About

Ajay Shah is a Professor in the Department of Food, Agricultural and Biological Engineering at The Ohio State University. He holds a B.E. in Mechanical Engineering from the Institute of Engineering, Tribhuvan University in Nepal, an M.S. in Biological Engineering from Mississippi State University, and a Ph.D. in Agricultural and Biosystems Engineering from Iowa State University. His research focuses on engineering sustainable solutions for biomass production, including alternative natural rubber, energy, and feed crops. He works on harvest and post-harvest logistics, processing of diverse biomass, and the upcycling of organic wastes for added value. Additionally, his program aims to develop appropriate technologies for smallholder farmers in developing countries and to enhance the techno-economic and environmental impacts of biobased systems. He is associated with the BioSystems Analysis Lab and specializes in biomass feedstock logistics and bioenergy.

Research topics

• Engineering
• Chemistry
• Pulp and paper industry
• Agronomy
• Waste management
• Organic chemistry
• Environmental science
• Toxicology
• Botany
• Business
• Agricultural engineering
• Environmental engineering
• Ecology

Selected publications

• Endoplasmic Reticulum–Plasma Membrane Contacts as novel platforms for NADPH Oxidase 1 dependent superoxide production.

  Free Radical Biology and Medicine · 2026-05-01

  article
  PublisherDOI

• Integrating UAS Remote Sensing and Edge Detection for Accurate Coal Stockpile Volume Estimation

  Remote Sensing · 2025-09-10 · 1 citations

  articleOpen access

  Accurate stockpile volume estimation is essential for industries that manage bulk materials across various stages of production. Conventional ground-based methods such as walking wheels, total stations, Global Navigation Satellite Systems (GNSSs), and Terrestrial Laser Scanners (TLSs) have been widely used, but often involve significant safety risks, particularly when accessing hard-to-reach or hazardous areas. Unmanned Aerial Systems (UASs) provide a safer and more efficient alternative for surveying irregularly shaped stockpiles. This study evaluates UAS-based methods for estimating the volume of coal stockpiles at a storage facility near Cadiz, Ohio. Two sensor platforms were deployed: a Freefly Alta X quadcopter equipped with a Real-Time Kinematic (RTK) Light Detection and Ranging (LiDAR, active sensor) and a WingtraOne UAS with Post-Processed Kinematic (PPK) multispectral imaging (optical, passive sensor). Three approaches were compared: (1) LiDAR; (2) Structure-from-Motion (SfM) photogrammetry with a Digital Surface Model (DSM) and Digital Terrain Model (DTM) (SfM–DTM); and (3) an SfM-derived DSM combined with a kriging-interpolated DTM (SfM–intDTM). An automated boundary detection workflow was developed, integrating slope thresholding, Near-Infrared (NIR) spectral filtering, and Canny edge detection. Volume estimates from SfM–DTM and SfM–intDTM closely matched LiDAR-based reference estimates, with Root Mean Square Error (RMSE) values of 147.51 m3 and 146.18 m3, respectively. The SfM–intDTM approach achieved a Mean Absolute Percentage Error (MAPE) of ~2%, indicating strong agreement with LiDAR and improved accuracy compared to prior studies. A sensitivity analysis further highlighted the role of spatial resolution in volume estimation. While RMSE values remained consistent (141–162 m3) and the MAPE below 2.5% for resolutions between 0.06 m and 5 m, accuracy declined at coarser resolutions, with the MAPE rising to 11.76% at 10 m. This emphasizes the need to balance the resolution with the study objectives, geographic extent, and computational costs when selecting elevation data for volume estimation. Overall, UAS-based SfM photogrammetry combined with interpolated DTMs and automated boundary extraction offers a scalable, cost-effective, and accurate approach for stockpile volume estimation. The methodology is well-suited for both the high-precision monitoring of individual stockpiles and broader regional-scale assessments and can be readily adapted to other domains such as quarrying, agricultural storage, and forestry operations.

