Canola meal was used as an adsorbent in a pressure swing adsorption (PSA) apparatus for ethanol dehydration. The experiments were conducted at different pressures, temperatures, vapor superficial velocities, vapor concentrations and particle sizes. Adsorption experiments were performed at equilibrium and breakthrough points. The results demonstrated that canola meal can break the azeotropic point 95.6 wt% and produce over 99 wt% ethanol. At elevated temperature, feed water concentration, and vapor superficial velocity, it was found that the mass transfer rate increased. In addition, the mass transfer rate decreases when either the total pressure or the size of the adsorbent particles are increased. Breakthrough curves were simulated and the overall mass transfer resistance was evaluated at all experimental runs. The internal mass transfer resistance was identified as the relevant mass transfer mechanism. For canola meal, the equilibrium water/ethanol uptake was achieved at 100, 105, and 110˚C. The Frenkel-Halsey-Hill (FHH) and Guggenheim-Andrson-de-Boer (GAB) models perfectly simulated the water adsorption isotherms. By applying Dubinin-Polanyi model to the experimental data, canola meal was identified as a large pore (non-porous) material. The heat of adsorption on canola meal with particle size of 0.43-1.18 mm was determined to be -32.11 kJ/mol. The result confirms that the adsorption process is an exothermic phenomenon and is of physical type due to the fact that the value obtained as the heat of adsorption is negative and its magnitude is within the range 20–80 kJ/mol. The equilibrium water uptake on canola meal was similar to that reported for other starchy and cellulosic adsorbents, while the ethanol uptake was higher. Water saturated canola meal was successfully regenerated by passing nitrogen at 110˚C which is lower than that for molecular sieves commonly used in industry for bioethanol dehydration. The canola meal bio-adsorbent was re-used for more than 32 cycles and no significant change in adsorption capacity was observed.

Exercise and/or heat-induced dehydration is associated with decreases in plasma volume (hypovolemia) and increases in plasma osmolality (hyperosmolality), which are thought to stimulate peripheral baroreceptors and central osmoreceptors respectively. Independently, plasma hyperosmolality and baroreceptor unloading have been shown to attenuate sweating and cutaneous vasodilation during heat stress, and therefore, negatively impact body temperature regulation. However, to date little is known regarding the combined influence of plasma hyperosmolality and baroreceptor unloading on thermoefferent activity. Therefore, we evaluated the separate and combined effects of baroreceptor unloading (via lower body negative pressure, LBNP) and plasma hyperosmolality (via infusion of 3% NaCl saline) on heat loss responses of sweating and cutaneous vascular conductance (CVC) during progressive whole-body heating. We show that the combined nonthermal influences of plasma hyperosmolality and baroreceptor unloading additively delay the onset threshold for CVC, relative to their independent effects. In contrast, baroreceptor unloading has no influence on the sweating response regardless of osmotic state. These divergent roles of plasma hyperosmolality and the baroreflex on heat loss responses might serve to enhance blood pressure and body core temperature regulation during dehydration and heat stress.

The study on dehydration of frozen saskatoon berries and the need for dried fruits have been strategically identified in the Canadian Prairies. The motivation for this research was to find a suitable method for dehydration and extend saskatoon berry shelf life for long term preservation. Microwave, convection and microwave-convection combination drying processes were identified to finish-dry saskatoon berries after osmotic dehydration, using sucrose and high fructose corn syrup (HFCS) sugar solutions. Osmotic dehydration removes moisture in small quantities introducing solutes into the fruit that acts as a preservative and also reduces the total drying time. <p>Due to the very short harvesting season of saskatoon berries, an accelerated process such as the microwave combination drying can reduce the moisture to safe storage levels immediately after harvest. Untreated and osmotically dehydrated berries were subjected to convection (control), microwave and microwave-convection combination drying conditions at different product drying temperatures (60, 70 and 80oC) until final moisture content was 25% dry basis. A laboratory-scale microwave combination dryer was developed with integrated temperature and moisture loss data acquisition systems using LabView 6i software. A thin-layer cross flow dryer was used for convection-only drying and for comparison. <p>Drying kinetics of the process were studied and curve fitting with five empirical equations, including the Page equation, was carried out to determine drying constant, R2 and standard error values. The microwave-combination drying method proved to be the best for drying saskatoon berries. Dehydrated product quality analyses were accomplished by measuring the color changes, rehydration ratio and any structural changes, using a scanning electron microscope technique.<p>This research was instrumental in the modification and development of a novel drying system for high-moisture agricultural materials (fruits). Microwave-convection combination drying at 70oC, yielded good results with higher drying rates and better end-product quality.

