Three-Dimensional Electrode Integration with Microwave Sensors for Precise Microparticle Detection in Microfluidics

Microwave sensors integrated with microfluidic platforms can provide the size and permittivity of single cells and microparticles. Amongst the microwave sensor topologies, the planar arrangement of electrodes is a popular choice owing to the ease of fabrication. Unfortunately, planar electrodes generate a non-uniform electric field which causes the responsivity of the sensor to depend on the vertical position of a microparticle in the microfluidic channel. To overcome this problem, we fabricated three-dimensional (3D) electrodes at the coplanar sensing region of an underlying microwave resonator. The 3D electrodes are based on SU8 polymer which is then metallized by sputter coating. With this system, we readily characterized a mixture composed of 12 um and 20 um polystyrene particles and demonstrated separation without any position-related calibration. The ratio of the electronic response of the two particle types is approximately equal to the ratio of the particle volumes, which indicates the generation of a uniform electric field at the sensing region. The current work obviates the need for using multiple coplanar electrodes and extensive processing of the data for the calibration of particle height in a microfluidic channel: as such, it enables the fabrication of more sophisticated microwave resonators for environmental and biological applications

Solution Processed Organic Solar Cells: Fabrication and Laser Structuring

crisis present in the world. solution processing of such devices allows large scale production using roll-to-roll process and similar fabrication processes. Lasers can be used for selective ablation of different layer of such solar cells for structuring. This work aimed at fabricating flexible polymer solar cells with all layer processed from solution as well as investigating the effect of laser for structuring different layer of the solar cells fabricated. To fabricate the solar cells, well-established photoactive blends from poly-(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61-butyric acid methyl ester (P3HT:PC61BM) was used. The solar cells were comprised of solution processed silver as cathode and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) as anode while zinc oxide (ZnO) was used as electron transport layer. An infrared laser was used to structure different layers of the solar cells and assess the effect on the layers. For fabrication, different layers were processed by lab-scale solution-based techniques such as doctor-blading, horizontal dipping and spin coating. Processing parameters for fabricating each layer were optimized experimentally and the solar cell fabricated with optimal parameters showed reasonable power conversion efficiency. Also, the analysis of structuring different layer of solar cells using an infrared laser is presented

Solution Processed Organic Solar Cells: Fabrication and Laser Structuring

crisis present in the world. solution processing of such devices allows large scale production using roll-to-roll process and similar fabrication processes. Lasers can be used for selective ablation of different layer of such solar cells for structuring. This work aimed at fabricating flexible polymer solar cells with all layer processed from solution as well as investigating the effect of laser for structuring different layer of the solar cells fabricated. To fabricate the solar cells, well-established photoactive blends from poly-(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61-butyric acid methyl ester (P3HT:PC61BM) was used. The solar cells were comprised of solution processed silver as cathode and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) as anode while zinc oxide (ZnO) was used as electron transport layer. An infrared laser was used to structure different layers of the solar cells and assess the effect on the layers. For fabrication, different layers were processed by lab-scale solution-based techniques such as doctor-blading, horizontal dipping and spin coating. Processing parameters for fabricating each layer were optimized experimentally and the solar cell fabricated with optimal parameters showed reasonable power conversion efficiency. Also, the analysis of structuring different layer of solar cells using an infrared laser is presented

Solution Processed Organic Solar Cells: Fabrication and Laser Structuring

crisis present in the world. solution processing of such devices allows large scale production using roll-to-roll process and similar fabrication processes. Lasers can be used for selective ablation of different layer of such solar cells for structuring. This work aimed at fabricating flexible polymer solar cells with all layer processed from solution as well as investigating the effect of laser for structuring different layer of the solar cells fabricated. To fabricate the solar cells, well-established photoactive blends from poly-(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61-butyric acid methyl ester (P3HT:PC61BM) was used. The solar cells were comprised of solution processed silver as cathode and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) as anode while zinc oxide (ZnO) was used as electron transport layer. An infrared laser was used to structure different layers of the solar cells and assess the effect on the layers. For fabrication, different layers were processed by lab-scale solution-based techniques such as doctor-blading, horizontal dipping and spin coating. Processing parameters for fabricating each layer were optimized experimentally and the solar cell fabricated with optimal parameters showed reasonable power conversion efficiency. Also, the analysis of structuring different layer of solar cells using an infrared laser is presented

Techno-economic and environmental feasibility analysis of solar industrial process heating systems in textile industries of Bangladesh

Taking into account the energy crisis and concerns about the effect of burning fossil fuels on the environment, the utilization of renewable energy technologies is being promoted extensively. Despite having significant potential, the feasibility of utilizing solar thermal energy as industrial process heat in Bangladesh is yet to be assessed and this paper aims to fill this research gap. In current work, the viability of utilizing solar thermal energy in Bangladesh for industrial process heating is investigated by parametric analysis considering thermal, economic, and environmental factors. Effect of mass flow rate and inlet temperature on overall heat loss coefficient is studied. The heat gain with respect to the available area for different mass flow rates is presented which can be used as a guideline to determine the capacity of an installed system. A case study is presented for an operational textile factory in Mymensingh to realize the potential of solar industrial process heat using flat plate solar collectors. Energy savings might reach up to 14.7% in summer and around 9% in winter which also leads to reduction of CO2 emission to the same percentage. The payback period has been found to be 13.58 years

