Bioresource and Agricultural Engineering Commons^™

Tissue Decellularization Methods, Christine E. Schmidt, Rebecca A. Wachs, Robert Chase Cornelison

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Provided herein are methods of producing an acellular tissue product wherein the method can include the step of inducing apoptosis and washing the tissue after induction of apoptosis with a tonic solution. Also provided herein are acellular tissue products produced by the methods provided herein and methods of administering the acellular tissue products to a subject in need thereof.

The Irreversible Momentum Of Clean Energy, Barack Obama

United States Department of Energy: Publications

The release of carbon dioxide (CO₂) and other greenhouse gases (GHGs) due to human activity is increasing global average surface air temperatures, disrupting weather patterns, and acidifying the ocean. Left unchecked, the continued growth of GHG emissions could cause global average temperatures to increase by another 4°C or more by 2100 and by 1.5 to 2 times as much in many midcontinent and far northern locations. Although our understanding of the impacts of climate change is increasingly and disturbingly clear, there is still debate about the proper course for U.S. policy—a debate that is very much on display …

2017 Nebraska Water Monitoring Programs Report, Marty Link, Ryan Chapman

Nebraska Department of Environmental Quality: Reports

The Nebraska Department of Environmental Quality (NDEQ) is charged with monitoring, assessing, and to the extent possible, managing the state’s water resources. The purpose of this work is to protect and maintain high quality water and encourage or execute activities to improve poor water quality. Monitoring is done on nearly 17,000 miles of flowing rivers and streams, more than 134,000 acres of surface water in lakes and reservoirs, as well as the vast storage of groundwater in Nebraska’s aquifers.

Correction: Messer, T.L.; Burchell, M.R.; Birgand, F. Comparison Of Four Nitrate Removal Kinetic Models In Two Distinct Wetland Restoration Mesocosm Systems. Water 2017, 9, 517, Tiffany L. Messer, Michael R. Burchell, François Birgand

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The authors wish to make the following corrections to this paper [1]:

(1): The author name “François Bírgand” should be François Birgand.

(2): Reference 38 should be the following:

Birgand, F.; Aveni-Deforge, K.; Smith, B.; Maxwell, B.M.; Horstman, M.; Gerling, A.B.; Carey, C.C. First report of a novel multiplexer pumping system coupled to a water quality probe to collect high temporal frequency in situ water chemistry measurements at multiple sites. Limnol. Oceanogr. Methods 2016, 14, 767–783, doi:10.1002/lom3.10122.

(3): Reference 49 should be the following:

Christensen, P.B.; Nielsen, L.P.; Sørensen, J.; Revsbech, N.P. Denitrification in Nitrate-Rich Streams: Diurnal and Seasonal Variation …

Comparison Of Four Nitrate Removal Kinetic Models In Two Distinct Wetland Restoration Mesocosm Systems, Tiffany L. Messer, Michael R. Burchell, François Birgand

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The objective of the study was to determine the kinetic model that best fit observed nitrate removal rates at the mesocosm scale in order to determine ideal loading rates for two future wetland restorations slated to receive pulse flow agricultural drainage water. Four nitrate removal models were investigated: zero order, first order decay, efficiency loss, and Monod. Wetland mesocosms were constructed using the primary soil type (in triplicate) at each of the future wetland restoration sites. Eighteen mesocosm experiments were conducted over two years across seasons. Simulated drainage water was loaded into wetlands as batches, with target nitrate-N levels typically …

Development And Validation Of A Tractor Drawbar Force Measurement And Data Acquisition System (Daq), James Roeber, Santosh Pitla, Roger M. Hoy, Joe D. Luck, Michael F. Kocher

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Matching agricultural tractors to implements towed by the drawbar is one of the important aspects of machinery management for ensuring optimum performance and fuel cost savings. A field deployable tractor draft force measurement and data acquisition system was developed and evaluated as part of this research project. A drawbar instrumented to measure draft force in field operating conditions was developed and statically calibrated. The drawbar was calibrated by applying loads from 4.45 to 134 kN using a hydraulic cylinder connected to a 444.8 kN load cell. Testing was conducted with the drawbar installed on a tractor on a concrete track. …

Green And Sustainable Technology For High-Efficiency And Low- Damage Manipulation Of Densely Crosslinked Proteins, Helan Xu, Kaili Song, Bingnan Mu, Yiqi Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A two-step technology using nontoxic and ecofriendly chemicals is developed for the durable setting of densely/highly crosslinked proteins, such as wool and hair. Currently, most technologies for morphological modification are effective only for materials from non-highly-crosslinked proteins and cellulose. Before their morphological change, only water is needed to interrupt hydrogen bonds and ionic linkages, which stabilize the relative positions of molecules in non-highlycrosslinked proteins and cellulose. However, highly crosslinked proteins contain disulfide crosslinks, which are insusceptible to water. Thus, the controlled cleavage of disulfide bonds is required for creating new morphologies of highly crosslinked protein materials, such as hair and …

