Particle Separation Through Taylor-couette Flow And Dielectrophoretic Trapping

As the world population approaches seven billion, a greater strain is put on the resources necessary to sustain life. One of the most basic and essential resources is water and while two thirds of the earth is covered by water, the majority is either salt water (oceans and seas) or it is too contaminated to drink. The purpose of this project is to develop a portable device capable of testing whether a specific source of water (i.e. lake, river, well…) is potable. There are numerous filtration techniques that can remove contaminants and make even the dirtiest water clean enough for consumption but they are for the most part, very time consuming and immobile processes. The device is not a means of water purification but rather focuses on determining the content of the water and whether it is safe. Particles within the water are separated and trapped using a combination of a Taylor Couette fluid flow system and Dielectrophoretic electrodes. This paper explores Taylor Couette flow in a large gap and low aspect ratio system through theory and experimentation with early stage prototypes. Different inner cylinder radii, 2.12cm, 1.665cm and 1.075cm, were tested at different speeds approaching, at and passing the critical Taylor number, 3825, 4713 and 6923 respectively for each cylinder. Dielectrophoretic (DEP) electrodes were designed, fabricated, coated and tested using latex beads to determine the method of integrating them within the fluid flow system. Taylor Couette theory, in terms of the formation of vortices within the large gap, small aspect ratio system, was not validated during testing. The flow pattern generated was more akin to a chaotic circular Couette flow but still served to move the particles toward the outer wall. Fully integrated tests were run with limited success. Recommendations were made to pursue both circular Couette flow as the basis for iv particle separation and dimensional changes in the setup to allow for the formation of Taylor vortices by increasing the radius ratio but still allowing for a larger volume of fluid

Smart electrostatic crop spraying using remote sensing technology

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University LondonFor this thesis, smart spraying robot was designed, constructed and tested to validate the concept of smart pest control. Electrostatic charging of sprayed pesticide was realized in a spray nozzle design that improved plant coverage and reduced wasted pesticide as well as soil pollution. A thorough investigation into electrostatic spraying was conducted, which was accompanied by extensive simulations and experimentation. The results obtained from the simulation experimentation on industry standard electrostatic spray system (ESS) nozzles along with laboratory testing of these nozzles, detecting spray coverage using water sensitive paper and additional optical spray visualization methods gave the necessary insight and experience required to develop a new spray nozzle. Additional COMSOL simulation and experimentation were carried out on a Fan Hydraulic Spray Nozzle (FHSN), the results of which allowed for the effective addition of electrostatic induction capabilities, thereby transforming the (FHSN) into Electrostatic Induction Spray Nozzle (EISN) which is one of the prime parts of the smart spraying system. SOLIDWORKS software was used in the designing parts of this nozzle which were then manufactured using a 3D printer. An AL05D robotic manipulator and a TTRK tracked platform from Lynxmotion ™ were the mini mobile robot components selected for the feasibility study of the smart electrostatic crop spraying system. This mobile robot was equipped with a CCD digital camera, a range detector, and path mark detector to provide the necessary sensors required by the smart electrostatic spray system. A Windows™ based mobile computer in addition to an ARDUINO™ based orksmicrocontroller system were chosen to provide the computational power required by the system. These were arranged in a master – slave configuration, with the main processing for images and motion being conducted inside the master computer using programs created by Matlab smart ™ software. The execution of motion commands and the operation of the range and path mark detection along with operating the spray nozzle were performed on the slave computer using C as the programming language. The manufactured smart electrostatic spray system moves along cotton crop rows with a camera that scans the selected plant for pest infestation on the upper and lower surfaces of plant leaves. When a pest is detected, the spray nozzle is targeted on it at the appropriate distance, and a burst of pesticide destroys it. The results of experiments have shown that using the electrostatic induction system improves coverage 3 to 4 fold and reduces soil contamination by 2 to 4 fold. The system has plenty of room for performance improvement, and future development will make it adaptable for application to other crops and applications.The Iraqi government, the Ministry of Higher Education and Scientific Research and Kerbala Universit

UAH/NASA Workshop on Fluids Experiment System

The Fluids Experiment System is being developed to fit into a Spacelab rack. Papers presented at this workshop describe a variety of fluid and chemical experiments that would be of great benefit to researchers of processes in a low gravity environment

Controlled Ecological Life Support Systems: CELSS '89 Workshop

Topics discussed at NASA's Controlled Ecological Life Support Systems (CELSS) workshop concerned the production of edible biomass. Specific areas of interest ranged from the efficiency of plant growth, to the conversion of inedible plant material to edible food, to the use of plant culture techniques. Models of plant growth and whole CELSS systems are included. The use of algae to supplement and improve dietary requirements is addressed. Flight experimentation is covered in topics ranging from a Salad Machine for use on the Space Station Freedom to conceptual designs for a lunar base CELSS

Microwave soil moisture measurements and analysis

An effort to develop a model that simulates the distribution of water content and of temperature in bare soil is documented. The field experimental set up designed to acquire the data to test this model is described. The microwave signature acquisition system (MSAS) field measurements acquired in Colby, Kansas during the summer of 1978 are pesented

