Engineering Commons^™

Usability Assessment Of Two Different Control Modes For The Master Console Of A Laparoscopic Surgical Robot, Xiaoli Zhang, Carl A. Nelson, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this study is to evaluate potential interface control modes for a compact fourdegree- of-freedom (4-DOF) surgical robot. The goal is to improve robot usability by incorporating a sophisticated haptics-capable interface. Two control modes were developed using a commercially available haptic joystick: (1) a virtually point-constrained interface providing an analog for constrained laparoscopic motion (3-DOF rotation and 1-DOF translation), and (2) an unconstrained Cartesian input interface mapping more directly to the surgical tool tip motions. Subjects (n = 5) successfully performed tissue identification and manipulation tasks in an animal model in point-constrained and unconstrained control modes, respectively, with …

Tool Sequence Trends In Minimally Invasive Surgery: Statistical Analysis And Implications For Predictive Control Of Multifunction Instruments, Carl A. Nelson, Evan Luxon, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents an analysis of 67 minimally invasive surgical procedures covering 11 different procedure types to determine patterns of tool use. A new graph-theoretic approach was taken to organize and analyze the data. Through grouping surgeries by type, trends of common tool changes were identified. Using the concept of signal/noise ratio, these trends were found to be statistically strong. The tool-use trends were used to generate tool placement patterns for modular (multi-tool, cartridge-type) surgical tool systems, and the same 67 surgeries were numerically simulated to determine the optimality of these tool arrangements. The results indicate that aggregated tool-use data …

The Impact Of Wire Stent Fabrication Technique On The Performance Of Stent Placement, Shijia Zhao, Xiangyi (Cheryl) Liu, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Braided wire stents demonstrate distinct characteristics compared to welded ones. In this study, both braided and welded wire stents with the same nominal dimensions were crimped inside a sheath and then deployed into a stenosed artery using finite element analysis. The braided wire stent was generated by overlapping wires to form crisscross shape. A welded wire stent was created by welding the intersection points of wires to avoid sliding between wires. The effect of fabrication technique on mechanical behavior of Nitinol wire stents was evaluated. The results showed that relative sliding between wires reduced the deformation of the braided stent, …

Arterial Wall Mechanics And Clinical Implications After Coronary Stenting: Comparisons Of Three Stent Designs, Linxia Gu, Shijia Zhao, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this work is to quantitatively assess the relationship between the reported restenosis rates and stent induced arterial stress or strain parameters through finite element method. The impact of three stent designs (Palmaz–Schatz stent, Express stent, and Multilink Vision stent) on the arterial stress distributions were characterized. The influences of initial stent deployment location, stent-tissue friction, and plaque properties on the arterial stresses were also investigated. Higher arterial stresses were observed at the proximal end of the plaque. The Multilink–Vision stent induced lesser stress concentrations due to the high stiffness of the Cobalt Chromium material and thinner strut …

In Vivo Demonstration Of Surgical Task Assistance Using Miniature Robots, Jeff A. Hawks, Jacob Kunowski, Stephen R. Platt

Department of Mechanical and Materials Engineering: Faculty Publications

Laparoscopy is beneficial to patients as measured by less painful recovery and an earlier return to functional health compared to conventional open surgery.However, laparoscopy requires the manipulation of long, slender tools from outside the patient’s body. As a result, laparoscopy generally benefits only patients undergoing relatively simple procedures. An innovative approach to laparoscopy uses miniature in vivo robots that fit entirely inside the abdominal cavity. Our previous work demonstrated that a mobile, wireless robot platform can be successfully operated inside the abdominal cavity with different payloads (biopsy, camera, and physiological sensors). We hope that these robots are a step toward …

Analysis Of A Monolithic, Two-Dimensional Array Of Quartz Crystal Microbalances Loaded By Mass Layers With Nonuniform Thickness, Nan Liu, J. S. Yang, Ji Wang

