To see the other types of publications on this topic, follow the link: Agricultural industries Mathematical models.
Dissertations / Theses on the topic 'Agricultural industries Mathematical models'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Agricultural industries Mathematical models.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Guedes, Maria do Carmo Vaz de Miranda. "Mathematical models in capital investment appraisal." Thesis, University of Warwick, 1988. http://wrap.warwick.ac.uk/107492/.
Full text
2
Manning, Charles Roger 1956. "Infiltration parameters for mathematical models of furrow irrigation." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278286.
Full textAbstract:
The effort to improve furrow irrigation design and management by use of mathematical models is hampered by the difficulty of obtaining infiltration parameters that adequately describe the infiltration process in furrows. This difficulty is related to the effect on infiltration of the variability of wetted width of a furrow with depth. Detailed field measurements of twelve furrow irrigations were used to develop infiltration parameters based on three different assumptions regarding the variation of wetted width with depth. These infiltration parameters were used as input into a mathematical model of furrow irrigation, SRFR. Comparison of measured advance times, water surface elevations and volume of water infiltrated with these values computed by SRFR indicates that SRFR gives consistent results based on the input parameters.
3
Madramootoo, Chandra Alastair 1954. "An agricultural land drainage simulation model /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72017.
Full textAbstract:
A deterministic computer model was developed to continuously simulate the runoff from surface and subsurface-drained fields in the St. Lawrence lowlands. The model simulates all of the major hydrologic and hydraulic processes occurring both above and below the ground. Input data requirements include hourly rainfall, daily potential evapotranspiration, soil physical properties, field dimensions, open channel geometry and drainage system specifications.Events for the years 1978 to 1982 were simulated, to compare the runoff characteristics between 20 ha, clay loam, surface-drained and subsurface-drained fields. Further simulations were conducted to examine the hydrologic effects of wide-spaced, deep, parallel field ditches.
Hydrographs for the one-in-200-year storm were also simulated. All of the simulations confirmed that the peak flow rate on the subsurface-drained field was less than that of the surface-drained field. Longer times to peak and lag times occurred on the subsurface-drained field.
4
Perrone, Jim T. "Hydrologic modeling of an agricultural watershed in Quebec using AGNPS." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29763.pdf.
Full text
5
Lloyd, Tim. "Present value models of agricultural land prices in England and Wales." Thesis, University of Nottingham, 1992. http://eprints.nottingham.ac.uk/11753/.
Full textAbstract:
This study employs recently developed techniques in time series econometrics to estimate linear models of equilibrium price determination in a competitive market for durable assets. Motivating this study is the unstructured approach employed in previous land price research, where the theoretical model of agent behaviour is invariably mis-specified or left undeveloped and the empirical model prone to the problems of spurious regression. The joint issues of theoretical and statistical congruence play important roles here. Specifically, a theoretical model is developed in which market participants are assumed to price land using present value methods. At the market level this yields a reduced form expression of equilibrium price determination which can be estimated empirically using aggregate data for England and Wales. The concepts of error correction and cointegration are then investigated and applied to the land price model. A unique long run relationship is identified between real agricultural land prices, inflation and real agricultural rents. Taking account of inflation-hedging as a motivation for acquiring farmland, land prices are shown to be principally determined by the returns to land, as embodied by market rents. The empirical model is also congruent with theoretical predictions regarding the unit elasticity between asset prices and returns. The error correction representation of the cointegrating set indicates that the short run response of land prices to rent and inflation is larger than the long run response. Consequently, land prices initially overshoot their equilibrium values following changes in rents or inflation. The period of adjustment to long run equilibrium lasts around three or fours years. The long run real rate of discount on agricultural land is estimated at 3.6% confirming the widely held belief that real rates of return on farmland are low. Present value models incorporating naive, adaptive and rational expectations are also estimated and the adaptive model is favoured by the data.
6
Patterson, Katherine Liza. "Wealth accounts for agricultural land : a hedonic pricing approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0007/MQ29762.pdf.
Full text
7
Richard, Paul François. "A computer analysis of the flow of water and nutrients in agricultural soils as affected by subsurface drainage." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29171.
Full textAbstract:
A computer model was developed in order to determine the effects of drainage practices on nutrient losses from level agricultural soils.
The model performs a daily simulation of the vertical flow of water, nitrogen, phosphorus, and heat, and of the growth of crops. A water flow submodel calculates the depth of the water table based on daily predictions of evaporation, transpiration, flow to drains and ditches, and deep percolation. An original saturated-unsaturated flow algorithm is used to determine moisture infiltration, redistribution, and upward flow in the soil matrix, as well as bypassing flow in the soil macropores and horizontal flux between the soil matrix and the macropores, and surface runoff. Nutrient movement occurs by mass flow. Heat flow, nutrient biochemical transformations, and crop growth are determined by using well established relations.
Field tests were carried out for a period of two years on an experimental site in the Lower Fraser Valley of British Columbia. The water table depth was measured on a continuous basis. Grab samples of drainwater and observation wells were obtained periodically and analyzed for nitrogen (N0₃-N, NH₄-N, and TKN) and phosphorus (P0₄-P and TP). The field results show a decrease in the concentration of all nutrients over the sampling period, and provide evidence that denitrification and bypassing flow are important mechanisms affecting the nutrient balance of this soil.
These results were used to calibrate the model. An excellent fit of the observed water table profile and an adequate fit of the observed drain concentration of nitrate were obtained. The simulation revealed that bypassing flow is a very important transfer mechanism in this soil and must be included in order to obtain a satisfactory fit of the experimental data.
A sensitivity analysis of the model showed that the patterns of moisture flow have a predominant influence on the rate of nutrient leaching. In particular, it was found that the nutrient concentration in drain water is a strong function of the hydraulic conductivity of the soil matrix and of the horizontal distance between the soil macropores, which control the ratio of moisture flow in the soil matrix to the macropore flow and the lateral diffusion of nutrients between the soil matrix and the macropores.
The effects of four different drainage designs on nutrient losses were simulated over a period of two years for three different soils and two different nutrient distributions in the soil. It was found that there is a large difference between the amount of nutrients leached from drainage systems using different drainage coefficients. There was also a large difference in the response of two drainage designs based on the same drainage coefficient but using different depth and spacing of drains. Transient effects, as determined by the initial vertical distribution of the nutrients, were seen to remain dominant over the two year duration of the simulation.
The model was found to be useful in explaining the apparent contradictions found in the literature assessing the effects of subsurface drainage on nutrient losses. The results from the model show these effects to be strongly site and condition specific. Furthermore, the model shows that soils and drainage designs that produce similar volumes of drain flow may exhibit very different leaching responses, and that drainage designs equivalent from a hydraulic standpoint can be very dissimilar in their potential for leaching nutrients. The model provides a tool which can be used to determine the appropriateness of different drainage designs in soils where minimizing nutrient losses is critical.Science, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate
8
Kaharabata, Samuel K. "Non-disturbing methods of estimating trace gas emissions from agricultural and forest sources." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35903.
Full textAbstract:
Two approaches, one using an atmospheric diffusion model and the other an atmospheric tracer, were used to predict the source strength of trace gases from observations of the downwind concentration field. Both approaches do not disturb the prevailing environmental and physical conditions nor the existing biogenic processes. An analytical solution to the advection-diffusion equation was used to back-calculate the source strength from the downwind concentration measurements of (i) single and multipoint (4 and 16 points) trace gas (sulphur hexafluoride (SF6) and methane (CH4)) release experiments conducted over microplots over an open field, and (ii) single point source SF6 release experiments conducted over a forested terrain. Best predictions of the source strength (to within +/-20%) were obtained from concentration observations made along the centreline of the diffusing plumes with the predictions improving when observations at the mean plume height were used. The diffusion model was then used to compute footprint estimates for neutral and unstable conditions, for tower and aircraft based observation platforms above the forest. They showed spatially constrained footprints in the surface layer, due to effective vertical coupling, so that observations from towers and low flying aircraft must be expected to be very site specific, and scaling up to larger areas will have to be done with careful consideration of surface mosaics. Above-canopy sampling of trace gases to determine volatile organic compound emissions were then interpreted in terms of footprint considerations. This was accomplished by defining the upwind canopy areas effectively sampled under the given wind and stability conditions. The analysis demonstrated, for example, that the variability observed in measured isoprene fluxes could be accounted for by varying numbers of randomly distributed clumps of emitter species within a varying footprint. It suggested that heterogeneity of the forest canopy, in terSulphur hexafluoride was also used as an atmospheric tracer in order to estimate CH4 emissions from manure slurry and cattle housed in barns and feedlots. (Abstract shortened by UMI.)
9
Basak, Rishi. "Environmental management systems and the intra-firm risk relationship." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0034/MQ64316.pdf.
Full text
10
Arroyo, Jorge M. "Money and the dispersion of relative prices in the drug and apparel industries." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/28574.
Full text
11
Schmid, Wolfgang. "A farm package for MODFLOW-2000 simulation of irrigation demand and conjunctively managed surface-water and ground-water supply /." Diss., The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2004_287_sip1_w.pdf&type=application/pdf.
Full text
12
Maundu, Maingi. "The performance of the Canadian food, beverages and tobacco processing industries : an extension of the profit-cost margin model to a pricing model." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29576.
Full textAbstract:
This study was undertaken to achieve three major objectives:
1. to estimate an econometric structure-profitability model for Canadian food, beverages
and tobacco processing industries;
2. to estimate a structure-price model of the sector to compare with the profit model; and
3. to make inferences about the performance of the sector, with reference to market power and industry efficiency.
The above objectives were accomplished by comparing empirical regression results of the two models by using the following approach. First, the statistical significance of the estimated coefficients was used to determine which factors should be considered of importance in explaining performance. Secondly, the signs on the estimated coefficients were used to determine the direction of the influence of market structure on performance. Lastly, a comparison of the size and statistical significance of the difference in the respective
coefficients was used to determine which of the two performance indexes (profitability and prices) is most affected by market structure.
From the study four broad conclusions were arrived at. Seller concentration and advertising do have an increasing effect on profitability, but this influence does not derive from market power (price increases). Instead, increases in these factors appear to promote price competition. However, tariff protection has an increasing effect on both profitability and prices. Furthermore, the net effect of tariffs is significantly larger on prices than on profitability.
Industry growth and market isolation factors have an increasing effect on profitabilty. But they have no significant influence on relative prices. Exports have a decreasing effect on profitability and prices. Increases in input prices may lead to increases in ouput prices.
Two broad implications can be drawn from the above results. First, price competition and industry efficiency can be enhanced by (either condoning or encouraging) high market shares, advertising, exports and industry growth.
Secondly, although tariffs can increase industry profitability, they may also lead to relatively larger increases in domestic output prices. Similarly, changes in input prices may lead to increases in output prices. Therefore, high tariffs and input prices may serve as barriers to competition, and allow inefficiency to persist in an industry.Land and Food Systems, Faculty of
Graduate
13
Johnson, Terrence G. "A model of nitrate leaching from agricultural systems in the northern neck of Virginia." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/37887.
Full textAbstract:
A model (VTCROPS) was developed to simulate the long-term effects of nitrogen (N) leaching to groundwater in the Northern Neck region of Virginia, and ultimately to the Chesapeake Bay. VTCROPS simulates N fate and transport in a soil-plant-atmosphere continuum in a vertical slice between two crop rows, enabling consideration of nonuniform fertilizer placement and root growth patterns. VTCROPS models atmospheric, soil and crop subsystems. Atmospheric conditions (rainfall, temperature, solar radiation) may be directly input by the user or generated using a stochastic climatic generator. The soil subsystem simulates runoff, infiltration, drainage and soil-water redistribution, N immobilization, nitrification, mineralization, denitrification and advective N transport. The crop subsystem simulates plant N uptake, and vegetative and reproductive growth in response to soil and climatic factors, explicitly for maize or wheat. VTCROPS simulates soybean in a crop rotation empirically accounting for leaf area and root growth. The model is capable of simulating long-term cropping sequences under minimum and conventional tillage practices for continuous maize or for rotations involving maize, wheat, soybean and fallow.
