Hydro-physical characterization of media used in agricultural systems to develop the best management practices for operation of an environmentally sustainable agricultural enterprise

Florida is the second leading horticulture state in the United States with a total annual industry sale of over $12 Billion. Due to its competitive nature, agricultural plant production represents an extremely intensive practice with large amounts of water and fertilizer usage. Agrochemical and water management are vital for efficient functioning of any agricultural enterprise, and the subsequent nutrient loading from such agricultural practices has been a concern for environmentalists. A thorough understanding of the agrochemical and the soil amendments used in these agricultural systems is of special interest as contamination of soils can cause surface and groundwater pollution leading to ecosystem toxicity. The presence of fragile ecosystems such as the Everglades, Biscayne Bay and Big Cypress near enterprises that use such agricultural systems makes the whole issue even more imminent. Although significant research has been conducted with soils and soil mix, there is no acceptable method for determining the hydraulic properties of mixtures that have been subjected to organic and inorganic soil amendments. Hydro-physical characterization of such mixtures can facilitate the understanding of water retention and permeation characteristics of the commonly used mix which can further allow modeling of soil water interactions. The objective of this study was to characterize some of the locally and commercially available plant growth mixtures for their hydro-physical properties and develop mathematical models to correlate these acquired basic properties to the hydraulic conductivity of the mixture. The objective was also to model the response patterns of soil amendments present in those mixtures to different water and fertilizer use scenarios using the characterized hydro-physical properties with the help of Everglades-Agro-Hydrology Model. The presence of organic amendments helps the mixtures retain more water while the inorganic amendments tend to adsorb more nutrients due to their high surface area. The results of these types of characterization can provide a scientific basis for understanding the non-point source water pollution from horticulture production systems and assist in the development of the best management practices for the operation of environmentally sustainable agricultural enterprise

A study of branching fluid networks for enhancing the performance of thermal -fluid devices

Compact thermal-fluid systems are found in many industries from aerospace to microelectronics where a combination of small size, light weight, and high surface area to volume ratio fluid networks are necessary. These devices are typically designed with fluid networks consisting of many small parallel channels that effectively pack a large amount of heat transfer surface area in a very small volume but do so at the cost of increased pumping power requirements. ^ To offset this cost the use of a branching fluid network for the distribution of coolant within a heat sink is investigated. The goal of the branch design technique is to minimize the entropy generation associated with the combination of viscous dissipation and convection heat transfer experienced by the coolant in the heat sink while maintaining compact high heat transfer surface area to volume ratios. ^ The derivation of Murray's Law, originally developed to predict the geometry of physiological transport systems, is extended to heat sink designs which minimze entropy generation. Two heat sink designs at different scales are built, and tested experimentally and analytically. The first uses this new derivation of Murray's Law. The second uses a combination of Murray's Law and Constructal Theory. The results of the experiments were used to verify the analytical and numerical models. These models were then used to compare the performance of the heat sink with other compact high performance heat sink designs. The results showed that the techniques used to design branching fluid networks significantly improves the performance of active heat sinks. The design experience gained was then used to develop a set of geometric relations which optimize the heat transfer to pumping power ratio of a single cooling channel element. Each element can be connected together using a set of derived geometric guidelines which govern branch diameters and angles. The methodology can be used to design branching fluid networks which can fit any geometry. ^

Hydro-Physical Characterization of Media Used in Agricultural Systems to Develop the Best Management Practices for operation of an Environmentally Sustainable Agricultural Enterprise

