Papers by Keyword: Performance Evaluation

Abstract: The study presents the design of a highly efficient cooking stove for rural applications, along with performance evaluation. Drawing on diverse literature, existing works were analysed to derive design enhancements. Utilizing SolidWorks and Creo, a model was constructed, followed by material selection and cost analysis using accessible market components. ANSYS Fluent enabled flow analysis for both optimal and real configurations, complemented by experimental tests for validation. Results underscore the stove's efficiency, evident in reduced wood consumption for cooking and decreased soot generation. Significantly, the system's heat transfer rate reached 11.67°C/min, outperforming open stoves at 3.42°C/min, while maintaining affordability at RM 415.34. Nomenclature = Temperature transfer efficiency for heat recovery = Temperature outside air before entering system = Temperature inside air after system heat transfer has occurred = Temperature inside air before system is switched on = Temperature Transfer Efficiency for Heat Loss

Abstract: The main disease manifestations of bridge deck pavement are fatigue cracks and rutting deformation. This paper compares and analyzes the performance of traditional asphalt mixture, styrene butadiene styrene (SBS) modified asphalt mixture, epoxy resin (EP) modified asphalt mixture and high durability asphalt mixture (HDAM) applied to bridge deck pavement through laboratory tests. The results show that the fatigue life of EP modified asphalt mixture and HDAM is about 2.3 times and 3.4 times that of matrix asphalt mixture. EP modified asphalt mixture has better high temperature stability, and HDAM has higher low temperature resistance and water damage resistance. It can be used for reference in different service areas.

Abstract: We evaluate and compare the static and dynamic performances of four different 4H-SiC power MOSFETs (Conventional DMOS and UMOS, Superjunction (SJ) DMOS and UMOS FETs) from 0.6 to 10kV. The static on-state performance is determined by analytically calculating the specific on-resistance (R_ON,sp), while the dynamic switching performance is determined by extracting the specific gate charge (Q_G,sp) and switching energy loss per cycle (E_sw,cycle) using 2D device simulations. It has been found that the SJ UMOS FET exhibits at least a 31% (up to 53% at 0.6kV) reduction in the R_ON,sp · Q_G,sp Figure-of-Merit (FoM) compared to the SJ DMOS FET within the breakdown voltage rating range studied.

Abstract: The stationary thresher machines are widely used worldwide in threshing and separating many crops; they proved to have a high performance, especially in small spaces. The threshing drum is the essential working device of the thresher and plays a fundamental role in threshing efficiency, consumed specific energy, machine productivity, and seeds loss. In this study, a structure of sunflower thresher (open style drum with 45 incline degree loop teeth) was tested, and evaluated for performance under different drum rotational speeds (150, 200, 250, and 300 rpm) and different concave clearances ( 10, 15 and 20 mm). The thresher structure and operating parameters were assessed and optimized concerning damaged and unthreshed seed percentage, threshing efficiency, consumed specific energy, and machine productivity. The obtained results revealed that increasing cylinder rotating speed positively related to threshing efficiency, power requirements, and machine productivity while increasing concave negatively related to threshing efficiency, power requirements, and machine productivity. The highest efficiency of 97.40 %, the maximum productivity of 434.50 kg/h, and the lowest consumed specific energy of 6.85 kW.h/t were obtained at the operational condition of 300 rpm drum rotational speed 10 mm concave clearance. Buckingham's π theorem was followed to find an equation to predict the threshing efficiency theoretically, resulting in an equation with an R2 value of 0.8892. These developments were an excellent choice to uprising the performance of the original thresher drum.

Abstract: In this paper we consider the Multi-Aisle Automated Storage and Retrieval Systems where only one Storage/Retrieval machine (crane) is used, which has the advantage of decreasing the system costs but at the same time has the disadvantage of reducing the system throughput. This important performance evaluation parameter is highly related to another equally important one i.e. the cycle time of the crane. Because of its repercussions on the whole system performances, we are interested here in the modeling of this average cycle time, knowing that it could bring positive and significant advantages in terms of efficiency and accuracy, and consequently throughput and productivity. For that, the system to be studied is considered as Discrete Events System. To model it, we use a dedicated graphical tool known under the name Timed Petri Nets in the purpose to explore the theory used to evaluate the performances of these systems.

Abstract: Porous asphalt pavement is widely used in domestic engineering, whose repair technology is still a problem in engineering application. Rut specimens for porous asphalt pavement are made, so the actual repairing condition of porous asphalt pavement can be simulated after slotting and repairing by open-graded cold mend material. In addition, the repair efficiency of open-graded cold mend material was verified. The results of the pullout test show that when the spraying dosage is 0.75L/m², the bond behavior of bonding oil is best excellent. The Accelerated Loading Facility (ALF) indicated that the cold mend material has favorable abrasion resistance properties, and the abrasion resistance is less effected by the spraying dosage of bonding oil. Meanwhile, it’s reveled that the permeability coefficient of rut specimen repaired by cold mend material decreases with the increase of spraying dosage of bonding oil in the permeability test, and too much bonding oil will seriously affect the rut specimen’s original permeability.

