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The Impact of Prohexadione-calcium on Grape Vegetative and Reproductive Development and Wine ChemistryLo Giudice, Danielle 23 May 2002 (has links)
Prohexadione-calcium (P-ca), as ApogeeTM, was evaluated in 2000 and 2001 for impact to grape vegetative and reproductive development. In 2000, P-ca (250 mg/L) was applied to Seyval, Cabernet Sauvignon, and Cabernet franc (125, 250, and 375 mg/L). P-ca reduced primary shoot growth for all cultivars and decreased cane pruning weight of Seyval. P-ca (375 mg/L) increased Cabernet franc canopy gaps but increased Cabernet Sauvignon lateral leaf area and leaf layer number. P-ca reduced components of yield for all cultivars. In 2001, P-ca (250 mg/L) was applied singularly at weekly intervals to Cabernet Sauvignon clusters and pre and post-bloom to Cabernet franc and Chardonnay canopies. Application at E-L stages 21 and 23 decreased Cabernet Sauvignon fruit set whereas application at E-L stages 26, 27, and 29 reduced berry weight without impacting fruit set. Berry weight reduction correlated to higher color intensity (420+520 nm), anthocyanins, total phenols and phenol-free glycosyl-glucose (PFGG). Cabernet franc vegetative and reproductive development was generally not affected yet treatment increased absorbance at 280, 420, and 520 nm, color intensity, anthocyanins and total phenols. Pre-bloom applications inhibited Chardonnay vegetative development, and reduced components of yield, and fruit chemistry values: hydroxycinnamates, total phenols, flavonoids, PPFG and absorbance at 280 and 320 nm. Post-bloom applications did not affect Chardonnay vegetative or reproductive development, yet increased PFGG. Treatment did not affect Chardonnay wine chemistry but two post-bloom applications increased Cabernet franc wine anthocyanins and total phenols. Wine aroma and flavor triangle difference tests did not indicate significant treatment differences. / Master of Science
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Bat swarming as an inspiration for multi-agent systems: predation success, active sensing, and collision avoidanceLin, Yuan 22 February 2016 (has links)
Many species of bats primarily use echolocation, a type of active sensing wherein bats emit ultrasonic pulses and listen to echoes, for guidance and navigation. Swarms of such bats are a unique type of multi-agent systems that feature bats's echolocation and flight behaviors. In the work of this dissertation, we used bat swarming as an inspiration for multi-agent systems to study various topics which include predation success, active sensing, and collision avoidance. To investigate the predation success, we modeled a group of bats hunting a number of collectively behaving prey. The modeling results demonstrated the benefit of localized grouping of prey in avoiding predation by bats. In the topics regarding active sensing and collision avoidance, we studied individual behavior in swarms as bats could potentially benefit from information sharing while suffering from frequency jamming, i.e., bats having difficulty in distinguishing between self and peers's information. We conducted field experiments in a cave and found that individual bat increased biosonar output as swarm size increased. The experimental finding indicated that individual bat acquired more sensory information in larger swarms even though there could be frequency jamming risk. In a simulation wherein we modeled bats flying through a tunnel, we showed the increasing collision risk in larger swarms for bats either sharing information or flying independently. Thus, we hypothesized that individual bat increased pulse emissions for more sensory information for collision avoidance while possibly taking advantage of information sharing and coping with frequency jamming during swarming. / Ph. D.
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Size reduction characteristics of an experimental swing hammermillKesterson, James Walter January 1939 (has links)
Size-reduction of materials is an important operation in many chemical industries. The purpose of size-reduction are: (a) for specific mesh size product; (b) grinding for release, or unlocking grinding for purposes of surface exposure or locked-in products for chemical or physical attack; (c) specific surface grinding for product; and (d) size modulus, where limited mesh size is needed for specific processing operation.
Size-reduction is accomplished by (a) impact, (b) differential movement of adjacent surfaces and (c) by the combination of both. Most size-reduction of a combination of both, whereas swing hammermill grinding is due mainly to impact.
Rittingers’ and Kicks’ laws are empirical formulas which do not make an attempt to resolve the forces as applied to grinding into their component parts. Possibly the application of the component forces as applied to impact grinding would give a key to the multiple factors controlling size-reduction. If this can be worked out, the general formula might be obtained that would apply to all phases of size-reduction.
