Tesis sobre el tema "Moisture"
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Mwesigwa, Enosh. "Permeation of moisture through moisture barrier coatings". Thesis, University College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435802.
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Kankanala, Sujitha. "Advanced Moisture Control : Moisture measurement in textiles". Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-97939.
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Waichungo, Wamwarī W. "Textural characteristics of low moisture-crisp foods during moisture sorption and storage /". free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9823333.
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Sherratt, David Joseph. "Regional soil moisture modelling". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/8230.
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He, Xiao. "Moisture sorption and gas emissions during the storage of high moisture woody biomass". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44228.
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Moisture sorption and gas emissions are major processes associated with biomass storage. Depending on the storage conditions, these processes alter the structure and composition of biomass. The objectives of this research are (1) to develop moisture relations for woody biomass exposed to drying and wetting environments; (2) to quantify gas emissions from biomass stored under aerobic and anaerobic conditions; and (3) to develop dry matter loss equations for the stored biomass. Moisture adsorption and desorption (drying) experiments were carried out on Aspen branches in a controlled temperature and humidity chamber. Frequent wetting-drying cycles were simulated by spraying water on the biomass. A lump model for simulating moisture adsorption-desorption was developed and calibrated with experimental results. The model was applied to the Aspen bales stored for one year in the field under natural conditions. The predicted moisture contents using the lump moisture transfer model were found to be in reasonably good agreement with the moisture contents measured in the stored bales. In another set of experiments, gas emissions from stored Western Red Cedar (WRC) and Douglas fir (DF) were analyzed. The emissions of CO₂, CO, H₂ and CH₄, and the depletion of O₂ were measured. The highest total CO₂ emissions from WRC stored in the non-aerobic and aerobic reactors were 2.8 g/kg DM and 6.6 g/kg DM, respectively. Higher gas emissions were measured from stored DF materials than from WRC. Common volatile organic compounds (VOCs) measured using GC-MS were methanol, aldehydes, terpene, acid, acetone, hexane, ketone, benzene, ethers and esters from WRC and DF. The total VOC concentrations were found to have a positive correlation with temperature. The results of microbial analysis were compatible with gas emission results. Positive correlations between percent dry matter losses and gas emissions were found for both aerobic and non-aerobic storage conditions. The summation of gas emissions from aerobic reactors is greater than accumulated gas emissions from non-aerobic reactors over the same storage period. It was found that DF is more readily degradable than WRC. Greens (leaves and twigs) degrade faster than wood chips.
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Omotere, Olumide Olubunmi. "Improvement of the Soil Moisture Diagnostic Equation for Estimating Root-Zone Soil Moisture". Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157607/.
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Soil moisture information can be used accurately in determining the timing and amount of irrigation applied to plants. Pan and Pan et al. proposed a robust and simple daily diagnostic equation for estimating daily soil moisture. The diagnostic equation evaluates the relationship between the soil moisture loss function and the summation weighted average of precipitation. The loss function uses the sinusoidal wave function which employs day of the year (DOY) to evaluate the seasonal variation in soil moisture loss for a given year. This was incorporated into the daily diagnostic equation to estimate the daily soil moisture for a location. Solar radiation is an energy source that drives the energy and water exchanges between vegetation and the atmosphere (i.e., evapotranspiration), and thus impacts the soil moisture dry-down. In this paper, two parameters (the actual solar radiation and the clear sky solar radiation) are introduced into loss function coefficient to improve the estimation of soil moisture. After the Introduction of the solar radiation data into soil moisture loss function, a slight improvement was observed in the estimated daily soil moisture. Pan observed that generally the correlation coefficient between the estimated and the observed soil moisture is above 0.75 and the root mean square error is below 5.0 (%v/v). The introduction solar radiation data (i.e. clear sky solar radiation and actual solar) improve the correlation coefficient average for all the sites evaluated by 0.03 when the root mean square error is generally below 4.5(%v/v) for the entire root zone.
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Soriano, Melissa. "Estimation of soil moisture in the southern united states in 2003 using multi-satellite remote sensing measurements". Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3361.
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Thesis (M.S.)--George Mason University, 2008.Vita: p. 65. Thesis director: John Qu. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth System Science. Title from PDF t.p. (viewed Jan. 11, 2009). Includes bibliographical references (p. 59-64). Also issued in print.
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Eakes, Donald Joseph. "Moisture stress conditioning, potassium nutrition, and tolerance of Salvia splendens 'Bonfire' to moisture stress". Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54350.
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The objective of this study was to determine the leaf water relations, gas exchange, and growth of the bedding plant salvia Salvia splendens 'Bonfire‘ as influenced by moisture stress conditioning (MSC - exposing plants to 4 sublethal dry-down cycles) and potassium (K) nutrition. Plants were fertilized with one of six K rates: 25, 75, 150, 300, 450, and 600 ppm as KCl in experiment one. Seven weeks after seeding plants were subjected to MSC. MSC and increasing K rate resulted in osmotic adjustment and increased cellular turgor potentials. Foliar K content increased as osmotic potentials decreased due to treatment. Although there was no interaction, MSC and high K rates both reduced transpiration (E), leaf conductance (g₁), and daily gravimetric water loss during well watered conditions. Greatest shoot dry weight occurred for plants grown with 300 ppm K and no-MSC.
Gas exchange of salvia as influenced by MSC during the onset of moisture stress was determined in experiment two. On day one following final irrigation, MSC plants had lower mid-day E, g₁, hourly gravimetric water loss per unit leaf area, and net photosynthesis (Pn) compared to controls, despite no differences in leaf water potential (ψ₁). Percentage of stomatal inhibition of Pn (SI) was greater for MSC plants than controls with no differences in mesophyllic resistance to CO₂ (rm). On day two, MSC plants had greater Pn, E, g₁, and hourly gravimetric water loss per unit leaf area, while SI and rm were lower than controls. MSC plants maintained positive Pn rates and turgor to lower ψ₁ than control plants. Water use efficiency (WUE) estimates for MSC plants were greater than for controls.
Salvia plants were fertilized with 75, 300, or 600 ppm K to determine the influence of K rate on gas exchange during the onset of moisture stress in a third experiment. On day one following final irrigation, plants grown with K rates of 300 and 600 ppm had lower E, g₁, hourly gravimetric water loss per unit leaf area, and Pn compared to 75 ppm K plants. On day two, 600 ppm K plants had greater Pn, E, and g₁ as the experiment was terminated compared to plants grown with 75 ppm K, although ψ₁ was similar. Potassium rate had little affect on WUE.Ph. D.
