Asia and Latin America, but as yet relatively little use of the approach in China. This paper assesses different approaches to rnicrofinance delivery using a threefold distinction, the credit union approach, the non-government organization approach and the banking approach, to generalize across recent Asian and Latin American experience and discuss the role of microfinance in poverty reduction in a theoretical framework. Considering the current state of microfinance in China and international experience, we suggest the banking approach as the way to best increase outreach of micro-financial services in China.

  16. PROPOSAL FOR STRATEGIES TO BUILD MISSING FOUNDATIONS OF THE CURRENT MICROFINANCE INDUSTRY

    Directory of Open Access Journals (Sweden)

    MARTINA DRAŠAROVÁ

    2011-01-01

    Full Text Available As microfinance approaches the status of mainstream asset class, it inevitably starts to entice Socially Responsible Investment. However, precoscious capital inflow can be detrimental to all players involved. The industry is unprepared for global SRI arena. The gap between different microfinance concepts is widening, while identic terms are being used to describe different contents. The term „microfinance“ continues losing its informative value as divergent development foments nomenclative disorder. Microfinance is becoming too varied to be presented under a single term. MIVs, States and multilateral institutions must therefore in a concerted action impose basis of unified definitions, methodologies and coordinates, otherwise different concepts might mislead international public. The lack of standartized set of definitions, social impact reporting, bankruptcy procedures and evaluation infrastructure, while overstating development benefits can discredit microfinance, once SRI systems open their gates.

  17. The impact of training and monitoring on loan repayment of microfinance debtors in Ghana

    NARCIS (Netherlands)

    Agbeko, Daniel; Blok, Vincent; Omta, S.W.F.; Velde, van der G.

    2017-01-01

    Microbusiness entrepreneurs training and monitoring programmes are widely recognized as key to loan repayment performance of microfinance institution (MFI) loan clients in developing countries. Empirical evidence is, however, largely lacking and where present, not consistent. The present paper

  18. Rural Finance and Microfinance Development in Transition Countries in Southeast and East Asia

    OpenAIRE

    Llanto, Gilberto M.; Fukui, Ryu

    2006-01-01

    Microfinance is an emerging important financial subsector in Asian transition countries. Its role is to improve financial access of the poor and small economic players and thus help them to build assets, thereby contribute to poverty alleviation. This paper provides an overview of rural finance and microfinance development in transition countries in Southeast and East Asia—Cambodia, Lao PDR, Myanmar, Vietnam, and Mongolia—focusing on the institutional evolution and the inter-relation between ...

  19. Targeting married women in microfinance programmes: transforming or reinforcing gender inequalities? : evidence from Ethiopia

    OpenAIRE

    Bekele, H.

    2010-01-01

    With the expansion of microfinance programmes in the low-income countries, millions of poor women in these countries have been able to access microfinancial services, particularly microcredit and savings. The provision of microfinance services to women has been largely premised on the assumption that credit facilitates or expands women’s selfemployment opportunities, and consequently leads to their empowerment. In recent years, however, this proposition is under scrutiny and debate, as t...

  20. Microfinance institutions' failure to address poverty: A narrative critical literature review

    OpenAIRE

    Guðjónsson, Sigurður

    2017-01-01

    This critical literature review begins by giving a short introduction to the microfinance industry. Microfinance institutions (MFIs) are explained and an account is given of their dual performance goals of financial performance (‘financial sustainability’) and social performance (‘outreach’). While MFIs’ social performance is directly aimed at poverty reduction, it is noteworthy that often they fail to address poverty (i.e., they fail to deliver outreach). The aim of the paper is to answer th...

  1. An adult learning perspective on disability and microfinance: The case of Katureebe.

    Science.gov (United States)

    Nuwagaba, Ephraim L; Rule, Peter N

    2016-01-01

    Despite Uganda's progress in promoting affirmative action for persons with disabilities and its strategy of using microfinance to fight poverty, access to microfinance services by persons with disabilities is still problematic due to barriers, characterised by discrepancies between policies and practices. Regarding education, the affirmative action in favour of learners with disabilities has not translated into actual learning opportunities due to personal and environmental barriers. The study on which this article is based investigated the non-formal and informal adult learning practices regarding microfinance that persons with disabilities engaged in. This article seeks to illuminate the barriers that a person with a visual impairment encountered while learning about and engaging with microfinance and the strategies that he developed to overcome them. This was a case study, framed within the social model of disability and critical research paradigm. Data were collected through in-depth interviews of a person with visual impairment and observations of the environment in which adult learning and engagement with Savings and Credit Cooperative Organisations (SACCOs) occurred. Findings indicate that the person with a visual disability faced barriers to learning about microfinance services. He experienced barriers in an integrated manner and developed strategies to overcome these barriers. The barriers and strategies are theorised using the social model of disability. The case of a person with visual impairment suggests that persons with disabilities face multiple barriers regarding microfinance, including social, psychological and educational. However, his own agency and attitudes were also of importance as they influenced his learning. Viewing these barriers as blockades can lead to non-participation in learning and engagement with microfinance whereas viewing them as surmountable hurdles can potentially motivate participants to succeed in learning about and engaging

  2. Evaluating the effect of integrated microfinance and health interventions: an updated review of the evidence.

    Science.gov (United States)

    Lorenzetti, Lara M J; Leatherman, Sheila; Flax, Valerie L

    2017-06-01

    Solutions delivered within firm sectoral boundaries are inadequate in achieving income security and better health for poor populations. Integrated microfinance and health interventions leverage networks of women to promote financial inclusion, build livelihoods, and safeguard against high cost illnesses. Our understanding of the effect of integrated interventions has been limited by variability in intervention, outcome, design, and methodological rigour. This systematic review synthesises the literature through 2015 to understand the effect of integrated microfinance and health programs. We searched PubMed, Scopus, Embase, EconLit, and Global Health databases and sourced bibliographies, identifying 964 articles exclusive of duplicates. Title, abstract, and full text review yielded 35 articles. Articles evaluated the effect of intentionally integrated microfinance and health programs on client outcomes. We rated the quality of evidence for each article. Most interventions combined microfinance with health education, which demonstrated positive effects on health knowledge and behaviours, though not health status. Among programs that integrated microfinance with other health components ( i.e. health micro-insurance, linkages to health providers, and access to health products), results were generally positive but mixed due to the smaller number and quality of studies. Interventions combining multiple health components in a given study demonstrated positive effects, though it was unclear which component was driving the effect. Most articles (57%) were moderate in quality. Integrated microfinance and health education programs were effective, though longer intervention periods are necessary to measure more complex pathways to health status. The effect of microfinance combined with other health components was less clear. Stronger randomized research designs with multiple study arms are required to improve evidence and disentangle the effects of multiple component

  3. Moving up the sanitation ladder with the help of microfinance in urban Malawi

    OpenAIRE

    Chunga, R; Jenkins, MW; Ensink, J; Brown, J

    2017-01-01

    We carried out a stated preference survey in Malawi to examine whether access to microfinance for sanitation would significantly increase the proportion of households upgrading to improved pit latrines or alternative improved sanitation technologies (urine diverting dry toilet, fossa alterna, pour flush). We presented a range of sanitation options at local market prices, initially without and then with a real microfinance option, to 1,300 households sampled across 27 low-income urban settleme...

  4. The role of a microfinance program on HIV risk behavior among Haitian women.

    Science.gov (United States)

    Rosenberg, Molly S; Seavey, Brian K; Jules, Reginal; Kershaw, Trace S

    2011-07-01

    Microfinance loans targeted at vulnerable female populations have the potential to foster female economic independence, possibly leading to the negotiation of safer sexual practices and reduced HIV risk. This study assessed the relationship between experience with microfinance loans and HIV risk behavior among 192 female clients of the Haitian microfinance organization Fonkoze. Clients with longer microfinance experience were generally found to have lower indicators of HIV risk behavior and higher indicators of relationship power compared to those with shorter experience. In particular, those with longer memberships were 72% less likely to report partner infidelity, were 3.95 times more likely to use condoms with an unfaithful partner, and had higher average general power index scores compared to those with shorter experience. This study provides evidence that long-term exposure to microfinance is associated with reduced HIV risk behavior in Haitian women and that this reduction may be partly regulated by influencing relationship power. These results suggest the need to further explore the use of microfinance as a tool to prevent the spread of HIV.

  5. Microfinance As A Tool For Poverty Reduction: A Study Of Jordan

    Directory of Open Access Journals (Sweden)

    Žiaková M.

    2015-12-01

    Full Text Available The aim of this study is to evaluate the impact of microfinance on the poor, particularly in the specific areas of economic and social development of people and their employment. The research was carried out in Jordan, a country with a well-developed microfinance sector. The results have shown that microfinance has led to an improvement in the financial and social situation of the poor, especially for female clients of microfinance institutions. Interestingly, the higher income of clients has not caused higher expenditure on their basic needs, but rather people have generated saving for their future and used the additional money for education. According to the results of the microfinance impact assessment, it can be assumed that people, particularly females, prefer to improve the social situation for future generations. Based on this finding, we consider microfinance an effective tool for breaking the vicious circles of poverty, especially in Jordan. Furthermore, microcredits have facilitated in increasing employment for the poor, mainly through self-employment. It is believed that there exists a direct connection to the future expansion of microcredits that will lead to the development of small businesses with a promising impact on employability throughout the population structure.

  6. Women's empowerment and micro-finance programmes: strategies for increasing impact.

    Science.gov (United States)

    Mayoux, L

    1998-05-01

    This study summarizes findings from a pilot project that distributed information and ran workshops in Ethiopia, Ghana, and India, on women's empowerment and microfinance. The project was funded by the British Small Enterprise Development Fund of the Department of International Development. Links between microfinance and women's empowerment are viewed as optimistic, limited by design, cost effective in eliminating poverty, and a misplaced diversion of resources. Microfinance programs range from small scale self-help groups to large poverty-targeted banks. One model may vary in delivery, group functions and structures, and complementary services. This project identified 3 contrasting approaches to microfinance and women's empowerment: the financial sustainability approach, the integrated community development approach, and the feminist empowerment approach. However, program evaluations revealed the need to question the assumptions underlying all 3 approaches. In most programs, women benefited to a limited degree. Many women did not control the loan use. Most women were engaged in low paid, traditionally female activities, and increases in income were small. Resources and time invested in economic activity were limited by responsibility for household consumption and unpaid domestic work. Microfinance programs sometimes created domestic tension between spouses and loss of spousal income and support. Group repayment pressures sometimes created pressures between women. Many women focused on personal rather than social objectives. The author proposes a gender strategy for microfinance and sets priorities for further research.

  7. A systematic review of microfinance and women's health literature: Directions for future research.

    Science.gov (United States)

    O'Malley, T L; Burke, J G

    2017-11-01

    While growing evidence suggests that microfinance is an effective approach for improved women's health, a significant gap remains in our understanding. The objective of this review is to synthesise the findings from published literature focused on microfinance and health issues particularly affecting women, including HIV/AIDS, reproductive health, mental health, and violence. Forty-one articles that examine the impact of microfinance participation on women's health were identified through a systematic search of electronic databases, coded using a structured abstraction form, and synthesised. Review results indicate that the impact of microfinance on women's health is an area in great need of research and publication attention. Varied quality and reporting in the identified articles restricted the ability to draw concrete conclusions regarding the relationship between microfinance participation and women's health, but led to the identification of current gaps in existing published research. Future research should work to address the recommendations provided in order to offer additional evidence to better understand the use of microfinance programming as a structural intervention to improve women's health.

  8. Microfinance Participation and Domestic Violence in Bangladesh: Results From a Nationally Representative Survey.

    Science.gov (United States)

    Murshid, Nadine Shaanta; Akincigil, Ayse; Zippay, Allison

    2016-05-01

    This article examines domestic violence among women who participate in microfinance in Bangladesh. Secondary analysis of survey data from nationally representative Bangladesh Demographic and Health Survey was used to investigate the association between microfinance participation and domestic violence of 4,163 ever-married women between the ages of 18 and 49 years. Outcome measure is experience of domestic violence as measured by a modified Conflict Tactics Scale (CTS) and predictor variables include microfinance, binary indicator of relatively better economic status, autonomy, decision-making power, and demographic variables. The likelihood of experiencing domestic violence was not found to vary with microfinance participation. However, the interaction effect of microfinance and better economic status was found to be significantly associated with domestic violence (9% increased probability). Experience of domestic violence was negatively associated with older age, higher education of the husband, and autonomy. In Bangladesh, microfinance participation may be associated with a higher probability of experiencing domestic violence for women with relatively better economic status, but not for the poorest of the poor. © The Author(s) 2015.

  9. Government-sponsored microfinance program: Joint liability vs. individual liability

    Directory of Open Access Journals (Sweden)

    Arghya Kusum Mukherjee

    2014-12-01

    Full Text Available Swarnajayanti Gram Swarozgar Yojana (SGSY is a government-sponsored microfinance program. The scheme is based on four features: group lending with joint liability, progressive lending, back-ended subsidy, and social capital. We propose a new model of SGSY having these features: group lending with individual liability, progressive lending, back-ended subsidy, and social capital. “Joint liability” clause of the existing model is replaced with individual liability in the new model. The paper shows that problem of adverse selection is removed in both models, i.e. in “SGSY with group lending and joint liability” and “SGSY with group lending and individual liability.” The problem of “moral hazard” is more severe in the existing model of SGSY compared with the proposed model of SGSY. Borrowers are also benefitted from participation in the proposed scheme of SGSY than that in the existing model of SGSY.

  10. Community Empowerment through Islamic Microfinances: Perceptions in Comparison

    Directory of Open Access Journals (Sweden)

    Lathif Hanafir Rifqi

    2017-04-01

    Full Text Available BMT (Islamic saving and loan cooperative has continuosly been one of the Islamic microfinance institutions playing a significant role in empowering economic society. There has been a number of research discussing on the effort, however none of them discussed on the perception between the empowers and the empowered group. Comparing these perceptions is a salient effort to find similarities or differencess of perceptions. This research seeks to compare empowerment perception between two organizations. One hand hand, the first party taking BMT BIF Ledok Timoho as the empowering organization and on the other hand focusing on a group of women's empowerment Ledok Timoho. Gathering data through doing observation and in-depth interview had been employed with selecting the purposive informants that contains a BMT BIF and four empowerment group representatives. To conclude, this research found that are similarities of perceptions on empowerment goals, process, outcomes and constraints.

  11. Global recession and microfinance risk governance in developing countries

    Directory of Open Access Journals (Sweden)

    Roberto Moro Visconti

    2011-09-01

    Full Text Available Global recession, started in 2008, is still proving an unresolved perfect storm and the financial crisis has affected also the real economy, creating widespread social unrest. Microfinance institutions (MFIs in developing countries seem however less affected by the worldwide turmoil, due to their segmentation and resilience to external shocks. Recession has a big impact on governance mechanisms, altering the equilibriums among different stakeholders and increasing the risk of investment returns; any governance improvement is highly welcome and recommended. No governance, no money for growth or bare survival. In the confused phase we are living in, at the moment there are not evident winners, but the underbanked poorest, unless properly supported, once again risk being the ultimate losers.

  12. Gendered Poverty and Education: Moving beyond Access to Expanding Freedoms through Microfinance Policy in India and Australia

    Science.gov (United States)

    Voola, Archana

    2016-01-01

    Microfinance has been recognized globally as a poverty alleviating strategy and particularly as a gender equality enhancing approach. There have been immense, intense and nuanced debates in the field of international development, feminist studies and comparative social policy regarding the role of microfinance in addressing gendered poverty. This…

  13. The Impact of Information and Communication Technology on Intermediation, Outreach, and Decision Rights in the Microfinance Industry

    Science.gov (United States)

    Weber, David Michael

    2012-01-01

    The microfinance industry provides financial services to the world's poor in hopes of moving individuals and families out of poverty. This dissertation document suggests that information and communication technologies (ICTs) are changing the microfinance industry, especially given recent advancements in mobile banking, Internet usage and…

  14. Banking is for Others: Contradictions of Microfinance in the Ghanaian Market

    Directory of Open Access Journals (Sweden)

    Irene Pang

    2016-08-01

    Full Text Available Recent literature on microfinance has observed that commercial microfinance programs that achieve financial sustainability largely fail to reach the poor (Hulme 2000; Mayoux 2000; Cull, Demirgüç-Kunt, and Morduch 2007. Most studies rely on institutional explanations for this failure (Battilana and Dorado 2010; Pache and Santos 2010; Canales 2011. Using a Braudelian conceptualization of a fragmented, three-tiered capitalist world-economy, this study examines how Ghanaian market women finance their businesses within the bottom layer of the capitalist world-economy, and why, despite the availability of commercial microfinance, they continue to rely on informal finance. I argue that commercial microfinance is structurally constrained by contradictions between the profit-driven logic of the upper layers of the capitalist world-economy and the socially-embedded and subsistence-driven logic that organizes the market in which market women operate. I also show that, to the extent that commercial microfinance partially penetrates the market, it disrupts the circulation of financial resources and weakens existing social and economic networks within the community.

  15. Microfinance participation and contraceptive decision-making: results from a national sample of women in Bangladesh.

    Science.gov (United States)

    Murshid, N S; Ely, G E

    2016-10-01

    Our objective was to assess whether microfinance participation affords greater contraceptive decision-making power to women. Population based secondary data analysis. In this cross-sectional study using nationally representative data from the Bangladesh Demographic and Health Survey 2011 we conducted multinomial logistic regression to estimate the odds of contraceptive decision-making by respondents and their husbands based on microfinance participation. Microfinance participation was measured as a dichotomous variable and contraceptive decision-making was conceptualized based on who made decisions about contraceptive use: respondents only; their partners or husbands only; or both. The odds of decision-making by the respondent, with the reference case being joint decision-making, were higher for microfinance participants, but they were not significant. The odds of decision-making by the husband, with the reference case again being joint decision-making, were significantly lower among men who were partnered with women who participated in microfinance (RRR = 0.70, P participation by women allowed men to share decision-making power with their wives that resulted in higher odds of joint decision-making. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  16. Capacity, Debility and Differential Inclusion: The Politics of Microfinance in South India

    Directory of Open Access Journals (Sweden)

    Vandana Chaudhry

    2018-02-01

    Full Text Available This article uses a critical disability lens to map how differential inclusion shatters the promise of democratizing capital in microfinance. Based on an ethnographic study of disability microfinance projects of the World Bank in India, it traces the dynamics of inclusion through the exclusion of debilitated bodies that cannot be capacitated within the neoliberal logic of entrepreneurship. A disability perspective brings into relief the pernicious ways that microfinance operates through webs of ableism, capitalism, and other axes of power and domination. It builds upon and contributes to the ongoing debates on microfinance as a form of neoliberal populism by showing what disability has to say about political futures amidst globalizing desires for inclusion, social mobility, and democratizing access to capital. Examining disability as a culturally-specific configuration of precarity and marginalization that is deepened by microfinance programs allows us to challenge the inclusionist claims of finance capital, and re-envision ethically and socially responsible frameworks. Generating culturally grounded knowledge on disability in the global south, this article also makes an important contribution to the field of disability studies, which scholars have argued remains implicated within the hegemony of 'scholarly colonialism' (Meekosha, 2011.

  17. Financial resources of the microfinance sector: Securitisation deals – Issues and challenges Interview with the MFIs Grameen Koota and Equitas

    Directory of Open Access Journals (Sweden)

    M. Jayadev

    2012-03-01

    Full Text Available Securitisation has emerged as an innovative and structured product that meets the funding requirements of microfinance institutions (MFIs. This paper provides a contextual note on the microfinance sector and the financial sources of MFIs. The note is followed by interviews with senior executives of two microfinance institutions on the securitisation deals of microfinance institutions. We argue in our note that the microfinance sector needs to be revived to meet the broader goal of financial inclusion. Banks and MFIs have to collaborate with each other to meet this objective. Banks have to encourage MFIs to shift over to low cost finance either by giving direct loans or through innovative deals like securitisation. Commercial banks have to leverage MFIs for their origination and recovery capabilities in small loans.

  18. Energy-microfinance intervention for low income households in India

    Science.gov (United States)

    Rao, P. Sharath Chandra

    In India, limited energy access and energy inequity hamper the lives of low income households. Traditional fuels such as firewood and dung cake account for 84 percent and 32 percent of the rural and urban household cooking energy (NSSO, 2007). With 412 million people without access to electricity in 2005, India hosts the world's largest such population (IEA, 2007). But, low income households still spend 9 - 11.7 percent1 of their incomes on inefficient forms of energy while wealthy households spend less than 5 percent on better energy products (Saghir, 2005). Renewable energy technologies coupled with innovative financial products can address the energy access problem facing the low income households in India (MacLean & Siegel, 2007; REEEP, 2009). Nevertheless, the low income households continue to face low access to mainstream finance for purchasing renewable energy technology at terms that meet their monthly energy related expenditure (ESMAP, 2004a; SEEP, 2008a) and low or no access to energy services (Ailawadi & Bhattacharyya, 2006; Modi et. al., 2006). The lack of energy-finance options has left the marginalized population with little means to break the dependence on traditional fuels. This dissertation proposes an energy microfinance intervention to address the present situation. It designed a loan product dedicated to the purchase of renewable energy technologies while taking into account the low and irregular cash flows of the low income households. The arguments presented in this dissertation are based on a six-month pilot project using this product designed and developed by the author in conjunction with a microfinance institution and its low income clients and Energy Service Companies in the state of Karnataka. Finding the right stakeholders and establishing a joint agreement, obtaining grant money for conducting the technology dissemination workshops and forming a clear procedure for commissioning the project, are the key lessons learnt from this study

  19. Improving maternal healthcare utilisation in sub-Saharan Africa through micro-finance.

    Science.gov (United States)

    Abekah-Nkrumah, Gordon; Abor, Patience Aseweh; Abor, Joshua; Adjasi, Charles K D

    2011-01-01

    This paper aims to examine links between women's access to micro-finance and how they use maternal healthcare services in sub-Saharan Africa (SSA). The authors use theoretical and empirical literature to propose a framework to sustain and improve women's access to maternal healthcare services through micro-financing. It is found that improved access to micro-finance by women, combined with education may enhance maternal health service uptake. The paper does not consider empirical data in the analysis. The authors advocate empirically testing the framework proposed in other SSA countries. It is important to empower women by facilitating their access to education and micro-finance. This has implications for improving maternal healthcare utilization in SSA. The paper moves beyond poor access to maternal health services in SSA and proposes a framework for providing sustainable solutions.