Department of Mechanical and Materials Engineering: Faculty Publications

We study free thickness-shear vibrations of a monolithic, two-dimensional, and periodic array of quartz crystal microbalances loaded by mass layers with gradually varying thickness. A theoretical analysis is performed using Mindlin’s two-dimensional plate equation. It is shown that the problem is mathematically governed by Mathieu’s equation with a spatially varying coefficient. A periodic solution for resonant frequencies and modes is obtained and used to examine the effects of the mass layers. Results show that the vibration may be trapped or untrapped under the mass layers. The trapped modes decay differently in the two in-plane directions of the plate. The mode …

An Investigation Of Reflective Mulches For Use Over Capillary Mat Systems For Winter-Time Greenhouse Strawberry Production, George E. Meyer, Ellen T. Paparozzi, Elizabeth Walter-Shea, Erin E. Blankenship, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

Photosynthethically active radiation (PAR) is a principle environmental variable used by horticultural specialists, agronomists and ecosystem modelers to characterize the quantity and quality of light conducive to plant growth and development. Spatial distribution of PAR in a greenhouse can be quite variable and diffuse throughout the day time photoperiod, especially at low sun angles in northern regions of the United States. Four colors of reflective plastic mulches (white, red, olive, and black) were evaluated for winter-time strawberry (Fragaria × ananassa Duch.) production based on their reflectance and transmittance properties in a double-polyethylene, plastic-glazed Quonset greenhouse inNebraska. The spectral properties …

Development Of Tailor-Designed Gold-Platinum Nanoparticles Binary Catalysts For Efficient Formic Acid Electrooxidation, Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof, Mohamed S. El-Deab Prof, Bahgat E. El-Anadouli Prof

Chemical Engineering

The modification of a glassy carbon (GC) electrode with platinum (PtNPs) and gold (AuNPs) nanoparticles is targeted to fabricate efficient anodes for the electrooxidation of formic acid (FA). A proper adjustment of the deposition sequence of PtNPs and AuNPs could eventually enhance the electrocatalytic activity of the electrode in such a way that suppresses the CO poisoning effect during FA oxidation. The highest catalytic activity is obtained at the Au/Pt/GC electrode (with PtNPs firstly deposited on the GC electrode followed by AuNPs). This superb enhancement is quantified by comparing the relative ratio of the direct vs. the indirect oxidation peaks …

A 3-D Computational Fluid Dynamics Model For Forced Air Cooling Of Eggs Placed In Trays, Vikas Kumar, Ai Pheeng Wee, Sohan Birla, Jeyamkondan Subbiah, Harshanardhan Thippareddi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Shell eggs must be cooled quickly after laying for controlling Salmonella Enteritidis (SE) growth. To fulfill a research need identified by Food Safety and Inspection Service (FSIS), a 3-D Computational Fluid Dynamics (CFD) model was developed to predict the temperature of eggs placed on a tray (6 rows × 5 columns) under forced air cooling. The continuity, momentum, and energy equations were solved along with standard k-ε turbulence model using PHOENICS software. The model was validated by conducting experiments in a wind tunnel at various air temperatures (7–11 °C) and velocities (0.3– 0.7 m/s). Root mean square error for predicting …

The Biological Systems Engineering Program In Nebraska 1895-2011, William Splinter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

4. Preface: How Mechanization Has Impacted Food Production THE PIONEERS WHO ESTABLISHED THIS DEPARTMENT 8 Oscar Van Pelt Stout 10 Charles Russ Richards 12 J. Brownlee Davidson 14 Leon W. Chase FORMER FACULTY AND THEIR CONTRIBUTIONS 18 Laurence Froyd Seaton 20 Ivan D.Wood 22 Oscar W. Sjogren 23 Chauncey W. Smith 25 Elmer E. Brackett 27 Claud Kedzie Shedd 29 Ruby M. Loper 31 Lester F. Larsen 33 Lloyd W. Hurlbut 36 Rollin Schnieder 39 Howard D. Wittmuss 41 Deon Axthelm 46 Paul. E. Fischbach 48 Stuart O. Nelson 51 Kenneth von Bargen 56 John R. Davis 58 Robert W. …

