The colonias along the Texas-Mexico border are one of the most rapidly growing areas in Texas. Because of the relatively low income of the residents and an inadequate availability of transportation services, the need for basic social activities for the colonias cannot be properly met. The objectives of this study are to have a better comprehension of the status quo of these communities by examining the potential demand for an improved transportation service and evaluate the capacity and optimum service time interval of a new demand responsive transit "feeder" service within one representative colonia, El Cenizo. A comprehensive analysis of the results of a survey conducted through a questionnaire is presented to explain the existing travel patterns and potential demand for a feeder service. The results of this thesis and work from the subsequent simulation analysis showed that a single shuttle would be able to comfortably serve 150 passengers/day. It further showed that the optimal cycle length between consecutive departures from the terminal should be between 11-13 minutes for best service quality. This exploratory study should serve as a first step towards improving transportation services within these growing underprivileged communities especially those with demographics and geography similar to the target area of El Cenizo.

Previous studies on wood instability have identified some wood basic properties which influence the timber distortion and shape changes while the wood is losing or gaining moisture. These properties include wood anisotropic shrinkage, equilibrium moisture content (EMC) in both desorption and adsorption, fibre saturation point (FSP) and water diffusion coefficient. This study investigated the stability related wood properties and their variations within the stems of the New Zealand grown radiata pine trees. The basic density, EMC and shrinkage for the earlywood and the latewood were also experimentally determined. In taking into account these properties and their variations, an analytical model was developed to simulate the wood distortion. The equilibrium moisture content was determined at 30°C and humidity range from 27% to 90%. It was found that the EMC difference between the earlywood and the latewood was negligible. The experimental results also show that the EMC decreases from pith towards the bark over the disc cross section and the trend is most obvious at high humidities (70-90%). Along the tree height, the EMC decreases from ground towards the top of the stem. The tangential shrinkage results were highly variable but, in general, the latewood has higher values than the earlywood. The opposite trend was found for the longitudinal shrinkage, higher values for the earlywood than the latewood. In the tree height direction, the tangential shrinkage was found to decrease with the tree height. This follows the same trend as the microfibril angle which in general also decreases with the tree height. The fibre saturation point (FSP) was determined from the tangential shrinkage values at different equilibrium moisture contents. These were taken as the intersection point of the tangential shrinkage line with the moisture content axis. The experimental results have revealed a trend that the FSP decreases from the pith towards the bark and also decreases with the tree height. Similar behaviour was found for the tangential and longitudinal swelling during the adsorption. The moisture transport within radiata pine was investigated based on the diffusion theory under transient and isothermal condition of 30°C. The moisture dependant diffusion coefficient was derived from the experimental data using the inverse analysis method. The surface emission coefficient was determined by taking into account the variable surface moisture content, wood density and the ambient conditions. In the experiments, 138 samples in total (46 samples for each XIV of the longitudinal, tangential and radial directions) were used and their diffusion coefficients were determined for both the adsorption and the desorption with moisture content ranging from 6% to 22%. The derived diffusion coefficients are comparable with the reported data in the literature. Further investigation of the wood type influence on the diffusion coefficient revealed that compression wood has the lowest diffusion coefficients in the three directions (longitudinal, tangential and radial) both in the desorption and in the adsorption. In addition, the moisture content has the least influence on the diffusion coefficient in the compression wood. Investigation on the effects of the wood density has shown that in general, the diffusion coefficient decreases with increasing wood density although the correlations are only significant for the longitudinal direction in desorption. An analytical model for the simulation of the wood twist was developed which is based on the geometry and geometrical changes of the grains aligning non parallel to the pith. A board consists of numerous such grains which change the length and shape with moisture content change. The model predictions confirm that the grain angle, the tangential and longitudinal shrinkage and the conical angle all affect the development of the board twist. However, the discrepancies between the model prediction and the experimental data are significant, partly due to the experimental uncertainties and partly due to the model errors. In this study, sound velocity in the longitudinal direction was measured for the test samples used in the shrinkage experiments. The results revealed that the correlations between the sound velocity and the volumetric shrinkage at oven dry are significant. Based on this finding, the relationship between the tangential shrinkage and the radial shrinkage, the tangential shrinkage can be predicted from the sound velocity measurements. As the tangential shrinkage has significant influence on the wood distortion, this method can be used to segregate logs which may be prone to wood distortion.