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Donahoe, Daniel Noel. "Moisture in multilayer ceramic capacitors". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2189.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Peralta, Perry Nacnac. "Nonisothermal moisture transport in wood". Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-09192008-063154/.
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Du, Boliang. "Sichuan fog -- architecture and moisture". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129859.
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Thesis: M. Arch., Massachusetts Institute of Technology, Department of Architecture, February, 2020Cataloged from student-submitted thesis.
Includes bibliographical references (page 139).
This thesis is sited in Chongqing city, the "Fog Capital" of China. Surrounded by the nearby mountains of the Sichuan Basin, the city experiences year-long cloudiness as a result of temperature inversion caused by the basin's convective layer being capped by a layer of air moving east across the Tibet Plateau. Located at the confluence of Yangzte River and Jialing River, the city is enshrouded with fog for over 100 days per year result from an abundant amount of moisture trapped by the valley and nearby parallel mountain ridges. By re-imagining the transportation facilities which connects the upper and lower town of the city, this thesis researches the relationship between architecture and atmosphere from micro to macro, synchronizes the traveling of people and air, celebrates the ephemerality of the experience of ambient light, and proposes a rush-hour experience of fog. As a manifesto of the architecture of moisture, three individual projects are created, which are "Cloud Bridge", "Air Gate" and "Fog Tunnel".
by Boliang Du.
M. Arch.
M.Arch. Massachusetts Institute of Technology, Department of Architecture
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Coleman, Brandon F. "High Moisture Extrusion of Oatmeal". DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1390.
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Oats are considered to be a highly nutritious breakfast food available to consumers. Heightened consumer interest in functional food products and advances in human nutrition have led to increased levels of interest in the development of new oat based products (Webster and Wood 2011). Developments in technology have led to manufacturing of instant oatmeal, making the product more convenient to consumers. Low moisture extrusion processing is one of the most widely used methods to produce ready to eat breakfast cereals; however, there has been little research carried out to determine if high moisture extrusion methods would be viable. This study evaluated the economic and technical feasibility to utilize high moisture extrusion processing to produce ready to eat oatmeal. A process economics evaluation included measuring the capital requirements to implement the system, process costing to estimate the weighted average unit cost, and net present value of high moisture extrusion production. The capital expense was significantly high. However, the unit cost is comparable to similar products in the market. The net present value of implementing the technology revealed a significant profit over the course of 20 years. Six different technical experiments were performed using a twin screw extruder, each experiment testing for the effect of different extrusion variables on finished product texture. Reference texture data was measured using a control product currently made in the industry using an alternative batch process. The processing parameters which seemed to have the biggest influence on product quality were high rates of water injection, low feed rate, high reaction zone temperature, reduction of particle size, and the use of functional ingredients in the formula. Technical hurdles such as low dwell times, steam plugging, and inconsistent feeding prevented complete starch gelatinization and the steady state of extrusion. Overall, the high moisture methodology did not yield product quality that was consistent and cannot be recommended for use.
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Schuster, Doug E. "Soil Moisture Effects on Supercellular Convective Initiation and Atmospheric Moisture in the Midwestern United States". Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1462232761.
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Jazayeri, Sina. "Measurement and monitoring of moisture content in timber and investigations of moisture gradients using dielectric measurements". Thesis, University of Bedfordshire, 1999. http://hdl.handle.net/10547/622156.
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This thesis addresses various issues in connection with the measurement of moisture content in timber. The early parts include long term experimentally based studies which culminated in producing recommendations to existing British Standards for equilibrium moisture content (EMC) of timber in internal environments. Findings consistently showed lower EMCs than existing recommended values; these are believed to be caused by socio-economic factors. Intermediate sections of the thesis continue with tests on electrical methods of moisture content measurement to establish a basis for comparability and the claimed accuracy of currently available moisture meters in the market. To this end, the performance of a wide range of resistance-type moisture meters in worldwide use was critically investigated under laboratory conditions - it was established that even under the strict controlled conditions of the study, large discrepancies are not uncommon (as great as 13% moisture content difference was observed). While some instruments consistently underestimated, others overestimated under identical conditions. Lack of agreed standards for species corrections and temperature correction factors were found to be the main cause of disagreement between the meters. Further discussions include the layout for a proposed standard in which agreed values for species and temperature correction factors would be established. In the latter part of the thesis moisture gradients in timber, the causes and the current methods of assessment are discussed. In particular, the performance of a leading brand capacitance-type moisture meter was systematically investigated both in the absence and in the presence of predetermined moisture gradients. It was established that moisture gradients severely affect the measured moisture content. A computer controlled capacitance measurement system based on resonance detection was developed to initially replicate the behaviour of conventional capacitance-type moisture meters, and to further investigate possible moisture gradient detection protocols. Two electrode designs were used in order to investigate methods by which moisture gradients could be detected. It was shown that a multi-plate electrode can be used to detect moisture gradients in timber to depths of at least 10 mm.
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Kutay, Muhammed Emin. "Modeling moisture transport in asphalt pavements". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2911.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ridley, Andrew Martin. "The measurement of soil moisture suction". Thesis, Imperial College London, 1993. http://hdl.handle.net/10044/1/7933.
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Zhang, Jizhe. "Moisture damage of aggregate-bitumen bonds". Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/32725/.
