The global mobile data usage has grown nearly 70\% annually in recent years. The huge mobile data usage requirement drives the mobile industry to brace the formidable challenge and invent next-generation mobile technologies. LTE, as a successful cellular technology, has gained tremendous importance in recent years due to its high data-rates and improved data access method for mobile devices. Even though LTE still may not be able to meet the mobile data challenge due to current spectrum scarcity in licensed bands. Thus, cellular network faces serious challenges to provide high performance mobile service to end users in the near future. In order to sustain the possible increase in mobile capacity demand, utilizing the unlicensed band as a supplementary band for LTE is being considered as a promising solution to expand the capacity of mobile systems. Based on the innovation of carrier aggregation, 3GPP has approved a study item on LAA-LTE, which will assist LTE by offloading mobile data in unlicensed band. Thus, LAA-LTE will operate in the spectrum that overlaps with WiFi, which is another popular unlicensed band technology. The concern is that LAA-LTE and WiFi are unlikely to have mechanisms to directly coordinate with each other, considering different core networks, backhauls and deployment plans of LAA-LTE and WiFi networks. The overarching goal of my research is to investigate the following two aspects: 1) Investigate how LTE will impact on WiFi using experimental analysis when both of them share the same channel, 2) Develop a possible coexistence algorithm to trigger the coexistence between LAA-LTE and WiFi in unlicensed band.

Desalination has been increasingly adopted over the last decades as an option, and sometimes as a necessity to overcome water shortages in many areas around the world. Today, several thermal and physical separation technologies are well established in large scale production for domestic and industrial purposes.  Membrane distillation is a novel thermally-driven process that can be adapted effectively for water desalination or water treatment in industrial applications, due to its potential lower energy consumption and simplicity. The general objective of this thesis is to contribute to the technical understanding of membrane distillation as a new technology in water treatment for both industrial and drinking water purposes, as a starting point for further improvement. The thesis includes experimental and numerical investigations that highlight some aspects of the technology application and fundamental aspects. In the field of industrial application, an experimental and numerical assessment has been carried out on an Air Gap Membrane Distillation (AGMD) prototype to assess the utilization of the technology in thermal cogeneration plants; in particular, demineralization of water boiler feed water and treating flue gas condensate. The main assessment parameters were water quality and energy consumption. The results from full-scale simulations of a system of 10 m3/hr production capacity,  connected to the district heating network were as follows: 5 to 12 kWh/m3 specific thermal energy consumption, and  0,6 to 1,5 kWh/m3 specific electricity consumption, depending upon the heat source (district heat supply line or low-grade steam). For desalination applications, experimental and simulation work was conducted on an AGMD semi-commercial system as part of the EU MEDESOL project. The aim was to evaluate AGMD performance with saline water of 35 g/l NaCl in order to establish an operation data base for simulation of a three-stage AGMD desalination system. Specific thermal energy consumption was calculated as 950 kWht/m3 for a layout without heat recovery, and 850 kWht/m3 for a layout with one stage heat recovery.  The lack of internal heat recovery in the current MD module means that most of the heat supplied to MD system was not utilized efficiently, so the thermal energy consumption is high. This would mean that a large solar field is needed. In order to analyze the flow conditions in feed flow and cooling channels, CFD was used as tool to analyze a spacer-obstructed flow channel for different types of spacer geometrical characteristics: flow of attack angle, spacer to channel thickness ratio, and void ratio. Velocity profiles, shear stress, and pressure drop were the main assessment criteria. Results show the flow of attack angle has a very minimum effect on the performance of spacers. The effect of spacer to channel thickness ratio was significant in all assessment parameters. Higher void ratios were found advantageous in promoting flow mixing, but resulted in lower sheer stress and hence reduced heat transfer. Physical modifications were implemented on a semi-commercial AGMD prototype to assess experimentally any improvement in its performance. These modifications were mainly focused on reducing the conductive heat transfer losses by modifying the physical support in the air gap that separates the membrane from the condensation surface. In addition, several feed channel spacers were tested and assessed based on their effect in increasing the mass transfer while maintaining or reducing pressure drop. The modifications yielded a two-fold augmentation: slight increase in the distillate mass flow rate (9-11%), and increased thermal efficiency (6%). The pressure drop in the module was reduced by 50% through selecting the appropriate spacer that would achieve the above mass flow rate increase. / QC 20111021

