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1
Gil, Tae Kyung. "The kinetics of liquid lithium reaction with various atmospheres." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15068.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE
Bibliography: leaves 143-144.
by Tae Kyung Gil.
M.S.
2
Rhein, Willy. "A study of neutral and charged polonium-216 in various atmospheres." Thesis, University of Greenwich, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338349.
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Yuzbasi, Nur Sena. "Pyrolysis And Combustion Behaviour Of Various Fuels In Oxygen-enriched Air And Co2 Atmospheres." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612944/index.pdf.
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Oxy-fuel combustion technology, which is based on burning coal in a mixture of oxygen and recycled flue gas (RFG), is suggested as one of new promising technologies for capturing CO2 from power plants.
In this thesis study, the pyrolysis and combustion behaviour of various fuels including imported coal, petroleum coke, two different types of indigenous lignites, olive residue and their blends with different proportions in air and oxy-fuel conditions were investigated by using non-isothermal thermogravimetric method (TGA) coupled with Fourier-transform infrared (FTIR) spectrometer.
Pyrolysis tests were carried out in nitrogen and carbon dioxide environments, which are the main diluting gases of air and oxy-fuel environment, respectively. Pyrolysis results reveal that weight loss profiles are similar up to high temperature zone in both pyrolysis environments, indicating that CO2 behaves as an inert gas in this temperature range. However, further weight loss takes place in CO2 atmosphere
v
after 700oC due to CO2-char gasification reaction which is observed in pyrolysis of all fuel samples.
Combustion experiments were carried out in four different atmospheresair, oxygen-enriched air environment (30 % O2 &ndash
70 % N2), oxy-fuel environment (21 % O2 &ndash
79 % CO2) and oxygen-enriched oxy-fuel environment (30 % O2 &ndash
70 % CO2). Combustion experiments show that replacing nitrogen in the gas mixture by the same concentration of CO2 does not affect the combustion process significantly but leads to slight delay (lower weight loss rate and higher burnout temperature) in combustion. Overall comparison of weight loss profiles shows that higher oxygen content in the combustion environment is the dominant factor affecting the combustion rather than the diluting gas. As O2 concentration increases profiles shift through lower temperature zone, peak and burnout temperatures decrease, weight loss rate increases and complete combustion is achieved at lower temperatures and shorter times. Pyrolysis and combustion behaviour of three different fuel blends were also investigated. Results reveal synergistic interactions in combustion tests of all blends in all combustion environments. During pyrolysis and combustion tests gaseous products CO2, CO, H2O, CH4, SO2 and COS were identified in flue gas and analyzed by using FTIR. Results indicate that higher CO and COS formation take place during pyrolysis tests due to gasification reaction in CO2 atmosphere at high temperature zone. Gaseous species evolution trends in combustion tests are found specific for each fuel. However, evolution trends slightly shift to lower temperatures in oxygen-enriched conditions.
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Wilson, Shawn. "Oxidation of Manganese-Containing Aluminium Alloys : Oxidation of Molten Mn-Containing Al Alloys in Various Atmospheres." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22707.
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An oxidation study was performed on 99.99% Al, Al1%Mn and Al5%Mn materials, both ina thermogravimetric furnace, and in a muffle furnace. The mass gain behaviour for thesematerials was studied and compared for dierent temperatures and surface preparations,and was compared to previous work on Al1Mn.Curve fitting was used with the thermogravimetric data in an attempt to develop a math-ematical model to describe oxidation in the Al1%Mn materials, but a satisfactory modelcould not be found.The oxidized materials were then analyzed in the Scanning Electron Microscope usingEDS and Auger microprobe analysis, both for chemical composition and to analyze thestructure of the oxide that was formed.The main findings from the thermogravimetric work are as follows:1. Error analysis showed that the mass measurement errors were at least two orders ofmagnitude smaller than the mass measurements, so any dierences between sampleswas due to dierent oxidation behaviour in the sample.2. There was inconsistent oxidation behaviour for the Al1Mn surface-cleaned TGAsamples; for six identical samples and experiments, ve samples showed comparableresults, while one sample showed much larger mass gain.3. Sample preparation has a large inuence on oxidation behaviour in the mue fur-nace.4. Mn content has an inuence on oxidation behavior; there was a trend of increasingoxidation with increasing Mn content in the mue furnace samples.The main ndings from the SEM analysis of the oxidized 99.99% Al, Al1%Mn andAl5%Mn materials are as follows:1. The oxides formed on the Al1Mn and Al5Mn materials were thicker and dierentthan those found on 99.99% Al2. The oxides formed on the Al1Mn and Al5Mn materials did not contain Mn oxides3. The oxides formed on the Al1Mn and Al5Mn materials had small particles of Mnmetal completely surrounded by Al2O34. Mn-rich particles were found in the interior of the Al1Mn and Al5Mn samples5. Small clusters of Mn metal were found among the Al2O3 particles on the surface ofthe Al1Mn and Al5Mn samplesGlow Discharge Optical Emission Spectroscopy showed that there was no measurable Mnon the surface of an as-extruded Al1Mn strip, and the Mn was decient to a depth ofsome 100nm from the surface. A similar Al1Mn extruded strip that had 50m of thesurface mechanically removed also did not contain Mn on the surface, and had a similarMn prole to the as-extruded strip.A qualitative physical model of oxidation was suggested, based on thermogravimetricdata.
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Choucha, Sam E. "Color and shelf-life studies of fresh beef packaged in various gas atmospheres and stored at refrigerated temperature." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0024/MQ37108.pdf.
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Al-Zenki, Sameer F. "The combined effect of MAP and other barriers on the growth of Salmonella enteritidis in packaged chicken thighs under various storage conditions /." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27269.
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Salmonella enteritidis has recently emerged as a potential pathogen in poultry products. The growth of S. enteritidis in poultry is affected by several factors such as storage temperature, pH, water activity, modified atmosphere and the presence of preservatives. All of these factors may act alone or in combination with each other resulting in a synergistic, antimicrobial effect.In this research, initial storage studies were done to determine the effect of various atmospheres (air, vacuum, oxygen absorbent and gas packaging) on the microbial changes of packaged chicken thighs followed by challenge studies with a strain of S. enteritidis$ sp{ rm{NAST}}$. Chicken thighs were packaged in Cryovac bags and stored at 4 and 12$ sp circ$C for up to 28d. Changes in headspace gas composition, pH, drip loss, color and odor were monitored at each sampling day.
