VTechWorks Repository :: Browsing by Author "Marsh, Lori S."

Browsing by Author "Marsh, Lori S."

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4-H electric project leader's guide for junior electric energy curriculum
Marsh, Lori S. (Virginia Cooperative Extension, 1994)
This guide outlines the use of lesson plans developed for 4-H youth, ages nine to eleven, who are interested in learning about electric energy. The lessons have been divided into two units. The first unit, Basic Electricity, consists of four lessons that explore basic electrical concepts. The second unit, Applied Electricity, consists of five lessons that explore applications of electricity. The lessons should be completed in order, since each lesson builds on concepts presented in previous lessons. Because the curriculum is divided into two units, you need only commit to teaching a series of lessons designed to run for four to five meetings.
Composting Your Organic Kitchen Wastes With Worms
Marsh, Lori S. (Virginia Cooperative Extension, 2009-05-01)
Provides an explanation of vermicomposting, why it is useful, how to create and maintain the correct environment for worm based composting, and provides tips to troubleshoot a worm bin composter that is not preforming ideally.
A computer simulation model for wastewater management in an integrated (fish production-hydroponics) system
Singh, Sahdev (Virginia Tech, 1996)
Intensive fish production in a recirculating aquaculture system facility is a complex bioengineering operation involving a sensitive balance among physiological, water quality, and management components of the overall system. Warm and nutrient-rich wastewater discharged from controlled-environment fish production facilities is a loss of heat energy and nutrients in addition to being potentially harmful to the environment. The operators of such systems need sophisticated management tools if the operation is to be both commercially successful and environmentally friendly. Effluent heat and nutrients can be recovered using hydroponics in a greenhouse attached to the recirculating aquaculture system facility. A computer model was developed to simulate system performance and to help determine design parameters for an integrated fish production-hydroponics system. The aquaculture component of the model predicts (a) fish growth-dependent feeding, (b) diurnal metabolic waste production/accumulation in the fish culture water, and (c) quality, quantity and frequency of wastewater discharge. The hydroponics component computes optimum greenhouse size and models the performance of vegetable plants in terms of nutrient-uptake, water use, and growth. SUCROS and TOMGRO, plant growth models with modifications for water use and nutrient uptake, were used to simulate lettuce and tomato performance, respectively. To validate the plant models, experiments were conducted in a greenhouse utilizing aquacultural wastewater as the hydroponic solution to produce lettuce and tomatoes. Plant growth, water quality (nutrient-uptake), water use, and environmental conditions were monitored. Lettuce and tomato growth was accompanied with significant reductions in nitrogen and phosphorus levels of the wastewater. Water use by plants strongly depended on solar radiation and plant growth stage. At harvest, nine-week-old lettuce weighed 160 g/plant (average) at a density of 40 plants/m². Tomato yielded 2.4 kg/m² after 17 weeks. However, the tomato fruits did not reach maturity during this time. After 20 weeks, the tomato yield was 3.1 kg/m² and some fruits showed maturity. The use of the model as a management tool for making decisions on optimum greenhouse area for a given recirculating aquaculture system size is demonstrated. The effect of fish stocking density and greenhouse heat loss factor on the optimum greenhouse size are also demonstrated. For an optimum greenhouse size, water use and nutrient-recovery from the effluent by lettuce and tomato plants are quantified.
