@article{moore_jennings_monks_boyette_leon_jordan_ippolito_blankenship_chang_2023, title={Evaluation of electrical and mechanical Palmer amaranth (Amaranthus palmeri) management in cucumber, peanut, and sweetpotato}, volume={1}, ISSN={["1550-2740"]}, url={https://doi.org/10.1017/wet.2023.1}, DOI={10.1017/wet.2023.1}, abstractNote={Abstract}, journal={WEED TECHNOLOGY}, author={Moore, Levi D. D. and Jennings, Katherine M. M. and Monks, David W. W. and Boyette, Michael D. D. and Leon, Ramon G. G. and Jordan, David L. L. and Ippolito, Stephen J. J. and Blankenship, Colton D. D. and Chang, Patrick}, year={2023}, month={Jan} } @article{bartley iii_yap_jackson_fonteno_boyette_chaves-cordoba_2023, title={Quantifying the Sorptive Behavior of Traditional Horticultural Substrate Components Based on Initial Hydraulic Conditioning}, volume={58}, ISSN={["2327-9834"]}, DOI={10.21273/HORTSCI16698-22}, abstractNote={The ability of a substrate component (organic or inorganic) to capture and retain water (hydration and wettability) is important to investigate and promote water-use–efficient practices. Many factors may play a role in the wettability of the material, including the processing of the material and its initial handling. The goal of this experiment was to determine the effect of moisture content (MC) on the sorptive behavior of substrates after an initial and secondary hydration cycle. Coir, peat, and aged pine bark were evaluated at a 33%, 50%, and 66% MC by weight. At all moisture levels, coir and bark were minimally affected by MC or the initial hydration cycle. Peat was the most vulnerable to changes in sorptive behavior as a result of wetting and drying cycles. After a wetting and drying cycle, the maximum volumetric water content of peat from surface irrigation was reduced 21.5% (volumetrically), more than three times any other treatment. The hydration efficiency of peat was improved when blended with as little as 15% coir. These experiments provide evidence that MC and initial handling of the substrate can lead to differences in initial water use efficiency.}, number={1}, journal={HORTSCIENCE}, author={Bartley III, Paul C. and Yap, Ted C. and Jackson, Brian E. and Fonteno, William C. and Boyette, Michael D. and Chaves-Cordoba, Bernardo}, year={2023}, month={Jan}, pages={79–83} } @article{yu_shah_knauer_boyette_stikeleather_2021, title={Comprehensive Evaluation of a Landscape Fabric Based Solar Air Heater in a Pig Nursery}, volume={14}, ISSN={["1996-1073"]}, url={https://doi.org/10.3390/en14217258}, DOI={10.3390/en14217258}, abstractNote={Supplementing fossil fuels with solar air tempering for brooding young livestock could reduce energy use and improve indoor air quality. Metal transpired solar collectors (TSC) are effective but too expensive for heating livestock buildings. An inexpensive 12.7 m2 dark grey landscape-fabric-based transpired solar collector (fTSC) was evaluated in a swine nursery with two herds of pigs. A fraction of the fTSC area was underlain with phase change material (PCM) to store excess heat. The Test room with the fTSC was compared with an adjacent identical Control room, each with 120 piglets. The fTSC provided supplemental heating, e.g., with a suction velocity (Vs) of 0.027 m/s during a 9 h period, air temperature was increased by 11.6 °C (mean irradiance of 592 W/m2). Between 4 pm and 9 pm that same day, the PCM increased air temperature by 3.9 °C. The fTSC did not reduce propane use or improve pig performance. Higher Vs, operational changes and controller modifications could improve system performance and reduce cost. Modeling could be used to optimize PCM use. Hence, this very low-cost fabric-based solar air heater offers potential for considerable reduction in heat energy use in livestock barns.}, number={21}, journal={ENERGIES}, author={Yu, Li and Shah, Sanjay B. and Knauer, Mark T. and Boyette, Michael D. and Stikeleather, Larry F.}, year={2021}, month={Nov} } @article{haque_lobaton_nelson_yencho_pecota_mierop_kudenov_boyette_williams_2021, title={Computer vision approach to characterize size and shape phenotypes of horticultural crops using high-throughput imagery}, volume={182}, ISSN={0168-1699}, url={http://dx.doi.org/10.1016/j.compag.2021.106011}, DOI={10.1016/j.compag.2021.106011}, abstractNote={For many horticultural crops, variation in quality (e.g., shape and size) contributes significantly to the crop’s market value. Metrics characterizing less subjective harvest quantities (e.g., yield and total biomass) are routinely monitored. In contrast, metrics quantifying more subjective crop quality characteristics such as ideal size and shape remain difficult to characterize objectively at the production-scale due to the lack of modular technologies for high-throughput sensing and computation. Several horticultural crops are sent to packing facilities after having been harvested, where they are sorted into boxes and containers using high-throughput scanners. These scanners capture images of each fruit or vegetable being sorted and packed, but the images are typically used solely for sorting purposes and promptly