  20. EMPIRICAL ASSESSMENT OF MICROFINANCE BANKS IN NIGERIA USING EFQM EXCELLENCE MODEL

    Directory of Open Access Journals (Sweden)

    Chijioke Nwachukwu

    2017-06-01

    Full Text Available Measuring the performance of microfinance banks ensure that the banks create value for their various stakeholders. Achieving and sustaining superior business performance is important for organisations. The goal of this study is to assess microfinance banks in Nigeria using EFQM Excellence Model. The study adapts the EFQM self- assessment questionnaire for collecting data from 53 senior staff of selected Microfinance banks in Nigeria. In analyzing our data, Pearson correlation, ANOVA, and multiple regression techniques were used. The result shows that a significant positive association exists between the enablers (leadership, strategy, people, partnerships and resources, processes, products, and services and results (customer, people, society, and business criterion. More important, all the 4 hypotheses are supported. The authors suggest that a robust performance management system that integrates leadership, strategy, people, resources, processes, products, and services are important to achieve and sustain excellent results for various stakeholders.

  1. An empirical approach to the credit risk assessment of a microfinance institution in Peru

    Directory of Open Access Journals (Sweden)

    Juan Lara Rubio

    2011-06-01

    Full Text Available The growth of micro-credit along with the excellent conditions to carry out microfinance activity in the economy and financial system of the Republic of Peru are pushing for Microfinance Institutions (IMF increased competition with banks in this segment business. Like in commercial banks, in microfinance questions such as: is this customer profitable?, What is the credit limit that I must accept to his/her application?, What interest rate should I charge to him/ her?, How I can reduce the risk default?, etc., are matters to be assessed properly. We propose a method that could facilitate improvement in customer qualification between failed and not failed. To this end, we propose a methodology that analyzes credit risk in the provision of microcredit through the design of a credit scoring model that we apply to a Development Agency for Small and Micro Enterprise (EDPYME, which is an IMF under the supervision by the Banking and Insurance Superintendency (SBS.

  2. The experiments of resonance tube method and resonator method ...

    Indian Academy of Sciences (India)

    Take a 50 ml measuring cylinder or a big test tube and hold it vertical using a stand. Add some water in the tube so that the horizontal surface of water is above the rounded bottom. Stick a strip of graph paper or ruler on the tube and mark a horizontal line corresponding to the water level. Keep the speaker pointing towards.

  3. Using microfinance to facilitate household investment in sanitation in rural Cambodia.

    Science.gov (United States)

    Geissler, Kimberley H; Goldberg, Jeffrey; Leatherman, Sheila

    2016-11-01

    Improved sanitation access is extremely low in rural Cambodia. Non-governmental organizations have helped build local supply side latrine markets to promote household latrine purchase and use, but households cite inability to pay as a key barrier to purchase. To examine the extent to which microfinance can be used to facilitate household investment in sanitation, we applied a two-pronged assessment: (1) to address the gap between interest in and use of microfinance, we conducted a pilot study to assess microfinance demand and feasibility of integration with a sanitation marketing program and (2) using a household survey (n = 935) at latrine sales events in two rural provinces, we assessed attitudes about microfinance and financing for sanitation. We found substantial stated intent to use a microfinance institution (MFI) loan to purchase a latrine (27%). Five percent of current owners used an MFI loan for latrine purchase. Credit officers attended 159 events, with 4761 individuals attending. Actual loan applications were low, with 4% of sales events attendees applying for a loan immediately following the event (mean = 1.7 loans per event). Ongoing coordination was challenging, requiring management commitment from the sanitation marketing program and commitment to social responsibility from the MFI. Given the importance of improving sanitation coverage and concomitant health impacts, linking functional sanitation markets to already operational finance markets has the potential to give individuals and households more financial flexibility. Further product research and better integration of private vendors and financing modalities are necessary to create a scalable microfinance option for sanitation markets. © The Author 2016. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Application and Prospect of Superconducting High Gradient Magnetic Separation in Disposal of Micro-fine Tailings

    Science.gov (United States)

    Yang, Changqiao; Li, Suqin; Guo, Zijie; Kong, Jiawei

    2017-12-01

    Magnetic separation technology is playing an increasingly important role in the field of environmental protection such as waste gas, waste water and solid waste treatment. As a new type of solid waste treatment technology, superconducting high gradient magnetic separation (HGMS) is mainly applied in the separation of micro-fine weakly magnetic particles because of the advantages of high separation efficiency, energy saving, simple equipment and easy automation. In this paper, the basic principle of superconducting HGMS was firstly introduced, then the research status of scholars at home and aboard on the disposal of micro-fine tailings were summarized. Finally, the direction of development for HGMS was put forward.

  5. Microfinance Participation, Control Over Resources, and Justification of IPV: Results From a Nationally Representative Sample of Women.

    Science.gov (United States)

    Murshid, Nadine Shaanta

    2016-04-13

    A high percentage of men and women are purported to justify intimate partner violence (IPV) in countries that are steeped in patriarchy even in the presence of programs such as microfinance that aim to address gender equity. This article examines two assertions that emerge from the literature on microfinance and its potential for positive outcomes for women who participate in it: (a) Microfinance participation is associated with reduced justification of IPV, and (b) microfinance participants with control over their own resources are less likely to justify IPV when compared with microfinance participants who do not have control over their resources. Couples data from a nationally representative survey, the Bangladesh Demographic and Health Survey, were used in the present study. Propensity score matching and logistic regression analyses were conducted to reveal that (a) microfinance participation was not associated with justification of IPV and that (b) women who participated in microfinance were less likely to justify IPV when they had no control over their resources. Implications for practitioners and policymakers are discussed. © The Author(s) 2016.

  6. Men's response to their wives' participation in microfinance: perpetration and justification of intimate partner violence in Bangladesh.

    Science.gov (United States)

    Murshid, N S

    2016-12-01

    The present study adds to extant literature on the association between microfinance participation and intimate partner violence (IPV) by assessing a national sample of men married to microfinance participants. The key objective was to assess whether there was a positive association between wives' microfinance participation and men's perpetration and justification of IPV in urban areas of Bangladesh. This study is based on a population-based secondary data analysis. In this cross-sectional study, data from a national sample of men from the 2007 Bangladesh Demographic and Health Survey were analysed using logistic regression analyses. IPV perpetration was measured using a modified Conflict Tactics Scale and justification of IPV was measured based on 'justification of wife beating' statements with which men agreed or disagreed. Men married to microfinance participants were not significantly different from men married to non-participants of microfinance in terms of IPV perpetration in both urban and rural areas. However, the interaction effect of wives' microfinance participation and urban living on men's justification of IPV revealed a significant and positive beta coefficient. Specifically, wives' participation in microfinance was positively associated with men's justification of IPV in urban areas (β = 0.51, P men and women. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  7. Microfinance Institutions' Successful Delivery Of Micronutrient Powders: A Randomized Trial In Rural Haiti.

    Science.gov (United States)

    Baum, Aaron; Elize, Wesly; Jean-Louis, Florence

    2017-11-01

    Globally, two-thirds of child deaths could be prevented by increased provision of health interventions such as vaccines, micronutrient supplements, and water purification tablets. We report the results from a randomized controlled trial in Haiti during 2012 that tested whether microfinance institutions-which reach 200 million households worldwide-can effectively deliver health products. These institutions provide loans to underserved entrepreneurs, primarily poor women in rural areas. In the intervention group, micronutrient powders to improve the nutrition of young children were distributed at regularly occurring microfinance meetings by a trained borrower. In both the control and the intervention groups, nurses led seminars on nutrition and extended breastfeeding during microfinance meetings. At three-month follow-up, the mean difference in hemoglobin concentration between children in the intervention group and those in the control group was 0.28 grams per deciliter (g/dL)-with a subsample of younger children (under two years of age) showing greater relative improvement (0.46 g/dL)-and the odds ratio for children in the intervention group meeting the diagnostic criteria for anemia was 0.64. The results are similar to those of previous studies that evaluated micronutrient powder distribution through dedicated health institutions. Our findings suggest that microfinance institutions are a promising platform for the large-scale delivery of health products in low-income countries.

  8. Econometric analyses of microfinance credit group formation, contractual risks and welfare impacts in Northern Ethiopia

    NARCIS (Netherlands)

    Berhane Tesfay, G.

    2009-01-01

    Key words
    Microfinance, joint liability, contractual risk, group formation, risk-matching, impact evaluation, Panel data econometrics, dynamic panel probit, trend models, fixed-effects, composite counterfactuals, propensity score matching, farm households, Ethiopia.

    Lack of

  9. Akhuwat Microfinance: Participation, Impact and Gender-Based Heterogeneity in Business Returns

    NARCIS (Netherlands)

    Maazullah

    2016-01-01

    markdownabstractWe conducted this research in collaboration with Akhuwat – a microfinance organization in Pakistan which provides interest free loans to the poor. The research findings are reported in three core essays. __The first essay__ explores reasons of non-participation in Akhuwat

  10. Microfinance et les TIC : soutien au programme STAR de Hivos en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Open source framework : opportunities for microfinance ... Le Conseil des gouverneurs félicite Jean Lebel pour son nouveau mandat au ... CDRI est heureux d'annoncer que le premier appel à candidatures pour les bourses de début de.

  11. The impact of gender and business training for female microfinance clients in Vietnam

    NARCIS (Netherlands)

    Vu, Nhung; van Velzen, Rosine; Lensink, Robert; Bulte, Erwin H.

    2015-01-01

    This study documents the impact of offering a gender and business training to female microfinance clients in Vietnam on business outcomes and women empowerment using a randomised controlled trial. Many researchers argue that management and business skills are crucial to increase productivity and

  12. La microfinance et les TIC : systèmes d'information de gestion en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Extrants. Études. MIFOS presentation. 46627. Études. Research results : analyzing the impact of introducing an automated management information system within microfinance institutions. 46626. Études. ICT considerations for MFIs. 46625. Études. Open MIS and micro-banking for everyone! 46624 ...

  13. How microfinance empowers women in Côte d'Ivoire

    NARCIS (Netherlands)

    Fofana, B.; Antonides, G.; Niehof, A.; Ophem, van J.A.C.

    2015-01-01

    This study deals with the effect of microcredit on women’s livelihood and empowerment in rural areas of Côte d’Ivoire. A cross-section survey was conducted among 185 borrowers from two microfinance institutions and 209 non-borrowers in rural areas of Côte d’Ivoire. In addition, a focus group

  14. Impact assessment of microfinance institutions in Nigeria: gaps, inefficiencies and emerging solutions

    Directory of Open Access Journals (Sweden)

    Okunnu,Mustapha Abiodun

    2010-12-01

    Full Text Available Microfinance has received a lot of attention recently, both from policy makers as well as in academic circles. Microfinance interventions have contributed significantly to small business development. The success story of microfinance schemes notwithstanding, they have the problem of excluding the poorest of the poor and at times do not have the characteristics that encourage entrepreneurial development. This paper reviews the achievements of the ‘microfinance revolution’, through reference to the now extensive literature. It finds that there are many opportunities to improve and innovate. The interpretation reveals that as more the number of years of formal education of respondents, the more the level of enlightenment which will determine the level of annual savings. It is also confirmed that there is negative relationship between the nature of business enterprises and social cultural expenses. This negative relationship could be explained as the more the expenditure on social and cultural issues the less the annual savings. To illustrate this finding, the paper concentrates on examining what we need to know to design and deliver better financial products to the poor, especially the poorest. It argues that financial services for the poor are essentially a matter of helping the poor turn their savings into sums large enough to satisfy a wide range of business, consumption, personal, social and asset-building needs.

  15. La microfinance et les TIC : systèmes d'information de gestion en ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Hivos procède actuellement à l'exécution d'un programme (STAR) visant à mettre les technologies de l'information et de la communication (TIC) au service des ONG qui oeuvrent dans les ... Research results : analyzing the impact of introducing an automated management information system within microfinance institutions.

  16. A Three-Dimensional Model of Women's Empowerment : Implications in the Field of Microfinance and Future Directions

    NARCIS (Netherlands)

    Huis, Marloes A.; Hansen, Nina; Otten, Sabine; Lensink, Robert

    2017-01-01

    Women's empowerment is an important goal in achieving sustainable development worldwide. Offering access to microfinance services to women is one way to increase women's empowerment. However, empirical evidence provides mixed results with respect to its effectiveness. We reviewed previous research

  17. Conceptual optimization using genetic algorithms for tube in tube structures

    International Nuclear Information System (INIS)

    Pârv, Bianca Roxana; Hulea, Radu; Mojolic, Cristian

    2015-01-01

    The purpose of this article is to optimize the tube in tube structural systems for tall buildings under the horizontal wind loads. It is well-known that the horizontal wind loads is the main criteria when choosing the structural system, the types and the dimensions of structural elements in the majority of tall buildings. Thus, the structural response of tall buildings under the horizontal wind loads will be analyzed for 40 story buildings and a total height of 120 meters; the horizontal dimensions will be 30m × 30m for the first two optimization problems and 15m × 15m for the third. The optimization problems will have the following as objective function the cross section area, as restrictions the displacement of the building< the admissible displacement (H/500), and as variables the cross section dimensions of the structural elements

  18. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  19. Crowdsourced Microfinance for Energy Efficiency in Underserved Communities

    Energy Technology Data Exchange (ETDEWEB)

    Baird, Donnel [BlocPower LLC, New York, NY (United States); Cox, Morris [BlocPower LLC, New York, NY (United States); Harmarneh, Sarey [BlocPower LLC, New York, NY (United States); Zheng, Chen [BlocPower LLC, New York, NY (United States)

    2017-06-21

    BlocPower’s mission is to provide access to energy efficiency financing for underserved communities across the United States. This project, “Crowdsourced Microfinance for Energy Efficiency in Underserved Communities,” is an extension of that goal and is grounded in the principles of providing engineering and financing services to those in need. The project is based on the creation of a BlocPower Marketplace as a central hub for connecting shovel-ready green buildings to institutional investors. This ‘connection’ entails using online crowdfunding to aggregate debt and equity capital from institutional investors to connect to customers (building owners) across various financial portfolios. BlocPower Marketplace is intended to bring social, environmental, and financial returns to investors while also decreasing investor risk by loaning out funds for energy installations in individual buildings. In detail, the intended benefits of crowdsourcing are two-sided. Firstly, for building owners, clean energy retrofit installations improve building operations, reduce utility costs, and reduce harmful impacts to their surrounding environment. Secondly, for institutional investors, they gain access to a new market of energy efficiency and are able to provide debt or equity capital with high financial returns. This gives investors the opportunity to create social and environmental impact in communities around the country as well. With this in mind, BlocPower designed the marketplace to specifically answer exploratory research questions with respect to the pricing of energy financing. Institutional investors typically charge high rates on project financing solutions in the energy space, particularly in low and middle-income communities, because of fears that required debt service will not be made. This makes access to energy capital exorbitantly difficult for those that need it the most. Through this project, BlocPower tested investor appetite to determine if

  20. Tube plug

    International Nuclear Information System (INIS)

    Zafred, P. R.

    1985-01-01

    The tube plug comprises a one piece mechanical plug having one open end and one closed end which is capable of being inserted in a heat exchange tube and internally expanded into contact with the inside surface of the heat exchange tube for preventing flow of a coolant through the heat exchange tube. The tube plug also comprises a groove extending around the outside circumference thereof which has an elastomeric material disposed in the groove for enhancing the seal between the tube plug and the tube

  1. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... any of these problems: a dislodged tube a blocked or clogged tube any signs of infection (including redness, swelling, or warmth at the tube site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site severe abdominal pain lasting ...

  2. Microfinance Non-Financial Services: A Key for Poverty Alleviation? Lessons from Mexico\\ud

    OpenAIRE

    Biosca, Olga; Lenton, Pamela; Mosley, Paul

    2011-01-01

    Microfinance non-financial services have been recently reformulated as high quality demand-led programs. In the Mexican context, these are now voluntary, can have a cost for the borrower and are frequently supplied in partnership with specialized public or private agencies. Using primary data from a survey of clients of two credit-plus programs in Chiapas, this paper examines and compares the participation determinants and added impact of the training sessions on monetary poverty outcomes of ...

  3. Microfinance Non-Financial Services: A Key for Poverty Alleviation? Lessons from Mexico

    OpenAIRE

    Olga Biosca; Pamela Lenton; Paul Mosley

    2011-01-01

    Microfinance non-financial services have been recently reformulated as high quality demand-led programs. In the Mexican context, these are now voluntary, can have a cost for the borrower and are frequently supplied in partnership with specialized public or private agencies. Using primary data from a survey of clients of two credit-plus programs in Chiapas, this paper examines and compares the participation determinants and added impact of the training sessions on monetary poverty outcomes of ...

  4. Commercial banks moving into microfinance: which market entry model works best?

    OpenAIRE

    Kielb, Rachel

    2008-01-01

    This study examines the performance of business models used by commercial banks to enter the microfinance industry. The purpose of the study was to provide a high level indication of whether there is a model or models that yield better success than others. To conduct the research, four commer cial market entry models were chosen, and analysis of secondary data from the MixMaket dataset was completed compare model performance. Results indicated based on the methodology that the “service compan...

  5. Discipline and Flexibility: A Behavioral Perspective on Product Design in Microfinance

    OpenAIRE

    Labie, Marc; Laureti, Carolina; Szafarz, Ariane

    2016-01-01

    The success of both microcredit and micro-savings products rests upon simplicity and standardization in order to stimulate client discipline. Meanwhile, these products lack flexibility. This paper attempts to make sense of behavioral product design in microfinance. We focus on the potential trade-offs between discipline and flexibility. While discipline devices encourage clients make payments duly on time, flexibility improves clients’ day-to-day money management and helps them cope with shoc...

  6. Types of financial institution and their supply of financial services: the case of microfinance in Europe

    OpenAIRE

    Sergio Lagoa; Abdul Suleman

    2014-01-01

    The profit-oriented financial sector has grown in importance and influence, leading some authors to talk about a financialised economy. The question we raise in this paper is what is the role of non-profit oriented financial institutions and public programmes in the microfinance segment. We conclude that in this market there is a large diversity of institutions and non-for profit organisations have a significant role. Our analysis also shows that the diversity of institutional forms is import...

  7. La microfinance en Afrique centrale: Le défi des exclus

    International Development Research Centre (IDRC) Digital Library (Canada)

    GOUVERNANCE ET PERFORMANCES DES INSTITUTIONS DE ... la Faculté des Sciences Économiques et de Gestion, Université de Yaoundé II – Soa, Cameroun. ..... De fait, dans la mesure où la microfinance favorise un lissage des revenus, ...... 10 n'avaient pas le contrôle de leur crédit et le remettaient soit à leur mari, ...

  8. Integrating microfinance and health strategies: examining the evidence to inform policy and practice.

    Science.gov (United States)

    Leatherman, Sheila; Metcalfe, Marcia; Geissler, Kimberley; Dunford, Christopher

    2012-03-01

    Single solutions continue to be inadequate in confronting the prevalent problems of poverty, ill health and insufficient health system capacity worldwide. The poor need access to an integrated set of financial and health services to have income security and better health. Over 3500 microfinance institutions (MFIs) provide microcredit and financial services to more than 155 million households worldwide. Conservative estimates indicate that at least 34 million of these households are very poor by the definition in the Millennium Development Goals, representing around 170 million people, many in remote areas beyond the reach of health agencies, both private and governmental. A small but increasing number of MFIs offer health-related services, such as education, clinical care, community health workers, health-financing and linkages to public and private health providers. Multiple studies indicate the effectiveness of microfinance and its impact on poverty. A small but growing number of studies also attempt to show that MFIs are capable of contributing to health improvement by increasing knowledge that leads to behavioural changes, and by enhancing access to health services through addressing financial, geographic and other barriers. While these studies are of uneven quality, they indicate positive health benefits in diverse areas such as maternal and child health, malaria and other infectious disease, and domestic violence. While more rigorous research is needed to inform policy and guide programme implementation to integrate microfinance and health interventions that can reliably enhance the well-being of the poor, there is useful evidence to support the design and delivery of integrated programmes now. Worldwide, current public health programmes and health systems are proving to be inadequate to meet population needs. The microfinance sector offers an underutilized opportunity for delivery of health-related services to many hard-to-reach populations.

  9. Measurement of gas-liquid two-phase flow around horizontal tube bundle using SF6-water. Simulating high-pressure high-temperature gas-liquid two-phase flow of PWR/SG secondary coolant side at normal pressure

    International Nuclear Information System (INIS)

    Ishikawa, Atsushi; Imai, Ryoj; Tanaka, Takahiro

    2014-01-01

    In order to improve prediction accuracy of analysis code used for design and development of industrial products, technology had been developed to create and evaluate constitutive equation incorporated in analysis code. The experimental facility for PWR/SG U tubes part was manufactured to measure local void fraction and gas-liquid interfacial velocity with forming gas-liquid upward two-phase flow simulating high-pressure high-temperature secondary coolant (water-steam) rising vertically around horizontal tube bundle. The experimental facility could reproduce flow field having gas-liquid density ratio equivalent to real system with no heating using SF6 (Sulfur Hexafluoride) gas at normal temperature and pressure less than 1 MPa, because gas-liquid density ratio, surface tension and gas-liquid viscosity ratio were important parameters to determine state of gas-liquid two-phase flow and gas-liquid density ratio was most influential. Void fraction was measured by two different methods of bi-optical probe and conductivity type probe. Test results of gas-liquid interfacial velocity vs. apparent velocity were in good agreement with existing empirical equation within 10% error, which could confirm integrity of experimental facility and appropriateness of measuring method so as to set up original constitutive equation in the future. (T. Tanaka)

  10. Human Resource Management Practices and Employee Satisfaction in Microfinance Banks in Nigeria

    Directory of Open Access Journals (Sweden)

    Chijioke Esogwa Nwachukwu

    2017-06-01

    Full Text Available Purpose of the article: The role of microfinance banks (MFBs in the growth and development of businesses in an emerging market such as Nigeria cannot be overemphasised. Implementing sound human resource practices can enable MFBs satisfy their employees and sustain competitive advantage. Methodology/methods: A purposive sample of 60 senior employees of 10 microfinance banks in Nigeria was used for this study. All the 60 questionnaires were returned but 59 were found usable for the analysis, accounting for 98.3% response rate. In analyzing our data, Pearson correlation, ANOVA, and multiple regression techniques were used. Scientific aim: The goal of this study is to investigate HRM practices and employee satisfaction in microfinance banks in Nigeria. Findings: The result shows that a significant positive association exists between human resource planning, training and development, employee compensation and employee satisfaction. However, an insignificant positive relationship exists between work environment and employee satisfaction. Only three out of the four hypotheses are supported. Conclusions: HRM practices are tools used by organisations to get the best out of their workers, thus, achieve superior business performance. The authors, therefore, recommend that organizations that want to remain competitive must ensure that various stakeholders are satisfied (including employees by implementing a robust HRM practices.

