Pulsed electric field (PEF) technology applied to food processing was firstly used in the late 1960s. The currently available systems use either conventional Blumlein generators or generators similar to those found in radar power sources to produce the required high voltage pulses. The liquid to be processed is passed through a number of treatment chambers or cells which each contain a pair of electrodes in contact with the liquid. An electric field is thereby applied to the liquid, leading to the technology being termed invasive and it can be used only with liquid food. A novel and non-invasive PEF technology for use in the food processing industry is introduced and investigated in this thesis. The technology represents a novel way of performing PEF treatment. A proof of concept arrangement uses two ceramic cylinders mounted inside the non-invasive PEF cell with a gap of 3 mm between them. A displacement current of the order of mA passes through the non-invasive PEF cell during treatment, as compared with the kA of current usually produced during an invasive treatment. The low current is not only economic in electric energy but also maintains a low food temperature, which implicitly maintains food flavour. In the thesis the electro-optic Kerr effect technique is used to perform accurately the PEF measurement and convincingly prove that strong electric fields are present. Two Kerr water cells were designed and used to determine the Kerr constant for water, since the data presented in the literature is unreliable. The first Kerr water cell uses a pair of Bruce profile stainless steel electrodes and the second a pair of parallel plate stainless steel electrodes. An electro-static solver (Maxwell software) was used to determine the electric field distribution and to calculate the electric field integral to accurately determine the Kerr constant for water. Water samples containing the E-coli bacteria were prepared and filled in the non-invasive PEF cell by the Flavometrix Company. Eight PEF experiments were successfully performed during this research programme and the results show unequivocally that the novel noninvasive technique is effective in significantly reducing the initial concentration of E-coli bacteria. This opens the door for the future design of an industrial prototype.

Lowland riparian ecosystems constitute a tiny fraction of total land area in the southwestern United States and northern Mexico, yet they are extremely important to human livelihoods and biotic communities. Facing ongoing projected climate change toward hotter and drier conditions, riparian ecosystems are both vulnerable to changes in climate and increasingly critical to the well-being of humans and wildlife. Due to the dynamic nature of these ecosystems and their abundance of resources, riparian areas have been modified in various ways and to a large extent through human endeavor. These alterations often interfere with multiple and complex ecological processes, making riparian areas more vulnerable to disturbance and change. Few naturally functioning riparian areas remain, and those that do are imperiled by climate change, groundwater pumping, land use, and other factors. A small but growing body of literature suggests that wildfires may be increasing in frequency and severity in southwestern riparian zones. This literature review summarizes and synthesizes the state of the knowledge of wildfire and prescribed fire effects on abiotic processes and vegetation, and post-fire rehabilitation. Results suggest that in lowland riparian ecosystems, fire regimes and fire effects are influenced primarily by streamflow and groundwater regimes. Thus, increasing fire frequency and severity may be attributed to drought, land use, water use, and their subsequent effects on the spread of non-native plant species, as well as a history of fire suppression and increasing anthropogenic ignitions in areas with a growing human presence. Changing fire regimes are likely to have drastic and potentially irreversible effects on regional biodiversity and ecosystem function. However, there are options for managing riparian ecosystems that will be more resilient to fire and climate change, such as implementing environmental flows, prescribed fire, fuel reduction treatments, floodplain restoration, and promoting gene flow. This study is intended to inform management decisions, and identify gaps in systematically reviewed literature.

Invasive alien tree species have negative environmental and economic impacts throughout the world. For example, black wattle (Acacia mearnsii) threatens native habitats by competing with and so repressing or excluding indigenous vegetation: in this way it replaces grass communities, reduces biodiversity, and increases water loss from riparian zones, thereby fundamentally damaging the ecosystem. The Acacia mearnsii threat requires urgent attention: effective control and management is urgently required if these deleterious impacts are to be reversed or prevented. The present study was conducted in the Elliot and Ugie communities situated in the Sakhisizwe and Elundini Local Municipalities. The objective of this study was to design integrated, efficient and cost-effective methods to help farmers and members of these communities with control and management of alien plant invasions. Further the study aimed to evaluate the implementation and efficacy of Working for Water (WfW) initiatives in poverty alleviation, and skills development: in addition the study attempted to assess WfW inputs as regards relevant legislation aimed at combating major wattle invasions. Mixed methodological approaches were employed, utilizing both qualitative and quantitative techniques. Questionnaire surveys, semi-structured interviews, use of photos, content analyses of local documents and experimental field work were all employed in order to collect and interpret data for the study. The study reveals that mechanical control and rehabilitation in combating should provide efficient and cost-effective methods for proper management of rangelands. Moreover the National Department of Agriculture, Forestry and Fisheries (DAFF) should be urged to devise and enforce legislation that will help to ensure sustainable control and management of black wattle through conservation of the natural environment. Furthermore funds should be made available for wattle eradication programmes so as alleviate poverty by creating more job opportunities for members of poor communities.

