Wyniki wyszukiwania - BazTech

1

Optimizing the MBBR System and Integrating Nanoparticles to Improve Wastewater Treatment Efficiency

Eid Ahmed, El-Sayed Abd-Elaziz, Ayoub Mohamed, El-Morsy Ahmed

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 2

218--229

EN

Wastewater treatment faces a growing challenge in removing nutrients and organic matter. This study aimed to evaluate the effectiveness of the moving bed biofilm reactor (MBBR) system in removing nutrients and organic from municipal wastewater. The impact of different carrier filling ratios and hydraulic retention times (HRT) on the removal efficiency was systematically investigated. Moreover, the addition of nanoparticle additives to enhance system performance was evaluated. The optimal conditions for the MBBR system were 30–45% filling ratios and a 10-hour HRT, resulting in maximum removal efficiencies for biological oxygen demand (BOD5), chemical oxygen demand (COD) and ammonia (NH4+-N) with a percentage of 85.23%, 81.69%, and 54.45% respectively. Furthermore, adding nanoparticles improved the BOD5 and COD removal efficiencies by 6.6% and 8.0% respectively, compared to the MBBR system without nanoparticles.

2

Modification of Axial Distribution of Fragment Velocity in Preformed Fragmentation Warheads

Li Xin, Wang Weili, Liang Zhengfeng, Dong Jun

Central European Journal of Energetic Materials

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2024

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Vol. 21, no. 1

22--52

EN

Fragment velocity is a crucial parameter for evaluating the destructive capability of a warhead, and it is typically calculated using the Gurney formula with corrections. The currently established correction formulas can determine the axial distribution of natural fragment velocity within the shell, but for a preformed fragmentation warhead, energy losses due to the existence of fragment gaps lead to calculated results that are larger than the actual values, making it unsuitable for accurate calculation of the axial distribution of fragment velocity in such warheads. This paper introduces a filling ratio correction function based on the concept of effective charge and establishes a calculation model for the axial distribution of fragment velocity in preformed fragmentation warheads. The numerical simulation method was validated using prototype ground static explosion test data, then the influence of key parameters such as charge diameter (d), length-diameter ratio (δ), and filling ratio (β) on the axial distribution of fragment velocity was investigated. The relationships between the three parameters (a, m, c) in the filling ratio correction function and the characteristic parameters were derived, and the filling ratio correction function and the calculation formula for the axial distribution of fragment velocity were fitted. Comparisons with existing empirical formulas indicate that the formulas established in this paper offer higher calculation accuracy, with an error of no more than 4.65% compared to measured values, and they can reliably determine the axial distribution of fragment velocity in preformed fragmentation warheads, providing significant practical application value.

3

Thermal analysis of a gravity-assisted heat pipe working with zirconia-acetone nanofluids: An experimental assessment

Abdolhossein Zadeh Amin, Nakhjavani Shima

Archives of Thermodynamics

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2020

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Vol. 41, no 2

65--83

EN

An experimental investigation was performed on the thermal performance and heat transfer characteristics of acetone/zirconia nanofluid in a straight (rod) gravity-assisted heat pipe. The heat pipe was fabricated from copper with a diameter of 15 mm, evaporator-condenser length of 100 mm and adiabatic length of 50 mm. The zirconia-acetone nanofluid was prepared at 0.05–0.15% wt. Influence of heat flux applied to the evaporator, filling ratio, tilt angle and mass concentration of nanofluid on the heat transfer coefficient of heat pipe was investigated. Results showed that the use of nanofluid increases the heat transfer coefficient while decreasing the thermal resistance of the heat pipe. However, for the filling ratio and tilt angle values, the heat transfer coefficient initially increases with an increase in both. However, from a specific value, which was 0.65 for filling ratio and 60–65 deg for tilt angle, the heat transfer coefficient was suppressed. This was attributed to the limitation in the internal space of the heat pipe and also the accumulation of working fluid inside the bottom of the heat pipe due to the large tilt angle. Overall, zirconia-acetone showed a great potential to increase the thermal performance of the heat pipe.

4

Analysis of air flow velocity distribution in the intake system of an SI engine

Kołodziej S., Ligus G., Mamala J., Augustynowicz A.

Combustion Engines

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2017

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R. 56, nr 2

152--157

EN

The conditions of air flow in the intake determine power generated by the engine to a large extent. The biggest resistances in flow of the air sucked or pumped into the engine are generated by the throttle, which is at the same time the main component which allows for regulation of engine power. For the purpose of research conducted in this work, time density of engine work points in analyzed velocity profiles was determined with the use of Engine Road Load Simulator. Thanks to the knowledge of time velocity, it was possible to determine throttle positions at which the engine operates most frequently. With the use of image analysis methods, obtained parameters were experimentally researched, considering flow disturbances which are the effect of air flow through the throttle and uneven air distribution in the intake manifold of a four-cylinder engine.

5

Analiza wpływu średnicy bębna na prędkości charakterystyczne dla wypełnienia stanowiącego ziarno peluszki

Skoczkowska K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2015

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z. 105

197-200

EN

The research include information about impact size of the drum for behaviour of the bed. Research carry out for 5 various degree of the drum filling range from 15 to 35%. Analyzed data of the experimental and estimated results shows difference. The biggest distinction noticed for maximum velocity - 19,8 rpm (for drum with a diameter of 700 mm).

6

Effect of filling ratio on thermal performance and thermal parameters of closed loop pulsating heat pipes

Kolková Z., Malcho M.

Structure and Environment

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2013

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Vol. 5, no. 4

37--40

EN

Improving the performance of electrical components needs higher heat removal from these systems. One of the solutions available is to use a sealed heat pipe with a throbbing filling, where development meets the current requirements for intensification of heat removal and elimination of moving parts cooling systems. Heat pipes operate using phase change working fluid, and it is evaporation and condensation. They have a meandering shape and are characterized by high intensity of heat transfer, high durability and reliability. Advantage of these tubes is that it is not necessary to create the internal capillary structure for transporting liquid and they need no pump to the working fluid circulation. They have a simple structure, low cost, high performance, and they can be used for various structural applications. The choice of working fluid volume and performance affects thermal performance. Distilled water, ethanol and acetone were used in the performance ranges of 0-80%.