Critical internal model parameters were calibrated through comparison of output to field data. The sensitivity of output to input variables was determined. Model output is most sensitive to the climatic variables. Model predicted crop performance variables — grain and total dry matter yields and N content — and soil N content were compared with available field data from two sites over a three year period for maize. Data from six sites over a one year period were tested for wheat. Predictions for maize and total N content were fairly accurate, with a tendency to greater error in dry years. Predictions for wheat were somewhat less accurate, but incomplete field data precluded determining the source of discrepancies.
Long-term model predictions, for two year crop rotations with minimum and conventional tillage, were evaluated by comparing performance variables with literature values. Appropriate responses were obtained for N transformation processes. Mass conservation for soil-water and N were good. Maize performance variables were within the range of literature values, and were higher under minimum till. Wheat yields and N contents were somewhat higher than values reported in the literature. Nitrogen load is correlated to drainage and water use over the short run, and to rainfall and drainage over longer periods. Minimum tillage did not increase N load to groundwater. Over a year nitrogen load was strongly periodic, with most leaching taking place from January through April. More than 50% of the N load over a rotation was lost during an extended fallow period that followed soybeans. Nitrogen load increased with fertilizer rates, however, N leaching fraction was optimal around rates of 150 — 200 kg/ha.
The model was applied to the Virginia counties of Richmond, Westmoreland, Lancaster, King George and Northumberland to assess the potential for long term N leaching to groundwater. Soil surveys indicated that 34 soil map units occurred within 123,000 hectares of cultivated land. In order to reduce the number of simulations, principal component analysis and cluster analysis were employed to subdivide the cultivated area into 10 land units based on different soil properties. Historical climatic data from the area was used to calibrate the stochastic climatic generator.
Analyses were performed to determine long-term crop performance and N loads to ground and surface waters in the study area over a 26 year period (13 rotations). Two management systems were applied to the land units. The first management system consisted of a rotation of minimum tilled maize, conventionally tilled wheat, minimum tilled soybeans and a fallow period. The second management system had a similar cropping sequence, but all crops were conventionally tilled. In both cases, fertilizer was applied at a rate of 150 kg-N/ha/crop. With the exception of two land units, mean yield, water use and N uptake over the simulation was fairly uniform among the land units. Runoff and drainage were highly variable between land units and over time within units. Mineralization, denitrification and N load were highly variable both between land units and over time. Nitrogen load ranged from 66 to 131 kg/ha/rotation between land units.
Long-term average N loads and N concentrations from the cultivated area and from the total area of the study region were estimated. For this analysis it was assumed that 80% of the cultivated area was under minimum till and 20% under conventional tillage. An area-weighted average of 5.4 million kg-N/ha/year or 29% of total N applied is discharged to groundwater with an average drainage concentration of 9.9 mg/L. The average N concentration from the study area (including uncultivated areas) to groundwater is estimated at 5.1 mg/L. Average N concentration to the Chesapeake Bay from all sources, after dilution with runoff is 4.5 mg/L which is lower than the drinking water standard for nitrate N of 10 mg/L.
The possibility of using sewage sludge as a replacement for, or in consort with N fertilizer was investigated for a typical land unit, under a conventionally tilled maize-wheat- soybean-fallow rotation. Simulations were conducted with 100%, 50% and 0% sludge (C—N ratio of 12). With fertilizer N augmenting the sludge, the total N input (250 kg/ha) was the same for each treatment. Mean yields were similar for 50% and zero sludge, but lowered by 10% and 16%, respectively, for maize and wheat with 100% sludge. Discrepancies in yields were attributed to the fact that mineralization rates of sludge are not high enough to supply the crop N requirement during periods of peak uptake. Nitrate leaching was reduced by 41 and 25% with 100 and 50% sludge applications, respectively.Ph. D.
14
Shen, Yunxiang. "Risk analysis and its application in mining project evaluation." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64009.
Full text
15
Carpentier, Line Chantal. "Agriculture and the environment : an economic-ecologic input-output model of the Canadian economy." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55482.
Full textAbstract:
The current environmental movement calls for a re-evaluation of many economic-ecologic relationships. The objective of this study is to identify industrial sectors and final demands most responsible for particular types of residual discharge and resource use. An economic-ecologic model was constructed for the Canadian economy from the Statistics Canada I-O as modified by Thomassin et al. (1992). This modified version with its 12 agricultural sectors and 16 food processing sectors is best suited for agricultural policy analysis. The model estimates national erosion, pesticide and fertilizer use as well as air and water pollutants, solid waste, and water use associated with specified economic activities.Two different scenarios were analyzed. In the first, the impact on both the economy and the environment from changes in the final demand for agricultural and food commodities was simulated. Each commodity's final demand was increased by $1 million and its impact compared to the other simulated results. The ten commodities studied yielded similar economic impacts, while their environmental impacts differed considerably. Changes in the demand for wheat and oilseeds had the largest environmental impacts.
In the second scenario, the effects of a $1 million increase in each final demand category were compared. This scenario focussed on markets rather than products. The construction, exports and personal expenditures categories were the greatest generator of wastes and the largest user of free resources. The exports category yielded twice as much erosion than personal expenditures and twenty times more than the next highest value (construction).
16
Fu, Yan. "Modelling of ducted ventilation system in agricultural structures." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60519.
Full textAbstract:
Air distribution ducts are used in the environmental control of livestock and poultry building as well as the conditioning of most agricultural produce.In order to simplify the approach to the design of ventilation ducts, a mathematical equation has been derived to describe the average air velocity of a duct.
The primary objective of the research work was to test goodness of fit of an equation describing the average air velocity of perforated ventilation ducts, under balanced as well as unbalanced air distribution: $V = H sb{o}{X over L} + (V sb{L}-H sb{o}) {X sp2 over L sp2}$.
This equation was successfully tested using data measured from 14 ducts of constant cross-sectional area, built of wood or polyethylene with outlets of various shapes and aperture ratios. Results indicated that aperture ratio and distance along the duct are the two most significant factors influencing the average duct air velocity values, but material and outlet shape had little effect.
17
Banik, Milon Marc. "Performance effects of strategic groups and task environments in food manufacturing industries : augmenting the Bain-Mason paradigm." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56672.
Full textAbstract:
The concentration-profits relationship of the Bain-Mason paradigm is tested and an alternative "augmented model" is proposed which includes dimensions of task environments of food industries and industry strategy variables. The environment is characterized in terms of Dess and Beard's (1984) dimensions: munificence, dynamism and complexity.The augmented model was found to be a better descriptor of factors affecting the performance of the food industries than the Bain-Mason model. Profitability was found to be positively related to industrial concentration, and negatively related to munificence and complexity. No significant relationship between dynamism and profitability was found.
Further studies on the performance of the food manufacturing industries should include the use of strategic group typologies based on strategic behaviour specific to the food industries. It is also recommended that investigations of industry environments be conducted using multivariate measures of munificence, dynamism and complexity.
18
Edelstein, Christopher. "Climatic conditions and storm hydrology of a small agricultural watershed." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1314224.
Full textAbstract:
Climatic conditions (precipitation, evapotranspiration, available soil moisture, and temperature) are important variables when considering cumulative storm streamflow for a watershed. The objective of this study was to determine what climatic conditions, if any, could be used to mathematically model cumulative storm streamflow for an extensively-drained small agricultural watershed in northwest Delaware County, Indiana. A water-level recorder was installed in Killbuck Creek during autumn 2002, spring, summer, and autumn 2003 and 2004. To determine discharge, velocity measurements were collected following US Geological Survey (USGS) methods and two rating curves (high and low flow) were constructed. Simple linear regressions were performed using cumulative streamflow as the dependent variable and precipitation, evapotranspiration, available soil moisture, temperature, and runoff as independent variables. Multiple linear regressions were used to examine combinations of the independent variables. Cumulative streamflow was most related to precipitation (r2 = 0.23 and p < 0.001) and least related to temperature (r2 = 0.03 and p < 0.5). The multiple linear regression from the combination of precipitation, runoff, and temperature provided the most accurate cumulative streamflow simulation (R2 = 0.53 and p < 0.001). Multiple linear regressions using climatic variables can be used to estimate cumulative streamflow for an agricultural watershed.Department of Natural Resources and Environmental Management
19
Mok, Pik-yin, and 莫碧賢. "Evolutionary optimisation of production-control systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B29751020.
Full text
20
Land, Miriam L. "On measuring differential yielding abilities of wheat cultivars over varying environments." Thesis, Kansas State University, 1986. http://hdl.handle.net/2097/9925.
Full text
21
Taillon, Kate. "Modeling surface complexation relationships in forest and agricultural soil." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82435.
Full textAbstract:
The adsorption behaviour of trace metals in soil may provide us with a way to more accurately predict and assess the toxicity of metals in the environment. This thesis reports efforts to apply surface complexation modeling to agricultural and forest soil and to relate model parameters to common soil properties. This study considered Ca, Cd, Cu, Pb and Zn but the methods here could be applied to other metals. In Chapter 2, the surface charge and adsorption behaviour of a set of Ap horizons was characterised using back-titration and batch adsorption techniques. With the objective of simplifying the application of the NICCA model to surface charge and cation adsorption in whole soils the parameters of the NICCA model were related to soil properties (Chapter 3). Four of the six surface charge parameters could be predicted from soil properties and this enabled me to reasonably predict the surface charge of a second group of soils from soil properties. These results suggest that it is possible to make reasonable predictions about the surface charge and adsorption behaviour of a given type of soil using some easily measurable soil properties and a set of generic NICCA adsorption parameters for that soil type. In Chapter 4 this idea is applied to the determination of lime requirement for the agricultural soils.
22
Mousavizadeh, Mohammad Hassan. "Integration of a geographic information system and a continuous nonpoint source pollution model to evaluate the hydrologic response of an agricultural watershed." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0015/NQ44524.pdf.
Full text
23
Gollamudi, Apurva. "Hydrological and water quality modeling of agricultural fields in Quebec." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98710.
Full textAbstract:
Two tile-drained agricultural fields in the Pike River watershed of Southern Quebec were instrumented in October 2000 to monitor phosphorus and nitrate concentrations in surface runoff and tile drainage. Data collected from these sites were used as the primary input to test a GIS-based hydrological and water quality simulation model (ArcView SWAT2000) at the field scale. Surface runoff, subsurface flow, sediment yield, nitrate loads and phosphorus loads were the principal parameters evaluated by the model. The SWAT model was calibrated using data collected in the year 2002 while 2003 data was used for validating the model. Particulate phosphorus and total dissolved phosphorus loads in streamflow were also simulated using SWAT and compared with field measurements.A sensitivity analysis showed that curve number, available soil water content and soil evaporation factors significantly influenced water yield simulations while model performance for water quality parameters was governed mainly by the accuracy of simulating field operations such as fertilization and tillage. The monthly coefficients of performance after calibration ranged from being very good for some parameters (0.27 to 0.66 for total water yield; 0.38 to 0.67 for total phosphorus; and 0.23 to 0.89 for sediments) to being inconsistent for others (0.44 to 2.28 for subsurface flow; 0.63 to 4.36 for surface runoff; and 0.66 to 1.35 for total nitrate loads). Overall, it was found that SWAT results on a seasonal scale were generally more reliable whereas daily or monthly simulations could be improved by using a longer calibration period or incorporating model changes. Short-term impacts of implementing different best management practices for tillage, crop rotation and fertilization were also evaluated using the validated SWAT model. It was found that conservation tillage of corn coupled with pasture or soybean rotations can reduce total phosphorus loads in the range of 25-50% over conventional tillage with corn.