  11. Microfinance and the Decision to Invest in Children’s Education

    Directory of Open Access Journals (Sweden)

    PV Viswanath

    2018-02-01

    Full Text Available Although one of the primary objectives of microfinance has been the reduction of poverty through the provision of credit for income-generating purposes, evidence of its impact on poverty has been mixed. Even if there is no direct impact of microfinance, there may be an indirect positive impact through the effect of microcredit availability on families’ decisions to invest in their children’s education. In this paper, I describe a study undertaken to gauge the impact of microcredit availability on education expenditures for children of clients of a South Indian microfinance institution. I first look at some determinants of the demand for education and then go on to consider what we know about how microcredit affects this demand. I find that microcredit has an impact on the demand for education as mediated by wealth effects and status effects, i.e., microloans increase spending on education the greater the wealth and the greater the social status of the family. Focus group interviews suggest that the impact of microcredit on the demand for education comes mainly from the greater access to financial resources and, to a lesser degree, from an accompanying appreciation of the value of education.

  12. Microfinance Institutions’ Social Intermediation and Micro and Small Enterprises Survival in Thika Town, Kenya

    Directory of Open Access Journals (Sweden)

    ZabronChege Wairimu

    2017-05-01

    Full Text Available The continuous rapid growth of microfinance institutions in Kenya seems not to offer enough solution to the micro and small enterprises survival challenges with more than a one-third of MSEs start-ups collapsing within the first three years. It is the high rate of collapse and low rate of survival of MSEs that motivated this research to fill the existing gap on the missing linkage between MFIs and MSEs survival. This study looked at the role of the social intermediation services offered by MFIs on survival of MSEs in Thika Town which is both an industrial town and a business hub. A descriptive study design was adopted. Stratified and purposive sampling methods were used to select a sample 272 MSEs. Findings indicated that; regular microfinance participation help reduce loan application and payment bureaucracy while keeping entrepreneur updated on available opportunities. Training equips MSEs owners with necessary managerial skills on financial management, book keeping, and business operations. Group liability eliminates the need for collateral security when accessing loan while it increases the amount of loan accessed. Networking increases business link widening goods and services markets and allows for formation of business clubs. Finally, it was found that training was the most sought service followed by group liability, microfinance participation, and networking. From the study findings, the researcher recommends that MSEs continue seeking for social intermediation services and especially networking to improve their competitiveness and create a competitive advantage over their competitors boosting their survival.

  13. DEVELOPMENT OF COILED TUBING STRESS ANALYSIS

    Directory of Open Access Journals (Sweden)

    Davorin Matanović

    1998-12-01

    Full Text Available The use of coiled tubing is increasing rapidly with drilling of horizontal wells. To satisfy all requirements (larger mechanical stresses, larger fluid capacities the production of larger sizes and better material qualities was developed. Stresses due to axial forces and pressures that coiled tubing is subjected are close to its performance limits. So it is really important to know and understand the behaviour of coiled tubing to avoid its break, burst or collapse in the well.

  14. Interactions between microfinance programmes and non-economic empowerment of women associated with intimate partner violence in Bangladesh: a cross-sectional study

    Science.gov (United States)

    Dalal, Koustuv; Dahlström, Örjan; Timpka, Toomas

    2013-01-01

    Objective This study aims to examine the associations between microfinance programme membership and intimate partner violence (IPV) in different socioeconomic strata of a nationally representative sample of women in Bangladesh. Methods The cross-sectional study was based on a nationally representative interview survey of 11 178 ever-married women of reproductive age (15–49 years). A total of 4465 women who answered the IPV-related questions were analysed separately using χ2 tests and Cramer's V as a measure of effect size to identify the differences in proportions of exposure to IPV with regard to microfinance programme membership, and demographic variables and interactions between microfinance programme membership and factors related to non-economic empowerment were considered. Results Only 39% of women were members of microfinance programmes. The prevalence of a history of IPV was 48% for moderate physical violence, 16% for severe physical violence and 16% for sexual violence. For women with secondary or higher education, and women at the two wealthiest levels of the wealth index, microfinance programme membership increased the exposure to IPV two and three times, respectively. The least educated and poorest groups showed no change in exposure to IPV associated with microfinance programmes. The educated women who were more equal with their spouses in their family relationships by participating in decision-making increased their exposure to IPV by membership in microfinance programmes. Conclusions Microfinance plans are associated with an increased exposure to IPV among educated and empowered women in Bangladesh. Microfinance firms should consider providing information about the associations between microfinance and IPV to the women belonging to the risk groups. PMID:24319278

  15. Managing Operational Risk Related to Microfinance Lending Process using Fuzzy Inference System based on the FMEA Method: Moroccan Case Study

    Directory of Open Access Journals (Sweden)

    Alaoui Youssef Lamrani

    2017-12-01

    Full Text Available Managing operational risk efficiently is a critical factor of microfinance institutions (MFIs to get a financial and social return. The purpose of this paper is to identify, assess and prioritize the root causes of failure within the microfinance lending process (MLP especially in Moroccan microfinance institutions. Considering the limitation of traditional failure mode and effect analysis (FMEA method in assessing and classifying risks, the methodology adopted in this study focuses on developing a fuzzy logic inference system (FLIS based on (FMEA. This approach can take into account the subjectivity of risk indicators and the insufficiency of statistical data. The results show that the Moroccan MFIs need to focus more on customer relationship management and give more importance to their staff training, to clients screening as well as to their business analysis.

  16. Evaporation of new refrigerants on tubes with improved surfaces; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree

    Energy Technology Data Exchange (ETDEWEB)

    Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

    1995-07-15

    The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-404A, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microfin heat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) 28 figs., 25 refs.

  17. Effect of tube-support interaction on the dynamic responses of heat exchanger tubes

    International Nuclear Information System (INIS)

    Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

    1977-01-01

    Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports

  18. Vertical and horizontal subsidiarity

    Directory of Open Access Journals (Sweden)

    Ivan V. Daniluk

    2016-02-01

    Full Text Available This article makes an attempt to analyze the principle of subsidiarity in its two main manifestations, namely vertical and horizontal, to outline the principles of relations between the state and regions within the vertical subsidiarity, and features a collaboration of the government and civil society within the horizontal subsidiarity. Scientists identify two types, or two levels of the subsidiarity principle: vertical subsidiarity and horizontal subsidiarity. First, vertical subsidiarity (or territorial concerning relations between the state and other levels of subnational government, such as regions and local authorities; second, horizontal subsidiarity (or functional concerns the relationship between state and citizen (and civil society. Vertical subsidiarity expressed in the context of the distribution of administrative responsibilities to the appropriate higher level lower levels relative to the state structure, ie giving more powers to local government. However, state intervention has subsidiary-lower action against local authorities in cases of insolvency last cope on their own, ie higher organisms intervene only if the duties are less authority is insufficient to achieve the goals. Horizontal subsidiarity is within the relationship between power and freedom, and is based on the assumption that the concern for the common good and the needs of common interest community, able to solve community members (as individuals and citizens’ associations and role of government, in accordance horizontal subsidiarity comes to attracting features subsidiarity assistance, programming, coordination and possibly control.

  19. Prediction of Heat Removal Capacity of Horizontal Condensation Heat Exchanger submerged in Pool

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Su; Hong, Soon-Joon [FNC Tech., Yongin (Korea, Republic of); Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of); Park, Goon-Cherl [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    As representative passive safety systems, there are the passive containment cooling system (PCCS) of ESBWR, the emergency condenser system (ECS) of the SWR-1000, the passive auxiliary feed-water system (PAFS) of the APR+ and etc. During the nuclear power plant accidents, these passive safety systems can cool the nuclear system effectively via the heat transfer through the steam condensation, and then mitigate the accidents. For the optimum design and the safety analysis of the passive safety system, it is essential to predict the heat removal capacity of the heat exchanger well. The heat removal capacity of the horizontal condensation heat exchanger submerged in a pool is determined by a combination of a horizontal in-tube condensation heat transfer and a boiling heat transfer on the horizontal tube. Since most correlations proposed in the previous nuclear engineering field were developed for the vertical tube, there is a certain limit to apply these correlations to the horizontal tube. Therefore, this study developed the heat transfer model for the horizontal Ushaped condensation heat exchanger submerged in a pool to predict well the horizontal in-tube condensation heat transfer, the boiling heat transfer on the horizontal tube and the overall heat removal capacity of the heat exchanger using the best-estimate system analysis code, MARS.

  20. From Credit to Collective Action: The Role of Microfinance in Promoting Women's Social Capital and Normative Influence

    Science.gov (United States)

    Sanyal, Paromita

    2009-01-01

    Can economic ties positively influence social relations and actions? If so, how does this influence operate? Microfinance programs, which provide credit through a group-based lending strategy, provide the ideal setting for exploring these questions. This article examines whether structuring socially isolated women into peer-groups for an…

  1. The Development of Psychological Capacity for Action : The Empowering Effect of a Microfinance Programme on Women in Sri Lanka

    NARCIS (Netherlands)

    Hansen, Nina

    This work examines the effect of a microfinance intervention on psychological empowerment among women in the North of Sri Lanka. Psychological empowerment is defined as personal (personal control beliefs) and social (social networks) capacity for action. The intervention included relevant skills

  2. The Poor Don’t Need Another Prophet: A People-Centered Approach to Microfinance and Education in Bolivia

    NARCIS (Netherlands)

    P.A. Arora (Payal)

    2006-01-01

    textabstractIntroduction: As international aid agencies increasingly embrace microfinance, the darling of international development, questions are beginning to surface. Who benefits from this savings and lending system that claims to target the poor? Does an increase in social capital of the poor

  3. Development Innovations through Entrepreneurial Microfinance and the Attempt to Achieve the United Nations Millennium Development Goals in Bangladesh

    Directory of Open Access Journals (Sweden)

    Saleh Ahmed

    2012-08-01

    Full Text Available As one of the countries in the Global South, Bangladesh has experienced numerous development challenges since its liberation in 1971. Bangladesh has showcased how to fight against poverty and to initiate meaningful change and development in human lives. Nobel Prize (2006 winner Grameen Bank is one of the popular development innovations in the country. Since the beginning of this Bank in the early 1970s, microfinance and entrepreneurship development with small amounts of money have proliferated to nearly every corner of the globe with the paramount goal of alleviating global poverty and ensuring human development. Like all other new social science techniques, the societal revolution brought about by microfinance expansion has left substantial room for refinement and further support by empirical evidence. This article critically evaluates a non-governmental initiative to empower extremely poor women through entrepreneurial microfinance, and examines the socioeconomic impacts in achieving the United Nations Millennium Development Goals (UNMDGs. This article covers both primary and secondary information. The aim is to demonstrate how countries of the Global South can use carefully designed microfinance projects to address major development challenges and meaningfully contribute to creating a more equal, humane society.

  4. Analysis of Third Party Loan Guarantee and Performance of Non-Prime Household Loans in Microfinance Banks in Kenya

    Directory of Open Access Journals (Sweden)

    Bernard Ndirangu Wachira

    2017-08-01

    Full Text Available Household loans remain the engine to productivity and economic growth globally. Non-prime household loan is essential, because it enables the borrowers with no collateral to access credit from Microfinance Banks. The survival and sustainability of non-prime household loans globally is therefore significant. Credit risk however remains the main deterrent of the soundness of Microfinance Banks. This leads to the poor performance of microfinance institutions in many economies in the world. Several countries globally are making inroad in reducing the credit risks, which lead to the poor performance of Microfinance Banks. It is still unknown why the credit risk affects the performance of non-prime household loans in the Microfinance Banks domiciled in Kenya. The reason for conducting this study is to determine the level at which the third party loan guarantee and the performance of non-prime household loans relate to the Microfinance Banks in Kenya. Particularly, this study is to determine how the amount secured by guarantee, recoveries from guarantors, percentage of loan secured, and percentage recoveries from guarantors relate to the performance of nonprime household loans in the Microfinance Banks in Kenya. The population was 516 senior management employees of the banks. The researcher conducted a multiple regression analysis for determining the relationship between the amount secured by guarantee—recoveries from guarantors, percentage granted, and percentage recoveries—and the performance of non-prime household loans. The R and R2 were used for determining the strength of the relationship and the coefficient of determination at 0.05 level of significance of variables. The result of this study reveals that there exists a strong relationship between the dependent and independent variables, thereby contradicting the null hypothesis, which states that the relationship does not exist. The percentage of the recoveries from the guarantors over the

  5. Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

    International Nuclear Information System (INIS)

    Bucholz, J.A.

    2000-01-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source

  6. Source Terms for HFIR Beam Tube Shielding Analyses, and a Complete Shielding Analysis of the HB-3 Tube

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    2000-07-01

    The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory is in the midst of a massive upgrade program to enhance experimental facilities. The reactor presently has four horizontal experimental beam tubes, all of which will be replaced or redesigned. The HB-2 beam tube will be enlarged to support more guide tubes, while the HB-4 beam tube will soon include a cold neutron source.

  7. Research on optimizing components of microfine high-performance composite cementitious materials

    International Nuclear Information System (INIS)

    Hu Shuguang; Guan Xuemao; Ding Qingjun

    2002-01-01

    The relationship between material components and mechanical properties was studied in terms of composite material principles and orthogonal experimental design. Moreover, the microstructure of microfine high-performance composite cementitious material (MHPCC) paste was investigated by means of scanning electron microscopy (SEM) methods. The results showed that the composite material consisting of blast furnace slag (BFS), gypsum (G 2 ) and expansive agent (EA) could obviously improve the strength of the cementitious material containing 40% fly ash (FA). Although microfine cement (MC) was merely 45% percent of the MHPCC, the compressive strength of MHPCC paste was higher than that of neat MC paste. BFS played an important role in MHPCC. The optimum-added quantity of BFS was 15%. The needle-shaped ettringite obtained from the EA reacting with Ca(OH) 2 forms a three-dimensional network structure, which not only improved the early strength of MHPCC paste but also increased its late strength. The reason was that the network structure, which was similar to a fiber-reinforced composite, was formed in the late period of hydration with the progress of hydration and the deposition of hydration products into the network structure

  8. Microfinance: Diagnosis of the micro-business, medium-sized business and its financial technology

    Directory of Open Access Journals (Sweden)

    Emerson Toledo Concha

    2009-12-01

    Full Text Available This research work shows how the financing for micro and small businesses in Peru has increased and has greatlyexpanded in the last few years, not only in institutions specialized in this field, focused their efforts in giving financialservices to businesspeople of micro and medium-sized business, but most of the so-called traditional banks havefocused their attention to this emerging sector using the know-how of microfinance lending technology, banking seekto work with people of low income sectors, that were not subject for credit opportunities to develop their business andas a consequence not able to improve their quality of life .Throughout this investigation, we make a diagnosis of macro and micro environment of the microfinance field, itsdevelopment and expectations for a strong presence in the Peruvian financial market. We consider the development oflending technology, where the analysis of the ability and willingness to pay are the fundamental basis for the evaluationof credits in specialized companies in this sector.

  9. Effect of doctoring on the performance of direct gravure printing for conductive microfine lines

    Science.gov (United States)

    Phuong Hoang, Huu; Lim Ko, Sung

    2015-11-01

    Printed electronics on flexible thin film has challenged and inspired the motivation of scientists in many fields. Among traditional printing methods such as stamping, flexography, offset, screen-printing, and inkjet, the gravure method is expected to reduce costs and increase productivity for printed electronics applications. In this research, conductive microfine line patterns, which print out the layer as microelectrodes for organic thin film transistor (OTFT) or microcircuit lines, have been designed with different size widths and lengths according to the printing direction, MD (machine direction), and CMD (cross machine direction, or transverse direction, TD, which is popularly used in industry). These patterns were printed with nano-particle silver ink on PI thin film, but had some serious problems with discontinuity and less filling after doctoring and printing. To solve these problems, the doctoring effect is investigated and analyzed before ink transferring, mainly in the printing machine direction and CMD. The uniformity and accuracy of the microfine lines are controlled and improved in order to achieve the stability of the printed pattern lines. In this work, considering the effect of the deflection of the doctor blade in the CMD (transverse direction), a doctoring model in the CMD is proposed and compared with the experimental result. Experimentally, proper doctoring conditions like blade stiffness and doctoring pressure are sought.

  10. Effect of doctoring on the performance of direct gravure printing for conductive microfine lines

    International Nuclear Information System (INIS)

    Hoang, Huu Phuong; Ko, Sung Lim

    2015-01-01

    Printed electronics on flexible thin film has challenged and inspired the motivation of scientists in many fields. Among traditional printing methods such as stamping, flexography, offset, screen-printing, and inkjet, the gravure method is expected to reduce costs and increase productivity for printed electronics applications. In this research, conductive microfine line patterns, which print out the layer as microelectrodes for organic thin film transistor (OTFT) or microcircuit lines, have been designed with different size widths and lengths according to the printing direction, MD (machine direction), and CMD (cross machine direction, or transverse direction, TD, which is popularly used in industry). These patterns were printed with nano-particle silver ink on PI thin film, but had some serious problems with discontinuity and less filling after doctoring and printing. To solve these problems, the doctoring effect is investigated and analyzed before ink transferring, mainly in the printing machine direction and CMD. The uniformity and accuracy of the microfine lines are controlled and improved in order to achieve the stability of the printed pattern lines. In this work, considering the effect of the deflection of the doctor blade in the CMD (transverse direction), a doctoring model in the CMD is proposed and compared with the experimental result. Experimentally, proper doctoring conditions like blade stiffness and doctoring pressure are sought. (paper)

  11. Synthesis of nanoparticle emulsion collector HNP and its application in microfine chalcopyrite flotation

    Science.gov (United States)

    He, G. C.; Ding, J.; Huang, C. H.; Kang, Q.

    2018-01-01

    Hydrophobic polystyrene nanoparticles bearing thiazole groups named HNP were used as collectors to improve recovery of microfine chalcopyrite in flotation. HNP adsorbs onto microfine particles selectively, which were modified hydrophobically to induce flotation effectively. Particle size and scanning electron microscope analysis for HNP show that HNP is a spherical nano particles with small size, uniform distribution and good dispersion. Infrared spectrum analysis for HNP proved that functional monomer 2-mercapto styrene acrylic thiazole was bonded chemically onto styrene. Flotation test results indicate that HNP is the right collector of chalcopyrite. Especially, the recovery of chalcopyrite is higher than 95% in neutral and acid media. FTIR results reveal that the flotation selectivity of collector HNP is due to strong chemical absorption onto chalcopyrite surface. Zeta potential analysis shows that the zeta potential of chalcopyrite decreased more quickly after interaction with HNP with the increase of pulp pH value, confirming that collector HNP is an anionic collector. Scanning electron microscope conform that HNP has good selective adsorption on chalcopyrite.

  12. SOCIAL ENTERPRISES AND MICROFINANCE AS TOOLS FOR POVERTY ALLEVIATION IN ROMANIA

    Directory of Open Access Journals (Sweden)

    OANA-MIRELA COJOCARU (DIACONESCU

    2016-12-01

    Full Text Available Poverty is a dangerous indicator that situates Romania in top positions in many EU statistics: 40% of the population is at risk of poverty or social exclusion and 29% have severe material deprivation. Even though it has been stated on several occasions that funds for the eradication of poverty in Romania do exist, the lack of interest and focus on solving this problem have led to the mismanagement of these funds. In contrast with the previous EU financing programme, a new perspective on the policy creation regarding poverty alleviation has been recently developed and is presented as an integrated package. This wishes to bring together disparate programmes/projects and different stakeholders. This proposal is a very different approach from institutional/methodological point of view, and it has been said to mark “the start of an effective capacity building effort”. The purpose of this literature exploration is focused on the potential Romanian social enterprises and microfinance have in poverty alleviation, taking into consideration that these tools have been created especially for poverty eradication. Our conclusion has been that policy makers have to sustain the development of social enterprises through microfinance, which most of the times can be the single financial instrument available to them.

  13. A Microfinance Program Targeting People Living with HIV in Uganda: Client Characteristics and Program Impact.

    Science.gov (United States)

    Linnemayr, Sebastian; Buzaalirwa, Lydia; Balya, James; Wagner, Glenn

    HIV has disproportionately affected economically vulnerable populations. HIV medical care, including antiretroviral therapy, successfully restores physical health but can be insufficient to achieve social and economic health. It may therefore be necessary to offer innovative economic support programs such as providing business training and microcredit tailored to people living with HIV/AIDS. However, microfinance institutions have shown reluctance to reach out to HIV-infected individuals, resulting in nongovernment and HIV care organizations providing these services. The authors investigate the baseline characteristics of a sample of medically stable clients in HIV care who are eligible for microcredit loans and evaluate their business and financial needs; the authors also analyze their repayment pattern and how their socioeconomic status changes after receipt of the program. The authors find that there is a significant unmet need for business capital for the sample under investigation, pointing toward the potentially beneficial role of providing microfinance and business training for clients in HIV care. HIV clients participating in the loans show high rates of repayment, and significant increases in (disposable) income, as well as profits and savings. The authors therefore encourage other HIV care providers to consider providing their clients with such loans.

  14. Education and microfinance: an alternative approach to the empowerment of the poor people in Indonesia.

    Science.gov (United States)

    Hadi, Rizali; Wahyudin, Uyu; Ardiwinata, Jajat S; Abdu, Wamaungo Juma

    2015-01-01

    There is good reason to combine education with microcredit for poverty alleviation in the poor communities of the developing world, including in Indonesia. Poverty is dangerous, it deprives people of their right to education, their right to good health, their right to freedom of speech, their right to democracy, their right to financial services and of course their right to knowledge enhancement, which are all crucial to living a better life. We must therefore, provide services beyond, credits for the poor. In this case, education should be included to each and every development agenda for the poor since it is key to any positive change and sustainable development of people. If well planned and well integrated within the microcredit services, education can serve a good purpose in poverty alleviation. This paper describes how education and microfinance have been used in combination to alleviate poverty in Indonesia, especially in the areas studied. The study uses a multi-cases approach to examine the purposively selected baitul maal tamwil (BMTs) organisations, which are sharia based semiformal microfinance institutions regarded to be among those few integrating education with their financial services.