discarded. With further analysis, these images could offer unparalleled insight on how crop quality metrics vary at the industrial production-scale and provide further insight into how these characteristics translate to overall market value. At present, methods for extracting and quantifying quality characteristics of crops using images generated by existing industrial infrastructure have not been developed. Furthermore, prior studies that investigated horticultural crop quality metrics, specifically of size and shape, used a limited number of samples, did not incorporate deformed or non-marketable samples, and did not use images captured from high-throughput systems. In this work, using sweetpotato (SP) as a use case, we introduce a computer vision algorithm for quantifying shape and size characteristics in a high-throughput manner. This approach generates 3D model of SPs from two 2D images captured by an industrial sorter 90 degrees apart and extracts 3D shape features in a few hundred milliseconds. We applied the 3D reconstruction and feature extraction method to thousands of image samples to demonstrate how variations in shape features across SP cultivars can be quantified. We created a SP shape dataset containing SP images, extracted shape features, and qualitative shape types (U.S. No. 1 or Cull). We used this dataset to develop a neural network-based shape classifier that was able to predict Cull vs. U.S. No. 1 SPs with 84.59% accuracy. In addition, using univariate Chi-squared tests and random forest, we identified the most important features for determining qualitative shape type (U.S. No. 1 or Cull) of the SPs. Our study serves as a key step towards enabling big data analytics for industrial SP agriculture. The methodological framework is readily transferable to other horticultural crops, particularly those that are sorted using commercial imaging equipment.}, journal={Computers and Electronics in Agriculture}, publisher={Elsevier BV}, author={Haque, Samiul and Lobaton, Edgar and Nelson, Natalie and Yencho, G. Craig and Pecota, Kenneth V. and Mierop, Russell and Kudenov, Michael W. and Boyette, Mike and Williams, Cranos M.}, year={2021}, month={Mar}, pages={106011} } @article{moore_jennings_monks_jordan_leon_boyette_2021, title={Evaluating shade cloth to simulate Palmer amaranth (Amaranthus palmeri) competition in sweetpotato}, volume={69}, ISSN={["1550-2759"]}, DOI={10.1017/wsc.2021.21}, abstractNote={Abstract}, number={4}, journal={WEED SCIENCE}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Jordan, David L. and Leon, Ramon G. and Boyette, Michael D.}, year={2021}, month={Jul}, pages={478–484} } @article{moore_jennings_monks_boyette_jordan_leon_2021, title={Herbicide systems including linuron for Palmer amaranth (Amaranthus palmeri) control in sweetpotato}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2020.63}, abstractNote={Abstract}, number={1}, journal={WEED TECHNOLOGY}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Boyette, Michael D. and Jordan, David L. and Leon, Ramon G.}, year={2021}, month={Feb}, pages={49–56} } @article{moore_jennings_monks_leon_boyette_jordan_2021, title={Influence of herbicides on germination and quality of Palmer amaranth (Amaranthus palmeri) seed}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2021.71}, abstractNote={Abstract}, number={5}, journal={WEED TECHNOLOGY}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Leon, Ramon G. and Boyette, Michael D. and Jordan, David L.}, year={2021}, month={Oct}, pages={786–789} } @article{kudenov_scarboro_altaqui_boyette_yencho_williams_2021, title={Internal defect scanning of sweetpotatoes using interactance spectroscopy}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0246872}, abstractNote={While standard visible-light imaging offers a fast and inexpensive means of quality analysis of horticultural products, it is generally limited to measuring superficial (surface) defects. Using light at longer (near-infrared) or shorter (X-ray) wavelengths enables the detection of superficial tissue bruising and density defects, respectively; however, it does not enable the optical absorption and scattering properties of sub-dermal tissue to be quantified. This paper applies visible and near-infrared interactance spectroscopy to detect internal necrosis in sweetpotatoes and develops a Zemax scattering simulation that models the measured optical signatures for both healthy and necrotic tissue. This study demonstrates that interactance spectroscopy can detect the unique near-infrared optical signatures of necrotic tissues in sweetpotatoes down to a depth of approximately 5±0.5 mm. We anticipate that light scattering measurement methods will represent a significant improvement over the current destructive analysis methods used to assay for internal defects in sweetpotatoes.}, number={2}, journal={PLOS ONE}, author={Kudenov, Michael W. and Scarboro, Clifton G. and Altaqui, Ali and Boyette, Mike and Yencho, G. Craig and Williams, Cranos M.