24
Li, Zhe 1974. "The environmental Kuznets curve reexamined for CO₂ emissions in Canadian manufacturing industries /." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80319.
Full textAbstract:
Recent studies of the environmental Kuznets curve raise questions regarding the relationship between environmental indicators and GDP and the fundamental reasons that explain this relationship. In response, this thesis presents one-sector and two-sector models to analyze the alternative causal relationships between an environmental indicator and GDP at different stages of economic development. These models analyze how economic scale, technology, preferences, and economic structure influence the causality and shape of the relationship. These theoretical studies are followed by two empirical studies. The first tests the causal relationship between CO2 emissions and GDP in Canadian manufacturing industries. The second explores several factors as the fundamental causes that influence the CO2 emissions in the same industries. Factors, such as economic scale, preferences, technological progress, structural change, and energy input, are found to be crucial in the determination of CO2 emissions. The empirical results are positive, but there are data limitations. The empirical studies can be re-evaluated as more data becomes available.
25
Park, William N. "Analysis of repayment ability for agricultural loans in Virginia using a qualitative choice model." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91054.
Full textAbstract:
Agricultural loans issued to farmers in Virginia from the years 1980-1985 are examined to determine the factors which significantly predict repayment ability. Through a review of literature, extension meetings, conferences and informal conversation with agricultural lenders in the state, a list of financial variables and operation characteristics is compiled and analyzed. Results of the analysis are considered in terms of their immediate and potential assistance to lenders in making loan decisions.
Using data from various commercial banks, Production Credit Associations and Farmers Home Administrations throughout Virginia, a model is developed to determine repayment ability of a borrower. Results indicate that several factors are significant in determining this process. Financial ratios such as percent equity, current debt, cash flow I and cash expense-cash receipt are important in determining if a borrower will repay his loan as scheduled. A number of operation characteristics were also found significant. These include: the number of creditors of the borrower, the amount of diversification of the operation and the amount of non-farm income. The results of the study should prove to be a significant aid to lenders and implies need for further research in the loan repayment area.M.S.
26
Martello, Charles P. "NATO burden-sharing redefinition for a changing European threat /." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA242560.
Full textAbstract:
Thesis (M.S. in Management)--Naval Postgraduate School, December 1990.Thesis Advisor(s): Gates, William. Second Reader: Doyle, Richard. "December 1990." Description based on title screen as viewed on April 2, 2010. DTIC Identifier(s): NATO, Defense Planning, Industrial Production, Economics, Burden Sharing, Defense Industries, Sharing, Costs, Military Forces (Foreign), Military Forces (United States), Military Equipment, Mathematical Models, Military Reserves, Industrial Capacity. Author(s) subject terms: Burden-sharing, NATO. Includes bibliographical references (p. 75-80). Also available in print.
27
Serpa, Fabio Marcelo. "Estimativa de esforços em implementos de preparo de solos e adequação trator- implemento." [s.n.], 1997. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257345.
Full textAbstract:
Orientador: Paulo S. G. MagalhãesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
Made available in DSpace on 2018-07-22T22:28:40Z (GMT). No. of bitstreams: 1 Serpa_FabioMarcelo_M.pdf: 3262573 bytes, checksum: c7a35a0ab37b487969889f07c0065ea1 (MD5) Previous issue date: 1997
Resumo: O objetivo foi desenvolver um aplicativo computacional, capaz de estimar os esforços em implementos agrícolas e avaliar o seu desempenho comparando com resultados de campo de diferentes conjuntos trator-implemento. Estudou-se os modelos para cálculo de esforços em ferramentas de preparo de solos, diferenciando-se entre ferramentas largas como arados e grades e estreitas, como escarificadores e subsoladores, buscando o modelo mais adequado às condições brasileiras. Os modelos escolhidos foram alterados com base em estudos apresentados na literatura específica, na tentativa de torná-los mais abrangentes. Com a escolha dos modelos, iniciou-se a programação em linguagem C++, obtendo uma versão preliminar onde todas as informações necessárias para os cálculos são introduzidas pelo usuário. Uma segunda versão, elaborada com o aplicativo MicroSoft Fox Pró 2.6, foi elaborada, tendo como base bancos de dados com os parâmetros necessários ao cálculo, definidos na primeira versão. Estes dados incluem, além das propriedades mecânicas dos solos, características ponderais e dimensionais de tratores e implementos obtidos junto aos fabricantes. Como segunda etapa, realizaram-se testes de campo com três diferentes modelos de tratores, 6 implementos e três tipos de solos, buscando avaliar os resultados obtidos com o uso do programa. De forma geral, o aplicativo apresentou resultados satisfatórios, com excessão das grades de discos, cujo desvio médio observado superou 50 %. Este aplicativo pode ser utilizado como uma ferramenta de auxílio na tomada de decisões por agricultores, cooperativas, revendedores de equipamentos agrícolas e como uma ferramenta didática em treinamentos no setor agrícola e universidades
aAbstract: A software was developed to estimate soU tillage draught forces and the performance of the tractor-implement combination. Draught force models for narrow and wide tillage tools were studied. The objetive was to find the most adequate model for a large range BrazUian field conditions. Input data for the first version of the software, written in C++ language was manual. A later version of the software, written in MicroSoft Fox Pró 2.6, includes a data base for soU mechanical properties and tractor dimensional and ponderal information, as well as tool dimensions, obtained from trator and implement manufactures. Field validation of the models included three different tractors, five implements and three different soils. The results obtained with the software predictions are in an acceptable divergence from those from the field tests. This programme can be an useful tool for Agricultural Machinery mamagement as well as for educational purposes
Mestrado
Maquinas Agricolas
Mestre em Engenharia Agrícola
28
Ghebretsadik, Amanuel Habte. "Farm planning for a typical crop-livestock integrated farm : an application of a mixed integer linear programming model." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49965.
Full textAbstract:
Assignment (MSc) -- University of Stellenbosch, 2004.ENGLISH ABSTRACT: In an integrated crop-livestock production farm, the profitability and sustainability of farm production is dependent on the crop rotation strategy applied. Crop rotations have historically been applied to maintain long-term profitability and sustainabiliry of farming production by exploiting the jointly beneficial interrelationships existing among different crop types and the animal production activity. Monocrop (specifically wheat) growers in the Swartland area of the Western Cape are struggling to maintain long-term profitability and sustainability of the crop production, challenging them to rethink about the introduction crop rotation in the production planning. By making proper assumptions, this paper develops a mixed integer linear programming model to suggest a decision planning for the farm planning problem faced by an integratedcrop- livestock production farmer. The mathematical model developed includes crop production, dairy production and wool sheep production activities, which permitted the consideration of five crop types within a crop rotation system. By assuming that a farmer uses a cycle of at most three years, the crop rotation model was incorporated in the composite mixed integer linear farm planning model. In order to demonstrate the application of the mathematical farm planning model formulated, a case study is presented. Relevant data from the Koeberg area of the Swartland region of the Western Cape was applied. For each planning period, the model assumed that the farm has the option of selecting from any of 15 cropping strategies. A land which is not allocated to any of the 15 crop rotation strategies due to risky production situation is left as grass land for roughage purposes of the animal production. Results of the mathematical model indicated that farm profit is dependent on the cropping strategy selected. Additionally, animal production level was also dependent on the crop strategy appl ied. Furthermore, study results suggest that the profit generated from the integrated crop-livestock farm production by adopting crop rotation was superior to profit generated 1'1'0111 the farm activities which are based on monocrop wheat strategy. Empirical results also indicated that the complex interrelationship involved in a mixed crop-livestock farm operation play a major role in determining optimal farm plans. This complex interrelationships favour the introduction of crop rotation in the crop production activities of the farm under investigation. Crop production risk is the major risk component of risk the farmer faces in the farm production. In this study, risk is incorporated in the mixed integer programrnmg farm planning model as a deviation from the expected values of an activity of returns. Model solution with risk indicated that crop rotation strategy and animal production level is sensitive to risk levels considered. The Results also showed that the incorporation of risk in the model greatly affects the level of acreage allocation, crop rotation and animal production level of the farm. Finally, to improve the profitability and sustainability of the farm activity, the study results suggest that the introduction of crop rotation which consist cereals, oil crops and leguminous forages is of paramount importance. Furthermore, the inclusion of forage crops such as medics in the integrated crop livestock production is beneficial for sustained profitability from year to year.
AFRIKAANSE OPSOMMING: Wisselbou is baie belangrik om volhoubare winsgewindheid te verseker in 'n geintegreerde lewendehawe I gewasverbouing boerdery in die Swartland gebied van Wes-Kaap. "n Monokultuur van veral koring produksie het ernstige problerne vir produsente veroorsaak. In hierdie studie word 'n gemengde heeltallige liniere prograrnmerings-model gebruik om te help met besluitneming in sulke boerderye.Die wiskundige model beskou die produksie van kontant- en voer-gewasse (5 verskillende soorte) asook suiwel- en wol/vleis-produksie (beeste en skape) .Daar word aanvaar dat die boer "n siklus van hoogstens 3 jaar in die wisselbou rotasie model gebruik .. 'n Gevallestudie word gedoen met behulp van toepaslike data van 'n plaas in die Koeberg gebied. Die model aanvaar dat die produsent 'n keuse het uit 16 wisselbou strategic .Resultate toon dat winsgewindheid afhanklik is van die strategie gekies en dat wisselbou beter resultate lewer as in die geval van "n monokultuur.Dit wys ook dat die wisselwerking tussen diereproduksie en gewasproduksie baie belangrik is in die keuse van 'n optimale strategie. Die risiko in gewasverbouing is die belangrikste risiko factor vir die produsent.In hierdie studie word risiko ook ingesluit in die gemengde heeltallige model, naamlik as 'n afwyking van die verwagte opbrengs-waardes .Die model toon duidelik dat gewasproduksie en lewendehawe-produksie baie sensitief is ten opsigte van die gekose risiko vlak. Die studie toon ook dat 'n wisselbou program wat die produksie van graan (veral koring) .oliesade asook voere insluit belangrik is vir volhoubare winsgewindheid Die insluiting van klawers (bv "medics") is veral belangrik hier.
29
Reda, Hussein Murad Ali. "A theory for national industrial development presented in a system dynamics model." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/76481.
Full textAbstract:
The dissertation presents a system dynamics model for national industrial development in developing economies. A development system is defined by national boundary, components and activities. The system is represented by ten activity sectors grouped into three functional classes: (1) Two driving sectors comprising population and investment capital sectors; (2) Seven industrial sectors: resources, manufacturing, agriculture, physical infrastructure, services, technology, and social infrastructure; and (3) An outlet sector represented by a trade sector.
The model's general theory of industrial development dynamics is described by causal feedback loops. A causal feedback loop consists of two or more interrelated variables where a change in one of the loop's variables causes all others to change as well. The industrial development model's specific structure evolved by applying the causal feedback theory to the system activity sectors. The model is written in DYNAMO, a continuous system, computer simulation language.
A prototype model run illustrated the basic development process and possible effects of alternative policies. Several conclusions were drawn regarding sensitive system parameters and various development policies. In addition, three developing-country examples representing low, middle, and high income groups were evaluated. Recommendations about model use and system analysis were presented. The industrial development model is intended to aid during development analysis and planning phases.Ph. D.