The purpose of this investigation is to study the factors as applied to swing hammermill grinding; also, to determine if it is possible to formulate an equation which will hold for the size reduction of various materials. / Master of Science
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Strategies for Improving Reproductive Efficiency of Beef Cattle with Assisted Reproductive TechnologiesTimlin, Claire 12 June 2020 (has links)
Reproductive efficiency in beef cattle can be improved with reproductive technologies at the herd, individual cow, and embryonic levels. Decreasing the bull:cow ratio for natural service after fixed time artificial insemination (FTAI) can alleviate economic burden associated with FTAI. In experiment 1, the total number of cows exposed per bull was negatively correlated with pregnancy rate to natural service on first return to estrus after FTAI in fall herds. The number of open cows per bull in fall herds using one natural service sire was negatively correlated with pregnancy rate on first return to estrus. There was no correlation between number of cows exposed per bull and pregnancy rates in fall herds with multiple sires or in spring herds. However, bull:cow ratio accounted for only 5–11% of the variation in pregnancy rates, thus we conclude that a reduced bull:cow ratio did not affect natural service return to estrus pregnancy rate. Experiment 2 examined how supplementing calcium salts of soybean oil (CSSO) improves beef cow fertility. Non-pregnant cows received supplement with either saturated fat or omega-6 rich CSSO. There were no changes in dominant follicle diameter, corpus luteum volume, plasma progesterone, or endometrial gene expression (PTGES and AK1B1, PPARA, PPARA, PPARD) between treatments. Plasma and follicular fluid fatty acid compositions were altered between treatments. Experiment 3 examined if size parameters of zygotes have potential as a non-invasive, objective embryo selection method. The outer diameter, area of ooplasm, and thickness of zona pellucida (ZP) was digitally measured on individual artificially activated oocytes and in-vitro fertilized (IVF) zygotes. Larger outer diameter increased probability of development to the blastocyst stage by days 7 and 8 for activated oocytes and tended to by day 8 for IVF zygotes. Thinner ZP increased probability of development to blastocyst stage on days 7 and 8 for oocytes, and to day 8 for IVF zygotes. Area did not affect development but was positively correlated with blastomere number on day 8. An interaction between diameter and ZP thickness was observed in zygotes, but not activated oocytes, suggesting oocyte activation is not always a suitable replacement for in-vitro fertilization. / Doctor of Philosophy / We need to improve reproductive efficiency in beef cows if we are to combat the challenges of producing more food while using less resources due to limited land availability and concerns with greenhouse gas emissions from agriculture. In cow-calf production systems, this means producing one healthy calf per cow per year. Cattlemen can implement a variety of assisted reproductive technologies to achieve this goal. Achieving maximal reproductive efficiency will require using technologies that are incorporated into herd management, individual animal care, and in vitro embryo production.
Fixed time artificial insemination (FTAI) allows cattlemen to maximize the number of cows becoming pregnant and calving earlier in the season to increase efficiency. Unfortunately, use of FTAI is uncommon in cow-calf production systems because of labor and economic restraints. In order to improve economic feasibility of FTAI, bull-related costs need to be reduced, which can be done through increasing the number of cows serviced per bull (decreasing the bull:cow ratio). This study retrospectively examined correlations between the bull:cow ratio and pregnancy rate on first return to estrus after FTAI. There was little to no correlations between bull:cow ratio and pregnancy rates, and if they were significant, there was much variation in the data. With this we concluded that a reduced bull:cow ratio does not affect pregnancy rate on first return to estrus, allowing producers to increase the number of cows serviced by a single bull and reduce bull related costs.
Supplementing calcium salts of soybean oil (CSSO) that are rich in omega-6 fatty acids can enhance beef cow fertility, but it is unclear why this happens. Using non-pregnant cows as a model, we studied the effects of either saturated fat or CSSO on reproductive parameters such as ovarian structures, hormone concentrations, and uterine gene expression. There were no changes in any of these parameters between treatments, but there were changes in the concentrations of certain plasma and follicular fluid fatty acids. There was also reduced activity of lipid metabolism enzymes. We were unable to pinpoint how CSSO supplementation improves reproduction, but the altered fatty acid content of tissues and altered enzyme activity likely plays a key role, thus ultimately impacting fatty acid utilization and growth of the embryo.