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Moisture damage of the asphalt mixture is defined as the loss of strength, stiffness and durability due to the presence of moisture (in a liquid or vapour state) leading to adhesive failure at the aggregate-bitumen interface and/or the cohesive failure within the bitumen or bitumen-filler mastic. The presence of moisture can accelerate the distress of asphalt pavement in several different modes, such as rutting, fatigue cracking, thermal cracking and the formation of potholes. In the field, the moisture damage normally happens first at the interface of two pavement layers or at the bottom of pavement layers and develops gradually upward. Once moisture has come into contact and interacted with the asphalt mixture, moisture damage could be developed by the following mechanisms: detachment, displacement, spontaneous emulsification, pore pressure, and hydraulic scour. It should be mentioned that moisture damage is not limited to only one mechanism but is the result of a combination of several mechanisms. As mentioned previously, the common modes of moisture damage of asphalt mixtures are a loss of adhesion between the aggregate and bitumen and/or a loss of cohesion in the mixture. Among these two failures, the adhesive failure is recognised as the main mode of moisture damage. Hence, the physico-chemical interactions between aggregates and bitumen in the presence of moisture are believed to partially govern the moisture sensitivity of asphalt mixtures, which can also affect the serviceability, performance and durability of the asphalt pavement. This thesis describes the work that was carried out with regard to the moisture damage evaluation of aggregate-bitumen bonds through different procedures. The fundamental properties of the individual material such as the chemical composition and rheological properties of bitumen, moisture absorption, surface morphology and mineralogical composition of aggregates were first characterised. Two types of equipment, namely the dynamic contact angle (DCA) analyser and dynamic vapour sorption (DVS) system were used for determining the surface energy of the bitumen and aggregates, respectively. The obtained surface energy results were then combined thermodynamically to determine the work of adhesion between aggregate and bitumen, and the reduction in the adhesive properties if water is introduced into the system. Three established mechanical tests consisting of the standard peel test, Pneumatic Adhesion Tensile Testing Instrument (PATTI) test and a pull off test were developed and redesigned to make sure that these tests are practical, reliable and feasible to measure the bonding strength of aggregate-bitumen combined specimens. The composite substrate peel test (CSPT) was developed to prepare composite substrates using crushed coarse aggregates as a more practical replacement for the aggregate substrates prepared from aggregate boulders. Finally, the moisture damage results from mechanical tests and thermodynamic results were compared and correlated with the basic physico-chemical properties of the original materials. The results showed that in the dry condition, all techniques used in this research, including the mechanical tests and the surface energy tests led to similar results, with bitumen rather than aggregates dominating the bonding properties of aggregate-bitumen systems. After moisture conditioning, the four mechanical tests, including standard peel test, CSPT, PATTI test and pull-off test showed similar moisture sensitivity ranking and failure surface results demonstrating the good correlation between these four tests. In addition, based on the comparison conducted, the four mechanical tests are all considered to be reliable to evaluate the moisture sensitivity of different aggregate-bitumen systems. However, based on the aggregates considered in this research, the moisture sensitivity parameters obtained from the surface energy tests are suggested unreliable to evaluate the moisture sensitivity of aggregate-bitumen systems.
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Straube, John Frederick. "Moisture control and enclosure wall systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0013/NQ30650.pdf.
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Åhs, Magnus. "Moisture redistribution in screeded concrete slabs /". Lund : Lund Institute of Technology, Division of Building Materials, 2006. http://www.byggnadsmaterial.lth.se/pdf/TVBM-3136.pdf.
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Snapir, Boris. "SAR remote sensing of soil Moisture". Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9253.
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Synthetic Aperture Radar (SAR) has been identified as a good candidate to
provide high-resolution soil moisture information over extended areas. SAR data
could be used as observations within a global Data Assimilation (DA) approach
to benefit applications such as hydrology and agriculture. Prior to developing an
operational DA system, one must tackle the following challenges of soil moisture
estimation with SAR: (1) the dependency of the measured radar signal on both soil
moisture and soil surface roughness which leads to an ill-conditioned inverse problem,
and (2) the difficulty in characterizing spatially/temporally surface roughness of
natural soils and its scattering contribution.
The objectives of this project are (1) to develop a roughness measurement method
to improve the spatial/temporal characterization of soil surface roughness, and (2)
to investigate to what extent the inverse problem can be solved by combining multipolarization,
multi-incidence, and/or multi-frequency radar measurements.
The first objective is achieved with a measurement method based on Structure
from Motion (SfM). It is tailored to monitor natural surface roughness changes which
have often been assumed negligible although without evidence.
The measurement method is flexible, a.ordable, straightforward and generates
Digital Elevation Models (DEMs) for a SAR-pixel-size plot with mm accuracy. A
new processing method based on band-filtering of the DEM and its 2D Power Spectral
Density (PSD) is proposed to compute the classical roughness parameters. Time
series of DEMs show that non-negligible changes in surface roughness can happen
within two months at scales relevant for microwave scattering.
The second objective is achieved using maximum likelihood fitting of the Oh
backscattering model to (1) full-polarimetric Radarsat-2 data and (2) simulated
multi-polarization / multi-incidence / multi-frequency radar data.
Model fitting with the Radarsat-2 images leads to poor soil moisture retrieval
which is related to inaccuracy of the Oh model. Model fitting with the simulated
data quantifies the amount of multilooking for di.erent combinations of measurements
needed to mitigate the critical e.ect of speckle on soil moisture uncertainty.
Results also suggest that dual-polarization measurements at L- and C-bands are a
promising combination to achieve the observation requirements of soil moisture.
In conclusion, the SfM method along with the recommended processing techniques
are good candidates to improve the characterization of surface roughness. A
combination of multi-polarization and multi-frequency radar measurements appears
to be a robust basis for a future Data Assimilation system for global soil moisture
monitoring.
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Watson, David William. "Monitoring moisture movement within modified concretes". Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/641.
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Lopez, G. F. G. "Convective drying and solid-moisture interactions". Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234903.
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Sivanendran, Shobana. "CFRP prestressed concrete exposed to moisture". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/270196.
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In environments of high moisture exposure, carbon fibre-reinforced polymer (CFRP) reinforcement is believed to be a good alternative to steel due to its non-corrosive properties. However the CFRP matrix experiences other types of changes, mechanical deterioration and transverse swelling, with exposure to moisture and sustained stresses. Specifically for structural applications, few studies have investigated the effects of moisture and stress-induced matrix-dominated changes to the CFRP-concrete bond when the CFRP rods are cast into concrete as prestressed reinforcement. Experiments were conducted to measure the transverse swelling and moisture uptake rates of stressed and unstressed CFRP rods immersed in water and concrete pore solution (CPS). CFRP rods were also embedded in concrete and immersed in water to observe whether the transverse swelling of the rods would cause the concrete to crack. Pull-out tests were conducted on stressed and unstressed CFRP rods cast in concrete cubes and immersed in water for up to 125 days. Six CFRP prestressed concrete prisms were fabricated, three were immersed in water for over 125 days and three were left in lab conditions before being tested in three-point bending. Moisture-induced transverse swelling did not appear to cause cracking of the concrete covering CFRP rods in water, contrary to the prediction of the thick-walled cylinder model, but possibly caused an increase in the CFRP-concrete radial contact pressure. The imposition of sustained bending stresses on wet CFRP rods was found to cause premature failure, believed to be a result of matrix softening and microcracking. These observations of swelling and matrix degradation were believed to affect the CFRP-concrete bond. The pull-out tests of unstressed CFRP rods indicated an increased likelihood for bond failure in the CFRP matrix with moisture exposure. This resulted in greater variations in the ultimate and residual bond stresses of the wet samples compared to the dry controls. For the prestressed pull-out samples, higher magnitudes of prestressing resulted in lower bond failure loads. Both outcomes are indicative of matrix weakening with moisture and stress exposure. However despite this, the three-point bending tests revealed no significant differences in behaviour between the wet and dry prestressed prisms. Although the wet prisms exhibited slightly greater variation in their post peak load behaviour compared to the dry prisms, in line with the observations from the pull-out tests. The work from this thesis reveals that despite observations of matrix deterioration and transverse swelling in CFRP rods exposed to moisture and stress, the effect of these changes to the overall behaviour of a CFRP prestressed concrete member are minimal. Any long-term effects are unlikely to cause significant changes to the behaviour of the member. However, the CFRP-concrete bond may be more variable in members exposed to moisture, which should be allowed for in the design process. Therefore CFRP is a promising alternative to steel reinforcement in high moisture environments, with good long-term durability.