30
Morand, Hugues. "The economic potential of the Quebec cropping sector to sequester carbon in agricultural soils /." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80335.
Full textAbstract:
This research simulates the response of the Quebec cropping sector to the introduction of carbon credit revenue which could be made available through the implementation of a greenhouse gas emissions trading and offset system in Canada. Eligible carbon sequestering practices investigated in the simulations include adoption of moderate tillage and no-till as well as the conversion to a permanent cover crop. Monetary demand for greenhouse gas emissions offsets from the cropping sector is endogenized in the objective function of the Canadian Regional Agriculture Model (CRAM) which has been modified to account for the simulations and for the disaggregation of the single crop region of Quebec into eleven sub-regions. Changes in the cropping sector induced by the introduction of seven different carbon price levels, ranging from $1/t CO2 to $100/t CO2, are compared to a baseline. Variables covered in the simulation results include: relative profitability of carbon sequestering crops/technology; adoption rates of moderate tillage and no-till; carbon sequestration levels; carbon credit revenue; cropping pattern, crop production and livestock.Results indicate that carbon sequestration in agricultural soils could only contribute a minor share of the total emission reduction in Quebec, even with very high carbon price levels. At a carbon price of $15/t CO2, it is estimated that changes in tillage practices and permanent cover would result in an additional 12,328 t CO2 per year sequestered by the cropping sector in Quebec. However, some regions display higher adoption rates of carbon sequestering practices than other regions and appear to be more responsive to the price incentive. The introduction of a monetary demand for GHGE offsets from the cropping sector induces some changes in terms of cropping pattern and crop production level, while it has almost no impact on the livestock sector.
31
Butler, David Geoffrey. "A model of adult moth emergence from overwintering pupae : an application to Heliothis armigera." Thesis, Queensland University of Technology, 2001. https://eprints.qut.edu.au/37096/1/37096_Butler_2001.pdf.
Full textAbstract:
Heliothis spp. are significant agricultural pests worldwide. Larvae of Heliothis amigera feed on a range of economically important agricultural crops in north eastern Australia, with high value crops such as cotton accounting for much of the economic loss. Winter diapause is a key element in the life cycle of Heliothis spp., allowing populations to survive periods of low temperature and low host availability. Rising spring
temperatures initiate diapause termination and normal pupal development resumes so subsequent larval populations can take advantage of spring hosts. The implications for area-wide management strategies of anticipating the pattern of spring emergence from
overwintering populations of Heliothis spp. provided the biological motivation for this study. The motivating example used here was a constant temperature study of Heliothis armigera development where both the timing of diapause termination and subsequent moth emergence were recorded. There was no evidence of a population wide constant lower development threshold as assumed in previous studies, but rather a declining proportion of individuals completing development at lower temperatures. This result is typical of a bioassay where in this case the toxin was temperature. A plausible model then assumes a genetically determined tolerance distribution of development thresholds throughout the population. The model then assumes a functional relationship of development above this random, unobservable component.
In the Heliothis dataset it is not possible to separate genetic and environmental components as an individual could not emerge repeatedly. However, in considering estimation procedures both the full model with the non-identifiable pure error component and a reduced model omitting this parameter are considered. The approach explored here may prove useful in other species (for example, a plant population of recombinant inbred
lines) where selection for genetic potential for the tolerance level of a stimulus or toxin is required.
Chapter 2 takes a data analytic approach, confirming earlier work suggesting that the two phases leading to post diapause adult Heliothis emergence are independent. A Gaussian density is accepted as a reasonable form for the tolerance distribution, which, when combined with an exponential development model beyond the threshold value,
leads to a truncated lognormal model for diapause termination times. In this two stage approach, a population level linear regression (conditional on individuals developing) on the log scale is used to estimate the parameters of the rate function.
Chapters 3 and 4 consider maximum likelihood and Bayesian methods, respectively, to jointly estimate the parameters in the model for phase I development. The likelihood
functions and hierarchical models for both full and reduced cases are considered. For the full model the maximum likelihood solution for the (confounded) independent error component goes to the boundary. The parameter estimates from the reduced model
are similar but not identical to those obtained in Chapter 2. The bootstrap was used to
estimate small-sample variances of the parameters and were found equivalent to those obtained from the observed information matrix after numerical maximisation of the
likelihood function. Bayesian models for phase I development were fitted using the BUGS software. In the
case of the full model there is no real evidence warning of the inestimable parameter beyond the obvious dependence on the prior. For the reduced model, BUGS gives estimates almost identical results to those of Chapter 2. Some key advantages to this approach include the ability to specify different distributional assumptions quite simply and the ease with which credible intervals for functions of parameters can be
calculated. Estimated relative individual threshold temperatures for each individual are derived from this model. Although only of curiosity value in this example, for the plant population mentioned above individuals could be selected on genetic merit using
this approach.
A composite model with a two parameter lognormal density and functional relationship
with temperature is developed for pupal development (phase II). The final models consider the convolution of the distributions of the two phases as a model for adult
emergence, firstly in the constant temperature case and secondly in a variable temperature regime through the cumulative hazard function. The model fits a field emergence study adequately and, to illustrate its utility in an area-wide management program, is extended spatially across southern Queensland using a spatially interpolated temperature profile. This highlights a strong north/south gradient but also an east/west gradient in emergence times, indicating potential migratory pathways and population pressures.
32
Granço, Gabriel. "Comércio intra-industrial brasileiro: análise dos determinantes através da equação gravitacional." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11132/tde-28062011-092438/.
Full textAbstract:
Este trabalho teve por objetivo determinar a influência das características dos países e indústrias no comércio intra-industrial brasileiro de produtos manufaturados, considerando fluxos de quantidades comercializadas ao ano, para o período de 2002 a 2006, através de estimativas de uma equação gravitacional adaptada à análise dessa forma de comércio. As variáveis explicativas são relacionadas ao tamanho de mercado, representado pela proxy LPIBij, diferenças entre as rendas per capita dos países, representadas pela proxy LdPIBpcij, e tarifas aduaneiras aplicadas pelos países importadores, LTarifas. Tais variáveis foram utilizadas para analisar o comércio intraindustrial e seus componentes horizontal e vertical. A fundamentação teórica para proceder à segmentação do comércio intra-industrial brasileiro, segundo tais características, foi derivada de trabalhos conduzidos por Falvey (1981), Helpman e Krugman, (1985) e Greenaway, et al. (1995). A mensuração do Índice de Grubel-Lloyd e a posterior separação dos componentes do CII utilizando valor unitário indicam uma composição do comércio intra-industrial brasileiro com forte predomínio do componente CII Vertical Inferior.Os resultados da estimação das equações gravitacionais, com a utilização dos dados em painel e a utilização de Poisson Pseudo-Maximum-Likelihood comprovou ser a mais adequada para a estimativa econométrica.Para o comércio intraindustrial total, os resultados indicaram que o tamanho de mercado, tem um efeito positivo sobre o fluxo de exportação dos produtos brasileiros com comércio intraindustrial (0,517), porém, as diferenças entre as rendas per capita dos países (-0,183) e tarifas aduaneiras dos países importadores (-0,356), são negativamente relacionados. Os resultados para o comércio intra-industrial vertical e horizontal apresentam os mesmos sinais que o CII total, com alteração na magnitude.This study aimed to determine the influence of characteristics for countries and industries in intra-industry trade (IIT) of Brazilian manufactured products, considering the annual trade flows for the period 2002 to 2006 and using a gravity equation adapted to analysis this form of trade . The explanatory variables are related to market size, represented by proxy LPIBij, differences between per capita incomes of countries represented by proxy LdPIBpcij, and tariffs imposed by importing countries, represented by proxy LTarifas. These variables were used to analyze the intra-industry trade and its horizontal and vertical components. The theoretical basis to make the segmentation of intra-industry in Brazil, according to such characteristics, was derived from studies conducted by Falvey (1981), Helpman and Krugman (1985) and Greenaway et al.(1995). The measurement of the Grubel-Lloyd index and the subsequent separation of components from IIT using unit value indicates that the brazilian intra-industry trade has a strong predominance of IIT Vertical Low quality. The results of the estimation of the gravitational equations with the use of panel data and the use of Poisson Pseudo- Maximum-Likelihood proved to be the most suitable for econometric estimation. The results for intra-industry total indicated that the market size, has a positive effect on the flow of exports of Brazilian products with intra-industry trade (0,517), however, the differences between per capita incomes (-0,183) of countries and tariffs in importing countries (-0,356) have a negative relation. The results for vertical and horizontal intraindustry trade have the same signals than intra-industry total but they differ in magnitude.
33
Johann, André Luiz. "Modelo preditivo fuzzy da mobilização do solo no sistema de plantio direto." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-29062016-091351/.
Full textAbstract:
As culturas do milho e da soja respondem pela maior parte da produção nacional de grãos, predominando o sistema de plantio direto. Para uma semeadura direta de qualidade, o bom aterramento do sulco é indispensável, pois garante um ambiente adequado às sementes. Neste sentido, é importante estimar a mobilização de solo promovida por uma haste sulcadora estreita durante esta operação. O modelo analítico existente visa representar a mobilização do solo no sistema de plantio convencional. Como consequência, há situações em que este não pode se aplicado, como no caso de hastes sulcadoras estreitas utilizadas em semeadoras de plantio direto. Nestas situações, o mecanismo de falha do solo pode se alterar, assumindo um comportamento não modelado na literatura. Essa pesquisa propõe um modelo fuzzy capaz de representar estas situações, aproveitando conhecimento da teoria de mecânica dos solos e da análise de resultados experimentais. No modelo proposto, parte das regras descrevem situações não abrangidas pelo modelo analítico, as quais foram formuladas a partir da estimativa das prováveis áreas de solo mobilizado. O modelo fuzzy foi testado com dados de experimentos conduzidos durante a pesquisa, em duas condições de granulometria de solo (arenoso e argiloso). O modelo proposto reproduziu as tendências observadas nos dados experimentais, mas superestimou os valores de área observados, sendo esse efeito bem mais intenso para os dados do experimento em solo arenoso. A superestimativa ocorreu devido à soma de diversos fatores. Um deles é a diferença entre as leituras experimentais, as quais consideram apenas o solo realmente movimentado, e a premissa do modelo analítico, que considera toda a área de solo incluindo aquela cisalhada, porém não mobilizada. Outro fator foi devido ao efeito do disco de corte da palha, que pré-cisalha o solo à frente da ferramenta. No ensaio em solo arenoso os valores observados de área de solo mobilizado foram menores que os esperados, intensificando o efeito de superestimativa do modelo fuzzy, sendo que este efeito não representa uma deficiência deste modelo.Soybean and corn crops account for the majority of Brazilian crop production, predominantly under no-till system. A high quality no-till seeding requires adequate furrow finishing to ensure a suitable environment for seed germination and emergence. Therefore, it is important to estimate furrow soil mobilization promoted by a chisel opener during seeding operation. Existing analytical models aim to represent soil mobilization in conventional tillage. As result, there are situations which the model cannot be applied, such as the case of chisel opener of no-till seeders. Under these situations, soil failure mechanism may change assuming a behavior not modeled by other studies yet. This research proposes a fuzzy model to represent these situations, taking advantage of knowledge obtained from soil mechanics theory and analysis of experimental data. In the proposed model, part of the rules describes situations not covered by the analytical model, which were formulated based on the estimation of possible mobilized soil areas. The fuzzy model was tested using data from experiments for two conditions of soil particle size (sandy and clay). The model simulated trends observed in the experimental data but overestimated observed values of area, which effect was much more intense on sandy soil experiment. The overestimation was due a sum of factors. One is the difference between experimental and modeled data, the first only consider the really mobilized soil, while the last consider the whole soil area, including the sheared but not mobilized area. Another factor was the effect of the straw cutting disc, which pre-shear the soil in front of the tool. In sandy soil experiment, observed values of soil disturbed area were lower than expected, overestimating the effect of fuzzy model, which was not a deficiency of the model.