The effect of various packaging treatments, dipping solutions (chitosan (0.2%w/v) and potassium sorbate (0.2%w/v)) and low dose irradiation (1.5 & 3.0 kGy) on the growth of S. enteritidis$ sp{ rm NAST}$ and on the shelf-life of chicken thighs stored at 4 and 12$ sp circ$C was also investigated. (Abstract shortened by UMI.)
7
Tang, Yi. "Atmospheric fate of various fluorocarbons." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/10598.
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Mathieu, Manon. "Gazéification autotherme de biomasse en lit fixe co-courant pour la production de syngaz sans azote." Electronic Thesis or Diss., Ecole nationale des Mines d'Albi-Carmaux, 2024. http://www.theses.fr/2024EMAC0012.
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Pour répondre aux enjeux de la transition énergétique, il est communément admis qu'il est nécessaire de changer notre façon de produire de l'énergie. Parmi les sources renouvelables, la biomasse est la plus prometteuse de part sa grande disponibilité partout dans le monde, ainsi que ses usages multiples (production de chaleur, de biogaz et de bioproduits). La gazéification de biomasse est une voie de valorisation thermochimique qui permet de convertir les biomasses non fermentescibles en un gaz de synthèse appelé syngaz. Ce syngaz est majoritairement composé d'hydrogène, de monoxyde de carbone, de méthane, de dioxyde de carbone et d'eau. De nombreux gisements de biomasse sont de taille restreinte. Pour les valoriser, il est important de développer des technologies de petite échelle (production <1MW) qui restent énergétiquement intéressantes. Le procédé de gazéification à lit fixe autotherme est la technologie la plus pertinente pour répondre à ce besoin. En effet, l'autothermicité garantit le déroulement des réactions chimiques sans apport d'énergie extérieur. Pour assurer cette autothermicité, il est nécessaire d'apporter de l'oxygène dans le réacteur via l'agent gazéifiant. L'air est l'agent de gazéification principalement utilisé à ce jour. L'azote de l'air utilisé, inerte dans le procédé, devient alors l'espèce majoritaire du syngaz produit. Ceci rend la valorisation du syngaz en biocarburant particulièrement difficile. Pour pallier ce problème tout en conservant l'autothermicité, l'utilisation de nouveaux agents de gazéification peut être envisagée : mélange vapeur d'eau - oxygène, dioxyde de carbone - oxygène, air enrichi (> 21 %vol d'oxygène). Le but de cette thèse est d'anticiper les changements induits par l'utilisation de nouvelles atmosphères sur le procédé de gazéification de biomasse en lit-fixe co-courant. Pour cela, une étude numérique a été menée à l'aide de modèles thermodynamique et cinétique. Nous avons voulu comprendre plus en détail certains phénomènes du processus de gazéification à lit fixe co-courant. L'impact de l'atmosphère sur la vitesse de pyrolyse oxydante, avec ces nouvelles atmosphères, a été étudié expérimentalement par des études thermogravimétriques à l'échelle de la particule. Une seconde étude expérimentale s'est focalisée sur l'évolution de la taille de particules lors de leur gazéification en lit fixe co-courant et leur influence sur la perte de charge du lit dans le réacteur. Celle-ci permet en effet de piloter correctement le procédé et rend compte de son efficacitéIt is well known that changing the way to produce energy is mandatory to meet the energetic transition needs. Among the renewable resources, biomass is the more promising thanks to its availability all around the world and its various uses (heat, biogas or bioproducts production). Biomass gasification is a thermochemical way to transform drought biomass into synthesis gas called syngas. Syngas is mainly composed of hydrogen, carbon monoxide, methane, carbon dioxide and water. Most of biomass deposits are small-size. To valorise them, small-scale technologies (< 1MW) must be developed. Autothermal downdraft fixed-bed gasification fits the best to meet this need. Indeed, autothermal behaviour enables kinetic reactions to take place without external sources of energy. Autothermal behaviour is ensured by feeding oxygen into the reactor via the gasifying agent. Nowadays, the most commonly used gasifying agent is air. Inert nitrogen from air then becomes the more abundant compound of the syngas. This makes syngas valorisation into biofuels particularly challenging. To fix this issue while keeping the autothermal behaviour, the use of new gasifying agents is considered: mixture of O2-H2O, mixture of O2-CO2 or enriched air (> 21 %vol O2). The aim of this thesis is to investigate and anticipate the changes induced by using these new atmospheres on the biomass downdraft gasification process. To reach this goal, a numerical study based on equilibrium and kinetic models has been led. More specific phenomena of the downdraft gasification process have also been investigated. Impact of these new atmospheres on the oxidative pyrolysis kinetic of a particle has been studied. It has been carried out thanks to a macro-thermogravimetric device. Another experimental study focused on the particles size evolution during downdraft gasification process and how they influence pressure drops though the bed in the reactor. Pressure drops enables to drive the process and is a relevant indicator of the process efficiency
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Jeong, Yu Seon, Atri Bhattacharya, Rikard Enberg, C. S. Kim, Mary Hall Reno, Ina Sarcevic, and Anna Stasto. "Prompt atmospheric neutrino flux from the various QCD models." E D P SCIENCES, 2017. http://hdl.handle.net/10150/625070.
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We evaluate the prompt atmospheric neutrino flux using the different QCD models for heavy quark production including the b quark contribution. We include the nuclear correction and find it reduces the fluxes by 10% - 50% according to the models. Our heavy quark results are compared with experimental data from RHIC, LHC and LHCb.
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Koo, Ja-Ho. "The patterns of polar near-surface ozone associated with various atmospheric conditions." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53418.
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Understanding the spatiotemporal pattern of near-surface ozone is the key part of polar atmospheric environment. The near-surface ozone can be depleted by the catalytic bromine chemistry in the heterogeneous phase but produced due to the snow photochemistry of nitrogen. In addition to the local chemistry, ozone pattern is also affected by regional meteorology and air-mass transport. Since the polar region is quite sensitive to the climate change, these conditions can be also affected by climate change and variability. Based on the analysis of large amount of dataset combined with in-situ observations, satellite measurements, model simulations, and global reanalysis data, the characteristics of polar ozone pattern and relation to the regional and large-scale atmospheric situations were investigated.
