Singh Model Research Articles

The Experiences of Muslim American Military Personnel Serving in the U.S. Military

Results of our grounded theory exploration of the experiences of Muslim American military personnel (MAMP; N = 13) resulted in a model of discrimination and resiliency in Muslim American military personnel (DaRMAMP). DaRMAMP extends Loo, Singh, Scurfield, and Kilauno's (1998) model of race-related stress through its focus on discrimination and resilience in multiple contexts (e.g., in the military as well as in the Muslim American civilian and American civilian communities). Practical applications involve intentional areas of inquiry regarding effects of discrimination and resiliency resources during psychological intervention and opportunities for psychoeducation.

Analysis of convective drying kinetics of yellow passion fruit bagasse

This study aimed to analyze the convective drying in fixed bed of yellow passion fruit bagasse. Firstly, the initial moisture of the bagasse was determined in stove, at 105 ± 3oC for 24 hours. In the drying tests, it was collected the bagasse mass values over time, by using a convective dryer, operated at four temperatures (35, 45, 55 and 65oC) and three air flow speeds at 0.8, 1.0 and 1.3 m s -1 . Having the curves of the drying and of drying rates, it was observed that the temperature had a great influence on the bagasse drying, since as the temperature increases, the drying time is shortened, increasing thus the drying rate. The curves of drying and of drying rate were fitted to the models proposed by Page (1949 apud MOTTA LIMA et al., 2003)and Motta Lima et al. (2002), and the models set by Hogdes (1982) and Toffoli (2005 apud SANTOS et al., 2008), respectively. Other mathematical models were also fitted for each drying process, such as: Simple Exponential, Page, Henderson and Pabis, Logarithm, two-term exponential model, and Wang and Singh model. The best model was chosen by analysis of the highest R² and F-test, and the lowest root mean square error.

DEVELOPMENT OF A REFRIGERATION SYSTEM FOR COOLING MILK AT RURAL REGIONS

The present paper presents an experimental evaluation of a solar refrigerator, prototype, based on an intermittent thermodynamic cycle of adsorption, using milk as refrigerant and the mineral zeolite as adsorber. This system uses a mobile adsorber, which is regenerated out of the refrigeration cycle and no condenser is applied. Because the solar regeneration is made in the ambient air for the regeneration, a SK14 solar cooker is considered. The cold chamber, with a capacity of 4 liters, is aimed for cooling milk. The objective is to analyze the advantages and disadvantages of the eventual use of this refrigerator in rural regions of Egypt, where no electricity is available. On the bases of the results obtained, a new prototype of refrigerator for rural regions is designed, based on the same thermodynamic cycle, but including changes in design and operation. According to the experiments Zeolite pan size of 2*20*25 cm proved to be the most optimum, it is the size recommended for use in milk cooler. According to the results of the mathematical modeling of drying of zeolite, the best describing the drying characteristic is Wang and Singh model. The regression equation R (correlation coefficient) indicates the degree of association between the observed and predicted values coefficient of efficient (Ce) was 0.999.

Stability of nanopore formation in aluminum anodization in oxalic acid

The effect of applied voltage on nanopore formation stability of porous anodized alumina (PAA) in oxalic acid electrolyte was investigated. The Al anodization at a constant applied voltage is a popular electrochemical method to synthesize PAA templates. The experimental observations of Al anodization are used to compare the predictions of the THAMIDA model for interpore distance and the stability criterion of the SINGH model. It is found that, in the electrolyte of pH = 0.96, the interpore distance—applied voltage has a linear dependence coefficient of 2.24 nm/V, which agrees well with the THAMIDA model. It has also been confirmed that pore formation is instable at above 60 V which can be predicted by SINGH model. A second unstable growth regime below 30 V is also observed, which is not predicted by any of the models.