  PublisherOA PDFDOI

• Monitoring Historical Waste Coal Piles Using Image Classification and Change Detection Algorithms on Satellite Images

  Remote Sensing · 2025-09-01 · 1 citations

  articleOpen access

  Abandoned coal mine lands, particularly waste coal piles that predate the Surface Mining Control and Reclamation Act (SMCRA) of 1977, pose significant environmental and safety risks. Unlike sites mined after SMCRA—where operators are legally mandated to conduct reclamation—there is no legal obligation for companies or individuals to restore lands disturbed before the law’s enactment. As a result, these historical sites remain largely unmanaged and understudied. This study develops a satellite imagery-based analytical workflow to identify and monitor such historical waste coal piles. Using supervised classification of Sentinel-2 imagery with four machine learning models, we identified waste coal piles in both active mining areas and regions disturbed prior to SMCRA. Among the models tested, Random Forest achieved the highest accuracy for classifying waste coal, with a precision of 86% and a recall of 77%. A subsequent time-series analysis revealed that historical waste coal piles have undergone gradual but consistent vegetation recovery since 1986, indicating a natural reclamation process. These areas showed minimal changes in disturbance magnitude, suggesting the absence of significant disturbing events. In contrast, active mining regions showed substantial disturbance consistent with ongoing operations. The combined classification and change detection approach successfully distinguished historical waste coal piles from those in active mining regions, with a precision of 78% and recall of 100%. These findings highlight the potential of remote sensing and temporal analysis to support the identification and assessment of historical waste coal piles. The proposed approach can help prioritize reclamation efforts and inform policy decisions addressing the long-term environmental impacts of historical coal mining.

  PublisherOA PDFDOI

• Evaluation of Co-Pelletization of Corn Stover and Plastic Waste as an Alternative Fuel Source for Cement Production

  Energies · 2025-10-13

  articleOpen accessSenior authorCorresponding

  Corn stover and plastic waste, severely underutilized feedstocks generated in the U.S., could be co-pelletized to produce fuel for cement production. High-density polyethylene bags (0–25% in 5% increments, dry basis) and corn stover were co-pelletized using a flat ring pellet mill with die diameters of 6 and 8 mm. Physical and chemical properties were assessed to determine pellet quality. These results informed techno-economic and life cycle greenhouse gas emissions (GHGe) analyses for a Midwestern plant producing 400,000 metric tons of pellets annually. The system boundary included feedstock acquisition at the pellet plant, size reduction, co-pelletization, and transportation of the pellets to the cement plant by rail. Total resource requirements in terms of raw materials, labor, fuel, equipment, the facility, and utilities were estimated. It was determined that the pellets would be delivered to the cement plant at USD 112.4–138.6/t pellets. The life cycle analysis estimated a total GHGe of 1621.1–1753.1 kg CO2e/t pellets associated with the pellet production, transportation, and combustion. The results suggest that substituting 25% of the thermal energy requirement of a cement plant with a 1.1 million t clinker annual production capacity with plastic–stover pellets would reduce the GHGe by 2.8% compared to 100% of the total energy requirement supplied by coal.

  PublisherOA PDFDOI

• Determination of relative composition of samples collected with open head spiral grain sampling probe

  Journal of Stored Products Research · 2025-02-08

  articleOpen accessSenior authorCorresponding

  Grain sampling probes, also called spears and triers, are used to collect samples from bulk grain at rest and are known to draw a higher proportion from the uppermost levels. Probes are used to collect samples that will be aggregated for representative sampling but are also useful tools in grain drying research and in monitoring quality and pest presence during storage, where it is important to know how fully the sample represents the corresponding grain bed. In this study, a method was proposed to prepare color-differentiated 15.2 cm layers of corn to make a column of known proportions. A spiral open headed grain sample spear, which fills from the bottom to the top, was used to sample a column of 19.8% moisture dry basis dent corn, and the count and proportional mass of samples drawn with the spear were determined and correlated to the sample volume of a common handheld moisture meter tester (Agratronix MT-16 Grain Moisture Tester). Sampling methods of vertical grain spear insertion and USDA-recommended 10° from vertical were compared, and the impact of sampling higher-moisture corn kernels (24.8% dry basis) and a shorter 76 cm column was also determined. It was found that vertical sampling with the spiral spear had higher uniformity between samples, less top layer skew, and included more grain from the bottom layer compared to the 10° from vertical sampling angle. It was also found that the top skew was much higher with the shorter 76 cm column compared to the 91 cm column, and sampling of 24.8% grain did not have any statistically significant differences to samples collected of 19.8% grain. Finally, an adjustment factor is presented to find the weighted proportion of sampled grains reflective of 15.2 cm thin layers in a 91 cm column for 19.8% and 24.8% MC dent corn. • Color-differentiated layers of grain were sampled with a spiral probe. • Proportions and top-layer skew were determined for vertical and 10⁰ sampling. • Vertical sampling found to have higher repeatability and less top skew. • No difference in proportions across moisture levels evaluated. • Adjustment factors presented for aggregate and 90- mL subsamples.