At first, the characteristics of tropospheric ozone depletion events (ODEs) in the Arctic spring (April 2008) with satellite measured BrO and backtrajectories. Analysis of these data shows that the ODEs are due to either local halogen chemistry or short-range transport from adjacent high-BrO regions. Sometimes local ozone loss is surprisingly deep, particularly the unstable boundary layer at Churchill seems contribute to free-tropospheric BrO. Continually the influences of large-scale atmospheric patterns to the polar surface ozone are investigated. In years with frequent ODEs at Barrow and Alert, the WP teleconnection pattern is usually in its negative phase, during which the Pacific jet is strengthened but the storm track from western Pacific is weakened. Both factors tend to reduce the transport of ozone-rich airmass from mid-latitudes to the Arctic, creating a favorable environment for the Arctic ODEs. Comparison between Barrow and Alert shows the initiation of ODEs in spring is decided by the solar intensity and the termination is by the surface air temperature. Monthly frequency of ODEs also indicate the wind strength from the Arctic Ocean is largely influential to ODEs. The surface ozone at South Pole reveals year-round reversal trends during 3 decades, which is consistent with what lower-tropospheric temperature shows. Their strong correlation implies the possibility of large meridional mixing in warm conditions, which enhances the background level of ozone and nitrogen at South Pole.
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Straccione, Nicholas C. "Coral Recruitment to Various Artificial Substrata, Miami Beach, FL." NSUWorks, 2002. http://nsuworks.nova.edu/occ_stuetd/98.
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The City of Miami has placed 12 artificial reefs approximately 100m offshore in two parallel transects. The reason for this deployment was to tum a barren seabed into a productive environment for aquatic organisms. The reefs were placed close to the shoreline to allow easy access for snorkellers, divers, and fisherman. Three different types of reef materials were used in constructing the artificial reefs: boulders composed of limestone, concrete shaped as tetrahedrons, and concrete mixed with tire aggregate shaped as tetrahedrons. This study consisted of two separate assessments: I) a survey from two of each of the different reef types that were assessed bimonthly for one year to observe coral recruitment and 2) a survey of all 12 artificial reefs once at the end of the study to observe coral recruitment. In the year-long study, the results indicated that the number of coral recruits were highest on the boulder reefs (0.05>p>0.025, n=2), a significant difference. However, there was no significant difference in the area of corals on each substrata (0.10>p>0.05, n=2). In the final assessment of all 12 artificial reefs the greatest number of corals and area of corals on average were on the boulder reefs. However, there was no significant difference in either the number of coral recruits (0.50>p>0.25, n=4) or coral area (0.25>p>0.10, n=4). An explanation for this non-significance was the low coral recruitment of boulder reef two (B2). When B2 was treated as an outlier there was significance in both the number and the area of corals (0.025>p>0.01, n=3).
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Fussman, Chris R. "High energy laser propagation in various atmospheric conditions utilizing a new, accelerated scaling code." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42628.
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Approved for public release; distribution is unlimitedFor this thesis, an atmospheric propagation code named ANCHOR (Atmospheric NPS Code for High Energy Laser Optical pRopagation) was developed and utilized to study the propagation of high energy lasers in various atmospheric conditions and for numerous laser configurations. The ANCHOR code accesses existing industry databases to obtain relevant optical properties for various atmospheres and then uses scaling laws to simulate laser propagation through the defined environments. ANCHOR accounts for the effects of atmospheric diffraction, turbulence, platform jitter and thermal blooming on the laser beam, and outputs on-target irradiance and power-in-the-bucket profiles for a wide range of laser wavelengths. Several known physical trends associated with laser propagation will be reproduced, and the results will be compared to the industry accepted propagation code Wavetrain. The results of ANCHOR studies will indicate that the 100 kW-class high energy laser can effectively engage slow-moving targets at ranges greater than five kilometers in clear weather by delivering enough energy to melt 0.1 liters of one millimeter-thick aluminum aircraft skin in five seconds. For hazy, turbulent, and rainy conditions, the laser can effectively engage targets from ranges closer than three kilometers, but reasonable dwell times are only achieved for ranges closer than two kilometers.
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Davis, Neil Nathaniel. "Dynamic and Stochastic Modeling of Various Components of the Hydrological Cycle for East Africa." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-05032007-094125/.
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This research has investigated the ability to model precipitation over East Africa using the RegCM regional climate model, and the ability of a stochastic model to predict Lake Victoria lake level one season in advance. The stochastic model was built using precipitation, sea surface temperatures and temperature, and provides detail about the steps used to develop the model. Precipitation modeling was carried out using RegCM and several convective schemes were compared to determine which performed best for East Africa. Additionally the microphysical scheme SUBEX was investigated thoroughly and several tuning parameter changes were made. Finally the precipitation from RegCM was split into 9 rainfall classifications which were then studied to determine how the regional climate model performed for representing rainfall events in the model, in terms of duration, intensity, and overall structure between all the event types.
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Oxenyuk, Victoria. "Distribution Fits for Various Parameters in the Hurricane Model." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1366.
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The FPHLM is the only open public hurricane loss evaluation model available for assessment of hazard to insured residential property from hurricanes in Florida. The model consists of three independent components: the atmospheric science component, the vulnerability component and the actuarial component. The atmospheric component simulates thousands of storms, their wind speeds and their decay once on land on the basis of historical hurricane statistics defining wind risk for all residential zip codes in Florida.
The focus of the thesis was to analyze atmospheric science component of the Florida Public Hurricane Loss Model, replicate statistical procedures used to model various parameters of atmospheric science component and to validate the model. I establish the distribution for modeling annual hurricane occurrence, choose the best fitting distribution for the radius of maximum winds and compute the expression for the pressure profile parameter Holland B.
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Petrie, Christopher David. "Effectiveness of Chemical Inducers on Settling and Settlement of Scleractinian Coral Larvae on Various Substrates." NSUWorks, 2000. http://nsuworks.nova.edu/occ_stuetd/310.
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Sessile marine invertebrates often exhibit non-random distributions both horizontally and vertically. The larvae of scleractinian corals settle and metamorphose in response to numerous environmental stimuli including substrate composition and the presence of chemical signals, such as extracts of certain red crustose coralline algae. In this study, seven different substrates common to past research efforts were infused with an extract from the red crustose coralline alga, Hydrolithon boergesenii, and placed on the bottom of the ocean, as were similar plates containing no extract. Substrate plates were deployed during the months following the August 1999 coral-spawning event on a reef near Fort Lauderdale, Florida.
Larvae settled on plates placed on the shoreward side of the reef 2.12 times as often as plates placed on the seaward side of the reef. This difference was significant whether the plates contained algal extracts (p=0.004 by two-way ANOVA) or did not contain algal extracts (P = 0.003 by Two-way ANOVA). Reef location also influenced settling independent of plate composition. Peak settlement was observed on unglazed ceramic tiles on the shoreward side of the reef, while the lowest settlement was observed on glass plates on the shoreward side of the reef. Two-way ANOVA with replication showed significant differences in plate material (P = 0.031), presence or absence of algal extract (P = 0.002), and in the interaction of these variables (P = 0.009). Larvae settled on plates containing the algal extracts 2.60 times as often as plates without algal extract.
