A piezoelectrically actuated valveless micropump has been designed and developed. The principle components of this system are piezoelectrically actuated (PZT) metal diaphragms and a complete fluid flow system. The design of this pump mainly focuses on a cross junction, which is generated by a nozzle jet attached to a pump chamber and the intersection of two inlet channels and an outlet channel respectively. During each PZT diaphragm vibration cycle, the junction connecting the inlet and outlet channels with the nozzle jet permits consistencies in fluidic momentum and resistances in order to facilitate complete fluidic path throughout the system, in the absence of any physical valves. The entire micropump structure is fabricated as a plate-by-plate element of polymethyl methacrylate (PMMA) sheets and sandwiched to get required fluidic network as well as the overall device. In order to identify the flow characteristics, and to validate the test results with numerical simulation data, FEM analysis using ANSYS was carried out and an eigenfrequency analysis was performed to the PZT diaphragm using COMSOL Multiphysics. In addition, the control system of the pump was designed and developed to change the applied frequency to the piezoelectric diaphragms. The experimental data revealed that the maximum flow rate is 31.15 mL/min at a frequency of 100 Hz. Our proposed design is not only for a specific application but also useful in a wide range of biomedical applications.

This paper presents the design and simulation of MEMS based piezoresistive pressure sensor for microfluidic applications. Geometrical parameters are very much considerable when designing microstructure of the pressure sensor. Hence, an analysis is carried out by changing the dimensional parameters of three different diaphragm geometries namely square shaped diaphragm, circular shaped diaphragm and cross sectional beam shaped diaphragm respectively. This is performed in three dimensional mesh plots using Matlab. The Finite Element Method (FEM) analyses are performed in COMSOL and by comparing the results, the square type diaphragm is chosen as best diaphragm geometry for the microfluidic applications. In addition, modal analysis is carried out by using Ansys to identify the natural frequency of the best diaphragm geometry. Also Piezoresistive sensing elements are designed and simulated by performing coupled field analysis using COMSOL Multiphysics. Simulation results reveal that piezo resistive square type pressure sensors have high sensitivity in a wide range of pressures.

This paper presents the design and fabrication of a domestic biogas unit by using daily organic waste for cooking. Basically, this unit consists a gas storage unit and a digester barrel. Initially, the organic wastes including kitchen wastes were deposited into the digester barrel which contains water with pH 6 once in every two days for two weeks. Then the mix started to produce biogas when the pH value reached around 6.8-7.5. After that food wastes were added slowly every day. When this step is continued further, the daily collection of biogases is 50 liters. As the digestate of this anaerobic digester is rich in nutrients this is also a good organic fertilizer for plants in the home garden. Also, this unit is designed and fabricated with easy maintenance and usage. Further, it is very much beneficial to dispose biodegradable kitchen wastes in an eco-friendly manner. In order to answer the energy demand in domestic level, it is highly essential to utilize the daily organic waste as a source of energy and produce methane as an alternative solution for cooking-energy requirement.

This paper presents the impingement flow study on the temperature profile perforated plate. Icing is one of the most hazardous threats in aviation and this leads to unsafe flight conditions. Hence, thermal anti-Icing is very much useful in aircraft to prevent ice accretion on the surface. On the other hand, the hotspot temperature of this technique might destroy the Aluminum-based Bias Acoustic Liner (BAL) plate. Thus, it is highly essential to study the hotspot temperature profile on the perforated plate. This study is concerned with a numerical study of the convective heat exchange between an impinging air jet at temperatures of 70 °C and a structured perforated surface using the Fluent tool. The model is designed in an Aluminium plate with the dimensions of 100 mm x 100 mm x 1mm containing 0.15 cm diameter perforated hole. In addition, the 0.25 cm diameter circular nozzle is maintained at a constant jet-to-target distance of 3.71 cm. In this sense, the standard k-ω turbulence model jet equation is applied to this three-dimensional domain with periodic boundary conditions for the Reynolds numbers ranges from 2000–9000. The simulations are performed based on the gap between two holes and the hole configuration (tandem and staggered) at different jet velocities. The simulation results reveal that there is a rapid increment in heat transfer with Reynolds number and the maximum local Nusselt number decreases by seven and increases to 24 when the Reynolds number varies from 2508.17 to 8778.588 at the surface of the perforated plate. The findings of the hole arrangement on the perforated plate indicate that the tandem hole configuration without a center hole is highly recommended for bias acoustic liners than the staggered configuration. Since the tandem hole arrangement has higher dimensionless temperature, a thicker high temperature layer will be developed at the outer surface. Hence, this kind of perforated plate is more suitable to prevent ice accretion in aircraft applications.