  15. Horizontal violence in Nursing

    Directory of Open Access Journals (Sweden)

    Tsimoulaki Evangelia

    2017-01-01

    Full Text Available One’s effort to clarify the definition of horizontal labour violence is of great importance, due to the variety of definitions that are mentioned in the worldwide scientific literature. Furthermore, the reference of multiple forms of such violence herein the nurse professional group is challenging, as well. Another fact of great importance is that, any form of professional violence (horizontal violence, horizontal mobbing in the work place environment can be possibly escalated and include even physical abuse (Bullying, besides the psychological and emotional impact for the victim. The definitions of Horizontal violence, Mobbing and Bullying, include a repeated negative behaviour emanating from at least one “predator” towards at least one “victim”, with work status differences and the existence or lack of physical abuse (Bullying. Horizontal violence is a hostile, aggressive and harmful behaviour which is either overt or concealed and is pointed from an individual to another individual of the same working rank and causes intense emotional pain at the victim. The manifestations vary from humiliating tasks assignment or the victim’s efforts undermining to clearly aggressive behaviors (criticism, intimidation, sarcasm etc.. The reason behind this phenomenon is multifactorial extended not only towards the working environment but also to the personal characteristics of the “predator” as well as the possible “victim”. The researchers emphasize the high incidence of the phenomenon, as well as the cost that is induced by the violent behaviors to both the health professionals and the hospital. Finally, they point out the paradox of the presence of violence inside a system that is designed to promote health.

  16. Feeding Tubes

    Science.gov (United States)

    ... feeding therapies have been exhausted. Please review product brand and method of placement carefully with your physician ... Total Parenteral Nutrition. Resources: Oley Foundation Feeding Tube Awareness Foundation Children’s Medical Nutrition Alliance APFED’s Educational Webinar ...

  17. Analysis of Post Loan Disbursement Allocation and Performance of Non-Prime Household Loan in Microfinance Banks in Kenya

    Directory of Open Access Journals (Sweden)

    Bernard Ndirangu Wachira

    2017-08-01

    Full Text Available The part played by non-prime household loans in improving the lives of many people who cannot afford collateral globally cannot be ignored. Many Microfinance Banks in many economies worldwide have tried to maintain the Grameen Bank Model of granting microloans, mainly non-prime household loans. However, the credit risks associated with this initiative hamper the pace at which the granting of this credit facility is expected to grow. This study intends to explore the relationship between the post loan disbursement allocation and the performance of non-prime household loans in the Microfinance Banks in Kenya. The theory associated to this study is the Credit Risk Theory. This theory, which is regarded as credit structural theory, was developed by Merton in 1972. The descriptive survey research design method was applied, and the sample size was 150 respondents. The data-collection tool used was a questionnaire. A logistic regression analysis was conducted for the purpose of predicting non-prime household performance in the Microfinance Banks using training budget, recoveries budget, percentage of training budget, and percentage of recoveries budget as predictors. The Wald test shows that training budget, recoveries budget, and percentage of training budget were good predictors, making a significant contribution to prediction. The percentage of budget on recoveries was not a significant predictor. The Microfinance Banks should enhance the performance of non-prime household loans through capacity building to the borrowers and educate the borrowers on dangers of enforced loan recoveries. The government, through the Central Bank of Kenya, should have a training policy for the Microfinance Banks so that they can enlighten the borrowers on proper financial management to avoid conflicts with borrowers during loan recoveries.

  18. Coolant rate distribution in horizontal steam generator under natural circulation

    International Nuclear Information System (INIS)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A.

    1997-01-01

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered

  19. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A.; Leontieva, V.; Mitrioukhin, A. [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  20. Coolant rate distribution in horizontal steam generator under natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Blagovechtchenski, A; Leontieva, V; Mitrioukhin, A [St. Petersburg State Technical Univ. (Russian Federation)

    1998-12-31

    In the presentation the major factors determining the conditions of NCC (Natural Coolant Circulation) in the primary circuit and in particular conditions of coolant rate distribution on the horizontal tubes of PGV-1000 in NPP with VVER-1000 under NCC are considered. 5 refs.

  1. Apparatus for inspecting and repairing a pressurized-water reactor's steam generator heat exchanger tubes

    International Nuclear Information System (INIS)

    Mueller, O.; Roettger, H.; Kasti, H.; Hagen, H.G.

    1976-01-01

    Described is an apparatus provided for use with a pressurized-water reactor' steam generator having a manifold chamber enclosing the bottom side of a horizontal tube sheet having holes therethrough in which are mounted the tubes of a heat exchanger tube bundle. The manifold chamber has a manhole giving access to the tube's bottom side to permit internal inspection or repair of the tubes by registration of an end of a flexible guide conduit with the tube sheet holes and through which a flexible carrier can be guided for insertion via these holes in the tube sheet and through the tubes extending from the tube sheet's other side

  2. Steam generator tube extraction

    International Nuclear Information System (INIS)

    Delorme, H.

    1985-05-01

    To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

  3. Comparison of four microfinance markets from the point of view of the effectuation theory, complemented by proposed musketeer principle illustrating forces within village banks

    Directory of Open Access Journals (Sweden)

    Hes Tomáš

    2017-03-01

    Full Text Available Microfinance services are essential tools of formalization of shadow economics, leveraging immature entrepreneurship with external capital. Given the importance of shadow economics for the social balance of developing countries, the importance of an answer to a question of how microfinance entities come into existence, is rather essential. While decision-taking process leading to entrepreneurship were explained by the effectuation theory developed in the 90’, these explanations were not concerned with the logics of creation of microenterprises in neither developing countries nor microfinance village banks. While the abovementioned theories explain the nascence of companies in environment of developed markets, importance of a focus on emerging markets related to large share of human society of microfinance clientele is obvious. The study provides a development streak to the effectuation Theory, adding the musketeer principle to the five effectuation principles proposed by Sarasvathy. Furthermore, the hitherto not considered relationship between social capital and effectuation related concepts is another proposal of the paper focusing on description of the nature of microfinance clientele from the point of view of effectuation theory and social capital drawing a comparison of microfinance markets in four countries, Turkey, Sierra Leone, Indonesia and Afghanistan.

  4. Microfinance Impact on Socio-Economic Empowerment: A special Reference to Andhra Pradesh

    Directory of Open Access Journals (Sweden)

    V Vachya L

    2015-03-01

    Full Text Available The present study seeks to examine the role of microfinance and its impact on economic and social empowerment of women. There are great debates going on whether forming groups, membership for women, providing credit and imparting some business skills would change the social equations in the society or whether provision of credit may lead to pervasively entrenched political and economic relations among the genders. The proponents argue that providing credit, targeting women can prove to be a suitable mechanism in ameliorating poor women’s socio-economic conditions and thereby can alter the relations between gender and class. Undoubtedly, there have been significant advances in women empowerment in recent years and the concept and practice of SHG-based microfinance has now developed deep roots in many parts of the country. Impact assessment being rather limited so far, it is hard to measure and quantify the effect the Indian microfinance experience so far had on the poverty situation in rural India. The present study seeks to examine the process of women empowerment and changes in the economic status of SHG members in particular and rural women in general. For this study, multi-stage stratified proportionate random sampling technique was adopted for selecting the representative districts, mandals/talukas, villages and households. The primary data was collected from six villages in the three regions (Coastal Andhra, Rayalaseema and Telangana of Andhra Pradesh. Tabular and statistical analyses were applied for examining the data. Empirically acclaimed logistic regression model has been employed for analyzing significant impact of plausible socio-economic factors on women empowerment. The study found that the socio-economic indicators have changed. It also emerged that there has been an increase in women participation in the household decision making process. The study has suggested that the government should prepare suitable plans and programmes

  5. Relationship Between Employee Job Satisfaction and Turnover Intention in Microfinance Banks in Pakistan

    Directory of Open Access Journals (Sweden)

    Saghir Ahmed

    2015-12-01

    Full Text Available This study is conducted to analyse the factors, which significantly affect employee job satisfaction in Microfinance Banks of Pakistan. Furthermore, the impact of employee job satisfaction is evaluated on employee turnover intentions. Reward system and training opportunities are taken as independent variables. Primary data is used for this research, which was collected through questionnaire and the reliability of instrument is checked using Cronbach’s alpha. Statistical Package for Social Sciences (SPSS is used to process the collected data. Descriptive statistics are determined and correlation among variables is also calculated. OLS method is applied to find out the impact of independent variables and the results show that there is a significant positive correlation among training, reward system and employee job satisfaction, while a negative relationship is found between employee job satisfaction and employee turnover intention.

  6. CONTRIBUTIONS OF MICROFINANCE INSTITUTIONS TO ECONOMIC EFFICIENCY OF CASSAVA FARMERS IN ABIA STATE, NIGERIA

    Directory of Open Access Journals (Sweden)

    Kingsley Chukwuemeka OBIKE

    2014-10-01

    Full Text Available The study examined contributions of microfinance institutions to economic efficiency of cassava farmers in Abia state, Nigeria. A multistage random sampling technique was adopted in collecting cross sectional data on a sample size of 240 respondents (120 MFI beneficiaries and 120 non beneficiaries. Primary Data was collected by administering questionnaire on cassava farmers. The result showed that economic efficiency of MFI beneficiaries was influenced by wage rate, price of fertilizer and adjusted Y (output, while wage rate, price of fertilizer and price of cassava cutting s are variables that influenced economic efficiency of non beneficiaries. The t – test analysis confirmed that MFI beneficiaries had higher economic efficiency advantage compared with non beneficiaries. It is recommended that government agricultural policy should take positive steps to reduce interest rate to encourage MFI efforts in providing the necessary platform to encourage higher efficiency in cassava production in Abia state, Nigeria.

  7. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

  8. Effect of Tube Pitch on Pool Boiling Heat Transfer of Vertical Tube Bundle

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2016-01-01

    Summarizing the previous results it can be stated that heat transfer coefficients are highly dependent on the tube pitch and the heat flux of the relevant tube. The published results are mostly about the horizontal tubes. However, there are many heat exchangers consisting of vertical tubes like AP600. Therefore, the focus of the present study is an identification of the effects of a tube pitch as well as the heat flux of a relevant tube on the heat transfer of a tube bundle installed vertically. When the heat flux is increased many bubbles are generating due to the increase of the nucleation sites. The bubbles become coalescing with the nearby bubbles and generates big bunches of bubbles on the tube surface. This prevents the access of the liquid to the surface and deteriorates heat transfer. The bubble coalescence is competing with the mechanisms enhancing heat transfer. The pitch was varied from 28.5 mm to 95 mm and the heat flux of the nearby tube was changed from 0 to 90kW/m"2. The enhancement of the heat transfer is clearly observed when the heat flux of the nearby tube becomes larger and the heat flux of the upper tube is less than 40kW/m"2. The effect of the tube pitch on heat transfer is negligible as the value of DP/ is increased more than 4.

  9. A combined microfinance and training intervention can reduce HIV risk behaviour in young female participants.

    Science.gov (United States)

    Pronyk, Paul M; Kim, Julia C; Abramsky, Tanya; Phetla, Godfrey; Hargreaves, James R; Morison, Linda A; Watts, Charlotte; Busza, Joanna; Porter, John Dh

    2008-08-20

    To assess effects of a combined microfinance and training intervention on HIV risk behavior among young female participants in rural South Africa. : Secondary analysis of quantitative and qualitative data from a cluster randomized trial, the Intervention with Microfinance for AIDS and Gender Equity study. Eight villages were pair-matched and randomly allocated to receive the intervention. At baseline and after 2 years, HIV risk behavior was assessed among female participants aged 14-35 years. Their responses were compared with women of the same age and poverty group from control villages. Intervention effects were calculated using adjusted risk ratios employing village level summaries. Qualitative data collected during the study explored participants' responses to the intervention including HIV risk behavior. After 2 years of follow-up, when compared with controls, young participants had higher levels of HIV-related communication (adjusted risk ratio 1.46, 95% confidence interval 1.01-2.12), were more likely to have accessed voluntary counseling and testing (adjusted risk ratio 1.64, 95% confidence interval 1.06-2.56), and less likely to have had unprotected sex at last intercourse with a nonspousal partner (adjusted risk ratio 0.76, 95% confidence interval 0.60-0.96). Qualitative data suggest a greater acceptance of intrahousehold communication about HIV and sexuality. Although women noted challenges associated with acceptance of condoms by men, increased confidence and skills associated with participation in the intervention supported their introduction in sexual relationships. In addition to impacts on economic well being, women's empowerment and intimate partner violence, interventions addressing the economic and social vulnerability of women may contribute to reductions in HIV risk behavior.

  10. Application of the Critical Heat Flux Look-Up Table to Large Diameter Tubes

    Directory of Open Access Journals (Sweden)

    M. El Nakla

    2013-01-01

    Full Text Available The critical heat flux look-up table was applied to a large diameter tube, namely 67 mm inside diameter tube, to predict the occurrence of the phenomenon for both vertical and horizontal uniformly heated tubes. Water was considered as coolant. For the vertical tube, a diameter correction factor was directly applied to the 1995 critical heat flux look-up table. To predict the occurrence of critical heat flux in horizontal tube, an extra correction factor to account for flow stratification was applied. Both derived tables were used to predict the effect of high heat flux and tube blockage on critical heat flux occurrence in boiler tubes. Moreover, the horizontal tube look-up table was used to predict the safety limits of the operation of boiler for 50% allowable heat flux.

  11. Horizontal wells in subsurface remediation

    International Nuclear Information System (INIS)

    Losonsky, G.; Beljin, M.S.

    1992-01-01

    This paper reports on horizontal wells which offer an effective alternative to vertical wells in various environmental remediation technologies. Hydrogeological advantages of horizontal wells over vertical wells include a larger zone of influence, greater screen length, higher specific capacity and lower groundwater screen entrance velocity. Because of these advantages, horizontal wells can reduce treatment time and costs of groundwater recovery (pump-and-treat), in situ groundwater aeration (sparging) and soil gas extraction (vacuum extraction). Horizontal wells are also more effective than vertical wells in landfill leachate collection (under-drains), bioremediation, and horizontal grout injection

  12. Acceptability of a microfinance-based empowerment intervention for transgender and cisgender women sex workers in Greater Kuala Lumpur, Malaysia

    Science.gov (United States)

    Lall, Priya; Shaw, Stacey A.; Saifi, Rumana; Sherman, Susan G.; Azmi, Nuruljannah Nor; Pillai, Veena; El-Bassel, Nabila; Kamarulzaman, Adeeba; Wickersham, Jeffrey A.

    2017-01-01

    Abstract Introduction: Cisgender and transgender woman sex workers (CWSWs and TWSWs, respectively) are key populations in Malaysia with higher HIV-prevalence than that of the general population. Given the impact economic instability can have on HIV transmission in these populations, novel HIV prevention interventions that reduce poverty may reduce HIV incidence and improve linkage and retention to care for those already living with HIV. We examine the feasibility of a microfinance-based HIV prevention intervention among CWSW and TWSWs in Greater Kuala Lumpur, Malaysia. Methods: We conducted 35 in-depth interviews to examine the acceptability of a microfinance-based HIV prevention intervention, focusing on: (1) participants’ readiness to engage in other occupations and the types of jobs in which they were interested in; (2) their level of interest in the components of the potential intervention, including training on financial literacy and vocational education; and (3) possible barriers and facilitators to the successful completion of the intervention. Using grounded theory as a framework of analysis, transcripts were analysed through Nvivo 11. Results: Participants were on average 41 years old, slightly less than half (48%) were married, and more than half (52%) identified as Muslim. Participants express high motivation to seek employment in other professions as they perceived sex work as not a “proper job” with opportunities for career growth but rather as a short-term option offering an unstable form of income. Participants wanted to develop their own small enterprise. Most participants expressed a high level of interest in microfinance intervention and training to enable them to enter a new profession. Possible barriers to intervention participation included time, stigma, and a lack of resources. Conclusion: Findings indicate that a microfinance intervention is acceptable and desirable for CWSWs and TWSWs in urban Malaysian contexts as participants

  13. Acceptability of a microfinance-based empowerment intervention for transgender and cisgender women sex workers in Greater Kuala Lumpur, Malaysia.

    Science.gov (United States)

    Lall, Priya; Shaw, Stacey A; Saifi, Rumana; Sherman, Susan; Azmi, Nuruljannah Nor; Pillai, Veena; El-Bassel, Nabila; Kamarulzaman, Adeeba; Wickersham, Jeffrey A

    2017-08-02

    Cisgender and transgender woman sex workers (CWSWs and TWSWs, respectively) are key populations in Malaysia with higher HIV-prevalence than that of the general population. Given the impact economic instability can have on HIV transmission in these populations, novel HIV prevention interventions that reduce poverty may reduce HIV incidence and improve linkage and retention to care for those already living with HIV. We examine the feasibility of a microfinance-based HIV prevention intervention among CWSW and TWSWs in Greater Kuala Lumpur, Malaysia. We conducted 35 in-depth interviews to examine the acceptability of a microfinance-based HIV prevention intervention, focusing on: (1) participants' readiness to engage in other occupations and the types of jobs in which they were interested in; (2) their level of interest in the components of the potential intervention, including training on financial literacy and vocational education; and (3) possible barriers and facilitators to the successful completion of the intervention. Using grounded theory as a framework of analysis, transcripts were analysed through Nvivo 11. Participants were on average 41 years old, slightly less than half (48%) were married, and more than half (52%) identified as Muslim. Participants express high motivation to seek employment in other professions as they perceived sex work as not a "proper job" with opportunities for career growth but rather as a short-term option offering an unstable form of income. Participants wanted to develop their own small enterprise. Most participants expressed a high level of interest in microfinance intervention and training to enable them to enter a new profession. Possible barriers to intervention participation included time, stigma, and a lack of resources. Findings indicate that a microfinance intervention is acceptable and desirable for CWSWs and TWSWs in urban Malaysian contexts as participants reported that they were ready to engage in alternative forms of

  14. Electron tube

    Science.gov (United States)

    Suyama, Motohiro [Hamamatsu, JP; Fukasawa, Atsuhito [Hamamatsu, JP; Arisaka, Katsushi [Los Angeles, CA; Wang, Hanguo [North Hills, CA

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  15. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...

  16. Transduced for determining if steam generator tubes are locked in at support plate

    International Nuclear Information System (INIS)

    Hayes, J.K.

    1984-01-01

    A nuclear steam generator is described which includes a vessel, means to introduce vaporizable fluid into the bottom portion of the vessel, an outlet near the top through which vapor is discharged, a horizontal tube sheet extending across the vessel, a plurality of U-shaped tubes, having each end secured to and extending through the tube sheet, means for introducing heating fluid to one end of each of the U-shaped tubes, means for removing heating fluid from the other end of each of the U-shaped tubes, tube support means positioned within the vessel for preventing tube vibration, the tube support means including horizontally positioned means closely surrounding, but slightly spaced from each tube, means through which access can be had to the vessel interior beneath the tube sheet when the steam generator is not in operation, and testing means for determining whether or not a tube is locked into a tube support means including a longitudinal member, with a first end located inside the tube to be tested, and a second end located outside of the tube, means for securing the first end of the member to the inside of the tube, means for heating a length of the longitudinal member, and an equal length of the tube, to an elevated temperature, and means for indicating movement of the second end of the longitudinal member away from the tube end, which would indicate that the tube is locked into the support means

  17. Chest tube insertion

    Science.gov (United States)

    Chest drainage tube insertion; Insertion of tube into chest; Tube thoracostomy; Pericardial drain ... Be careful there are no kinks in your tube. The drainage system should always sit upright and be placed ...

  18. Enhanced Condensation Heat Transfer

    Science.gov (United States)

    Rose, John Winston

    The paper gives some personal observations on various aspects of enhanced condensation heat transfer. The topics discussed are external condensation (horizontal low-finned tubes and wire-wrapped tubes), internal condensation (microfin tubes and microchannels) and Marangoni condensation of binary mixtures.

  19. Analytical solution of velocity for ammonia-water horizontal falling-film flow

    International Nuclear Information System (INIS)

    Zhang, Qiang; Gao, Yide

    2016-01-01

    Highlights: • We built a new falling-film flow model that analyzed the film flow characteristics. • We have obtained a new formula of film thickness over the horizontal tube. • We derived analysis solution to analyze the effect of inertial force to velocity in the entrance region of liquid film. • It described the characters of the ammonia-waterfalling-film film over the horizontal tube. • It is good for falling-film absorption, generation and evaporation to optimizing the design parameters and further improving the capabilities. - Abstract: A new horizontal tube falling film velocity model was built and calculated to analyze the problem of film flow conditions. This model also analyzed the film thickness distribution in horizontal tube falling film flow and considered the effect of the inertial force on velocity. The film thickness and velocity profile can be obtained based on the principle of linear superposition, a method of separation of variables that introduces the effect of variable inertial force on the velocity profile in the process of falling-film absorption. The film flow condition and the film thickness distribution at different fluid Reynolds numbers (Re) and tube diameters were calculated and compared with the results of the Crank–Nicolson numerical solution under the same conditions. The results show that the film flow condition out of a horizontal tube and that the film thickness increases with the fluid Re. At a specific Re and suitable tube diameter, the horizontal tube reaches a more uniform film. Finally, the analysis results have similar trend with the experimental and numerical predicted data in literature.

  20. Franchising Microfinance

    OpenAIRE

    Amit Bubna; Bhagwan Chowdhry

    2010-01-01

    Financial intermediaries worldwide are seeking mechanisms for participating in micro lending. Using informed "local capitalists" as bank's on-lenders fails due to borrowers' incentive to default with multiple credit sources. A coalition of local capitalists may not resolve the problem in the presence of a monopoly moneylender with superior skills in lending and enforcement. A credible competitive threat to the moneylender can only arise if the local capitalist coalition also provides informat...