To date, 13168 plant species have been naturalized outside their native range. While invasive plants efficiently compete for resources, they can also disrupt vital mutualisms. Pollination is a crucial mutualism required for 87% of flowering plants to reproduce. Invasive species may disrupt patterns of pollinator visitation, pollen transfer dynamics (conspecific [CP] and heterospecific [HP]), and reproductive success. Furthermore, whether invasive species’ effects depend on scale (site vs. patch) is not known. Thus, it is critical to understand the effects of invasive plants at all stages of pollination and how those effects vary with scale. Here, I investigate pollinator visitation, CP and HP deposition, and pollen tube growth between local flowers in sites and plots invaded by Cirsium arvense. For 7 weeks (June-July), pollinator visits were recorded and styles collected from an invaded and non-invaded floral community. Styles were processed for fluorescent microscopy. The number and identity of pollen grains on stigmas and the number of pollen tubes at style bases were recorded. The invaded site received significantly less visits than the non-invaded site, but the effect varied by species. This variation is not explained by local species’ abundance or floral symmetry. Similarly, invaded plots received significantly less visits than non-invaded plots, and no plot-species interaction was found. The invaded site received more CP and HP while invaded plots received less CP and HP. There was no difference in pollen tube growth between sites or plots. My preliminary results suggest that C. arvense affects pollinator visitation and pollen transfer dynamics in local floral communities, but the effects vary depending on species and scale. Conversely, these effects do not seem to lead to differential reproductive success between invaded and non-invaded communities at any scale.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22480号 / 農博第2384号 / 新制||農||1075(附属図書館) / 学位論文||R2||N5260(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 吉村 剛, 教授 井鷺 裕司, 講師 YANG Chin-Cheng / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Tel Aviv is a rapidly changing city. Since its establishment only a century ago, the city has developed into an innovation hub, rich with culture and architectural history. Part of its hasty evolution from the land of sand dunes to the current metropolis was the construction of the Tel Aviv New Central Bus Station, the largest bus station in the world at the time of completion. Almost three decades after Israeli Architect Ram Karmi designed the station, it opened in 1993, already nicknamed the “white elephant” due to its scale and lack of integration into the surrounding neighborhood of Neve Sha’anan. The New Central Bus Station never met the architect’s intended vision of “a city under a roof” and has significantly transformed over the years, as an attempt to create purpose within the large mass. Neve Sha’anan, in south Tel Aviv, is the poorest area of the city, ridden with homelessness, prostitution and drug addiction. It is also the home to the majority of the African refugee and asylum seeker community i Israel, making up less than half a percent of the population of the country. The small community has been the target of recent refugee policy reforms, which frame them as “infiltrators” or “labor migrants.” 1 The New Central Bus Station fractures the urban environment of Neve Sha’anan and causes spatial disorientation of a community already faced with cultural marginalization. Through an analysis of the impact that top down decision making causing cultural conflict has on architecture and place making, this thesis sets to develop a solution for intervention, which considers the users and urban context as a source for re-configuring existing infrastructure. / 0 / SPK / specialcollections@tulane.edu

Spinal cord injury (SCI) leads to axonal damage and limits the ability of the brain to communicate with the rest of the body. Several bioengineered approaches have been developed for the recovery of SCI. Among these techniques, degradable guidance tubes have shown promising results. However, design of nerve guide tubes requires several design considerations and has been a significant challenge. To assess the efficacy of a prototypical implanted nerve guide tubes, it is essential to perform continuous monitoring. In this respect, magnetic resonance imaging (MRI) is one of the most reliable imaging techniques as it offers the ability to achieve extraordinary high temporal and spatial resolution in addition to its non-invasive features. In spite of the excellent image quality of non-enhanced MRI various types of contrast agents have been developed to further enhance the contrast and allow improved visualization. The MRI contrast agents principally work by shortening the T1 or T2 relaxation times of protons located nearby. The presented study was intended to evaluate the in vitro degradation of the nerve guide tubes made of poly (lactic-co-glycolic acid) (PLGA). PLGA tubes incorporated with different concentrations of superparamagnetic iron oxide (SPIO) were scanned by MRI 3T on weekly basis during the degradation period. Spin-echo (SE) sequence with various echo times (TEs) ranged from 13.3 to 314.4 msec was applied. T2 mapping was computed using in-house algorithm developed in Matlab. Least square fit was used to find the slope of the decay curve by plotting log intensity on the y-axis and echo time on the x-axis. The average T2 values were calculated. Mass loss and water uptake of the degrading tubes were also measured weekly. Moreover, the micro-structural changes of the tubes were investigated using the scanning electron microscope (SEM). The MRI results showed that the concentration of SPIO affects the signal intensity of the T2 weighted images reducing the T2 relaxation time value. Accordingly, a linear correlation between SPIO concentration and T2 relaxation time was found. At the beginning of degradation, the SPIO nanoparticles were trapped within the polymeric network. Therefore, water penetration was the predominant factor affecting the T2 relaxation times. At week 5, a significant mass loss was observed. From this stage onwards, the trapped SPIO were released from the polymeric network increasing T2 relaxation time dramatically. According to SEM images, the size of the pores in PLGA guide tubes was increased with the degradation. Approaching the end of degradation, shrinkage of the tubes was observed and the degraded nerve guide tubes were shown to be collapsed. Similar shape variation was observed in T2 weighted MR images. In summary, this study provided an approach to non-invasive monitoring of degradation behavior of nerve guide tubes using contrast enhancement. The developed technique is of great importance since it opened an insight to non-invasive monitoring of tissue engineered scaffolds for in vivo studies.

