Papers by Keyword: Efficiency

Abstract: The article presents the results of researching efficiency of different modes of superplasticizer introduction in solution mixture with different consistency - from hard to plastic. The following methods of superplasticizer introduction into cement were researched: co-grinding of superplasticizer with cement, mixing cement with superplasticizer in dry state, introduction of superplasticizer into cement with mixing water, evaluation of water reduction effect of an additive depending on the methods of its introduction into cement and the time of determining its consistency. It is established that the most efficient method of superplasticizer introduction into plastic mixture is its co-grinding with cement.

Abstract: Many studies of hydrocyclones have confirmed that increasing the feed-flow rate results in a higher separation efficiency. The purpose of this study was to investigate the separation efficiency for a 100 mm solid–liquid hydrocyclone with 1 and 2 wt% solid concentrations at feed-flow rates of 2, 3, 4, 5 and 6 m³/hr. The solid concentration and particle size distribution were analysed using drying–weighing and a particle-size analyser (Mastersizer 2000), respectively. The experimental results indicated that an increase in feed-flow rate from 2 to 4 m³/hr produced decreased separation efficiency. However, when the feed-flow rates increased from 4 to 6 m³/hr, the separation efficiency increased. Furthermore, the higher the feed-flow rate, the smaller the cut size. A novel separation efficiency equation in terms of the concentration ratio and flow ratio is also proposed.

Abstract: Paper presents some investigations, concerning simulation of the nickel based alloy machining. The aim of the research was an optimization of the cutting data for the purpose to increase the machining efficiency and stabilization of the tangential component of the total cutting force at the assumed level. A dedicated physical material model was built and then included to the simulation strategy. Authors demonstrated the influence of the feed rate optimization on the tangential component of the total cutting force value changes and the chip area and in this way the improvement of the cutting process.

Abstract: The model of linear drive with redundant actuation and control system is designed to compare the energy efficiency of the different actuation type. The redundant actuation control system is optimized to increase the energy efficiency of the entire drive. Calculation with this model compares consumed electricity for each drive topology. The results can be used in the design of energy-efficient production machinery and equipment, which is the area of interest of so-called Ecodesign.

Abstract: Fuel-power supply systems are priority areas of engineering services. They account for large capital investments and costs of energy resources. An energy supply system based on LPG provides a high level of diversification and autonomy. This article presents recommendations for determining the basic technological parameters of liquefied petroleum gas tanks. The recommendation are intended to improve the efficiency of the tanks. The economic-mathematical model of optimizing underground tanks considers own evaporative capacity of tanks, their mutual thermal effect, as well as the temporal dynamics and unstable cost factors. The model allows for revealing the optimum technological parameters of installations: a single tank volume, the number of tanks in a group installation, the calculated level of gas tanks fill up before next refueling, depending on the volume of gas consumption.

Abstract: This paper considers the bicriteria scheduling problem of minimizing the composite function of total tardiness and total flow time on single machine with non-zero release dates. The problem is strongly Non Polynomial (NP). Thus, two heuristics SA7 and SA8 were proposed to solve the problem. The generalized algorithm and the branch and bound procedure were also implemented. The four solution methods were tested on a total of 800 randomly generated problems ranging from 5 to 1000 jobs. Results based on effectiveness and efficiency show that the SA7 heuristic is the most suited solution method to solve the problem.

Abstract: This paper synthesizes the results of a research study concerning the use of thermal rehabilitation solutions for single family homes achieved with eco-sustainable, natural and efficient materials.These solutions are aimed mainly at people living in rural areas, who have the ability to execute these works themselves using local materials, often considered to be waste, which are discarded or burned.The research has involved a case study carried out on an old building, with special attention given to natural thermal insulation materials – straw, wool, wood shavings, clay, lime, used in various forms, compositions and application solutions.Combined methods of in situ and laboratory research have been used in order to determine the thermo-physical state and behavior of the thermal insulation solutions made with thermally efficient natural materials available locally.The study has sought to emphasize the durability of natural materials under actual exploitation conditions based on a comparative analysis between the state parameters of the buildings and constituent materials, correlated with conditions of comfort, hygiene, health and thermal energy efficiency.The conclusions of this research yield a usage model for traditional, natural materials based on instructions, and usage and exploitation rules, which take advantage of the building tradition as well as of the new knowledge elements, allowing for the development of a built fund with local, renewable resources and with the least possible expenses.

Abstract: Abstract.In order to ensure higher accuracy and better electrical performance of large antennas in future,this paper does some research for deformation of antenna’s reflector:modeling for 25m antenna and reappearing deformation when elevation changes every 15° just considering gravity by using ANSYS.Using results of simulation obtains deformation error curves with elevation changes, creates the conditions for compensating distortion and has a certain value. By using Ruze formula, deeply studies the regular about antenna’s electrical performance influenced by deformation because of elevation changes,obtains meaningful data and tables of relationship between elevation and parameters of electrical performance in nine bands of 25m antenna.It finds out that when working in high-frequency band, efficiency and gain loss of antenna will be more affected by elevation angle changes.Finally creates conditions for optimizing antenna parameters and performing high reliability tasks such as deep space exploration and aerospace communication.

Abstract: Axial fans are the largest group of blowers and thus have a significant impact on their environment: Their demand for electrical power and the generation of a significant noise emission, have a negative impact on the environment.In this work the improvement of efficiency and reduction of noise emission are subject of the investigations. Several types of low-pressure axial fans are subject of this investigation. Measurements of pressure rise, efficiency and acoustic behavior will be presented for different blade geometries. The modifications of forward- and backward-skewed blades are compared to a unskewed blade geometry. The forward-skewed configurations show an improvement on the hydraulic properties, the efficiency and reduce the noise emission whilst the backward-skewed configurations improve the acoustic behavior at low flow rates with flow detachment occurring. Besides an acoustic quantification of the noise emission using the sound power level, psychoacoustic methods like loudness and sharpness were used.

Abstract: Commonly used turbo machines like axial fans or side channels blowers have a large impact on their environment: Large demand for electrical power and production of strong aeroacoustic sound sources, generating a significant noise emission, lead to a environmental footprint. The current work addresses both tasks: improvement of efficiency and reduction of noise emission. In this work a side channel blower is in the focus of the investigations. Since the noise emission of side channel blowers mainly occurs in the region of the stripper, pressure measurements on the blade surface are performed. The pressure trend during the blade passage along the stripper provides information on the exact location of and the contribution to the acoustic noise generation. Modifications of the stripper geometry with the objective of pressure drop linearization along the stripper are evaluated with respect to efficiency, pressure rise and noise reduction. All acoustic measurements are also evaluated with psychoacoustic quantities, like loudness and sharpness, to account for the human perception.