Cover crop residue effects on machine-induced soil compaction
Ess, Daniel R. (Virginia Tech, 1994-07-05)
Crop production systems which utilize the biomass produced by rye (Secale cereale ) to suppress weed growth and conserve soil moisture have been developed at Virginia Tech. The success of alternative, reduced-input crop production systems has encouraged research into the potential for breaking the traffic-tillage cycle associated with conventional tillage crop production systems. The fragile residues encountered in agricultural crop production, whether incorporated into the soil or distributed on the soil surface, provide minimal protection against compaction by wheeled vehicles. The potential of an intact cover crop to reduce machine-induced effects on soil properties that affect primary crop growth was the subject of this study. A randomized complete block experiment was conducted at the Whitethorne Farm in Montgomery County, Virginia. One set of plots was arranged on a terrace adjacent to the New River in a fine, mixed, mesic, Aquic Argiudolls. Another set of plots was arranged on an upland site, a river terrace tread, in a fine-loamy, mixed, mesic, Typic Hapludults. Three rye cover crop treatments were examined. In one, a live cover crop was completely undisturbed prior to tracking by a wheel-type tractor. In another, the cover crop was chemically desiccated, and in the third treatment, all above-ground biomass was removed from plots prior to machine traffic. The treatments permitted investigation of the effects of crop condition on machine-induced soil compaction and the contribution of root reinforcement to the alteration of soil response to machine traffic. A fall-tilled fallow treatment served as an experimental control. Three levels of traffic were investigated: one pass, three passes, and five passes. Undisturbed soil core samples were analyzed to determine machine-induced effects on dry bulk density, pore size distribution, and saturated hydraulic conductivity. The treatments affected soil response to machine traffic. The cover crop treatments altered the soil-plant microenvironment, affecting soil parameters that influence compactibility. Soil compaction was attenuated by the reinforcing effect of a network of undisturbed roots within the soil. There was no convincing evidence that above-ground biomass contributed directly to the reduction of machine-induced compaction effects. Soil response to machine traffic was limited to the uppermost 15 cm of the soil profile.
Dry matter loss and compositional analysis of large switchgrass round bales during ambient storage in Virginia
Brumback, Clay T. (Virginia Tech, 1995-08-07)
Two varieties of switchgrass, Cave-N-Rock and Alamo, were baled into 1.8-m diameter by 1.2-m wide round bales and stored outside for 12 months. String-wrapped bales were stored on sad and net-wrapped bales on rock. Six bales (three-string-wrapped, three netwrapped) were destructively sampled at four, eight, and 12 months. Samples were collected for moisture content and compositional analysis. As expected, there was a large moisture content gradient from the weathered layer to the inner core, depending on drying conditions since the last precipitation. In one instance weathered layer moisture content was three times the core moisture content Netwrapped bales were drier than string-wrapped bales. Negligible dry matter loss (DML) was reported at four and eight months for Cave-N-Rock with DML no greater than 7% after 12 months of storage. Calculated DML was highly variable but no more than 16% of original dry matter after 12 months of storage for Alamo. For one set of six bales (Cave-N-Rock, sampled at eight months), the calculated dry matter loss was negative (meaning the bales gained dry matter during storage). This result is physically impossible and illustrates the difficulty in accurately measuring dry matter loss. DML was less for net-wrapped bales on rock than string-wrapped bales on sod.
Economics of greenhouse heating with a mine air-assisted heat pump
Marsh, Lori S.; Singh, Sahdev (American Society of Agricultural and Biological Engineers, 1994)
An analysis of the economics of greenhouse heating with a heat pump coupled with an inactive deep mine is presented. Several heat pump and conventional gas-fired heater combinations (hybrid systems) were evaluated using a computer model to perform thermal and economic analyses. A 10 x 30 m, double-polyethylene-covered greenhouse, located in Charleston, West Virginia, was assumed for this analysis. Heat pumps with sufficient capacity to maintain 21 degrees C inside the greenhouse for outside temperatures ranging from 0 to 20 degrees C (in 2 degrees degree increments) were modeled. For each heat pump capacity, it was assumed that the additional heat energy required to maintain the specified inside temperature (when outside temperature fell below the heat pump design temperature) was supplied by a natural gas-fired heater. Life-cycle cost analysis was employed to compare greenhouse heating alternatives. The hybrid system offers lower operating costs than a conventional system for any outside design temperature. However, when initial cost is also considered, the hybrid system has a higher life cycle cost for heat pump design temperatures in the range 0 to 18 degrees C and a coefficient of performance (COP) of 3. As the heat pump COP increases beyond 3, the hybrid system becomes economically feasible, showing a lower life cycle cost than a conventional natural gas-fired system.
Electricity
Marsh, Lori S. (Virginia Cooperative Extension, 2014)
In these lessons, students will investigate and understand the characteristics of electricity.
