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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Physico-chemical, nutritional and functional properties of defatted marama bean flour

Maruatona, Gaamangwe Nehemiah 11 June 2009 (has links)
Marama bean (Tylosema esculentum (Burch) A. Schreib) is an underutilised, drought-tolerant legume native to the drier parts of Botswana, Namibia and South Africa. The bean is comparable to soya beans in protein content and quality whereas its oil content is comparable to that of peanuts. By adding value to the marama bean through processing into protein-rich flours, its utilisation may be increased. Therefore, one of the objectives of this study was to adopt suitable low-cost processing technologies used for soya processing to produce protein-rich marama bean flours. The effect of dry heating of whole marama beans on lipoxygenase enzymes of its defatted flour was determined since oxidative rancidity catalysed mainly by lipoxygenase enzymes can reduce the shelf-life of the flour. The presence of trypsin inhibitors can affect the protein digestibility of the marama bean flour adversely. The effect of dry heating of whole marama beans on in-vitro protein digestibility and amino acid content of its defatted flour was determined. Lastly, the effect of dry heating of whole marama beans on the protein-related functional properties of the resultant defatted flour was determined. The presence of lipoxygenase iso-enzymes (L-1 and L-2) activity in marama beans was determined by a visual and spectrophotometeric method using unheated soya beans as reference. Lipoxygenase iso-enzymes (L-1 and L-2) activity was not detected in marama beans. This may possibly suggest that these lipoxygenase iso-enzymes are absent or possibly inhibited in marama beans. In an attempt to optimise dry heating to inactivate trypsin inhibitors in marama beans, whole marama beans were dry heated at 100°C, 120°C and 150°C, respectively for 20 min. Defatted flours prepared from the heated marama beans (HMF’s) were analysed for their trypsin inhibitor activity using defatted flours from unheated marama beans (UMF) and soya beans (USF) as control and reference samples, respectively. Trypsin inhibitor activity in UMF was almost four and half times higher than in USF. Dry heating of whole marama beans at 150°C/20 min significantly reduced the trypsin inhibitor activity in its defatted flour to almost zero probably due to inactivation of the trypsin inhibitor. The effect of dry heating of whole marama beans at 150°C/20 min on the physico-chemical, nutritional and protein-related functional properties of defatted marama bean flour was determined. UMF was used as a control while USF and HSF were used as reference samples. HMF had higher protein content but lower fat content than UMF. It is suggested that dry heating disrupted the lipid bodies of the marama beans allowing more oil to be expelled during coarse milling of the flour. Heating significantly reduced the L* values of marama and soya bean flours possibly due to Maillard browning reactions. Heating significantly increased in-vitro protein digestibility of marama and soya bean flours probably due to protein denaturation and inactivation of trypsin inhibitors. Heating generally decreased the amino acid contents of marama and soya bean flours possibly due to chemical modification of the amino acids. UMF and HMF can potentially be used to improve protein quality in marama-cereal composite flours, porridges and breads. Heating significantly decreased the nitrogen solubility index (NSI) and emulsifying capacity (EC) of marama and soya bean flours possibly due to protein denaturation and/or cross-linking. This may make HMF and HSF not suitable for applications in emulsion type meat products such as sausages because emulsion formation is critical during processing of sausages. Heating significantly decreased the foaming capacity of soya flour but did not have an effect on that of marama bean flour probably due to their high residual fat content which may have disrupted protein films during foam formation. UMF has a potential to be used in comminuted meat products because of its relatively high NSI, EC and OAC. The laboratory process used in this study can be modified and adopted by SME’s to produce defatted marama bean flours with potential applications in bakery and meat products and as a protein supplement in composite marama-cereal products. / Dissertation (MSc)--University of Pretoria, 2011. / Food Science / unrestricted
172

Vliv nízkonákladových leteckých společností na cestovní ruch / The influence of low cost airlines on tourism

Hovorková, Dana January 2008 (has links)
In the first chapter is defined the fundamental concept of low cost airlines. Second and third section is dedicaded to history, creation and sequential developement of theese carriers and as well their characteristics. Following part is attended to airline traffic and its importance for tourism. In the last most extensive section, is analysed the influence of airline industry on tousim in the Czech Republic, at firts in general view of low cost carriers and tourism and further is this influence searched and analysed through three concrete airlines and four chosen regions.
173

Projeto e construção de laborátórios de biossegurança NB3 de baixo custo. / Design and constrution of low cost BSL3