Differences In Soil Biological Activity By Terrain Types At The Sub-Field Scale In Central Iowa Us, Amy L. Kaleita, Linda R. Schott, Sarah K. Hargreaves, Kirsten S. Hofmockel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soil microbial communities are structured by biogeochemical processes that occur at many different spatial scales, which makes soil sampling difficult. Because soil microbial communities are important in nutrient cycling and soil fertility, it is important to understand how microbial communities function within the heterogeneous soil landscape. In this study, a self-organizing map was used to determine whether landscape data can be used to characterize the distribution of microbial biomass and activity in order to provide an improved understanding of soil microbial community function. Points within a row crop field in southcentral Iowa were clustered via a self-organizing map using six …

The Assessment Of Water Resources In Ungauged Catchments In Rwanda, O. P. Abimbola, J. Wenninger, R. Venneker, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Study region: Rwanda is a landlocked country in Africa with precipitation ranging from 800 mm yr−1 in the east to 1500 mm yr−1 in high-altitude regions in the north and west. Study focus: Streamflow estimation is an important task that is required in water resource assessments due to its importance in planning, decision-making and economic development. In this study, streamflow characteristics of ungauged catchments in Rwanda were calculated using a regionalization approach based on climate similarity and stepwise multiple-regression analysis. One climatic homogeneous region was identified and datasets of nine gauged stations and general available catchment characteristics were …

A Geospatial Variable Rate Irrigation Control Scenario Evaluation Methodology Based On Mining Root Zone Available Water Capacity, K. A. Miller, Joe Luck, Derek M. Heeren, T. Lo, Derrel Martin, J. B. Barker

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Increasing concern for sustainable water use has the agriculture industry working toward higher efficiency in use of irrigation water. Recent advancements have improved the capabilities of center pivot irrigation systems to vary water application depths across the field, a technology known as variable rate irrigation (VRI). The goal of this study was to provide a geospatial method for potential VRI technology adopters to evaluate control scenarios and potential water savings using freely available datasets. Root zone available water capacity (R) was estimated spatially across two case study fields using the Natural Resources Conservation Service Gridded Soil Survey Geographic Database. The …

The Effect Of Single-Handed Lifting Tasks On The Activation Of The Neck-Shoulder Shared Musculature, Mohamed R. Amar, David Cochran, Jeffrey Woldstad

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The use of the hand in lifting has been linked to occupational injuries of the neck and shoulder. This research is aimed at examining the effect of work-related factors on the major neck-shoulder shared musculature activity on both sides of the cervical spine for a right-handed lifting task. Subjects lifted different weights from 20 different locations produced by the interaction of varying heights, reach distance, and angles simulating the work done by assembly line workers. All lifting tasks were done by the right hand. Bilateral electromyography data of major shared musculature (upper trapezius, sternocleidomastoid, and levator scapula) were collected using …

Regulation-Structured Dynamic Metabolic Model Provides A Potential Mechanism For Delayed Enzyme Response In Denitrification Process, Hyun-Seob Song, Dennis G. Thomas, James C. Stegen, Minjing Li, Chongxuan Liu, Xuehang Song, Xingyuan Chen, Jim K. Fredrickson, John M. Zachara, Timothy D. Scheibe

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In a recent study of denitrification dynamics in hyporheic zone sediments, we observed a significant time lag (up to several days) in enzymatic response to the changes in substrate concentration. To explore an underlying mechanism and understand the interactive dynamics between enzymes and nutrients, we developed a trait-based model that associates a community’s traits with functional enzymes, instead of typically used species guilds (or functional guilds). This enzyme-based formulation allows to collectively describe biogeochemical functions of microbial communities without directly parameterizing the dynamics of species guilds, therefore being scalable to complex communities. As a key component of modeling, we accounted …

Trend Analysis In Rainfall, Reference Evapotranspiration And Aridity Index In Southern Senegal: Adaptation To The Vulnerability Of Rainfed Rice Cultivation To Climate Change, Komlan Koudahe, Koffi Djaman, Ansoumana Bodian, Suat Irkmak, Mamadou Sall, Lamine Diop, Alpha B. Balde, Daran Rudnick

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rainfall and evapotranspiration are two vital elements for food production under rainfed agriculture. This study aims at investigating the combined changes in these variables in the form of aridly index in the southern Senegal. The temporal trends in annual and monthly (from May to October) aridity index, rainfall and evapotranspiration are examined and adaptation strategies to the vulnerability of rainfed rice cultivation to the changes are developed. The results show a significant decreasing trend in annual rainfall at all study locations for the period 1922-2015. When analyzing the trends in sub-periods, there are two clear patterns in the annual rainfall …

Performance Of Twelve Mass Transfer Based Reference Evapotranspiration Models Under Humid Climate, Koffi Djaman, Komlan Koudahe, Mamadou Sall, Isa Kabenge, Daran Rudnick, Suat Irkmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the …

Biofuels From Crop Residue: Soil Organic Carbon And Climate Impacts In The Us And India, Adam J. Liska

Adam Liska Papers

Soil organic carbon (SOC) levels are the balance of carbon inputs from plant material and loss from oxidation to CO₂ (SOC = I_C - kC_oc) SOC tends to decrease as atmospheric temperature increases.