Optimization and kinetic studies on treatment of textile dye wastewater using Pleurotus floridanus

Treatment of textile dye wastewater was carried using Pleurotus floridanus in a batch reactor. Response surface methodology (RSM) was used to optimize the process parameters like pH, temperature, agitation speed and dye wastewater concentration for the decolorization of textile dye wastewater. The optimum conditions for the maximum decolorization was: pH 6.6, temperature 28.8 °C, agitation speed 183 rpm and dye wastewater concentration 1:2. From the results it was found that, the linear effect of agitation speed and initial textile dye wastewater concentration were more significant than other factors for the textile dye wastewater treatment. At these optimized conditions, the maximum decolorization and COD reduction was found to be 71.2 and 80.5 %, respectively. Kinetics of textile dye degradation process was studied by various models like first order, diffusional and Singh model. From the results it was found that the degradation follows first order model with R2 value of 0.9550.

Foam Mat Drying Characteristics of Mango Pulp

Mango is widely preferred because of its excellent flavour and nutritional quality. Mango pulp fro m Dussehri variety was foam mat d ried using 0, 3, 5, 7, and 9% egg white as foaming agent and then dried at air dry ing temperature of 65, 75 and 85 o C. Weight loss was used to estimate change in mo iture ratio with respect to time and effective diffusivity. Seven thin layer drying models were fitted to get the best fit model, which was selected on the basis of various statistical parameters. Wang and Singh model was found to be best in almost all cases. Nutrit ional status in terms of total carotenes was estimated and it was observed that there was significant effect of drying temperatures and egg white concentration. Based on above parametres it was resolved that foam mat d rying using 3% egg white at 65 o C air dry ing temperature was the best combination.

Creep behavior of EPS composite soil

EPS composite soil is one type of premixed lightweight fills studied by numerous researchers. However, one aspect that has not been fully understood is the creep behaviors which may have significant effect on the design and application of EPS composite soil. In this paper, the results of a series of oedometer creep tests and triaxial undrained creep tests on EPS composite soil were presented. Four main influencing factors were identified and their effects on the creep behaviors of EPS composite soil were studied. Three well established creep models, namely, Findley model, Singh & Mitchell model, and Mesri model, were used to simulate the creep behavior of EPS composite soil. This study shows that the Findley creep model fits the test results the best. A semi-empirical creep model was also proposed to model the creep behavior under axisymmetric conditions. In this model, the creep strain was divided into instant and viscous elastic strain as well as instant and viscous plastic strain which were simulated by element models and empirical equations, respectively. It was shown that the proposed creep model was able to precisely predict the creep strain of EPS composite soil.

Mathematical Models’ Establishment of Hot-Air Drying for Spratelloides gracilis

An electric heat blast dryer was constructed to carry out thin layer drying studies of Spratelloides gracilis at the temperatures of 60, 70, and 80°C and the air velocity of 1.00 ± 0.07 m/s. Strong quadratic dependence between drying rate and drying time (R 2 > 0.967) was found. The effective water diffusivity and dry basis moisture content showed a good linear relationship (R 2 > 0.998). Furthermore, out of the nine models considered, the Wang and Singh model was found to be the most suitable for describing the drying behavior of Spratelloides gracilis with the highest value for coefficient of determination (R 2), the lowest value for chi-square (χ2), root-mean-square error (RMSE), and mean relative percent error (PE). The activation energy of the sample was 20.9796 kJ/mol.

Biodegradation and decolourization of textile dye wastewater using Ganoderma lucidum.

In this work, treatment of textile dye wastewater was carried in a batch reactor using Ganoderma lucidum. The characteristics of textile dye wastewater were studied. The effect of process parameters like pH, temperature, agitation speed and dye wastewater concentration on dye decolourization and degradation were studied. These parameters were optimized using response surface methodology (RSM). From the results, the optimized conditions were: pH 6.6, temperature 26.5 °C, agitation speed 200 rpm and dye wastewater concentration 1:2. At these optimized conditions, the maximum decolourization and COD reduction were found to be 81.4 and 90.3 %. Kinetic studies were carried out using different models like first-order, diffusional and Singh model. From the results, it was found that the degradation follows the first-order reaction model.

Characterisation of volatiles in dried white varieties figs (Ficus carica L.).

