@article{solmon_chuang_meskhidze_chen_2009, title={Acidic processing of mineral dust iron by anthropogenic compounds over the north Pacific Ocean}, volume={114}, ISSN={["2169-8996"]}, DOI={10.1029/2008jd010417}, abstractNote={Atmospheric processing of mineral aerosol by anthropogenic pollutants may be an important process by which insoluble iron can be transformed into soluble forms and become available to oceanic biota. Observations of the soluble iron fraction in atmospheric aerosol exhibit large variability, which is poorly represented in models. In this study, we implemented a dust iron dissolution scheme in a global chemistry transport model (GEOS‐Chem). The model is applied over the North Pacific Ocean during April 2001, a period when concentrations of dust and pollution within the east Asia outflow were high. Simulated fields of many key chemical constituents compare reasonably well with available observations, although some discrepancies are identified and discussed. In our simulations, the production of soluble iron varies temporally and regionally depending on pollution‐to‐dust ratio, primarily due to strong buffering by calcite. Overall, we show that the chemical processing mechanism produces significant amounts of dissolved iron reaching and being deposited in remote regions of the Pacific basin, with some seasonal variability. Simulated enhancements in particulate soluble iron fraction range from 0.5% to 6%, which is consistent with the observations. According to our simulations, ∼30% to 70% of particulate soluble iron over the North Pacific Ocean basin can be attributed to atmospheric processing. On the basis of April 2001 monthly simulations, sensitivity tests suggest that doubling SO2 emissions can induce a significant increase (13% on average, up to 40% during specific events) in dissolved iron production and deposition to the remote Pacific. We roughly estimate that half of the primary productivity induced by iron deposition in a north Pacific high‐nutrient low‐chlorophyll region is due to soluble iron derived from anthropogenic chemical processing of Asian aerosol.}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES}, author={Solmon, F. and Chuang, P. Y. and Meskhidze, N. and Chen, Y.}, year={2009}, month={Jan} }
 @misc{chen_cheng_creamer_2008, title={Inhibition of anaerobic digestion process: A review}, volume={99}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2007.01.057}, abstractNote={Anaerobic digestion is an attractive waste treatment practice in which both pollution control and energy recovery can be achieved. Many agricultural and industrial wastes are ideal candidates for anaerobic digestion because they contain high levels of easily biodegradable materials. Problems such as low methane yield and process instability are often encountered in anaerobic digestion, preventing this technique from being widely applied. A wide variety of inhibitory substances are the primary cause of anaerobic digester upset or failure since they are present in substantial concentrations in wastes. Considerable research efforts have been made to identify the mechanism and the controlling factors of inhibition. This review provides a detailed summary of the research conducted on the inhibition of anaerobic processes. The inhibitors commonly present in anaerobic digesters include ammonia, sulfide, light metal ions, heavy metals, and organics. Due to the difference in anaerobic inocula, waste composition, and experimental methods and conditions, literature results on inhibition caused by specific toxicants vary widely. Co-digestion with other waste, adaptation of microorganisms to inhibitory substances, and incorporation of methods to remove or counteract toxicants before anaerobic digestion can significantly improve the waste treatment efficiency.}, number={10}, journal={BIORESOURCE TECHNOLOGY}, author={Chen, Ye and Cheng, Jay J. and Creamer, Kurt S.}, year={2008}, month={Jul}, pages={4044–4064} }
 @article{sharma-shivappa_chen_2008, title={conversion of cotton wastes to bioenergy and value-added products}, volume={51}, DOI={10.13031/2013.25377}, abstractNote={Cotton accounts for nearly 40% of global fiber production. While approximately 80 countries worldwide produce cotton, the U.S., China, and India together provide over half the world's cotton. High cotton production is accompanied by generation of tons of cotton waste each year. Large amounts of residue from the field and gins results in not only environmental problems due to disposal issues and cotton diseases and pests, but also difficulties in cultivation due to slow decomposition in the soil. Development of economical and efficient methods for utilizing and/or disposing of cotton waste have been investigated for years, but scale-up and marketing issues need to be resolved. Cotton waste can be used as an energy source through briquetting, pyrolysis, and anaerobic digestion. Studies suggest that composition of cotton waste is similar to other lignocellulosic feedstocks, and it has the potential to be used for bioethanol production. However, proper pretreatment strategies need to be developed to reduce lignin (comprising approximately 30%). Cotton waste can also be processed into industrial products such as animal feed and bedding, soil amendment, and substrate for vegetative growth through various treatments. Enzyme production through utilization of cotton waste as a carbon source is another potential application. A review of the various conversion processes suggests that although cotton waste is suitable for the production of a variety of products, in-depth investigation at the pilot scale is essential to determine process efficacy and economic feasibility.}, number={6}, journal={Transactions of the ASABE}, author={Sharma-Shivappa, R. R. and Chen, Y.}, year={2008}, pages={2239–2246} }