  1. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  2. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  3. Almost horizontal turbulence

    International Nuclear Information System (INIS)

    Kolmogorov, A N

    2004-01-01

    The paper is published without modifications. Kolmogorov's manuscript was apparently prepared during his participation in one of expeditions of the ship 'D. Mendeleev' to the Atlantic Ocean (1969) or in a circumnavigation of the world (1971) organized by the Institute for Oceanology led at the time by A.S. Monin. As Kolmogorov himself wrote, the choice of the topic was stimulated by observations concerning '...meanders with horizontal sizes of hundreds of kilometers on a flow involving a layer of hundreds of meters, with subsequent disintegration of these meanders into vortices gradually decreasing in size to several kilometers'. In modern terminology, the paper is devoted to the problem of intensive mixing in pycnoclines, that is, thin layers of stratified fluid, caused by internal waves whose frequencies are less than the Brent-Vaeisaelae frequency. Here I would like to note two circumstances. The first is the scientific insight characteristic for Kolmogorov; this very approach was later reflected in numerous publications (see, for instance, the monograph by V.S. Modevich, V.I. Nikulin, and A.G. Stetsenko 'Dynamics of internal mixing in a stratified medium', Institute for Hydromechanics, Academy of Sciences of Ukraine, Naukova Dumka, Kiev 1988). The second, the more significant in my opinion, is the genuine intellectual curiosity and breadth of thought of this great thinker, who studied not only the most abstract mathematical constructions but also got his head out of the clouds with great interest to solve concrete applied problems

  4. A horizontal dilution refrigerator for polarized target

    International Nuclear Information System (INIS)

    Isagawa, S.; Ishimoto, S.; Masaike, A.; Morimoto, K.

    1978-01-01

    A horizontal dilution refrigerator was constructed with a view to the spin frozen target and the deuteron polarized target. High cooling power at high temperature such as 3.7 mW at 400 mK serves for overcoming a heat load of microwave to polarize the nuclear spins in the target material. The cooling power at 50 mK was 50 μW, which is sufficient to hold the high nuclear polarization for long time. The lowest temperature reached was 26 mK. The refrigerator has rather simple heat exchangers, a long stainless steel double tube heat exchanger and two coaxial type heat exchangers with sintered copper. The mixing chamber is made of polytetrafluoroethylene (TFE) and demountable so that the target material can be easily put into it. (Auth.)

  5. ISLAMIC MICROFINANCE AND POVERTY ALLEVIATION PROGRAM: PRELIMINARY RESEARCH FINDINGS FROM INDONESIA

    Directory of Open Access Journals (Sweden)

    Yasushi Suzuki

    2016-06-01

    Full Text Available Poverty should be defined, measured, and scrutinized its root causes from a multi-dimension perspectives. Therefore, in designing and implementation of poverty alleviation program, it should consider economic factors, social and political contexts surrounding the poor. Sen (1982; 1999 views poverty as a multifaceted world and ethical dimension essentially should be placed underpinning it as a vital economic problem. The paper takes the stance that the poor themselves have potential capacity to alleviate their condition in resolving poverty trap. Community development program is one of the strategies to deal with the poverty problem. Islamic microfinance can play an important role in combating poverty dilemma especially in Muslim majority population communities. Through the approach proposed by Bigg and Satterthwaite (2005 with strengthening local organizations and community development programs, Islamic microfinance should engage a strategic partnership with the Masjid and Islamic charity institutions (zakat and waqf organization. This strategic alliance will result more integrated programs and also capacity building of the institutions involved. This paper aims to contribute a grass root model in the purpose of combating poverty in the framework of Islamic economic system. =========================================== Kemiskinan harus didefinisikan, diukur, dan diteliti akar penyebabnya dari berbagai perspektif. Oleh karena itu, dalam merancang dan mengimplementasikan program pengentasan kemiskinan, faktor-faktor ekonomi, konteks sosial dan politik yang mengelilingi kemiskinan juga harus dipertimbangkan. Sen (1982; 1999 memandang kemiskinan sebagai sebuah dunia yang kompleks, dan dimensi dasar etika harus ditempatkan sebagai sebuah masalah ekonomi yang vital. Peneliti sendiri dalam hal ini berpandangan bahwa orang-orang miskin pada dasarnya punya kapasitas yang memadai untuk keluar dari garis kemiskinan. Salah satunya adalah dengan program

  6. A systematic review of income generation interventions, including microfinance and vocational skills training, for HIV prevention.

    Science.gov (United States)

    Kennedy, Caitlin E; Fonner, Virginia A; O'Reilly, Kevin R; Sweat, Michael D

    2014-01-01

    Income generation interventions, such as microfinance or vocational skills training, address structural factors associated with HIV risk. However, the effectiveness of these interventions on HIV-related outcomes in low- and middle-income countries has not been synthesized. The authors conducted a systematic review by searching electronic databases from 1990 to 2012, examining secondary references, and hand-searching key journals. Peer-reviewed studies were included in the analysis if they evaluated income generation interventions in low- or middle-income countries and provided pre-post or multi-arm measures on behavioral, psychological, social, care, or biological outcomes related to HIV prevention. Standardized forms were used to abstract study data in duplicate and study rigor was assessed. Of the 5218 unique citations identified, 12 studies met criteria for inclusion. Studies were geographically diverse, with six conducted in sub-Saharan Africa, three in South or Southeast Asia, and three in Latin America and the Caribbean. Target populations included adult women (N = 6), female sex workers/bar workers (N = 3), and youth/orphans (N = 3). All studies targeted females except two among youth/orphans. Study rigor was moderate, with two group-randomized trials and two individual-randomized trials. All interventions except three included some form of microfinance. Only a minority of studies found significant intervention effects on condom use, number of sexual partners, or other HIV-related behavioral outcomes; most studies showed no significant change, although some may have had inadequate statistical power. One trial showed a 55% reduction in intimate partner violence (adjusted risk ratio 0.45, 95% confidence interval 0.23-0.91). No studies measured incidence/prevalence of HIV or sexually transmitted infections among intervention recipients. The evidence that income generation interventions influence HIV-related behaviors and outcomes is inconclusive. However, these

  7. A systematic review of income generation interventions, including microfinance and vocational skills training, for HIV prevention

    Science.gov (United States)

    Kennedy, Caitlin E.; Fonner, Virginia A.; O'Reilly, Kevin R.; Sweat, Michael D.

    2013-01-01

    Income generation interventions, such as microfinance or vocational skills training, address structural factors associated with HIV risk. However, the effectiveness of these interventions on HIV-related outcomes in low- and middle-income countries has not been synthesized. We conducted a systematic review by searching electronic databases from 1990-2012, examining secondary references, and hand searching key journals. Peer-reviewed studies were included in the analysis if they evaluated income generation interventions in low- or middle-income countries and provided pre-post or multi-arm measures on behavioral, psychological, social, care or biological outcomes related to HIV prevention. Standardized forms were used to abstract study data in duplicate and study rigor was assessed. Of 5,218 unique citations identified, 12 studies met criteria for inclusion. Studies were geographically diverse, with 6 conducted in sub-Saharan Africa, 3 in South or Southeast Asia, and 3 in Latin America and the Caribbean. Target populations included adult women (N=6), female sex workers/bar workers (N=3), and youth/orphans (N=3). All studies targeted females except 2 among youth/orphans. Study rigor was moderate, with 2 group-randomized trials and 2 individual-randomized trials. All interventions except 3 included some form of microfinance. Only a minority of studies found significant intervention effects on condom use, number of sexual partners or other HIV-related behavioral outcomes; most studies showed no significant change, although some may have had inadequate statistical power. One trial showed a 55% reduction in intimate partner violence (adjusted risk ratio 0.45, 95% confidence interval 0.23-0.91). No studies measured incidence/prevalence of HIV or sexually transmitted infections among intervention recipients. The evidence that income generation interventions influence HIV-related behaviors and outcomes is inconclusive. However, these interventions may have important effects

  8. Energy-microfinance intervention for below poverty line households in India

    International Nuclear Information System (INIS)

    Rao, P. Sharath Chandra; Miller, Jeffrey B.; Wang, Young Doo; Byrne, John B.

    2009-01-01

    More than 72% of India's population resides in rural India and it also has a high concentration of people living under abject poverty. Of the total rural population 27.1-28.3% lives below the poverty line (BPL). A lack of energy-finance options is hampering the 'quality of life' of the BPL community. The members of this disadvantaged household which forms 27.1% and 23.6% of the India's rural and urban population has no ready access to mainstream finance or know-how of sustainable energy products nor do they have access to energy service providing agency. This lack of energy-finance options has provided the marginalized population little means to break the conventional energy paradigm and the corresponding poverty cycle. Considering the afore-mentioned problem we propose an energy-microfinance intervention or a model that encompasses two independent entities. One has an energy expertise and the other possesses finance management skills. Alternately, we also propose a special purpose entity that comprises of these two entities. This entity fosters different institutional, technical and financial engineering approaches to the provision of energy, finance and infrastructure services necessary for poverty alleviation.

  9. The Effect of Social Capital on Customer’s Repayment Rate at Islamic Microfinance Institution

    Directory of Open Access Journals (Sweden)

    Jaenal Effendi

    2016-07-01

    Full Text Available The potency of Micro and Small Enterprises (MSEs in Indonesia which is great, is not directly proportional to the ease of getting capital from formal financial institutions such as banks because it is not bankable. Meanwhile, microfinance institutions (MFIs that provide financing to the MSEs are currently thriving. This condition exposes the existence of factors that cause the MFIs continuesly providing financing to MSEs which are not bankable. This research aims to analyze the effect of social capital toward the repayment rate of Islamic MFIs’ customers. The methods used in this research was the logistic regression. The results showed variable relationship with BMT employees, relations with other customers, and Islamic recitation had positive and significant effect toward the repayment rate of the customer. While recommendations, membership status, and travel time from home to the BMT had negative and significant effect.  Variable outside the social capital indicator which is income rate had no significant effect.DOI: 10.15408/aiq.v8i2.2631

  10. Do African microfinance institutions need efficiency for financial stability and social outreach?

    Directory of Open Access Journals (Sweden)

    Md A.K. Azad

    2016-09-01

    Full Text Available Microfinance institutions (MFIs have the dual objective of providing social welfare and financial stability. We evaluated the financial efficiency of MFIs in sub-Saharan African countries by comparing their regional performances during the period 2004-2013. We addressed prevailing MFI heterogeneity by using the concept of "metafrontier". The results showed that on an average, more than half the MFIs showed a drop in productivity. The measure of how much one country gets closer to or further away from world frontier technology is commonly known as the TGC score. In world frontier technology, East and South Asian countries have taken the lead (TGC score 1.0048 while sub-Saharan African countries lag behind (TGC score 1.0020. Most East and South Asian countries have a TGC score of 1, and most sub-Saharan African countries have a TGC score less than 1. This signifies that Asian countries lead world frontier technology and most African countries do not. The decomposition of efficiency scores showed that with regard to technical changes, African nations had progressed on average only 0.01%, and efficiency change scores had regressed by 0.59% annually.

  11. Green microfinance: the case of the Cresol System in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Lauro Gonzalez

    2015-08-01

    Full Text Available Climate change which until recently seemed a luxury for the microfinance sector, now appears to be crucial for the future of the sector. Due to their low adaptive capacity, the millions of MF clients worldwide happen to be the most vulnerable to a changing climate. Adapting previous analysis conducted in Nepal and Bangladesh by Agrawala and Maëlis (2010 to the Brazilian context, in this inductive qualitative study we aim to assess potential synergies between MF and CC actions and what strategies can be harnessed to better respond to CC vulnerabilities at client/MF level. To do so, we investigated the case of the second largest rural microcredit programme in Brazil, Sistema Cresol de Cooperativas de Crédito Rural com Interação Solidária. Albeit important overlaps between Cresol's product envelope and CC strategies exist, there is still room to realise synergies to both mitigate a new potential source of risk to Cresol's portfolio and to increase clients' adaptive capacity.

  12. Human Capital Accountability and Construct: Evidence from Islamic Microfinance Institutions in Malaysia

    Directory of Open Access Journals (Sweden)

    Amrizah Kamaluddin

    2018-03-01

    Full Text Available To identify the human capital construct that significantly relates to the performance of Islamic organizations, this study obtained data from Islamic microfinance organizations in Malaysia using the survey questionnaire method. In addition, we interviewed renowned scholars in the fields of Islamic accounting and Shariah law. Consequently, this study proposes an extended model of human capital that is applicable to Islamic organizations. Apart from knowledge and competency, this study includes spiritual value as another construct of human capital in Islamic organizations. Knowledge includes ideas that are relevant to the accounting and auditing spectra, as well as Shariah principles and jurisprudence. By contrast, competency refers to the ability to innovate unique Shariah-compliant products that are rare and difficult to imitate. Meanwhile, spiritual values embrace the elements of “Siddiq,” “Amanah,” “Fathonah,” and “Tabligh.” This study affirms that knowledge, competency, and satisfaction are the most significant constructs of human capital that explain performance. Factor analysis indicates that spiritual value is embedded in and forms part of the human capital construct. Hence, spiritual value is a key element in company culture and contributes significantly to organizational success. This model can be a platform for human capital reporting in the relevant Islamic and conventional organizations.

  13. The root caused analysis of leakaged heat exchanger tube

    International Nuclear Information System (INIS)

    Shamsudin, Shaiful Rizam; Salleh, M.A.A. Mohd; Rahmat, Azmi; Anuar, Mohd Arif; Harun, Mohd; Zayid, Hafizal; Noor, Mazlee Mohd

    2015-01-01

    AISI type 316L stainless steel was used as a heat exchanger tube material in an inter-cooler column. After less than a year of operation, severe corrosion failures occurred and a transverse opening leakage was observed on one of the heat exchanger tubes. The failed tube was carefully analyzed using various metallurgical laboratory equipments. The root cause of the tube leakage was believed due to the presence of horizontal micro and macro pores as a hydrogen gas entrapment during casting of the parent ingot. The overlapped and gaping pores formed notch on the shell side of the tube surface, and it increasingly evident when the use of a high-energy water-jet and metal brush as cleaning procedure results in an establishment of pitting type local-action corrosion cells penetrated the tube wall. As a result, corrosive fluid in the tube side dissolved into the cooling water, accelerating the corrosion process.

  14. Horizontal drilling under Lake Erie

    Energy Technology Data Exchange (ETDEWEB)

    Meller, R.

    2001-07-01

    Drilling oil wells under Lake Erie calls for horizontal drilling wells to be drilled from shore out into the pay-zone under the lake. The nature and characteristics of horizontal wells as compared to vertical wells are explored. Considerations that have to be taken into account in drilling horizontal wells are explained (the degree of curvature, drilling fluid quality, geosteering in the pay-zone, steering instrumentation, measurements while drilling (MWD), logging while drilling (LWD)). The concept and reasons for extended reach wells are outlined, along with characteristic features of multilateral wells.

  15. Where do the poorest go to seek outpatient care in Bangladesh: hospitals run by government or microfinance institutions?

    Science.gov (United States)

    Tseng, Yu-hwei; Khan, Mujibul Alam

    2015-01-01

    Health programs implemented by microfinance institutions (MFIs) aim to benefit the poor, but whether these services reach the poorest remains uncertain. This study intended to investigate the socioeconomic distribution of patients in hospitals operated by microfinance institutions (i.e. MFI hospitals) in Bangladesh and compare the differences with public hospitals to determine if the programs were consistent with their pro-poor mandate. In this cross-sectional study, we used the convenience sampling method to conduct an interviewer-assisted questionnaire survey among 347 female outpatients, with 170 in public hospitals and 177 in MFI hospitals. Independent variables were patient characteristics categorized into predisposing factors (age, education, marital status, family size), enabling factors (microcredit membership, household income) and need factors (self-rated health, perceived needs for care). We employed Generalized Estimating Equations (GEE) to evaluate how these factors contributed to MFI hospital use. Use of MFI hospitals was associated with microcredit membership over 5 years (OR=2.9, pmicrocredit members had a higher tendency towards utilization but membership effect pertained to the non- and moderately-poor. Compared with the group who were non-members and the poorest, microcredit members who were non-poor had the highest likelihood (OR=7.46, p<.001) to visit MFI hospitals, followed by members with moderate income (OR=6.91, p<.001) and then non-members in non-poor households (OR=4.48, p<.01). Those who were members but the poorest had a negative association (OR=0.42), though not significant. Despite a higher utilization of preventive services in MFI hospitals, expenditure there was significantly higher. Inequity was more pronounced in MFI hospitals than public ones. MFI hospitals appeared to miss their target population. We suggest that MFIs reorganize health programs toward primary health care to make care equitable and universally accessible. This

  16. Eustachian tube patency

    Science.gov (United States)

    Eustachian tube patency refers to how much the eustachian tube is open. The eustachian tube runs between the middle ear and the throat. It controls the pressure behind the eardrum and middle ear space. This helps keep ...

  17. Feeding tube - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007235.htm Feeding tube - infants To use the sharing features on this page, please enable JavaScript. A feeding tube is a small, soft, plastic tube placed ...

  18. Tube holding system

    International Nuclear Information System (INIS)

    Cunningham, R.C.

    1978-01-01

    A tube holding rig is described for the lateral support of tubes arranged in tight parcels in a heat exchanger. This tube holding rig includes not less than two tube supporting assemblies, with a space between them, located crosswise with respect to the tubes, each supporting assembly comprising a first set of parallel components in contact with the tubes, whilst a second set of components is also in contact with the tubes. These two sets of parts together define apertures through which the tubes pass [fr

  19. Assessment of the Conditions for Linking Microfinance to Household Biodigester Construction in Cambodia

    Energy Technology Data Exchange (ETDEWEB)

    Chandararot, K.; Dannet, L.

    2006-10-15

    This report presents a comprehensive assessment of the conditions for helping households finance the construction of a biodigester. A micro-credit programme for biodigester users was jointly designed by the National Biodigester Programme (NBP), Netherlands Development Finance Company (FMO) and Microfinance Institutions (MFIs). By using in-depth interviews, a household survey and a desk study, it was determined that the demand for biodigester market was significant, with 96.5% of the studied households possessing the capacity to operate a biodigester. The research for demand for micro-credit showed that households were indeed in need of a financial aid (84%) but the majority was unwilling to borrow credit due to fear of inability to repay it. The ones willing to borrow demanded a credit size of 400,000-1,200,000 riels. The MFIs contacted (ACLEDA, Amret, CEB, Prasac, HURREDO) were interested in lending a micro-credit to biodigester users but were also concerned for the credit as it was for consumption and not production. It appeared that credit conditions desired by potential biodigester users were overall in line with MFIs offered conditions, but an interest rate gap was also in place. Some of the extensive suggestions on how to alleviate the problem offered in the report place FMO in the centre of operations as a possible guarantor of default loans, among other duties. The challenges likely to arise because of a roll-out strategy (linking potential biodigester users with micro-credit), as well plausible solutions are presented as well.

  20. Determinants of microfinance outreach in Sub-Saharan Africa: A panel approach

    Directory of Open Access Journals (Sweden)

    Abdulai Adams

    2017-01-01

    Full Text Available Orientation: The study focused on analysing the outreach performance of microfinance institutions (MFIs in providing critical services for the poor using innovative lending techniques within constrained environments. Research purpose: The study examined the trade-off relations between the depth and the breadth of outreach and identified institutional level factors that influence MFIs outreach in sub-Saharan Africa (SSA. Motivation for the study: MFIs continue to play critical roles in extending financial services to the poor and yet previous studies have not analysed comprehensively the dimensions of outreach necessary for financial inclusion. Research design, approach and methods: The study employed correlation analysis and random effects methodology to panel data regression analysis (619 observations, 71 MFIs across 10 countries to establish the trade-off relations and the determinants of outreach in SSA. Main findings: It was established that a trade-off exists between the depth of outreach (access to credit disbursement by poor clients and breadth of outreach (number of clients served. The results further revealed that gross loan portfolio, portfolio at risk, borrower per staff member, interest rate, and operating expenses to assets ratio are the main institutional determinants of MFIs outreach in SSA. Practical/managerial implications: The policy implication is that MFIs that concentrate efforts in reaching the relatively poor do so at the expense of reaching a large number of poor clients. We suggest that effective monitoring of depth and breadth and the adoption and implementation of cost-saving outreach technologies by MFIs could enable them to operate sustainably and efficiently. Contribution/value added: A major contribution of the study is the trade-off relations revealed between the depth of outreach and the breadth of outreach of MFIs which advances the outreach literature.

  1. Empowerment as a multifaceted concept: : The impact of offering goal setting training to couples in the context of a microfinance intervention for women.

    NARCIS (Netherlands)

    Huis, Marloes; Hansen, Nina; Otten, Sabine; Lensink, Bernardus

    2016-01-01

    Previous research on the impact of offering access to microfinance (micro loan and training) to women provided mixed results with respect to female empowerment. We propose that empowerment is a three-level concept and should be investigated at the personal, relational, and societal level. In the

  2. Understanding female empowerment : The impact of offering goal setting training to couples in the context of a microfinance intervention for women

    NARCIS (Netherlands)

    Huis, Marloes; Hansen, Nina; Otten, Sabine; Lensink, Bernardus

    2016-01-01

    Previous research on the impact of offering access to microfinance (micro loan and training) to women provided mixed results with respect to female empowerment. We propose that empowerment is a three-level concept and should be investigated at the personal, relational, and societal level. In the

  3. Through Islamic Banks’ Zakat House (IBZH: Investment of Zakah Funds in Microfinance to Remove Poverty in Bangladesh: A New Model

    Directory of Open Access Journals (Sweden)

    Ahm Ershad UDDIN

    2016-04-01

    Full Text Available AbstractOne of Zakat’s main objectives is to help eliminate poverty and famine. And in Shari’ah, the obligation of zakat payment is elaborated which if not maintained holds severe consequences. Zakat has its unique features of supporting the poor in providing a collateral free financial stability. The main socioeconomic factors in all the developing Muslim countries are poverty, unemployment and economic inequality which results in not meeting the basic needs of the poor. In a country like Bangladesh consisting of Muslim Majority, although governmental and non-governmental institutions collect and distribute zakat yet the ultimate goal of zakat is not attained completely. At present, modern Islamic jurists reinforce the notion of microfinance investment through the collection and usage of zakat money. This paper consists of a static ground for the poverty removal creating a financial institution which is equally responsible as those present in Bangladesh but with a different route in eliminating poverty where schemes can be initiated along with opening opportunities of employment. Finally, it also surfaces the model in investment of zakat fund through IBZH with opinions of Islamic jurists. This Islamic Banks Zakah House (IBZH is an amalgamated forum of the present eight established private Islamic banks of Bangladesh  Keywords: Islamic Banks’ Zakat House (IBZH, Microfinance, Bangladesh.

  4. Bender/Coiler for Tubing

    Science.gov (United States)

    Stoltzfus, J. M.

    1983-01-01

    Easy-to-use tool makes coils of tubing. Tubing to be bend clamped with stop post. Die positioned snugly against tubing. Operator turns handle to slide die along tubing, pushing tubing into spiral groove on mandrel.

