Papers by Keyword: Efficiency

Abstract: The efficiency of the functioning wireless cellular networks using modern information and computer technologies is analyzed. The constituent technical components of the vector quality of functioning of a wireless network segment in the event of a threat to the security of a telecommunication system and eliminating the threat of vulnerability have been studied. Some aspects information security of wireless cellular networks are considered from the point view of the characteristics information protection system and the reliability of the communication network.

Abstract: In recent years, the textile industry has increased its exports compared to previous years and produces thousands of jobs per year. However, some manufacturing companies in the textile industry experience low efficiency, such as the current textile company under study associated with unplanned machine downtime and idle time. In this sense, this study aims to promote the capacity, productivity, and efficiency of textile companies that manufacture garments. Therefore, a Lean Maintenance model supported by the integration of Lean Manufacturing instruments and techniques such as TPM, 5S, Kaizen is proposed in order to improve machine availability and quality through management metrics. After the implementation of the proposed tool integration, the activities of the operations were standardized, an increase in efficiency was generated, and a favorable change in maintenance metrics was achieved.

Abstract: Performance of solar dryers were tested. In the past, to study the efficiency of solar dryers. A dryer with one drying chamber was built and tested by changing the conditions. In each experiment, the solar irradiance value is different, which can cause the results to be inaccurate. Therefore, in this study, a number of drying chambers are designed according to the number of experimental conditions to be studied during the same period. To reduce factors that will cause discrepancies in the experimental results. The solar dryer with 4 drying chambers was constructed in 1 unit and tested the performance of passive solar dryer (PSD) and active solar dryer (ASD). Air flowrate of ASD varied at 0.03 m³/s (ASD0.03), 0.06 m³/s (ASD0.06) and 0.09 m³/s (ASD0.09). Pork was selected as testing material with initial moisture content of 265% dry basis. Drying rate, solar dryer efficiency and specific energy consumption are criteria to evaluate of solar dryer performance. Result from the experimental was found that the performance of PSD is lowest compared with ASDs. Furthermore, it was revealed that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Results from the experimental reveal the ASDs performance are higher than that of PSD. Moreover, it was found that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Whereas, specific energy consumption of ASD0.06 is lower than that PSD, ASD0.03 and ASD0.09 by 26%, 11% and 9%, respectively. Finally, it was also found that solar dryer efficiency of PSD, ASD0.03, ASD0.06 and ASD0.09 are 11.68%, 13.34%, 14.89% and 13.73%, respectively.

Abstract: One thousand seventy-six million tonnes, or 2,89% of world carbon emissions, result from maritime transportation annually. One of the solutions to tapering down this trend is to create fossil-free renewable energy. Due to weather conditions, wind energy is the potential energy to achieve significant fuel savings. Flettner rotor is feasible for several container carriers with various deadweight tonnage (DWT), rotor dimensions, and efficiency results. This research conducted in the Indonesian Sea uses a parametric calculation to analyze the application of the Flettner rotor in several types of bulk and container carriers with six rotor specifications to minimize carbon emission and optimize the load. This study shows the optimal efficiency of ships after using the Flettner rotor. Flettner rotor can reduce 330.15 kg of fuel in 251,667 DWT of bulk carrier and 559,22 kg on 94,727 DWT container carrier. This study also proves the decrease of carbon emission to 288.86 kg in the bulk carrier and 488.98 kg of carbon emission from the container carrier after using the Flettner rotor. This result of efficiencies can be modified and raised according to the number of installed rotors.

Abstract: Technologies that take advantage of alternative sources, such as Michell-Banki turbines, can improve electric power conditions in rural or non-interconnected areas with low environmental impact, but they need to be further studied to better understand their phenomenology and ways to increase their performance. The numerical evaluation of rotors under specific operating conditions results in efficiency curves for the evaluated prototypes such that devices that take full advantage of the flow conditions of a given location are proposed. Considering the above, the main objective of this work was to design the rotor and the injector of a Michell-Banki turbine and to evaluate it numerically for the conditions of 0.24 m³/s and 18 m of head available at a point with potential energy use in the irrigation district Canal Iguá in Huila - Colombia. The design was made following OLADE recommendations, and the simulations were made utilizing computational fluid dynamics, the k- ω turbulence model was used and the torque was monitored, then the GCI and TCI were calculated to establish the numerical uncertainty of the results. Finally, the numerical curves of efficiency versus rotor speed were created. Both the design and simulation results show that the design is feasible for the operating conditions and meets the expectations of serving for the installation of a 20 kW micro-hydroelectric power plant at the site, but the design predicted an atypically high 86.3% efficiency, while the simulation reported an atypically low 51.8%, being 78% the average reported according to OLADE.