 @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<or=0.05) delignification (maximum of 29.51% for 2%, 30 min, 121 degrees C/15 psi) and cellulose conversion (49.8%) than sodium hydroxide pretreatment, but had a higher (p<or=0.05) cellulose conversion than sulfuric acid pretreatment. Ozone did not cause any significant changes in lignin, xylan, or glucan contents over time. Quadratic models using time, temperature, and concentration as continuous variables were developed to predict xylan and lignin reduction, respectively for sulfuric acid and sodium hydroxide pretreatments. In addition, a modified severity parameter (log M(0)) was constructed and explained most of the variation in xylan or lignin reduction through simple linear regressions.}, number={16}, journal={BIORESOURCE TECHNOLOGY}, author={Silverstein, Rebecca A. and Chen, Ye and Sharma-Shivappa, Ratna R. and Boyette, Michael D. and Osborne, Jason}, year={2007}, month={Nov}, pages={3000–3011} }
 @inproceedings{xu_chen_wang_sharma-shivappa_burns_cheng_2007, title={Alkaline pretreatment of switchgrass for bioconversion to ethanol}, booktitle={2007 ASABE Regional Annual Conference (Fletcher, North Carolina)}, author={Xu, J. and Chen, Y. and Wang, Z. and Sharma-Shivappa, R. R. and Burns, J. C. and Cheng, J. J.}, year={2007} }
 @article{chen_cheng_2007, title={Anaerobic waste treatment processes}, volume={79}, DOI={10.2175/106143007x218430}, abstractNote={Water Environment ResearchVolume 79, Issue 10 p. 1430-1450 Treatment SystemFree Access Anaerobic Waste Treatment Processes Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author First published: 01 October 2007 https://doi.org/10.2175/106143007X218430AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume79, Issue102007 Literature ReviewSeptember 2007Pages 1430-1450 RelatedInformation}, number={10}, journal={Water Environment Research}, author={Chen, Y. and Cheng, Jay}, year={2007}, pages={1430–1450} }
 @article{chen_cheng_2007, title={Effect of potassium inhibition on the thermophilic anaerobic digestion of swine waste}, volume={79}, ISSN={["1061-4303"]}, DOI={10.2175/106143007X156853}, abstractNote={The inhibition effects of high potassium concentration on thermophilic anaerobic digestion of swine waste were studied. A continuous stirred tank reactor (CSTR), operated at a hydraulic retention time of 10 days and chemical oxygen demand loading of 7.2 to 7.5 g/L/d, was used to digest swine waste and cultivate thermophilic anaerobic microorganisms. To evaluate the toxicity of potassium, batch inhibition tests were also conducted. Without acclimation to potassium, the inhibition threshold beyond which methane production decreased significantly was 3 g K +/L. Volatile fatty acids accumulation was observed during the decline of methane production. Propionic acid was the dominant fatty acid, indicating that propionic acid utilizers were more sensitive to potassium inhibition than acetoclastic methanogens. To test the effect of acclimation on potassium inhibition, the potassium concentration in the CSTR was increased to 6 and 9 g K +/L. Acclimation to 6 g K +/L increased the tolerance of anaerobic inocula to potassium inhibition without significantly reducing the methanogenic activity. The inhibition threshold was increased from 3 g K +/L for unacclimated inocula, to 6 g K +/L for inocula acclimated to 6 g/L of potassium. Acclimation of inocula to 9 g/L potassium further increased the inhibition threshold to 7.5 g K +/L. However, the overall methanogenic activity in the last case was lower than that of unacclimated and 6 g K +/L acclimated inocula.}, number={6}, journal={WATER ENVIRONMENT RESEARCH}, author={Chen, Ye and Cheng, Jay J.}, year={2007}, month={Jun}, pages={667–674} }
 @article{chen_sharma-shivappa_chen_2007, title={Ensiling agricultural residues for bioethanol production}, volume={143}, ISSN={["1559-0291"]}, DOI={10.1007/s12010-007-0030-7}, abstractNote={The potential of using ensiling, with and without supplemental enzymes, as a cost-effective pretreatment for bioethanol production from agricultural residues was investigated. Ensiling did not significantly affect the lignin content of barley straw, cotton stalk, and triticale hay ensiled without enzyme, but slightly increased the lignin content in triticale straw, wheat straw, and triticale hay ensiled with enzyme. The holocellulose (cellulose plus hemicellulose) losses in the feedstocks, as a result of ensiling, ranged from 1.31 to 9.93%. The percent holocellulose loss in hays during ensiling was lower than in straws and stalks. Ensiling of barley, triticale, wheat straws, and cotton stalk significantly increased the conversion of holocellulose to sugars during subsequent hydrolysis with two enzyme combinations. Enzymatic hydrolysis of ensiled and untreated feedstocks by Celluclast 1.5 L-Novozyme 188 enzyme combination resulted in equal or higher saccharification than with Spezyme CP-xylanase combination. Enzyme loadings of 40 and 60 FPU/g reducing sugars gave similar sugar yields. The percent saccharification with Celluclast 1.5 L-Novozyme 188 at 40 FPU/g reducing sugars was 17.1 to 43.6%, 22.4 to 46.9%, and 23.2 to 32.2% for untreated feedstocks, feedstocks ensiled with, and without enzymes, respectively. Fermentation of the hydrolysates from ensiled feedstocks resulted in ethanol yields ranging from 0.21 to 0.28 g/g reducing sugars.}, number={1}, journal={APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY}, author={Chen, Ye and Sharma-Shivappa, Ratna R. and Chen, Chengci}, year={2007}, month={Oct}, pages={80–92} }
