Research on Sintering Polytechnic of PTFE/Al Reactive Materials

2013 ◽  
Vol 820 ◽  
pp. 25-29
Author(s):  
Jing Bo Wu ◽  
Mao Quan Li ◽  
Shu Hai Zhang ◽  
Yun Long Mei ◽  
Ze Tao Gao

PTFE/Al reactive material was prepared via a hot pressed sintering process and comparative experiments were conveyed considering heating rate, sintering temperature and heat preservation time. The internal microstructure of the material was investigated using metallurgical microscope and stereomicroscope. From the investigation the influence of process parameters of hot pressed sintering on the properties of the material were deduced, and the analysis was verified by testing the impact initiation property with drop hammer method. The density of the material was measured according to the Archimedean principle. and the results showed that the best operating conditions of these three factors are 80°C/h, 365°C, and 0.5h, This new method has a higher effectively (short process time) and need lower operation conditions (low sintering temperature and pressure) comparing with the traditional cold sintering process.

2014 ◽  
Vol 540 ◽  
pp. 225-228 ◽  
Author(s):  
Long Ma ◽  
Guo Zhong Li ◽  
Ji Rui Hu

The red mud lightweight insulation brick was prepared by the sintering process as red mud, fly ash, bentonite as the main raw material, adding a certain amount of pore forming agent and fluxing agent. The sintering heat preservation time of red mud insulation brick on the properties was studied. The red mud lightweight insulation brick damage fracture microstructure was analyzed using scanning electron microscope (SEM) and the sintering mechanism was discussed preliminarily. The results show that with sintering temperature of 1100°C heating for 180 minutes, the performance of thermal insulation brick is better. When the heat preservation time extends to continue, the performances of sample remain stable basically.


2014 ◽  
Vol 878 ◽  
pp. 264-270 ◽  
Author(s):  
Xiao Huan Wang ◽  
Bao Dong Wang ◽  
Yong Feng Xiao ◽  
Xiao Ting Liu ◽  
Li Jun Zhao ◽  
...  

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six sigma approach was also implemented to analysis the results obtained by the experiments. There is great significance to optimize sintering process for the industrialization of the novel method. Amount of energy consumption will be reduced in the production.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 485
Author(s):  
Abdulkarim Almukdad ◽  
Alaa H. Hawari ◽  
MhdAmmar Hafiz

In this study the removal of Fe and Mn from primary treated municipal wastewater using a new electrode configuration in electrocoagulation was evaluated. The used electrode configuration induced a dielectrophoretic (DEP) force in the electrocoagulation process. The impact of the electrolysis time, electrodes spacing and applied current on the removal of Fe and Mn was evaluated. The maximum removal percentages of Fe and Mn were obtained using an electrolysis time of 60 min, an electrode spacing of 0.5 cm and an applied current of 800 mA. Under these operating conditions and using the new electrodes configuration, the Fe and Mn removals were 96.8% and 66%, respectively. The main advantage of using the DEP-induced electrode configuration was the minimal consumption of the electrodes. The new electrode configuration showed 42% less aluminum content in the reactor compared to the aluminum electrodes with no DEP effect. The energy consumption at the selected operation conditions was 4.88 kWh/m3. The experimental results were comparable with the simulation results achieved by the COMSOL software.


Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1213
Author(s):  
Michael Betz ◽  
Marco Gleiss ◽  
Hermann Nirschl

This paper presents a study of the use of flow baffles inside a centrifugal air classifier. An air classifier belongs to the most widely used classification devices in mills in the mineral industry, which is why there is a great interest in optimizing the process flow and pressure loss. Using Computational Fluid Dynamics (CFD), the flow profile in a classifier without and with flow baffles is systematically compared. In the simulations, turbulence effects are modeled with the realizable k–ε model, and the Multiple Reference Frame approach (MRF) is used to represent the rotation of the classifier wheel. The discrete phase model is used to predict the collection efficiency. The effects on the pressure loss and the classification efficiency of the classifier are considered for two operating conditions. In addition, a comparison with experimental data is performed. Firstly, the simulations and experiments show good agreement. Furthermore, the investigations show that the use of flow baffles is suitable for optimizing the flow behavior in the classifier, especially in reducing the pressure loss and therefore energy costs. Moreover, the flow baffles have an impact on the classification performance. The impact depends on the operation conditions, especially the classifier speed. At low classifier speeds, the classifier without flow baffles separates more efficiently; as the speed increases, the classification performance of the classifier with flow baffles improves.