  PublisherDOI

• Design and Feasibility Study of a Grid-Connected 30MW Large-Scale Solar Photovoltaic Plant

  Journal of Physics Conference Series · 2025-04-01 · 1 citations

  articleOpen access

  Abstract The integration of Large-Scale Solar (LSS) photovoltaic plants into Malaysia's power grid aims to lower dependency on conventional electricity generation sources, including coal and fossil fuels. The government intends to generate a total LSS capacity of 2.5 GW, providing 10% of the nation's electricity needs. Nonetheless, the complex configuration of the power grid often resulted in technical challenges during the integration of LSS, including power flow, system losses, and instability issues. Thus, the goal of this project is to design a 30 MW LSS power plant that complies with Malaysia's Grid Code Requirement. In phase 1, the optimal sizing of the photovoltaic system and inverter is calculated via SEDA's mathematical approach. In phase 2, the theoretical calculation is validated using PVSyst software, and in stage 3, load flow analysis is conducted in ETAP 19.0.1 software to evaluate the feasibility of integrating LSS into a 9-bus test system. The PVSyst simulation results indicated that the system could provide a 30 MW AC output utilizing all parameters derived from SEDA's mathematical approach. The feasibility analysis indicates that the test system, with an integrated LSS photovoltaic plant, functions within safe parameters under base conditions and complies with the Malaysian Grid Code.

  PublisherDOI

• Assessing the Multifaceted Tradeoffs of Agricultural Conservation Practices on Ecosystem Services in the Midwest U.S.

  Sustainability · 2024-06-30

  articleOpen access

  A comprehensive understanding of the potential effects of conservation practices on soil health, crop productivity, and greenhouse gas (GHG) emissions remains elusive, despite extensive research. Thus, the DeNitrification–DeComposition (DNDC) model was employed to evaluate the impact of eleven commonly practiced management scenarios on ecosystem services in the Western Lake Erie Basin, USA, from 1998–2020. Out of eleven scenarios, eight were focused on corn–soybean rotations with varied nitrogen application timing (50% before planting and 50% at either fall or spring during or after planting), or nitrogen source (dairy slurry or synthetic fertilizer (SF)), or tillage practices (conventional, no-till), or cereal rye (CR) in rotation. Remaining scenarios involved rotations with silage corn (SC), winter crops (CR or winter wheat), and alfalfa. The silage corn with winter crop and four years of alfalfa rotation demonstrated enhanced ecosystem services compared to equivalent scenario with three years of alfalfa. Applying half the total nitrogen to corn through SF during or after spring-planted corn increased yield and soil organic carbon (SOC) sequestration while raising global warming potential (GWP) than fall-applied nitrogen. The no-till practice offered environmental benefits with lower GWP and higher SOC sequestration, while resulting in lower yield than conventional tillage. The incorporation of CR into corn–soybean rotations enhanced carbon sequestration, increased GHG emissions, improved corn yield, and lowered soybean yield. Substituting SF with manure for corn production improved corn yield under conventional tillage and increased SOC while increasing GWP under both tillage conditions. While the role of conservation practices varies by site, this study’s findings aid in prioritizing practices by evaluating tradeoffs among a range of ecosystem services.

  PublisherOA PDFDOI

• Advances in Biorefinery of Cattle Manure for Value-Added Products

  Fermentation · 2024-11-07 · 8 citations

  articleOpen accessSenior authorCorresponding

  A large amount of cattle manure is generated in the US every year, creating challenges for ecosystem sustainability while offering opportunities for value-added products through biorefinery. While methods like land application, composting, and anaerobic digestion are well established for treating cattle manure, advanced biorefinery technologies are needed to enhance the utilization of cattle manure or its digestate. Based on the composition of cattle manure, this review discusses technologies for the biorefinery of cattle manure or its digestate, including the recovery of fiber and protein, and the production of platform chemicals, such as volatile fatty acids, lactic acid, medium-chain carboxylic acids, ethanol, single-cell protein, and lipids. Additionally, this review discusses process integration for simultaneously producing multiple value-added products from cattle manure using various biorefinery technologies. By offering insights into different approaches, this review aims to support the development of integrated biorefinery processes, thereby improving the economic and environmental sustainability of cattle manure management.