  5. Stackelberg equilibria and horizontal differentiation

    OpenAIRE

    Lambertini, Luca

    1993-01-01

    This paper proposes a taxonomy of the Stackelberg equilibria emerging from a standard game of horizontal differentiation à la Hotelling in which the strategy set of the sellers in the location stage is the real axis. Repeated leadership appears the most advantageous position. Furthermore, this endogenously yields vertical differentiation between products at equilibrium.

  6. Horizontal Diplopia Following Upper Blepharoplasty

    Directory of Open Access Journals (Sweden)

    Tomás Ortiz-Basso

    2014-09-01

    Full Text Available Diplopia is an infrequent complication after blepharoplasty. Most of the cases are in its vertical form due to trauma of the extraocular muscles. In this article, we present a case of horizontal diplopia following cosmetic upper blepharoplasty; we review the literature on this unexpected complication and offer some recommendations to avoid it.

  7. Mechanistic multidimensional analysis of horizontal two-phase flows

    International Nuclear Information System (INIS)

    Tselishcheva, Elena A.; Antal, Steven P.; Podowski, Michael Z.

    2010-01-01

    The purpose of this paper is to discuss the results of analysis of two-phase flow in horizontal tubes. Two flow situations have been considered: gas/liquid flow in a long straight pipe, and similar flow conditions in a pipe with 90 deg. elbow. The theoretical approach utilizes a multifield modeling concept. A complete three-dimensional two-phase flow model has been implemented in a state-of-the-art computational multiphase fluid dynamics (CMFD) computer code, NPHASE. The overall model has been tested parametrically. Also, the results of NPHASE simulations have been compared against experimental data for a pipe with 90 deg. elbow.

  8. Investigation of straitified and countercurrent flows in horizontal piping during a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Bourteele, J.P.

    1980-06-01

    The ECTHOR program consists in a loop having as objective to study the flow regimes in horizontal pipings (stratification, countercurrent flows) in conditions representative of small break transients within commercial PWR. The ECTHOR tests are in process. Experimental results are already available and are presented in this paper: scaling problem, U tube experiments, hot leg experiments, high pressure tests

  9. Wireline tractor production logging experience in Australian horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Local, E.; Searight, T. L.

    1998-12-31

    Australian experiences with the development of new wireline tractor technology and its successful application to deploy production logging tools in horizontal wells was discussed. Dynamics of the tractor operations have been modelled and the model was validated with field data. The field data was also used to quantify borehole friction coefficients. Successful application in the field indicates that the tough tubing capability of the tractor, combined with its capacity to drive in large casing sizes, makes wireline deployment possible in a wide range of well completions. Work on a number of new applications such as the capability to negotiate complex downhole hardware, and to intervene in completions with widely differing tubing diameters, is in progress. 5 refs., 1 tab., 10 figs.

  10. X-ray tubes

    International Nuclear Information System (INIS)

    Young, R.W.

    1979-01-01

    A form of x-ray tube is described which provides satisfactory focussing of the electron beam when the beam extends for several feet from gun to target. Such a tube can be used for computerised tomographic scanning. (UK)

  11. Pressure tube type reactors

    International Nuclear Information System (INIS)

    Komada, Masaoki.

    1981-01-01

    Purpose: To increase the safety of pressure tube type reactors by providing an additional ECCS system to an ordinary ECCS system and injecting heavy water in the reactor core tank into pressure tubes upon fractures of the tubes. Constitution: Upon fractures of pressure tubes, reduction of the pressure in the fractured tubes to the atmospheric pressure in confirmed and the electromagnetic valve is operated to completely isolate the pressure tubes from the fractured portion. Then, the heavy water in the reactor core tank flows into and spontaneously recycles through the pressure tubes to cool the fuels in the tube to prevent their meltdown. By additionally providing the separate ECCS system to the ordinary ECCS system, fuels can be cooled upon loss of coolant accidents to improve the safety of the reactors. (Moriyama, K.)

  12. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    Feeding - gastrostomy tube - bolus; G-tube - bolus; Gastrostomy button - bolus; Bard Button - bolus; MIC-KEY - bolus ... KEY, 3 to 8 weeks after surgery. These feedings will help your child grow strong and healthy. ...

  13. Feeding tube insertion - gastrostomy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002937.htm Feeding tube insertion - gastrostomy To use the sharing features on this page, please enable JavaScript. A gastrostomy feeding tube insertion is the placement of a feeding ...

  14. Neural Tube Defects

    Science.gov (United States)

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

  15. Leveraging microfinance to impact HIV and financial behaviors among adolescents and their mothers in West Bengal: a cluster randomized trial.

    Science.gov (United States)

    Spielberg, Freya; Crookston, Benjamin T; Chanani, Sheila; Kim, Jaewhan; Kline, Sean; Gray, Bobbi L

    2013-01-01

    Microfinance can be used to reach women and adolescent girls with HIV prevention education. We report findings from a cluster-randomized control trial among 55 villages in West Bengal to determine the impact of non-formal education on knowledge, attitudes and behaviors for HIV prevention and savings. Multilevel regression models were used to evaluate differences between groups for key outcomes while adjusting for cluster correlation and differences in baseline characteristics. Women and girls who received HIV education showed significant gains in HIV knowledge, awareness that condoms can prevent HIV, self-efficacy for HIV prevention, and confirmed use of clean needles, as compared to the control group. Condom use was rare and did not improve for women. While HIV testing was uncommon, knowledge of HIV-testing resources significantly increased among girls, and trended in the positive direction among women in intervention groups. Conversely, the savings education showed no impact on financial knowledge or behavior change.

  16. Funding for self-employment of people with disabilities. Grants, loans, revolving funds or linkage with microfinance programmes.

    Science.gov (United States)

    de Klerk, Ton

    2008-03-01

    In 2005, Handicap International commissioned a study on the practices of funding for self-employment activities of people with disabilities (PWD), with a special focus on access to microfinance. The overall goal of the study was to produce a framework document highlighting good practices, strategies, tools and operational methods that guarantee the efficiency and sustainability of self-employment projects for PWDs. The first phase of the study consisted of a literature review and a worldwide survey. Through this first phase the research team identified the most innovative programmes for further analysis through field visits. In the second phase field visits were conducted in Afghanistan, Bangladesh, Ethiopia, India, Kenya, Nicaragua and Uganda, while regional workshops were organised in Dhaka and Nairobi. Phase three involved consolidation and analysis of the information and finally drafting of the framework document. This paper summarises the findings and good practices as presented in the framework document, based on the results of the literature review, the survey and the field research. It is not a scientific paper, i.e. it doesn't contain a discussion of the literature reviewed or systematic reference to sources, the same as the document on which it is based, as it is primarily meant for 'practitioners'. A main finding of the study was that there is no single 'best solution' to funding of self employment activities. While inclusion of PWDs in existing microfinance institutions (MFIs) is the preferred strategy, guaranteeing efficiency, sustainability and future access to funding for the target group, it was found that in reality many PWDs do not have access to microfinance programmes. This can be explained by stigmatisation of PWDs by staff of MFIs, who do not believe in their income earning and repayment capacity, and self-exclusion by PWDs. To fight against it projects have been set-up linking MFIs with programmes for PWDs, focusing on better information

  17. The Winfrith horizontal impact rig

    International Nuclear Information System (INIS)

    Barr, P.

    1985-12-01

    The Horizontal Impact Rig has been designed to allow studies of the impact of radioactive material transport containers and their associated transport vehicles and impact limiters, using large scale models, and to allow physically large missiles to be projected for studying the impact behaviour of metal and concrete structures. It provides an adequately rigid support structure for impact experiments with targets of large dimensions. Details of its design, instrumentation, performance prediction and construction are given. (U.K.)

  18. Atmospheric horizontal divergence and diffusion

    International Nuclear Information System (INIS)

    Castans, M.

    1981-01-01

    The action of horizontal divergence on diffusion near the ground is established through.a very simple flow model. The shape of the well-known Pasquill-Gifford-Turner curves, that apparently take account in some way of divergence, is justified. The possibility of explaining the discre--pancies between the conventional straight line model and experimental results, mainly under low-wind-speed satable conditions, is considered. Some hints for further research are made. (auth.)

  19. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    Science.gov (United States)

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

  20. Evaluation of the Effect of Tube Pitch and Surface Alterations on Temperature Field at Sprinkled Tube Bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2015-01-01

    Full Text Available Water flowing on a sprinkled tube bundle forms three basic modes: It is the Droplet mode (liquid drips from one tube to another, the Jet mode (with an increasing flow rate droplets merge into a column and the Membrane (Sheet mode (with further increasing of falling film liquid flow rate columns merge and create sheets between the tubes. With sufficient flow rate sheets merge at this state and the tube bundle is completely covered by a thin liquid film. There are several factors influencing the individual mode types as well as heat transfer. Beside the above mentioned falling film liquid flow rate they are for instance tube diameters, tube pitches in a tube bundle or a physical condition of a falling film liquid. This paper presents a summary of data measured at atmospheric pressure at a tube bundle consisting of copper tubes of 12 milimeters diameter and of the studied tube length one meter. The tubes are positioned horizontally one above another with the tested pitches of 15, 20, 25 and 30 mm and there is a distribution tube placed above them with water flowing out. The thermal gradient of 15–40 has been tested with all pitches where the falling film liquid’s temperature at the inlet of the distribution tube was 15 °C. The liquid was heated during the flow through the exchanger and the temperature of the sprinkled (heater liquid at the inlet of the exchanger with a constant flow rate about 7.2 litres per minute was 40 °C. The tested flow of the falling film liquid ranged from 1.0 to 13.0 litres per minute. Sequences of 180 exposures have been recorded in partial flow rate stages by thermographic camera with record frequency of 30 Hz which were consequently assessed using the Matlab programme. This paper presents results achieved at the above mentioned pitches and at three types of tube bundle surfaces.

  1. 21 CFR 868.5800 - Tracheostomy tube and tube cuff.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheostomy tube and tube cuff. 868.5800 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5800 Tracheostomy tube and tube cuff. (a) Identification. A tracheostomy tube and tube cuff is a device intended to be placed into a...

  2. comparative evaluation of pressure distribution between horizontal

    African Journals Online (AJOL)

    user

    This paper presents comparative analysis between the pressure behavior of ... Green and source function were used to evaluate the performance of horizontal well and ..... Superscript. ' derivative. D = dimensionless. h = horizontal. = change.

  3. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Gugel, G.

    1976-01-01

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  4. Experimental study on two-phase flow in horizontal duct using a visualization technique; Estudo experimental de escoamentos bifasicos em duto horizontal usando uma tecnica de visualizacao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Livia A.; Tomas, Bruno T.; Cunha Filho, Jurandyr S.; Su, Jian, E-mail: livia.alves.oliveira@gmail.co [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose L.H. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    In this paper an experimental study is performed for visualization of water-air two phase flow, stratified and intermittent, in a 51 mm internal diameter circular section horizontal tube. The study consists in filming a water-air mixture passin by a transparent interval of the tube, using a high speed camera. After that, the obtained images are analysed frame after frame and then, data are extracted of weight of gas-liquid interfaces, length and gas bubbles speeds. Then, these data are verified with experimental and theoretical correlations available in the literature

  5. Charging and discharging characteristics of cool thermal energy storage system with horizontal pipes using water as phase change material

    International Nuclear Information System (INIS)

    Sait, H.H.; Selim, A.M.

    2014-01-01

    Highlights: • Ice is formed around horizontal tubes. • Optimum solid ice releasing is found. • Freezing and releasing of ice are controlled by ice resistance, time and tubes spacing. - Abstract: An experimental investigation of ice formation on cold vertical banks of horizontal tubes subjected to falling-film– jet mode– is conducted. In the charging process, a set of internally cooled vertical banks of horizontal tubes of brine is subjected to a falling film of water. The formed ice is periodically observed, photographed and measured in falling-film jet mode at specific internal coolant (ethylene–glycol solution) flow rates and temperatures. In the discharge process, the same solution is heated and used internally to release ice. Different thicknesses of the released ice are observed and measured. The maximum quantity of released ice is obtained and the optimum ice formation is determined. The results indicate that the ice formation and the solid ice released are controlled by the thermal resistance of the ice, time and pitch between tubes. The maximum gained ice has a thickness that is approximately equal to half of the tube spacing between the tubes utilized, which is formed in approximately 45 min and released in 12.5 min. The variation in heating solution temperature has a slight effect on the gained ice and discharging time

  6. Bubble shape in horizontal and near horizontal intermittent flow

    International Nuclear Information System (INIS)

    Gu, Hanyang; Guo, Liejin

    2015-01-01

    Highlights: • The bubble shapes in intermittent flows are presented experimentally. • The nose-tail inversion phenomenon appears at a low Froude number in downward pipe. • Transition from plug to slug flow occurs when the bubble tail changes from staircase pattern to hydraulic jump. - Abstract: This paper presents an experimental study of the shape of isolated bubbles in horizontal and near horizontal intermittent flows. It is found that the shapes of the nose and body of bubble depend on the Froude number defined by gas/liquid mixture velocity in a pipe, whereas the shape of the back of bubble region depends on both the Froude number and bubble length. The photographic studies show that the transition from plug to slug flow occurs when the back of the bubble changes from staircase pattern to hydraulic jump with the increase of the Froude number and bubble length. The effect of pipe inclination on characteristics of bubble is significant: The bubble is inversely located in a downwardly inclined pipe when the Froude number is low, and the transition from plug flow to slug flow in an upward inclined pipe is more ready to occur compared with that in a downwardly inclined pipe

  7. Intercostal drainage tube or intracardiac drainage tube?

    Directory of Open Access Journals (Sweden)

    N Anitha

    2016-01-01

    Full Text Available Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  8. Intercostal drainage tube or intracardiac drainage tube?

    Science.gov (United States)

    Anitha, N; Kamath, S Ganesh; Khymdeit, Edison; Prabhu, Manjunath

    2016-01-01

    Although insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure.

  9. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia Embedded video for NEI YouTube Videos: ...

  10. Split core experiments; Part I. Axial neutron flux distribution measurements in the reactor core with a central horizontal reflector

    Energy Technology Data Exchange (ETDEWEB)

    Strugar, P; Raisic, N; Obradovic, D; Jovanovic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1965-05-01

    A series of critical experiments were performed on the RB reactor in order to determine the thermal neutron flux increase in the central horizontal reflector formed by a split reactor core. The objectives of these experiments were to study the possibilities of improving the thermal neutron flux characteristics of the neutron beam in the horizontal beam tube of the RA research reactor. The construction of RA reactor enables to split the core in two, to form a central horizontal reflector in front of the beam tube. This is achieved by replacing 2% enriched uranium slugs in the fuel channel by dummy aluminium slugs. The purpose of the first series of experiments was to study the gain in thermal neutron component inside the horizontal reflector and the loss of reactivity as a function of the lattice pitch and central reflector thickness.

  11. Leveraging strong social ties among young men in Dar es Salaam: A pilot intervention of microfinance and peer leadership for HIV and gender-based violence prevention.

    Science.gov (United States)

    Maman, Suzanne; Kajula, Lusajo; Balvanz, Peter; Kilonzo, Mrema; Mulawa, Marta; Yamanis, Thespina

    2016-12-01

    Gender inequality is at the core of the HIV patterns that are evident in sub-Saharan Africa. Gender-based violence (GBV) and lack of economic opportunity are important structural determinants of HIV risk. We piloted a microfinance and health promotion intervention among social networks of primarily young men in Dar es Salaam. Twenty-two individuals participated in the microfinance component and 30 peer leaders were recruited and trained in the peer health leadership component. We collected and analysed observational data from trainings, monitoring data on loan repayment, and reports of peer conversations to assess the feasibility and acceptability of the intervention. Eighteen of the loan recipients (82%) paid back their loans, and of these 15 (83%) received a second, larger loan. Among the loan defaulters, one died, one had chronic health problems, and two disappeared, one of whom was imprisoned for theft. The majority of conversations reported by peer health leaders focused on condoms, sexual partner selection, and HIV testing. Few peer leaders reported conversations about GBV. We demonstrated the feasibility and acceptability of this innovative HIV and GBV prevention intervention. The lessons learned from this pilot have informed the implementation of a cluster-randomised trial of the microfinance and peer health leadership intervention.

  12. Is product diversification the Ultimate Quid Pro Quo for Gender sensitive Poverty Alleviation? Adverse Social Externalities from Combined Microfinance in Latin America and the Caribbean

    Directory of Open Access Journals (Sweden)

    ROSSEL-CAMBIER, Koen

    2013-11-01

    Full Text Available Documented deficiencies in traditional social transfer mechanisms have led to the emergence of alternative methods for reducing poverty. In many countries, microfinance institutions (MFIs have become popular instruments for redistributive propoor policies. However, they are also criticised for not being inclusive enough. This paper explores if product diversification has an effect on poverty outreach, in particular when combining micro- credit with savings and insurance. It applies cross-sectional analysis of 250 microfinance schemes in Latin America and the Caribbean. By focusing on elements of the depth of poverty outreach, the research highlights a number of possible effects of combined microfinance (CMF. Product diversification can significantly contribute to increased social outreach («breadth» of poverty outreach. However, the findings suggest that, in the case of combining credit with savings, this is leading to a relatively lower participation of poor and female clients («depth» of poverty outreach. Exclusionary and discriminatory vulnerabilities and dynamics, linked to specific financial products, may apply double or even reinforce each other. Cumulative financial, cultural, geographical or communication barriers can make participation in multiple financial products more challenging. These findings have not been adequately tackled by academic literature, but are most relevant for MFI stakeholders and policy makers. If gender-sensitive or pro-poor income generation is at the heart of the mission of MFIs, corrective measures to these forms of adverse externalities should be considered.

  13. Piloting a Savings-Led Microfinance Intervention with Women Engaging in Sex Work in Mongolia: Further Innovation for HIV Risk Reduction.

    Science.gov (United States)

    Tsai, Laura Cordisco; Witte, Susan S; Aira, Toivgoo; Altantsetseg, Batsukh; Riedel, Marion

    2011-12-30

    This paper describes a pilot study testing the feasibility of an innovative savings-led microfinance intervention in increasing the economic empowerment and reducing the sexual risk behavior of women engaging in sex work in Mongolia. Women's economic vulnerability may increase their risk for HIV by compromising their ability to negotiate safer sex with partners and heightening the likelihood they will exchange sex for survival. Microfinance has been considered a potentially powerful structural HIV prevention strategy with women conducting sex work, as diversification of income sources may increase women's capacity to negotiate safer transactional sex. With 50% of all reported female HIV cases in Mongolia detected among women engaging in sex work, direct prevention intervention with women conducting sex work represents an opportunity to prevent a potentially rapid increase in HIV infection in urban Mongolia. The piloted intervention consisted of a matched savings program in which matched savings could be used for business development or vocational education, combined with financial literacy and business development training for women engaging in sex work. Results of the pilot demonstrate participants' increased confidence in their ability to manage finances, greater hope for pursuing vocational goals, moderate knowledge gains regarding financial literacy, and an initial transition from sex work to alternative income generation for five out of nine participants. The pilot findings highlight the potential for such an intervention and the need for a clinical trial testing the efficacy of savings-led microfinance programs in reducing HIV risk for women engaging in sex work in Mongolia.

  14. Environmental restoration using horizontal wells

    International Nuclear Information System (INIS)

    Looney, B.B.; Kaback, D.S.; Hazen, T.C.; Corey, J.C.

    1992-01-01

    This paper reports that under sponsorship from the U.S. Department of Energy, technical personnel from the Savannah River Laboratory and other DOE laboratories, universities and private industry have completed a full scale demonstration of environmental remediation using horizontal wells. The test successfully removed approximately 7250 kg of contaminants. A large amount of characterization and monitoring data was collected to aid in interpretation of the test and to provide the information needed for future environmental restorations that employ directionally drilled wells as extraction or delivery systems

  15. Pediatric cuffed endotracheal tubes

    Directory of Open Access Journals (Sweden)

    Neerja Bhardwaj

    2013-01-01

    Full Text Available Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H 2 O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

  16. Horizontal gene transfer in chromalveolates

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debashish

    2007-09-01

    Full Text Available Abstract Background Horizontal gene transfer (HGT, the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists. Results We identified 16 proteins that have originated in chromalveolates through ancient HGTs before the divergence of the genera Karenia and Karlodinium and one protein that was derived through a more recent HGT. Detailed analysis of the phylogeny and distribution of identified proteins demonstrates that eight have resulted from independent HGTs in several eukaryotic lineages. Conclusion Recurring intra- and interdomain gene exchange provides an important source of genetic novelty not only in parasitic taxa as previously demonstrated but as we show here, also in free-living protists. Investigating the tempo and mode of evolution of horizontally transferred genes in protists will therefore advance our understanding of mechanisms of adaptation in eukaryotes.

  17. Equipment for inspection and carrying out repairs, if required, for tube bundles of steam raising units

    International Nuclear Information System (INIS)

    Gugel, G.

    1976-01-01

    The equipment solves the problem of being able to inspect and possibly to repair U-tubes of a vertical steam raising unit standing on a tube floor, without draining the primary medium and bringing the test equipment and tools into the inside of the boiler first. This is achieved by leaving a considerable part of the equipment permanently in the hemispherical space under the tube floor and operating it from the outside, on the other side of the concrete shielding. An inspection tube is threaded in turn horizontally through a concrete shield, a tube duct in the heat insulation of the steam raising unit, and through a hole in the hemispherical space under the tube floor into this space. The end of an angle tube can be moved axially from outside the concrete shield and can be rotated in a semicircle above the tube axis. By interposing a, for example, 12 part distributor with 12 short, differently bent tubes 12 adjacent tubes opening into the tube floor can be controlled and tested, by axial movement of the angle tube together with the distributor, e.g. 4 x 12 other U tubes. A turbulent flow sensor, for example, can be introduced through the angle tube and distributor. In the non-operational condition the equipment is moved into a recess via a supporting angle and stopped there. (ORU) [de

  18. Improved waterflooding efficiency by horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Popa, C. G. [Petroleum and Gas Univ., Ploesti (Romania); Clipea, M. [SNP Petrom SA, ICPT Campina (Romania)

    1998-12-31

    The influence of well pattern involving the use of horizontal wells on the overall efficiency of the waterflooding process was analyzed. Three different scenarios were examined: (1) a pattern of using two parallel horizontal wells, one for injection, the other for production, (2) a pattern of one horizontal well for water injection and several vertical wells for production, and (3) a pattern of using vertical wells for injection and one horizontal well for production. In each case, the waterflooding process was simulated using a two phase two dimensional numerical model. Results showed that the pressure loss along the horizontal section had a large influence on the sweep efficiency whether the horizontal well was used for injection or production. Overall, the most successful combination appeared to be using vertical wells for injection and horizontal wells for production. 4 refs., 1 tab., 15 figs.