2021 ◽  
Vol 24 (6) ◽  
pp. 1199-1208
Author(s):  
L. A. Sladkova ◽  
V. V. Krylov ◽  
F. A. Kuznetsov

The purpose of the paper is to reproduce a standard wind flow (laminar, turbulent, pulsating modes) to study the impact on crane structures, with the aim to obtain the load values of crane elements most closely approximate to real conditions. When creating an installation, which is related to the field of experimental aerodynamics, the "principle of simulating the main factors determined by the operating conditions of the research object" is adopted to ensure the r eproducibility of test results to the maximum extent. To confirm the performance efficiency of the proposed installation device, its computer model is developed using the CAD software SolidWorks. The computer model parameters are in full geometric agreement with the dimensions of the developed real installation. The use of the installation makes it possible to study the dynamic effect of the wind on the stability of crane structures in various operation modes (change in wind speed, in the mode of load operation, in operation conditions at the wall, etc.). The proposed installation allows to simulate the loads on crane equipment with the possibility of characteristics expanding, for example, its carrying capacity. The generated computer model of the installation makes it possible to reveal the physical picture of wind flow distribution at the installation outlet. The results of wind flow simulation on the proposed installation are confirmed on a computer model with a high degree of convergence of results at wind speeds of 2.5 m/s and lower The installation proposed by the authors will allow to simulate: the value of the real average statistical wind load of various intensity; pulsating component of the wind load; vortex excitation; increase of the available aerodynamic research capability for a real crane structure. The developed installation is a calibration device for external impacts of the wind force on the crane structure.


2013 ◽  
Vol 85 (2) ◽  
pp. 453-462 ◽  
Author(s):  
Arita Dubnika ◽  
Dagnija Loca ◽  
Aigars Reinis ◽  
Maris Kodols ◽  
Liga Berzina-Cimdina

In the present study, the impact of sintering temperature on the phase composition and antibacterial properties of silver-doped hydroxyapatite (HAp/Ag) samples was investigated. HAp/Ag containing 0.2 and 1.2 % silver was prepared using a modified wet chemical precipitation method. The surface morphology and inner structure of the sintered samples were discussed. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) studies showed that, after the sintering process, HAp/Ag contained a silver oxide phase, which was not observed in raw materials. Phase composition changes at different sintering temperatures were studied, and it was found that silver oxide undergoes phase changes during the sintering process. In vitro antibacterial properties approved the excellent antimicrobial activity of HAp/Ag against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa. The HAp/Ag sample with 1.2 % silver content, sintered at 1150 °C, showed the highest antibacterial activity.


2005 ◽  
Vol 33 (3) ◽  
pp. 156-178 ◽  
Author(s):  
T. J. LaClair ◽  
C. Zarak

Abstract Operating temperature is critical to the endurance life of a tire. Fundamental differences between operations of a tire on a flat surface, as experienced in normal highway use, and on a cylindrical test drum may result in a substantially higher tire temperature in the latter case. Nonetheless, cylindrical road wheels are widely used in the industry for tire endurance testing. This paper discusses the important effects of surface curvature on truck tire endurance testing and highlights the impact that curvature has on tire operating temperature. Temperature measurements made during testing on flat and curved surfaces under a range of load, pressure and speed conditions are presented. New tires and re-treaded tires of the same casing construction were evaluated to determine the effect that the tread rubber and pattern have on operating temperatures on the flat and curved test surfaces. The results of this study are used to suggest conditions on a road wheel that provide highway-equivalent operating conditions for truck tire endurance testing.


2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.


2014 ◽  
pp. 298-301 ◽  
Author(s):  
Arnaud Petit

Bois-Rouge factory, an 8000 t/d cane Reunionese sugarcane mill, has fully equipped its filtration station with vacuum belt press filters since 2010, the first one being installed in 2009. The present study deals with this 3-year experience and discusses operating conditions, electricity consumption, performance and optimisation. The comparison with the more classical rotary drum vacuum filter station of Le Gol sugar mill highlights advantages of vacuum belt press filters: high filtration efficiency, low filter cake mass and sucrose content, low total solids content in filtrate and low power consumption. However, this technology needs a mud conditioning step and requires a large amount of water to improve mud quality, mixing of flocculant and washing of filter belts. The impact on the energy balance of the sugar mill is significant. At Bois-Rouge mill, studies are underway to reduce the water consumption by recycling low d.s. filtrate and by dry cleaning the filter belts.


Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.


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