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Karapanayiotis, Thanasis. "Synthesis of moisture scavenging polymer films". Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612878.
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Lewis, Michael G. "Localized Learning of Downscaled Soil Moisture". Thesis, George Mason University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10809236.
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If given the correct remotely sensed information, machine learning can accurately describe soil moisture conditions in a heterogeneous region at the large scale based on soil moisture readings at the small scale through rule transference across scale. This paper reviews an approach to increase soil moisture resolution over a sample region over Australia using the Soil Moisture Active Passive (SMAP) sensor and Landsat 8 only and a validation experiment using Sentinal-2 and the Advanced Microwave Scanning Radiometer (AMSR-E) over Nevada. This approach uses an inductive localized approach, replacing the need to obtain a deterministic model in favor of a learning model. This model is adaptable to heterogeneous conditions within a single scene unlike traditional polynomial fitting models and has fixed variables unlike most leaning models. For the purposes of this analysis, the SMAP 36 km soil moisture product is considered fully valid and accurate. Landsat bands coinciding in collection date with a SMAP capture are down sampled to match the resolution of the SMAP product. A series of indices describing the Soil-Vegetation-Atmosphere Triangle (SVAT) relationship are then produced, including two novel variables, using the down sampled Landsat bands. These indices are then related to the local coincident SMAP values to identify a series of rules or trees to identify the local rules defining the relationship between soil moisture and the indices. The defined rules are then applied to the Landsat image in the native Landsat resolution to determine local soil moisture. Ground truth comparison is done via a series of grids using point soil moisture samples and air-borne L-band Multibeam Radiometer (PLMR) observations done under the SMAPEx-5 campaign (Panciera 2013). This paper uses a random forest due to its highly accurate learning against local ground truth data yet easily understandable rules. The predictive power of the inferred learning soil moisture algorithm did well with a mean absolute error of 0.054 over an airborne L-band retrieved surface over the same region. The validation experiment also demonstrated a strong linkage to the soil moisture, but the algorithm suffered from a lack of training data over such a small site. However, soil moisture estimation still exhibited a mean average error (MAE) of 0.028, compared to a 0.129 MAE of a deterministic model built upon the Air Force Weather Model.
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Kwiatkowski, jerzy. "Moisture in buildings air-envelope interaction". Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0012/these.pdf.
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L'humidité relative de l'air est un des paramètres les plus importants ayant une influence sur le confort, la qualité de l'air intérieur et aussi sur la performance énergétique et la durabilité des enveloppes. Les matériaux qui adsorbent et désorbent l’humidité peuvent être utilisés pour modérer l’amplitude des variations de l’humidité relative et ainsi améliorer le climat intérieur et diminuer les consommations énergétiques. Le transfert de masse dans les matériaux hygroscopiques, même si il est pris dans les simulations dynamiques des bâtiments, il est simplifié. Négliger le transport de vapeur d'eau entre l'air et le matériel, ou appliquer des simplifications peut entraîner de graves erreurs dans l'estimation de l'humidité de l'air. L’objectif de ce travail de thèse est d’examiner les paramètres influençant l’échange hygrique entre l’air intérieur et les matériaux de construction dans des conditions normales d’utilisation. Ce travail a été divisé en deux parties : expérimentale et numérique. Comme les propriétés hygrique des matériaux ont un impact important sur les transferts de masse, des mesures détaillées de la perméabilité à la vapeur et de l’isotherme de sorption ont été effectué. Aussi les coefficients convectifs de transfert de masse ont été mesurés. Le critère d’absorption de masse a montré que le taux de celui-ci ne dépend pas seulement du matériel et des revêtements, mais aussi de la température et le mouvement d’air intérieure. L’expérimentation sur l’évaporation de l’eau sur la surface libre d’un liquide a montré que le coefficient convectif de transfert de masse dépend du potentiel de transfert. Il a été présenté que pour les petites différences dans le taux d'humidité relative, le coefficient de transport est plus petit. Les mesures du coefficient convectif de transfert de masse à partir d'un matériau mince hygroscopique ont montré que la valeur du coefficient ne dépend pas seulement de la différence dans le potentiel de transfert, mais aussi du niveau de potentiel. Pour la même différence, les coefficients convectifs de transfert ont des valeurs inférieures pour des faibles niveaux d'humidité relative. Il a également été montré que le coefficient convectif de transfert de masse a des valeurs inférieures pour les échantillons en position verticale que dans la position horizontale. Dans la dernière partie de cette thèse, un nouveau modèle numérique Humi-mur, pour les simulations du flux massique échangé entre l’air et le matériau a été développé et présenté. Le modèle permet une représentation précise des propriétés hygriques : la perméabilité à la vapeur d’eau et l’isotherme de sorption. L’aspect pratique du modèle l'Humi-mur a été présenté. Les résultats montrent que le tampon d'humidité dans les matériaux peut améliorer la perception de la qualité de l'air et empêcher la croissance microbiologique à la surface de l'enveloppe du bâtiment. Il a également été souligné que négliger les effets d'hystérésis de sorption sur les flux d'humidité peut entraîner de graves erreurs dans les calculsThe aim of this thesis was to study the mass exchange between indoor air and material. The influence of several factors on moisture transfer has been verified. Also the convective mass transfer dependency on the relative humidity condition and position of the material has been checked. Finally, a new module with the sorption hysteresis model, Humi-mur, for calculations of mass flow exchanged between indoor air and material has been developed, validated and integrated into the whole building simulation tool TRNSYS. This powerful tool was used to simulate a realistic room under real climatic conditions. The tests on mass uptake have shown that the rate of mass uptake depends not only on the material and coatings but also, some relationships between mass flux and air movement and temperature have been found. The experiment on water evaporation from a free liquid surface showed that the convective mass transfer coefficient depends on the driving potential value. It was presented that for the smaller difference in the relative humidity the transport coefficient is smaller. The measurements of the convective mass transfer coefficient from a thin hygroscopic material showed that the value of the coefficient depends not only on the difference in the driving potential but also on the level of the driving potential. For the same difference the convective transport coefficient has lower values for a lower level of relative humidity. It was also shown that the convective mass transfer coefficient has lower values for samples in a vertical position than in a horizontal position. Finally, the practical use of the Humi-mur model has been presented. The results show that moisture buffering materials can improve perceived indoor air quality and prevent microbiological growth at the surface of the building envelope. It was also pointed out that neglecting the effect of sorption hysteresis on moisture flux can lead to errors in calculations
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Koch, Maik. "Reliable moisture determination in power transformers /". Göttingen : Sierke, 2008. http://d-nb.info/990846946/04.