Energetics of a sustainable crop-livestock system
Kern, James D. (Virginia Tech, 1994-05-15)
This study compares the energy utilization of two systems for producing cattle of desirable slaughter weight and grade from weanlings. Both systems produce beef cattle as a primary output; various types of baled hay are produced as a secondary output. One system uses generally accepted, "best management practices" while the other uses experimental, sustainable agriculture techniques. Since the adoption of new practices in agriculture often hinges on economics, an economic comparison is also presented. Beef produced in the sustainable system required 32% less energy per kilogram than that produced in the conventional system. However, baled alfalfa produced in the sustainable system required 8% more energy per kilogram than the alfalfa grown in the conventional system. When all types of hay were considered, the sustainable system used 7% more energy to produce one kilogram of baled hay. To compare the energetics of the two systems on a whole farm basis, the amount of energy required to produce one dollar of return was calculated. The sustainable system required 12.4 megajoules to produce one dollar of return, while the conventional system required 17.1 megajoules to produce the same return. Although economic returns on beef and alfalfa production were comparable in the two systems studied, the conventional system showed greater returns on the whole farm, due to a greater export of baled hay.
Evaluation of Nutrient and Pathogen Losses From Various Poultry Litter Storage Methods
Habersack, Mathew James (Virginia Tech, 2002-07-23)
Considerable concern has developed over the possible pollution from poultry litter storage methods. This study was conducted to evaluate three different storage scenarios; covered stockpiles, uncovered stockpiles, and litter sheds. The stockpiles were monitored over two rainfall simulation events, in both the Ridge and Valley and the Piedmont physiographic provinces, with both surface and subsurface flows analyzed. An observational study, where subsurface water was sampled for a nine-month period was conducted using six litter sheds, three in each of the above provinces. Samples were analyzed for nutrients, fecal coliforms, and solids. Concentrations of NHx, TKN, OP, TP, VSS, and FC in surface runoff from uncovered litter piles were all statistically higher than that from covered piles, with NO3 being the exception. However, increased runoff volumes originating from the covered litter piles caused mass loadings from both covered and uncovered piles to be similar enough that statistical significance was not obtained, except in the case of FC. Soil water samples from litter stockpiles did not show a statistically significant treatment effect for concentration data, but uncovered piles did exhibit higher nitrogen concentration estimates than the covered piles. Sample collection frequency showed a statistically significant increase in the number of samples that could be obtained from the edge lysimeter under uncovered litter piles from the Piedmont experimental site. This result indicates uncovered piles are releasing the precipitation absorbed during the rainfall simulation into the sub-surface environment. In the storage shed study, a greater number of samples were collected per attempt at the Piedmont sheds compared to those at the Ridge and Valley site. While both areas were undergoing a significant drought, Piedmont porous-cup lysimeters yielded samples 63% of the time, compared to 10% for Ridge and Valley lysimeters. Lysimeters located near the edge of the shed were also more likely to yield a sample than those in the center or a background location. Unknown interferences within the litter shed samples prevented three laboratories from obtaining valid nutrient concentrations.
Finite element analysis of pre-ROPS tractor axle housing strength
Wen, Dongfang (Virginia Tech, 1994)
Tractor rollover protective structures (ROPS) have been found effective for protecting people from serious injury or death when tractors overturn. Extension agricultural engineers and safety specialists are promoting the retrofitting of ROPS on pre-ROPS tractors. ROPS, meeting to ASAE standards, are available for these older tractors. However, effective protection not only depends on the proper design of ROPS, but also on the structural adequacy of the rear axle housing on which ROPS are mounted, and on the means of attachment. Adequate information on the strength of pre-ROPS tractor axle housings 1s still lacking. A research project to develop a technique for determining the suitability of tractor axle housing when adding ROPS to pre-ROPS tractors was initiated by the Biological Systems Engineering Department at Virginia Tech in 1991. A finite element procedure was developed for the rear axle assembly of John Deere 720 tractor and models were built with a commercial software ANSYS Engineering Analysis Program. The models were employed to analyze the stress distributions under the static, crush, and dynamic ROPS tests recommended by ASAE. Laboratory tests were conducted to validate the models, and to assess the suitability of the shell element model and the general solid element model. Results of the analyses show that the rear axle housing assembly of John Deere 720 tractor has a safe margin for the static and crush tests under the condition of this study. Results also show that can support the dynamic test if the ROPS is mounted with a larger contact area with the axle assembly. The study concluded that the finite element procedure is effective to assess the strength adequacy of tractor axle housing and to determine the feasibility of retrofitting ROPS on pre-ROPS tractors.