Les objectifs principaux des travaux de recherche réalisés sont de caractériser, quantifier et corréler les changements induits lors du recyclage sur les fibres, la pâte et le papier. Pour ce faire, des techniques de caractérisation spécifique ont été utilisées telles que la chromatographie inverse d'exclusion stérique (ISEC), l'analyse mécanique dynamique (DMA), la microscopie électronique à balayage environnementale (ESEM), la microscopie à force atomique (AFM) et la tomographie à rayons X. Le racornissement des fibres à elle seule ne peut pas expliquer totalement la perte de résistance des fibres. Lors du recyclage la largeur des fibres, l'épaisseur des parois fibreuses, la courbure, le nombre de coudes et d'irrégularité diminuent. Les points faibles à l'intérieur de la paroi augmentent dans les premiers et les derniers cycles de recyclage. Les fibres deviennent plus dures et cassantes à l'état sec. Les forces capillaires et la friction de surface augmentent à l'état humide. La surface de liaison entre fibres dans le réseau fibreux diminue initialement à cause de la perte de la flexibilité des fibres à l'état humide et des éléments fins alors que l'augmentation qui suit peut être reliée au collapse du lumen. Comme la solidité des fibres de diminue pas, la baisse des caractéristiques mécaniques du papier pourrait être attribuée à la dégradation de la qualité des liaisons et plus particulièrement à une délamination partielle de la couche P/S1. / Incorporation of recycled fibres in high value paper products can reduce costand environmental loads. Papermaking potential of cellulosic fibres decreaseswith recycling. The phenomenon of fibre hornification during pressing anddrying is normally held responsible for the loss in strength. To study the impactsof recycling on pulp, fibre and paper properties some non conventionalcharacterisation techniques like fibre saturation point, X-rays microtomography,environmental scanning electron microscopic observations, atomic forcemicroscope (PeakForce QNM mode) and inverse size exclusion chromatography(ISEC) were used. In order to achieve good reproducibility of ISEC measurements,a semi-automatic column fabrication pilot system was built. Thetechniques were first validated on refining process before being applied to therecycling process. In this study, it was found that fibre hornification alone cannot fully explain loss in strength during recycling. The loss in strength is muchmore complex and it is required to understand the morphological and ultrastructural changes associated with recycling. Fibre width, cell wall thickness,curl, kink, irregularities decreased during recycling. Fibre became hard andbrittle in dry state. Number of weak points in the fibre wall were increasedinitially and in the later recyclings. The increase in wet breaking length indicatesincreased surface friction and capillary forces with recycling. Decreasein bonded area during first recycle may be caused by the loss of fines and fibreflexibility whereas the increase afterwards may be linked to the lumen collapse.The strength of fibres did not decrease with recycling as shown by zero-spanbreaking lengths therefore the quality of bond may be deteriorated. It wasthought that the partially delaminated P/S1 layers may be responsible for theloss of paper strength. It is suggested since the significant change is associatedwith the pressing and drying of never dried pulp therefore the drying processneeds to be revisited. The delaminated layer should be restored so as to increasethe recyclability of the recovered fibres for high value paper. Influenceof recycled pulp blends on physical properties of paper was also studied. It wasrevealed that small quantity of recycled pulp can be used without significantlyaffecting the mechanical strength properties.

From the Proceedings of the 1973 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 4-5, 1973, Tucson, Arizona / Measurements of penetrability and hydraulic conductivity in calcareous soils treated with a dilute sulfuric acid solution showed a severe decrease in conductivity with increasing concentrations over 1000 ppm. A slight decrease in penetrability was observed. Carbon dioxide evolution appeared to be responsible for flow reduction and temporary cessation at 10,000 ppm and 20,000 ppm. In sodic soils penetrability and conductivity increased markedly with sulfuric acid concentrations between 1,000 and 10,000 ppm. For a neutral soil, penetrability decreased with increasing sulfuric acid concentrations, and the stable conductivity for 500 to 5,000 ppm was higher than for water alone. The findings suggest that disposal of sulfuric acid concentrations greater than 1,000 ppm will result in plugging by carbon dioxide. In sodic soils the possibility exists of using sulfuric acid solutions for reclaiming salt and sodium-affected soils.

This paper deals with the determination of the capillary pore-size distribution (CPSD) and equilibrium moisture content (EMC) of untreated and thermally modified (TM) Norway spruce [Picea abies (L.) Karst.] by means of the pressure plate technique (PPT). Desorption experiments were conducted at very high values of relative humidity (RH) in the range between 99.2% and 100%. The thermal modification of spruce results in an alteration of the CPSD, owing to the formation of intercellular cracks in the middle lamella, as a result of cell-wall compression. The desorption curves for both untreated and TM spruce show an extremely upward bend at 99.97% RH. This step reflects an EMC of 38.1% for untreated spruce and 33.8% for TM spruce. None of the samples shrunk during the PPT measurements. Following desorption experiments at 97.4% RH, all samples shrunk. This step reflects an EMC of 27.9% for untreated spruce and 21.7% for TM spruce.