Desde o seu surgimento o motor de combustão interna é a alternativa de fornecimento de potência mais utilizada no mundo em veículos de passeio e transporte de cargas. De fato, observa-se no dia-a-dia uma forte dependência da utilização de motores e, atualmente, os estudos visando o seu aumento de eficiência e a diminuição de emissões poluentes estão cada vez mais intensos. Com os grandes avanços ocorridos na disponibilização de computadores, existe uma tendência contínua para a utilização de técnicas computacionais auxiliando no projeto de motores. No entanto, o maior desafio é simular o escoamento altamente tridimensional, turbulento e transiente, com o uso de modelos de turbulência e combustão, que tenham bom compromisso com a física envolvida. Neste âmbito, o presente trabalho tem o objetivo de desenvolver uma validação de metodologias numérica e experimental, para avaliar o comportamento dinâmico e reativo do escoamento em motores de combustão interna. A simulação é aplicada a um motor Honda GX35, que possui vasto uso comercial em roçadeiras, motocicletas de baixo custo e, atualmente, em Veículos Autônomos Não Tripulados (VANT), dentre outros. A análise tem como base soluções numéricas pelo método dos volumes finitos, usando o programa comercial Star-cd/es-ice. Para resolver o escoamento turbulento o modelo adotado foi o k-ω SST, com aproximação para baixo Reynolds e tratamento de parede híbrido. O modelo de combustão ECFM-3Z foi empregado para resolver o escoamento reativo. O combustível utilizado foi metano em mistura estequiométrica. Os resultados numéricos são confrontados com resultados experimentais, com o objetivo de examinar o estado da arte dessas metodologias. Valores transientes de pressão no interior do cilindro, vazão mássica de ar, fração mássica queimada, em relação ao eixo de manivelas e os produtos da combustão são confrontados A presença de recirculações na admissão e no cilindro foram detectadas e discutidas. As evoluções da pressão interna no cilindro e da vazão mássica de ar resultantes da simulação numérica apresentaram um bom comportamento, quando confrontado com dados experimentais. Os resultados da fração mássica de combustível queimado revelam características importantes de funcionamento do motor. / Since its inception, the internal combustion engine is the alternative of delivering power most used worldwide in passenger vehicles and transportation. Indeed, it is observed in day-to-day a strong dependency on the use of engines, and currently studies aiming at its increased efficiency and reduced emissions are becoming more intense. With the great advances in the availability of computers, there is a continuing trend towards the use of computational techniques aiding in the engine designs. However, the main challenge is to simulate the highly three-dimensional, transient and turbulent flows with the turbulence and combustion models, which have good compromise with the involved physics. In this context, this work aims to develop a validation of numerical and experimental methods for evaluating the dynamic and reactive behavior of the flow in internal combustion engines. The simulation is applied to a Honda GX35 engine, which has commercial application in brushcutters, motorcycles of low cost, Unmanned Autonomous Vehicles (UAV), among others. The analysis is based on numerical solutions by the finite volume method, using the commercial software Star-CD / esice. To solve the turbulent flow the model adopted was the k-ω SST, in its Low Reynolds approach with hybrid treatment near the walls The ECFM-3Z combustion model was employed to solve the reactive flow. The fuel used was methane in the stoichiometric mixture. The numerical results are compared with experimental ones, in order to examine the state of art of these methodologies. Transient values of cylinder inside pressure, mass air flow, mass fraction of the fuel burned, in relation to the crankshaft angle and the combustion products are confronted The presence of recirculation in the intake duct and cylinder were detected and discussed. The evolutions of the internal cylinder pressure and mass flow rate of air showed a good behavior, when confronted with experimental data. The results of the burned mass fraction reveal important characteristics of engine operation.