Abstract: Air preheaters are used in thermal power plants to preheat combustion air before it enters the furnace by recovering and using waste heat from the flue gas that is supposed to be exhausted at the stack to reduce the work needed by the furnace to combust fuel and improve the boiler efficiency. Air preheater leakage is the bypassing of the cooler ambient air into the flue gas side, reducing the temperature needed to heat the heating elements which transfers the heat into the air side. This negatively impacts the heat transfer effectiveness of the air preheater and the overall thermal efficiency of the plant. This paper aims to review the effectiveness of the soft touch seals applied in a Ljungstrom Type Regenerative Air Preheater installed in a 455 MW (net) Coal-Fired Thermal Power Plant situated in Mauban, Quezon Province in the Philippines in reducing the air preheater leakage through calculations and analysis in compliance with the ASME Performance Test Code to ensure accuracy and repeatability.

Abstract: This study estimates the relative efficiency of twelve colleges of the University of Sharjah from 2014 to 2019. The methodological approach we employed ensures the homogeneity of the colleges under review. We used an output-oriented smoothed bootstrap data envelopment analysis (DEA) model for the efficiency assessment while assuming that variable returns-to-scale prevail. Output orientation facilitates target-setting rather than cost-cutting, which is supported by input-oriented DEA models. Our analysis indicated an improvement in the efficiency of the University of Sharjah during the period under review. Also, the College of Communication, Engineering, and Law are the most influential benchmarks for the remaining colleges. However, the Colleges of Arts, Humanities & Social Sciences and Business Administration present a definite improvement. Increasing the postgraduate student recruitment is more useful for further efficiency improvement of the University of Sharjah than expanding undergraduate student recruitment.

Abstract: The purpose of this study was to explore airport performance and its impact on customers’ and employees’ satisfaction. This study applied a slacks-based measure network DEA (NSBM) model to evaluate the performance of sixteen international airports. Ten variables were incorporated in the two-stage NSBM model. Specifically, five inputs (i.e., number of employees, number of terminals, number of runways, airport area, and capacity) and three outputs (i.e., number of passengers, number of aircraft movements, and cargo) were used for the first stage. In the second stage, all outputs from the previous stage served as inputs (linking activities), while the outputs of this stage are the perceptions of employees and customers about the work environment and the quality of outputs produced by the first stage, respectively. Drawing on our empirical analysis findings, smaller airports perform better than larger counterparts. In particular, the airports that achieved satisfactory employees’ and customers’ satisfaction scores were those operating a comparatively high number of small-size terminals and have a relatively small number of employees.

Abstract: This study emphasizes the assessment of efficiency and the degree of operating efficiency of mergers and acquisitions in the pharmaceutical industry worldwide. This industry encounters various challenges such as expiring patents, the rise of genetics pharmaceuticals, the entrance of biotechnology companies in the pharmaceutical market, the increasing research and development expenses, government regulations of the pharmaceutical industry, distribution channels, and drug prices. All these challenges result in an intensely competitive environment in which pharmaceuticals suffering from shortcomings (e.g., operational and/or financial inefficiencies) are not easy to catch up with the competition. Mergers and acquisitions are major activities to overcome shortcomings and achieve growth. Mergers and acquisitions have been widely used in the pharmaceutical industry for many years and are expected to accelerate. The objective of this work is to identify whether mergers and acquisitions between pharmaceutical companies can be successful and to highlight the most favourable consolidations. The assessment of mergers and acquisitions is realized through conventional and stochastic data envelopment analysis approaches. The empirical analysis draws on a sample of 371 pharmaceutical companies. The original sample was extended by 870 possible combinations between firms. Our empirical analysis reveals a positive impact of mergers and acquisitions on the efficiency of pharmaceutical companies.

Abstract: This study measures the sustainable performance of ten car manufacturers operating in the U.S. We took into account three dimensions of sustainability: (a) economic, (b) environmental, and (c) social. Our methodology drew on the generalized directional distance function data envelopment analysis in conjunction with the multi-parametric method for bias correction of efficiency estimators. The combination of the two methods reduced the bias of efficiency estimators, which was sourced from the dimensionality of the production set and the sample size. Our analysis revealed that Chrysler-Fiat, GM, and Ford have the worst sustainable performance among firms under review over the years 2014–2018.