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Enhancing textile electrode performance : Regulating moisture management through textile structureBacke, Carin January 2017 (has links)
The medical field has been a part of the smart textile area for quite some time. With time come technological advancement and the two fields converge on more and more areas. One such area is that of using textile electrodes, textrodes, for measuring bioelectrical activity, such as heart rate for ECG analysis. There are many components that make for a successful textile electrode and though many studies have been made in the subject there are several aspects that still are difficult. By using textile electrodes the problem with skin irritation from electrolyte gels, commonly used for conventional electrodes, is avoided, however dry textrodes create disturbances in the output signal (heart rate) while subjected to movement and internal dimensional changes. The addition of moisture to a textrode has shown to decrease these intermittent disturbances but the knowledge about fundamental textile structural influence in the matter has not been fully investigated. This study investigates a flat, a 2-thread fleece and an open structure, and their relation to moisture both as textile structures and as textrodes. This way the possibilities of utilising moisture to increase performance in a textrode purpose can be examined and to what extent the textile structure plays a part in that exploitation. The material composition of textile structures also affects their properties The introduction of assistive materials, polyester and viscose, into the Shieldex (conductive yarn) structures is done to test core moisture management properties such as surface tension, absorption and moisture content, and correlate them to electrical properties necessary for textrode function. In the end the gap between textile structure and end product in form of a textrode is closed as the impedance and microclimate of the textrodes are studied. This is mainly to tie together the fundamental textile structures with a complex textile construction. In conclusion the complexity is also confirmed as structural, materialistic and external influences has an impact on the results. The influence of moisture on lowered resistance and impedance in the structures is confirmed but the impact of textile structure can also be seen. The 2-thread fleece and open structures often has a more positive impact on results and therefore has the possibility of enhancing performance of a textrode for bioelectrical signal monitoring. With these results a more effective way of producing long-lasting, patient-friendly, textrodes can be derived and in the future lead to better care in the medical areas.
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The Freezing Point of Water in Puddled and Unpuddled Soils at Different Soil Moisture Tension ValuesCampbell, Robert B. 01 May 1951 (has links)
A technique that will adequately describe the physical condition of water in the soil has long been desired by scientists. The method should include the effect of soluble materials on the osmotic pressure of the soil solution, and also the effect of surface force action between the soil and soil water.
Parker (8) demonstrated that the freezing point was reduced in the presence of finely divided material. This suggested the possibility of using the cryoscopic procedure to measure the physical condition of water soil. More recently, the introduction of Thermistors for accurate temperature measurement have made it desirable to investigate in greater detail the freezing point of water in soil.
The experimental work reported here deals with the freezing point of water in soil and its relation to soil moisture tension as determined on three soils in a puddled and unpuddled condition. Several freezing treatments were included in this study to investigate improvements in the freezing technique. The treatments were arranged in a standard split plot experimental design. Eighteen hundred freezing measurements were made and analyzed statistically.
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A Comparison of Soil Moisture and Hillslope-Stream Connectivity Between Aspen and Conifer-Dominated Hillslopes of a First Order Catchment in Northern UtahBurke, Amy R. 01 December 2009 (has links)
Mountain headwater catchments in the semi-arid Intermountain West are important sources of surface water because these high elevations receive more precipitation than neighboring lowlands. The hydrology of these mountain catchments is especially important as the region faces water shortages and conflicts. Conifer encroachment on aspen stands has been observed across the western US and can result in a decline in water yield. The overall objective of this study was to further our understanding of hillslope-stream connectivity in a headwater catchment of Northern Utah and any observable differences in this connection between aspen and conifer hillslopes. Hillslopes are the fundamental unit of a watershed. Therefore understanding processes at the hillslope scale is pertinent to managing valuable water resources. However, hillslope hydrology is understudied in the snow-driven, semi-arid west, leaving a gap in our knowledge of how watersheds function. This thesis focuses on how and when hillslope water contributes to stream water: hillslope-stream connectivity. Its specific objectives are (1) to compare peak snow accumulation under aspen and conifer stands, (2) to determine if shallow soil moisture shows organized patterns, indicating hillslope-connectivity and compare these patterns between vegetation types, (3) to examine hillslope-stream connectivity within deep layers of the soil profile and compare times of connectivity between vegetation types and (4) to find any thresholds past which hillslope-stream connectivity begins.
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Evalutation of the Effects of Reduced Transpiration Upon Soil Moisture in an Aspen Stand Throughout the Growing Season in Northern UtahZan, Michael 01 May 1968 (has links)
The direct effects of chemically- induced reduced transpiration on soil moisture were studied in a sub -watershed of the greater Logan River drainage.
No statistically significant differences occurred among the total amounts of water transpired by the treated and control units.
The seasonal low points of soil moisture, in September, showed no significant differences in final moisture retention for the two years studied, either for the control or the treated portions of the study site .
The 1967 season showed a lag in soil moisture depletion compared to the 1966 season. Although a later spring in 1967 may have aided in the explanation of this lag, there was good reason to believe that the antitranspirant treatment incurred a significant delay in water use.