}, year={2021}, month={Feb} } @article{moore_jennings_monks_leon_jordan_boyette_2021, title={Safety and efficacy of linuron with or without an adjuvant or S-metolachlor for POST control of Palmer amaranth (Amaranthus palmeri) in sweetpotato}, volume={35}, ISSN={["1550-2740"]}, DOI={10.1017/wet.2021.27}, abstractNote={Abstract}, number={3}, journal={WEED TECHNOLOGY}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Leon, Ramon G. and Jordan, David L. and Boyette, Michael D.}, year={2021}, month={Jun}, pages={471–475} } @article{moore_jennings_monks_jordan_boyette_leon_mahoney_everman_cahoon_2021, title={Susceptibility of Palmer amaranth accessions in North Carolina to atrazine, dicamba, S-metolachlor, and 2,4-D}, volume={11}, ISSN={["2374-3832"]}, url={https://doi.org/10.1002/cft2.20136}, DOI={10.1002/cft2.20136}, abstractNote={Core Ideas}, journal={CROP FORAGE & TURFGRASS MANAGEMENT}, publisher={Wiley}, author={Moore, Levi D. and Jennings, Katherine M. and Monks, David W. and Jordan, David L. and Boyette, Michael D. and Leon, Ramon G. and Mahoney, Dennis J. and Everman, Wesley J. and Cahoon, Charles W.}, year={2021}, month={Nov} } @article{baselga_schultheis_boyette_quesada-ocampo_starke_monks_2020, title={Vine Removal Prior to Harvest, and Curing Duration and Temperature Affect the Incidence and Severity of Internal Necrosis in 'Covington' Sweetpotato}, volume={30}, ISSN={["1943-7714"]}, DOI={10.21273/HORTTECH04408-19}, abstractNote={Internal necrosis (IN) is a physiological disorder that affects Covington, the most commonly grown sweetpotato (Ipomoea batatas) cultivar in North Carolina. Because IN affects the quality of sweetpotato storage roots, studies have been conducted since the first report of IN in 2006. Field studies (three in 2016 and two in 2017) were conducted to evaluate preharvest and postharvest treatments on the occurrence of IN in ‘Covington’ storage roots. Four preharvest treatments consisted of combinations of high chlorine or minimal chlorine potash fertilizer and mowing vs. not mowing before harvest. For postharvest treatments, 30 storage roots were obtained at harvest from each preharvest treatment plot and immediately cured in 75 and 85 °F rooms for a duration of 0.5, 1, 2, 3, and 5 weeks in 2016, and 0.5, 1, and 2 weeks in 2017. Shorter curing durations (0.5 and 1 week) coincided with industry recommendations while longer durations mimicked the challenges that some commercial facilities face when cooling down temperatures of rooms after curing is supposed to be concluded. Once curing temperature and curing duration treatments were completed, roots were placed in a 58 °F storage room at 85% relative humidity until cut. A control comparison was included in which harvested roots were placed in a 58 °F storage room (no curing) immediately after harvest. The storage roots from all temperature treatments were then cut 49 to 80 days after harvest, and incidence and severity of IN visually rated. Preharvest potash fertilizer treatments had minimal or no effect on occurrence of IN. However, mowing vines before harvest in several studies reduced IN incidence when roots were cured for more than 0.5 week at temperatures of at least 75 °F. Lower temperature (75 vs. 85 °F) and shorter curing duration (0.5 vs. 1, 2, 3, or 5 weeks) resulted in reduced IN occurrence in ‘Covington’ sweetpotato.}, number={5}, journal={HORTTECHNOLOGY}, author={Baselga, Fernando Montero de Espinosa and Schultheis, Jonathan R. and Boyette, Michael D. and Quesada-Ocampo, Lina M. and Starke, Keith D. and Monks, David W.}, year={2020}, month={Oct}, pages={544–551} } @article{johnson_bloom_dunning_gunter_boyette_creamer_2019, title={Farmer harvest decisions and vegetable loss in primary production}, volume={176}, ISSN={["1873-2267"]}, DOI={10.1016/j.agsy.2019.102672}, abstractNote={The topic of food loss and waste has risen in importance since the revelation that an estimated 40% of food in America is never consumed. Losses at the field level, however, are not well understood, and economic and growing conditions that dictate decisions made by fruit and vegetable growers can determine how much food is left unharvested. Many strategies have been suggested to reduce food loss and waste, but their development has been informed by concerns at the consumer level, and may not motivate growers to reduce losses. This study sought to understand how growers make decisions regarding when to end the harvest, and explores growers' perceptions of strategies that would incentivize them to reduce losses. The authors conducted seventeen semi-structured interviews with mid-sized to large commercial vegetable growers in North Carolina. The resulting findings clarify the primary decision-making drivers affecting food loss in the field, including whether growers have an interested buyer, the quality of the produce, the available price, the financial risk of product rejection, and the priority of another field becoming mature and ready to harvest. Growers did not perceive losses to be of high enough volume or value to measure crops that were left unharvested in the field, though research indicates that the volume is actually significant. We also asked growers about their perceptions of strategies for reducing farm level losses that have been promoted in industry reports on the subject. These strategies include facilitating donation and supporting emerging markets that focus on imperfect produce. Neither of these aligned well with strategies that growers perceived as important, such as increasing demand, providing processing infrastructure, and facilitating a consistent market and prices. While some growers donate produce or participate in gleaning, these activities can be limited by continued negative perceptions. Findings from this research suggest that, in order to effectively reduce the loss of edible food at the farm level, growers must be included in the development of strategies, and those strategies must incentivize their participation in order to be effective.