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Tickes, Barry R. "Moisture Loss from Uncovered Stored Alfalfa". College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/201021.
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Moisture loss from stacked alfalfa was measured at various times of the year and at various baling moistures. Total moisture loss over two month time periods varied from 4.5% to 8.3% with considerable fluctuation occurring due to environmental conditions.
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Martin, E. C., S. Husman, R. Wegener, P. Brown, K. Johnson y L. Schnakenberg. "Determining Soil Moisture for Irrigation Management". College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/210311.
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One key component in good irrigation management is the measurement of soil moisture to help determine when to irrigate. In this study, resistance blocks and tensiometers were compared to neutron probe readings to assess how well these devices followed soil moisture and whether the resistance blocks and /or tensiometers could be used to schedule irrigation in cotton production. The resistance blocks were placed at 6, 18, and 30 inches. Tensiometers were placed at 18 and 30 inches. The readings from the resistance blocks and tensiometers were compared to neutron probe readings taken at 6, 18, and 30 inches. The resistance blocks compared well with the neutron probe readings at the 6 inch and 30 inch depth. At the 18 inch depth, there was much scatter in the data. The tensiometers also showed good comparisons at 30 inches and poor comparisons at 18 inches.
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Nyman, Peter y Tomas Geuriya. "Fukt i byggnadsmaterial : Hur man förebygger fuktskador vid materialhantering på byggarbetsplatsen". Thesis, KTH, Byggteknik och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102113.
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Byggsektorn har fortfarande svårigheter med att hantera fuktproblematiken. Vi har valt att fokusera på hanteringen av material i produktion. Den informationssamling vi utfört ligger till grund för vår analys och slutsats. Vi har intervjuat flera olika entreprenörer från byggbranschen för att ge oss en helhetssyn av fuktsäkerheten ute på byggarbetsplatserna. Studien påvisar att det råder brister både på beställar- och entreprenörssidan. Vi ser att det finns potential för förbättring när det så krävs. Därför rekommenderar vi att högre krav ställs på fuktsäkerheten och att tydliga riktlinjer finns att följa. Den handbok som framtagits är riktat till att hjälpa yrkesarbetarna på entreprenörssidan att uppnå de krav som ställs. Handboken innehåller tillvägagångssätt för materialhantering och fuktkvotsmätning samt kritiska fuktvärden för olika material.The construction sector still has difficulties in dealing with moisture problems. We have chosen to focus on the material handling in the production phase at the building site. The information collection we performed is the basis for our analysis and conclusion. We have interviewed several contractors in the construction industry to give us a comprehensive view of the moisture safety out on construction sites. The study shows that there are shortcomings on both constructor- and contractor’s side. We see that there is a potential for improvement when it’s required. We recommend that greater demands are placed on the moisture safety and that clear guidelines are to follow. The handbook is directed at helping skilled workers in the contractor end to achieve the required demands. The handbook includes procedures for material handling and moisture measurements as well as critical moisture values for different materials.
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Gräff, Thomas. "Soil moisture dynamics and soil moisture controlled runoff processes at different spatial scales : from observation to modelling". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5447/.
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Soil moisture is a key state variable that controls runoff formation, infiltration and partitioning of radiation into latent and sensible heat. However, the experimental characterisation of near surface soil moisture patterns and their controls on runoff formation remains a challenge. This subject was one aspect of the BMBF-funded OPAQUE project (operational discharge and flooding predictions in head catchments). As part of that project the focus of this dissertation is on: (1) testing the methodology and feasibility of the Spatial TDR technology in producing soil moisture profiles along TDR probes, including an inversion technique of the recorded signal in heterogeneous field soils, (2) the analysis of spatial variability and temporal dynamics of soil moisture at the field scale including field experiments and hydrological modelling, (3) the application of models of different complexity for understanding soil moisture dynamics and its importance for runoff generation as well as for improving the prediction of runoff volumes.
To fulfil objective 1, several laboratory experiments were conducted to understand the influence of probe rod geometry and heterogeneities in the sampling volume under different wetness conditions. This includes a detailed analysis on how these error sources affect retrieval of soil moisture profiles in soils.
Concerning objective 2 a sampling strategy of two TDR clusters installed in the head water of the Wilde Weißeritz catchment (Eastern Ore Mountains, Germany) was used to investigate how well “the catchment state” can be characterised by means of distributed soil moisture data observed at the field scale. A grassland site and a forested site both located on gentle slopes were instrumented with two Spatial TDR clusters that consist of up to 39 TDR probes.
Process understanding was gained by modelling the interaction of evapotranspiration and soil moisture with the hydrological process model CATFLOW. A field scale irrigation experiment was carried out to investigate near subsurface processes at the hillslope scale. The interactions of soil moisture and runoff formation were analysed using discharge data from three nested catchments: the Becherbach with a size of 2 km², the Rehefeld catchment (17 km²) and the superordinate Ammelsdorf catchment (49 km²).
Statistical analyses including observations of pre-event runoff, soil moisture and different rainfall characteristics were employed to predict stream flow volume. On the different scales a strong correlation between the average soil moisture and the runoff coefficients of rainfall-runoff events could be found, which almost explains equivalent variability as the pre-event runoff. Furthermore, there was a strong correlation between surface soil moisture and subsurface wetness with a hysteretic behaviour between runoff soil moisture.