Application of nanofluid in heat exchangers for energy savings

Nanotechnology is a promising field in sustainable energy to reduce the energy consumption for optimum design of heat exchangers. Nanofluid provides significant improvement of thermo-physical properties and augmentation of heat transfer coefficients as well as reduces the pumping power if properly selected. In this chapter a CFD simulation using a finite volume method is presented for investigation of the hydrodynamic and thermal behavior of nanofluid flowing through a circular tube of heat exchanger with constant heat flux under single-phase turbulent flow condition for Reynolds number from 4000 to 20,000. Three different nanoparticles (AlO, CuO, and TiO) with different volume fractions (1-5%) dispersed in water are analyzed. The heat transfer coefficient and pumping power increase with the increase in both the Reynolds number and volume fraction. The maximum saving of pumping power at a particular heat transfer coefficient has been obtained at 2% volume fraction for AlO-water and TiO-water nanofluid and at 3% volume fraction for CuO-water nanofluid

Drag-based aerodynamic braking system for the Hyperloop: a numerical study

The Hyperloop promises to revolutionize the transport infrastructure of the 21st century by reducing travel time and allowing people to reach transonic speed on land. It carries with it the hope of a sustainable transportation system during an era of global energy crisis. Overall passenger safety in a high-speed pod necessitates a reliable braking system. This paper introduces the possibility of utilizing aerodynamic drag in the Hyperloop, anticipated to operate at high Mach and low Reynolds flow regime, to attenuate the speed of the pod. Numerical analysis was conducted to investigate the effect of incorporating an aerodynamic brake at different pod velocities (100, 135, and 150 m/s) and deployment angles (30°, 45°, 60°, and 90°). A detailed comparison between the proposed aerodynamic braking system (AeBS) and existing braking systems for the Hyperloop has been presented in this paper. The results demonstrate an increase in drag value of the pod by 3.4 times using a single 0.15 m2 brake plate. When the brake plate was fully deployed at a pod velocity in excess of 112 m/s, the aerodynamic drag-based braking systems was shown to be more effective than the contemporary eddy current braking system.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Economic Challenges of Hybrid Microgrid: an Analysis and Approaches for Rural Electrification

7th Bangladesh-Society-of-Mechanical-Engineers (BSME) International Conference on Thermal Engineering (ICTE) -- DEC 22-24, 2016 -- Bangladesh Univ Engn & Technol, Dhaka, BANGLADESHWOS: 000412828600043This paper focuses on the integration of three renewable resources: biogas, wind energy and solar energy, utilizing solar PV panels, a biogas generator, and a wind turbine, respectively, to analyze the technical and economic challenges of a hybrid micro-gird. The integration of these sources has been analyzed and optimized based on realistic data for a real location. Different combinations of these sources have been analyzed to find out the optimized combination based on the efficiency and the minimum cost of electricity (COE). Wind and solar energy are considered as the primary sources of power generation during off-peak hours, and any excess power is used to charge a battery bank. During peak hours, biogas generators produce power to support the additional demand. A business strategy to implement the integrated optimized system in rural areas is discussed.Bangladesh Soc Mech Engineer

Heat transfer and pumping power using nanofluid in a corrugated tube

Heat transfer enhancement using nanofluid through a plain pipe or corrugated plate has been investigated by many researchers during the last few years. Despite of this improvement, it has not been studied with the justification of using aluminum oxide nanofluid in a corrugated channel in terms of the increased power needed for the flow due to the change in thermophysical properties of nanofluid compared to that of the basefluid. In the present study, the use of nanofluid in a V-shaped corrugated tube for a turbulent flow in order to enhance the heat transfer rate and corresponding pumping power required has been analyzed for Reynolds number-4000 to 20000. For a constant heat transfer coefficient of 10000 W/mK, the minimum pumping power is obtained for 3% volume fraction of nanofluid flowing through corrugated pipe which is 40% lower than that of water

Energy Efficient Hybrid Dual Axis Solar Tracking System

This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanical single axis to a hybrid dual axis. For optimizing the solar tracking mechanism electromechanical systems were evolved through implementation of different evolutional algorithms and methodologies. To present the tracker, a hybrid dual-axis solar tracking system is designed, built, and tested based on both the solar map and light sensor based continuous tracking mechanism. These light sensors also compare the darkness and cloudy and sunny conditions assisting daily tracking. The designed tracker can track sun’s apparent position at different months and seasons; thereby the electrical controlling device requires a real time clock device for guiding the tracking system in seeking solar position for the seasonal motion. So the combination of both of these tracking mechanisms made the designed tracker a hybrid one. The power gain and system power consumption are compared with a static and continuous dual axis solar tracking system. It is found that power gain of hybrid dual axis solar tracking system is almost equal to continuous dual axis solar tracking system, whereas the power saved in system operation by the hybrid tracker is 44.44% compared to the continuous tracking system