Biomedical Engineering and Bioengineering Commons^™

Interactions Of Bacteria And Amoebae With Ocular Biomaterials, Thomas John

Cells and Materials

The use of biomaterials in periocular and intraocular sites has resulted in some ocular inflammations and infections which can result in vision-threatening ocular disease. This review addresses bacterial interactions with, and adherence to ocular biomaterials such as soft contact lenses, surgical suture materials, and intraocular lenses. In addition, adherence of Acanthamoeba to soft contact lenses is described, and the role of these lenses in the development of Acanthamoeba keratitis is discussed.

Evaluation Of The Images Of Specular Microscopy Of The Cells On Implanted Intraocular Lenses In Vivo, Kiyoshi Okada, Keiko Takahashi, Hiroaki Sagawa, Kuniomi Abe

Cells and Materials

Specular microscopy , an optical method to study the anterior segment of the eye, was applied to observe the cells on implanted intraocular lenses in vivo. The images from specular microscopy were evaluated by comparing the morphology of the same cells on intraocular lenses implanted in rabbit eyes by specular microscopy , light microscopy and scanning electron microscopy (SEM). The time lapse study in living human eyes and the optical evaluation of jts interference images were performed to elucidate its image formation.

The same giant cells, as observed in vivo by specular microscopy, proved to be multinucleated cells. It …

Stereoscopic Analysis Of Trabecular Bone Orientation In Proximal Human Tibias, K. N. Bachus, M. K. Harman, R. D. Bloebaum

Cells and Materials

The three-dimensional orientation of trabeculae is a key factor in determining the load carrying capabilities of cancellous bone. Previous biomechanical studies have shown that proximal tibias resected parallel to the articulating surface are stronger and stiffer than the contralateral tibias resected perpendicular to the long axis of the bone. However, morphologic evidence was not provided to help explain the mechanical differences.

To determine the orientation of the trabeculae in the medial condyle for both parallel cut and perpendicular cut specimens, a scanning electron microscope and stereoscopic techniques were used. Data showed that tibias cut parallel to the articular surface had …

A Comparative Study Of Bovine Pericardium Mineralization: A Basic And Practical Approach, Branko B. Tomazic, Chakwan Siew, Walter E. Brown

Cells and Materials

The biomineralization of bovine pericardium (BP) heart valve bioprostheses was investigated by simulation of the process under in vitro and in vivo conditions. The nature and composition of calcific deposits that formed in human heart valve bioprostheses were compared with the mineral formed on BP discs immersed in a calcifying medium or subcutaneously implanted into Sprague-Dawley rats. The early stage of experimental biomineralization in vitro took place on the surface only, while in vivo deposition appeared to be intrinsic, as documented by histological cross sections. The chemical composition of the initial mineral phase formed under in vitro conditions had a …

Mechanical And Barrier Properties Of Edible Corn And Wheat Protein Films, T. P. Aydt, Curtis Weller, R. F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Published methods for production of homogeneous edible films from com and wheat proteins were adapted. Barrier and mechanical properties of the edible films were evaluated with procedures commonly used on polymeric films. Mechanical property data included thickness, elongation, tensile strength, tear strength, and burst strength measurements. Barrier property data included water vapor, oxygen, and carbon dioxide gas transmission rate measurements. Homogeneous com and wheat protein films were found to have low tensile strengths, far less than cellophane. Com films were brittle while wheat films were elastic in comparison to cellophane. All three types of film had low permeabilities for dry …

A Cooperative Educational Program To Reduce Soil Erosion, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, David A. Biere, Susan Smydra Krotz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Eastern Nebraska, especially the northeastern portion, has a history of severe soil erosion, due in part to a predominance of steep slopes and highly erodible soils (12). While the average annual allowable soil loss ("T" value) for most of these soils is five tons per acre, some fields have annual soil erosion rates that exceed 100 tons per acre. The loss of topsoil is critical, of course, but erosion from cropland also results in the removal of fertilizers and pesticides, which degrades water quality.