Desde o seu surgimento o motor de combustão interna é a alternativa de fornecimento de potência mais utilizada no mundo em veículos de passeio e transporte de cargas. De fato, observa-se no dia-a-dia uma forte dependência da utilização de motores e, atualmente, os estudos visando o seu aumento de eficiência e a diminuição de emissões poluentes estão cada vez mais intensos. Com os grandes avanços ocorridos na disponibilização de computadores, existe uma tendência contínua para a utilização de técnicas computacionais auxiliando no projeto de motores. No entanto, o maior desafio é simular o escoamento altamente tridimensional, turbulento e transiente, com o uso de modelos de turbulência e combustão, que tenham bom compromisso com a física envolvida. Neste âmbito, o presente trabalho tem o objetivo de desenvolver uma validação de metodologias numérica e experimental, para avaliar o comportamento dinâmico e reativo do escoamento em motores de combustão interna. A simulação é aplicada a um motor Honda GX35, que possui vasto uso comercial em roçadeiras, motocicletas de baixo custo e, atualmente, em Veículos Autônomos Não Tripulados (VANT), dentre outros. A análise tem como base soluções numéricas pelo método dos volumes finitos, usando o programa comercial Star-cd/es-ice. Para resolver o escoamento turbulento o modelo adotado foi o k-ω SST, com aproximação para baixo Reynolds e tratamento de parede híbrido. O modelo de combustão ECFM-3Z foi empregado para resolver o escoamento reativo. O combustível utilizado foi metano em mistura estequiométrica. Os resultados numéricos são confrontados com resultados experimentais, com o objetivo de examinar o estado da arte dessas metodologias. Valores transientes de pressão no interior do cilindro, vazão mássica de ar, fração mássica queimada, em relação ao eixo de manivelas e os produtos da combustão são confrontados A presença de recirculações na admissão e no cilindro foram detectadas e discutidas. As evoluções da pressão interna no cilindro e da vazão mássica de ar resultantes da simulação numérica apresentaram um bom comportamento, quando confrontado com dados experimentais. Os resultados da fração mássica de combustível queimado revelam características importantes de funcionamento do motor. / Since its inception, the internal combustion engine is the alternative of delivering power most used worldwide in passenger vehicles and transportation. Indeed, it is observed in day-to-day a strong dependency on the use of engines, and currently studies aiming at its increased efficiency and reduced emissions are becoming more intense. With the great advances in the availability of computers, there is a continuing trend towards the use of computational techniques aiding in the engine designs. However, the main challenge is to simulate the highly three-dimensional, transient and turbulent flows with the turbulence and combustion models, which have good compromise with the involved physics. In this context, this work aims to develop a validation of numerical and experimental methods for evaluating the dynamic and reactive behavior of the flow in internal combustion engines. The simulation is applied to a Honda GX35 engine, which has commercial application in brushcutters, motorcycles of low cost, Unmanned Autonomous Vehicles (UAV), among others. The analysis is based on numerical solutions by the finite volume method, using the commercial software Star-CD / esice. To solve the turbulent flow the model adopted was the k-ω SST, in its Low Reynolds approach with hybrid treatment near the walls The ECFM-3Z combustion model was employed to solve the reactive flow. The fuel used was methane in the stoichiometric mixture. The numerical results are compared with experimental ones, in order to examine the state of art of these methodologies. Transient values of cylinder inside pressure, mass air flow, mass fraction of the fuel burned, in relation to the crankshaft angle and the combustion products are confronted The presence of recirculation in the intake duct and cylinder were detected and discussed. The evolutions of the internal cylinder pressure and mass flow rate of air showed a good behavior, when confronted with experimental data. The results of the burned mass fraction reveal important characteristics of engine operation.