The aromatic profile of volatiles in dried figs varieties Bružetka Bijela and Zimnica were characterised by headspace solid-phase (HS-SPME) procedure with gas chromatography-mass spectrometry analysis (GC-MS). The volatile compounds were distributed by distinct chemical classes, including alcohols, aldehydes, esters, terpenic compounds, and other compounds. The figs were dried in a pilot plant cabinet dryer. Prior to drying process, figs were pre-treated by sulphur dioxide, immersed in solution of citric acid and ascorbic acid, respectively. Several mathematical thin-layer drying models, available in the literature, were fitted to experimental data of figs, implementing non-linear regression analysis techniques. The results showed that pre-treatments of figs decrease significantly the drying time. The best thin-layer drying model in terms of fitting performance was Wang and Singh model. The major volatile compound in dried figs was benzaldehyde. After benzaldehyde, the most abundant aldehyde in dried figs was hexanal. The comparison among dried figs showed the highest abundance of aldehydes, in general, in non-treated (control) dried figs compared to pre-treated samples. Furthermore, ascorbic acid was the most efficient in preserving esters and alcohols in case of Bružetka Bijela, whereas in case of Zimnica, sulphur dioxide was in advance compared to ascorbic acid. Ethyl acetate was the most abundant ester found in dried figs. Among other compounds, 2-butanone,3-hydroxy was the most abundant identified volatiles. Linalool, as the only identified terpen, was in case of both dried fig varieties, preserved by immersion into ascorbic acid. The immersion into citric acid has not been so successful in volatiles conservation.

Performance evaluation of modified versions of SCS curve number method for two watersheds of Maharashtra, India

One of the popular methods for computing the depth of surface runoff for a given rainfall event is the Soil Conservation Service Curve Number (SCS-CN) method. Research conducted on the applicability of the SCS-CN method suggested a need for improvement. Consequently, several modifications of the method have been suggested and reported in literature. The important modified versions of the method include Mishra and Singh (MS) model, Michel et al. model, Sahu et al. model and SME model. These modified models have been reported to perform better than the original method for U.S. watersheds. In the present study, these modified models are applied to two Indian watersheds in Maharashtra and are compared with each other for their performance. The results indicated that the SME and the Sahu et al. model perform equally well compared to each other, and the duo perform consistently better than the original SCS-type method and the others for both the Amba and Kalu watersheds. Further, the performance of the MS model is found to be better than the Michel et al. model.

An alternative randomized response model using two decks of cards

In an attempt to obtain trustworthy answers from the respondents regarding a sensitive question in order to estimate the population proportion possessing that sensitive attribute, Odumade and Singh (2009) have suggested a randomized response model based on the use of two decks of cards. In this paper, a modification to the structure of the two decks of cards used by Odumade and Singh (2009) is proposed. The condition when the proposed model is more efficient than the Odumade and Singh (2009) model has been obtained. The proposed model can be easily adjusted to be more efficient than the Warner (1965), Mangat and Singh (1990), Mangat (1994) and Odumade and Singh (2009) models. Another advantage of the proposed model is that it can increase the respondents’ cooperation as they will be required to answer the sensitive question only once and not twice as in the case of the Odumade and Singh (2009) model.

Thin-layer drying kinetics and quality changes of sweet sorghum stalk for ethanol production as affected by drying temperature

The chopped sweet sorghum stalk was thin-layer-dried for long-term storage and ethanol production. The drying kinetics and the effects of drying temperature on the qualities of sweet sorghum stalk were investigated in this work. The results showed that the drying process could be simulated well by Wang and Singh's model. The diffusivity constant ( D 0) and active energy ( E a ) were estimated as 4.4 × 10 −5 m 2/s and 21.4 kJ/(mol K) for drying the chopped fresh stalk. According to the sugar composition, browning degree, and fermentability of the dried stalk obtained at various temperatures, the approximate drying temperature could be suggested as 50–60 °C for application. In this range, the moisture of the chopped fresh stalk could drop below the safe moisture for storage in 7–5.5 h with 12.1–9.7% total sugar loss during the drying process.