Even though farmers are generally aware that soil erosion is a national problem, many …

Equipment For Ridge Planting, Elbert C. Dickey, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In ridge plant systems, crops are planted into ridges formed during cultivation of the previous crop.

Row cleaning devices on the planter push weed seed and residue lying on the soil surface from the ridge to the area between the rows, or row middles. The crop seed is planted into the old row in a cleanly tilled strip at a higher elevation than the row middles. A band application of herbicide behind the planter typically is used in the row for weed control. Crop cultivation controls weeds between the row and rebuilds ridges for the following year.

Ridge plant systems …

Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Elbert C. Dickey, Roger Kanable, Stewart W. Melvin, Charles A. Burr

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Estimating Percent Residue Cover Using the Line-Transect Method

The line-transect method is one of the easiest method to use in the field to determine the percent residue cover on the surface. Accurate measurement is necessary to determine if enough cover is present to comply with the conservation plan.

The following is a step-by-step procedure for using the line-transect method to measure the percentage of residue cover.

Step 1

Use a 100-foot or 50-foot measuring tape for measuring residue cover. Other measuring length or even knotted ropes can be used if the appropriate multiplication factor is used to calculate the percentage. …

Fertilization Of Crops With Feedlot Manure, Elbert C. Dickey, Gerald Bodman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The application of animal manure to farmland is an appropriate and environmentally sound management practice for most feedlot operators. Land application returns nutrients from manure to the soil and helps build and maintain soil fertility. In addition to containing nitrogen, phosphorus and potassium, manure contains trace "elements such as calcium, magnesium, iron and zinc. Manure has also been shown to improve soil tilth, increase water-holding capacity, lessen wind and water erosion and improve aeration. Land application of manure should be viewed as a means to utilize crop nutrients present in the manure for crop production rather than utilizing the land …

Subsoiling, Contouring, And Tillage Effects On Erosion And Runoff, Paul J. Jasa, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A study to evaluate the effectiveness of subsoiling on reducing soil erosion and water runoff from continuous com production was conducted. A rotating boom rainfall simulator was used on replicated treatments having either preplant in-row subsoiling or postplant between-row subsoiling used in both tilled and untilled surface conditions. Tilled and untilled treatments without subsoiling were used as checks. These six treatments were used up-and-downhill and on the contour.

Subsoiling reduced the rate of water runoff but did not significantly reduce the soil erosion rate after equilibrium had been reached between water application and runoff rates. Surface condition and farming direction …

Enhancing Soil Conservation Practice Adoption With Targeted Educational Programs, Elbert C. Dickey, David P. Shelton, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Two independent, but closely related, grant funded educational programs were developed and implemented to reduce soil erosion in selected areas of eastern Nebraska. Traditional extension programming methods as well as other more non-traditional approaches were used extensively to enhance soil conservation practice adoption. In one program, encompassing 220 000 ha (540,000 acre) of cropland, annual soil erosion was reduced by 2.3 million t (2.5 million ton) and annual fuel savings of 1.5 million L (390,000 gal) were achieved through a reduction in the number of tillage operations. In the second project, more than 93 000 m (305,000 ft) of terraces …

Performance Of Seedigated And Conventionally Planted Crops, W. S. Leander Jr., Derrel L. Martin, James R. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Seedigation is the use of a moving sprinkler irrigation system to broadcast seeds on the soil surface. Seed germination, plant characteristics and yield for grain sorghum, winter wheat and soybeans that were seedigated and conventionally planted are compared. When the seeding rates for seedigation were increased above that for conventional planting, and adequate moisture was available for germination, grain sorghum and wheat seedigated on tilled surfaces produced yields similar to conventionally planted crops. Seedigation of soybeans into fallow conditions, or when used as a relay crop, was unsuccessful. Shallow disking following seedigation did not improve germination or yield of grain …

Residue Management To Control Soil Erosion By Water, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Michael C. Hirschi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Erosion Process

Erosion of topsoil begins when water detaches individual soil particles from clod and other soil aggregates. A single raindrop may seem insignificant, yet collectively, raindrops strike the ground with surprising force. During an intense storm, rainfall can loosen and detach up to 100 tons of soil per acre and can be especially erosive when residue mulch or vegetation are not present to absorb their impact.