Francisco José Camilo Hernandes 08 May 2008 (has links)
Laboratórios de biossegurança são classificados em quatro níveis de risco (1 a 4), sendo constituídos de combinações de práticas e técnicas de laboratório, equipamento de segurança e instalações do laboratório. Cada combinação é especificamente adequada para as operações realizadas, vias de transmissões documentadas ou suspeitas de agentes infecciosos e em monitoramento das atividades de laboratórios. O objetivo deste trabalho foi o de tornar possível a construção de laboratórios de Biossegurança Nível 3 (NB3) com baixo custo, mantendo-se as condições mínimas de biossegurança no aspecto da engenharia. Como resultado seis laboratórios NB3 foram construídos para o projeto da FAPESP, denominado Rede de Diversidade Genética Viral (VGDN), com finalidade de diagnóstico de vírus respiratórios e mais uma laboratório para o Ministério da Agricultura, situado no LANAGRO de Pernambuco na cidade de Recife. / Biosafety laboratories are classified into four levels of risk (1 to 4), and consist of combinations of laboratory practices and techniques, safety equipment and facilities of the laboratory. Each combination is particularly suitable for the operations; routes of transmission documented or suspected infectious agents in tracking the activities of laboratories. The objective of this work was to make possible the construction of laboratories for Biosafety Level 3 (BSL3) with low cost, remaining the minimum conditions of biosecurity in the aspect of engineering. As results were built six laboratories BSL3 of FAPESP for the project, called Viral Genetics Diversity Network (VGDN), with the purpose of diagnosis of respiratory viruses and another laboratory for the Ministério da Agricultura, located in LANAGRO of Pernambuco in the city of Recife.
174

Low cost air quality monitors in agriculture

Dausman, Taryn Bette Catherine 01 May 2017 (has links)
Agriculture workers can be exposed to hazardous concentrations of airborne contaminants such as, particulate matter (PM), carbon dioxide (CO2), and volatile organic compounds (VOCs). Exposure to these contaminants has been associated with a high prevalence of acute and chronic respiratory symptoms: coughing, wheezing, shortness of breath, and phlegm, as well as a reduction in lung function. Commercial low-cost indoor air quality (IAQ) monitors have the ability to detect many of the contaminants commonly found in agriculture. Limited research has been conducted on the performance of low-cost monitors in different occupational settings. Therefore, the purpose of this study was to evaluate whether the Foobot (Airboxlab, San Francisco, CA, USA), a low-cost (IAQ) monitor, is sufficiently robust to operate in agricultural environments and provide useful and accurate information to farmers. Foobots were deployed at two sites, a tractor repair shop (“Shop”) for 43 days and a finishing room in a swine production building (“Barn”) for 40 days, where they monitored PM2.5, CO2, and VOCs. Reference direct-reading monitors to compare Foobot readings were collocated with the Foobots. Paired sample results were compared over 19 days at the shop and 21 days at the barn. At neither of the two sites did the Foobots meet the National Institute for Occupational Safety and Health (NIOSH) acceptable bias criterion of ± 10% when compared to the reference monitors. Linear regression results indicate that a strong linear relationship does not exist (R2< 0.66) between the Foobots and reference monitors. A significant difference (P< 0.031) was found between contaminant concentrations reported by each Foobot but the difference was not found to be substantial. The Foobot CO2 and VOC concentrations were highly correlated (R2=0.99). However, a strong linear relationship between the Foobot CO2 concentrations and the reference CO2 concentrations was not found at the shop (R2 = 0.02) or barn (R2 = 0.61). After 40 days in the barn, the Foobots were reporting that damage had occurred to the sensors and were no longer functioning. In addition, the PM sensors in the three Foobots in the barn were contaminated after the study. Therefore, it was concluded that the Foobots were unable to supply farmers with accurate information and were not durable enough for agricultural environments. Future research will investigate the use of other low-cost monitors in agriculture.
175

Small Changes with Big Results: Practical and Low-cost Ways to Enrich Your Early Childhood Environment so It Is Engaging and Inspiring for Young Learners

Isbell, Rebecca, Evanshen, Pamela, Lane, H, Baker, A 01 November 2011 (has links)
No description available.
176