To fulfil objective 3 these findings were used in a generalised linear model (GLM) analysis which combines state variables describing the catchments antecedent wetness and variables describing the meteorological forcing in order to predict event runoff coefficients. GLM results were compared to simulations with the catchment model WaSiM ETH. Hereby were the model results of the GLMs always better than the simulations with WaSiM ETH. The GLM analysis indicated that the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore soil moisture controls on runoff generation and can be an important link between the scales. Long term monitoring of such sites could yield valuable information for flood warning and forecasting by identifying critical soil moisture conditions for the former and providing a better representation of the initial moisture conditions for the latter.Abflussentwicklung, Infiltration und die Umverteilung von Strahlung in latenten und sensiblen Wärmestrom werden maßgeblich durch die Bodenfeuchte der vadosen Zone gesteuert. Trotz allem, gibt s wenig Arbeiten die sich mit der experimentellen Charakterisierung der Bodenfeuchteverteilung und ihre Auswirkung auf die Abflussbildung beschäftigen. Der Fokus dieser Dissertation wurde darauf ausgerichtet: (1) die Methode des Spatial TDR und deren Anwendbarkeit einschließlich der Inversion des TDR Signals in heterogenen Böden zu prüfen, (2) die Analyse der räumlichen und zeitlichen Dynamik der Bodenfeuchte auf der Feldskala einschließlich Feldexperimenten und hydrologischer Modellierung, (3) der Aufbau verschiedener Modellanwendungen unterschiedlicher Komplexität um die Bodenfeuchtedynamiken und die Abflussentwicklung zu verstehen und die Vorhersage des Abflussvolumens zu verbessern. Um die Zielsetzung 1 zu erreichen, wurden verschiedene Laborversuche durchgeführt. Hierbei wurde der Einfluss der Sondenstabgeometrie und verschiedener Heterogenitäten im Messvolumen bei verschiedenen Feuchtegehalten untersucht. Dies beinhaltete eine detaillierte Analyse wie diese Fehlerquellen die Inversion des Bodenfeuchteprofils beeinflussen. Betreffend der Zielsetzung 2, wurden 2 TDR-Cluster in den Quellgebieten der Wilden Weißeritz installiert (Osterzgebirge) und untersucht, wie gut der Gebietszustand mit räumlich hochaufgelösten Bodenfeuchtedaten der Feldskala charakterisiert werden kann. Um die Interaktion zwischen Evapotranspiration und Bodenfeuchte zu untersuchen wurde das hydrologische Prozessmodell CATFLOW angewendet. Ein Beregnungsversuch wurde durchgeführt um die Zwischenabflussprozesse auf der Hangskala zu verstehen. Die Interaktion zwischen Bodenfeuchte und Abflussentwicklung wurde anhand von drei einander zugeordneten Einzugsgebieten analysiert. Statistische Analysen unter Berücksichtigung von Basisabfluss, Bodenvorfeuchte und verschiedenen Niederschlagscharakteristika wurden verwendet, um auf das Abflussvolumen zu schließen. Auf den verschiedenen Skalen konnte eine hohe Korrelation zwischen der mittleren Bodenfeuchte und dem Abflussbeiwert der Einzelereignisse festgestellt werden. Hierbei konnte die Bodenfeuchte genauso viel Variabilität erklären wie der Basisabfluss. Im Hinblick auf Zielsetzung 3 wurden “Generalised liner models” (GLM) genutzt. Dabei wurden Prädiktorvariablen die den Gebietszustand beschreiben und solche die die Meteorologische Randbedingungen beschreiben genutzt um den Abflussbeiwert zu schätzen. Die Ergebnisse der GLMs wurden mit Simulationsergebnissen des hydrologischen Gebietsmodells WaSiM ETH verglichen. Hierbei haben die GLMs eindeutig bessere Ergebnisse geliefert gegenüber den WaSiM Simulationen. Die GLM Analysen haben aufgezeigt, dass die verwendete Messstrategie mehrerer TDR-Cluster in typischen funktionalen Einheiten eine viel versprechende Methode ist, um den Einfluss der Bodenfeuchte auf die Abflussentwicklung zu verstehen und ein Bindeglied zwischen den Skalen darstellen zu können. Langzeitbeobachtungen solcher Standorte sind in der Lage wichtige Zusatzinformationen bei der Hochwasserwarnung und -vorhersage zu liefern durch die Identifizierung kritischer Gebietszustände für erstere und eine bessere Repräsentation der Vorfeuchte für letztere.
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Antonopoulos, Charalampos. "Low slope roofs : Moisture transfer in inverted roofs constantly exposed to high moisture loads and drainage systems". Thesis, KTH, Byggnadsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209672.
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Low slope roofs are roofs with an inclination between 1:16 and 1:4 and have been constructed and preferred for many years due to the benefits they present. The goal of the present work is to study the following problems of low slope roofs, as they are suggested by previous relevant theses and the current needs of the market. Moisture transfer in low slope roofs with constant exposure to high levels of relative humidity. Is protection against corrosion required for steel beams placed directly under the external membranes? If yes, what kind of protection is that? Roof drainage on low slope roofs The study of the first subject was based on simulations of this type of structures in order to see how external moisture affects the moisture level and the potential for corrosion on steel beams. The main goal was to conclude whether we can actually build inverted roofs with steel plates or beams lying right under the roof membrane and what kind of protection is more appropriate to apply, in case it is required. According to the literature review conducted on roof structures, corrosion and corrosion protection, as well as the results of the simulations, the main factor defining the corrosion potential is the indoor environment. Moreover, paint coating seems to be the indicated anticorrosive protection. Regarding drainage, the study focused on the literature review of the current situation, the solutions applied, the existing regulations and guidelines regarding the type of systems used (full flow or gravity, internal or external), the construction of drainage valleys (inclined or horizontal) and the placement and dimensioning of drains and overflows, in order to create a short handbook with issues to be considered by the roof engineer. The main conclusions are that drain valleys are suggested to be constructed completely horizontal, in order to facilitate the cooperation between drains, and that full-flow systems are more efficient than gravity ones and should be preferred, as long as the roof is not exposed to solid material and prone to its accumulation around drains (e.g. roofs covered with vegetation or stone ballast, with overhanging or nearby trees).
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El-Bishti, Magda Bashier. "Determination of soil moisture using dielectric soil moisture sensors : effect of soil temperature and implication for evaporation estimates". Thesis, University of Reading, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487102.