Indiana University-Purdue University Indianapolis (IUPUI) / This research focuses on the detection of arterial blockage due to LDL (low density lipoprotein). Arterial blockages are related to two kinds of fats LDL and the HDL. HDL being the good fat, the patient does not have to undergo the biopsy, while in case of LDL, biopsy should be performed. Issues associated with invasive approaches raise safety concerns for patients such as infection, longer operation durations, longer recovery time etc. This research focuses on a noninvasive imaging technique to detect the kind of block age. Photo acoustic approach was investigated in order to simulate human tissues leading to medical diagnosis and treatment. Photo acoustic imaging involves production of an image on absorption of laser pulses. The laser pulses are further scattered and absorbed producing heat. The goals of the study were to categorize the type of the tissue materials based on the output temperature distribution via IR sensors and reflected acoustic waves via acoustic pressure sensors. The reflected acoustic wave and IR thermal distribution may be applied towards arterial blockages to differentiate the different types of tissue layers. The simulation results should have implications towards the future implementation of the practical devices and system. Parameters including energy levels, tissue thicknesses, frequencies, penetration depth, and the densities of the LDL/HDL fat materials were considered. Various energy pulses; 1j, 3j, and 5j were considered as input sources to the tissue materials (single or multi layers). The simulated layers considered in the study were the skin, bone, blood, and fat cells. The temperature and acoustic pressure response over the various layers were analyzed for the detection of blockages. The ndings of the temperature and acoustic pressure ranges can be detected by MEMS/NEMS (Micro electro mechanical systems/ nano electro mechanical systems) sensors, such as IR and Piezoelectric devices. Bioheat and acoustic wave equations were solved simultaneously using COMSOL software for multiple layers. The proper boundary conditions were provided in the solutions of these equations. The scattering and transmission acoustic wave, and the temperature distributions, may be used as guide to the integrated sensor system design for future consideration. The simulation was performed in four stages: (1) Single layer and multiple layers at a given frequency and energy level (2) Multiple layers at a given frequency for different energy levels (3) Multiple layers at a given energy level for different frequency and (4) Multiple layers at a given frequency and energy levels with different size tissues. The simulation results showed that a range of acoustic pressure between 240 and 260 need to be detected, with a di erential temperature distribution in kelvin range. Power pulses of 10MPa showed a temperature change of 175, which is believed to be within the exible substrate sensing devices that may be used for the practical model of this research. The thesis covers a proposed system for the practical model following the simulation results received in this study.

No description available.

Studies conducted to determine life history and starch allocation of common reed (Phragmites australis), and evaluate haplotype susceptibility to aquatic labeled herbicides. Twelve 0.1 m2 samples were taken from four sites in the Mobile River delta from January 2006 to December 2007. Samples separated into above and belowground biomass dried and weighed. Starch determination used the amylase/amyloglucosidase method. Biomass decreased with decreasing temperature. Aboveground biomass was 2200 and 1302 g m2 in October 2006 and December 2007. Belowground biomass was 1602 and 1610 g m-2 in November 2006 and December 2007. Aboveground starch was highest in December of 2006 and November of 2007. Belowground starch peaked in August of 2006 and September of 2007. RFLP methodologies were used to identify populations of I and M used for herbicide sensitivity screening. No difference detected in the susceptibility of haplotypes. Glyphosate, imazapyr, and triclopyr are effective herbicides for common reed control.