Abstract: Maintenance management is an orderly procedure to address the planning, organization, monitoring and evaluation of maintenance activities and associated costs. The maintenance management allows to have an efficient tool either to the management of the preventive or curative activity, an optimization of the production tool, and finally a follow-up of the costs and the performances. A good maintenance management system can help prevent problems and damages to the operating and storage environment, extend the life of assets, and reduce operating costs.In this paper, we will first present our model on the joint management of spare parts and maintenance. We will do a simulation study of our model, presented in the first section of this paper. The results of this study are presented in the second section through the presentation of the influence of certain parameters of the model on the operation of the system under consideration. This study carried out on the graphical interface of Matlab, which is one of the performance evaluation techniques. It allows to visualize the variations and anomalies which can be reached in the system considered as an overcoming of the repair of the machines by the unforeseen breakdowns.

Abstract: The rising awareness of the importance of moringa seeds has geared interest in its mass production. A major step in making the seed available for it vast usage is shelling. Most rural farmers of moringa seed use the traditional methods of shelling. These methods are tedious, time consuming with attendance low outputs that produce unhygienic products. The need to develop appropriate machines and equipment for processing of moringa seeds become necessary. This work developed a moringa seed shelling machine using available local materials. The development of the shelling machine was based on engineering mechanics of impact and shearing forces. The machine consists of a hopper, shelling unit, shafts, cleaning unit, sieve, discharge unit, power transmission unit and frame. The machine was evaluated based on variation in speed and feedrate to obtain the shelling efficiency, throughput capacity and percentage seed damage at 14% (d.b) moisture content powered by a 0.75 kW electric motor. The results obtained show that the machine has the highest shelling efficiency of 72.72% at 60 g/min feedrate with a throughput capacity of 8.31 kg/hr and the minimum percentage seed breakage of 2.22%. Machine speed of 250 rpm favoured the smooth operation and performance of the machine. The machine is very useful for rural people, farmers and small scale industries for post-harvest processing of moringa seeds since it cost and operational principle is within their technical know-how and capability.

Abstract: The authors have continuously studied buckling-restrained braces using steel mortar planks (BRBSM). The performance of energy absorption and fatigue against cyclic loading has been evaluated. Although past studies have clarified the structural performance of BRBSM as single member, it is necessary to study not only the performance of BRBSM as single member but also the performance of BRBSM installed in a building structure. In this paper, a frame model of mid-rise steel structure with BRBSM subjected to earthquake motions with various characteristics is analyzed. Comparing the results of the analysis and the past tests, the seismic behavior of a structure is discussed. Especially, the seismic performance of BRBSM installed in the building structure is evaluated. In addition, the seismic performance of two types of BRBSM; basic and developed high-performance types, is compared and evaluated about cumulative plastic strain energy ratio and cumulative fatigue. As a result, the performance capacities of the both types of BRBSM exceed the required values of BRBSM under severe earthquake motions about cumulative plastic strain energy ratio and cumulative fatigue. The basic-type BRBSM has the fatigue capacity against 2 to 5 times severe earthquake motions. The required values of high-performance-type BRBSM are about a half of accumulated fatigue capacity compared with the basic-type one. The high-performance-type BRBSM is applicable against quite many cyclic loadings of low strain amplitude, and able to be used for long-term service.

Abstract: In the field of impact engineering, high-speed impact phenomena are simulated using a projectile accelerator. At the Impact Engineering Laboratory in Ritsumeikan University, a single-stage gas gun was designed to investigate the high-speed penetration phenomena of impacts in sand, which is known to show fluid-like behavior. The gas gun consists of a 2 m launch tube that can achieve projectile muzzle velocities of up to around 500 m/s. The theoretical muzzle velocity of the projectile can be calculated by considering the speed of sound and the specific heat ratio of propellant gases. A performance evaluation for high-pressure ranges of 1 MPa and higher in a high-pressure vessel has been conducted. When fitting parameters are introduced to the theoretical formula, good agreement is obtained with the experimental results. In this study, experiments for low pressure ranges were conducted to predict the projectile velocity and to investigate the minimum velocity limit of the projectile. By introducing fitting parameters to the theoretical formula, the projectile velocity could be predicted accurately for pressure ranges less than 1 MPa. Furthermore, the minimum velocity limit of this equipment was found to be around 30 m/s.