 @article{chen_sharma-shivappa_keshwani_chen_2007, title={Potential of agricultural residues and hay for bioethanol production}, volume={142}, ISSN={["1559-0291"]}, DOI={10.1007/s12010-007-0026-3}, abstractNote={Production of bioethanol from agricultural residues and hays (wheat, barley, and triticale straws, and barley, triticale, pearl millet, and sweet sorghum hays) through a series of chemical pretreatment, enzymatic hydrolysis, and fermentation processes was investigated in this study. Composition analysis suggested that the agricultural straws and hays studied contained approximately 28.62-38.58% glucan, 11.19-20.78% xylan, and 22.01-27.57% lignin, making them good candidates for bioethanol production. Chemical pretreatment with sulfuric acid or sodium hydroxide at concentrations of 0.5, 1.0, and 2.0% indicated that concentration and treatment agent play a significant role during pretreatment. After 2.0% sulfuric acid pretreatment at 121 degrees C/15 psi for 60 min, 78.10-81.27% of the xylan in untreated feedstocks was solubilized, while 75.09-84.52% of the lignin was reduced after 2.0% sodium hydroxide pretreatment under similar conditions. Enzymatic hydrolysis of chemically pretreated (2.0% NaOH or H2SO4) solids with Celluclast 1.5 L-Novozym 188 (cellobiase) enzyme combination resulted in equal or higher glucan and xylan conversion than with Spezyme(R) CP- xylanase combination. The glucan and xylan conversions during hydrolysis with Celluclast 1.5 L-cellobiase at 40 FPU/g glucan were 78.09 to 100.36% and 74.03 to 84.89%, respectively. Increasing the enzyme loading from 40 to 60 FPU/g glucan did not significantly increase sugar yield. The ethanol yield after fermentation of the hydrolyzate from different feedstocks with Saccharomyces cerevisiae ranged from 0.27 to 0.34 g/g glucose or 52.00-65.82% of the theoretical maximum ethanol yield.}, number={3}, journal={APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY}, author={Chen, Ye and Sharma-Shivappa, Ratna R. and Keshwani, Deepak and Chen, Chengci}, year={2007}, month={Sep}, pages={276–290} }
 @article{chen_cheng_2006, title={Application of anaerobic processes}, volume={78}, DOI={10.2175/106143006X119224}, abstractNote={Anaerobic digestion includes a diverse array of biological waste treatment systems from which dissolved oxygen is excluded. Originally used to substantially destroy complex organic matter in wastes, anaerobic digestion technique has now found many new and evolving applications on pollution prevention, sustainable energy and nutrient recovery, as well as pathogen inactivation. The main objective of this article is to provide an overview of the recent research on the anaerobic digestion of agricultural, industrial, and municipal wastes. Information of the recent development in anaerobic microbiology and mathematical modeling is also covered in the article. 1 General}, number={10}, journal={Water Environment Research}, author={Chen, Y. and Cheng, Jay}, year={2006}, pages={1363–1385} }
 @misc{chen_cheng_2005, title={Anaerobic processes in waste treatment}, volume={77}, ISSN={["1554-7531"]}, DOI={10.2175/106143005X54407}, abstractNote={Anaerobic digestion is a biochemical conversion technology that can substantially destroy complex organic matter in wastes. When used in a fully engineered system, anaerobic digestion not only provides pollution prevention, but also allows for sustainable energy and nutrient recovery. As the technology continues to mature, anaerobic digestion is becoming a key method for both waste reduction and recovery of a renewable fuel and other valuable co-products. The main objective of this article is to provide an overview of the recent research on the anaerobic digestion of agricultural, industrial, and municipal wastes. Information of the recent development in anaerobic microbiology and mathematical modeling is also covered in the article.}, number={6}, journal={WATER ENVIRONMENT RESEARCH}, author={Chen, Ye and Cheng, Jay J.}, year={2005}, pages={1347–1388} }
 @misc{chen_cheng_2004, title={Anaerobic processes}, volume={76}, ISSN={["1554-7531"]}, DOI={10.2175/106143004X142040}, abstractNote={Water Environment ResearchVolume 76, Issue 6 p. 1155-1190 Treatment SystemFree Access Anaerobic Processes Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author Ye Chen, Ye ChenSearch for more papers by this authorJay J. Cheng, Jay J. ChengSearch for more papers by this author First published: 01 October 2004 https://doi.org/10.2175/106143004X142040AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume76, Issue62004 Literature ReviewSeptember-October 2004Pages 1155-1190 RelatedInformation}, number={6}, journal={WATER ENVIRONMENT RESEARCH}, author={Chen, Y and Cheng, JJ}, year={2004}, pages={1155–1190} }