Two problems often occur during rainstorms. The rate of rainfall can exceed the rate at which water can enter the soil and raindrop impact forces can partially seal the soil surface. In …

Hydraulic Characteristics Of Rills, John E. Gilley, E. R. Kottwitz, J. R. Simanton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rill density and rill flow rates were determined during rainfall simulation tests conducted at 11 sites located throughout the eastern United States. A mean rill density of 1.0 rills/m was found for the study locations. From measurements of the relative distribution of flow rates, a procedure is identified for partitioning flow between individual rills.

Regression equations were developed for relating rill width and hydraulic roughness coefficients to flow rate. Equations were also derived for predicting mean flow velocity from visually determined measurements of advance velocity. Information reported in this study can be used to estimate hydraulic characteristics of rills.

Ridge Plant Systems: Fertility, Richard B. Ferguson, Charles A. Shapiro, Elbert C. Dickey, Gary W. Hergert

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Soil Sample

The starting point for any fertilizer program, regardless of the tillage system, is obtaining a representative soil sample. Without knowing which nutrients are needed, the questions of what fertilizer and how much to apply become irrelevant. Two types of soil samples should be obtained: the traditional, zero to 8-inch sample for general fertility (pH, phosphorus, potassium, organic matter, etc.) and deep, subsoil samples for nitrate. Subsoil samples for nitrate should be taken to a depth of at least 3 feet.

The problem of how to obtain a representative soil sample is particularly relevant in ridge-tilled fields. On …

Using The Line-Transect Method To Estimate Percent Residue Cover, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, Roger Kanable, Susan Smydra Krotz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop residue left on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. ~ Research in Nebraska and other Midwestern states shows ' that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by as much as one half of what it would be from residue-free conditions. Greater amounts of residue cover further limit soil erosion, Figure 1.

Residue reduces erosion in two ways. First, the residue dissipates raindrop impact energy, reducing the amount of soil that is detached. Residue also forms a …

Stress Cracking And Breakage Susceptibility As Affected By Moisture Content At Harvest For Four Yellow Dent Corn Hybrids, Curtis Weller, M. R. Paulsen, M. P. Steinberg

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Four hybrids of yellow dent com were harvested at three levels of moisture content. After drying, samples were analyzed for stress cracking and susceptibility to breakage in Wisconsin (WBT) and Stein (SBT) breakage testers. Significant differences in stress cracking and breakage susceptibility as determined with the WBT and the SBT were observed among the four hybrids. Breakage susceptibility as measured with the WBT and SBT significantly increased as the harvest moisture increased. Stress cracks increased significantly as harvest moisture increased within the drying air temperatures of 49, 71, and 93° C. WBT breakage susceptibility significantly increased as drying air temperature …

Adsorption Of Bromide Tracers Onto Sediment, John E. Gilley, S. C. Finkner, John W. Doran, E. R. Kottwitz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Information concerning hydraulic parameters on upland areas could be greatly expanded through the use of tracing techniques. If bromide is used as a tracer, adsorption of bromide onto sediment may be of concern. Therefore, a laboratory study was conducted to identify the effects of sediment content and initial bromide concentration on adsorption of bromide for selected soils.
When bromide solutions were used within the appropriate instrument measurement range, neither soil texture, liming, nor sediment content were found to significantly affect adsorption of bromide. In contrast to systems using fluorescent dyes, correction factors for estimating adsorption of bromide are unnecessary. Since …

Approach To Bioremediation Of Contaminated Surface Soils, J. L. Sims, Ronald C. Sims, J. E. Matthews