Evaluation Of The Impact Of Surface Residue Cover On Single And Dual Crop Coefficient For Estimating Soybean Actual Evapotranspiration, Lameck O. Odhiambo, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Single and dual crop coefficient methods are used in conjunction with grass reference evapotranspiration (ET_o) to estimate actual crop evapotranspiration (ET_c). However, the impact of soil surface residue cover on the accuracy of ET_c estimated with these methods is not well understood. The objective of this study is to evaluate and compare the accuracy of the FAO-56 single crop coefficient (single-K_c) and dual crop coefficient (dual-K_c) methods for estimating soybean [Glycine max (L.) Merr.] ET_c in a partially residue covered field. The study was conducted …

Using Rapid Geomorphic Assessments To Assess Streambank Stability In Oklahoma Ozark Streams, Derek M. Heeren, Aaron R. Mittelstet, Garey A. Fox, Daniel E. Storm, Abdulsahib T. Al-Madhhachi, Taber L. Midgley, Ashley F. Stringer, Kevin B. Stunkel, Ron D. Tejral

Department of Agricultural and Biological Systems Engineering: Faculty Publications

High streambank erosion and failure rates on streams in the Ozark ecoregion of Oklahoma may be attributed to land use change and degradation of riparian areas. Numerous benefits may be achieved from streambank stabilization, but methods are needed to determine the most critical reaches for investing limited funds. Rapid geomorphic assessments (RGAs) have been used to aid in prioritizing stream reaches. This research (1) applied an existing RGA, the channel stability index (CSI), on several reaches along the Barren Fork Creek and Spavinaw Creek, and (2) modified the existing RGA to create an ecoregion-specific RGA called the Oklahoma Ozark streambank …

Climate Change Impacts On Streamflow, Water Quality, And Best Management Practices For The Shell And Logan Creek Watersheds In Nebraska, M. W. Van Liew, S. Feng, T. B. Pathak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Improvements in the management of water, sediment, and nutrients under future climatic conditions are needed to ensure increased crop and livestock production to meet greater global needs and the future availability of water for competing demands and protection against adverse water quality impairments. This study determined the impacts of future climate change scenarios on streamflow, water quality, and best management practices (BMPs) for two watersheds in Nebraska, USA. The Soil and Water Assessment Tool (SWAT) was employed to simulate streamflow, sediment, total nitrogen (N) and total phosphorus (P) from the Shell Creek Watershed near Columbus, Nebraska and the Logan Creek …

Carbon, Water, And Heat Flux Responses To Experimental Burning And Drought In A Tallgrass Prairie, Marc L. Fischer, M S. Torn, David P. Billesbach, Geoffrey Doyle, Brian Northup, Sebastien C. Biraud

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Drought and fire are common disturbances to grassland ecosystems. We report two years of eddy covariance ecosystem–atmosphere fluxes and biometric variables measured in nearby burned and unburned pastures in the US Southern Great Plains. Over the course of the experiment, annual precipitation (∼600 mm yr⁻¹) was lower than the long term mean (∼860 mm yr⁻¹). Soil moisture decreased from productive conditions in March 2005 dry, unproductive conditions during the growing season starting in March 2006. Just prior to the burn in early March 2005, burned and unburned pastures contained 520 ± 60 and 360 ± 40 …

Global Estimation Of Evapotranspiration Using A Leaf Area Index-Based Surface Energy And Water Balance Model, H. Yan, S.Q. Wang, David P. Billesbach, Walter Oechel, J.H. Zhang, Tilden Meyers, Ta. Martin, Roser Matamala, Dennis D. Baldocchi, G. Bohrer, D. Dragoni, R. Scott

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Studies of global hydrologic cycles, carbon cycles and climate change are greatly facilitated when global estimates of evapotranspiration (E) are available. We have developed an air-relative-humidity-based two-source (ARTS) E model that simulates the surface energy balance, soil water balance, and environmental constraints on E. It uses remotely sensed leaf area index (L_ai) and surface meteorological data to estimate E by: 1) introducing a simple biophysical model for canopy conductance (G_c), defined as a constant maximum stomatal conductance g_smax of 12.2mm s⁻¹multiplied by air relative humidity (R_{h …}

