Site-specific irrigation decisions require information about variations in soil moisture within the rooting depth actively being used by the crop. Producers have been using soil moisture sensors to make irrigation decisions, and it has been shown that soil moisture sensors can reduce water usage without reducing yields. There are still unanswered questions on improving efficiency with soil moisture sensors based on density and location of sensors within a field. This three-year study uses sensors to evaluate the spatio-temporal variability of soil moisture across an 18-ha production field in a corn/soybean rotation. The IDW results show that when uniform irrigation applications are made to the field, fewer sensors that are placed in better locations throughout the field can be as useful as a densely gridded array of sensors. Although, if variable rate irrigation (VRI) is being used, a dense array could be used the first season to fine tune management zones.

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No description available.

AABBSSTTRRAACCTT Dimers and small aggregates as well as compact aggregates of Ag nanoparticles (NPs) were assembled and chemically anchored to supporting surfaces. The supporting surfaces were either glass slides or SiO2 - coated Cu or Au grids for TEM, both chemically functionalized by 3-aminopropyltrimethoxysilane (APTMS). Compact aggregates of Ag NPs incorporating protoporphyrin IX (PPIX) molecules were prepared by adsorption of chlorides in the presence of PPIX. Dimers and small aggregates of Ag NPs were assembled by selected molecular linkers: 4,4'-diaminoazobenzene (DAAB), 4,4'-diaminoterphenyl (DATP) and 5,10,15,20-tetrakis(4-aminophenyl)porphine (TAPP). The most efficient strategy of dimers and small aggregates preparation has been their assembling by a three - step procedure involving (i) attachment of isolated Ag NPs to the NH2 groups of APTMS functionalized TEM grid, (ii) attachment of molecular linker (with two functional NH2 groups in para position) to Ag NPs by a one terminal NH2 group, and (iii) attachment of Ag NPs to the second, free terminal NH2 group of the linker. In this procedure, the control over the perpendicular orientation of the bifunctional linker and its attachment by one terminal group to Ag NP surface has been accomplished by functionalization of Ag NPs by adsorbed citrate...

ABSTRACT Recent global interests in developing hydrogen economy generate substantial research and development for hydrogen production worldwide. Pd membranes are especially suited for high temperature hydrogen separation and membrane reactor applications. Alloying Pd with Ag not only suppresses hydrogen embrittlement, but also increases the permeability of the alloy membrane. The main objective of this work was to carry out fundamental studies to understand the properties of the porous stainless steel (PSS), morphologies of Pd and Ag deposits on PSS, and the structural changes of the membrane layer upon heat treatment. Both coating and diffusion and co-plating techniques were employed in the study. The Pd-Ag membranes that had sandwiched Ag layers suffered from very low selectivity due to the voids formed because of high diffusion rate of Ag. Alloy membranes with high selectivity can be prepared by applying intermediate annealing after each Ag deposition. On the other hand, the homogeneity of the alloy depended very much on the thickness of the deposited layers and annealing temperature and time. A stable co-plating bath was developed to co-plate Pd and Ag simultaneously. Pd-Ag membranes were prepared from co-plating bath using ultrasound to accelerate the plating rate.

Dissertation--Universität zu Köln, 2005. / Bibliogr. p. 367-385.

St. Gallen, Univ., Diss., 2008.

Made available in DSpace on 2015-04-01T12:17:41Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2728849 bytes, checksum: 473329771da433558aad326b78ebbb89 (MD5) Previous issue date: 2013-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A model was used to simulate solute distribution during rapid solidification of a system Ag-15%massCu with initial undercooling of 5 K, 10 K and 30 K. Boettinger et al (1987) measured the microsegregation profile in Ag-Cu alloys superficially treated with a focused electron beam (resolidification). In that work, they found an irregular variation for Cu concentration in cross sections of the resolidified microstructures. In some cases, the profile of concentration versus radius presented a W shape. Current models of microsegregation predict a monotonic variation the concentration depending on the cell radius, which are apparently not in accordance with the acquired measurements. The present study used a numeric model to evaluate the solidification of Ag-Cu alloy under same conditions to the Boettinger´s experiment. Numerical results are for a metallic spherical drop, initially liquid, cooled by convection. Solidification starts in the center of the droplet in a given undercooling. The algorithm used here is based on a model in volumetric average of the quantities and the balance equations in a representative elementary volume for treating a solid/liquid mixture. Inside the droplet transport of energy and mass are repurely diffusive processes of average quantities. The algorithm used permitted a global analysis of the phenomena occurring during the solidification process, as well as a local analysis of the quantities involved, which has been shown to be a prerequisite for the prediction of non-monotonic profiles of microsegregation, such as those measured in the experiment mentioned above. / Foi utilizado um modelo para simular a distribuição de soluto durante a solidificação rápida de um sistema Ag-15%Cu com superresfriamentos iniciais de 5 K, 10 K e 30 K. Boettinger et al (1987) mediram o perfil de microssegregação em ligas Ag-Cu tratadas superficialmente com um feixe de laser (resolidificação). Nesse trabalho, os autores constataram uma variação irregular para a concentração de cobre em seções transversais de células nas microestruturas resolidificadas. Em alguns casos um perfil de concentração ao longo do raio em forma de W foi medido. Os modelos de microssegregação atuais, em geral, preveem uma variação monotônica da concentração em função do raio da célula, o que aparentemente não está de acordo com as medições obtidas. No presente trabalho, foi usado um modelo numérico para avaliar a solidificação de uma liga Ag-Cu em condições análogas às do experimento de Boettinger. Os resultados numéricos são para uma gota metálica esférica, inicialmente líquida, resfriada por convecção. A solidificação tem início no centro da gota em um superresfriamento dado. O algoritmo usado foi desenvolvido previamente para um modelo baseado na tomada de médias volumétricas das grandezas e das equações de balanço descritivas em um volume elementar representativo para tratar com uma mistura sólido/líquido. No interior da gota, os transportes de energia e massa são processos puramente difusivos de grandezas médias. O algoritmo usado permite não apenas uma análise global dos fenômenos que ocorrem durante o processo de solidificação, mas também uma análise local das grandezas envolvidas, o que demonstrou ser condição necessária para a previsão dos perfis não monotônicos de microssegregação, tais como os medidos no experimento mencionado acima.

