Abstract: Wind energy is the most rated source of renewable energy in the present world. But it is not feasible to extract this form of energy everywhere due to the variation of wind speed. In Bangladesh, Rajshahi city, in particular reveals that the average wind speed is below the cut-in-wind speed. So, it is difficult to generate electricity. The main goal of this work is to perform a structural analysis of a light wind turbine blade so that it can rotate in lower wind speed. Light blades can move faster and increases the rpm. The mechanical efficiency of the wind turbine depends on rpm. The maximum mechanical efficiency of about 35% has been obtained from this work.
Abstract: This paper explains the concept of semantic stability as a missing link between cognition and behavior for multi-robot cooperation with distributed sensing. In cooperation perspective when the cognition of robots is different, there need to interpret the situation by selecting a common Region of Interest. Interpretation of situation by observing visual information is still challenging for the artificial agents. The reason behind this difficulty is to find the cognitive boundary by which the situation can be described efficiently. Since this boundary is a part of cognition, therefore this research relates this boundary with region of interest (ROI) to visualize this concept. In this regard, this boundary contains semantic relevant objects which build a connection between visual objects and their semantic interpretation by semantic labelling. This paper addresses various related technical issues to emphasize the emergence of this concept. A formal expression for the semantic stability concept has been proposed in the current work and applies it to determine the cognitive boundary by selecting the best ROI from the visual scenes. However, selecting of best ROI is meaningless, since the cognition of individual robot is different. Therefore, for co-operation, best ROI needs to be shared between robots. In this research, ROI sharing gives various behaviors which are guided by semantic stability concept. In this respect, semantic stability acts as a missing link between cognition and behavior by selecting meaningful ROI for Cognition and decision making to perform actions which stands as Behavior in a cooperation task. Several complex scenes are tested to illustrate the applicability of the proposed algorithm at the end of the paper.
Abstract: A virtual impactor has been characterized analytically to separate small (micro range) aerosol particles. In the
current study, an approximate analytical expression relating to the collection efficiency and mean aerodynamic
diameter of particles collected has been developed, Three sets of design parameters have been studied to
investigate the effects of changes in solution concentration, collection probe diameter, nozzle diameter and the
distance between them to the particle size and collection efficiency. Effects of major flows and minor flows
have also been presented. It was found that, increasing solution concentration and decreasing the total flow
rates, increased the particle mean diameter rapidly in the minor flow. But the interesting part is that, the particle
mean diameter increased to a lesser extent as the rest parameters were increased
Abstract: This paper describes an approach to detect the Region of Interest (ROI) in Video Frames where different objects are related with dynamic interaction. A mathematical frame work for determination of the ROI by formulating dynamic interaction in various contexts has also been proposed. This paper introduces a new methodology of evaluating ROI which reflects human psychology of cognitive vision. Various experiments are presented to illustrate the proposed method which gives exciting and promising results.
Abstract: An analytical study has been conducted to determine the physical dimensions (i.e. height and diameter) of a cylindrical aerosol generation chamber in which an atomizer is presumed to generate poly-disperse aerosol from a certain solution. The chamber considered here is both structurally and operationally different from most of the collection devices (e.g. gravitational settling chambers, centrifugal separators, wet scrubbers, filters, electrostatic precipitators etc. reported in the literatures. Expressions for cut-off droplet diameter and subsequently for the velocity and particle displacement history inside the chamber have been developed in this study. For a particular cut-off aerodynamic diameter the motion of the droplets has been realized to be affected by the fluid velocity through the chamber and whether the droplets are in Stokeâs region or not. Finally, it has been concluded that, chamber height is to be determined by the maximum height reached by the largest droplet produced by the atomizer whereas its diameter is determined by fluid velocity within the chamber when atomization pressure and particle cut-off aerodynamic diameter are known. Several experimental results for the same configuration have been found in good agreement.