Florida is the second leading horticulture state in the United States with a total annual industry sale of over $12 Billion. Due to its competitive nature, agricultural plant production represents an extremely intensive practice with large amounts of water and fertilizer usage. Agrochemical and water management are vital for efficient functioning of any agricultural enterprise, and the subsequent nutrient loading from such agricultural practices has been a concern for environmentalists. A thorough understanding of the agrochemical and the soil amendments used in these agricultural systems is of special interest as contamination of soils can cause surface and groundwater pollution leading to ecosystem toxicity. The presence of fragile ecosystems such as the Everglades, Biscayne Bay and Big Cypress near enterprises that use such agricultural systems makes the whole issue even more imminent. Although significant research has been conducted with soils and soil mix, there is no acceptable method for determining the hydraulic properties of mixtures that have been subjected to organic and inorganic soil amendments. Hydro-physical characterization of such mixtures can facilitate the understanding of water retention and permeation characteristics of the commonly used mix which can further allow modeling of soil water interactions. The objective of this study was to characterize some of the locally and commercially available plant growth mixtures for their hydro-physical properties and develop mathematical models to correlate these acquired basic properties to the hydraulic conductivity of the mixture. The objective was also to model the response patterns of soil amendments present in those mixtures to different water and fertilizer use scenarios using the characterized hydro-physical properties with the help of Everglades-Agro-Hydrology Model. The presence of organic amendments helps the mixtures retain more water while the inorganic amendments tend to adsorb more nutrients due to their high surface area. The results of these types of characterization can provide a scientific basis for understanding the non-point source water pollution from horticulture production systems and assist in the development of the best management practices for the operation of environmentally sustainable agricultural enterprise

New fuel cells system for portable application with low temperature cofired ceramic (LTCC) technology

Miniature direct methanol fuel cells (DMFCs) are promising micro power sources for portable appliction. Low temperature cofired ceramic (LTCC), a competitive technology for current MEMS based fabrication, provides cost-effective mass manufacturing route for miniature DMFCs. Porous silver tape is adapted as electrodes to replace the traditional porous carbon electrodes due to its compatibility to LTCC processing and other electrochemical advantages. Electrochemical evaluation of silver under DMFCs operating conditions demonstrated that silver is a good electrode for DMFCs because of its reasonable corrosion resistance, low passivating current, and enhanced catalytic effect. Two catalyst loading methods (cofiring and postfiring) of the platinum and ruthenium catalysts are evaluated for LTCC based processing. The electrochemical analysis exhibits that the cofired path out-performs the postfiring path both at the anode and cathode. The reason is the formation of high surface area precipitated whiskers. Self-constraint sintering is utilized to overcome the difficulties of the large difference of coefficient of thermal expansion (CTE) between silver and LTCC (Dupont 951) tape during cofiring. The graphite sheet employed as a cavity fugitive insert guarantees cavity dimension conservation. Finally, performance of the membrane electrode assembly (MEA) with the porous silver electrode in the regular graphite electrode based cell and the integrated cofired cell is measured under passive fuel feeding condition. The MEA of the regular cell performs better as the electrode porosity and temperature increased. The power density of 10 mWcm-2 was obtained at ambient conditions with 1M methanol and it increased to 16 mWcm -2 at 50°C from an open circuit voltage of 0.58V. For the integrated prototype cell, the best performance, which depends on the balance methanol crossover and mass transfer at different temperatures and methanol concentrations, reaches 1.13 mWcm-2 at 2M methanol solution at ambient pressure. The porous media pore structure increases the methanol crossover resistance. As temperature increased to 60°C, the device increases to 2.14 mWcm-2.

Identity as a moderator of guided -self change treatment outcomes with adolescents

Despite recent calls to examine the possible moderating effects of developmental variables on treatment outcomes with adolescents, most research has continued to focus on age as a main developmental variable. Building upon the theoretical notion that identity development is a central task of adolescence, this study investigated whether adolescents' response to an alcohol and other drug (AOD) use reduction intervention, Guided-Self Change (GSC), was influenced by their approach to self-defining questions and situations. While past research has established associations between maladaptive identity development and alcohol and other drug use, very little research attention has been given to the potential relationship that may exist between identity variables and AOD treatment response. Given GCS's promotion of self-reflective, self-exploring, and problem-focused coping skills as a way of addressing AOD problems, it was hypothesized that adolescents with positive identity development (i.e., greater identity coherence and adaptive identity processing styles) would respond more positively to GCS's change producing therapeutic techniques than their counterparts. This hypothesis was tested with an ethnically diverse sample of 134 adolescents between the ages of 14-18 years who were randomly assigned to either a GSC intervention or a comparison control group. Results revealed that identity development was significantly associated with AOD use, such that adolescents with diffused/avoidant styles and high levels of distress over identity-related issues used more alcohol at the baseline assessment than those with more positive identity development. Results also indicated that while identity distress or identity coherence did not moderate GSC treatment outcomes, high scores for a diffused/avoidant style did moderate treatment outcomes and thus proved to be a significant predictor of treatment response. These results indicate that identity development influences adolescents' alcohol use and that while use of certain approaches to self-defining questions does not predict treatment outcomes, high use for negative approaches does moderate intervention-related change. ^