Fabrication And Characterization Of Dna-Loaded Zein Nanospheres, Mary C. Regier, Jessica D. Taylor, Tyler Borcyk, Yiqi Yang, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background: Particulates incorporating DNA are promising vehicles for gene delivery, with the ability to protect DNA and provide for controlled, localized, and sustained release and transfection. Zein, a hydrophobic protein from corn, is biocompatible and has properties that make it a promising candidate material for particulate delivery, including its ability to form nanospheres through coacervation and its insolubility under physiological conditions, making it capable of sustained release of encapsulated compounds. Due to the promise of this natural biomaterial for drug delivery, the objective of this study was to formulate zein nanospheres encapsulating DNA as the therapeutic compound, and to …

Runoff Nutrient Loads As Affected By Residue Cover, Manure Application Rate, And Flow Rate, Chance Thayer, John E. Gilley, Lisa M. Durso, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure is applied to cropland areas with varying surface cover to meet single‐year or multiple‐year crop nutrient requirements. The objectives of this field study were to: (1) examine runoff water quality characteristics following land application of manure to sites with and without wheat residue, (2) compare the water quality impacts of land application of manure to meet 0‐, 1‐, 2‐, 4‐, and 8‐year P‐based requirements for corn, and (3) evaluate the effects of varying runoff rates on runoff nutrient loads. Three 30‐min simulated rainfall events, separated by 24 h intervals, were applied at an intensity of 70 mm h^{‐1 …}

Quantification And Heterogeneity Of Infiltration And Transport In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Peter Q. Storm, Brian E. Haggard, Todd Halihan, Ronald B. Miller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In order to protect drinking water systems and aquatic ecosystems, all critical nutrient source areas and transport mechanisms need to be characterized. It is hypothesized that hydrologic heterogeneities (e.g., macropores and gravel outcrops) in the subsurface of floodplains play an integral role in impacting flow and contaminant transport between the soil surface and shallow alluvial aquifers which are intricately connected to streams. Infiltration is often assumed to be uniform at the field scale, but this neglects the high spatial variability common in anisotropic, heterogeneous alluvial floodplain soils. In the Ozark ecoregion, for example, the erosion of carbonate bedrock (primarily limestone) …

Berm Method For Quantification Of Infiltration And Leaching At The Plot Scale In High Conductivity Soils, Derek M. Heeren, Garey A. Fox, Daniel E. Storm

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Measuring infiltration and leaching at the plot scale is difficult, especially for high hydraulic conductivity soils. Infiltration rate has been indirectly calculated at the plot scale by comparing surface runoff to rainfall. Direct measurement of infiltration and leaching beyond the point scale is typically limited to locations where land forming has been performed, e.g. infiltration ponds and fields with basin irrigation. The standard method for field measurement of infiltration is a double ring infiltrometer, which is limited in size (typically 30 cm diameter). In this research, a new method is proposed that uses a temporary berm constructed of a water …

Field Scale Modeling To Estimate Phosphorus And Sediment Load Reductions Using A Newly Developed Graphical User Interface For Soil And Water Assessment Tool, Aaron R. Mittelstet, Erin R. Daly, Daniel E. Storm, Michael J. White, Greg A. Kloxin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Streams throughout the North Canadian River watershed in northwest Oklahoma, USA have elevated levels of nutrients and sediment. Soil and Water Assessment Tool (SWAT) was used to identify areas that likely contributed disproportionate amounts of Phosphorus (P) and sediment to Lake Overholser, the receiving reservoir at the watershed outlet. These sites were then targeted by the Oklahoma Conservation Commission (OCC) to implement conservation practices, such as conservation tillage and pasture planting as part of a US Environmental Protection Agency Section 319(h) project. Conservation practices were implemented on 238 fields. The objective of this project was to evaluate conservation practice effectiveness …

Whose Water Is It Anyway? Comparing The Water Rights Frameworks Of Arkansas, Oklahoma, Texas, New Mexico, Georgia, Alabama, And Florida, M. D. Smolen, Aaron R. Mittelstet, Bekki Harjo

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In most states surface waters, (streams, lakes, and coastal waters) are owned by the public. On the other hand, ground water may be privately or publicly owned. Because all waters are linked through the hydrologic cycle, and the hydrologic cycle is not confined within any geographic or political boundary, the question of ownership is generally replaced by one of who has the right to manage, divert, use, or sell the water.