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The reliability and accuracy of several sensors that employ the relationship between dielectric constant and soil moisture constant, e, in particular capacitance sensors were investigated. Results obtained from laboratory examinations ,of a Theta probe, TP, selected as a representative model for capacitance sensors, suggested that the sensor output was affected by temperature variations, electrical conductivity levels, spatial variation in sample bulk density as well as the level of compaction of the soil surrounding the sensor's rods. Detailed in situ e data collected usmg capacitance sensors were used to calculate sub-daily estimates of evaporation, E, using the soil water balance method, combined with the zero-flux-plane (ZFP) approach, for plots of bare soil, rapeseed and a maize field. These sensors comprised Theta probes (TP), Profiles probes (PP), ECH20 probes (EP) and Aquaflex sensors (AF). / The field output data of these sensors were analysed and compared with e obtained with both, the gravimetric and neutron probe method. The absolute values of B as measured by the various capacitance sensors differed considerably. Furthermore, the outputs of these sensors (apart from the AF probes) were found to be affected by temperature, which would result in an anomalous course of diurnal E. Also, B-data were subject to noise which required smoothing to ensure a physically realistic variation in E, when compared to estimates with the Penman-Monteith equation, EPAf, and the eddy-covariance method (maize field). E was determined from diurnal changes in vertically integrated soil moisture content above the ZFP. Smoothed values of Bwere temperature-corrected using fieldbased and laboratory-based correction equations. A considerable difference between field- and laboratory-based temperature corrections procedures was noticed, and correction factors strongly depended on B. As this resulted in an overly complicated correction procedure, which consequently gave unreliable E-values, it was then decided to use a constant correction factor (based on the field correction procedure), for each capacitance probe. For the bare soil plot, with the exception ofPP and EP only Bprofiles obtained with the TP and AF sensors produced relatively reliable E values when compared to Enf. By contrast, when these capacitance sensors were used under a canopy, all sensors yielded satisfactory E-values. This was most likely caused by reduced amplitudes of soil temperatures under the canopy and the fact that the dimensions of most sensors do not allow installation in the top soil (~3-5cm) layer at which most evaporation would take place in bare soils. We therefore recommended that these sensors can be used for diurnal B measurements and E determination under canopy provided that an appropriate temperature-correction procedure for each sensor is applied. To obtain reliable Band E estimates in bare soil, more research needs to be done. For more reliable e and E estimations in bare soils further extensive field trials would be strongly advised
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Derome, Dominique. "Moisture occurrence in roof assemblies containing moisture storing insulation and its impact on the durability of building envelope". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/NQ47707.pdf.
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Wang, Lingli. "Remote sensing techniques for soil moisture and agricultural drought monitoring". Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/2991.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 151. Thesis director: John J. Qu. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth Systems and GeoInformation Sciences. Title from PDF t.p. (viewed June 30, 2008). Includes bibliographical references (p. 135-150). Also issued in print.
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Mocetti, Francesca. "Characterization of moisture susceptibility of asphaltic bitumen". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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La ricerca riguarda lo studio delle modifiche indotte dalla diffusione di acqua e umidità nelle pavimentazioni stradali con riferimento ai materiali bituminosi. Lo scopo è stato quello di analizzare le implicazioni che si sviluppano a livello chimico e reologico in vari bitumi. In questo progetto oltre alla fase sperimentale, è stato utilizzato un software per la simulazione agli elementi finiti. Per quanto concerne la fase di laboratorio, è stato sviluppato un nuovo protocollo di condizionamento. Tre diversi bitumi sono stati soggetti alla diffusione di acqua in forma liquida o vapore, a determinate condizioni ambientali e per svariati intervalli temporali. Grazie a l’utilizzo di due camere climatiche il condizionamento è stato realizzato in modo uniforme a precisi valori temperatura e umidità mantenuti stabili. I materiali analizzati: un bitume soft, uno hard, ed infine uno modificato con l’aggiunta di polimeri. Il dispositivo FTIR-ATR è stato utilizzato per la caratterizzazione chimica, mentre il comportamento reologico è stato analizzato tramite test eseguiti con il DSR. Le avanzate tecnologie presenti nel laboratorio della TU Delft hanno consentito di ottenere notevoli risultati. L’analisi è stata condotta con l’obiettivo di evidenziare i diversi cambiamenti indotti dalla diffusione di acqua liquida o vapore e per analizzare l’influenza della temperatura, del tipo del bitume e dell’incremento del tempo di condizionamento. Una analisi analoga è stata condotta parallelamente, con lo scopo di investigare la correlazione tra il processo di invecchiamento e la diffusione di umidità. Infine, la simulazione agli elementi finiti è stata sviluppata tramite il software CAPA-3D per analizzare il comportamento del bitume in periodi più estesi di diffusione di umidità. Inoltre, il comportamento dei bitumi è stato studiato anche in presenza di particelle di riempitivo. Particelle granitiche e calcaree sono state aggiunte ai bitumi in differenti percentuali.
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Feleki, Zsolt. "Moisture adsorption in 3D self-similar structures /". Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16890.
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Summers, Matthew Dean. "The role of moisture in spontaneous combustion /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Grunmann, Pablo Javier. "Variational data assimilation of soil moisture information". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2476.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Meteorology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ferguson, Timothy Patrick. "Moisture and Interfacial Adhesion in Microelectronic Assemblies". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5003.
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In this research, a systematic and multi-disciplinary study was conducted to understand the fundamental science of moisture-induced degradation of interfacial adhesion. The research is comprised of both experimental and modeling components of analysis and consists of four primary components. First, the moisture transport behavior within underfill adhesives is experimentally characterized and incorporated into a finite element model to depict the moisture ingress and interfacial moisture concentration for each respective level of moisture preconditioning. Second, the effect of moisture on the variation of the underfill elastic modulus is demonstrated and the physical mechanisms for the change identified. Third, the aggregate effect of moisture on the interfacial fracture toughness of underfill to both copper and FR-4 board substrates is determined. This includes the primary effect of moisture being physically present at the interface and the secondary effect of moisture changing the elastic modulus of the adhesive when absorbed. Last, the recovery of both the elastic modulus and interfacial fracture toughness from moisture preconditioning is assessed with reversible and irreversible components identified. Using adsorption theory in conjunction with fracture mechanics, an analytical model is developed that predicts the loss in interfacial fracture toughness as a function of moisture content. The model incorporates key parameters relevant to the problem of moisture in epoxy joints identified from the experimental portion of this research, including the interfacial hydrophobicity, epoxy nanopore density, saturation concentration, and density of water.
This research results in a comprehensive understanding of the primary mechanisms responsible for the interfacial degradation due to the presence of moisture. The experimental results obtained through this research provide definitive data for the electronics industry to use in their product design, failure analysis, and reliability modeling. The predictive model developed in this research provides a useful tool for developing new adhesives, innovative surface treatment methods, and effective protection methodologies for enhancing interfacial adhesion.
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Cave, Peter William. "Membrane moisture transfer in fuel cell humidifiers". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31580.