34
Estep, Judith. "Development of a Technology Transfer Score for Evaluating Research Proposals| Case Study of Demand Response Technologies in the Pacific Northwest." Thesis, Portland State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10248715.
Full textAbstract:
Investment in Research and Development (R&D) is necessary for innovation, allowing an organization to maintain a competitive edge. The U.S. Federal Government invests billions of dollars, primarily in basic research technologies to help fill the pipeline for other organizations to take the technology into commercialization. However, it is not about just investing in innovation, it is about converting that research into application. A cursory review of the research proposal evaluation criteria suggests that there is little to no emphasis placed on the transfer of research results. This effort is motivated by a need to move research into application.
One segment that is facing technology challenges is the energy sector. Historically, the electric grid has been stable and predictable; therefore, there were no immediate drivers to innovate. However, an aging infrastructure, integration of renewable energy, and aggressive energy efficiency targets are motivating the need for research and to put promising results into application. Many technologies exist or are in development but the rate at which they are being adopted is slow.
The goal of this research is to develop a decision model that can be used to identify the technology transfer potential of a research proposal. An organization can use the model to select the proposals whose research outcomes are more likely to move into application. The model begins to close the chasm between research and application—otherwise known as the “valley of death”.
A comprehensive literature review was conducted to understand when the idea of technology application or transfer should begin. Next, the attributes that are necessary for successful technology transfer were identified. The emphasis of successful technology transfer occurs when there is a productive relationship between the researchers and the technology recipient. A hierarchical decision model, along with desirability curves, was used to understand the complexities of the researcher and recipient relationship, specific to technology transfer. In this research, the evaluation criteria of several research organizations were assessed to understand the extent to which the success attributes that were identified in literature were considered when reviewing research proposals. While some of the organizations included a few of the success attributes, none of the organizations considered all of the attributes. In addition, none of the organizations quantified the value of the success attributes.
The effectiveness of the model relies extensively on expert judgments to complete the model validation and quantification. Subject matter experts ranging from senior executives with extensive experience in technology transfer to principal research investigators from national labs, universities, utilities, and non-profit research organizations were used to ensure a comprehensive and cross-functional validation and quantification of the decision model.
The quantified model was validated using a case study involving demand response (DR) technology proposals in the Pacific Northwest. The DR technologies were selected based on their potential to solve some of the region’s most prevalent issues. In addition, several sensitivity scenarios were developed to test the model’s response to extreme case scenarios, impact of perturbations in expert responses, and if it can be applied to other than demand response technologies. In other words, is the model technology agnostic? In addition, the flexibility of the model to be used as a tool for communicating which success attributes in a research proposal are deficient and need strengthening and how improvements would increase the overall technology transfer score were assessed. The low scoring success attributes in the case study proposals (e.g. project meetings, etc.) were clearly identified as the areas to be improved for increasing the technology transfer score. As a communication tool, the model could help a research organization identify areas they could bolster to improve their overall technology transfer score. Similarly, the technology recipient could use the results to identify areas that need to be reinforced, as the research is ongoing.
The research objective is to develop a decision model resulting in a technology transfer score that can be used to assess the technology transfer potential of a research proposal. The technology transfer score can be used by an organization in the development of a research portfolio. An organization’s growth, in a highly competitive global market, hinges on superior R&D performance and the ability to apply the results. The energy sector is no different. While there is sufficient research being done to address the issues facing the utility industry, the rate at which technologies are adopted is lagging. The technology transfer score has the potential to increase the success of crossing the chasm to successful application by helping an organization make informed and deliberate decisions about their research portfolio.
35
Harper, Sharleen Anne. "Mathematical models for dispersal of aerosol droplets in an agricultural setting : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematics at Massey University, Albany, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/814.
Full textAbstract:
Agrichemical spray drift is an issue of concern for the orcharding industry. Shelterbelts surrounding orchard blocks can significantly reduce spray drift by intercepting droplets from the airflow. At present, there is little information available with which to predict drift deposits downwind, particularly in the case of a fully-sheltered orchard block. In this thesis, we develop a simple mathematical model for the transport of airborne drifting spray droplets, including the effects of droplet evaporation and interception by a shelterbelt. The object is for the model to capture the major features of the droplet transport, yet be simple enough to determine an analytic solution, so that the deposit on the ground may be easily calculated and the effect of parameter variations observed. We model the droplet transport using an advection-dispersion equation, with a trapping term added to represent the shelterbelt. In order to proceed analytically, we discretise the shelterbelt by dividing it into a three-dimensional array of blocks, with the trapping in each block concentrated to the point at its centre. First, we consider the more straightforward case where the droplets do not evaporate; solutions are presented in one, two and three dimensions, along with explicit expressions for the total amount trapped and the deposit on the ground. With evaporation, the model is more difficult to solve analytically, and the solutions obtained are nestled in integral equations which are evaluated numerically. In both cases, examples are presented to show the deposition profile on the ground downwind of the shelterbelt, and the corresponding reduction in deposit from the same scenario without the shelterbelt.
36
Bramucci, Marcelo. "Determinação e quantificação de fatores de influência sobre a produtividade de "Harvesters" na colheita de madeira." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-02052002-083723/.
Full textAbstract:
Somente o setor de papel e celulose brasileiro teve em 2000 um faturamento de US$ 7,5 bilhões, com o consumo de 14 milhões de m3 de madeira de eucalipto. As operações de colheita e transporte florestal chegam a ser responsáveis por 50% do custo final da madeira posto fábrica. Em diversos sistemas de colheita mecanizada, o "harvester" é a máquina base utilizada na derrubada de árvores e processamento da madeira. Trata-se de um equipamento de custo elevado e de alta tecnologia, justificandose estudos no sentido de possibilitar um planejamento mais preciso das operações e o melhor aproveitamento dos equipamentos em termos de horas produtivas. O presente trabalho teve como objetivo, a partir de dados obtidos junto a empresas que utilizam "harvesters" para colheita e processamento de madeira de eucalipto, analisar a forma de influência das diferentes variáveis técnicas sobre a produtividade ou capacidade de produção desses equipamentos, e desenvolver modelos matemáticos que permitissem a predição da produtividade esperada para um "harvester" em determinadas condições de trabalho. Para tanto, foram coletados dados referentes a mais de 4 milhões de m3 de madeira de eucalipto colhidos em primeira rotação e 200 mil horas de trabalho realizado por 69 "harvesters", totalizando mais de 14 mil linhas de dados, junto às empresas Duratex S.A., Votorantim Celulose e Papel, Cia. Suzano de Papel e Celulose e Aracruz Celulose S.A. A partir desses dados foram montadas duas planilhas, uma para colheita processamento sem descascamento da madeira, e outra para colheita com descascamento realizado pelo "harvester". O volume individual médio das árvores foi a variável que, isoladamente, melhor explicou a capacidade produtiva dos "harvesters", seguida do DAP médio, da altura média e do volume de madeira por hectare. Através de regressões lineares múltiplas foram obtidos modelos mais precisos para cada sistema de trabalho, com ou sem descascamento de madeira, com coeficientes de determinação superiores a 0,75.The Brazilian cellulose and paper industry has been total sales of US$ 7.5 billions on 2000, with consume of 14 millions of m3 of eucalypt wood. Logging and wood transportation are responsible for 50% of final cost of wood. On cut-to-length system, the harvester is the main machine used on felling and processing of wood. This is an equipment with high cost and technology, justifying studies to improve the planning and precision of operations for obtainment of the best use of machines, with low number of work hours. This work aimed, based on industry data bank, to analyze the kind of influence of different technical variables about the productivity of these equipments and obtain mathematic models to predict the expected productivity for a harvester on different work conditions. It was picked up data from Duratex S.A., Votorantim Cellulose and Paper, Cia. Suzano of Paper and Cellulose and Aracruz Celulose S.A. It was done two spreadsheets, one for harvesting and processing with no debarking, and other for processing with debarking done by harvester. This study analyzed data referent of more than 4 millions m3 of eucalypt wood harvested on first rotation and 200 thousand hours of work by 69 harvesters, totalizing more than 14 thousand of data lines. Average individual volume was the variable that, isolated, better explain harvester productivity; followed by mean DBH, mean height and volume of wood per hectare. More precise models were obtained for different work systems (i.e. with or without wood debarking) with determination coefficient higher than 0.75, by multiple linear regression.
37
Omrane, Fatma. "Human health risk assessment of occupational exposure to trace metallic elements mixtures in metalworking industries in the Sfax metropolis (Tunisia)." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0097/document.
Full textAbstract:
Les éléments trace métalliques (ETM) sont des polluants qui sont sources de préoccupations majeures à cause de leurs toxicités et de leurs propriétés cumulatives. Certains d’eux peuvent être cancérogènes. La métropole de Sfax, située au sud de la Tunisie, a été touchée par des rejets et émissions d’ETM depuis des décennies. Plusieurs études ont confirmé que la pollution métallique est principalement d’origine anthropique, liée en particulier aux activités industrielles. Cela présente un risque sur la santé des habitants, particulièrement pour ceux qui sont également exposés par leur métier dans des procédés industriels. L’objectif de cette étude est d’évaluer les risques sanitaires associés à l’exposition professionnelle dans les industries qui manipulent des ETM dans leurs processus de production, en suivant l’approche de l’évaluation des risques sanitaires. Dans ce but, cinq entreprises qui utilisent des métaux comme matière première pour produire une variété de produits métalliques, ont accepté d’adhérer à notre étude. Les métaux qui étaient explorés sont Al, Cr, Ni, Cu, Zn and Pb. Des modèles mathématiques de prédiction des expositions professionnelles aux agents chimiques ont été utilisés pour estimer les concentrations des ETM dans l’air intérieur pour 15 postes différents. Des prélèvements atmosphériques ont été effectués afin de comparer les concentrations prédites à celles mesurées, en utilisant des prélèvements individuels ou sur postes fixes. Finalement, des prélèvements urinaires ont été collectés chez 61 travailleurs afin d’évaluer le lien entre l’excrétion des ETM et les niveaux atmosphériques. Globalement, les estimations des concentrations atmosphériques avaient une bonne concordance avec les valeurs mesurées sur l’ensemble des postes de travail. Des meilleures prédictions ont été trouvées pour certaines activités, en particulier pour des processus de découpage des tôles et de soudures. Les valeurs qui correspondent au 90ème percentile de la distribution de l’exposition ont été utilisées pour le calcul du « interaction-based hazard index HIint » pour évaluer les risques associés aux mélanges d’ETM. Un excès de risque total de cancer a été aussi calculé. Les résultats ont montré des expositions élevées qui peuvent provoquer des pathologies respiratoires, avec un HIint allant jusqu’à 93,6. Les niveaux les plus élevés sont attribués à la soudure à l'arc à l'électrode enrobée et au débitage et cisaillage des tôles. Ces risques augmentent à cause de l’effet synergique qui existe entre Cr, Ni et Cu. Des risques élevés de cancer du poumon et du rein ont été encore démontrés (risque total vie entière de cancer pour les ouvriers exposés : 3.7×10-4). Ce travail montre que les modèles mathématiques peuvent prédire correctement les niveaux d’exposition des ETM dans l’air intérieur pour plusieurs processus de la métallurgie. Ce résultat est intéressant pour aider les différents acteurs pour piloter de manière efficiente les systèmes de surveillance et la réduction des expositions dans ce secteur économique. Des progrès en matière d’hygiène industrielle sont nécessaires dans ce secteur industriel pour minimiser le risque sanitaire élevé auquel sont actuellement exposés les travailleurs concernésTrace metallic elements (TMEs) are pollutants of great concern even in trace amounts because of their toxicity and cumulative property. Some of them can be carcinogenic. The Sfax metropolis, located in the southern region of Tunisia, has been affected by releases of TMEs for decades. Several studies confirmed that this pollution is predominantly originated from anthropogenic sources, mainly from industrial activities. It represents a threat to the health of residents, particularly for those also exposed during occupational activities in industrial processes. The present study aims to assess health risks associated with occupational exposure in industries handling TMEs in their production processes, following the human health risk assessment approach. To this end, five companies using raw material containing TMEs to produce a variety of metallic products accepted to participate to the study. The metals that were investigated are Al, Cr, Ni, Cu, Zn and Pb. Mathematical models for estimating occupational exposure to chemicals were used to predict indoor air TME exposure levels in 15 different job tasks. Air monitoring was conducted in order to compare the predicted workplace air concentrations versus the direct measured ones, using both workplace-fixed monitors and personal samplers. And finally, urine samples were collected from 61 workers to assess whether TMEs excretion correlate with job exposure levels. Globally, the predicted air estimates relate well with measured concentrations over the whole set of job tasks. Better predictions were found for certain activities, in particular for steel cutting and welding processes. The values that correspond to the 90th percentile of the exposure distribution were then used in the interaction-based hazard index HIint to assess health risks associated with the mixtures of TMEs. Total cancer risk was also investigated. Results showed high exposures for metals that may elicit respiratory conditions, with a HIint reaching 93.6, the highest levels being for the shielded metal arc welding and metal shearing and slitting tasks. The risk is enhanced by a synergetic effect between Cr, Ni and Cu. High risks of lung and kidney cancers were demonstrated (the predicted life-long total cancer risk for exposed workers is 3.7×10-4). This work shows that mathematical models can be accurate in predicting TME airborne exposure levels for several processes in the metallurgic industry, a result that is of interest to help the different stakeholders to monitor efficiently exposure surveillance and abatement. Progress in industrial hygiene is needed in this industrial sector to reduce the high level of health risks currently experienced by the metalworking workers
38
Turcanu, Catrinel. "Multi-criteria decision aiding model for the evaluation of agricultural countermeasures after an accidental release of radionuclides to the environment." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210642.