Multiple analysis of variance (MANOVA) for the interaction of all variables indicated significant interactions for extract presence (P = 0.002), reef zone location (P = 0.036), and plate material (P = .031). The interactions between algal extract presence and reef zone were also significant (P = 0.009), as were the interactions between plate material and algal extract presence (P = 0.009). Simultaneous MANOVA for all variables was not significant (P = 0.071), probably due to large variation in settling plate composition, variation in the concentration and activity of the algal extracts applied to the plates, as well as variation in the microhabitat across the reef.
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McMahon, David Z. "The Effects of Various Salinities on the Growth, Reproduction, and Pathology of Blue Tilapia (Oreochromis aureus)." NSUWorks, 1998. http://nsuworks.nova.edu/occ_stuetd/327.
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Blue tilapia, Oreochromis aureus were cultured from fingerling through maturation, in outdoor tanks, at varying salinities, for a period of nine months, from September 19, 1997 to June 19, 1998. Twelve tanks were used for testing four different salinities, with three replicates each. Each tank had a surface area of 0.8 m2, a water depth of 48cm, and held a volume of 350 liters. Each tank was stocked with ten O. aureus, with a total mean weight of 100 grams, and fed 5% to 10% body weight per day depending on size throughout the study. Salinity was the only induced variable throughout the experiment. Three tanks were the freshwater control group and salinity was held at 0 ppt. Salinities in three tanks were maintained at 10 ± 2ppt. Salinities in three tanks were maintained at 20 ± 2ppt and the salinities for the remaining three tanks were maintained at 30 ± 2ppt. Complete water changes were done each month, and the fish were individually weighed and an estimate of uneaten food was done. Any morphological or behavioral changes were noted for each fish, and each was regularly checked for eggs.
During the ninth month, reproduction resulted in viable eggs occurring in the freshwater control group and two tanks with salinities of 10 ppt. Light orange colored eggs were found in the mouths of females in tanks with salinities of 20 ppt, but the eggs were not viable. The fish in one tank suffered a mass mortality in month seven, so it was removed from reproduction computations. Reproduction also occurred during the ninth month in the freshwater control groups. Light orange colored eggs were found in the mouths of females in tanks with salinities of 20 ppt, but the eggs were not viable. Eggs with a grayish tint were found in the mouths of females in tanks with salinities of 30 ppt, but the eggs were also not viable. One high salinity tank was removed after nine months due to disease, but females were holding eggs with a gray color and eggs were examined and found not to be viable. No reproduction occurred in tanks with salinities of 20 ppt or higher during the experiment. Weight gain was shown to be positive and linear with salinity. The control group had the least weight gain with a final mean weight gain of 565 grams per tank. In tanks with salinities of 10 ppt, final mean weight gain of the fish was 697 grams; and in tanks with water salinities of 20 ppt, a final mean weight gain of the fish was 815 grams at the close of the experiment. Fish within tanks with salinities of 30 ppt, showed the most gain, with a mean weight gain of 927 grams these differences were shown to be statistically significant (P< .004).
Morphological changes and the occurrence of disease were evident between the fish in the control tanks and the fish in all other tanks. Tank 3, with 20 ppt salinity developed bacterial septicemia, caused by Streptococcus sp .. This disease produced some lesions, enlarged heads and sunken bellies as well as a dark green cast to the dorsal area. During the eighth month, the fish in a tank with salinity of 30 ppt developed a toxic algae bloom and the fish contracted a disease, which manifested itself by producing epithelial erosion, highly suggestive of the dinoflagellate pathogen Pfiesteria piscicida. Within a week, nine of the ten fish suffered severe epithelial loss and were close to death. Other changes accompanying increased salinity were brighter red flashing on the dorsal and pectoral fins and tail.
Thus the results are consistent with a hypothesis that higher salinity severely restricts reproduction and increases growth rates, but it was also appears that increased disease accompanies increased salinity. Thus the use of saltwater does not appear to be advantageous for the culture of this species.
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Traver, Elizabeth. "Tree transpiration varies spatially in response to atmospheric and edaphic conditions." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1317325051&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Vanderburgh, Richard N. "One-Dimensional Kinetic Particle-In-Cell Simulations of Various Plasma Distributions." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610313011646245.
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Bain, Emily C. "Clean Air in South Texas: An Estimation of Biogenic Tropospheric Ozone Precursors Using Various Models." Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1033659160.
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Wilson, Aaron Benjamin. "Using the NCAR CAM 4 to Confirm SAM’s Modulation of the ENSO Teleconnection to Antarctica and Assess Changes to this Interaction during Various ENSO Flavor Events." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376919626.
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Andringa, Stephanie Lynn. "Ecology, Population Dynamics, and Sexual Characteristics of Commensal Leucothoid Amphipods with the Sponge Cliona varians in the Florida Keys (Crustacea: Amphipoda)." NSUWorks, 2015. http://nsuworks.nova.edu/occ_stuetd/28.
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Recent observations have identified a new species of leucothoid amphipod, Leucothoe “sp. F,” associated with the sponge Cliona varians. This project examined the relationship between this amphipod and its sponge host at three sites in the Florida Keys with differing hydrodynamic regimes. Ninety-eight sponge samples with a total of 2,030 amphipods were collected between December 2011 and September 2012. Leucothoe “sp. F” is currently a common species in the Florida Keys strongly associated with C. varians; its distribution strongly coincides with open tidal currents from the Gulf of Mexico. Seasonality, depth, and tidal regimes not only influence population dynamics and sexual characteristics of Leucothoe “sp. F,” but also the abundance and volume of its host.
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Huang, Kuo-Feng, and 黃國峰. "Characteristics of atmospheric boundary layers developed over various terrains." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/40166653497013764967.
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碩士淡江大學
土木工程學系碩士班
102
The simulation of turbulence boundary layers in this study can be divided into two parts. The first part is simulation of flow field developed over terrains that compliance with the definitions of the terrain categories in the building wind code. Since current field measurements can only provide reliable mean wind speed profile. Properly simulated turbulence boundary layer is the best and only viable means to acquire turbulence features of the atmospheric boundary layers. Besides simulating flow fields via scaled terrain models, the thesis further studied the procedure to develop equivalent floor roughness elements to generate turbulent boundary layers over urban, suburban and open terrains. The second part of this thesis is the wind tunnel simulation of wind field over complex terrain. A 1/5000 mountainous terrain model centered at Xiaopingding, tamsui in the northeastern corner of Taiwan was built. Wind tunnel measurements were then compared with field measurement of Lidar and numerical simulation by LES. The initial result indicates that wind tunnel simulation of rugged terrain has its limitations. In real life, hills and mountains are not homogenous terrains. The shape and geographic lay out of high mountains would significantly distort the approaching flow. This geographic effect can be extremely difficult properly simulated in a fixed sized wind tunnel test section. More works need to be done in this subject.