In-vitro embryo production can increase the number of offspring produced from a single female and accelerate the incorporation of animals with high genetic merit into herds. To obtain optimal pregnancy rates with in vitro embryos, we should develop non-invasive, objective methods for identifying the most viable embryos. This study examined if size parameters of activated and fertilized oocytes are indicative of successful development. We discovered that oocytes with large diameters and those with thin zona pellucida were most likely to develop to the blastocyst stage, and that the area of the cell was positively correlated with blastocyst total cell number. An interaction between diameter and ZP thickness was observed in zygotes, but not activated oocytes, suggesting oocyte activation is not always a suitable replacement for in-vitro fertilization. This suggests that digital measurements of fertilized oocytes may have potential as objective selection criteria.
Addressing issues of reproductive inefficiency in beef cows requires a comprehensive approach, as there is not one ideal solution. Management techniques can alleviate the cost of FTAI by reducing the number of bulls used without affecting pregnancy rates. Supplementing CSSO can alter tissue fatty acids to enhance fertility. Finally, the efficiency of in vitro embryo production can be improved by selecting better embryos for transfer without compromising the embryo. Combinations of all these techniques can create more reproductively efficient animals.
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Mechanistic Understanding of the NOB Suppression by Free Ammonia Inhibition in Continuous Flow Aerobic Granulation BioreactorsKent, Timothy Robert 15 February 2019 (has links)
A partial nitritation-anammox continuous flow reactor (CFR) was operated for eight months demonstrating that a mixture of large anammox-supported aerobic granules (ASAGs) and small conventional aerobic granules (CAGs) can be maintained stably for extended periods of time. The influent NH4+ was kept at 50 - 60 mg N L-1 to verify that the upper range of total ammonia nitrogen (TAN) for domestic wastewater can supply an inhibitory level of free ammonia (FA) for nitrite oxidizing bacteria (NOB) suppression in CFRs at pH around 7.8. The ammonia oxidizing bacteria (AOB):NOB activity ratio was determined for a series of granule sizes to understand the impact of mass diffusion limitation on the FA inhibition of NOB. When dissolved oxygen (DO) limitation is the only mechanism for NOB suppression, the AOB:NOB ratio was usually found in previous studies to increase with the granule size. However, the trend is reversed when FA has an inhibitory effect on NOB, as was observed in this study. The decrease in AOB:NOB ratio indicates that the resistance to the diffusion of FA along the granule radius limited its ability to inhibit NOB. This means smaller granules, e.g. diameter < 150 microns, are preferred for nitrite accumulation when high FA is present, e.g. in the partial nitritation-anammox process. The trend was further verified by observing the increase in the apparent inhibition coefficient, KI,FAapp, as granule size increased. This study for the first time quantified the effect of diffusion limitation on the KI,FAapp of NOB in granules and biofilms. A mathematical model was then utilized to interpret the observed suppression of NOB. The model predicted that NOB suppression was only complete at the granule surface. The NOB that did survive in larger granules was forced to dwell within the granule interior, where the FA concentration was lower than that in the bulk solution. This means FA inhibition can be taken advantage of as an effective means for NOB suppression in small granules and thin biofilms. Further, FA and DO were found to be both required for the stratification of AOB and NOB in partial nitritation-anammox CFRs. The structural stratification commonly observed in granules is then concluded to be a consequence but not a cause of the NOB suppression. / MS / A partial nitritation-anammox continuous flow reactor (CFR) was operated for eight months demonstrating that granular sludge can be maintained stably for extended periods of time. In this approach, NH3 is only partially converted to NO2 - (partial nitritation), and the conversion to NO3 - is prevented by the suppression of nitrite oxidizing bacteria (NOB). NH3 and NO2 - are then utilized by anammox bacteria to create N2 gas. The influent NH4 + fed to the reactor was kept at 50 to 60 mg N L-1 to verify that the upper range of total ammonia nitrogen (TAN) for domestic wastewater can supply a sufficiently high level of free ammonia (FA) to inhibit NOB growth in CFRs at a pH around 7.8. It is expected that the penetration of a substrate into granule sludge will experience diffusional resistance as it moves from water to denser solid material and is consumed by bacteria. The ammonia oxidizing bacteria (AOB):NOB activity ratio was determined for a series of granule sizes to understand the impact of mass diffusion limitation on the FA inhibition of NOB. When dissolved oxygen (DO) limitation is the only mechanism for NOB suppression, the AOB:NOB ratio was usually found in previous studies to increase with the granule size. However, the trend is reversed when FA has an inhibitory effect on NOB, as was observed in this study. The decrease in AOB:NOB ratio indicates that the resistance to the diffusion of FA, which increases with increasing granule size, along the granule radius limited its ability to inhibit NOB. This means smaller granules, e.g. diameter < 150 µm, are preferred for NO2 - accumulation when high FA is present. The trend was further verified by observing the increase in the apparent inhibition coefficient, KI,FAapp, as granule size increased. This