There was evidence that more effective application of chemicals might have given more positive results.
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Seasonal, Diurnal and Species Variation in Forage Moisture Content in Relation to Site on Mountain Summer Range of Northern UtahSharif, Chaudhry Mohammad 01 May 1967 (has links)
Practical assessments of range production and utilization are based on forage weight estimates. In preparing these estimates moisture content in green vegetation offers some problems. The moisture component is not likely to be constant for a given species. Diurnal, seasonal and site variability have been well illustrated for agronomic and tree species (Salisbury, 1848; Jenkins, 1879; Miller, 1917; Pearson, 1924; Watkins, 1940; Parker, 1951; Ackley, 1954; Werner, 1954; Zohary and Orshan, 1956; Slatyer, 1959; Kozlowaki, 1965 and Jame son, 1966). Since variability is also likely for range plants, computations made on green weights are apt to be fallacious. It is a common practice, therefore, to express production on "water free" or "dry weight" basis. But the estimates of dry weight are made difficult by variations in herbage moisture. A variety of factors, relevant both to the vegetation and the site it occupies, would seem to account for variable moisture content. The prevalent methods for estimating moisture, however, seem to be more of a legacy from the past than an appreciation of ecological influences.
Earlier investigators of pastures and fodder crops were largely agronomists interested in comparing yields. They were concerned primarily with irrigated crops where soil moisture is not a limiting factor and the ecological influences, such as humidity, rain, cloudy weather, dew, shade, exposure etc. are far from dominant (Atwater, 1869; Collier, 1881; Richardson , 1884; Ladd, 1888; Richardson, 1889; Morse, 1891 and Widstoe, 1897). The variations in water content and other components were accordingly related to stage of growth. Taking a cue from these studies agencies such as the United States Forest Service and Soil Conservation Service came to use certain reducing factors to convert green weight of range forage into dry weight. In developing these factors the type of vegetation and growth phases have been considered but ecological features and context have been neglected. The methodology adopted from pasture conditions became the accepted basis for making range management decisions (Range Memo, SCS-8, Soil Conservation Service, 1963; Range Analysis, Region IV, Forest Service, 1964).
The influence of features of environment, particularly aspect, on growth differential, has long been recognized by foresters (Schlich, 1905; Champion, 1928 and Tourney, 1928). Plant physiologists have been aware of the significance of time-of-day on plant water for some time (Shreve, 1914; Miller, 1917). It is very probable that these influences express themselves in moisture content of herbage also.
The investigations reported herein were conducted to define and assess the scope and intensity of some of these ecological features in modification of the moisture component of herbage. The objective is to determine whether differences in ecological context influence range herbage moisture to a sufficient extent to warrant consideration in developing conversion factors for deriving dry weights from green weights of vegetation samples. The appraisal should reaffirm present assumptions applied or yield more accurate adjustments for estimating forage production. In either circumstance the results should enhance the scientific basis of range management decisions.
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On the Kinetics of Moisture Flow in Unsaturated SoilsBiggar, James Wellington 01 May 1956 (has links)
The flow of fluids in porous media continues to be a widely studied phenomenon. Soil moisture relationships and particularly the flow of water in soil is perhaps the most widely investigated of the four edaphatic factors related to plant growth, namely moisture, aeration, temperature and compaction.
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The Importance of Temperature Gradients on Soil Moisture Flowcavassa, Luigi 01 May 1953 (has links)
The isothermal movement of liquid water in saturated soil has been intensively studied, and a sound theoretical basis has been developed. Considerably less is known about the flow of water in unsaturated soils, but a general theory based on Darcy's law of flow is beginning to develop. A good theoretical basis exists for the vapor diffusion under isothermal conditions. Inconsistent data and theories are found in the literature concerning the movement of water in both the vapor and liquid phases, under the influence of thermal fields.
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Influence of Mountain Pine Beetle on Fuels, Foliar Fuel Moisture Content, and Litter and Volatile Terpenes in Whitebark PineToone, Chelsea 01 December 2013 (has links)
Mountain pine beetle (Dendroctonus ponderosae Hopkins) has caused extensive tree mortality in whitebark pine (Pinus albicaulis Engelm) forests. Previous studies conducted in various conifer forests have shown that fine surface fuels are significantly altered during a bark beetle outbreak. Bark beetle activity in conifer stands has also been shown to alter foliar fuel moisture content and chemistry over the course of the bark beetle rotation.The objective of this study was to evaluate changes to fine surface fuels, foliar fuel moisture and chemistry and litter chemistry in and under whitebark pine trees infested by mountain pine beetle. Fuels were measured beneath green (healthy) trees compared to red (two years since initial MPB attack with 50% or greater needles remaining) and gray (greater than two years since attack with between 15% and 45% needles remaining) trees. Foliar moisture content was measured in four mountain pine beetle crown condition classes: green-uninfested, green-infested (current year’s attack), yellow (last year’s attack), and red. Total terpene content was analyzed in whitebark pine needle litter and volatile terpenes were collected and analyzed from green, green-infested, yellow, and red trees.Significant differences were found in litter depths under green, red, and graytrees. Duff depths were significantly less beneath green trees than red and gray trees. One hour and ten hour fuels were more influenced by diameter and crown size than beetle crown condition classes. Foliar fuel moisture content dramatically decreased from green-infested to the red beetle crown condition class. No differences were detected in shrub and forb biomass between green, red, and gray trees. Green-infested trees had significantly lower foliar fuel moisture than green trees and by late in the season showed fuel moisture levels similar to red trees which had the lowest fuel moisture content. Litter beneath red trees contained large amounts of terpenes, including compounds known to increase foliage flammability that remain in the litter throughout the fire season. Total terpene content emitted from red foliage is greater than green-infested or yellow foliage.