Characteristics of thin‐layer drying and rehydration of nata de coco

SummaryNata is white gelatinous bacterial cellulose produced by Acetobacter aceti ssp. xylinum through fermentation of coconut water. Drying behaviour of nata de coco was conducted with a hot air dryer for a temperature range of 50–90 °C. The experimental data obtained were fitted into seven empirical and/or semi‐theoretical thin‐layer drying models using nonlinear regression analysis. Results showed that Logarithmic model, Wang and Singh model fitted better than Verma et al. model although all these three models were suitable for predicting the drying process of nata de coco. The rehydration capacity was lost severely when the moisture content of the samples was nearly zero, but it can almost rehydrate to its initial state when the moisture content was above 8%. The drying kinetic properties and rehydration capacity of nata de coco indicated that most of the moisture in nata de coco was free water.

MASS TRANSFER KINETICS OF BANANA SLICES DURING OSMO‐CONVECTIVE DRYING

ABSTRACT The mass transfer kinetics of banana slices during osmotic dehydration in terms of water loss and solid gain in sugar syrup was studied. The effect of process parameters such as thickness of banana slices (4, 8 and 12 mm), sugar syrup concentration (40, 50 and 60% w/w) and sample‐to‐sugar syrup solution ratio (1:2, 1:4 and 1:6) on water loss and solute gain were also evaluated. Water losses and solid gains were increased with increase in sugar syrup concentration and banana slice sample‐to‐sugar syrup solution ratio and it has increased with the decrease in thickness of banana slices. Two‐factor analysis of variance for all experiments indicated that osmosis time of banana and sugar syrup solution concentration, sample‐to‐sugar ratio and thickness of banana slices were highly significant, whereas combination osmosis time and sugar syrup solution concentration, sample‐to‐sugar ratio and thickness of banana slices were nonsignificant. Osmotic time of 5–6 h was required to attain maximum water loss and solid gain by banana slices. The optimum best combination of banana osmosis for water loss and solid gain were found to be: 50% sugar syrup solution + 8 mm thickness of banana slices + 1:6 sample‐to‐sugar syrup solution ratio. Drying kinetics of osmosis banana slices were studied in a laboratory model tray dryer at 55, 60 and 65C air temperature. Seven thin‐layer drying models were fitted to the experimental moisture ratio data. Among the mathematical models investigated, the Wang and Singh model satisfactorily described the drying behavior of banana with high r2 values of 0.9989. The effective moisture diffusivity ranged from 5.3 × 10−8to 9.3 × 10−8 m2/s.PRACTICAL APPLICATIONSThe process of osmotic dehydration can be used for the preparation of shelf‐stable products for the purpose of use during off‐season. The quality of pre‐osmosed banana slices are much more superior to the product dehydrated with the convectional method of convective dehydration. The osmotically dehydrated banana slices can be used as banana‐figs, fruit candy, fruit toffee, infant food and it can become part of foodstuffs like cakes, pastries and many others.

DRYING OF PARSLEY LEAVES IN A SOLAR DRYER AND UNDER OPEN SUN: MODELING, ENERGY AND EXERGY ASPECTS

ABSTRACT In this study, the thin layer drying characteristics in a solar dryer with forced convection and under open sun with natural convection of parsley was investigated, and energy analyses and exergy analyses of the solar drying process of parsley were performed. The drying data were fitted to the 10 different mathematical models. Among the models, the Wang and Singh model for the forced solar drying and the natural open sun drying were found to best explain thin layer‐drying behavior of parsley. Using the first law of thermodynamics, the energy analyses throughout the drying process were estimated. However, exergy analyses during the drying process were determined by applying the second law of thermodynamics. Energy utilization ratio (EUR) values of the drying cabinet varied in the ranges between 8.57–41.56%. The values of exergy inflow and exergy outflow were found to be in the range of 0.263–0.680 kJ/kg and 0.187–0.378 kJ/kg, respectively. The values of exergy loss and exergy efficiency were found to be in the range of 0.0347–0.399 kJ/kg and 35.76–86.79%, respectively. EUR decreased with increasing drying time while exergy efficiency increased. PRACTICAL APPLICATIONSDrying is widely used in a variety of thermal energy applications ranging from food drying to wood drying. Drying can either be done by traditional sun drying or industrially, through the use of solar dryers or hot‐air drying. The solar dryers could be an alternative to the hot‐air drying and open sun drying methods, especially in locations with good sunshine during the harvest season. This study is useful not only for producers of dry parsley, but also for all producers of dry herbs. It may be successfully used in the design, modeling, analysis and performance evaluation of solar and sun drying.