}, journal={AGRICULTURAL SYSTEMS}, publisher={Elsevier BV}, author={Johnson, Lisa K. and Bloom, J. Dara and Dunning, Rebecca D. and Gunter, Chris C. and Boyette, Michael D. and Creamer, Nancy G.}, year={2019}, month={Nov} } @article{james_yuan_boyette_wang_2018, title={Airflow and insulation effects on simultaneous syngas and biochar production in a top-lit updraft biomass gasifier}, volume={117}, ISSN={["0960-1481"]}, DOI={10.1016/j.renene.2017.10.034}, abstractNote={The objective of this study was to understand the effect of airflow and insulation on syngas and biochar generations of rice hulls and woodchips in a top-lit updraft gasifier. Biochar yield decreased with increasing airflow. The highest biochar yields of 39% and 27% were achieved at 8 L/min airflow for rice hulls and woodchips, respectively. The mass fraction of syngas in the products increased with increasing airflow, which ranged from 88–89% for rice hulls and 93–94% for woodchips. The H2 composition in syngas also increased at higher airflow rates; it peaked at 4.2–4.4% for rice hulls and 5.7–6.6% (v/v) for woodchips, which was not affected by insulation. The carbon monoxide content in syngas ranged from approximately 12 to 15% (v/v) and was not affected by airflow or insulation. Average tar content in syngas decreased for both biomasses when airflow increased, but adding insulation resulted in significantly higher tar content in syngas. The biomass type also had significant effects on gasifier performance. Biochar yields from rice hulls were greater than that from woodchips at all airflow rates. The lowest tar contents in syngas were approximately 1.16 and 11.88 g/m3 for rice hulls and woodchips, respectively.}, journal={RENEWABLE ENERGY}, author={James, Arthur M. R. and Yuan, Wenqiao and Boyette, Michael D. and Wang, Donghai}, year={2018}, month={Mar}, pages={116–124} } @article{johnson_dunning_bloom_gunter_boyette_creamer_2018, title={Estimating on-farm food loss at the field level: A methodology and applied case study on a North Carolina farm}, volume={137}, ISSN={["1879-0658"]}, DOI={10.1016/j.resconrec.2018.05.017}, abstractNote={Current estimates of food loss at the farm level are either carried forward from decades-old estimates that rely on data from small farms using alternative agricultural practices, or they are based on grower estimates reported during interviews. A straightforward protocol adaptable to many crops is necessary to provide comparable data that can begin to fill gaps in knowledge on food loss in the US. Accurate estimation of on-farm losses for fruits and vegetables can inform ongoing national food loss and waste discussions and farm-level business decisions that hold potentially positive impacts for farm viability and resource-use efficiency. This paper describes a straightforward methodology for field-level measurement and demonstrates its utility on six vegetable crops harvested in 13 fields of a 121-hectare North Carolina vegetable farm. In this case, results showed that on average, approximately 65% of the unharvested crop that remained in the field was of wholesome, edible quality, although the appearance may not meet buyers' specifications for certain markets. The overall estimated average of vegetable crops that remained unharvested, yet were wholesome and available for recovery, was 8840 kg per hectare on the case study farm. The portion of the grower's reported total marketed yield that remained unutilized in the field averaged 57%, a figure greatly exceeding current estimates of farm level loss. Developing strategies to utilize these losses could enable growers to increase the amount of fresh produce moving into the supply chain, and represent a path towards sustainable intensification of vegetable crop production.}, journal={RESOURCES CONSERVATION AND RECYCLING}, publisher={Elsevier BV}, author={Johnson, Lisa K. and Dunning, Rebecca D. and Bloom, J. Dara and Gunter, Chris C. and Boyette, Michael D. and Creamer, Nancy G.