Biological Engineering Faculty Publications

Biological processes, including microbial degradation, have been identified as critical mechanisms for attenuating organic contaminants during transit through the vadose zone to the groundwater. On-site soil remedial measures using biological processes can reduce or eliminate groundwater contamination, thus reducing the need for extensive groundwater monitoring and treatment requirements. On-site remedial systems that utilize the soil as the treatment system accomplish treatment by using naturally occurring microorganisms to treat the contaminants. Treatment often may be enhanced by a variety of physical/chemical methods, such as fertilization, tilling, soil Ph adjustment, moisture control, etc. The development of a bioremediation program for a specific …

Irrigation Soybeans By Growth Stages In Nebraska, N. L. Klocke, Dean E. Eisenhauer, James E. Specht, Roger Wesley Elmore, Gary W. Hergert

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Irrigated soybean production in Nebraska spans a region with diverse soils and climates. Irrigators can easily adopt irrigation scheduling using a stage of growth for timing applications. However, simplifying assumptions, including soil water holding capacity, rainfall, stored soil water, and adequate irrigation system capacity, are implicit in the development of stage of growth irrigation scheduling recommendations. Reliance on these can lead to misapplication of irrigation water.
This project tested irrigation scheduling techniques for indeterminate soybean production in Nebraska, with stage of growth indicating the initiation of irrigation. The range of soils and climate in the study area gave a range …

A Simplified Equation For Modeling Sediment Transport Capacity, S. C. Finkner, M. A. Nearing, G. R. Foster, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sediment transport capacity for shallow overland flow was represented as a quadratic function of downslope distance using the assumption of a linear increase in overland flow discharge with downslope distance and an approximation to the Yalin equation for sediment transport capacity. The simplified equation for sediment transport applies to complex topography having uniform soil and management characteristics. The simplified equation accurately approximated the Yalin equation when calibrated using the average of the hydraulic shear stresses at the end of a constant slope reference profile and the end of the actual profile. The simplified equation is useful in deriving closed-form solutions …

Performance Of Solar-Assisted Modified-Open-Front Swine Nurseries, G. R. Bodman, M. F. Kocher, J. A. Deshazer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Performance data of two modified-open-front non-mechanically ventilated swine nurseries have shown that solar energy can be effectively utilized to maintain a productive environment within the animal space during cold weather (temperatures as low as -26°C ( - 15 °F). The nurseries feature a monoslope roof design and passive collector panels that also function as warm weather ventilation panels. An active solar-heating system uses a ground-level collector operated in conjunction with an in-floor solar heat distribution and storage system. The nurseries were designed to handle pigs weighing from 7 to 23 kg (15 to 50 lb). An average of 19% of …

Management Strategies To Minimize And Reduce Soil Compaction, A. J. Jones, R. A. Wiese, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nature has some built-in processes that reduce soil compaction. They include cycles of wetting and drying, and freezing and thawing.

In the last 20 to 30 years, farming practices have changed drastically. These farming changes have made it more difficult for nature to rejuvenate the soil environment to an optimum condition for crops. Performing field operations on wet soils, using multiple field operations to grow the same crop continuously, and eliminating meadow crops from crop rotations contribute to more extensive and deeper compaction.

Each farmer has the opportunity to make decisions that can keep soils from becoming compacted.

Adoption of …

Evaluation Of Irrigation Planning Decisions, Derrel L. Martin, James R. Gilley, Raymond J. Supalla

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A method is developed to determine optimal irrigation strategies for a single season using crop production functions which incorporate physically based coefficients. The relationship of yield to evapotranspiration is used to develop the yield-irrigation function. The physical parameters used in the production function can be determined from field measurements or various types of computer simulation. Using this approach, the optimal irrigated area and depth of water to apply can be related to prices, costs, and physical parameters. This produces a more general solution than commonly used production functions that depend on limited experimental results. The optimal irrigation depth and irrigated …

Surface Cover Provided By Selected Legumes, John E. Gilley, J. F. Power, P. J. Reznicek, S. C. Finkner