Comparison Of 2-Way Versus Metered 3-Way Boom Shut-Off Valves For Automatic Section Control On Agricultural Sprayers, Ajay Sharda, Joe D. Luck, John P. Fulton, Timothy P. Mcdonald, Scott A. Shearer, Daniel K. Mullenix

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Modern spray rate controllers along with technologies such as automatic section control (ASC) provide benefits such as overlap reduction on agricultural sprayers. However, product (liquid) dynamics within the boom plumbing affect off-rate errors and application uniformity during rate changes and ASC actuation. Therefore, this study was conducted to compare nozzle flow stability and uniformity across the boom when using two different boom shut-off valves (2-way and metered 3-way) on an 18.3-m sprayer boom. Pressure transducers were mounted at 1) the boom manifold, 2) randomly at 12 nozzle bodies across the spray boom, and 3) upstream and downstream of the flow …

Selecting Sprinkler Packages For Center Pivots, Derrel L. Martin, William L. Kranz, Allen L. Thompson, Hong Liang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Center pivots are the primary method of irrigation across the U.S. Great Plains. Center-pivot irrigation is also the fastest growing method of irrigation in the U.S. and around the world. Pivots have the potential to be very efficient and uniform if sprinkler devices are properly selected for local field conditions. New water application devices provide for selection that minimizes runoff and controls droplet sizes to reduce evaporation and drift losses. We present updates to models for computing runoff potential based on characteristics of sprinkler devices and soil textural classes. A dimensionless solution to the Green-Ampt infiltration method for center pivots …

Sensitivity Of Grass- And Alfalfa-Reference Evapotranspiration To Weather Station Sensor Accuracy, Dana O. Porter, Prasanna H. Gowda, Thomas H. Marek, Terry A. Howell, Jerry Moorhead, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A sensitivity analysis was conducted to determine the relative effects of measurement errors in climate data input parameters on the accuracy of calculated reference crop evapotranspiration (ET) using the ASCE-EWRI Standardized Reference ET Equation. Data for the period of 1995 to 2008 from an automated weather station located at the USDA-ARS Conservation and Production Research Laboratory at Bushland, Texas were used for the analysis. Results

indicated that grass (ET_os) and alfalfa (ET_rs) reference crop ET were most sensitive to measurement errors in wind speed and air temperature followed by incoming shortwave (solar) radiation, and that data …

Evaluation Of A Rhodamine-Wt Dye/Glycerin Mixture As A Tracer For Testing Direct Injection Systems For Agricultural Sprayers, Joe D. Luck, Scott A. Shearer, Brian D. Luck, Fred A. Payne

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The purpose of this study was to provide valuable insight regarding the use of Rhodamine WT (red) dye as a tracer for evaluating injected concentrations. More specifically, the effects of mixing the dye with glycerin to simulate the viscosity of a pesticide (e.g., glyphosate) or injecting the dye/glycerin mixture into deionized (DI) versus tap water on developing appropriate calibration equations were evaluated. Test results indicated that mixing the dye in a solution of glycerin and DI water significantly affected absorbance measurements compared to the dye mixed solely in DI water. The error in estimating absorbance was 7.4% between the two …

Swat: Model Use, Calibration, And Validation, Jeffrey G. Arnold, Daniel N. Moriasi, Philip W. Gassman, Karim C. Abbaspour, Michael J. White, Raghavan Srinivasan, Chinnasamy Santhi, Daren Harmel, Ann Van Griensven, Michael W. Van Liew, Narayanan Kannan, Manoj K. Jha

Department of Agricultural and Biological Systems Engineering: Faculty Publications