Exploring the Use of Everglades Agricultural Area Canal Water as Base Medium for the Mass Production of Algae for Biofuels

Freshwater use is a major concern in the mass production of algae for biofuels. This project examined the use of canal water obtained from the Everglades Agricultural Area as a base medium for the mass production of algae. This water is not suitable for human consumption, and it is currently used for crop irrigation. A variety of canals were found to be suitable for water collection. Comparison of two methods for algal production showed no significant difference in biomass accumulation. It was discovered that synthetic reticulated foam can be used for algal biomass collection and harvest, and there is potential for its application in large-scale operations. Finally, it was determined that high alkaline conditions may help limit contaminants and competing organisms in growing algae cultures.

Education and training in the use of physical agent modalities by occupational therapists practicing in the physical disabilities area

This study was conducted to examine how occupational therapists (OTs) practicing in the physical disabilities area received their training in the use of physical agent modalities (PAMs); to determine the frequency of PAMs usage by those therapists; and to obtain their opinions regarding the training of OTs and OT students in the administration of PAMs. Three hundred OTs practicing in physical diabilities (n = 194 returned) were surveyed. The most frequently used modalities were hot and cold packs, paraffin, and ultrasound. The least frequently used modalities were transcutaneous electrical stimulation (TENS) and whirlpool. On-the-job training was the most common educational method received by the respondents for PAMs usage. The respondents considered a combination of undergraduate education, fieldwork, continuing education and on-the-job training as the most appropriate educational setting for training in modalities. While few of the respondents received preparation in PAMs during entry-level academic programs, the majority felt that OT students should be trained in PAMs usage as part of their education curriculum. ^

The use of the Dade County student assistance profile in the identification of at -risk students at a minority senior high school

Current high school completion rates in Dade County and across the nation are considered to be unacceptable. This has led to the development of student assistance profiles to aid in the early identification of students considered to be at risk to allow for some form of intervention. The purpose of this research was to examine the current Dade County Public Schools profile as applied to one specific high school in which most of the students are Hispanic (mostly of Mexican descent) and Black (African-Americans, as well as recent Haitian immigrants). Additionally, the effectiveness of the alternative intervention program provided at this high school--a school within a school--were evaluated. School records of the 1992 in-coming ninth grade class became the initial data base. The individual student records of this cohort were then examined over a four-year period until their expected date or graduation. The DCPS profile used to identify potential dropouts from this group was evaluated, using chi-square and multivariate analysis, to determine its overall effectiveness, as well as the effectiveness of the individual indicators which comprise the profile. The Student Assistance Profile was found to an effective predictor, but it over-identified students from this cohort, particularly minorities, to the extent that it became largely ineffective, especially considering the limited resources available for intervention. The intervention program was found to be ineffective in reducing the dropout rate. Further analysis of the individual indicators used in the DCPS profile as they applied to this school population resulted in the development of an improved profile. By reducing the number of indicators to those found to be most highly associated with failure to graduate--academic performance and absences--a simpler student assistance profile was developed which appears to be better suited to high schools with similar demographics and budget restraints. ^

Evaluating High-Resolution Aerial Photography Acquired by Unmanned Aerial Systems for Use in Mapping Everglades Wetland Plant Associations

Mapping of vegetation patterns over large extents using remote sensing methods requires field sample collections for two different purposes: (1) the establishment of plant association classification systems from samples of relative abundance estimates; and (2) training for supervised image classification and accuracy assessment of satellite data derived maps. One challenge for both procedures is the establishment of confidence in results and the analysis across multiple spatial scales. Continuous data sets that enable cross-scale studies are very time consuming and expensive to acquire and such extensive field sampling can be invasive. The use of high resolution aerial photography (hrAP) offers an alternative to extensive, invasive, field sampling and can provide large volume, spatially continuous, reference information that can meet the challenges of confidence building and multi-scale analysis.