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Papers by upendra pratap singh

International Journal of Food Engineering, 2008

The study investigated the effect of different pretreatments such as citric-acid (CA), potassiumm... more The study investigated the effect of different pretreatments such as citric-acid (CA), potassiummetabisulphite (KMS), and ethylenediamine-tetraacetic acid (EDTA) on the drying kinetics, allicin and colour of garlic slices in a convective hot-air dryer at temperatures of 45, 50 and 55°C. The allicin content of the fresh garlic slices compared with the dried slices increased non-linearly with increase in temperature from 8.6 to 23.5, 13.3 to 22.4, 11.9 to 23.4 and 12.3 to 24.1 µg/ml for the control, CA, KMS, and EDTA samples, respectively. The drying characteristics were evaluated against Page et al. (1949) mathematical models on the basis of the coefficient of determination (R 2 ), reduced chi-square ( 2 χ ), and root mean square error (RMSE). The drying characteristics of garlic slices of the control were best described by the Midilli et al. (2002) model whilst the CA, KMS, and EDTA pretreated samples were best described by the Henderson and Pabis (2006) model within the confines of the experiments. The colour of the fresh and dried garlic slices were measured in Hunter parameters. The KMS pretreated samples showed greatest brightness (85.95) and least redness (1.36) in colour at 50°C and 45, respectively compared with the fresh, whereas the EDTA pretreated samples were yellower (17.43) at 45°C.

Observations of discharge, temperature and suspended sediment made at a gauging site established ... more Observations of discharge, temperature and suspended sediment made at a gauging site established near the snout of the Dokriani glacier in the western Himalayan region are presented. These observations were made during a scientific expedition to this glacier over 21 days (23.8.1992-12.9.1992). Because of harsh weather conditions, observations could not be made for a longer period. The minimum streamflow in the glacier melt stream was observed at 0700 h whereas the maximum was observed at 1800 h. The ratio of maximum to minimum flow was computed to be 1.81 from the continuous hourly observations. Based on an analysis of the recession of the hydrograph, it was found that the meltwater time lag from the accumulation zone of the glacier was more than seven times higher than that from the ablation zone. No specific relationship was observed between suspended sediment and discharge. The average values of the suspended sediment concentration and load were found to be 350 ppm and 180 t day" 1 , respectively, for the study period. Weathering processes in different zones of the glacier were also studied to find out the source of the sediment transported by the meltwater into the melt stream. A high correlation coefficient (r = 0.89) was found between the glacier specific runoff and the air temperature at the gauging site. It showed that temperature alone can represent the melting of the glacier and may be considered for the hydrological modelling of glacier melt runoff. Based on observations over three days under clear weather conditions for isolated snow blocks, the average snowmelt factor was computed to be 5.4 mm /(°C. 6 h).

Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 1995

Observations of discharge, temperature and suspended sediment made at a gauging site established ... more Observations of discharge, temperature and suspended sediment made at a gauging site established near the snout of the Dokriani glacier in the western Himalayan region are presented. These observations were made during a scientific expedition to this glacier over 21 days (23.8.1992-12.9.1992). Because of harsh weather conditions, observations could not be made for a longer period. The minimum streamflow in the glacier melt stream was observed at 0700 h whereas the maximum was observed at 1800 h. The ratio of maximum to minimum flow was computed to be 1.81 from the continuous hourly observations. Based on an analysis of the recession of the hydrograph, it was found that the meltwater time lag from the accumulation zone of the glacier was more than seven times higher than that from the ablation zone. No specific relationship was observed between suspended sediment and discharge. The average values of the suspended sediment concentration and load were found to be 350 ppm and 180 t day" 1 , respectively, for the study period. Weathering processes in different zones of the glacier were also studied to find out the source of the sediment transported by the meltwater into the melt stream. A high correlation coefficient (r = 0.89) was found between the glacier specific runoff and the air temperature at the gauging site. It showed that temperature alone can represent the melting of the glacier and may be considered for the hydrological modelling of glacier melt runoff. Based on observations over three days under clear weather conditions for isolated snow blocks, the average snowmelt factor was computed to be 5.4 mm /(°C. 6 h).