Nowdays, an emphasis is plased on an antibacterial properties of various products, including floor and coating materials. This work is about an testing of effectivity of the chosen antibacterial agents in the water born and solvent free floor systems which are epoxide or polyurethane based. As first step, the most suitable representative of each floor system was chosen, the silver based agents (respectively silver anion Ag+ based) which should have an antibacterial effect when incorporated into the floor system was chosen. The selected ones are Ag/SiO2, Ag/TiO2, Ag/Al2O3, Ag/ZnO, Ag/BaO, Ag/zeolite, AgI. The necessary was a creating of the test method which has to offer exact and reproducable outputs. At the begining, the method came out from the norms ČSN EN ISO 20645 Squared textiles – Determination of antibacterial activity – Test of diffusion throught the agar plate, ČSN 79 3880 Testing of antimicrobial properties of material and product of boot industry, Antifugal and antibacterial properties. Testing by this way did not bring repriducable outputs. Only the bacterial strains Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus was used according to the norms. The method of recultivation was used for testing. The process is: an application of the coating on the bottom of the Petri´s dish, curing, appplication of the bacterial solution, cultivation for 24 hours at 37 °C, inoculation onto the agar in the Petri´s dish, cultivation for 24 hours at 37 °C, interpretation of the grow/inhibition of the bacteries. The results offer the overview about the advantages and disadvantages of each antibacterial agent in the chosen systems.

La congestión vehicular en Lima es caótica dada la escaza infraestructura vial y el acelerado aumento del parque automotor. En contraste, esta investigación propone implementar el sistema de semaforización inteligente, Ramp Meter, basado en el algoritmo AMS-AG, para reducir los tiempos de viaje vehicular en el óvalo Habich, ubicado en el distrito de San Martín de Porres. La metodología propuesta consta en la recolección de datos estáticos y registro de una lista de verificaciones. Luego se procede con la toma de datos de entrada para construir el modelo, tales como; flujos, velocidades y tiempos de viaje. El primer paquete de datos es utilizado para la construcción y calibración del modelo en el software de microsimulación PTV Vissim 9.0, y el segundo para la validación del modelo. De acuerdo con los resultados de los parámetros de performance vehicular (demora, tiempo de viaje y velocidad) y peatonal (tiempo de viaje, velocidad) de la situación actual y lista de verificaciones, se realiza la propuesta de solución. Del mismo modo, a una proyección a 15 años se estima su funcionalidad en el mediano plazo. Se concluye que la propuesta de mejora a través de la implementación del Ramp Meter, basado en el algoritmo AMS-AG, ofrece mejoras en relación con el performance vehicular, sin embargo, pierde rendimiento a medida que incrementa el flujo vehicular. Cumple con el objetivo principal de la investigación de reducirse los tiempos de viaje vehicular. Por último, se afirma que la inversión económica que demanda es una alternativa viable y rentable. / Vehicle congestion in Lima is chaotic given the lack of road infrastructure and the rapid increase in the number of vehicles. In contrast, this research proposes to implement the intelligent traffic light system, Ramp Meter, based on the AMS-AG algorithm, to reduce vehicle travel times at the Habich roundabout, in San Martin de Porres district. The proposed methodology consists of the collection of static data and registering a checklist. Then, we proceed with taking input data to build the model, such as flows, speed and travels times. The first data packet is used for the construction and calibration of the model in the PTV Vissim 9.0 microsimulation software, and the second one is used for model validation. According to the results of the parameters of vehicular performance (delay, travel time and speed) and pedestrian (travel time and speed) of the current situation and checklist, the proposed solution for roundabout is made. Similarly, at a projection to 15 years its functionality is estimated in the medium term. It is concluded that the improvement proposal through the implementation of the Ramp Meter, based on the AMS-AG algorithm, offers improvements in relation to vehicle performance, however, it loses performance as vehicle flow increases. It fulfills the main objective of the research to reduce vehicle travel times. Finally, it is stated that economic investment that it demands is viable and profitable alternative. / Tesis