Next generation low-cost automated guided vehicle

Dzezhyts, Yevheniy January 2020 (has links)
Automated guided vehicles (AGVs) are the key equipment of flexible production systems and an important means for realizing a modern logistics system that meets the demands of Industry 4.0. AGVs are used from the mid 50th to delegate monotonous work of delivering products from the human to the automated device. In the long run, the usage of AGVs brings huge benefits to the manufacturing companies. But the purchase and installation of these devices significantly increase operational costs. This fact halts small and medium-sized enterprises from adopting this technology on their shop floors. The idea of this thesis work is to design and create a device that can be retailed at a significantly lower price without compromising flexibility and functional properties, to be used by smaller businesses. For this mater are used more affordable parts that can bring the cost down of a final product. This work describes the process of developing a differential drive mobile platform under the control of the robotic operating system. The process includes the development of a virtual model; selection of required components and investigation of their compatibility; development of chassis, suspension, and gear system; development of a hardware interface to interact with hardware components; configuration of different algorithms of control, cartography, and navigation; evaluation of the device. The research method is used in this work is design and creation due to the necessity of creating a physical prototype. The budget specification for the project was set to 50000 SEK and the desired payload capacity was set to 100kg. The work has resulted in the creation of a prototype of the AGV. The cost of the project is 20595 SEK. The evaluation of a prototype resulted in a maximum towing force of 300N. The load capacity is limited by the mobile base is 400kg. Safety sensors are not used in this project as the device was meant to operate in a controlled environment. The work also gives an evaluation of the Gmapping algorithm in case of using the laser scanner (RPlidar A1) and two algorithms of navigation stack: TrajectoryPlannerROS and DWA planner. The final prototype is evaluated to support an autonomous movement within a controlled environment.
177

Tilt sensing with low-cost inertial measurement units (IMUs) : Sensor calibration, accuracy specifications and application range

Riedesel, Philipp January 2016 (has links)
Many surveying engineering applications require the knowledge of the orientation parameters of instruments. One can use inertial measurement units (IMUs) to determine that. IMUs are combinations of several inertial sensors and comprise at least an accelerometer and a gyroscope. Therefore, they can detect accelerations and angular rates in a three-dimensional space. As micro-electro-mechanical systems, the sensors are increasingly getting smaller and lighter, but without being reduced in their accuracy. The smaller size facilitates diverse placing of the sensors, which allows a variety of uses. Moreover, several low-cost IMUs have been devised since the development of single-board computers. The main objectives of this work are to determine tilts using a low-cost IMU, and the accuracy of the sensor. Furthermore, it studies general IMU applications in surveying engineering, and examines whether low-cost versions are applicable. To fulfil the objectives, the study was based on a selected low-cost IMU. Two programs were developed as part of this work. One was to control the sensor and the other, to calculate the tilts and analyse the data. The IMU was mounted in front of the objective of the total station and aligned in different reference orientations. All measurements were performed under controlled thermal conditions. Thereby, it was ensured that no falsifications could appear due to ambient temperature influences. As a first step, the sensor calibration process was completed. It helped determine the signal offset parameter and their time-dependent change. The calibration was done using two present methods, the six-position and the multi-position methods. The calibrated IMU helped determine the tilts. This was done in the case of the accelerometer via trigonometric functions, which allowed an absolute orientation statement. In contrast, the gyroscope provided relative orientation with the multiplication of the detected angular variance and the time that passed. After that, a target-actual comparison with the reference information of the total station helped determine the external accuracy of the tilt from the IMU. Moreover, multiple measurements could give a statement of the internal accuracy. Finally, the Kalman Filter was added to smooth out the sensor data and combine it in real-time. The calibration methods showed similar results, and it was striking that the sensors did not show the expected drifts. The reason could be related to a pre-calibration by the manufacturer. On the one hand, the used IMU showed differences in the total station alignments in the order of 0.798° for the accelerometer and up to 4.3° for the gyroscope with the calibrated data. On the other, the differences in repeated measurements were at 0.024° for the accelerometer and 0.5° for the gyroscope. It was figured out different possible applications of IMUs in surveying engineering. Among other things, these included orientation monitoring of sensor platforms or the determination of the external orientation of unmanned aerial systems. For these applications, the usability depends on the achievable accuracy. In the case of the IMU chosen in this study, the proven accuracy is too inaccurate for these applications. There is a need for further investigation because the use of another sensor type may rectify the insufficient accuracy problem. Moreover, to achieve better accuracies and to make it possible to use the IMU in different ambient temperatures, the temperature influence must be determined.
178

Sorption of Stormwater Pollutants for Five Material Mixtures: A batch Equlibrium Study