  PublisherOA PDFDOI

• Techno-economic analysis of electron beam irradiation pretreatment of corn straw for anaerobic digestion

  Sustainable Energy Technologies and Assessments · 2024-03-23 · 9 citations

  articleOpen accessSenior authorCorresponding

  The complexity of anaerobic digestion process and the risks of investing in new technologies are the main obstacles to improving anaerobic digestion technology. There is still a gap between research results and commercial applications. This study investigated the techno-economic feasibility and bottlenecks of introducing electron beam irradiation pretreatment technology into the commercial-scale anaerobic digestion plant. Model construction, parameter initialization and economic analysis were performed in SuperPro Designer software. The parameters used in the model were derived from experimental results, software built-in model and recent literature. The results show that the gross margin, return on investment, payback time, internal rate of return, and net present value of the system with electron beam irradiation pretreatment are 4.4 %, 9.8 %, 10.1 years, 8.0 % and $0.6 million, respectively. The corresponding values of the system without electron beam irradiation pretreatment are 9.9 %, 11.1 %, 8.9 years, 9.7 % and $1.5 million, respectively. The main factor affecting gross profit is tipping fee of liquid anaerobic digestion effluent, followed by plant size of anaerobic digestion, degradation efficiency of corn straw, and compost price. This study has guiding significance for the application of electron beam irradiation pretreatment technology in the production of renewable energy from lignocellulosic biomass.

  PublisherDOI

• Influence of Hydrothermal Carbonization (HTC) Temperature on Hydrochar and Process Liquid for Poultry, Swine, and Dairy Manure

  Environments · 2024-07-14 · 23 citations

  articleOpen access

  Hydrothermal carbonization (HTC) is a promising technology for wet manure treatment by converting animal manure into valuable fuels, materials, and chemicals. Among other HTC process parameters, the temperature influences HTC products the most. As various animal manures have different compositions, it is not certain how the HTC temperature influences the hydrochar and HTC process liquid. To evaluate the temperature’s effect on HTC, three different manures (poultry, swine, and dairy) were hydrothermally carbonized at three different temperatures (180, 220, and 260 °C), and solid and liquid products were characterized for their morphology, elemental compositions, and ions. The carbon contents of the hydrochar reached as high as 38.98 ± 0.36% and 40.05 ± 0.57% for poultry and swine manure, respectively, when these manures were treated at 260 °C. Ammonium showed an around 30% increase in poultry manure hydrochar with the increase in the HTC temperature. In contrast, in swine manure, it decreased by around 80%, and in dairy manure, the HTC temperature did not have any remarkable effect on the ammonium content. The process liquids from HTC of dairy manure at 220 °C showed the most balanced distribution of different ions, with 4970 ± 673 ppm of sodium, 4354 ± 437 ppm of ammonium, 2766 ± 417 ppm of potassium, 978 ± 82 ppm of magnesium, 953 ± 143 ppm of calcium, 3607 ± 16 ppm of chloride, and 39 ± 7 ppm of phosphate. These results emphasize the manure-specific effects of the HTC temperature on both solid and liquid products, indicating the need for optimized strategies to enhance HTC processes for various types of animal manures.

  PublisherOA PDFDOI

Frequent coauthors

• Nawa Raj Baral

  Lawrence Berkeley National Laboratory

  21 shared

• Ashish Manandhar

  The Ohio State University

  16 shared

• Matthew J. Darr

  11 shared

• Juliana Vasco‐Correa

  Pennsylvania State University

  10 shared

• Seyed Hashem Mousavi‐Avval

  Forest Products Laboratory

  8 shared

• Dorde Medic

  7 shared

• Sami Khanal

  The Ohio State University

  7 shared

• Luis Huezo

  North Carolina State University

  6 shared

Education

• Ph.D., Food, Agricultural and Biological Engineering

  The Ohio State University

  1999

• M.S., Food, Agricultural and Biological Engineering

  The Ohio State University

  1994

• B.S., Food, Agricultural and Biological Engineering

  The Ohio State University

  1992

Awards & honors

• NABEC Young Engineer of the Year Award