Full textAbstract:
Multi-criteria decision aid has emerged from the operational research field as the answer given to a couple of important questions encountered in complex decisions problems. Firstly, as decision aiding tools, such methods do not replace the decision maker with a mathematical model, but support him to construct his solution by describing and evaluating his options. Secondly, instead of using a unique criterion capturing all aspects of the problem, in the multi-criteria decision aid methods one seeks to build multiple criteria, representing several points of view. This work explores the application of multi-criteria decision aid methods for optimising food chain countermeasure strategies after a radioactive release to the environment.
The core of the thesis is dedicated to formulating general lines for the development of a multi-criteria decision aid model. This includes the definition of potential actions, construction of evaluation criteria and preference modelling and is essentially based on the results of a stakeholders’ process. The work is centred on the management of contaminated milk in order to provide a concrete focus and because of its importance as an ingestion pathway in short term after an accident.
Among other issues, the public acceptance of milk countermeasures as a key evaluation criterion is analysed in detail. A comparison of acceptance based on stochastic dominance is proposed and, based on that, a countermeasures’ acceptance ranking is deduced.
In order to assess “global preferences” taking into account all the evaluation criteria, an ordinal method is chosen. This method allows expressing the relative importance of criteria in a qualitative way instead of using, for instance, numerical weights. Some algorithms that can be used for robustness analysis are also proposed. This type of analysis is an alternative to sensitivity analysis in what concerns data uncertainty and imprecision and seeks to determine how and if a model result or conclusion obtained for a specific instance of a model’s parameters holds over the entire domain of acceptable values for these parameters.
The integrated multi-criteria decision aid approach proposed makes use of outranking and interactive methodologies and is implemented and tested through a number of case studies and prototype tools.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
39
FARIAS, Lourival Antonio Simões de. "Estudo da viabilidade de agroindustrialização do coco (cocos nucifera L.) em São Gonçalo, Sousa-PB." Universidade Federal de Campina Grande, 2015. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/787.
Full textAbstract:
Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-23T14:52:55Z
No. of bitstreams: 1
LOURIVAL ANTONIO SIMÕES DE FARIAS - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 10079550 bytes, checksum: 58af2a33af68f236c4e05efeb4f7ee04 (MD5)Made available in DSpace on 2018-05-23T14:52:55Z (GMT). No. of bitstreams: 1 LOURIVAL ANTONIO SIMÕES DE FARIAS - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 10079550 bytes, checksum: 58af2a33af68f236c4e05efeb4f7ee04 (MD5) Previous issue date: 2015-03
O semiárido brasileiro é caracterizado por chuvas irregulares, alta evapotranspiração, elevadas temperaturas e baixa pluviometria, fenômenos que assolam grande parte do território brasileiro, sendo visualizado com maior intensidade na região Nordeste. Dentro deste espaço, localiza-se o estado da Paraíba, que periodicamente vivencia o fenômeno da seca, a qual é causadora das irregularidades de safras agrícolas e prejuízos nas lavouras. Buscou-se, neste estudo, demonstrar a influência da variação de temperatura e da sazonalidade pluviométrica, nos polos receptores do fruto, Rio de Janeiro e São Paulo, na formação do preço unitário deste, independentemente das variações de temperatura e das chuvas na região de São Gonçalo, o que faz oscilar o seu valor unitário, deixando o produtor sem possibilidades de negociação ou mesmo de um maior lucro em relação à demanda e à oferta. Nesta dissertação tem-se por objetivo verificar as possibilidades de aproveitamento dos derivados do coco, em substituição à venda do fruto verde in natura, desenvolvendo em um primeiro momento, a análise de um questionário sobre as características socioeconômicas deste produtor, de sua propriedade e da relação com os atravessadores na produção e venda do fruto in natura. Utilizando-se os dados coletados, realizou-se o confronto entre os índices pluviométricos e de temperatura média mensal, tanto do polo produtor, como do polo receptor, com o preço unitário do coco verde em São Gonçalo no período de 2012 a 2014. Na sequência, foram utilizadas ferramentas matemáticas de modelagem e de custo, para observar quais as possibilidades de agroindustrialização dos derivados do coco, analisando os seus custos e as suas devidas restrições, buscando uma situação máxima de receita que possibilite ao produtor armazenar, beneficiar, agregar valor e até mesmo agroindustrializar os derivados do coco a exemplo de: água, leite, óleo, fibra, ralados, etc. Verificou-se que existem alternativas mais lucrativas, para o produtor, ao realizar a agroindustrialização dos derivados do fruto, principalmente na produção do óleo de coco.
The Brazilian semiarid region is characterized by irregular rainfall, high evapotranspiration, high temperatures and low rainfall, phenomena that plague much of the Brazilian territory, being viewed with greater intensity in the Northeast. Within this space is located the state of Paraiba, which periodically experiences the phenomenon of drought, which is the cause of the irregularities of agricultural crops and damage to crops. We sought in this study demonstrate the influence of changes in temperature and rainfall seasonality in recipient poles of fruit, Rio de Janeiro and São Paulo, in the pricing of this unit, regardless of temperature variations and rainfall in the region of São Gonçalo, which makes oscillate the unit value, leaving the producer without tradability or even a higher profit in relation to demand and supply. In this dissertation has for objective to verify the possibilities of use of derivatives coconut, replacing the sale of the green fruit fresh, developing in the first place, the analysis of a questionnaire on the socioeconomic characteristics of this producer, its property and relationship with the middlemen in the production and sale of fresh fruit. Using the data collected, there was the confrontation between the rainfall and average temperatures of both the production hub, and the recipient pole, with the unit price of coconut in São Gonçalo in the 2012 period to 2014. In sequence, mathematical modeling tools and cost were used to observe which industrialization possibilities of coconut derivatives, analyzing their costs and their due restrictions, seeking a maximum state revenue that enables the producer storing, processing, adding value and even agroindustrializar derived from coconut example: water, milk, oil, fiber, grating, etc. It was found that more profitable alternative for the producer to perform the industrialization of the derivatives of fruit, especially in the production of coconut oil.
40
Kong, Gary S. "Social disclosure by Australian listed mineral mining companies: A stakeholder approach." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 1996. https://ro.ecu.edu.au/theses/971.
Full textAbstract:
This study examines the incentives of Australian listed mineral mining companies within the stakeholder theoretical framework to disclose socially responsible information in their corporate annual report. The three dimensions of the stakeholder theory were empirically tested to explain the association of a social disclosure model comprising categories of social disclosure for environment, energy, product and services, human resources and community involvement, with nine firm-specific characteristics. The sample of 179 Australian listed mineral mining companies for the financial year ending 1994 was obtained by personal contact. The extent of social disclosure was measured by a dichotomous index against the social disclosure model. Results of multivariate tests provide evidence that Membership of the Australian Mining Industry Council (Stakeholder Power dimension), and company size (a Control Variable) which was jointly represented by three surrogates (total assets, total sales, and market capitalisation), to be the most significant variables associated with the social disclosure model. The presence of a social responsibility group (Strategic Posture dimension) was also significantly related to the extent of total disclosure and four categories of social disclosure (environment, product and services, human resources, and community involvement). Company age (a Control Variable) was significantly associated with energy related disclosure. Commercial production (a Control Variable) was significant to the total disclosure and two categories of social disclosure (environment, and human resources). Return on equity, and systematic risk (Economic Performance dimension) did not explain social disclosure. The research findings imply that economic performance measures derived from the financial statements of corporate annual reports do not seem to be reliable surrogates for evaluating voluntary social disclosure. To improve the extent of disclosure of socially responsible information, accounting regulators may need to consider issuing an accounting standard on corporate social responsibility disclosure.
41
Franzosi, Lígia de Oliveira. "Modelo de referência para processo de exportação de produtos alimentícios para União Europeia." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2509.