SWAT (Soil and Water Assessment Tool) is a comprehensive, semi-distributed river basin model that requires a large number of input parameters, which complicates model parameterization and calibration. Several calibration techniques have been developed for SWAT, including manual calibration procedures and automated procedures using the shuffled complex evolution method and other common methods. In addition, SWAT-CUP was recently developed and provides a decision-making framework that incorporates a semi-automated approach (SUFI2) using both manual and automated calibration and incorporating sensitivity and uncertainty analysis. In SWAT-CUP, users can manually adjust parameters and ranges iteratively between autocalibration runs. Parameter sensitivity analysis helps focus the …

Soil Water Extraction Patterns And Crop, Irrigation, And Evapotranspiration Water Use Efficiency Of Maize Under Full And Limited Irrigation And Rainfed Settings, Koffi Djaman, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of full and limited irrigation and rainfed maize production practices on soil water extraction and water use efficiencies were investigated in 2009 and 2010 under center-pivot irrigation near Clay Center, Nebraska. Four irrigation regimes (fully irrigated treatment (FIT), 75% FIT, 60% FIT, and 50% FIT) and a rainfed treatment were implemented. The crop water use efficiency (CWUE, or crop water productivity), irrigation water use efficiency (IWUE), and evapotranspiration water use efficiency (ETWUE) were used to evaluate the water productivity performance of each

treatment. The seasonal rainfall amounts in 2009 and 2010, respectively, were 426 mm (18% below normal) …

Large-Scale On-Farm Implementation Of Soil Moisture-Based Irrigation Management Strategies For Increasing Maize Water Productivity, Suat Irmak, Michael J. Burgert, Haishun Yang, Kenneth G. Cassman, Daniel T. Walters, William R. Rathje, Jose O. Payero, Patricio Grassini, Mark S. Kuzila, Kelly J. Brunkhorst, Dean E. Eisenhauer, William L. Kranz, Brandy Vandewalle, Jennifer M. Rees, Gary L. Zoubek, Charles A. Shapiro, Gregory J. Teichmeier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Irrigated maize is produced on about 3.5 Mha in the U.S. Great Plains and western Corn Belt. Most irrigation water comes from groundwater. Persistent drought and increased competition for water resources threaten long-term viability of groundwater resources, which motivated our research to develop strategies to increase water productivity without noticeable reduction in maize yield. Results from previous research at the University of Nebraska-Lincoln (UNL) experiment stations in 2005 and 2006 found that it was possible to substantially reduce irrigation amounts and increase irrigation water use efficiency (IWUE) and crop water use efficiency (CWUE) (or crop water productivity) with little or …

Evaporative Losses From A Common Reed-Dominated Peachleaf Willow And Cottonwood Riparian Plant Community, Isa Kabenge, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Our study is one of the first to integrate and apply within-canopy radiation physics parameters and scaling-up leaf-level stomatal resistace (r_L) to canopy resistance (r_c) approach to quantify hourly transpiration (TRP) rates of individual riparian plant species—common reed (Phragmites australis), peachleaf willow (Salix amygdaloides), and cottonwood (Populus deltoides)— in a mixed riparian plant community in the Platte River Basin in central Nebraska. Two experimental years (2009 and 2010) were contrasted by warmer air temperature and presence of flood water in 2010. The seasonal average r_c values for common reed, …

P95. In Vivo Loads In The Cervical Spine: A Preliminary Investigation Using A Force-Sensing Implant, Rebecca A. Wachs, Mary Beth M. Grabowsky, Joseph C. Glennon, Eric H. Ledet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

BACKGROUND CONTEXT: It is estimated that up to 80% of the general population will experience at least one significant bout of low back pain in their lifetime. The leading known cause of low back pain is degenerative disc disease (DDD). Many established risk factors for low back pain and DDD are mechanical in nature and are often related to occupational activities, such as poor posture and frequent/heavy lifting. Altered mechanical loading in the spine has been shown to be a potential stimulus for disc degeneration. However, a link between occupational/environmental factors and intervertebral loading has never been demonstrated in vivo. …