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(6630833), Zhenyu Shen. "Liquid Nitrate Fertilizer Production with Various Atmospheric Pressure Discharges." Thesis, 2019.
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Plasmas can be used to increase the probability of maturity of seeds and disinfect them. The water applied on plants can also be treated with plasma to reduce bacteria. Discharges normally used to treat water including dielectric barrier discharges, gliding arcs, DC, AC, or pulsed coronas, and various direct discharges in liquid. After treatments, reactive oxygen (ozone) and nitrogen species (nitrite and nitrate) will appear in the water solution. Then, by applied this water, the lifecycle of plant could be significantly influenced. Plasma has a great potential to play an important role in the agriculture discipline. The process of synthesizing nitrate fertilizer with water, air, and electric spark has been known for a long time. But due to low nitrate yield and high energy consumption, it was replaced by the Haber-Bosch process in the first half of the 20th century. The Haber-Bosch process, however, has several disadvantages: it requires natural gas as a raw material, fixes nitrogen in the form of ammonia, and generates oxycarbides as byproducts. Thus, the concept of manufacturing nitrogen fertilizer with only water, air and electricity is still appealing.
In this project, we want to measure the pH value and conductivity of the water treated by various atmospheric pressure discharges including the arc discharge, DC positive corona discharge, DC voltage driven cold plasma torch operating with helium, dielectric barrier discharge (DBD), and radio-frequency (RF) plasma. Also, it is necessary to verify the existence of different important species in the treated water such as peroxide, nitrite, and nitrate ions by measuring their concentrations. Based on current and voltage measurements and wall-plug electrical energy consumption, energy efficiency of nitrate synthesis was determined in these five plasma systems. Optical emission spectroscopy was employed to study the reaction kinetics of both DBD and RF discharge. Our goal is to produce enough nitrate ions, by plasma treatment with minimal energy input (the value should be at least close to the Haber-Bosch process), in water which could be further used as fertilizers.
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Ho, Chung-Yen, and 何忠諺. "Effect of the AlN-ZnO cosputtered films annealed under various atmosphere." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/4953un.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
97
Al-N codoped zinc oxide films were prepared using a radio-frequency magnetron cosputtering system using AlN and ZnO targets. The samples were annealed to achieve dopant atom activation in different ambient environments. Type and formation mechanism of free carrier in thin film were studied by electricity measurement , PL characteristic and chemical bonds. It can concluded the activation energy of the nitrogen (NO) acceptor and further understand the impurity activation mechanism at different annealing conditions with the aim of stable p-type ZnO.The undoped zinc oxide thin film after to pass through the different environment annealed treatment, By temperature-dependent Hall to gauge and the room temperature photoexcitation fluorescence spectrum knew that, it executes the body to activate the mechanism to control for oxygen vacancy (VO), but the aluminium nitride - zinc oxide cosputtered thin film to have the different activation mechanism under the different environment annealed treatment. After the nitrogen environment annealed treatment cosputtered thin film its electricity characteristic gauging result for the stable p thin film, also controls (~1.93 eV) by the NO correlation radiative transition, but the oxygen environment annealed treatment cosputtered thin film although may compensate in the thin film effectively the oxygen vacancy flaw, but is unable to obtain the characteristic good p electric conduction state, under the vacuum environment annealed treatment cosputtered thin film to present n of electric conduction state the highly concentrated, Finally the atmospheric environment annealed treatment cosputtered thin film to be insufficient to reverse the thin film the electric conduction state.Because of temperature-dependent Hall to gauge, the acceptor nitrogen atom machine-made activation energy which calculates is 160 meV, the aluminium atom machine-made activation energy is 52 meV. Moreover, the low temperature fluorescence spectrum gauging altogether splashes after the nitrogen environment annealed treatment plates the thin film to gauge and A0X of the acceptor nitrogen atom correlation fluorescence peak value, Altogether splashes after the vacuum environment annealed treatment plates the thin film then the quantity aluminium leaves the atomic correlation D0X of with fluorescence peak value, and calculates the acceptor nitrogen atom activation energy based on the photon energy formula is 168 meV. In addition, use light electronic energy spectrometer gauging result, Also may observe from the N1s photoelectron axle territory to the nitrogen atom activates binding energy of the (NO) is 398.3 eV. The XRD gauging result showed the thin film crystallizes the change in sexuality after the annealed treatment to be good, ZnO(101) peak toward diffraction low angle, and altogether splashes after the nitrogen of new structure.
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LI, JIA-HONG, and 李嘉宏. "A Modeling Study on Atmospheric PM2.5 Affected by Various Meteorological Conditions in Taiwan." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5d2j9c.