Desde o seu surgimento o motor de combustão interna é a alternativa de fornecimento de potência mais utilizada no mundo em veículos de passeio e transporte de cargas. De fato, observa-se no dia-a-dia uma forte dependência da utilização de motores e, atualmente, os estudos visando o seu aumento de eficiência e a diminuição de emissões poluentes estão cada vez mais intensos. Com os grandes avanços ocorridos na disponibilização de computadores, existe uma tendência contínua para a utilização de técnicas computacionais auxiliando no projeto de motores. No entanto, o maior desafio é simular o escoamento altamente tridimensional, turbulento e transiente, com o uso de modelos de turbulência e combustão, que tenham bom compromisso com a física envolvida. Neste âmbito, o presente trabalho tem o objetivo de desenvolver uma validação de metodologias numérica e experimental, para avaliar o comportamento dinâmico e reativo do escoamento em motores de combustão interna. A simulação é aplicada a um motor Honda GX35, que possui vasto uso comercial em roçadeiras, motocicletas de baixo custo e, atualmente, em Veículos Autônomos Não Tripulados (VANT), dentre outros. A análise tem como base soluções numéricas pelo método dos volumes finitos, usando o programa comercial Star-cd/es-ice. Para resolver o escoamento turbulento o modelo adotado foi o k-ω SST, com aproximação para baixo Reynolds e tratamento de parede híbrido. O modelo de combustão ECFM-3Z foi empregado para resolver o escoamento reativo. O combustível utilizado foi metano em mistura estequiométrica. Os resultados numéricos são confrontados com resultados experimentais, com o objetivo de examinar o estado da arte dessas metodologias. Valores transientes de pressão no interior do cilindro, vazão mássica de ar, fração mássica queimada, em relação ao eixo de manivelas e os produtos da combustão são confrontados A presença de recirculações na admissão e no cilindro foram detectadas e discutidas. As evoluções da pressão interna no cilindro e da vazão mássica de ar resultantes da simulação numérica apresentaram um bom comportamento, quando confrontado com dados experimentais. Os resultados da fração mássica de combustível queimado revelam características importantes de funcionamento do motor. / Since its inception, the internal combustion engine is the alternative of delivering power most used worldwide in passenger vehicles and transportation. Indeed, it is observed in day-to-day a strong dependency on the use of engines, and currently studies aiming at its increased efficiency and reduced emissions are becoming more intense. With the great advances in the availability of computers, there is a continuing trend towards the use of computational techniques aiding in the engine designs. However, the main challenge is to simulate the highly three-dimensional, transient and turbulent flows with the turbulence and combustion models, which have good compromise with the involved physics. In this context, this work aims to develop a validation of numerical and experimental methods for evaluating the dynamic and reactive behavior of the flow in internal combustion engines. The simulation is applied to a Honda GX35 engine, which has commercial application in brushcutters, motorcycles of low cost, Unmanned Autonomous Vehicles (UAV), among others. The analysis is based on numerical solutions by the finite volume method, using the commercial software Star-CD / esice. To solve the turbulent flow the model adopted was the k-ω SST, in its Low Reynolds approach with hybrid treatment near the walls The ECFM-3Z combustion model was employed to solve the reactive flow. The fuel used was methane in the stoichiometric mixture. The numerical results are compared with experimental ones, in order to examine the state of art of these methodologies. Transient values of cylinder inside pressure, mass air flow, mass fraction of the fuel burned, in relation to the crankshaft angle and the combustion products are confronted The presence of recirculation in the intake duct and cylinder were detected and discussed. The evolutions of the internal cylinder pressure and mass flow rate of air showed a good behavior, when confronted with experimental data. The results of the burned mass fraction reveal important characteristics of engine operation.

