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Cost analysis model for catalytic conversion of syngas in to light hydrocarbon gases

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Information Processing in Agriculture 2015年第1期2卷 37-50页

作者： Yangyang Deng prem b.parajuli Hakkwan Kim Department of Agricultural and biological Engineering Mississippi State UniversityMississippi StateMS 39762United States

bio-gasification is a new technology and considered as a more efficient way to utilize *** economic feasibility becomes one of the greatest issues when we apply this new *** of economic feasibility of a bio-gasification facility needs better understanding of its production unit cost under different capacities and different working shift *** objective of this study was to evaluate the unit cost of biofuel products(Liquid HCs,Light HCs and Oxygenates CxHyOz)under different capacities using a modeling *** cost analysis model was developed using Visual basic Microsoft 2008,computer programming language and mathematical *** modeling results showed that the unit costs of biofuel product from bio-gasification facility were significantly affected by production capacities of *** the facility capacity increased from 65 to 10,000 N m^3 h^-1,the biofuel production unit cost of gas(Light HCs),oil(Liquid HCs),and aqueous(Oxygenates CxHyOz)decreased from$38.92 per MMbTU,$30.89 per gallon and$25.74 per gallon to$2.01 per MMbTU,$1.59 per gallon,and$1.33 per gallon,*** results of the sensitivity analysis showed that feedstock cost was the most sensitive cost factor on unit costs for all biofuel products at high *** cost analysis model developed in this study could be used to optimize production unit costs of bio-fuel products from bio-gasification facility.

关键词： biofuel bio-gasification Cost analysis model Production capacity Unit cost

Assessing model parameters sensitivity and uncertainty of streamflow,sediment,and nutrient transport using SWAT

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Information Processing in Agriculture 2019年第1期6卷 61-72页

作者： Abdullah O.Dakhlalla prem b.parajuli Department of Agricultural and biological Engineering Mississippi State UniversityMississippi StateMS 39762United States

The objectives of this study were to(1)simulate streamflow,total sediment(TS),total phosphorus(TP),and total nitrogen(TN)loads;and(2)use the sequential uncertainty fitting(SUFI-2)algorithm to quantify the model parameter sensitivity and uncertainty in simulating streamflow,TS,TP,and TN loads using Soil and Water Assessment(SWAT)model in big Sunflower River watershed(bSRW).The model was calibrated from 1996 to 2003 and validated from 2004 to 2010 for daily streamflow,TS load,TP load,and TN *** model performed well simulating daily streamflow(R^2=0.58-0.75,NSE=0.47-0.75),TS load(R^2=0.50-0.72,NSE=0.47-0.66),and TP load(R^2=0.79-0.82,NSE=0.73-0.77),and the model performance was slightly low for TN load(R^2=0.13-0.31,NSE=0.09 to 0.07).This study determined that parameter uncertainty was greatest for simulating TN load(p-factor=0.48,r-factor=1.25)and that parameter uncertainty was lowest for simulating streamflow(p-factor=0.70-0.78,r-factor=1.18-1.19).Output uncertainty was much greater during peak streamflow and peak pollutant loads compared to periods of low streamflow and low pollutant *** sensitivity analyses found that streamflow was most sensitive to Manning’s roughness coefficient for the main channel(CH_N2),TS load was most sensitive the peak rate adjustment factor for sediment routing in the tributary channels(ADJ_PKR),TP load was most sensitive to the Phosphorus enrichment ratio for loading with sediments(ERORGP),and TN load was most sensitive to the denitrification exponential rate coefficient(CDN).Uncertainty was found to be much greater during peak streamflow and peak pollutant loads compared to periods of low streamflow and low pollutant loads.