Full textAbstract:
碩士國立雲林科技大學
環境與安全衛生工程系
107
In recent years, the air quality in Taiwan has received more attention from the people and the government.However, anthropogenic emissions and meteorological conditions have a significant impact on air quality, and adverse meteorological conditions may offset efforts to anthropogenic emissions control. This study used CMAQ to simulate the impact of meteorological changes in 2013 and 2016 on PM2.5 concentrations and estimated the impact of anthropogenic emissions changes on air pollutants that evaluated the effectiveness of anthropogenic emissions control. The impact of PM2.5 on various emission sectors with various weather patterns is different. In order to set emergency measures according to various weather patterns. Therefore, this study will explore the impact of 46 emission sectors in 2010 and 18 emission sectors in 2013 on PM2.5 in the Kaopin air basin under various weather patterns. The results show that compare with the PM2.5 observations in 2016 and 2013, the average annual concentration of PM2.5 in Taiwan decline by 5 µg/m3 and the meteorological changes in 2016 and 2013 cause the PM2.5 concentration to decline by 1.3 µg/m3. Therefore, it estimate that anthropogenic emissions changes in 2016 and 2013 may result in PM2.5 concentration decline by 3.8 µg/m3. For all air basin in Taiwan, the PM2.5 concentration increase by 0.68-2.8 µg/m3 in the Northern, Chumiao and Yilan air basin due to meteorological changes. In the other air basin, the PM2.5 concentration decline by 0.84-5.6 µg/m3, which the most decline of PM2.5 concentration is in the Yunchainan air basin by up to 5.6 µg/m3. In all air basins, the concentration of PM2.5 due to anthropogenic emissions changes decline by 0.48-9.2 µg/m3, which the most decline of PM2.5 concentration is in the Yilan air basin by up to 9.2 µg/m3. It shows that it is effective in reducing emissions from anthropogenic emissions in East Asia. Overall, the meteorological changes have led to increase of PM2.5 concentrations in northern Taiwan, which has offset the efforts of East Asian anthropogenic emissions control. However, meteorological changes and anthropogenic emissions changes are beneficial to decline of PM2.5 concentration in central and southern Taiwan. Exploring the impact of various emission sectors on PM2.5 in the Kaopin air basin under various weather patterns in 2010 and 2013. The Kaopin air basin is prone to happen PM2.5 high pollution events under high pressure reflux and standard northeast monsoon. In the case of off-shored high pressure and weak northeast monsoon, it is more prone to happen serious PM2.5 pollution events. According to the various weather patterns, the impact of PM2.5 from various emission sectors is different. The Kaopin air basin in Weak northeast monsoon and Standard northeast monsoon is affected by Taiwan local about 61-68%, mainly affected by large trucks (11-12%), vehicles driving dust (4-8%) and power industry (2-4%). In high pressure reflux is affected by Taiwan local about 69-71%, mainly affected by large trucks (9-10%), chemical materials industry (4-6%) and power industry (5-8%). In off-shored high pressure is affected by Taiwan local about 49-55%, mainly affected by large trucks (6-11%), vehicles driving dust (3-5%), and power industry (4%). Overall, the Kaopin air basin happen PM2.5 high pollution events under high pressure reflux is the most affected by Taiwan local. Therefore, when PM2.5 pollution occurs under high pressure reflux that implement emergency measures to reduce local emission sectors in Taiwan can more improve air quality. In the case of off-shored high pressure in Kaopin air basin, it is the least affected by Taiwan local. If it is necessary to implement emergency measures to reduce local emission sectors in Taiwan can not effective improve air quality.
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Chiu, Han-Chin, and 邱漢欽. "Electrochemical characteristics and structure of orthorhombic LiMnO2 via synthesis of various atmosphere, grinding, and heat treatment." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/33723084170051316941.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系碩博士班
93
Pure and no monoclinic phase of orthorhombic LiMnO2 is hard to be prepared. It is usually synthesized by precursor under inert or reduced atmosphere. We first prepare the precursor via citrate process and the powder is calcined under 99% Argon mixed with 1% hydrogen flow-gas to produce pure orthorhombic LiMnO2. From the XRD pattern, we find that there is no intensity on the diffraction angle of 18.3° and is no boardening on 24.8°. Compared to the powder synthesized under pure Argon flow-gas, the pure O-LiMnO2 seems reveal low capacity 140mAg-1 that contains monocline impurity inside is 150mAg-1. Ball-milling and heat treatment on the above two powders can improve the electrochemical behavior through the analysis of charge-discharge cycling test and A.C. impedance. After all, this cathode material of Li-ion battery will be more deeply known.
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PENG, CHEN-AN, and 彭晨安. "A Modeling Study on Atmospheric Ozone and Its Precursors Contributed by Various Sources in Taiwan." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/xw4p24.
Full textAbstract:
碩士國立雲林科技大學
環境與安全衛生工程系
107
In recent years, The economy of Asia has developed rapidly, and air pollutant emissions have also increased. Ozone is also one of other important air pollutant. In addition to its local effect in Taiwan, Taiwan is also affected by long range transport (LRT). To solve the problem of ozone pollution, in addition to controlling local emissions in Taiwan, the impact of LRT on Taiwan can not be ignored. This study used CMAQ-ISAM to conduct the various sources (point, line, area, and biological sources) simulations in Taiwan to understand the nitrogen oxides (NOx), volatile organic compounds (VOCs), daily maximum ozone (DMO3) and maximum daily 8 hour ozone (MDA8O3) are affected by various sources. Since various source affected ozone is different, therefore it is understood that the ozone affected by various sources are controlled by its NOx concentration or VOC concentration. In addition, due to the serious ozone pollution in Kaopin air basin, a more detailed simulation of Kaopin air basin is conduct to understand the Kaopin air basin local impact, the other air basin impact and the LRT impact to Kaopin air basin ozone concentration. The results show the various source of NOx in Taiwan in 2013, the line impact is the largest source, followed by the point source ; VOCs is the most affected by the area source,while DMO3 and MDA8O3 are affected by boundary condition (75-79%), followed by line source (6-7%). The DMO3 in each air basin is affected by Taiwan local about 8-28%, the highest impact is in the Northern and Central air basin, and the lowest impact is in the Huadong air basin; MDA8O3 is affected by Taiwan local about 6-24%. It also shows that each air basin DMO3 and MDA8O3 are affected by the boundary condition, and the proportion of MDA8O3 affected by the boundary condition is higher than DMO3, indicating that MDA8O3 is more affected by LRT than DMO3. The results of NOx and VOC control of various sources on ozone show that the various sources of DMO3 and MDA8O3 are mainly affected by VOC control in Taiwan According to the impact statistics in Taiwan in 2013, both DMO3 and MDA8O3 sources are also mainly VOC control, but the proportion of NOx control affected by various source of MDA8O3 has increased, which means that 8 hours of ozone is more affected by NOx concentration. The results of various sources on the ozone concentration of each station show that DMO3 and MDA8O3 in mountainous stations are the most affected by Taiwan local (40%), and the eastern stations are the lowest (8%), while sea stations are more affected by boundary condition than urban stations. Each station is affected by various sources only in Hualien Station and Taitung Station are NOx control, the other stations are VOC control. According to the results of different levels of DMO3 and MDA8O3 pollution events are affected by anthropogenic sources, the average annual anthropogenic source NOx control impact ratio of DMO3 and MDA8O3 in Kaopin air basin is 25-26%. With the increase of pollution level, the proportion of anthropogenic NOx control is getting higher and higher. The maximum NOx control impact can be about 36-37%, indicating that when ozone pollution becomes more and more serious, the influence of anthropogenic sources tends to be NOx control. A more detailed simulation in Kaopin air basin shows that the DMO3 concentration in Kaopin air basin is affected by its local by about 10%, the other air basin impact is about 18%, and the boundary condition impact is about 69%; MDA8O3 is affected by its local by about 8%, the other air basin impact is about 15%, and 73% of the boundary condition impact. In view of Taiwan local impact in Kaopin air basin, about 30% of the ozone concentration comes from Kaopin air basin local impact, and 70% comes from the other air basin impact.
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Hsieh, Chia-Lin, and 謝佳霖. "Uncertainty on the relative contribution to atmospheric HAP risk assessment concentration result from various emission types." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/68525240099951068353.