}, year={2018}, month={Oct}, pages={243–250} } @article{poole_shah_grimes_boyette_stikeleather_2018, title={Evaluation of a novel, low-cost plastic solar air heater for turkey brooding}, volume={45}, ISSN={0973-0826}, url={http://dx.doi.org/10.1016/j.esd.2018.04.004}, DOI={10.1016/j.esd.2018.04.004}, abstractNote={Solar heat could displace fossil fuel to reduce energy cost for brooding livestock and poultry. A transpired solar collector (TSC), consisting of a perforated dark-colored metal surface, can provide considerable heating but metal TSCs (mTSCs) are expensive. Since a perforated black plastic sheet will be less-expensive, a plastic TSC (pTSC) was evaluated. The 1.49 m2 pTSC (porosity of 1.2%) supplemented a propane heater in a room housing 240 turkey poults; an adjacent room without a pTSC, with 240 poults was the control. Monitoring was performed over two flocks of poults. A custom-built controller bypassed the pTSC during nighttime or when the room did not require heating to bring in fresh air. The pTSC gave a maximum temperature rise of 25.4 °C at a solar irradiance (I) of 882 W/m2 and suction velocity (Vs) of 0.033 m/s over 15 min. Over 178 h of operation, with an average I of 668 ± 295 W/m2 and average Vs of 0.036 m/s, the pTSC increased air temperature by an average of 8.1 ± 4.2 °C. Probably due to higher ventilation rate and an oversized propane heater, propane use was not reduced in the Test room with the pTSC vs. the Control room. The Test room had lower CO2 and CO concentrations due to higher ventilation, which may have improved turkey performance. The metal TSC gave a slightly higher temperature rise at a lower Vs but the less-expensive pTSC could be a more cost-effective solar air heater that could readily be scaled up for agricultural and other applications in many parts of the world. Scale-up considerations seem feasible and are presented for a 10,000-poult brooder barn.}, journal={Energy for Sustainable Development}, publisher={Elsevier BV}, author={Poole, Mark R. and Shah, Sanjay B. and Grimes, Jesse L. and Boyette, Michael D. and Stikeleather, Larry F.}, year={2018}, month={Aug}, pages={1–10} } @article{poole_shah_boyette_grimes_stikeleather_2018, title={Evaluation of landscape fabric as a solar air heater}, volume={127}, ISSN={0960-1481}, url={http://dx.doi.org/10.1016/j.renene.2018.05.045}, DOI={10.1016/j.renene.2018.05.045}, abstractNote={Solar heating has great potential to displace fossil fuels in agricultural and industrial space heating. The conventional metal transpired solar collectors (mTSC) is highly-efficient but its high cost has impeded its adoption. While the plastic TSC (pTSC) would be less-expensive than the mTSC, it requires perforation. Since a high absorptance, non-woven landscape fabric is widely available and inexpensive, it could be cost-effective solar collector. The landscape fabric collector (fTSC) was compared with mTSC (anodized aluminum) and pTSC for temperature rise (ΔT) and efficiency (η) at two suction velocities (Vs). The mTSC and pTSC had porosity of 1.2% while the fTSC had a porosity of 80%. At 0.047 m/s, the fTSC produced higher average ΔT (by at least 2 °C) and average η (by at least 10%) than the mTSC and pTSC that were similar in performance. At the higher Vs of 0.060 m/s, the fTSC slightly outperformed the mTSC while the pTSC had the lowest ΔT and η. Superior performance of the fTSC was likely due to lower energy losses than the other two collectors as was indicated by its scanning electron microscope images. Modeling the fTSC as a simplified packed bed may be appropriate and challenges have been identified. Practical scale-up suggestions are provided. The fTSC is the least expensive solar air heater for space heating.}, journal={Renewable Energy}, publisher={Elsevier BV}, author={Poole, Mark R. and Shah, Sanjay B. and Boyette, Michael D. and Grimes, Jesse L. and Stikeleather, Larry F.}, year={2018}, month={Nov}, pages={998–1003} } @article{johnson_dunning_gunter_bloom_boyette_creamer_2018, title={Field measurement in vegetable crops indicates need for reevaluation of on-farm food loss estimates in North America}, volume={167}, ISSN={["1873-2267"]}, DOI={10.1016/j.agsy.2018.09.008}, abstractNote={Food loss and waste in the US has been estimated at 40%, a figure that does not include losses at the agricultural level. Consumer food waste is expensive and environmentally damaging as it travels the length of the supply chain and largely ends up in the landfill. Most research and campaigns emphasize the consumer level, which has resulted in the omission of data collection and development of solutions for producers of fruit and vegetable crops. The available estimates of edible produce lost in the field are based on assumptions and estimates, rather than field data. Therefore, this project aimed to measure losses in the field in order to understand if estimates are accurate. Sixty-eight fields of eight vegetable crops were evaluated on nine North Carolina farms during the 2017 production season, using a sampling and scaling method. Combining the unharvested crops of marketable quality and edible but not marketable quality (produce that does not meet appearance quality standards), the average produce volume available after the primary harvest was 5114.59 kg per hectare. Totaling an average of 42% of the marketed yield for these crops, these high figures indicate the need for a reevaluation of the food loss estimates at the agricultural level in the US, and a focus on solutions.