关键词： Model parameters Sensitivity Uncertainty SWAT Pollutant loads

Comparison of Potential bio-Energy Feedstock Production and Water Quality Impacts Using a Modeling Approach

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Journal of Water Resource and Protection 2012年第9期4卷 763-771页

作者： prem b. parajuli Mississippi State University

Cellulosic and agricultural bio-energy crops can be utilized as feedstock source for bio-fuels production and provide environmental benefits such as hydrology, water quality. This study compared potential feedstock yield and water quality benefit scenarios of six bio-energy crops: Miscanthus (Miscanthus-giganteus), Switchgrass (Panicum virgatum), Johnsongrass (Sorghum halepense), Alfalfa (Medicago sativa L.), Corn (Zea mays), and Soybean {Glycine max (L.) Merr.} at the watershed scale using Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated (1998 to 2002) and validated (2003 to 2010) using monthly measured USGS stream flow data. Model was further verified using available monthly sediment yield, and county level NASS corn and soybean yield data within the watershed. The long-term average annual potential feedstock yield as an alternative energy source was determined the greatest when growing Miscanthus grass scenario (21.9 Mg/ha) followed by Switchgrass (15.2 Mg/ha), Johnsongrass (12.1 Mg/ha), Alfalfa (7 Mg/ha), Corn (5.9 Mg/ha), and Soybean (2.35 Mg/ha). Model results determined the least amount of average annual sediment yield (1.1 Mg/ha) from the Miscanthus grass scenario and the greatest amount (12 Mg/ha) from the corn crop scenario. About 11% less annual average surface water flow from the watershed could be anticipated when converting land areas from soybean to Miscanthus grass. The results of this study suggested that growing Miscanthus grass in the UPRW would have the greatest potential feedstock yield and water quality benefits. The results of this study may help in developing future watershed management programs.

关键词： biofuels Feedstock Yield Stream Flow Water Quality SWAT Watershed

Sensitivity Analysis and Evaluation of Forest biomass Production Potential Using SWAT Model

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Journal of Sustainable bioenergy Systems 2014年第2期4卷 136-147页

作者： Sunita Khanal prem b. parajuli Department of Agricultural and biological Engineering Mississippi State University Mississippi State USA

Sensitivity analysis of crop parameters and the performance of SWAT (Soil and Water Assessment Tool) model to simulate potential forest biomass production were evaluated for the Upper Pearl River Watershed (UPRW). Local sensitivity analysis of seven crop parameters: radiation use efficiency (kg/ha)/(MJ/m2) (bIOE), potential maximum leaf area index for the plant (bLAI), fraction of growing season at which senescence becomes the dominant growth process (DLAI), fraction of the maximum plant leaf area index corresponding to the 1st point on the optimal leaf area development curve (LAIMX1), fraction of growing season corresponding to the 1st point on the optimal leaf area development curve (FRGRW1), plants potential maximum canopy height (m) (CHTMX), and maximum rooting depth for plant (mm) (RDMX) reveals that only three parameters: DLAI, bIOE and bLAI are sensitive to forest biomass production. Further, results indicate moderate sensitivity of DLAI and bIOE and low sensitivity of bLAI with relative sensitivity index of 0.44, 0.35 and 0.14, respectively. The performance of SWAT to simulate potential forest biomass was evaluated by comparing simulated data against three years of observed data that were obtained from USDA Forest Service website. The results indicate satisfactory performance of SWAT in predicting potential forest biomass, which is shown by the high value of coefficient of determination (R2 = 0.83), small root mean square error (RMSE = 11.11 Mg/ha), and small difference between mean. Results also reveal that the UPRW has the potential to produce approximately 49 Mg/ha of average forest biomass annually, which is approximately 6% less than the observed biomass.