Full textAbstract:
碩士國立雲林科技大學
環境與安全工程技術研究所
87
In Hazardous Air Pollutant (HAP) risk assessment procedure, it would have some difficulties to measure the concentration distribution in atmospheric environment due to the limit of temporal, spatial, personal resource & expenditure. Therefore, concentration distribution has to be resolved by air diffusion models before exposure assessment. However, most of air diffusion models, the applicability of models intrinsic parameters, the variance of parameter selected by model user, and etc. The uncertainty factors could be propagated to form error assessment result. This study selected an incinerator and it''s vicinity as research target area. It was to find out the relative contribution ratio from various emission types by simulation results. In-site measurement will also conduct to find out the uncertainty of contribution and quantify the uncertainty propagation. Finally, the results to be used in procedure in risk assessment. This study provided several results as following: (1) The model uncertainty analysis resulted from meteorology parameters were proceed by ISCST2. The results showed that the largest uncertainty which come from stability, and total uncertainty was ±95%, (2) To simulate 95% the maximum concentration, grid must be less of four times tack height, (3) heavy metal concentrations from TaiChung incinerator is less. Pb almost comes from line source, Zn comes from point source, (4) While the procedure of health assessment to Taichung incinerator it was found the uncertainty source. To simulate Pb concentration uncertainty form line source is about 71 ~ 93%, and Zn concentration uncertainty form point source is about 27 ~ 81%.
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Fan, Chao-Jung, and 范釗榮. "Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47850399742706646333.
Full textAbstract:
碩士國立臺灣大學
地理環境資源學研究所
100
Abstract Eddy-covariance (EC) system has been used to measure exchange of scalars, momentum and energy components between land surface and atmosphere in the past decades. But the limitations and assumptions of EC method such as being a point-measurement make EC method uncertain over complex terrain. To systematically quantify area-averaged energy fluxes, comparing between energy fluxes measured by EC method and surface-layer scintillometer (SLS) over hilly terrain and estuarial grass marsh is studied in this research. SLS system applied Monin-Obukhov Similarity Theory (MOST) to estimate sensible heat fluxes by linking variances and covariances of laser beam intensity within path-length between laser transmitter and receiver and SLS system was established at Xitou flux tower during summer and winter, and at Guandu Nature Park during winter. Owing to the measurement within path-length, SLS system provides better spatial representative than conventional tower-based EC results. In this study, surface parameters and properties such as friction velocity, Bowen ratio and surface roughness length are investigated to understand the features of turbulence formation in each site. Results suggest the under-estimated sensible heat flux by scintillometer and an explanation to the difference of measurement is established under various atmospheric conditions. In this study, it’s concluded that at Xitou, SLS measures about 0.35 times of sensible heat flux to that by EC under stable state and the correlations y=0.76x2-0.56x+1.76 and y=1.56x2-2.07x+1.81 could describe the relationship between logarithm of stability and H ratio under unstable state in winter and summer respectively. At Guandu, the H ratio is constantly 0.9 under stable state and in correlation y=3.25e-0.044x-2.14 between logarithm of stability and H ratio under unstable state. The relationship between results of EC and SLS could be a linkage among tower-based studies and high-scale methods such as remote sensing and be estimated to be a base to regional micrometeorological modeling.
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SYU, FANG-CIH, and 許芳慈. "A modeling study on the atmospheric PM2.5 affected from various sources in Taiwan using decoupled direct method." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/48984315494879531735.
Full textAbstract:
碩士國立雲林科技大學
環境與安全衛生工程系
104
In recent years, the fine particulate matters (PM2.5) impact on air quality and human health very important. For the significant issue, in May, 2012, the Taiwan’s EPA stipulated the PM2.5 standards, 15 μg/m3 per year and 35 μg/m3 per day. Realizing how to achieve the PM2.5 standards should assess the PM2.5 influence on air quality form the major sources, and against different emission characteristics develop different control strategies to effectively control air pollution. Therefore, the study discussed the atmospheric PM2.5 affected from various sources in Taiwan. The study used CMAQ model with the decoupled direct method (DDM) to evaluate the domestic important source on air quality in Taiwan, in 2010. Taiwan air pollution source could be divided into point, line and area source by the pollution type. And whole sources subdivided into 46 categories, the effects of the highest concentration is area source (7.85 μg/m3, 29.2%) , the second is line source (5.13 μg/m3, 19.1%), and the lowest effect is point source (4.46 μg/m3, 16.6%). The iron and steel industry account for point categories at the highest (19%), the big truck account for line categories at the highest (28%), the catering industry account for area categories at the highest (32%). According to simulation result of base case select PM2.5 pollution episodes to evaluate the PM2.5 pollution episodes affected from power plants in Taiwan. The simulation results suggested that power plants impact on Taiwan PM2.5 concentration is 0.76 μg/m3, the ratio is 2.82%, and the ratio increased to 3.24% during PM2.5 pollution episodes. Among the all PM2.5 pollution episodes, very hight pollution episodes has the highest proportion; hight pollution episodes come as the second, and the lowest is medium pollution episodes, the ratio is 3.46%, 3.34% and 3.16%, respectively. During hight pollution episodes, some of site the influence concentrations increase from power plants, but the ratio is reduced. Indicate that influence is increase from other sources, lead to influence is reduce from other sources.
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Ju, Long-Tsong, and 朱榮聰. "Effects of TiC and Sintering Atmosphere on Properties of 316L Stainless Steels Controlled by Various Molding Processes of Powder Metallurgy." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/16901680552763001759.
Full textAbstract:
碩士義守大學
材料科學與工程學系
91
Corrosion resistance and ductility of 316L low carbon austenitic stainless steel are good. However, the strength, hardness, grind-resisting…in mechanical properties are all poorer. In order to certainly control the alloy components and improve matrix this experiment uses two manufacturing processes about steel,i.e. die cold press and injection molding of powder metallurgy. There are two most important work of this research. One is adding TiC to reinforce phase and properties. In addition, finding the best content of two processes,respectively. The other is nitridation which can improve mechanical properties. So the sintering atmosphere controlled (hydrogen transfer to nitrogen) was used in order to seek the best transferable temperature and isothermal holding time. Finally , many different mechanical property tests, phase examinations, content analysis, structure analysis have been done in order to understand the better condition. The results from experimental investigation show that grain size was effectively reduced and there was reinforce phase with the addition of TiC. A highest nitrogen content was obtained and mechanical properties of 316L stainless steel were improved by sintering atmosphere controlled (H2→H2+N2) with wonderful transferable temperature. Fortunately, we also find out the best TiC content(PM：2wt%、PIM：3wt%) and transferable temperature of two various processes（1200℃）.