Abstract: The renovation of biomass solid waste in the form of mahogany (Swietenia macrophylla) seed into bio-fuel as well as activated carbon by fixed bed pyrolysis reactor has been taken into consideration in this study . The mahogany seed in particle form was pyrolysed in an enormously heated fixed bed reactor with nitrogen as the carrier gas. The reactor was heated from 4000C to 6000C using a external heater in which rice husk and charcoal were used as the heater biomass fuel. Reactor bed temperature, running time and feed particle size have been varied to get the optimum operating conditions of the system. The parameters were found to influence the product yields to a large extent. A maximum liquid and char yield were 49 wt. % and 35 wt. % respectively obtained at a reactor bed temperature 5000C when the running time was 120 minutes. Acquired pyrolyzed oil at these optimal process conditions were analyzed for some of their properties as an alternative fuel. The oil possesses comparable flame temperature, favorable flash point and reasonable viscosity along with somewhat higher density. The kinematic viscosity of the derived fuel is 3.8 cSt and density is 1525 kg/m3. The higher calorific value is found 32.4 MJ/kg which is significantly higher than other biomass derived fuel. Moderate adsorption capacity of the prepared activated carbon in case of methyl blue and tea water was also revealed.
Abstract: Chronological demand on fossil fuel has forced researcher to explore alternative sources of energy to
ensure the existence of human being. But, one important aspect which has been unnoticed, is attempting to
recover the exhaust energy which is being wasted from many of the existing power systems. This case study
attempts to recover waste heat exhausted and hence to generate process steam from a gas engine of 8.5MW
capacity at a power plant named âEverest Power plantâ located at Narayangonj, Bangladesh which supplies
power to âFresh Group of Industriesâ. Recovered heat is supposed to be used to produce process steam that
is to be supplied to a nearly located chemical industry named âTasnim Chemical Industryâ. Total cost of heat
recovery system has been estimated on the basis of a simple design. The result illustrated that from the
existing gas engine operating at full load and exhausting heat at temperature 4180C, the steam production
rate is to be around 5.78 tones per hour with a smoke tube heat recovery steam generator pinch point of
350C. The plant overall efficiency has also been predicted to be improved to 70.43% from the existing
overall efficiency of 46.07%. Acost estimation has been carried out at the end. The specific cost of process
steam was found to be 178 BDT/tonne which is far below than that of oil fired boiler of 570 BDT/tonne. To
develop the proposed exhaust heat recovery system in the noted plant is therefore strongly recommended.
Abstract: In many industrial instances product quality is determined, in large part, by color consistency of the product. Therefore it has been proven to be very useful now-a-days in many industrial circumstances. Unfortunately, color inconsistency of a product appears very frequently in the course of continuous production of an automatic system. These phenomena become the cause of not only defective items but also damage the manufacturerâs reputation. Numerous techniques for maintaining color consistency of the product have been proposed during several past decades. Truly speaking, most of those techniques involve expensive and rarely found devices. Taking these aspects into consideration, a preliminary effort has been put hereby on the automatic color detection system by using LDR circuit which was expected to be very effective to real time detection and eventually to elimination of the defective product from the production line. This research involves both electrical and mechanical equipments namely a D.C. motor to drive the conveyor belt, a solenoid coil to guide the push bar, a LDR circuit to identify the color of the product, an adapter for D.C. supply etc. By the virtue of the designed system it is confirmed that no defective product with color inconsistency goes to the customerâs hand. Finally it should be noted that, all the components used in this system are readily available with low cost. Considering all aspects, it is concluded that the designed system has greater reliability and ease of maintenance that makes the system more promising in modern industrial application.
Abstract: Bangladesh suffers from chronic shortage of electricity and gas. At present, the electricity situation is so bad that at peak hours (5-10 p.m.) approximately 600 MW of load shedding is required. The unreliable electricity has been directly linked to loss of productivity, and hence to lowering of economic growth rate. Due to her crisis in the energy sector Bangladesh is thinking of more renewable sources of energy. Despite being blessed with a fertile soil for agriculture, Bangladeshâs food and agricultural outputs, given by gaps between the strong demand and supply energy, especially for diesel fuel and electric power for irrigation, suffers drastically, in all areas in general and in the draught areas of the northern districts - the Barind areas of Bogra, Rajshahi, Rangpur, Dinajpur, Chapai Nawabganj and other districts of Northern Region. A study has been made to find out the feasibility study if replacing diesel pumping by solar pumping and installation of new solar pumping for mitigating the crisis of water for irrigation. Daily average solar radiation varies 4 to 6.5 kWh per square meter. A financial analysis is also made to realize the Prospects of Solar Pumping System in the northern Region of Bangladesh.
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