关键词： Sensitivity Forest biomass SWAT Crop Parameter Watershed

Evaluating the Impacts of Forest Clear Cutting on Water and Sediment Yields Using SWAT in Mississippi

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Journal of Water Resource and Protection 2013年第4期5卷 474-483页

作者： Sunita Khanal prem b. parajuli Department of Agricultural and biological Engineering Mississippi State University Mississippi State USA

Forest clear cutting alters the hydrological processes such as interception, evapotranspiration and infiltration of the forested watershed and consequently increases the amount of water and sediment leaving the watershed. This study was conducted in the Upper Pearl River Watershed (UPRW) located in east-central Mississippito evaluate and compare the potential impacts of forest clear cutting on water and sediment yields using the Soil and Water Assessment Tool (SWAT) model. For this purpose, five hypothetical scenarios representing clear cutting at 10%, 20%, 30%, 55% and 75% of the total forest area of the watershed were generated. The SWAT model was first calibrated (1981-1995) and validated (1996-2008) for monthly stream flow, and later verified (February 2010 to December 2010) for monthly sediment load. Results show that the SWAT model was able to simulate stream flow and sediment load satisfactorily during the calibration/validation and verification periods, respectively. The potential changes caused in yields as a result of the changes in clearcut area were computed by comparing predicted yields from each clear cutting scenario and a base condition. Results from five scenarios demonstrate substantial increase in yields with an increase in the percentage of forest area clearcut. When compared with the base scenario, potential changes in water and sediment yields occur between 17% to 96% and 33% to 250%, respectively, with an increase in clearcut area from 10% to 75%. Results also indicate that, for all scenarios, percentage wise change is larger for sediment yield. Although predicted water and sediment yields generated from each scenario are subject to further verification with observed data, this study provides useful information about the potential amount of water and sediment yields that may be produced under each scenario, and that the potential changes that may happen on yields if similar magnitude of clear cutting occurs in the UPRW or in similar watershed.

关键词： Clear Cutting Hydrology Watershed Water Quality SWAT

Evaluation of Soil Organic Carbon and Soil Moisture Content from Agricultural Fields in Mississippi

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Open Journal of Soil Science 2013年第2期3卷 81-90页

作者： prem b. parajuli Sarah Duffy Department of Agricultural and biological Engineering Mississippi State University Starkville USA.

Independent observation of the effects of agricultural management practices on soil organic carbon (SOC) with soil moisture content (SMC) is essential to quantify their potential relationships for sustainable ecosystems. Soil water retention studies and soil carbon stocks have been mapped in some areas worldwide. However, few studies have been conducted in the southeastern US, particularly in Mississippi. The objectives of this research study were to collect soil samples from fields chosen to be representative of the watersheds they are contained within, analyze the soil samples for carbon content and soil moisture content, and evaluate the relationship between SOC and different parameters (land use, vertical distribution, temporal distribution, and soil moisture content). Field sites were chosen based on their compositional similarity shared with the watershed as a whole in the Town Creek watershed (TCW) and Upper Pearl River watershed (UPRW) in Mississippi. Monthly soil samples from different depths (6 inch, 12 inch, and 24 inch) were collected from crop, pasture, and forest field areas. Soil samples were analyzed using bench analysis, elemental analysis, and statistical analysis. This study was able to demonstrate the SOC distribution in the soil layers across all three land uses studied. It was also shown that there does seem to be an interactive effect of parameters such as land use type, vertical distribution, and time on carbon accretion within the soil. Results of this study also determined that the near surface (6-in) layer was found to contain significantly more carbon than either the 12 inch or 24 inch layers (p 0.01) across all field types. There was found to be a high degree of variability within the soil moisture data and correlation between SOC and SMC. It was found that carbon amount is not influenced by SMC but SMC could be influenced by SOC.