coefficient quantifies the effectiveness of an inhibitor, with larger values indicating weaker inhibition. This study for the first time quantified the effect of diffusion limitation on the KI,FAapp of NOB in granules and biofilms. A mathematical model was then utilized to interpret the observed suppression of NOB. The model predicted that NOB suppression was only complete at the granule surface. The NOB that did survive in larger granules was forced to dwell within the granule interior, where the FA concentration was lower than that in the bulk solution. This means FA inhibition can be taken advantage of as an effective means for NOB suppression in small granules and thin biofilms. Further, FA and DO were found to be both required for the stratification of a layer of AOB at the surface over a layer of NOB in partial nitritation-anammox CFRs. The structural stratification commonly observed in granules is then concluded to be a consequence but not a cause of the NOB suppression.
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Simultaneous Lot sizing and Lead-time Setting (SLLS)Via Queuing Theory and Heuristic searchMuthuvelu, Sethumadhavan 23 January 2004 (has links)
Materials requirements planning (MRP) is a widely used method for production planning and scheduling. Planned lead-time (PLT) and lot size are two of the input parameters for MRP systems, which determine planned order release dates. Presently, planned lead-time and lot size are estimated using independent methodologies. No existing PLT estimation methods consider factors such as machine breakdown, scrap-rate, etc. Moreover, they do not consider the capacity of a shop, which changes dynamically, because the available capacity at any given time is determined by the loading of the shop at that time. The absence of such factors in calculations leads to a huge lead-time difference between the actual lead-time and PLT, i.e., lead-time error. Altering the size of a lot will have an effect not only on the lead-time of that lot but also on that of other lots. The estimation of lot size and lead-time using independent methodologies currently does not completely capture the inter-dependent nature of lead-time and lot size.
In this research, a lot-sizing model is modified in such a way that it minimizes the combination of setup cost, holding cost and work-in-process cost. This proposed approach embeds an optimization routine, which is based on dynamic programming on a manufacturing system model, which is based on open queuing network theory. Then, it optimizes lot size by using realistic estimates of WIP and the lead-time of different lots simultaneously for single-product, single-level bills of material. Experiments are conducted to compare the performance of the production plans generated by applying both conventional and the proposed methods. The results show that the proposed method has great potential and it can save up to 38% of total cost and minimize lead-time error up to 72%. / Master of Science
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Effects of Transplant Season and Container Size on Landscape Establishment of Kalmia latifolia L.Hanson, Anne-Marie 14 May 2002 (has links)
Mountain laurel (Kalmia latifolia L.) is relatively difficult to establish in landscapes. One experiment tested the effect of container size on the water relations of pinebark substrate embedded in field soil. Two other experiments tested the effects of transplant season and container size on landscape establishment of nursery-produced mountain laurel. Experiment one compared volumetric water content of embedded substrate of five sizes (4-L to 100-L) to adjacent field soil at two depths with time domain reflectometry (TDR) during a dry down cycle. Available water was calculated by subtracting unavailable water (estimated with pressure plates) from volumetric water content (TDR measurements). Adjacent soil contained more available water than embedded substrate. The middle depth held more water than the top. Larger pinebark substrate volumes retained higher volumetric water content than smaller volumes. The second experiment consisted of 7.6- and 19-L containers of Kalmia latifolia L. ‘Olympic Wedding’, transplanted into field soil in October or May. Larger container plants generally had lower xylem potential than smaller plants, but better visual ratings. Root growth into surrounding soil was negligible for all treatments. Leaf area was higher for spring transplants than fall transplants. Experiment three was a rhizotron study with 19-L plants, transplanted in October or May. Canopy growth of spring transplants was greater than fall transplants, but fall transplants had longer roots into the backfill. Overall, our data suggest that fall transplanting will potentially allow faster plant establishment than spring transplanting. The effect of container size on plant establishment could not be determined. / Master of Science
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Object size determines the spatial spread of visual timeFulcher, Corinne, McGraw, Paul V., Roach, N.W., Whitaker, David J., Heron, James 27 July 2016 (has links)
Yes / A key question for temporal processing research is how the nervous system
extracts event duration, despite a notable lack of neural structures dedicated
to duration encoding. This is in stark contrast with the orderly arrangement
of neurons tasked with spatial processing. In this study, we examine the linkage
between the spatial and temporal domains. We use sensory adaptation
techniques to generate after-effects where perceived duration is either compressed
or expanded in the opposite direction to the adapting stimulus’
duration. Our results indicate that these after-effects are broadly tuned,
extending over an area approximately five times the size of the stimulus.