}, journal={AGRICULTURAL SYSTEMS}, publisher={Elsevier BV}, author={Johnson, Lisa K. and Dunning, Rebecca D. and Gunter, Chris C. and Bloom, J. Dara and Boyette, Michael D. and Creamer, Nancy G.}, year={2018}, month={Nov}, pages={136–142} } @article{poole_shah_boyette_stikeleather_cleveland_2018, title={Performance of a coupled transpired solar collector—phase change material-based thermal energy storage system}, volume={161}, ISSN={0378-7788}, url={http://dx.doi.org/10.1016/j.enbuild.2017.12.027}, DOI={10.1016/j.enbuild.2017.12.027}, abstractNote={The transpired solar collector (TSC) is a low-cost technology for heating ventilation air for mainly for use in industrial and agricultural applications. Storing the excess energy generated during daytime in phase change material (PCM) could improve the economics of using TSCs. Since energy generated for storage could be increased by using a two-stage TSC (with a glazing) vs. a one-stage TSC, first, the thermal performance of the two configurations were compared. Then, performance of the PCM-based thermal energy storage (TES) unit coupled to a TSC was evaluated. At a suction velocity of 0.023 m/s, the one-stage TSC produced a 2 °C higher temperature rise and 8% higher efficiency than the two-stage TSC. The one-stage TSC was coupled to a TES unit packed with 80 kg of salt-hydrate type PCM (specific energy of ∼185 kJ/kg). When evaluated at four airflow rates, the TES unit stored between 76 and 107% of its theoretical heat storage capacity and provided tempered air 4 °C warmer than ambient air during nighttime. While residual energy (for daytime heating) increased with airflow rate, energy charged or discharged was unaffected. Over a week, the TSC-TEC stored 34% of the total useful energy produced for nighttime use, with a potential to displace 1.35 kg of liquefied natural gas. Replacing the expensive metal TSC with a perforated plastic TSC and a simpler TES design would improve the economics of storing solar energy for use after sundown.}, journal={Energy and Buildings}, publisher={Elsevier BV}, author={Poole, Mark R. and Shah, Sanjay B. and Boyette, Michael D. and Stikeleather, Larry F. and Cleveland, Tommy}, year={2018}, month={Feb}, pages={72–79} } @article{long_boyette_2017, title={Analysis of Micronized Charcoal for Use in a Liquid Fuel Slurry}, volume={10}, ISSN={["1996-1073"]}, DOI={10.3390/en10010025}, abstractNote={Yellow poplar ( Liriodendron tulipifera ) was chosen as the woody biomass for the production of charcoal for use in a liquid fuel slurry. Charcoal produced from this biomass resulted in a highly porous structure similar to the parent material. Micronized particles were produced from this charcoal using a multi-step milling process and verified using a scanning electron microscope and laser diffraction system. Charcoal particles greater than 50 µm exhibited long needle shapes much like the parent biomass while particles less than 50 µm were produced with aspect ratios closer to unity. Laser diffraction measurements indicated D10, D50, and D90 values of 4.446 µm, 15.83 µm, and 39.69 µm, respectively. Moisture content, ash content, absolute density, and energy content values were also measured for the charcoal particles produced. Calculated volumetric energy density values for the charcoal particles exceeded the No. 2 diesel fuel that would be displaced in a liquid fuel slurry.}, number={1}, journal={ENERGIES}, author={Long, John M. and Boyette, Michael D.}, year={2017}, month={Jan} } @article{james_yuan_boyette_wang_kumar_2016, title={Characterization of biochar from rice hulls and wood chips produced in a top-lit updraft biomass gasifier}, volume={59}, number={3}, journal={Transactions of the ASABE}, author={James, R. A. M. and Yuan, W. Q. and Boyette, M. D. and Wang, D. H. and Kumar, A.}, year={2016}, pages={749–756} } @article{james r._yuan_boyette_2016, title={The Effect of Biomass Physical Properties on Top-Lit Updraft Gasification ofWoodchips}, volume={9}, ISSN={["1996-1073"]}, DOI={10.3390/en9040283}, abstractNote={The performance of a top-lit updraft gasifier affected by biomass (pine wood) particle size, moisture content and compactness was studied in terms of the biochar yield, biomass burning rate, syngas composition and tar content. The highest biochar yield increase (from 12.2% to 21.8%) was achieved by varying the particle size from 7 to 30 mm, however, larger particles triggered tar generation that reached its maximum of 93.5 g/m 3 syngas at 30-mm biomass particles; in contrast, the hydrogen content in syngas was at its minimum of 2.89% at this condition. The increase in moisture content from 10% to 22% reduced biochar yield from 12% to 9.9%. It also reduced the tar content from 12.9 to 6.2 g/m 3 which was found to be the lowest range of tar content in this work. Similarly, the carbon monoxide composition in syngas decreased to its minimum of 11.16% at moisture content of 22%. Finally, the biomass compactness increased biochar yield up to 17% when the packing mass was 3 kg. However, the addition of compactness also increased the tar content in syngas, but little effect was noticed in syngas composition.