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The use of legumes in conservation tillage systems may yield several benefits including reduced erosion resulting from establishment of surface cover. The effectiveness in furnishing surface cover of 18 plant species seeded on three different dates was evaluated over an 11-month period. For several of the legume species, planting date significantly influenced maximum surface cover and the number of days required to reach maximum cover. For each of the planting dates, hairy vetch achieved maximum cover as rapidly as any other legume and maintained the greatest cover throughout the study period. Relationships for estimating legume surface cover from vegetative mass …

Germ Weight, Germ Oil Content, And Estimated Oil Yield For Wet-Milled Yellow Dent Corn As Affected By Moisture Content At Harvest And Temperature Of Drying Air, Curtis L. Weller, Marvin R. Paulsen, Stephen Mbuvi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A split-plot experimental design was used to determine the effect of moisture content at harvest and temperature of drying air on weight, oil content, and estimated oil yield of corn germs recovered from laboratory wet milling. The effects were determined for a high-yielding hybrid of yellow dent corn widely grown in the corn belt that was hand-picked and hand-shelled. Germ oil content decreased significantly as moisture content at harvest and temperature of drying air increased. Germ weight and estimated oil yield generally decreased as both moisture content at harvest and temperature of drying air increased from 17.2 to 29.6% and …

Enhancing The Adoption Of Soil Conservation Practices With Targeted Educational Programs, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, David A. Biere

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Two independent, but closely related, grant funded educational programs have been developed and implemented to reduce soil erosion in selected areas of eastern Nebraska, U.S.A. Traditional extension programming methods as well as other more nontraditional approaches have been extensively used. In one program, encompassing 220,000 ha of cropland, annual soil erosion has been reduced by 2.5 Mt and annual fuel savings of 1.5 ML have been achieved through a reduction in the number of tillage operations. During a one-year period in the second project, more than 81,000 m of terraces were constructed, which resulted in an annual soil erosion reduction …

The Cost Of Misapplication Of Herbicides, Robert Grisso, Elbert C. Dickey, Larry D. Schulze

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A field survey of 103 private herbicide applicators was conducted during the spring of 1986 in 12 central and eastern Nebraska counties. The results showed that only 30% of the cooperators were applying herbicides within 5% of their intended application rate. Twenty-six percent of the cooperators over-applied herbicides during a single application, with an average cost due to misapplication of $3.11/ha ($1.26/a). If these values were extended over Nebraska, $4.26 million are expended for extra herbicides which were not necessary. The average cost of over application was in excess of $570 per application. Forty-four percent of the cooperators under-applied herbicides …

Performance And Design Of Vegetative Filters For Feedlot Runoff Treatment, Elbert C. Dickey, D. H. Vanderholm

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Installation of a zero-discharge, runoff-control system is one method for solving potential water pollution problems from many feedlot operations. Even though the zero-discharge system is required by regulation in several states, this approach may be economically prohibitive for many small operations. An alternative is to install a vegetative filter system to adequately control the runoff so that violations of water quality standards will not occur during storm runoff. Vegetative filters are systems in which a vegetative area such as pasture, grassed waterways, or even cropland is used for treating feedlot runoff by settling, filtration, dilution, adsorption of pollutants and infiltration. …

Determining Crop Residue Cover With Electronic Image Analysis, Elbert C. Dickey, David P. Shelton, G.E. Meyer, K.T. Fairbanks

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop residue management is one of the best and most efficient soil conservation methods available to farmers. Determinations of the percentage of the soil surface covered with crop residue are often needed for: soil conservation research; erosion control demonstrations; and maintaining compliance with federal, state, or local soil conservation regulations. A number of methods can be used to estimate residue cover, however, many have limitations. To help overcome some of these limitations, a technique, which uses readily-available microcomputer-related hardware and standard video camera equipment has been developed to estimate crop residue cover from photographic slides. This procedure is relatively rapid, …