On the dielectrophoretic particle retention in porous media

Dielectrophoresis (DEP) is a very suitable particle manipulation technique that is able to solve a range of separation problems because it is label-free, very sensitive and, if applied correctly, highly selective towards a specific target particle. DEP has mostly been researched and applied (bio-)analytical chemistry to solve separation problems on lab-on-a-chip devices at uL/min throughputs, which makes it incompatible for industrial scale processes. This thesis investigates a high-throughput method, DEP filtration, which is particle retention due to DEP in porous media. Particle retention dynamics in model porous media are scrutinized using simulative and experimental methods. Particle movement in transparent microchannels gives first-hand insight into DEP trapping dynamics. The results presented pave the way toward actual high-throughput DEP filtration that could tackle important separation problems, such as the separation of metal from scrap in recycling

Spacelab J experiment descriptions

Brief descriptions of the experiment investigations for the Spacelab J Mission which was launched from the Kennedy Space Center aboard the Endeavour in Sept. 1992 are presented. Experiments cover the following: semiconductor crystals; single crystals; superconducting composite materials; crystal growth; bubble behavior in weightlessness; microgravity environment; health monitoring of Payload Specialists; cultured plant cells; effect of low gravity on calcium metabolism and bone formation; and circadian rhythm

Summaries of FY 1996 geosciences research

The Geosciences Research Program is directed by the Department of Energy`s (DOE`s) Office of Energy Research (OER) through its Office of Basic Energy Sciences (OBES). Activities in the Geosciences Research Program are directed toward building the long-term fundamental knowledge base necessary to provide for energy technologies of the future. Future energy technologies and their individual roles in satisfying the nations energy needs cannot be easily predicted. It is clear, however, that these future energy technologies will involve consumption of energy and mineral resources and generation of technological wastes. The earth is a source for energy and mineral resources and is also the host for wastes generated by technological enterprise. Viable energy technologies for the future must contribute to a national energy enterprise that is efficient, economical, and environmentally sound. The Geosciences Research Program emphasizes research leading to fundamental knowledge of the processes that transport, modify, concentrate, and emplace (1) the energy and mineral resources of the earth and (2) the energy by-products of man

The 1992 Shuttle Small Payloads Symposium

The 1992 Shuttle Small Payloads Symposium is a continuation of the Get Away Special Symposium convened from 1984 through 1988, and is proposed to continue as an annual conference. The focus of this conference is to educate potential Space Shuttle Payload Bay users as to the types of carrier systems provided and for current users to share experiment concepts

ENHANCED SOIL STRUCTURING BENEATH WHITE CLOVER AND ITS IMPACT ON NUTRIENT TRANSPORT

Previous work at IGER has revealed that soil structural differentiation under white clover is phenomenally rapid and enhanced when compared with ryegrass. White clover is one of the most nutritious and widely distributed forage legumes. Its use is advocated in sustainable systems of livestock production because of its ability to acquire atmospheric N through biological fixation in the root nodules. It thus provides an economically viable alternative to the N-demanding conventional system, and a possible solution to reduce the environmental impacts of nitrate leaching from agricultural land. There are, however, potentially negative impacts associated with improving soil aggregation through the use of clover that need further investigation. It appears that legume-based systems are not environmentally benign: similar amounts of N and P are leached from beneath grass-clover swards as those leached from beneath fertilised grass operating at the same level of production. In some circumstances, clover rich swards can give rise to very high levels of nitrate leaching. Thus, this observation of clover induced soil aggregation has important implications for the pollutant transport qualities of soils and for the organic/conventional agriculture debate. Re-packed soil columns of four soil series and 0.5 m intact monoliths of the Crediton series were planted with white clover, perennial ryegrass and a mixture of the two species, and managed according to an organic and conventional farming regime. Visual observations revealed a rapid enhancement in soil structure beneath white clover compared to ryegrass and unplanted soil. A novel technique to determine oxygen diffusion as an indicator of soil porosity, gave a diffusion rate that was nearly nine times greater than that of the grass treatments and fifteen times greater than the unplanted control soil, with intermediate values for the mixed treatment Thus enhanced structural differentiation beneath white clover was supported by greater permeability to air and freer drainage to water. Structural stability tests suggested that white clover improved the ability of the soil to maintain its structure under the action of water, and was estimated to be three times more stable than ryegrass. There was also evidence which implied improved shear strength and resistance to mechanical forces. Differences in soil structure were verified with water retention measurements, which showed a greater proportion of macropores. The void structure was simulated with the 30 Pore-Cor network model, which also suggested a number of larger pores and a saturated hydraulic conductivity which was four times greater than ryegrass. This also highlighted inadequacies in the current standard ISO protocol for water retention. The solute transport studies showed elevated levels of nitrate and phosphate leaching. Concomitant transport of bromide inferred structural differentiation and changes in leaching dynamics. In addition, white clover allowed the passage of greater volumes of water. Most importantly, this was manifested at the soil profile scale and therefore likely to be of consequence in the field. The implications of the research are that enhanced soil structure beneath white clover alters the transport of gases, water, nutrients and other dissolved substances. Further understanding of these soil processes are needed before advocating the use of forage rich legumes in sustainable systems, and for the development of management strategies