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Effect of Short Duration Grazing on Soil Moisture Depletion and Plant Water Status in a Crested Wheatgrass PastureWraith, Jon M. 01 May 1986 (has links)
A short duration grazing system was utilized to determine the effects of intensive periodic defoliation during spring on soil moisture depletion patterns and plant water status in a crested wheatgrass (Agropvron cristatum and A. desertorum) pasture in central Utah. Exclosures were constructed to compare grazed and ungrazed responses. Soil moisture was monitored to a depth of 193 cm at one to two week intervals from mid-April to late-September using a neutron moisture gauge. Predawn and midday leaf water potentials were estimated using a pressure chamber technique. The two paddocks included in the study were grazed three times between mid-April and mid-June in 1985. A difference in time of grazing between the two paddocks was also examined for its effect on soil moisture depletion patterns and plant water status. Soil moisture was depleted at a higher rate within ungrazed plots than grazed plots during 13 April to 1 July in both paddocks. Soil moisture was depleted at a higher rate after 1 July in grazed compared to ungrazed plots in the early-grazed paddock; however, no difference in soil moisture depletion rate was noted after 1 July within the late-grazed paddock. Total cumulative depletion was greater within ungrazed plots than grazed plots in the early-grazed paddock from 6 June until 13 August, and from 23 May until 30 July in the late-grazed paddock. During the pre-July period, soil moisture was depleted more rapidly in the upper- and mid-portions of the soil profile in ungrazed plots. By 25 September there was no difference in total soil water depletion ' through 53 cm between grazed and ungrazed treatments, but ungrazed plots extracted relatively more water in the mid- and lower-portions of the soil profile. Grazing had no effect on predawn leaf water potentials prior to 1 July, but predawn leaf water potentials were lower for ungrazed plants than for grazed plants after 1 July. Midday leaf water potentials were lower for grazed plants than for ungrazed plants before 1 July, but did not differ between grazed and ungrazed plants after 1 July. Time of grazing had no effect on either predawn or midday leaf water potentials.
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Influence of Sodium Chloride, Calcium, Moisture, and pH on the Structure and Functionality of Nonfat Directly Acidified Mozzarella CheesePaulson, Brian M. 01 May 2004 (has links)
Experiment A explored the influence of sodium on direct acid, nonfat Mozzarella cheese. Cheeses with differing salt levels were obtained by varying dry salt applications (none, 0.5%, and 1.0% NaCl w/w) and hot brine stretching (0%, 5%, and 10% NaCl wt/v). Salt application and salt content influenced cheese moisture, meltability, expressible serum, micro- and ultra-structure, and color. Moisture was highest when cheese was salted before stretching (P = 0.03) . Melt was lowest in cheeses that were unsalted (P = 0.05). Cheeses stretched in salt brine had < 1% of the amount of expressible serum found in unsalted cheese (P < 0.0001). Unsalted cheeses had a more open structure with pockets of serum distributed throughout the protein matrix giving it an opaque, white appearance. Salted cheeses had a more homogeneous protein matrix lacking light scattering surfaces, resulting in a translucent cheese. Neither salt concentration nor method of salting affected the calcium content of the cheeses (P > 0.05).
Experiment B explored the influence of calcium, moisture, and pH on cheese structure and functionality. Cheeses were manufactured using combinations of citric and acetic acids. Addition of EDTA to the whey during cooking, CaCl2 fortification, and extended drain times were used to produce eight cheeses in a 23 factorial design with target pH levels of 5.8 and 5.3, 70% and 66% moisture, and 0.6% and 0.3% calcium levels. EDTA was unsuccessful in removing calcium from pH 5.8 cheese. Adding CaCh successfully increased the calcium level of pH 5.3 cheese. Cheese with 0.3% calcium had greatest melt, decreased hardness and increased adhesiveness. Cheese with 0.6% calcium had decreased melt and adhesiveness, and increased hardness. When calcium content was held at 0.6% there was no significant difference in melting even when pH was varied from pH 5.8 to pH 5.3 . The microstructure of the 0.6% calcium cheeses had an increase in protein folds and serum pockets. Low calcium cheeses had a very homogeneous structure.
Directly acidified nonfat Mozzarella cheese manufactured with 1.0% dry salt and hot water stretching produced the best cheese. This cheese contained 0.4% salt, 0.4% calcium, no expressible serum, and good meltability.
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