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High system cost and large size are two barriers preventing mainstream commercial viability of proton exchange membrane fuel cells. These barriers can be addressed by (a) improving water management in the cell for a higher power density at lower cost and (b) reducing the cost and size of balance of plant components. The cathode reactant humidification system directly affects the water management of the cell and is one of the most expensive balance of plant components in the system. A thermodynamic model of a cathode gas to gas membrane humidifier was implemented. The model considers two-phase heat and mass transfer along two parallel, one-dimensional channels in counter flow operation. A single channel humidifier was constructed with the capability of measuring temperature and dew point temperature profiles along the channel. Dew point profiles and the effect of flow rate on the outlet dew point were measured at 30, 50, and 70°C isothermal cases with fully saturated wet-side inlet conditions. Water flux across the membrane was constant along the channel and the outlet dew point decreased with dryside flow rate for all cases. The effect of wet-side flow rate was minor. The experimental data were compared to the thermodynamic model using membrane diffusivity from four published correlations and three different techniques. The different diffusivity correlations affected model predictions of moisture flux by up to 86%, demonstrating that fitted membrane parameters must be used if modeling accuracy is expected. Calculating diffusivity at the average membrane water content of the two sides of the membrane was shown to be a better approximation than using an average relative humidity. Also, the model over-predicted the outlet dew point more at lower temperatures than at higher temperatures compared to the experimental data. Finally, a 5kW humidifier design was simulated at a pressure of 1 atm with 65°C fully-saturated and 25°C completely-dry conditions at the wet-side and dry-side inlets, respectively. Analysis revealed that modeling moisture transfer using humidity ratio as a driving force can lead to unphysical results under non-isothermal conditions with high moisture flux. Pressure drop estimations using an all-vapour, Darcy friction factor analysis were very low compared to measured data and a fitted flow restriction equation was suggested. Keywords: humidifier, membrane, fuel cell, water management, mass transfer, single phaseApplied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Silins, Uldis. "Post-drainage peatland moisture and aeration dynamics". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21635.pdf.
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Simonson, Carey James. "Heat and moisture transfer in energy wheels". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/NQ27431.pdf.
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Ghavidel, Taghavi Shahriar. "Moisture effects on high performance polymer composites". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/MQ53347.pdf.
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Anderberg, Anders. "Moisture properties of self-levelling flooring compounds /". Lund: Lund Institute of Technology, Lund University, Division of Building Materials, 2004. http://www.byggnadsmaterial.lth.se/.
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Erlingby, Daniel. "Alternative forms of sill construction - regarding moisture". Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93612.
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Moisture is a recurring parameter in construction. It can have a direct impact on the final result of a construction in the form of damage caused by damp. This usually ensue great economical loss due to disruptions in the construction, mainly as delays and prolonged drying times. Aside from increased costs, the damage caused by damp can also impact the indoor climate and cause health issues for those who will live there. Management of the erected building can also be affected negatively as damage caused by damp brings with it large interferences. This creates an increasing interest for companies to develop moist secure solutions. This report has been written with the damage caused by damp, which can appear on a sill construction oftentimes on account of bad weather, in mind. The report will present different sill constructions used in construction today as well as other moist preventive solutions, such as weather protection, temporary damp protection and suggestions on different sill constructions. This examination report is written from the following questions at issue: Which sill construction should be chosen to reduce capillary suction of standing water? Which optional sill constructions or sill protections are available on the market?Fukt är en ständigt återkommande parameter i byggsammanhang. Fukt kan inverka direkt på det slutliga resultatet vid uppförandet av en byggnad i form av fuktskador. De orsakar ofta stora ekonomiska förluster på grund av de störningar som uppkommer under byggnationen, störningar som förlängda torktider och senareläggning av andra aktiviteter. Förutom ökade kostnader kan fuktskadorna påverka inneklimatet och skapa ohälsa för dem som vistas i byggnaden. Förvaltningen av den uppförda byggnaden kan drabbas negativt då fuktskador ofta medför stora ingrepp. Det skapar ett allt större intresse för företag att hitta fuktsäkra lösningar. Denna rapport har skrivits med avseende på de fuktskador som kan uppträda på en syllkonstruktion, ofta på grund av ogynnsamma väderförhållanden som nederbörd. Rapporten kommer att presentera olika syllkonstruktioner som finns på byggmarknaden idag, andra fuktskyddande åtgärder som väderskydd och tillfälliga fuktskydd. Förslag på syllkonstruktioner behandlas också i rapporten. Examensarbetet är skrivet utifrån frågeställningarna: Vilken syllkonstruktion ska väljas för att minska kapillärsugningen av fritt stående vatten? Vilka alternativa syllkonstruktioner eller syllskydd finns tillgängliga på marknaden?
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Erindi-Kati, Anila. "Remote sensing and root zone soil moisture". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84027.
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This study investigated the possibility of three approaches in determination of soil moisture in the root zone. The aim of the study was to contribute to the development of soil moisture monitoring methods to better help crop best management practices.Two fields were examined, one at the Macdonald Campus of McGill University and the other near St. Jean-sur-Richelieau. Three approaches were used; (1) a hand-held hyper-spectral sensor (350-2500 nm), (2) a Geonics RTM EM-38 conductivity meter and, (3) gravimetric soil moisture sampling.
The first experiment (at St. Jean-sur-Richelieu) investigated the possibility of monitoring soil moisture with the EM_38, in the presence of field elevation and soil texture. The second experiment (at Macdonald Campus) investigated the possibility of using hyper-spectral sensor data for determination of soil characteristics in the root zone, in the presence of such factors as (a) irrigation (main treatment), (b) nitrogen (sub-treatment), and (c) weed control (sub-sub-treatment). Statistical regression analyses and Artificial Neural Network models were used to select the best waveband region for determination of soil root zone moisture.
The coefficients of determination obtained by the statistical analyses ranged from 0.75 to 0.94. The wavebands most frequently identified by these analyses ranged from 1100 nm-1900 nm.
The performances of the ANN training models were considered acceptable (R2 from 0.6 to 0.8). The lack of sufficient data greatly impacts this approach.
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Papadopoulos, Anastasios K. "Nitrogen and moisture distributions under subirrigated soybeans". Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55520.
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A field lysimeter experiment was conducted on a sandy loam soil during the 1990 and 1991 growing seasons. The experiment tested the effects of different watertables on soybean yields, and on moisture distribution and nitrogen concentration of the soil profile. The watertable depths were 40, 60, 80, and 100 centimeters (cm).Yields were measured in terms of number of beans per plant, number of pods per plant, number of beans per pod, and seed protein content at harvest.
Soil samples collected at depths of 30 and 70 cm from the soil surface were analyzed for moisture content and NO$ sb3 sp-$-N and NH$ sb4 sp+$-N concentrations.
The experimental results showed that controlled watertable management increased the yield and decreased soil NO$ sb3 sp-$-N levels. The best results from the watertables tested were found to be at 60 and 80 cm. This is suggested as the range of watertable depths that should be maintained for optimum soybean production.
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Njie, Momodou. "Modelling soil moisture dynamics in vegetated soils". Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406159.
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Ibupoto, Khalil Ahmed. "Heat and moisture transfer during grain cooling". Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246684.
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