Land Application of Broiler and Turkey Litter for Farming Operations Without a DEQ Permit
Marsh, Lori S.; Mullins, Gregory L.; Habersack, Mathew James; Collins, Eldridge R. Jr. (Virginia Cooperative Extension, 2009)
This publication is intended to provide guidance on land-applying poultry litter in an environmentally-sound manner.
Manure Spreader Calibration for Rear-discharge Equipment -- Handling Solid and Semi-solid Manures and Poultry Litter
Marsh, Lori S.; Mullins, Gregory L.; Ambler, Scott; Heidel, Richard D. (Virginia Cooperative Extension, 2009)
Discusses calibration methods of manure spreaders.
Pumping Water from Remote Locations for Livestock Watering
Marsh, Lori S. (Virginia Cooperative Extension, 2009-05-01)
Covers amount of water needed, pump sizes, and power sources for water pumps.
Regional Stormwater Management Facility System at the School of Veterinary Medicine, Blacksburg, Virginia
Wolter, Matthias (Virginia Tech, 1996-03-12)
Continuing development of the Virginia Tech campus is increasing downstream flooding and water quality problems. To address these problems, the University has proposed the construction of a stormwater management facility to control the quantity and quality of stormwater releases to Strouble Creek, a tributary of the New River. The overall goal of this project is to design a stormwater management facility proposed for the Virginia-Maryland College of Veterinary Medicine at Virginia Tech in Blacksburg, Virginia that will reduce present and anticipated downstream flooding and water quality problems. Specific objectives of the project are: * control of flooding in lower areas by reducing the peak discharge while disturbing existing wetlands as little as possible, * address removal of major NPS pollutants such as total phosphorus (TP), total nitrogen (TN), metals, organic compounds related to petroleum and gasoline, and suspended sediment (SS) from stormwater runoff, and * design of a dam system that is able to withstand all driving forces and constructed in accordance with governing regulations. The design requirement to limit wetland disturbance below one acre was maintained. The requirement set by officials of Virginia Tech is based on the Nationwide Permit 26 of the Wetland Regulations. An individual permit process is thus avoided. Considering this demand, however, the freedom of the stormwater management facility design was significantly restricted. Resulting from the previous restrictions mentioned, the facility will include two ponds in series - a lower, dry pond and an upper, wet pond. The stormwater management system is designed to reduce the peak discharge. The dry pond is designed to detain water only for a short period of time, as opposed to the wet pond which is designed to retain water, thereby maintaining a permanent pool of water, and to change the characteristics of runoff. The wet pond was chosen to be of an Extended Detention wetland type. Aspects such as the availability of suitable area and detention volume governed the decision to make use of this type of stormwater wetland. The constraint on a maximum possible water surface elevation due to the Veterinary School1s road embankment, which crest elevation is at 2023 ft, was considered in the design. The stormwater management facility was designed to meet water quantity control requirements and to address water quality benefits. Storm water management regulations intending to mitigate the adverse effects of land development to streams and waterways were met. Requirements to limit peak discharges from 2-year and 10-year events to existing discharge levels were achieved. Several outlet structures for each of the ponds were investigated. The structures proposed are a perforated riser/broad-crested weir for the wet pond and a proportional weir for the dry pond. They were chosen as a result of analyses on hydraulic performance, maximum water surface elevations, drawdown times, peak discharge rates, and pollutant removal capabilities. The average pollutant removal capability of 75% of TSS, 45% TP, and 25% TN for an extended stormwater wetland, as found in the literature, is expected to be lower for the proposed facility, since the wetland-to-watershed-area ratio is considerably smaller (0.22%) than the required minimum ratio of 1%. However, other suggested desirable parameter for extended detention wetland systems such as required treatment volume, effective flow path length, and dry weather water balance will be maintained. The structural design of the dams was based on experience and research data. The dams are designed to consist of two zones, shell and core. The core extends as a cutoff trench 4 feet below the ground surface. Additionally, toe drain trenches and anti-seep collars along the pipe where penetrating the dam will be placed to collect and reduce seepage, respectively. Special considerations toward seepage problems were taken into account for both dams by placing a cutoff trench and a toe drain trench. Note: The appendix of this project report contains four AutoCAD files, that can only be viewed using AutoCAD.