International Journal of Food Engineering, 2008

The study investigated the effect of different pretreatments such as citric-acid (CA), potassiumm... more The study investigated the effect of different pretreatments such as citric-acid (CA), potassiummetabisulphite (KMS), and ethylenediamine-tetraacetic acid (EDTA) on the drying kinetics, allicin and colour of garlic slices in a convective hot-air dryer at temperatures of 45, 50 and 55°C. The allicin content of the fresh garlic slices compared with the dried slices increased non-linearly with increase in temperature from 8.6 to 23.5, 13.3 to 22.4, 11.9 to 23.4 and 12.3 to 24.1 µg/ml for the control, CA, KMS, and EDTA samples, respectively. The drying characteristics were evaluated against Page et al. (1949) mathematical models on the basis of the coefficient of determination (R 2 ), reduced chi-square ( 2 χ ), and root mean square error (RMSE). The drying characteristics of garlic slices of the control were best described by the Midilli et al. (2002) model whilst the CA, KMS, and EDTA pretreated samples were best described by the Henderson and Pabis (2006) model within the confines of the experiments. The colour of the fresh and dried garlic slices were measured in Hunter parameters. The KMS pretreated samples showed greatest brightness (85.95) and least redness (1.36) in colour at 50°C and 45, respectively compared with the fresh, whereas the EDTA pretreated samples were yellower (17.43) at 45°C.

Observations of discharge, temperature and suspended sediment made at a gauging site established ... more Observations of discharge, temperature and suspended sediment made at a gauging site established near the snout of the Dokriani glacier in the western Himalayan region are presented. These observations were made during a scientific expedition to this glacier over 21 days (23.8.1992-12.9.1992). Because of harsh weather conditions, observations could not be made for a longer period. The minimum streamflow in the glacier melt stream was observed at 0700 h whereas the maximum was observed at 1800 h. The ratio of maximum to minimum flow was computed to be 1.81 from the continuous hourly observations. Based on an analysis of the recession of the hydrograph, it was found that the meltwater time lag from the accumulation zone of the glacier was more than seven times higher than that from the ablation zone. No specific relationship was observed between suspended sediment and discharge. The average values of the suspended sediment concentration and load were found to be 350 ppm and 180 t day" 1 , respectively, for the study period. Weathering processes in different zones of the glacier were also studied to find out the source of the sediment transported by the meltwater into the melt stream. A high correlation coefficient (r = 0.89) was found between the glacier specific runoff and the air temperature at the gauging site. It showed that temperature alone can represent the melting of the glacier and may be considered for the hydrological modelling of glacier melt runoff. Based on observations over three days under clear weather conditions for isolated snow blocks, the average snowmelt factor was computed to be 5.4 mm /(°C. 6 h).

Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 1995

Observations of discharge, temperature and suspended sediment made at a gauging site established ... more Observations of discharge, temperature and suspended sediment made at a gauging site established near the snout of the Dokriani glacier in the western Himalayan region are presented. These observations were made during a scientific expedition to this glacier over 21 days (23.8.1992-12.9.1992). Because of harsh weather conditions, observations could not be made for a longer period. The minimum streamflow in the glacier melt stream was observed at 0700 h whereas the maximum was observed at 1800 h. The ratio of maximum to minimum flow was computed to be 1.81 from the continuous hourly observations. Based on an analysis of the recession of the hydrograph, it was found that the meltwater time lag from the accumulation zone of the glacier was more than seven times higher than that from the ablation zone. No specific relationship was observed between suspended sediment and discharge. The average values of the suspended sediment concentration and load were found to be 350 ppm and 180 t day" 1 , respectively, for the study period. Weathering processes in different zones of the glacier were also studied to find out the source of the sediment transported by the meltwater into the melt stream. A high correlation coefficient (r = 0.89) was found between the glacier specific runoff and the air temperature at the gauging site. It showed that temperature alone can represent the melting of the glacier and may be considered for the hydrological modelling of glacier melt runoff. Based on observations over three days under clear weather conditions for isolated snow blocks, the average snowmelt factor was computed to be 5.4 mm /(°C. 6 h).