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chun, Chuang Hsiang, and 莊翔鈞. "A study of the ZnO buffer layer annealed under various atmosphere and its effect on the post-deposition cosputtering films." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/5z43vp.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
96
In this study, the ZnO bufferl layer were grown on Si(100) substrate by the reactive RF magnetron sputtering. In addition,the annealing at 300oC to 700 oC under oxygen(O2), nitrogen(N2) and Hydrogen(H2) respectively. That were improve the ZnO buffer layer internal structure defects. The result of study, the X-ray diffraction peak angles of ZnObuffer layer with (002) orientation as a function of annealing temperature. That the high thermal annealing has the effects of narrowing the diffraction peak, indicating that grain growth has occurred. The stress in ZnO buffer layer changes from compressive to tensile with the increase of room temperature to 700 oC.The ZnO buffer layer obtainsthe tensile stress quantity for to be highest at annealing under Hydrogen environment. The Photoluminescence spectra have two bands of luminescent peaks. One band is located in the range of UV and violet light. The other band consisted of green luminescence. The thin film crystallinity is affects the UV emission intensity the main reason. The various ZnO buffer layer crystallinity gradually strengthens along with the heat treatment temperature rise to bring about the UV emission region enhancement. The green luminescence of ZnO is related to oxygen vacancies(Vo). Therefore has the highest relative peak value by the hydrogen heat treatment ZnO buffer layer, Because hydrogen heat treatment for increases the oxygen vacancy(Vo).Because oxygen heat treatment for decrease the oxygen vacancy(Vo), so that has the lower relative peak value by the hydrogen heat treatment ZnO buffer layer. We report a buffering method of improving the quality of ITO thin flms on Si by r.f. magnetron sputtering. By applying a ZnO buffer before the ITO deposition in the same run of sputtering.Room-temperature Hall effect measurements showed that a increase of carrier density and decrease of mobility.It is evident to argue that increasing the ITO crystallinity is one way to increase the free carrier concentration since, with a more crystalline structure, there will be increased Sn solubility and less scattering centers. The slightly increased carrier concentration may come from the increased Sn solubility in In2O3 matrix. Indium zinc oxide (IZO) thin films at atomic ratios Zn：In at.33 % were doping on the ZnO buffer layer by rf cosputtering system at room temperature using indium tin oxide (ITO) and zinc oxide (ZnO) targets.We can observe increased the X-ray diffraction peak angles of Indium zinc oxide (IZO) doping on ZnO buffer layer with (002) orientation as a function. The carrier concentration decrease of Indium zinc oxide (IZO) thin films on ZnO-buffer Si comes from the drastic improvement of the crystal structure. It will be to restrain ITO co-doping to enter Indium zinc oxide (IZO) thin films. In addition, AlN codoped ZnO thin films on the ZnO buffer layers by the reactive RF magnetron sputtering. To investigate the effect of homo-buffer layer on the crystallinity of N–Al codoped ZnO films, XRD analysis exhibit high preferential orientation of (002) plane, indicating their good crystallinity and the value of full-width at halfmaximum (FWHM) of the N–Al codoped film is much lower, so that grain growth has occurred. AlN codoped ZnO thin films grown with the buffer layer has a much lower carrier concentration and a higher carrier mobility than that without buffer layer. The results indicate that the ZnO film grown with buffer layer has fewer defects which act as donors. The introduction of buffer layer can suppress evidently the generation of defects and dislocations derived from the large lattice mismatch and the difference of thermal expansion coefficients between ZnO and substrate.
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Shih, Wei Yu, and 施韋羽. "Variations of urban fine suspended particulate matter (PM2.5) from various environmental factors and sources and its role on atmospheric visibility in Taiwan." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/43849551036656099287.
Full textAbstract:
碩士國立中央大學
環境工程研究所
101
The characteristics and source contributions are very important in residents’ health effect and source control. This work compiles 63 samples of PM2.5 mass and speciations manually collected at three air quality monitoring stations (Xinzhuang, Chungming, and Siaogang) located in the metropolitan areas of northern, central, and southern Taiwan from March 9, 2011 to March 29, 2012. The aim of this work is studying seasonal variations of urban PM2.5, the effects of various measurement methods and instrumental units, different weather types, and potential source contributions on PM2.5. Moreover, the relationship of various PM2.5 speciations and sources with visibility is also investigated. The results show that the highest PM2.5 mass concentrations at the Xinzhuang and Chungming stations are occurred in spring, while that of the Siaogang station is in winter. For the weather patterns results, the sources of Xinzhuang and Chungming stations are contributed from local sources as well as long-range transport of Asian continent based on weather pattern analysis. In contrast, Siaogang station is affected locally plus poor ventilation in the environment. The major species is SO42- in almost all the stations and seasons except for the summer. Organic carbon concentration is very close to SO42- and highest vaporization proportion of NO3- is observed in summer while other volatile ions are without seasonal variations. For the whole observation study, the collected PM2.5 concentration is the lowest when using R&;P 2000 FRM (Federal Reference Method), highest for referring to the data of air quality stations, and in the middle for the data from R&;P2300 speciation sampler. In addition, the differences among sampling methods become wider when the collected concentrations are higher. The deviations between R&;P2000 and R&;P2300 are inferred to be affected by honeycomb denuders installed in the R&;P 2300 sampler. High PM2.5 concentration was observed in the north for the weather patterns of High Pressure Peripheral Circulation (HPPC), High Pressure system Pushing (HPP), and Warm area Ahead of a cold Front coupling with Weak Southern Wind (WAF+WSW) based on the weather pattern analysis (Chuang et al., 2008). Lower PM2.5 concentration frequently occurred in the periods of Northeastern and Southwest monsoons. In contrast, high PM2.5 concentrations were normally appeared in HPPC, HPP, and Northeastern monsoon and low for WAF+WSW and Southwestern monsoon in the central and southern Taiwan. Six source types were resolved from PMF (U.S. EPA, 2008) (Positive Matrix Factorization) source apportionment for all three stations. Secondary nitrate and chloride contributed highest followed by Secondary sulfate, Gasoline emission, Soil dust, Diesel emission, and Biomass burning. Multiple regression analysis on atmospheric visibility using PM2.5 species, sources types, and environmental factors showed that visibility is mainly reduced by the water content deliquesced from secondary inorganic ions. In summary, Taiwan urban PM2.5 is varied by seasons and weather patterns. Traffic emissions contributed significantly to atmospheric PM2.5, which may help the authorities in urban pollution control and assessment. Moreover, secondary inorganic ions are significant in reducing urban visibility.