The magnocellular neurosecretory cells (MNCs) of the hypothalamus are responsible for the synthesis and secretion of vasopressin (VP), which is important for fluid homeostasis, and oxytocin (OT), which is responsible for uterine contraction during parturition and milk let-down during lactation. VP-ergic MNCs undergo a number of structural and functional changes during dehydration, including the adoption of a bursting pattern of firing, the retraction of glial processes from MNC somata and terminals, the translocation of kappa-opioid receptors from internal stores to the plasma membrane, and the somatodendritic release of VP and OT. Since voltage-gated Ca2+ channels have been found on intracellular granules, and since an increase in Ca2+ current could regulate firing patterns and neuropeptide release, the surface expression of Ca2+ channel subtypes in MNCs was tested to determine if it would be altered by 16-24 hours of water deprivation. Using radioligand binding of antagonists of N-type and L-type Ca2+ channels, channel density was measured in the supraoptic nucleus (SON), which is largely composed of MNC somata, and in the neurohypophysis (NH), which is largely composed of MNC terminals. Dehydration caused an increase in the density of L-type channels in the SON, while causing no significant change in the N-type density. No change in density of either channel type was observed in the NH. Electrophysiological measurements in isolated MNC somata showed no change in total Ca2+ current, but a significant increase in the nifedipine-sensitive current following dehydration. Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated no increase in messenger RNA levels for L-type channels, suggesting that the increase in channel density is not a consequence of de novo synthesis. These results suggest that L-type Ca2+ channels may be translocated from internal stores to the plasma membrane of MNCs in response to dehydration. Such a process may be important in maximizing secretion of VP when the physiological need is high.

Exercise and/or heat-induced dehydration is associated with decreases in plasma volume (hypovolemia) and increases in plasma osmolality (hyperosmolality), which are thought to stimulate peripheral baroreceptors and central osmoreceptors respectively. Independently, plasma hyperosmolality and baroreceptor unloading have been shown to attenuate sweating and cutaneous vasodilation during heat stress, and therefore, negatively impact body temperature regulation. However, to date little is known regarding the combined influence of plasma hyperosmolality and baroreceptor unloading on thermoefferent activity. Therefore, we evaluated the separate and combined effects of baroreceptor unloading (via lower body negative pressure, LBNP) and plasma hyperosmolality (via infusion of 3% NaCl saline) on heat loss responses of sweating and cutaneous vascular conductance (CVC) during progressive whole-body heating. We show that the combined nonthermal influences of plasma hyperosmolality and baroreceptor unloading additively delay the onset threshold for CVC, relative to their independent effects. In contrast, baroreceptor unloading has no influence on the sweating response regardless of osmotic state. These divergent roles of plasma hyperosmolality and the baroreflex on heat loss responses might serve to enhance blood pressure and body core temperature regulation during dehydration and heat stress.

The magnocellular neurosecretory cells (MNCs) of the hypothalamus are responsible for the synthesis and secretion of vasopressin (VP), which is important for fluid homeostasis, and oxytocin (OT), which is responsible for uterine contraction during parturition and milk let-down during lactation. VP-ergic MNCs undergo a number of structural and functional changes during dehydration, including the adoption of a bursting pattern of firing, the retraction of glial processes from MNC somata and terminals, the translocation of kappa-opioid receptors from internal stores to the plasma membrane, and the somatodendritic release of VP and OT. Since voltage-gated Ca2+ channels have been found on intracellular granules, and since an increase in Ca2+ current could regulate firing patterns and neuropeptide release, the surface expression of Ca2+ channel subtypes in MNCs was tested to determine if it would be altered by 16-24 hours of water deprivation. Using radioligand binding of antagonists of N-type and L-type Ca2+ channels, channel density was measured in the supraoptic nucleus (SON), which is largely composed of MNC somata, and in the neurohypophysis (NH), which is largely composed of MNC terminals. Dehydration caused an increase in the density of L-type channels in the SON, while causing no significant change in the N-type density. No change in density of either channel type was observed in the NH. Electrophysiological measurements in isolated MNC somata showed no change in total Ca2+ current, but a significant increase in the nifedipine-sensitive current following dehydration. Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated no increase in messenger RNA levels for L-type channels, suggesting that the increase in channel density is not a consequence of de novo synthesis. These results suggest that L-type Ca2+ channels may be translocated from internal stores to the plasma membrane of MNCs in response to dehydration. Such a process may be important in maximizing secretion of VP when the physiological need is high.