  19. Lunar Lava Tube Sensing

    Science.gov (United States)

    York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

    1992-01-01

    Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

  20. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube......’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within...

  1. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1983-08-01

    A review of the performance of steam generator tubes in 110 water-cooled nuclear power reactors showed that tubes were plugged at 46 (42 percent) of the reactors. The number of tubes removed from service increased from 1900 (0.14 percent) in 1980 to 4692 (0.30 percent) in 1981. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that used all-volatile treatment since start-up. At one reactor a large number of degraded tubes were repaired by sleeving which is expected to become an important method of tube repair in the future

  2. Rectangular drift tube characteristics

    International Nuclear Information System (INIS)

    Denisov, D.S.; Musienko, Yu.V.

    1985-01-01

    Results on the study of the characteristics of a 50 x 100 mm aluminium drift tube are presented. The tube was filled with argon-methane and argon-isobutane mixtures. With 16 per cent methane concentration the largest deviation from a linear relation between the drift time and the drift path over 50 mm is less than 2 mm. The tube filled with argon-isobutane mixture is capable of operating in a limited streamer mode

  3. Two-phase flow field simulation of horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Rabiee, Ataollah; Kamalinia, Amir Hossein; Hadad, Kamal [School of Mechanical Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of)

    2017-02-15

    The analysis of steam generators as an interface between primary and secondary circuits in light water nuclear power plants is crucial in terms of safety and design issues. VVER-1000 nuclear power plants use horizontal steam generators which demand a detailed thermal hydraulics investigation in order to predict their behavior during normal and transient operational conditions. Two phase flow field simulation on adjacent tube bundles is important in obtaining logical numerical results. However, the complexity of the tube bundles, due to geometry and arrangement, makes it complicated. Employment of porous media is suggested to simplify numerical modeling. This study presents the use of porous media to simulate the tube bundles within a general-purpose computational fluid dynamics code. Solved governing equations are generalized phase continuity, momentum, and energy equations. Boundary conditions, as one of the main challenges in this numerical analysis, are optimized. The model has been verified and tuned by simple two-dimensional geometry. It is shown that the obtained vapor volume fraction near the cold and hot collectors predict the experimental results more accurately than in previous studies.

  4. Categorising YouTube

    OpenAIRE

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a...

  5. Pressure tube reactor

    International Nuclear Information System (INIS)

    Susuki, Akira; Murata, Shigeto; Minato, Akihiko.

    1993-01-01

    In a pressure tube reactor, a reactor core is constituted by arranging more than two units of a minimum unit combination of a moderator sealing pipe containing a calandria tube having moderators there between and a calandria tube and moderators. The upper header and a lower header of the calandria tank containing moderators are communicated by way of the moderator sealing tube. Further, a gravitationally dropping mechanism is disposed for injecting neutron absorbing liquid to a calandria gas injection portion. A ratio between a moderator volume and a fuel volume is defined as a function of the inner diameter of the moderator sealing tube, the outer diameter of the calandria tube and the diameter of fuel pellets, and has no influence to intervals of a pressure tube lattice. The interval of the pressure tube lattice is enlarged without increasing the size of the pressure tube, to improve production efficiency of the reactor and set a coolant void coefficient more negative, thereby enabling to improve self controllability and safety. Further, the reactor scram can be conducted by injecting neutron absorbing liquid. (N.H.)

  6. Heated Tube Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Heated Tube Facility at NASA GRC investigates cooling issues by simulating conditions characteristic of rocket engine thrust chambers and high speed airbreathing...

  7. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1984-10-01

    A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization

  8. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Tapping, R.L.; Stipan, L.

    1992-03-01

    A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

  9. Steam generator tube rupture (SGTR) scenarios

    International Nuclear Information System (INIS)

    Auvinen, A.; Jokiniemi, J.K.; Laehde, A.; Routamo, T.; Lundstroem, P.; Tuomisto, H.; Dienstbier, J.; Guentay, S.; Suckow, D.; Dehbi, A.; Slootman, M.; Herranz, L.; Peyres, V.; Polo, J.

    2005-01-01

    The steam generator tube rupture (SGTR) scenarios project was carried out in the EU 5th framework programme in the field of nuclear safety during years 2000-2002. The first objective of the project was to generate a comprehensive database on fission product retention in a steam generator. The second objective was to verify and develop predictive models to support accident management interventions in steam generator tube rupture sequences, which either directly lead to severe accident conditions or are induced by other sequences leading to severe accidents. The models developed for fission product retention were to be included in severe accident codes. In addition, it was shown that existing models for turbulent deposition, which is the dominating deposition mechanism in dry conditions and at high flow rates, contain large uncertainties. The results of the project are applicable to various pressurised water reactors, including vertical steam generators (western PWR) and horizontal steam generators (VVER)

  10. Explorando nuevos horizontes en NASA

    Science.gov (United States)

    Villanueva, G. L.

    A pesar de la incesante expansión del Universo iniciada con el Big Bang 14 mil millones de años atrás, nuestro Universo se siente cada día más cercano. La inquebrantable vocación de la humanidad por descubrir nuevos horizontes ha permitido el acercamiento de civilizaciones en nuestro planeta y nos ha permitido conocer nuestro lugar en el Universo como nunca antes. En este artículo presento una breve sinopsis de nuestro trabajo que se relaciona con diversas investigaciones con implicaciones astrobiológicas, desde el origen de los ingredientes de la "sopa de la vida", hasta la evolución y composición de la atmósfera de Marte.

  11. Nuclear component horizontal seismic restraint

    International Nuclear Information System (INIS)

    Snyder, G.J.

    1988-01-01

    In a nuclear reactor having a reactor vessel, a reactor guard vessel, a thermal insulation shell and a horizontal seismic restraint, a restraint is described comprising: a. a first ring on the wall of the reactor vessel; b. a second ring on the wall of the reactor guard vessel in alignment with the first ring; c. a first block attached to the second ring proximate the first ring so as to provide a predetermined clearance between the first block and the first ring which is reduced to zero during thermal expansion; d. motion limit means extending through an aperture in the thermal insulation shell in alignment with the second ring and the first block; the e. a second block attached to the motion limit means proximate the second ring and in alignment the first block so as to provide a predetermined clearance between the second block and the second ring which is reduced to zero during thermal expansion

  12. WWER Steam Generators Tubing Performance and Aging Management

    International Nuclear Information System (INIS)

    Trunov, Nikolay B.; Davidenko, Stanislav E.; Grigoriev, Vladimir A.; Popadchuk, Valery S.; Brykov, Sergery I.; Karzov, Georgy P.

    2006-01-01

    At WWER NPPs the horizontal steam generators (SGs), are used that differ in design concept from vertical SGs mostly used at western NPPs. Reliable operation of SG heat-exchanging tubes is the crucial worldwide problem for NPP of various types. According to the operation feedback the water chemistry is the governing factor affecting operability of SG tubing. The secondary side corrosion is considered to be the main mechanism of SG heat-exchanging tubes damage at WWER plants. To make the assessment of the tubing integrity the combination of pressure tests and eddy-current tests is used. Assessment of the tubing performance is an important part of SG life extension practice. The given paper deals with the description of the tube testing strategy and the approach to tube integrity assessment based on deterministic and probabilistic methods of fracture mechanics. Requirements for eddy-current test are given as well. Practice of condition monitoring and implementing the database on steam generators operation are presented. The approach to tubes plugging criteria is described. The research activities on corrosion mechanism studies and residual lifetime evaluation are mentioned. (authors)

  13. Steam generator tube failures

    International Nuclear Information System (INIS)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  14. Development of Empirical Correlation to Calculate Pool Boiling Heat Transfer of Tandem Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Myeong-Gie [Andong National University, Andong (Korea, Republic of)

    2015-10-15

    The heat exchanging tubes are in vertical alignment. For the cases, the upper tube is affected by the lower tube. Since heat transfer is closely related to the conditions of tube surface, bundle geometry, and liquid, lots of studies have been carried out for the several decades to investigate the combined effects of those factors on pool boiling heat transfer. One of the most important parameters in the analysis of a tube array is the pitch ( P ) between tubes. Many researchers have been investigated its effect on heat transfer enhancement for the tube bundles and the tandem tubes. The effect of a tube array on heat transfer enhancement was also studied for application to the flooded evaporators. Cornwell and Schuller studied the sliding bubbles by high speed photography to account the enhancement of heat transfer observed at the upper tubes of a bundle. The study by Memory et al. shows the effects of the enhanced surface and oil adds to the heat transfer of tube bundles. They identified that, for the structured and porous bundles, oil addition leads to a steady decrease in performance. The flow boiling of n-pentane across a horizontal tube bundle was investigated experimentally by Roser et al. They identified that convective evaporation played a significant part of the total heat transfer. The fouling of the tube bundle under pool boiling was also studied by Malayeri et al. They identified that the mechanisms of fouling on the middle and top heater substantially differ from those at the bottom heater.

  15. Method for shaping polyethylene tubing

    Science.gov (United States)

    Kramer, R. C.

    1981-01-01

    Method forms polyethylene plastic tubing into configurations previously only possible with metal tubing. By using polyethylene in place of copper or stain less steel tubing inlow pressure systems, fabrication costs are significantly reduced. Polyethylene tubing can be used whenever low pressure tubing is needed in oil operations, aircraft and space applications, powerplants, and testing laboratories.

  16. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

    Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

  17. Experimental study on two-phase flow in horizontal duct using a visualization technique

    International Nuclear Information System (INIS)

    Oliveira, Livia A.; Tomas, Bruno T.; Cunha Filho, Jurandyr S.; Su, Jian

    2009-01-01

    In this paper an experimental study is performed for visualization of water-air two phase flow, stratified and intermittent, in a 51 mm internal diameter circular section horizontal tube. The study consists in filming a water-air mixture passin by a transparent interval of the tube, using a high speed camera. After that, the obtained images are analysed frame after frame and then, data are extracted of weight of gas-liquid interfaces, length and gas bubbles speeds. Then, these data are verified with experimental and theoretical correlations available in the literature

  18. Penetrating particles in horizontal air showers

    International Nuclear Information System (INIS)

    Wohlenberg, J.; Boehm, E.

    1975-01-01

    Particle density and arrival time of muons has been measured in Horizontal Air Showers. 5,600 showers have been recorded in 7,800 hours. Using stringent selection criteria 155 showers have been found horizontal (zenith angle larger 70 0 ) in the size range 4.1 > lg N > 5.5. The muons observed in these showers can be explained by purely electromagnetic origin of horizontal showers. (orig.) [de

  19. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  20. First Research Coordination Meeting on Prediction of Axial and Radial Creep in HWR Pressure Tubes. Presentations

    International Nuclear Information System (INIS)

    2013-01-01

    Pressure tube deformation is a critical aging issue in operating Heavy Water Reactors (HWRs). According to the service year, horizontal pressure tubes have three kinds of deformation: diametral creep leading to the flow bypass and the penalty to critical heat flux for fuel rods, longitudinal creep leading to the interference of feeder pipes and/or with fuelling machine, and sagging leading to the interference with in-core components and potential contact between the pressure tube and calandria tube. The CRP scope includes the establishment of a database for pressure tube deformation, microstructure characterization of pressure tube materials collected from HWRs currently operating in Member States and development of a prediction model for pressure tube deformation

  1. The root caused analysis of leakaged heat exchanger tube; Ursachenanalyse einer Leckage an einem Waermeuebertraegerrohr

    Energy Technology Data Exchange (ETDEWEB)

    Shamsudin, Shaiful Rizam; Salleh, M.A.A. Mohd; Rahmat, Azmi; Anuar, Mohd Arif [Universiti Malaysia Perlis (UniMAP) (Malaysia). Center of Excellence Geopolymer and Green Technology (CEGeoGTech); Harun, Mohd; Zayid, Hafizal [Malaysian Nuclear Agency, Selangor (Malaysia). Industry Technology Div.; Noor, Mazlee Mohd [Universiti Malaysia Perlis (UniMAP) (Malaysia). School of Materials Engineering

    2015-05-01

    AISI type 316L stainless steel was used as a heat exchanger tube material in an inter-cooler column. After less than a year of operation, severe corrosion failures occurred and a transverse opening leakage was observed on one of the heat exchanger tubes. The failed tube was carefully analyzed using various metallurgical laboratory equipments. The root cause of the tube leakage was believed due to the presence of horizontal micro and macro pores as a hydrogen gas entrapment during casting of the parent ingot. The overlapped and gaping pores formed notch on the shell side of the tube surface, and it increasingly evident when the use of a high-energy water-jet and metal brush as cleaning procedure results in an establishment of pitting type local-action corrosion cells penetrated the tube wall. As a result, corrosive fluid in the tube side dissolved into the cooling water, accelerating the corrosion process.

  2. Chemical placement in heterogeneous and long reach horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Stalker, Robert; Wahid, Fazrie; Graham, Gordon M.

    2006-03-15

    The effective placement of chemical squeeze treatments in heterogeneous wells and long reach horizontal wells has proved a significant challenge, with various factors including heterogeneity, crossflow and pressure gradients between otherwise non-communicating zones within the well, all contributing to an uneven placement of the scale squeeze treatment into the reservoir. Current methods to circumvent these problems often rely on extremely expensive coiled tubing operations, staged diversion (temporary shut off) treatments or by designing treatments to deliberately overdose some zones in order to gain placement in other (e.g. low permeability) zones. Moreover for deepwater sub sea horizontal wells the costs associated with ''spot'' treating along the length of horizontal wells by coil tubing tractor operations can often be prohibitively expensive. For other very near well bore treatments such as acid stimulation a number of self diverting strategies including gelled acid treatments, staged viscoelastic surfactant treatments and foams have been applied in field treatments with some success. However the properties which make such treatments applicable for acid stimulation may also make them inappropriate for bullhead scale squeeze treatments. Recent work by the current authors has however indicated the possible benefits of using modified injection fluids to aid uniform scale inhibitor placement in such wells in order to effect more even placement. In summary this paper will describe the various options available for achieving self diversion and describes the potential drawbacks associated with the viscous placement fluids commonly used for acid simulation techniques. In addition, various simulation packages commonly used for scale related calculations are reviewed and their limitations, primarily due to the inherent assumptions made and input parameters used, for modelling squeeze treatments using such modified fluids are described. The paper

  3. Heat transfer and pressure drop during flow boiling of R407C; Waermeuebergang und Druckverlust beim Stroemungssieden von R407C

    Energy Technology Data Exchange (ETDEWEB)

    Rollmann, Philipp; Spindler, Klaus [Stuttgart Univ. (DE). Inst. fuer Thermodynamik und Waermetechnik (ITW)

    2011-10-15

    The heat transfer and pressure drop during flow boiling of R407C in a horizontal microfin tube have been investigated. The measured heat transfer coefficient is compared with the correlations of Liu and Winterton as well as Cavallini et al. The measured pressure drop is compared with the correlations of Kuo and Wang as well as Mueller-Steinhagen and Heck. (orig.)

  4. Backyard Living – Integrative Policies Towards Migrant Workers: Housing Microfinance in Greater Ho Chi Minh City, Vietnam

    Directory of Open Access Journals (Sweden)

    Martin Noltze

    2008-01-01

    Full Text Available The urban agglomeration of the Vietnamese southeast industrial driving force Ho Chi Minh City (HCMC has become the most outstanding benefi ciary of the remarkable economic growth and foreign investments in the Vietnamese economy since the start of a comprehensive economic reform process in the mid 1980s. The notable development towards the foremost economic centre led to a high influx of migrant workers. In the course of an ongoing expansion process towards a megacity of tomorrow, the defi cient provision of adequate housing remains one of the most challenging problems of rural migrants in Greater HCMC. However, a future-oriented sustainable megacity concept is strongly dependent on the successful integration of migrants into the urban society. Within this context, the housing market is considered to be a key aspect of comprehensive urban planning. Hereby, housing microfinance (HMF will be presented as an alternative housing finance scheme meeting the demand of a noteworthy number of poor and low-income people. Thereby HMF can do both: focus on specifi c needs of migrants with respect to their current life situation and enhance its outreach to a potential target group.

  5. Compact Process for the Preparation of Microfine Spherical High-Niobium-Containing TiAl Alloy Powders

    Science.gov (United States)

    Tong, J. B.; Lu, X.; Liu, C. C.; Wang, L. N.; Qu, X. H.

    2015-03-01

    High-Nb-containing TiAl alloys are a new generation of materials for high-temperature structural applications because of their superior high-temperature mechanical properties. The alloy powders can be widely used for additive manufacturing, thermal spraying, and powder metallurgy. Because of the difficulty of making microfine spherical alloy powders in quantity by conventional techniques, a compact method was proposed, which consisted of two-step ball milling of elemental powders and subsequent radio frequency (RF) argon plasma spheroidization. In comparison with conventional mechanical alloying techniques, the two-step milling process can be used to prepare alloy powders with uniform scale in a short milling time with no addition of process control agent. This makes the process effective and less contaminating. After RF argon plasma spheroidization, the powders produced exhibit good sphericity, and the number-average diameter is about 8.2 μm with a symmetric unimodal particle size distribution. The powders perform high composition homogeneity and contain predominately supersaturated α 2-Ti3Al phase. The oxygen and carbon contents of the spheroidized powder are 0.47% and 0.050%, respectively.

  6. Microcrédits et performances financière et sociale des institutions de microfinance au Cameroun

    Directory of Open Access Journals (Sweden)

    Serge Messomo Ellé

    2017-09-01

    Full Text Available L’objectif de ce travail a été de déterminer les types de microcrédits qui expliquent les performances financière et sociale des institutions de microfinance au Cameroun (IMFs. Parmi les IMFs, 159 ont été analysées par le biais des statistiques descriptives et des équations de régression linéaire multiple. Les résultats obtenus montrent que les types d’activités financées expliquent faiblement les performances financière et sociale des IMFs au Cameroun. Par contre, les types de microcrédits accordés ont une forte emprise sur la viabilité financière et sociale de ces IMFs. Les implications managériales de ces résultats suggèrent aux IMFs d’accroître leurs performances financière et sociale au plan des types d’activités financées.

  7. Vertical and horizontal access configurations

    International Nuclear Information System (INIS)

    Spampinato, P.T.

    1987-01-01

    A number of configuration features and maintenance operations are influenced by the choice of whether a design is based on vertical or horizontal access for replacing reactor components. The features which are impacted most include the first wall/blanket segmentation, the poloidal field coil locations, the toroidal field coil number and size, access port size for in-vessel components, and facilities. Since either configuration can be made to work, the choice between the two is not clear cut because both have certain advantages. It is apparent that there are large cost benefits in the poloidal field coil system for ideal coil locations for high elongation plasmas and marginal savings for the INTOR case. If we assume that a new tokamak design will require a higher plasma elongation, the recommendation is to arrange the poloidal field coils in a cost-effective manner while providing reasonable midplane access for heating interfaces and test modules. If a new design study is not based on a high elongation plasma, it still appears prudent to consider this approach so that in-vessel maintenance can be accomplished without moving very massive structures such as the bulk shield. 10 refs., 29 figs., 3 tabs

  8. Horizontal vortex single chamber hydroturbine

    Directory of Open Access Journals (Sweden)

    Sergio Antonio Zarate-Orrego

    2016-01-01

    Full Text Available Se evaluó una máquina con alta resistencia de forma para extraer energía de una quebrada, río o corriente marina, y generar electricidad. Sin instrumentos adecuados, la investigación fue cualitativa. Se supuso que si aun así funcionaba, su comportamiento podía mejorar suavizándose la forma. El aparato tiene una tobera semi-convergente de paredes planas, una cámara de vórtice cilíndrica y un rodete. Capta agua por su sección mayor y la descarga tangencialmente por su sección menor en la cámara de vórtice; ésta tiene un orificio en una de sus paredes laterales. Así forma un vórtice horizontal que hace girar un rodete cuyo eje acciona un generador eléctrico. El trabajo experimental realizado mostró que sí es posible producir energía eléctrica con este dispositivo pese a las condiciones adversas en que se ensayó.

  9. Horizontal gene transfer between bacteria.

    Science.gov (United States)

    Heuer, Holger; Smalla, Kornelia

    2007-01-01

    Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

  10. Automation in tube finishing bay

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Satyadev, B.; Raghuraman, S.; Syama Sundara Rao, B.

    1997-01-01

    Automation concept in tube finishing bay, introduced after the final pass annealing of PHWR tubes resulted in integration of number of sub-systems in synchronisation with each other to produce final cut fuel tubes of specified length, tube finish etc. The tube finishing bay which was physically segregated into four distinct areas: 1. tube spreader and stacking area, 2. I.D. sand blasting area, 3. end conditioning, wad blowing, end capping and O.D. wet grinding area, 4. tube inspection, tube cutting and stacking area has been studied

  11. The Process of Horizontal Differentiation: Two Models.

    Science.gov (United States)

    Daft, Richard L.; Bradshaw, Patricia J.