In the US, SOC levels are highest in the north central region (Iowa) where maize & soybean are grown at high yields.

In the US, gross energy yield of biofuel production can be increased by using both maize grain & maize residue.

Are the US results relevant for India if crop residues are used for biofuels?

India’s estimated biomass production & potential in …

Runoff Water Quality Characteristics Following Swine Slurry Application Under Broadcast And Injected Conditions, Nicole R. Schuster, Shannon L. Bartelt-Hunt, Lisa M. Durso, John E. Gilley, Xu Li, David B. Marx, Amy M. Schmidt, Daniel D. Snow

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to measure the effects of swine slurry application method, time following slurry application, and runoff rate on selected water quality characteristics. Slurry from a commercial swine operation was broadcast or injected on field plots at a rate required to meet annual nitrogen requirements for corn. Rainfall simulation tests were conducted at five varying periods following slurry application. During each study period, three simulated rainfall events, separated by 24 h intervals, were applied for 30 min duration at an intensity of approximately 70 mm h^-1. Following the third rainfall simulation event, inflow was applied at …

Large Co2 And Ch4 Emissions From Polygonal Tundra During Spring Thaw In Northern Alaska, Naama Raz-Yaseef, Margaret S. Torn, Yuxin Wu, David P. Billesbach, Anna K. Liljedahl, Timothy J. Kneafsey, Vladimir E. Romanovsky, David R. Cook, Stan D. Wullschleger

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The few prethaw observations of tundra carbon fluxes suggest that there may be large spring releases, but little is known about the scale and underlying mechanisms of this phenomenon. To address these questions, we combined ecosystem eddy flux measurements from two towers near Barrow, Alaska, with mechanistic soil-core thawing experiment. During a 2 week period prior to snowmelt in 2014, large fluxes were measured, reducing net summer uptake of CO₂ by 46% and adding 6% to cumulative CH₄ emissions. Emission pulses were linked to unique rain-on-snow events enhancing soil cracking. Controlled laboratory experiment revealed that as surface ice …

Multiple Drivers Of Seasonal Change In Pri: Implications For Photosynthesis 1. Leaf Level, Anatoly A. Gitelson, John A. Gamon, Alexei E. Solovchenko

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this study was to explore the relationships between the photochemical reflectance index (PRI) at the leaf level and pigment pools, focusing on the constitutive role of pigments in influencing PRI over seasonal or ontogenetic time frames. The purpose was to re-evaluate the role of PRI as an indicator of seasonally shifting pigment (chlorophyll, carotenoid and anthocyanin) contents, and hence photosynthetic activity, across a range of tree and crop species. We studied natural vegetation — three tree species (maple, chestnut and beech) and two managed irrigated and rain-fed crop species (maize and soybean), contrasting in photosynthetic pathway and …

Multiple Drivers Of Seasonal Change In Pri: Implications For Photosynthesis 2. Stand Level, Anatoly A. Gitelson, John A. Gamon, Alexei E. Solovchenko

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this study was to explore the relationships between stand-level photochemical reflectance index (PRI) and canopy structure/ pigment pools, as well as light use efficiency (LUE) of photosynthetically active vegetation focusing on seasonal or ontogenetic time frames. PRI was originally designed as a means of assessing the xanthophyll cycle and LUE over short (e.g. diurnal) time frames, and few studies have explored the drivers of PRI over longer, seasonal time frames, particularly in crops having different photosynthetic pathways or canopy structures. Consequently, our purpose was to understand and quantify the drivers of PRI responses over seasonal time scales …

Soil Water Content Monitoring For Irrigation Management: A Geostatistical Analysis, J. Burdette Barker, Trenton E. Franz, Derek M. Heeren, Christopher M.U. Neale, Joe D. Luck

Department of Agricultural and Biological Systems Engineering: Faculty Publications

With the increasing attention to site-specific or variable rate irrigation management, it is helpful to reconsider the quantity and placement of soil water monitoring locations in this context. Volumetric soil water content (θ_v) was monitored using a neutron probe (NP) at 72 locations in a center pivot irrigated field in eastern Nebraska. Variance reduction and temporal stability analyses were performed on θ_v from shallow (∼top 46 cm) and full profile (∼122 cm) readings for four monitoring cycles in the 2015 growing season and 2016 preseason. Eleven additional cycles were included for a subset of the data for …