Science Display & Demonstration
Marsh, Lori S. (Virginia Cooperative Extension, 2012)
This document presents the rules and judging criteria for 4-H science display and demonstration projects.
Skinless V-Notched Fillet Yields ofTilapia (Oreochromis)
Kirkup, S. P.; Marsh, Lori S.; Coale, Charles W. Jr. (Commercial Fish and Shellfish Technologies Program, Virginia Tech, 2004-06-01)
White hybrid tilapia (Oreochromis) produced in an experiment that determined the effects of various management practices on growth rate and feed conversion ratios were weighed, measured, and filleted at the conclusion of the growth trials. Regression analyses produced two models to predict fillet yields-one model that used the fish weight and length and a reduced model that used only fish weight. While the full model produced a somewhat smaller error, it was found to be impractical to use fish length to estimate fillet yield due to the difficulty in obtaining a length measurement. The full model also produced unreasonable estimates when extended beyond the limits of the data set. Using a paired t-test, fillet yields of males and females of equal weights were tested and were not found to be significantly different. This model provides a means of converting market price of tilapia fillets to a price for live fish, once processing costs are considered.
Treatment of Wet Fish Sludge with Vermicomposting
Mishra, Sudhanshu (Virginia Tech, 2003-08-29)
Aquaculture, the cultured production of fish, is growing at a rapid pace worldwide. The industry is generating approximately 140,000 cubic meter wastewater per year. For this industry to flourish, viable methods for treating the resulting waste stream must be identified. The various methods were tried by many researchers like sand filtration method, recirculating aquaculture system, intermittent filtration methods. The most of the industries use sand filtration methods for treating aquaculture wastewater and the problems associated: the reduction in hydraulic conductivity, accumulation of solid due to which anaerobic conditions developed. This study investigated possible treatment technologies for wastewater and sludge produced from Blue Ridge Aquaculture (BRA), an indoor, recirculating aquaculture facility where tilapias (Oreochromis) are raised. Research focused on the use of vermicomposting in conjunction with sand bed filtration to filter aquaculture waste and treat the resulting solids. Two experiments were conducted: a feedstock acceptability test and a filter bed test. The feedstock acceptability test evaluated the suitability of the fish sludge (mixed with cardboard) as a feedstock for the worms involved in the vermicomposting process. The results showed that as the percentage of fish sludge in the feed increased from 0 to 50%, there was a corresponding increase in the growth rate of E.fetida biomass. The filter bed test appraised the feasibility and effectiveness of incorporating vermicomposting in sand filter beds to directly treat aquaculture wastewater. Popular in early wastewater treatment systems, sand filtration has seen a resurgence in recent years. To test the potential for even more effective filtration, sixteen sand filter beds were established--twelve that included worms and four that did not. Wastewater (1.5 % total solids) from BRA was applied to the sand beds at loading rates of 400 to 1000 grams of volatile solids/m2/week. Filter beds containing worms exhibited no ponding over the 70-day experimental period. However, all units without worms failed (exhibited ponding) by the 24th day of operation. Removal efficiencies obtained from the filter bed study for total solids (TS), volatile solids (VS), total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus (TP), sulfate, chlorides, and ammonia-N were greater in filter beds with worms than beds without worms. The worms were crucial to maintaining porosity in the filter beds, hence keeping the filters functioning over time. Worm filter beds removed approximately 100% of the TS, VS, TSS and Ammonia-N, 90% of the TP, 50% of the chlorides, 80% of the sulfate and 70% of the COD. Maximum hydraulic conductivity of 35 cm/day was achieved at the maximum application rate. All the worm filter beds therefore had greater hydraulic conductivity than filter beds without worms. The potential impact is to treat the wastewater effectively, to increase the flow of water, and may be to maintain the aerobic conditions on the worm filterbeds.
Virginia 4-H School Enrichment: Scientific Inquiry
Marsh, Lori S.; Jamison, Kathleen (Virginia Cooperative Extension, 2014)
This curriculum helps youth understand the process of science and discover the excitement of finding answers for themselves.

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