    1980-01-01

    Explores the process of horizontal differentiation by examining events leading to the establishment of 30 new departments in five universities. Two types of horizontal differentiation processes--administrative and academic--were observed and each was associated with different organizational conditions. (Author/IRT)

  12. Horizontal drilling assessment in Western Canada

    International Nuclear Information System (INIS)

    Catania, Peter; Wilson, Malcolm

    1999-01-01

    The first horizontal well was drilled in Saskatchewan in 1987. Since then, the number of horizontal wells drilled has escalated rapidly, averaging approximately 500 per year since 1993. When combined with horizontal wells drilled in Alberta, the major Canadian oil-producing province, the total number drilled in 1995 was 978. This total exceeds the National Energy Board (NEB) projected maximum of 816 wells per year. The NEB projections were based on a break-even point for the drilling of horizontal wells of a return of CDN $285,000 using a discount rate of 15%. This corresponded to a cumulative production from each individual well of some 11,000 m 3 . The introduction of a royalty-free production volume of 12,000 m 3 per horizontal well in Saskatchewan was instrumental in stimulating the rapid expansion in the use of horizontal wells and helping Canada to exceed the forecasted drilling level. Within Saskatchewan, daily production from 1964 active horizontal wells is in excess of 20,000 m 3 . Comparative analysis indicates that the average daily production per well has increased from approximately by 40% with the advent of horizontal wells. In total production terms, provincial production has increased from 11.7 million cubic metres in 1989 to 20.9 million m 3 in 1996. This represents an increase of almost 79% based primarily on the extensive use of horizontal wells. In 1996, horizontal wells produced 36% of the province's oil from 12% of the active wells. In the southeastern producing areas of Saskatchewan, the Williston Basin, declining oil-production has jumped 100%, with horizontal wells accounting for approximately 50% of total regional production. Pay zones in this areas, as in most of the province, tend to be relatively thin, with net pay frequently less that 5 m. The modest investment of some CDN $5 million in government research funding 10 years ago to stimulate the development of horizontal wells, combined with a favourable royalty structure, has been at

  13. Piloting a Savings-Led Microfinance Intervention with Women Engaging in Sex Work in Mongolia: Further Innovation for HIV Risk Reduction

    Science.gov (United States)

    Tsai, Laura Cordisco; Witte, Susan S.; Aira, Toivgoo; Altantsetseg, Batsukh; Riedel, Marion

    2014-01-01

    This paper describes a pilot study testing the feasibility of an innovative savings-led microfinance intervention in increasing the economic empowerment and reducing the sexual risk behavior of women engaging in sex work in Mongolia. Women’s economic vulnerability may increase their risk for HIV by compromising their ability to negotiate safer sex with partners and heightening the likelihood they will exchange sex for survival. Microfinance has been considered a potentially powerful structural HIV prevention strategy with women conducting sex work, as diversification of income sources may increase women’s capacity to negotiate safer transactional sex. With 50% of all reported female HIV cases in Mongolia detected among women engaging in sex work, direct prevention intervention with women conducting sex work represents an opportunity to prevent a potentially rapid increase in HIV infection in urban Mongolia. The piloted intervention consisted of a matched savings program in which matched savings could be used for business development or vocational education, combined with financial literacy and business development training for women engaging in sex work. Results of the pilot demonstrate participants’ increased confidence in their ability to manage finances, greater hope for pursuing vocational goals, moderate knowledge gains regarding financial literacy, and an initial transition from sex work to alternative income generation for five out of nine participants. The pilot findings highlight the potential for such an intervention and the need for a clinical trial testing the efficacy of savings-led microfinance programs in reducing HIV risk for women engaging in sex work in Mongolia. PMID:24900163

  14. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  15. Steam generator tube performance

    International Nuclear Information System (INIS)

    Tatone, O.S.; Pathania, R.S.

    1982-04-01

    The performance of steam generator tubes in water-cooled nuclear power reactors has been reviewed for 1980. Tube defects occurred at 38% of the 97 reactors surveyed. This is a marginal improvement over 1979 when defects occurred at 41% of the reactors. The number of failed tubes was also lower, 0.14% of the tubes in service in 1980 compared with 0.20% of those in service in 1979. Analysis of the causes of these failures indicates that stress corrosion cracking was the leading failure mechanism. Reactors that used all-volatile treatment of secondary water, with or without full-flow condensate demineralization since start-up showed the lowest incidence of corrosion-related defects

  16. X-ray tube

    International Nuclear Information System (INIS)

    Webley, R.S.

    1975-01-01

    The object of the invention described is to provide an X-ray tube providing a scanned X-ray output which does not require a scanned electron beam. This is obtained by an X-ray tube including an anode which is rotatable about an axis, and a source of a beam of energy, for example an electron beam, arranged to impinge on a surface of the anode to generate X-radiation substantially at the region of incidence on the anode surface. The anode is rotatable about the axis to move the region of incidence over the surface. The anode is so shaped that the rotation causes the region of incidence to move in a predetermined manner relative to fixed parts of the tube so that the generated X-radiation is scanned in a predetermined manner relative to the tube. (UK)

  17. Fuel assembly guide tube

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1979-01-01

    This invention is directed toward a nuclear fuel assembly guide tube arrangement which restrains spacer grid movement due to coolant flow and which offers secondary means for supporting a fuel assembly during handling and transfer operations

  18. Bull Moose Tube Company

    Science.gov (United States)

    The EPA is providing notice of a proposed Administrative Penalty Assessment against the Bull Moose Tube Company, a business located at 1819 Clarkson Road, Chesterfield, MO, 63017, for alleged violations at the facility located at 406 East Industrial Drive,

  19. Tracheostomy tube - eating

    Science.gov (United States)

    Trach - eating ... take your first bites. Certain factors may make eating or swallowing harder, such as: Changes in the ... easier to swallow. Suction the tracheostomy tube before eating. This will keep you from coughing while eating, ...

  20. Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen

    2005-08-29

    This report describes a three-year project to investigate the major factors of horizontal heat exchanger performance in passive containment heat removal from a light water reactor following a design basis accident LOCA (Loss of Coolant Accident). The heat exchanger studied in this work may be used in advanced and innovative reactors, in which passive heat removal systems are adopted to improve safety and reliability The application of horizontal tube-bundle condensers to passive containment heat removal is new. In order to show the feasibility of horizontal heat exchangers for passive containment cooling, the following aspects were investigated: 1. the condensation heat transfer characteristics when the incoming fluid contains noncondensable gases 2. the effectiveness of condensate draining in the horizontal orientation 3. the conditions that may lead to unstable condenser operation or highly degraded performance 4. multi-tube behavior with the associated secondary-side effects This project consisted of two experimental investigations and analytical model development for incorporation into industry safety codes such as TRAC and RELAP. A physical understanding of the flow and heat transfer phenomena was obtained and reflected in the analysis models. Two gradute students (one funded by the program) and seven undergraduate students obtained research experience as a part of this program.

  1. Streak tube development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of a high-speed, high-resolution streak image tube is described. This is one task in the development of a streak camera system with digital electronic readout, whose primary application is for diagnostics in underground nuclear testing. This program is concerned with the development of a high-resolution streak image tube compatible with x-ray input and electronic digital output. The tube must be capable of time resolution down to 100 psec and spatial resolution to provide greater than 1000 resolution elements across the cathode (much greater than presently available). Another objective is to develop the capability to make design changes in tube configurations to meet different experimental requirements. A demountable prototype streak tube was constructed, mounted on an optical bench, and placed in a vacuum system. Initial measurements of the tube resolution with an undeflected image show a resolution of 32 line pairs per millimeter over a cathode diameter of one inch, which is consistent with the predictions of the computer simulations. With the initial set of unoptmized deflection plates, the resolution pattern appeared to remain unchanged for static deflections of +- 1/2-inch, a total streak length of one inch, also consistent with the computer simulations. A passively mode-locked frequency-doubled dye laser is being developed as an ultraviolet pulsed light source to measure dynamic tube resolution during streaking. A sweep circuit to provide the deflection voltage in the prototype tube has been designed and constructed and provides a relatively linear ramp voltage with ramp durations adjustable between 10 and 1000 nsec

  2. Researching YouTube

    OpenAIRE

    Arthurs, Jane; Drakopoulou, Sophia; Gandini, Alessandro

    2018-01-01

    ‘Researching YouTube’ introduces the special issue of Convergence which arose out of an international academic conference on YouTube that was held in London at Middlesex University in September 2016. The conference aimed to generate a robust overview of YouTube’s changing character and significance after its first ten years of development by creating a productive dialogue between speakers from different disciplines and cultures, and between YouTube-specific research and wider debates in media...

  3. Tubing crimping pliers

    Science.gov (United States)

    Lindholm, G.T.

    1981-02-27

    The disclosure relates to pliers and more particularly to pliers for crimping two or more pieces of copper tubing together prior to their being permanently joined by brazing, soldering or the like. A die containing spring-loaded pins rotates within a cammed ring in the head of the pliers. As the die rotates, the pins force a crimp on tubing held within the pliers.

  4. Importance of drill string assembly swivel in horizontal drilling

    Directory of Open Access Journals (Sweden)

    Edmund Tasak

    2006-10-01

    Full Text Available A part of the drill string – the swivel (rotational connector – accomplishes an important task in the horizontal drilling. Its malfunctioning makes it impossible to draw in ( install large diameter and length pipelines. The causes of the connector break-down during the horizontal drilling are investigated in the paper. The drilling has been made for twenty inches gas pipeline installation during reaming operations. A trouble was encountered making good work conditions of a system consisting of the drilling machine drill string reamer swivel tube shield of Cardan joint and the gas pipeline 500 m long. In this case, the swivel brokes down and the planned operation was not finished. The assessment of improper drilling conditions, selection of operation system components, and drilling parameters and the insufficient technological supervising have created an excessive risk of failure. A proper application of technical analysis would considerably decrease the hazard of failure which cause large costs, delays and decrease of confidence to the drilling contractor and pipeline installation.

  5. Pressure tube reactor

    International Nuclear Information System (INIS)

    Seki, Osamu; Kumasaka, Katsuyuki.

    1988-01-01

    Purpose: To remove the heat of reactor core using a great amount of moderators at the periphery of the reactor core as coolants. Constitution: Heat of a reactor core is removed by disposing a spontaneous recycling cooling device for cooling moderators in a moderator tank, without using additional power driven equipments. That is, a spontaneous recycling cooling device for cooling the moderators in the moderator tank is disposed. Further, the gap between the inner wall of a pressure tube guide pipe disposed through the vertical direction of a moderator tank and the outer wall of a pressure tube inserted through the guide pipe is made smaller than the rupture distortion caused by the thermal expansion upon overheating of the pressure tube and greater than the minimum gap required for heat shiels between the pressure tube and the pressure tube guide pipe during usual operation. In this way, even if such an accident as can not using a coolant cooling device comprising power driven equipment should occur in the pressure tube type reactor, the rise in the temperature of the reactor core can be retarded to obtain a margin with time. (Kamimura, M.)

  6. Research on horizontal displacement monitoring of deep soil based on a distributed optical fibre sensor

    Science.gov (United States)

    Huang, Xiaodi; Wang, Yuan; Sun, Yangyang; Zhang, Qinghua; Zhang, Zhenglin; You, Zewei; Ma, Yuan

    2018-01-01

    The traditional measurement method for the horizontal displacement of deep soil usually uses an inclinometer for piecewise measurement and then generates an artificial reading, which takes a long time and often contains errors; in addition, the anti-jamming and long-term stability of the inclinometer is poor. In this paper, a technique for monitoring horizontal displacement based on distributed optical fibres is introduced. The relationship between the strain and the deflection was described by a theoretical model, and the strain distribution of the inclinometer tube was measured by the cables laid on its surface so that the deflection of the inclinometer tube could be calculated by the difference algorithm and regarded as the horizontal displacement of deep soil. The horizontal displacement monitoring technology of deep soil based on distributed optical fibre sensors developed in this paper not only overcame the shortcomings of traditional inclinometer technology to realize automatic real-time monitoring but also allowed for distributed measurement. The experiment was similar to the expected engineering situations, and the deflection calculated from the strain was compared with an inclinometer. The results demonstrated that the relative error between the distributed optical fibre sensors and the inclinometer was less than 8.0%, and the results also verified both the feasibility of using distributed optical fibre to monitor the horizontal displacement of soil as well as the rationality of the theoretical model and difference algorithm. The application of distributed optical fibre in monitoring the horizontal displacement of deep soil in the engineering of foundation pits and slopes can more accurately evaluate the safety of engineering during construction.

  7. Tube spacer grid for a heat-exchanger tube bundle

    International Nuclear Information System (INIS)

    Scheidl, H.

    1976-01-01

    A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

  8. Investigations of post-dryout heat transfer in case of vertical and horizontal pipe flow

    International Nuclear Information System (INIS)

    Schnittger, R.B.

    1982-01-01

    Experimental studies are presented of the heat transfer behaviour of a post dry-out flows in directly heated tubes of 6 m length. The wall temperatures of the tube are measured by thermocouples, which are distributed radially and axially on the outer tube surface. The vapor temperature is determined by a probe at the exit of the tube R 12 is used as a working fluid. Based on the experimental temperature distribution, the influence on pressure, massflow-density, and on specific thermal surface load had been studied. As a result, the heat transfer behaviour is dominated in a broad parameter range by thermal non-equilibrium conditions between the phases. Under these conditions the heat is transfered mainly from the tube wall to the vapor and from the vapor to the droplets. The strong wall temperature decrease observed at higher pressures and specific thermal surface loads after the dryout is not explained by a contact between the droplets and the tube wall, but by the decay of the droplets in the boundary layer of the wall. The non-uniform wall-temperature distribution of the horizontal tube and the lower evaporation rate compared with a vertical tube are explained by a non-uniform vapor temperature - and droplet distribution over the tube cross-section. A model is proposed for the calculation of the wall temperatures, which accounts for all these individual effects. This model can also be applied in the case of water as is demonstrated by a comparison with respective experimental results from the literature. (orig.) [de

  9. Numerical Simulation and Optimization of the Melting Process of Phase Change Material inside Horizontal Annulus

    Directory of Open Access Journals (Sweden)

    Saiwei Li

    2017-08-01

    Full Text Available Latent heat storage (LHS technologies adopting phase change materials (PCMs are increasingly being used to bridge the spatiotemporal mismatch between energy production and demand, especially in industries like solar power, where strong cyclic fluctuations exist. The shell-and-tube configuration is among the most prevalent ones in LHS and thus draws special attention from researchers. This paper presents numerical investigations on the melting of PCM, a paraffin blend RT27, inside a horizontal annulus. The volume of fluid model was adopted to permit density changes with the solidification/melting model wherein natural convection was taken into account. The eccentricity and diameter of the inner tube, sub-cooling degree of the PCM, and the heating-surface temperature were considered as variables for study. Through the evaluation of the melting time and exergy efficiency, the optimal parameters of the horizontal annulus were obtained. The results showed that the higher the heating boundary temperature, the earlier the convection appeared and the shorter the melting time. Also, the different eccentricity and diameters of the inner tube influenced the annulus tube interior temperature distribution, which in turn determined the strength and distribution of the resulting natural convection, resulting in varying melting rates.

  10. Eddy current proximity measurement of perpendicular tubes from within pressure tubes in CANDU nuclear reactors

    Science.gov (United States)

    Bennett, P. F. D.; Underhill, P. R.; Morelli, J.; Krause, T. W.

    2018-04-01

    Fuel channels in CANDU® (CANada Deuterium Uranium) nuclear reactors consist of two non-concentric tubes; an inner pressure tube (PT) and a larger diameter calandria tube (CT). Up to 400 horizontally mounted fuel channels are contained within a calandria vessel, which also holds the heavy water moderator. Certain fuel channels pass perpendicularly over horizontally oriented tubes (nozzles) that are part of the reactor's liquid injection shutdown system (LISS). Due to sag, these fuel channels are at risk of coming into contact with the LISS nozzles. In the event of contact between the LISS nozzle and CT, flow-induced vibrations from within the moderator could lead to fretting and deformation of the CT. LISS nozzle proximity to CTs is currently measured optically from within the calandria vessel, but from outside the fuel channels. Measurement by an independent means would provide confidence in optical results and supplement cases where optical observations are not possible. Separation of PT and CT, known as gap, is monitored from within the PT using a transmit-receive eddy current probe. Investigation of the eddy current based gap probe as a tool to also measure proximity of LISS nozzles was carried out experimentally in this work. Eddy current response as a function of LISS-PT proximity was recorded. When PT-CT gap, PT wall thickness, PT resistivity and probe lift-off variations were not present this dependence could be used to determine the LISS-PT proximity. This method has the potential to provide LISS-CT proximity using existing gap measurement data. Obtaining LISS nozzle proximity at multiple inspection intervals could be used to provide an estimate of the time to LISS-CT contact, and thereby provide a means of optimizing maintenance schedules.

  11. Experimental verification of the horizontal steam generator boil-off transfer degradation at natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Hyvaerinen, J. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Kouhia, J. [VTT Energy, Lappeenranta (Finland)

    1997-12-31

    The presentation summarises the highlights of experimental results obtained for VVER type horizontal steam generator heat transfer, primary side flow pattern, and mixing in the hot collector during secondary side boil-off with primary at single-phase natural circulation. The experiments were performed using the PACTEL facility with Large Diameter (LD) steam generator models, with collector instrumentation designed specifically for these tests. The key findings are as follows: (1) the primary to secondary heat transfer degrades as the secondary water inventory is depleted, following closely the wetted tube area; (2) a circulatory flow pattern exists in the tube bundle, resulting in reversed flow (from cold to the hot collector) in the lower part of the tube bundle, and continuous flow through the upper part, including the tubes that have already dried out; and (3) mixing of the hot leg flow entering the hot collector and reversed, cold, tube flow remains confined within the collector itself, extending only a row or two above the elevation at which tube flow reversal has taken place. 6 refs.

  12. Experimental verification of the horizontal steam generator boil-off transfer degradation at natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Hyvaerinen, J [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Kouhia, J [VTT Energy, Lappeenranta (Finland)

    1998-12-31

    The presentation summarises the highlights of experimental results obtained for VVER type horizontal steam generator heat transfer, primary side flow pattern, and mixing in the hot collector during secondary side boil-off with primary at single-phase natural circulation. The experiments were performed using the PACTEL facility with Large Diameter (LD) steam generator models, with collector instrumentation designed specifically for these tests. The key findings are as follows: (1) the primary to secondary heat transfer degrades as the secondary water inventory is depleted, following closely the wetted tube area; (2) a circulatory flow pattern exists in the tube bundle, resulting in reversed flow (from cold to the hot collector) in the lower part of the tube bundle, and continuous flow through the upper part, including the tubes that have already dried out; and (3) mixing of the hot leg flow entering the hot collector and reversed, cold, tube flow remains confined within the collector itself, extending only a row or two above the elevation at which tube flow reversal has taken place. 6 refs.

  13. Experimental verification of the horizontal steam generator boil-off transfer degradation at natural circulation

    International Nuclear Information System (INIS)

    Hyvaerinen, J.; Kouhia, J.

    1997-01-01

    The presentation summarises the highlights of experimental results obtained for VVER type horizontal steam generator heat transfer, primary side flow pattern, and mixing in the hot collector during secondary side boil-off with primary at single-phase natural circulation. The experiments were performed using the PACTEL facility with Large Diameter (LD) steam generator models, with collector instrumentation designed specifically for these tests. The key findings are as follows: (1) the primary to secondary heat transfer degrades as the secondary water inventory is depleted, following closely the wetted tube area; (2) a circulatory flow pattern exists in the tube bundle, resulting in reversed flow (from cold to the hot collector) in the lower part of the tube bundle, and continuous flow through the upper part, including the tubes that have already dried out; and (3) mixing of the hot leg flow entering the hot collector and reversed, cold, tube flow remains confined within the collector itself, extending only a row or two above the elevation at which tube flow reversal has taken place

  14. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home >> NEI YouTube Videos >> NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  15. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... search for current job openings visit HHS USAJobs Home » NEI YouTube Videos » NEI YouTube Videos: Amblyopia Listen NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia Animations Blindness Cataract ...

  16. PACTEL: Experiments on the behaviour of the new horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Kouhia, J.; Riikonen, V.; Purhonen, H. [VTT Energy, Lappeenranta (Finland)

    1995-12-31

    Experiments were performed to study the behaviour of the PACTEL facility, a medium scale integral test loop simulating VVER 440 pressurized water reactors. The study focused on the operation of the new horizontal steam generator model installed in PACTEL. Three experiments were conducted: a small-break test to observe the steam generator behaviour over a range of primary coolant inventories, a hot leg loop seal experiment to study the cyclic behaviour of a loop seal and a loss of secondary side feedwater test to examine the effect of uncovered tubes in the steam generator. A reverse flow was observed in the lower part of the U-tube bundle of the steam generator during natural circulation. The flow reversal point dropped when the tubes uncovered, during secondary inventory reduction. (orig.). 5 refs.

  17. PACTEL: Experiments on the behaviour of the new horizontal steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Kouhia, J; Riikonen, V; Purhonen, H [VTT Energy, Lappeenranta (Finland)

    1996-12-31

    Experiments were performed to study the behaviour of the PACTEL facility, a medium scale integral test loop simulating VVER 440 pressurized water reactors. The study focused on the operation of the new horizontal steam generator model installed in PACTEL. Three experiments were conducted: a small-break test to observe the steam generator behaviour over a range of primary coolant inventories, a hot leg loop seal experiment to study the cyclic behaviour of a loop seal and a loss of secondary side feedwater test to examine the effect of uncovered tubes in the steam generator. A reverse flow was observed in the lower part of the U-tube bundle of the steam generator during natural circulation. The flow reversal point dropped when the tubes uncovered, during secondary inventory reduction. (orig.). 5 refs.

  18. Tube plug removal machine

    International Nuclear Information System (INIS)

    Hawkins, P.J.

    1987-01-01

    In a nuclear steam generator wherein some faulty tubes have been isolated by mechanical plugging, to remove a selected plug without damaging the associated tube, a plug removal machine is used. The machine drills into a plug portion with a tap drill bit having a drill portion a tap portion and a threaded portion, engaging that plug portion with the threaded portion after the drilled hole has been threaded by the tap portion thereof, and removing a portion of the plug in the tube with a counterbore drill bit mounted concentrically about the tap drill bit. A trip pin and trip spline disengage the tap drill bit from the motor. The counterbore drill bit is thereafter self-centered with respect to the tube and plug about the now stationary tap drill bit. After a portion of the plug has been removed by the counterbore drill bit, pulling on the top drill bit by grippers on slots will remove the remaining plug portion from the tube. (author)

  19. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  20. Measuring of tube expansion

    International Nuclear Information System (INIS)

    Vogeleer, J. P.

    1985-01-01

    The expansion of the primary tubes or sleeves of the steam generator of a nuclear reactor plant are measured while the tubes or sleeves are being expanded. A primary tube or sleeve is expanded by high pressure of water which flows through a channel in an expander body. The water is supplied through an elongated conductor and is introduced through a connector on the shank connected to the conductor at its outer end. A wire extends through the mandrel and through the conductor to the end of the connector. At its inner end the wire is connected to a tapered pin which is subject to counteracting forces produced by the pressure of the water. The force on the side where the wire is connected to the conductor is smaller than on the opposite side. The tapered pin is moved in the direction of the higher force and extrudes the wire outwardly of the conductor. The tapered surface of the tapered pin engages transverse captive plungers which are maintained in engagement with the expanding tube or sleeve as they are moved outwardly by the tapered pin. The wire and the connector extend out of the generator and, at its outer end, the wire is connected to an indicator which measures the extent to which the wire is moved by the tapered pin, thus measuring the expansion of the tube or sleeve as it progresses