The study on dehydration of frozen saskatoon berries and the need for dried fruits have been strategically identified in the Canadian Prairies. The motivation for this research was to find a suitable method for dehydration and extend saskatoon berry shelf life for long term preservation. Microwave, convection and microwave-convection combination drying processes were identified to finish-dry saskatoon berries after osmotic dehydration, using sucrose and high fructose corn syrup (HFCS) sugar solutions. Osmotic dehydration removes moisture in small quantities introducing solutes into the fruit that acts as a preservative and also reduces the total drying time. <p>Due to the very short harvesting season of saskatoon berries, an accelerated process such as the microwave combination drying can reduce the moisture to safe storage levels immediately after harvest. Untreated and osmotically dehydrated berries were subjected to convection (control), microwave and microwave-convection combination drying conditions at different product drying temperatures (60, 70 and 80oC) until final moisture content was 25% dry basis. A laboratory-scale microwave combination dryer was developed with integrated temperature and moisture loss data acquisition systems using LabView 6i software. A thin-layer cross flow dryer was used for convection-only drying and for comparison. <p>Drying kinetics of the process were studied and curve fitting with five empirical equations, including the Page equation, was carried out to determine drying constant, R2 and standard error values. The microwave-combination drying method proved to be the best for drying saskatoon berries. Dehydrated product quality analyses were accomplished by measuring the color changes, rehydration ratio and any structural changes, using a scanning electron microscope technique.<p>This research was instrumental in the modification and development of a novel drying system for high-moisture agricultural materials (fruits). Microwave-convection combination drying at 70oC, yielded good results with higher drying rates and better end-product quality.

First generation bioethanol generated from feedstocks is a sustainable alternative to fossil fuels, and the demand for fuel ethanol has promoted studies on the use of the grain as feedstock. This thesis describes various process designs and the economic feasibility for producing the main product ethanol and other by-products such as Biogas and DDGS (Distillers Dried Grains with Solubles) from the grain. The techno-economic analysis was performed by the data provided by Agroetanol industry, located in Norrköping, Sweden. The key target of this simulation work was to evaluate the influence of several process designs and the main production factors on the ethanol production process, in terms of energy efficiency, ethanol production cost and plant profitability. The main aim of this work was to simulate the current industrial process and to develop novel alternative retrofits by integrating new technologies and for investigating the effects on the plant profitability. In the base case, the cost sensitivity analysis was carried out on the grain buying price, ethanol and DDGS selling price. Along with the cost sensitivity analysis, the capacity sensitivity analysis was performed on the base case model to check the influence of different capacities on the plant profitability. While coming to the study of developing alternative retrofits, the three retrofits were developed on the base case process and they are as following: Retrofit 1) modifying the distillation and dehydration section of the base case retrofit (current process in Agroetanol), Retrofit 2) checking the impact of ethanol concentration on technical and economic aspects of the plant and Retrofit 3) installing the biogas digester.The modelling effort resulted in developing the base case model with an ethanol production rate of 41,985 ton/ year. The capital cost of the base case process was calculated to be at 68.85 million USD and the aspen economic analyzer calculated the product value of the ethanol and DDGS as 0.87 USD/litre and 0.37 USD/kg, respectively. Through cost sensitivity analysis results, it is identified that the ethanol selling price and the grain buying price have significant effects on the plant economy and it is confirmed that they are the main factors playing on the plant profitability in the base case model.The results of the alternative retrofits clearly demonstrate the importance of higher ethanol tolerant strains in ethanol production, which showed a less payback period compared to the base case. The payback periods of all the cases are showing the following patterns from the least to the highest: Retrofit 2 (17%) &gt; Base case &gt; Retrofit 3 &gt; Retrofit 2 (4%) &gt; Retrofit 1.Further retrofitting analysis results also suggested that using the stillage for biogas production will help in reducing the energy costs of the plant. The energy consumption of all the retrofits in ascending manner is as follows: Retrofit 3 &gt; Retrofit 2 (17%) &gt; Base case &gt; Retrofit 1 &gt; Retrofit 2 (4%). The energy usage result comparison of all the cases shows that, in third retrofit the overall energy consumption is decreased by 40% than the base case model.

Exercise and/or heat-induced dehydration is associated with decreases in plasma volume (hypovolemia) and increases in plasma osmolality (hyperosmolality), which are thought to stimulate peripheral baroreceptors and central osmoreceptors respectively. Independently, plasma hyperosmolality and baroreceptor unloading have been shown to attenuate sweating and cutaneous vasodilation during heat stress, and therefore, negatively impact body temperature regulation. However, to date little is known regarding the combined influence of plasma hyperosmolality and baroreceptor unloading on thermoefferent activity. Therefore, we evaluated the separate and combined effects of baroreceptor unloading (via lower body negative pressure, LBNP) and plasma hyperosmolality (via infusion of 3% NaCl saline) on heat loss responses of sweating and cutaneous vascular conductance (CVC) during progressive whole-body heating. We show that the combined nonthermal influences of plasma hyperosmolality and baroreceptor unloading additively delay the onset threshold for CVC, relative to their independent effects. In contrast, baroreceptor unloading has no influence on the sweating response regardless of osmotic state. These divergent roles of plasma hyperosmolality and the baroreflex on heat loss responses might serve to enhance blood pressure and body core temperature regulation during dehydration and heat stress.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 199-211).