Full textAbstract:
Muitos estudos ressaltam a importância do crescimento do comércio mundial para incentivo no avanço econômico das nações e como motivador da globalização. A exportação é uma das melhores formas de uma empresa alavancar seu crescimento, sendo que um dos setores que mais se destaca nas exportações é o da agroindústria. Entretanto, as empresas que exportam com mais facilidade são as de grande porte, pois tem suporte e conhecimento dos procedimentos envolvidos. As empresas de pequeno porte apresentam dificuldades em função do alto custo envolvido, da falta de capacitação e domínio dos procedimentos envolvidos, em especial quando enfrentam países exigentes, os quais são os potenciais compradores. Os países da União Europeia estão entre os maiores importadores de produtos alimentícios do Brasil, porém, são os que possuem as maiores exigências na importação de produtos. Sendo assim, o objetivo deste trabalho é desenvolver um modelo de referência que considere as exigências técnicas e normativas da União Europeia para auxiliar a pequena indústria no processo de exportação de alimentos. Para isso é apresentada uma revisão bibliográfica sobre internacionalização das empresas, exigências do processo de exportação e dificuldades encontradas durante o processo de exportação. Em seguida, uma pesquisa de campo é apresentada, visando identificar as dificuldades encontradas pelas indústrias de alimentos durante o processo de exportaçã. Também são analisados alguns dos principais modelos existentes para suportar o processo de exportação, os quais são analisados e comparados, visando obter as melhores práticas de cada um deles, em função das exigências europeia. Com a coleta previamente realizada, elabora-se um modelo para suportar um processo completo de exportação, desde o atendimento às exigências nacionais, até às exigências internacionais em vários âmbitos. O modelo é submetido a avaliação de seu conceito por meio de especialistas que oferecem sugestões de melhorias para que o modelo apresente melhor desempenho em campo industrial.Many studies highlight the importance of growth in world trade for encouraging the economic advancement of nations as a globalization motivator. Export is one of the best ways for a company to leverage its growth, and one of the sectors that most stands out in exports is the agrobusiness. However, companies that export more easily are the large ones, it has support and knowledge of the procedures involved. The small companies have difficulties due to the high cost involved, the lack of training and mastery of the procedures involved, particularly when faced with demanding countries, which are potential buyers. The European Union countries are among the largest importers of food products from Brazil, however, it is those with the highest demands on import products. Therefore the objective of this study is to develop a reference model that considers the technical and regulatory requirements in Europe to help small industry in food export process. For this is presented a review of internationalization of companies, requirements of the export process and difficulties encountered during the export process. Then, a field research is presented in order to identify the difficulties found by the food industry during the export process. It also examines some of the main existing models to support the export process, which are analyzed and compared in order to obtain the best practices of each of them, according to the European requirements. With the collection previously held, draws up a model to support a complete export process, from compliance with national requirements, to the international requirements in various areas. The model is subjected to evaluation of their concept by experts who offer suggestions for improvements to the model presents better performance in the industrial field.
42
Almeida, Paulo Nazareno Alves. "Fontes de crescimento e sistema produtivo da orizicultura no Mato Grosso." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/11/11132/tde-24052004-142414/.
Full textAbstract:
O presente trabalho tem como objetivo descrever o sistema produtivo e quantificar as fontes de crescimento da orizicultura no Mato Grosso, em competição com a cotonicultura, a milhocultura e a sojicultura, no período de 1980 a 2001. Nota-se grandes avanços tecnológicos empregados na cultura do arroz sob o sistema terras altas, diminuindo a diferença produtiva entre este e o arroz irrigado. Diante destas alterações e da carência de informações no tocante ao cultivo de terras altas, são necessários estudos que demonstrem essas alterações de forma sistematizada. Utilizou-se a metodologia shift-share na mensuração das fontes de crescimento das atividades agrícolas, tendo como fatores explicativos da evolução da produção os efeitos área, rendimento, composição da produção e localização geográfica. As alterações na área cultivada das culturas foram quantificadas pelos efeitos escala e substituição, realizadas na análise individual por cultura. Com enfoque no arroz, as demais culturas estudadas foram o algodão, o milho e a soja, escolhidas por competirem em maior grau com o arroz na ocupação da área agrícola. Apesar das pastagens apresentarem grande relação com a orizicultura, estas não foram incluídas no estudo, devido à ausência de informações referentes à área e ao rendimento para as microrregiões em todo o período. Verificou-se que o arroz de terras altas continua carregando o estigma de abertura de área para domesticação da terra e posterior substituição pela cultura da soja ou pastagens. A orizicultura tem seu uso também relacionado à recuperação de pastagens e rotação com soja. As culturas do algodão e do milho pouco se relacionam diretamente com o arroz, ao contrário da soja e das pastagens. Constataram-se alguns entraves ao desenvolvimento da orizicultura no estado, como a oferta insuficiente de sementes, problemas de mistura varietal na principal variedade cultivada no estado, assim como a falta de estrutura de secagem e armazenagem própria dos produtores, ocasionando dificuldades na comercialização. Todas as culturas analisadas tiveram crescimento da produção de 1980 a 2001. A cultura do arroz apresentou crescimento da produção à taxa de 2,4% a.a., devido aos efeitos rendimento e localização geográfica, enquanto o efeito área foi negativo à taxa de 0,99% a.a.. A cultura do arroz foi a única a ceder área agrícola para as demais culturas (208.003 ha), na década de 1980. Os efeitos composição da produção (4,56% a.a.) e área (4,04% a.a.) foram os mais importantes na explicação do crescimento do valor da produção das culturas no estado no período de 1980 a 2000; os efeitos rendimento e localização geográfica também foram positivos. Esses resultados indicam que o crescimento do valor da produção decorre de uma alteração na composição das culturas, ao se substituir ou aumentar a área plantada com culturas mais rentáveis, e decorre também da incorporação de novas áreas, verificada na década de 1990. A elevação do rendimento (3,83% a.a.) indica o aumento da produtividade das culturas e o efeito localização geográfica (0,72% a.a.) denota a mudança de cultivo para regiões que apresentam melhores condições de cultivo, como solo e condições climáticas.The current study aims to describe the rice production system and to quantify its sources of growth in the state of Mato Grosso, while competing with cotton, corn and soybean crops, between 1980 and 2001. Great technological advances have been observed in upland rice growing, reducing productive differences between the upland and the irrigated rice. In face of these changes and the lack of information regarding the upland rice, studies showing these alterations in a systematized way are required. The shift-share approach was used to measure the sources of growth of agricultural activities, having as determining factors of production increase the area, yield, crop combination and geographical location effects. Changes in the cultivated area were quantified by the scale and substitution effects, in the individual analysis by culture. Cotton, corn, soybean and rice were the cultures studied, with emphasis to the last one. They were chosen due to the large degree of competition with rice in the utilization of the agricultural area. Despite the strong relation between rice and pastures, they were not included in this study. It is due to the lack of information regarding the area and the yield of pastures in those micro-regions, during the analyzed period. It was observed that the upland rice still has a stigma of opening up rural areas, for domestication of land and following substitution by soybean plantation or pasture. Rice growing is also related to pasture recovery and soybean rotation. Its relation with corn and cotton growing, in turn, is not as direct. Some obstacles to the development of rice cultivation in the state of Mato Grosso were detected. As examples: the insufficient supply of seeds; varietal mixture problems in the major variety cultivated in the state; the lack of drying and storage structures for the growers, which hampers commercialization. All of the cultures analyzed registered an increase of production from 1980 to 2001. Rice production grew at an annual average rate of 2.4%, due to yield and geographical location effects, while the area effect was negative by 0.99% per year. Rice was the only culture that transferred agricultural area to the others (208,003 ha) in the eighties. The crop combination (4.56% per year) and the area (4.04% per year) effects were the most important effects in the explanation of production value growth of these crops, from 1980 to 2000, in Mato Grosso. Yield and geographical location effects were also positives. These results indicate that the production value growth derives from an alteration in crops combination when the plantation is substituted or the area cultivated with a more profitable culture is expanded. It derives, as well, from the aggregation of new areas, as observed in the nineties. The increase of yield (3.83% per year) indicates the growth of these crops productiveness. The geographical location effect (0.72% per year) denotes a move of the cultivation to regions that present better growing conditions, as soil and weather conditions.
43
Paiva, Yhasmin Gabriel. "Estimativa do índice de área foliar por métodos óticos e sensoriamento remoto para calibrar modelo ecofisiológico em plantios de eucalipto em áreas de relevo ondulado." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/5282.
Full textAbstract:
Made available in DSpace on 2015-03-26T13:50:18Z (GMT). No. of bitstreams: 1
texto completo.pdf: 1742312 bytes, checksum: dc42985c8c2356eecb3f0d6b67cfccab (MD5)
Previous issue date: 2009-07-24Conselho Nacional de Desenvolvimento Científico e Tecnológico
The purpose of this study was to estimate the leaf area index (LAI) in eucalyptus forest plantations, using optical instruments and satellite imagery to evaluate the response to the physical and climatic conditions of the study area, and based on these data, calibrate and simulate yields with an ecophysiological growth model. The study was conducted in four eucalyptus stands of two ages in the following two regions: Cocais, at a higher altitude and Rio Doce, at a lower altitude, in the Rio Doce basin, in eastern Minas Gerais. Nine plots were marked in each stand, according to the exposure of the relief surface. The experimental data were collected in August 2008 (dry season) and January 2009 (rainy season). The LAI was estimated by measures of the plant area index (PAI) by the equipment LAI-2000 (LI-COR) and hemispherical photographs. The expression PAI was adopted since these sensors do not measure only the leaf element. The method of destructive analysis was used to check the accuracy of the LAI estimates. Meteorological data were collected at two monitoring stations installed near the stands in each region of the study. The model 3PG (Physiological Principles in Predicting Growth) was run using the parameterization established in previous studies for the same regions. The 3PG was calibrated with vegetation indices (VIs) of the sensor Moderate Resolution Imaging Spectroradiometer (MODIS). The model simulation was performed based on the corrected global radiation according to the slope and exposure of the relief surface. It was found that the PAI derived from LAI2000 was the indirect method that correlated best with the observed LAI. Eucalyptus responded to climatic seasonality, with lower LAI values in the dry than in the rainy season. The LAI,in the stands at higher altitudes (Cocais) exceeded that of the lower plots (Rio Doce), probably due to the higher evapotranspiration demand in the Rio Doce basin. The incidence of solar radiation on the northern slope surfaces was higher, in agreement with the correction performed for inclined surfaces. On this face, again, higher LAI values were measured in the field and estimated by the model 3PG well as for other estimated variables that express the crop productivity. The results for the inclined areas were not conclusive. Studies should investigate whether the response pattern is repeated in analyses of the influence of the latitude of the site. The estimates of the model 3PG calibrated by the normalized difference vegetation index (NDVI) agreed well with the observed data and temporal data verified by MODIS-VI.
Este trabalho teve por objetivo estimar o índice de área foliar (IAF) em plantios florestais de eucalipto, utilizando instrumentos óticos e imagens de satélite para se avaliar a resposta frente às condições físico-climáticas presentes na área de estudo e, a partir destes dados, calibrar e simular a produtividade por meio de um modelo ecofisiológico de crescimento. O estudo foi realizado em quatro talhões de plantios de eucalipto em duas diferentes idades presentes em duas regiões: Cocais, de maior altitude e Rio Doce, mais baixa, localizadas na bacia do Rio Doce, leste de Minas Gerais. Foram alocadas nove parcelas em cada talhão, considerando as faces de exposição do relevo. Os dados experimentais foram coletados em agosto de 2008 (período seco) e janeiro de 2009 (período chuvoso). Realizaram-se as estimativas do IAF por meio de medidas de índice de área de planta (IAP) pelos equipamentos LAI- 2000 (LI-COR) e câmera com lentes hemisféricas. Adotou-se a expressão IAP visto que esses sensores não discernem unicamente o elemento foliar em suas medidas. Para verificar a exatidão das estimativas do IAF foi utilizado o método da análise destrutiva. Os dados meteorológicos foram adquiridos por meio de duas estações automáticas instaladas próximas às áreas dos talhões em cada região do estudo. Executou-se o modelo 3PG (Physiological Principles in Predicting Growth) com parametrização realizada em trabalhos anteriores para as mesmas regiões. Foi realizada a calibração do 3PG com índices de vegetação (IV s) do sensor Moderate Resolution Imaging Spectroradiometer (MODIS). A simulação do modelo foi realizada a partir da radiação global corrigida segundo a inclinação e a face de exposição do terreno. Verificou-se que o IAP obtido com LAI2000 foi o método indireto melhor correlacionado com o IAF observado. O eucalipto respondeu à sazonalidade climática, apresentando menores valores de IAF na época seca em relação à estação chuvosa. O rendimento dos talhões localizados nas maiores altitudes (Cocais) superou os talhões das altitudes mais baixas (Rio Doce) em IAF, provavelmente devido à maior demanda evapotranspirativa presente em Rio Doce. As faces de exposição norte apresentaram maior incidência de radiação solar de acordo com a correção realizada para superfícies inclinadas. Nesta face, também, foram verificados maiores valores de IAF medidos a campo e estimados pelo modelo 3PG bem como para outras variáveis estimadas que expressam a produtividade do plantio. Os resultados para as áreas de relevo inclinado não são conclusivos, devendo ser realizados estudos para verificar se o padrão de resposta obtido se repete analisando a influência da latitude do local. O modelo 3PG calibrado pelo NDVI apresentou boas estimativas pontuais com os dados observados e temporais verificada pelos dados IV s-MODIS.