In this era of globalisation and fierce competition amongst businesses, there is a need to improve advanced operations management philosophies such as just-in-time (JIT) manufacturing to enhance business performance. Literature review shows that there is no mechanism so far to identify key JIT drivers relevant to a given organisation and its production processes, and their impact on enterprise performance. The research carried out here therefore involved the development of a generic performance measurement model to identify and capture the influence of JIT practices on enterprise performance. A conceptual performance measurement model, which was designed based on comprehensive literature review and informal interviews/discussions with both academic researchers and industry practitioners describes the link between JIT drivers (Xi) and measurable performance (Y). This mathematically determined model is aimed at assisting managers in the systematic identification of the influence of key JIT drivers on enterprise performance using a multidimensional tool such as the extended balanced scorecard. The case study approach was selected as the most suitable methodology for testing and validating the conceptual model in JIT enabled production plant and was applied to the production process of Denso Manufacturing (UK) Ltd., a global automotive component manufacturer. A novel eight-step implementation procedure was designed to collect data, which were analysed and validated by design of experiments, linear mathematical modelling, computer based dynamic simulation and analytic hierarchy process tool. The performance measurement model was then successfully applied to a non-automotive component production plant (Risane Ltd.). In conclusion, the performance measurement model can now be suitably applied to JIT enabled manufacturing environments using relevant organisation specific JIT drivers and key performance indicators to optimise system performance. The contribution to knowledge is an innovative, user friendly, robust and multidimensional performance measurement model enabling industry practitioners to optimise JIT processes with substantial performance enhancement. The model could also be applied by future researchers to other operations management philosophies and industries, and at a higher level could be developed into a self-optimising software package, which will enable rapid determination of the key control parameters needed to optimise process performance just in time.

Controlling the thermo-elastic behavior of tooling machines can only be achieved by systematic analysis, characterization and design of their fluidic system. In the first stage of this project, fundamental work was done to develop simulation methods for the calculation of the thermodynamic behavior of a representative example of a milling machine and each of its components. With experimental and numerical data it was proven, that significant improvement can be achieved by a proper design of heat transfer conditions of the fluidic system. To correct and counterbalance thermo-energetic effects, it will be necessary to develop new structures of the tooling machines systems which ensure the temperature-control of local subsystems in dependence of the actual working process. The work which is documented in this paper deals with the thermodynamic behavior of the motor spindle.

Rotating bed reactors are used throughout the process industry. They are usedboth in the chemical industry and other industrial sectors, such as pharmaceuticals and the textile industry in decolorization due to by-products or contaminants.SpinChem AB manufactures rotary bed reactors (RBRs) to perform chemical reactions between liquids and solids. The solid material consists of spherical particles0.1 mm - 1 mm in diameter that are packed between two cylindrical spaces in theRBR. The goal of this project work is to determine the power number, the axial force thatthe RBRn experiences, the torque requirement on the motor and power consumptionof the the RBR when a fully developed turbulent flow is achieved. The purpose ofthe work is to optimize the technology from the energy usage point of view, makethe product simple and easily accessible for chemical and industrial processes as acontribution to the development of sustainable society. In order to achieve the