Rydholm, Fredrik January 2021 (has links)
Blue-green infrastructure have been more lucrative during the last 30 years, since urbanizationbrings more impervious surfaces that increases stormwater runoff volumes. Amongst thedifferent blue-green infrastructures there are e.g., constructed wetlands and swales. Blue-greeninfrastructure means more natural management of the stormwater, such as infiltration. Forinfiltration of water, the hydraulic conductivity is an important parameter, but also the abilityto remove dissolved pollutants. In literature, various studies of filter materials are only testedfor single dissolved pollutants, which might be a disadvantage as this does not represent fieldconditions where metals usually co-exist. Economic costs are also an important parameter,unfortunately not always targeted in research. In this thesis, the efficiency of five different material mixtures for removing typical dissolvedstormwater pollutants: chromium (Cr), copper (Cu), nickel (Ni), phosphorus (P), lead (Pb) andzinc (Zn) were studied. The mixtures were following: 1) crushed rock + soil (RO_SO) 2)crushed rock + soil + LECA 4/10 + biochar (RO_SO_BC_LC4). 3) crushed rock + soil + LECA10/20 + biochar (RO_SO_BC_LC10). 4) Soil (SO). 5) crushed rock + soil + biochar(RO_SO_BC). This study was a part of blue-green investments that is being made in Östersundmunicipality and the use of low-cost materials for stormwater treatment are examined. The study was made using batch equilibrium tests, to determine the sorption capacity fordifferent material mixtures, using dissolved metal- and P-solutions. The measured data werefitted to Freundlich, Langmuir, Temkin, Dubinin-Radushkevich and Redlich-Petersonisotherms. Economic feasibility has also been compared between the material mixtures.Results showed that SO had the best sorption capacity for all metals and P, with rankingPb &gt; Cr &gt; Cu &gt; Ni &gt; Zn for the metals. All material mixtures showed a removal efficiency of79-99%, at the lowest concentration (1mg/L) for the metals and 31-62% for the lowestconcentration of P-single solution (1mg/L). Using additional materials in the mixtures, such asbiochar, slightly improved the sorption capacities of Pb and P. Redlich-Peterson isothermsprovided the best fits to the data. An economic evaluation of the ingoing materials shows thatSO and RO_SO are undoubtedly the most feasible alternatives for removal of targeted metalsand P.
179

Marketingová strategie nízkonákladové letecké společnosti / Marketing Strategy of Low-cost Airline

Chaloupková, Markéta January 2018 (has links)
The diploma thesis deals with the marketing strategy of low cost airlines. The theoretical part describes low cost air transport and also define marketing tools. The practical part is focused on the low cost airline Wizz Air. In practical part of the work is included a questionnaire survey. Based on the findings, were proposed possible marketing improvements for Wizz Air airline.
180

Examining the effect of school development loans on education capacity and quality: evidence from Ghana and Uganda

Sheridan, Scott 29 September 2021 (has links)
Increased investment in education to build capacity and quality is essential if the world is to meet its ambitious targets on Sustainable Development Goal (SDG) 4: Quality Education. There are 258 million school aged children out of school, of which 98 million are in Sub-Saharan Africa (SSA). Low-income countries are experiencing dramatic growth in their populations and have severe limitations on their ability to fund the required infrastructure development. The financing gap is estimated to be US$ 1.8 trillion to achieve SDG goals (Education Commission, 2016). Low-Cost Private Schools (LCPS), accessible to children from poor families, are growing rapidly in SSA to fill this gap. This study is focused on the potential to increase the use of innovative financing to improve capacity and quality for LCPSs. Most innovative finance schemes utilise some form of a School Development Loan to achieve greater investment in capacity and quality of education. The study evaluates the effect of School Development Loans on several indicators which have been directly associated with capacity and quality, using data from Ghana and Uganda, countries estimated to need a combined 5 million new seats for children by 2023 (7% of their combined population) to account for population growth. Capacity indicators include the Number of Students enrolled in the school and the Number of Classrooms available for use. The indicators of school quality were Pupil Teacher Ratios (Lower), the Number of Washrooms, the Number of Washrooms Dedicated to Girls and the Number of Extracurricular Programmes Offered by the school. The study leveraged pairwise correlation and regression analysis to identify the most directly linked indicators, followed by a mean difference analysis. The study finds that schools taking out School Development Loans have more classrooms, higher enrolment, greater amounts of washrooms and extracurricular activities on offer, indicating that School Development Loans increase both capacity and quality at LCPSs. Despite the encouraging findings, it is early to assess whether the significance of the increase over time. The study recommends a fully coordinated Randomised Control Trial (RCT) for further research, where data is collected prior to the school receiving its first loan and again at the conclusion of the loan.

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