44
Kean, J. M. "Metapopulation theory in practice." Lincoln University, 1999. http://hdl.handle.net/10182/1372.
Full textAbstract:
A metapopulation is defined as a set of potential local populations among which dispersal may occur. Metapopulation theory has grown rapidly in recent years, but much has focused on the mathematical properties of metapopulations rather than their relevance to real systems. Indeed, barring some notable exceptions, metapopulation theory remains largely untested in the field. This thesis investigates the importance of metapopulation structure in the ‘real world’, firstly by building additional realism into metapopulation models, and secondly through a 3-year field study of a real metapopulation system. The modelling analyses include discrete-and continuous-time models, and cover single species, host-parasitoid, and disease-host systems, with and without stochasticity. In all cases, metapopulation structure enhanced species persistence in time, and often allowed long-term continuance of otherwise non-persistent interactions. Spatial heterogeneity and patterning was evident whenever local populations were stochastic or deterministically unstable in isolation. In metapopulations, the latter case often gave rise to self-organising spatial patterns. These were composed of spiral wave fronts (or ‘arcs of infection’ in disease models) of different sizes, and were related to the stability characteristics of local populations as well as the dispersal rates. There was no evidence for self-organising spatial patterns in the host-parasitoid system studied in the field (the weevil Sitona discoideus and its braconid parasitoid Microctonus aethiopoides), and a new model for the interaction suggested that this is probably due to the strong host density-dependence and stabilising parasitism acting on local populations. Dispersal may be important because of very high mortality in dispersing weevils, which may be related to the scarcity of their host plant in the landscape. If this is the case, the model suggested that local weevil density may be sensitive to the area of crop grown. Stochastic models showed that species in suitably large metapopulations may persist for very long times at relatively low overall density and with very low incidence of density-dependence. This suggests that metapopulation processes may explain a general inability to detect density-dependence in many real populations, and may also play an important part in the persistence of rare species. For host-parasitoid metapopulation models, persistence often depended on the way in which they were initialised. Initial conditions corresponding to a biological control release were the least likely to persist, and the maximum host suppression observed in this case was 84%, as compared with 60% for the corresponding non-spatial models and >90% often observed in the field. Metapopulation structure also allowed persistence of ‘boom-bust’ disease models, although the dynamics of these were particularly dependent on assumptions about what happens to disease classes at very low densities. Models assuming infinitely divisible units of density, models incorporating a non-zero extinction threshold, and individual-based models all gave differing results in terms of disease persistence and rate of spatial spread. Fitting models to overall metapopulation dynamics often gave misleading results in terms of underlying local dynamics, emphasising the need to sample real populations at an appropriate scale when seeking to understand their behaviour.
45
Creti, Christian. "Fermentation méthanique et désulfuration de gaz par voie bactérienne : proposition d'un bioréacteur de désulfuration, optimisation des deux opérations du procédé." Paris 6, 1986. http://www.theses.fr/1986PA066309.
Full textAbstract:
Conception et réalisation d'un pilote de laboratoire de 20 litres, garni de supports bactériens en PVC, en vue de produire du biogaz (avec des teneurs en H2s au moins égales à 0,3%. ) Emploi de déchets agro-alimentaires riches en sulfates. L'automatisation est réalisée en connectant des capteurs et des actionneurs à un ordinateur industriel. Le biogaz produit passe en continu et en ligne dans un bioréacteur de désulfuration en molécules organiques. Proposition d'un modèle intégrant les différentes vitesses de réaction. Perspectives de synthèse de molécules à haute valeur ajoutée.
46
Dissart, Jean-Christophe. "The economics of erosion and sustainable practices : the case of the Saint-Esprit watershed." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0006/MQ44158.pdf.
Full text
47
Santos, José Altair Ribeiro dos. "Proposta de modelo inteligente de definição de produto para atendimento à diretiva RoHS." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1379.
Full textAbstract:
As empresas de manufatura necessitam integrar seus processos internos digitalmente para se tornarem mais competitivas e entregarem produtos com maior qualidade ao mercado consumidor. Informações definidas nas primeiras etapas de projeto precisam ser recuperadas em todas as fases do ciclo de vida de um produto. Para alcançar este objetivo são necessários modelos de informação que incorporem inteligência e permitam a representação do mundo real. Por outro lado, fabricantes de produtos eletroeletrônicos precisam cumprir requisitos ambientais presentes em marcos regulatórios, como a Diretiva RoHS, para poderem vender seus equipamentos em diversos países. O presente trabalho propõe a aplicação de modelos semânticos para ajudar as empresas a cumprir os requisitos estabelecidos pela Diretiva RoHS. O modelo, criado usando uma ontologia de referência, estabelece relações semânticas entre entidades que representam fases do ciclo de vida do produto, estruturas de produtos e objetos de negócios. Processos de negócio modelados permitem identificar fluxos de informação, bem como atividades que estão ligadas aos requisitos RoHS, percebidas por meio da geração de relatórios disponíveis no framework denominado Projeto Essential. O modelo semântico resultante é, portanto, útil para converter as necessidades relacionadas com o meio ambiente, endereçando requisitos através de um processo de desenvolvimento de produtos que aborda a diretiva RoHS. Um produto eletroeletrônico fabricado por indústrias nacionais foi selecionado para demonstrar a viabilidade da solução proposta.Manufacturing companies need to integrate their internal processes digitally to become more competitive and deliver higher quality products to the consumer market. Information defined at early design stages needs to be recovered at all stages of the life cycle of a product. To accomplish this, information models that incorporate intelligence and enable the representation of the real world are necessary. On the other hand, electronic products manufacturers need to comply with environmental requirements present in regulatory frameworks as the RoHS Directive in order to offer their products in several countries. The present work proposes the application of semantic models for helping companies meet the requirements established by the RoHS Directive. A model, created using a reference ontology, establishes semantic relationships between entities that represent product lifecycle stages, product structure and business objects. Business processes, modeled in the form of activity and information flows, are linked to RoHS requirements that can be viewed through the reports in the Essential Project open source framework. The resulting semantic model is, therefore, useful for converting environment-related needs to design requirements through a product development process that addresses the RoHS Directive. A consumer electronics product has been selected for demonstrating the feasibility of the proposed solution.
48
Malmgren, Henrik. "Revision of an artificial neural network enabling industrial sorting." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392690.
Full textAbstract:
Convolutional artificial neural networks can be applied for image-based object classification to inform automated actions, such as handling of objects on a production line. The present thesis describes theoretical background for creating a classifier and explores the effects of introducing a set of relatively recent techniques to an existing ensemble of classifiers in use for an industrial sorting system.The findings indicate that it's important to use spatial variety dropout regularization for high resolution image inputs, and use an optimizer configuration with good convergence properties. The findings also demonstrate examples of ensemble classifiers being effectively consolidated into unified models using the distillation technique. An analogue arrangement with optimization against multiple output targets, incorporating additional information, showed accuracy gains comparable to ensembling. For use of the classifier on test data with statistics different than those of the dataset, results indicate that augmentation of the input data during classifier creation helps performance, but would, in the current case, likely need to be guided by information about the distribution shift to have sufficiently positive impact to enable a practical application. I suggest, for future development, updated architectures, automated hyperparameter search and leveraging the bountiful unlabeled data potentially available from production lines.
49
David, Hélène. "Etude de matrices polymères permettant la libération contrôlée d'agents actifs en agriculture : expérimentation et modélisation des transferts de matière." Saint-Etienne, 1989. http://www.theses.fr/1989STET4004.
Full textAbstract:
L'agent actif considéré a été l'éthoprophos, principe nématicide utilisé en agrochimie, mais dans un premier temps, l'aniline a été utilisé comme agent simulant. Les processus d'absorption et de désorption dans l'eau, ont été modélisés, dans le cas d'un granulé composé d'EVA pur, à l'aide d'une solution analytique de l'équation de Fick. Un modèle mathématique basé sur une méthode numérique a été construit pour décrire les transferts à travers un granulé composé par un noyau et une enveloppe
50
O'Mara, Laurence Paul. "Linkages from the farm sector to the Australian macroeconomy : towards a theoretical and empirical analysis." Phd thesis, 1985. http://hdl.handle.net/1885/122769.
Full textAbstract:
The volatile fortunes of the Australian farm sector in recent
years, and particularly the severe drought of 1982-83, has renewed
interest, amongst policy makers and policy advisers, in the impact
which developments in the farm sector may have on the macroeconomy.
However, in the Australian literature, there are few detailed
theoretical or empirical analyses of farm/macro linkages. Further,
the existing Australian macroeconomic models do not provide a fully
suitable framework for undertaking such an analysis.
In view of these gaps or inadequacies in the existing
literature, the objective of the present thesis is, firstly, to make
a contribution towards the development of a macroeconomic model
framework which is suitable for analysing the role of the farm
sector in the Australian macroeconomy and, secondly, to undertake
some of the associated analysis.
To that end, a relatively large theoretical model is developed
in which the linkages between the farm sector and the macroeconomy
are emphasised. The model proves to be too large and complex to be
tractable using strictly formal algebraic techniques. Therefore, in
the first instance, the analysis is undertaken using a slightly less
rigorous geometric characterisation of the model. After this
geometric approach is fully exploited, some parts of the analysis
are extended and refined using theoretical simulation techniques.
A number of important results are established in these
theoretical analyses. It is shown that, in principle, the marketing
and institutional environment in which the farm sector operates is
of major importance in influencing the macroeconomic implications of
production and price shocks originating in the farm sector. It is
also demonstrated that shocks to the volume of farm production or to
farm prices may influence macroeconomic variables such as non-farm
G.D.P., the interest rate and the state of the balance of payments
in a direction which is at variance to that suggested by intuition
or conventional wisdom. For example, an exogenous (drought induced)
decline in farm production could have a beneficial impact on
non-farm output and the state of the balance of payments.
Alternatively, a drought which has a (more intuitive) adverse effect
on the overall level of economic activity may place upward pressure
on the interest rate. In a similar vein, an exogenous increase in
the price of farm commodities on overseas markets may reduce
domestic economic activity and worsen the balance of payments.
Because of the time and resources required to develop and use a
relatively large theoretical simulation model, it is not feasible,
within the context of the thesis, to apply theoretical simulation
techniques to each of the analyses which are undertaken less
formally using the geometric characterisation of the model.
However, the foundations are laid to permit the ready extension of
the theoretical simulation technique to these remaining cases as
part of a future research exercise. The existence of the
theoretical simulation model and analyses should also facilitate the
eventual development of an empirical version of the model. Given that some further post thesis research will be required
in order to develop an empirical version of the full model
structure, it was decided to seek some tentative and preliminary
empirical results from a very simple empirical version of the
model. A major conclusion to emerge from this empirical analysis is
that the farm sector may not have declined in relative importance as
a source of change in non~farm output over the period since the
early 1950s and may even have increased in importance. Such a
result serves to provide some additional motivation for persisting
with the line of research commenced in the thesis.