purpose and goal of the projects, Computational Fluid Dynamics (CFD) combined withexperimental models were used. Computation were made in COMSOL Multiphysicsfor two turbulence models. In it, the rotating machinery was used with moving meshtechnique for both the standard k−ε model and the SST k−ω turbulence models.The result is then compared with the empirical models. Investigation were done for two models of the rotating bed reactors (RBRs). Onemodel is called RBR S2 with relatively small size and RBR S14 which is a muchlarger version. For RBR S2 the experimental results turned out to be, an output ofpower number which is 3.4, torque requirement of 0.03 Nm, power consumption of3 W and a thrust force of 0.11 N. While the simulation results turned out to bean output of power number which is about 1.2, torque requirement of 0.013 Nm, apower consumption of 2 W and thrust force of 0.8 N. Similarly, the experimentalresult for RBR S14 was as follows. A power number of 0.53, torque requirement of0.41 Nm, power consumption of 6 W and a thrust force of 4.16 N. The simulationresults turned out to be, a power number of 0.34, torque requirement of 0,40 Nm,a power consumption of 4.14 W and thrust force of 3.61 N. With the help of the calculated power numbers, the power required to rotate theRBR can then be determined. Power number is determined when a fully developedturbulent flow is achieved. For RBRS2, a fully developed turbulent flow is achievedat Re = 2.8·104 and the angular velocity at that Reynolds number is about 830RPM. At that speed, the power is shown to be about 4 W for RBRS2. For RBRS14,a fully developed turbulent flow is achieved at Re = 1.5 · 105 and then the speed atthat Reynols number is about 83 RPM. The power need at that stage is shown tobe about 20 W. / Roterande bäddreaktorer används inom hela processindustrin. De används bådeinom den kemiska industrin och andra industriella sektor såsom, läkemedel och textilindustrin vid avfärgning på grund av biprodukter eller föroreningar. SpinChemAB tillverkar roterande bed reaktorer (RBR) för att utföra kemiska reaktioner mellan vätska och fasta material. Det fasta materialet består av sfäriska partiklar på0,1 mm - 1 mm i diameter som packas mellan två cylindrar i RBRn. Målet med detta projektarbete var att bestämma effekt nummer, effekt som krävsvid det effekt nummer, kravet på vridmoment från motorn samt den axiella kraftensom den roterande bäddreaktorn upplever när ett fullt utvecklat turbulent flöde uppnåtts. Syftet med arbetet var optimera teknologin ur energianvändningssynpunkt, göra den enkel och lättillgänglig för kemiska och industriella processer som ett bidragför hållbar samhällsutveckling. För att kunna uppnå syftet och målet med projekten användes, avancerade beräkningsmetoder i födes mekanik (CFD) i kombinationmed experimentella modeller. Beräkningar gjordes i COMSOL Multiphysics för tvåturbulenta modeller. I de användes roterande maskineriet med en medföljande mesh (moving mesh) för både standard k-ε modellen och SST k-ω modellen. Resultatet jämfördes sedan med de empiriska modellerna. Undersökningarna gjordes för två modeller av RBR. Ena modellen heter RBR S2med relativt små tillstorlek och RBR S14 som är mycket större version. För RBR S2visar den experimentella resultaten ett effekt nummer på 3,4, vridmoment på 0,03Nm, effekt förbrukning på 3 W och en axiellkraft ("thrust force") på 0,11 N. Simuleringsresultatet visar ett effekt nummer på 1,2, vridmoment på 0,013 Nm, effektförbrukning på 2 W och en axiellkraft på 0,8 N. För RBR S14 visade det experimentella resultatet ett effekt nummer på 0,53, vridmoment på 0,41 Nm, effektförbrukning på 6 W och en axiellkraft ("thrust force") på 4,16 N. Simuleringsresultatetvisade att effekt nummer var 0,34, vridmoment på 0,40 Nm, effektförbrukning på4,14 W och en axiellkraft på 3,61 N. Med hjälp av de framräknade effektnummer kan effekten som behövs rotera RBRnbestämmas. Effektnummer bestäms när ett fullt utvecklat turbulent flöde uppnåtts. För RBRS2 uppnås ett fullt utvecklat turbulent flöde vid Re = 2,8·04 och vinkelhastigheten är 830 RPM vid det Reynolds nummer. Effekten som krävs för att drivaRBRn vid det läge är ca 4 W för RBRS2. För RBRS14 uppnås ett fullt utvecklatturbulent flöde vid Re = 1,5·105 och då har vi en hastighet på 83 RPM. Vid denhastighet visas effekten vara ca 20 W.