关键词： Soil Organic Carbon Soil Moisture Content Cropland Land Uses

Quantifying Hydrologic and Water Quality Responses to bioenergy Crops in Town Creek Watershed in Mississippi

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Journal of Sustainable bioenergy Systems 2013年第3期3卷 202-208页

作者： prem b. parajuli Sarah E. Duffy Department of Agricultural and biological Engineering Mississippi State University Starkville USA

bioenergy crops are considered as a feedstock source, which can be grown in marginal soils. However, these crops may have different levels of crop yield potential and environmental benefits. The objectives of this study were to model and compare the effects of four bioenergy crops (corn—Zea mays, soybean—Glycine max (L.) Merr., miscanthus—Miscanthus-giganteus, and switchgrass—Panicum virgatum) in the Town Creek watershed (TCW) in northeast Mississippi using the Soil and Water Assessment Tool (SWAT) model. The calibrated SWAT model for TCW was used to quantify impacts to streamflow, crop yield, and sediment yield. The SWAT model reasonably (ber, 2009) monthly streamflow (25.88 m3·s-1) from the TCW when compared with the USGS observed stream flow (29.34 m3·s-1. In addition, model reasonably predicted (±6%) average annual corn yield (4.66 Mg·ha-1) and soybean yield (1.42 Mg·ha-1) as compared to National Agricultural Statistics Service (NASS) reported average annual corn (4.96 Mg·ha-1) and soybean yield (1.34 Mg·ha-1) from the watershed. Further, the model simulated results from this study determined that long-term average annual feedstock yield from TCW is the greatest when growing miscanthus grass (817,732 Mg) followed by switchgrass (477,317 Mg), corn (236,132 Mg), and soybeans (65,235 Mg). The SWAT model predicted the greatest annual average sediment yield (6.62 Mg·ha-1) from continuous corn crop scenario while the perennial grasses (switchgrass and miscanthus) had the lowest sediment yield (2.91 Mg·ha-1 and 3.20 Mg·ha-1 respectively). Overall, producing a perennial grass in the TCW would provide the largest biomass feedstock source with the least environmental impact. The results of this study will help to

Threshold for initiation of motion of unimodal and bimodal sediments

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International Journal of Sediment Research 2013年第1期28卷 24-33页

作者： Shaileshkumar b.PATEL prem Lal PATEL Prakash Devidas POREY Water Resources Engineering CEDSardar Vallabhbhai National Institute of TechnologySurat-395007India Department of Civil Engineering Sardar Vallabhbhai National Institute of TechnologySurat-395007India Sardar Vallabhbhai National Institute of Technology Surat-395007India

Experimental data,obtained from previous studies,on Critical Tractive Stress(CTS) of non-uniform sediments, have been used to verify the adequacy of existing relationships for CTS of non-uniform bimodal *** in view the performance of such relationships,a new relationship for computation of dimensionless CTS of individual size fraction of non-uniform unimodal and bimodal sediments has been proposed in the form of power *** coefficient and exponent of the proposed power law have been empirically correlated with sediment characteristics for available sediment *** proposed relationship has been validated with independent flume and field data to assess their applicability for unimodal and bimodal sediments.

关键词： bimodal Critical tractive stress Non-uniform sediment Scaling size Unimodal

Unique and conserved features of floral evocation in legumes

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Journal of Integrative Plant biology 2014年第8期56卷 714-728页

作者： Lim Chee Liew Mohan b. Singh prem L. bhalla Plant Molecular biology and biotechnology Laboratory Melbourne School of Land and Environment University of Melbourne

Legumes, with their unique ability to fix atmo- spheric nitrogen, play a vital role in ensuring future food security and mitigating the effects of climate change because they use less fossil energy and produce less greenhouse gases compared with N-fertilized systems. Grain legumes are second only to cereal crops as a source of human and animal food, and they contribute approximately one third of the protein consumed by the human population. The productivityof seed crops, such as grain legumes, is dependent on flowering. Despite the genetic variation and importance of flowering in legume production, studies of the molecular pathways that control flowering in legumes are limited. Recent advances in genomics have revealed that legume flowering pathways are divergent from those of such model species as Arabidopsis thaliana. Here, we discuss the current understanding of flowering time regulation in legumes and highlight the unique and conserved features of floral evocation in legumes.

关键词： Flowering legume soybean