Drying kinetics and effective moisture diffusivity of bamboo shoot slices undergoing microwave drying

SummaryEffect of microwave power on moisture content, moisture ratio, drying rate, drying time and effective moisture diffusivity (Deff) of bamboo shoot was investigated using microwave drying. To study the effect of microwave power on drying, bamboo shoot samples (250 g) were dried at different power levels ranging from 140 to 350 W. To determine the kinetic parameters, drying data were fitted to various models based on the ratios of differences between initial and final moisture contents and equilibrium moisture content. Among the models proposed, Wang and Singh model gave a better fit for all drying conditions used. By increasing microwave output power, the Deff values increased from 4.153 × 10−10 to 22.835 × 10−10 m2 s−1. A third‐order polynomial relationship was found to correlate the Deff with moisture content. Further scope of this research work would include the effect of certain factors (shrinkage, case hardening, distortion of product and shape of bamboo shoot samples as an infinite slab) of practical significance to improve the model.

Effect of freezing temperature on rehydration and water vapor adsorption characteristics of freeze-dried rice porridge

Effect of freezing temperature of rice porridge on quality properties of freeze-dried rice porridge was investigated at various temperatures. Slow freezing produced porous freeze-dried rice porridges with large pores and more brittle structure than rapid freezing. All the quality properties tested were greatly influenced by both freezing temperature and temperature for the property evaluation. Both the initial rehydration ratio and the dissolution time of the freeze-dried rice porridge decreased with increase in water temperature. Results on the effect of freezing temperature on rehydration ratio and dissolution time indicated slow freezing is more preferable for the freeze-dried rice porridge. The Peleg model was fitted better than the Singh and Kulshrestha model to explain the water vapor adsorption kinetics. The activation energy for the water vapor adsorption of the freeze-dried rice porridge determined by using the Peleg model ranged 16.2–23.1 kJ/mol depending on the freezing temperature.

Drying of mint leaves in a solar dryer and under open sun: Modelling, performance analyses

In this study was investigated the thin-layer drying characteristics in solar dryer with forced convection and under open sun with natural convection of mint leaves, and, performed energy analysis and exergy analysis of solar drying process of mint leaves. An indirect forced convection solar dryer consisting of a solar air collector and drying cabinet was used in the experiments. The drying data were fitted to ten the different mathematical models. Among the models, Wang and Singh model for the forced solar drying and the natural sun drying were found to best explain thin-layer drying behaviour of mint leaves. Using the first law of thermodynamics, the energy analysis throughout solar drying process was estimated. However, exergy analysis during solar drying process was determined by applying the second law of thermodynamics. Energy utilization ratio (EUR) values of drying cabinet varied in the ranges between 7.826% and 46.285%. The values of exergetic efficiency were found to be in the range of 34.760–87.717%. The values of improvement potential varied between 0 and 0.017 kJ s −1. Energy utilization ratio and improvement potential decreased with increasing drying time and ambient temperature while exergetic efficiency increased.

Proposed Optimal Orthogonal New Additive Model (POONAM)

In this paper, the proposed optimal orthogonal new additive model (POONAM) is shown to remain more efficient than the recent additive model introduced by Gjestvang and Singh (2009). Several situations where the POONAM estimator shows efficiency over the Gjestvang and Singh (2009) model are simulated and investigated.