}, number={4}, journal={ENERGIES}, author={James R., Arthur M. and Yuan, Wenqiao and Boyette, Michael D.}, year={2016}, month={Apr} } @article{judd_jackson_fonteno_evans_boyette_2015, title={Changes in Root Growth and Physical Properties in Substrates Containing Charred or Uncharred Wood Aggregates (c)}, volume={1085}, ISSN={["2406-6168"]}, DOI={10.17660/actahortic.2015.1085.86}, journal={PROCEEDINGS OF THE 2014 ANNUAL MEETING OF THE INTERNATIONAL PLANT PROPAGATORS SOCIETY}, author={Judd, Lesley A. and Jackson, Brian E. and Fonteno, William C. and Evans, Michael R. and Boyette, Michael D.}, year={2015}, pages={421–425} } @article{jiang_perkins-veazie_blankenship_boyette_pesic-vanesbroeck_jennings_schultheis_2015, title={Occurrence, severity and initiation of internal necrosis in 'Covington' sweetpotato}, volume={25}, number={3}, journal={HortTechnology}, author={Jiang, C. and Perkins-Veazie, P. and Blankenship, S. M. and Boyette, M. D. and Pesic-VanEsbroeck, Z. and Jennings, K. M. and Schultheis, J. R.}, year={2015}, pages={340–348} } @article{fitzgerald_kolar_classen_boyette_das_2015, title={Swine Manure Char as an Adsorbent for Mitigation of p-Cresol}, volume={34}, ISSN={["1944-7450"]}, DOI={10.1002/ep.11972}, abstractNote={There is a significant interest in synthesizing inexpensive adsorbents for mitigating pollutants emitted from animal agriculture industry such as p‐cresol. Biochar, a byproduct obtained from thermochemical biomass processing is one such source of adsorbent materials. However, presently there is not enough quantitative information on adsorption of p‐cresol on biochar. Hence, the goal of this research is to investigate swine manure char as an inexpensive adsorbent for removal of p‐cresol from an aqueous system. Swine manure was gasified for 15 min at 704°C to obtain gasified manure char. The char was characterized using physical and chemical techniques. Batch experiments were performed in duplicates at 25°C, 35°C, and 45°C to determine the adsorption isotherms and kinetics. Results indicated that gasification enhanced surface area and acid value of manure from 11.42 ± 0.20 to 49.12 ± 0.79 m2 g−1 and 7.81 ± 0.05 to 8.57 ± 0.01, respectively. The enhanced basicity of the resultant char promoted chemisorption of p‐cresol on char surface with maximum adsorption capacities of 7.63 mg g−1 (25°C), 14.99 mg g−1 (35°C), and 14.84 mg g−1 (45°C). Langmuir and Freundlich models suggested that adsorption of p‐cresol on char was favorable. Kinetic analysis of the data also confirmed chemisorption of p‐cresol while the analysis of transport processes suggested that internal diffusion of p‐cresol within the pores was the rate‐limiting step. Use of biochar as an adsorbent for p‐cresol will add value to gasification byproducts and simultaneously reduce water and air pollution associated with swine farming operations. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 125–131, 2015}, number={1}, journal={ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY}, author={Fitzgerald, Sterling and Kolar, Praveen and Classen, John and Boyette, Mike and Das, Lalitendu}, year={2015}, month={Jan}, pages={125–131} } @article{james_yuan_boyette_wang_2015, title={The Effect of Air Flow Rate and Biomass Type on the Performance of an Updraft Biomass Gasifier}, volume={10}, ISSN={["1930-2126"]}, DOI={10.15376/biores.10.2.3615-3624}, abstractNote={Airflow and the type of biomass are the two most important factors influencing the performance of a biomass gasifier. In this research, the effects of air flow rate (air-fuel equivalence ratios of 0.21, 0.25, and 0.29) and biomass type (woody biomass, agricultural residue, and perennial grass) on the performance of an updraft biomass gasifier were evaluated based on its tar and producer gas generation. It was found that increasing airflow increased the formation of tar species for all biomass types studied, but no significant differences in producer gas composition were found when the air-fuel equivalence ratio was changed. Thus, air-fuel equivalence ratios ranging from 0.21 to 0.25 were deemed appropriate for minimal tar generation. The results also showed that different biomass types generated producer gas with significantly different tar contents: woodchips yielded the most tar, followed by sorghum stover and prairie hay. The higher heating value of producer gas from various biomass types was also significantly different. Wood chip-derived producer gas had the greatest higher heating value, followed by prairie hay and sorghum stover. The carbon monoxide content in the produce gas of the three biomass types also exhibited significant differences with varying biomass type, similar to the higher heating value, but there were no significant differences in the H2 content with varying biomass type or airflow.}, number={2}, journal={BIORESOURCES}, author={James, Arthur M. and Yuan, Wenqiao and Boyette, Michael D. and Wang, Donghai}, year={2015}, pages={3615–3624} } @article{james_yuan_boyette_wang_kumar_2014, title={In-chamber thermocatalytic tar cracking and syngas reforming using char-supported NiO catalyst in an updraft biomass gasifier}, volume={7}, number={6}, journal={International Journal of Agricultural and Biological Engineering}, author={James, A. M. and Yuan, W. Q. and Boyette, M. D. and Wang, D. H. and Kumar, A.