This region is directly related to the size of the adapting stimulus—the
larger the adapting stimulus the greater the spatial spread of the aftereffect.
We construct a simple model to test predictions based on overlapping
adapted versus non-adapted neuronal populations and show that our effects
cannot be explained by any single, fixed-scale neural filtering. Rather, our
effects are best explained by a self-scaled mechanism underpinned by
duration selective neurons that also pool spatial information across earlier
stages of visual processing. / J.H. is supported by the Vision Research Trust (43069). N.W.R. is supported by a Wellcome Trust Research Career Development Fellowship (WT097387).
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Analysis Using Size Exclusion Chromatography of poly(N-isopropyl acrylamide) using Methanol as an EluentSwift, Thomas, Hoskins, Richard, Telford, Richard, Plenderleith, R.A., Pownall, David, Rimmer, Stephen 25 May 2017 (has links)
Yes / Size Exclusion Chromatography is traditionally carried out in either aqueous or non-polar solvents. A system to present molar mass distributions of polymers using methanol as a mobile phase is presented. This is shown to be a suitable system for determining the molar mass distributions poly(N-isopropylacrylamide)s (PNIPAM); a polymer class that is often difficult to analyze by size exclusion chromatography. DOSY NMR was used to provide intrinsic viscosity data that was used in conjunction with a viscometric detector to provide absolute calibration. Then the utility of the system was shown by providing the absolute molar mass distributions of dispersed highly branched PNIPAM with biologically functional end groups. / Wellcome Trust
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Powder Processing and Characterization of W-3Ni-1Fe Tungsten Heavy AlloyHiser, Matthew A. 11 May 2011 (has links)
Mechanical alloying, compaction by cold isostatic pressing, and pressureless sintering were used to study the potential for W â 3 wt% Ni â 1 wt% Fe to be processed into the bulk nanocrystalline form as a replacement material for depleted uranium in kinetic energy penetrators. Milling time and sintering temperature were varied from 15 to 100 hours and 1000 to 1300°C respectively. Particle size analysis and SEM showed a bimodal particle size distribution with most of the particles below 10 µm in size. XRD peak broadening analysis showed crystallite size to be reduced to below 50 nm, while peak shifting indicated a reduction in W lattice parameter due to dissolution of Ni and Fe atoms into the W BCC lattice.
Post-sintering bulk characterization showed density increasing strongly with increasing sintering temperature to above 90% of theoretical density at 1200°C. Apparent activation energy for sintering decreased strongly with increasing milling time. SEM micrographs showed a bimodal grain size distribution with some areas of smaller submicron grains and others with larger grains on the order of 1 – 4 µm, likely connected to the bimodal particle size distribution from milling. XRD and SEM also showed the precipitation of two secondary phases during sintering: (Fe, Ni)6W6C incorporating carbon from the grinding media and an FCC solid solution of Ni, Fe, and W. The intermetallic carbide phase will increase strength but reduce ductility of the bulk material, which is not desirable. Micro and macrohardness testing show similar trends as density with a strong correlation with sintering temperature. / Master of Science
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