}, year={2014}, pages={91–97} } @article{smith_kolar_boyette_chinn_smith_gangadharan_zhang_2012, title={Advanced oxidation of toluene using Ni-olivine catalysts: part 2. Toluene oxidation kinetics and mechanism of Ni-olivine catalysts synthesized via electroless deposition and thermal impregnation}, volume={55}, DOI={10.13031/2013.42485}, abstractNote={The production of synthesis gas (syngas) involves the gasification of biomass under oxygen-limited conditions, which also produces tars. Tars pose significant problems for mechanical devices by depositing on piping, resulting in clogging and engine fouling. While recent research has shown that thermally impregnated Ni-olivine has been effective in reforming tars into H2 and CO, this technique possessed limited economic feasibility due to high input energy requirements. Thus, stable, active, and inexpensive catalysts are required for effective and efficient conditioning of syngas. This research compared the activity of Ni-olivine catalysts synthesized via electroless plating (ELP) (35°C) and thermal impregnation (TI) (1400°C) for oxiding toluene in a flow-through reactor. The objectives were to (1) determine the kinetics of toluene oxidation, (2) propose a reaction mechanism for toluene oxidation, and (3) investigate the effect of syngas on toluene oxidation. Conversion of toluene using Ni-olivine catalysts increased with increasing ozone concentration and temperature, as well as decreasing toluene molar flow rate, and facilitated the complete oxidation of toluene. The information obtained from this research is expected to provide opportunities for efficient cleanup of tars from biomass gasification facilities at lower temperatures.}, number={6}, journal={Transactions of the ASABE}, author={Smith, V. M. and Kolar, P. and Boyette, M. D. and Chinn, Mari and Smith, C. and Gangadharan, R. and Zhang, G.}, year={2012}, pages={2273–2283} } @article{boyette_2009, title={The investigation of negative horizontal ventilation for long-term storage of sweetpotatoes}, volume={25}, DOI={10.13031/2013.28843}, abstractNote={North Carolina is the largest producer of sweetpotatoes in the United States with an annual production of nearly 320 million kg (NCDACS, 2007). Under optimum storage conditions, sweetpotatoes may be held in marketable condition for longer than 10 months. This allows for orderly marketing throughout the year. In the last 15 years, several hundred long-term storage facilities have been built employing a novel air movement system now termed negative horizontal ventilation (NHV). Most of these facilities are located in North Carolina and other sweetpotato producing areas of the southeastern United States but some have been built in Asia, the Philippines, New Zealand, Canada, and Uruguay. This technology is especially suitable for the large commercial sweetpotato storage facilities now common in the industry. Pack-out percentages (defined as the salable weight removed from storage compared to the salable weight entering) for 8 to 10 month storage utilizing the NHV system average 90%. This compares to 60% to 70% for previous common storage methods and facilities. This article summarizes some of the efforts towards design optimization of these facilities for the curing and storing of sweetpotatoes}, number={5}, journal={Applied Engineering in Agriculture}, author={Boyette, M. D.}, year={2009}, pages={701–708} } @article{silverstein_chen_sharma-shivappa_boyette_osborne_2007, title={A comparison of chemical pretreatment methods for improving saccharification of cotton stalks}, volume={98}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2006.10.022}, abstractNote={The effectiveness of sulfuric acid (H(2)SO(4)), sodium hydroxide (NaOH), hydrogen peroxide (H(2)O(2)), and ozone pretreatments for conversion of cotton stalks to ethanol was investigated. Ground cotton stalks at a solid loading of 10% (w/v) were pretreated with H(2)SO(4), NaOH, and H(2)O(2) at concentrations of 0.5%, 1%, and 2% (w/v). Treatment temperatures of 90 degrees C and 121 degrees C at 15 psi were investigated for residence times of 30, 60, and 90 min. Ozone pretreatment was performed at 4 degrees C with constant sparging of stalks in water. Solids from H(2)SO(4), NaOH, and H(2)O(2) pretreatments (at 2%, 60 min, 121 degrees C/15 psi) showed significant lignin degradation and/or high sugar availability and hence were hydrolyzed by Celluclast 1.5L and Novozym 188 at 50 degrees C. Sulfuric acid pretreatment resulted in the highest xylan reduction (95.23% for 2% acid, 90 min, 121 degrees C/15 psi) but the lowest cellulose to glucose conversion during hydrolysis (23.85%). Sodium hydroxide pretreatment resulted in the highest level of delignification (65.63% for 2% NaOH, 90 min, 121 degrees C/15 psi) and cellulose conversion (60.8%). Hydrogen peroxide pretreatment resulted in significantly lower (p