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Recently, flexible and environmental-friendly aerogel blankets have attracted considerable attention. In this work, the novel silica aerogel/basalt blanket was prepared using basalt fibers via a two-step sol-gel process followed by an ambient drying method and immersing the basalt fiber layer into silica sol. The silica aerogel particles were characterized by FTIR, FE-SEM and nitrogen adsorption analysis. The morphology, hydrophobic properties and surface roughness of neat basalt fiber and its aerogel blanket were also investigated. The density if 0.34 g/cm³, the porosity of 85%, mean pore size of 7±1.5 nm and the surface area of 750 m²/g for the nanostructured silica aerogel particles are obtained. The formation of nanostructured silica aerogel particles on the surface of basalt fibers in the sol-gel process were efficiently occurred leading to a strong hydrophobicity the blanket samples (contact angle of 114°) compared to the hydrophilic neat basalt fibers. The surface roughness of basalt fiber in the blanket samples was increased due to the fiber surface coating with silica aerogel particles. Increasing the sol volume in the synthesis process increased the basalt surface roughness from 3.6μ to 11μ. 

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One of the problems for use of rubber in various industries is the surface tension at the surface of rubbers, which results in the crack on the surface, fracture of the rubber and reduces its service life. These tensions are caused by contacting the rubber component with the metal surface and the friction between two surfaces. Roughness of the surface, the composition of the rubber compound, the environmental factors, test conditions and etc. affect the friction between rubbers – metal. Surface roughness plays an important role in sliding between two surfaces and mainly controls friction behavior. On the other hand, roughness effect on the coefficient of friction is controllable using a suitable lubricant. In the present study regarding to the application of JP4 as an aviation fuel, the effect of JP4 fuel as a lubricant was investigated in the reduction of the sliding friction coefficient between the NBR and aluminum surfaces with different roughness. Experimental studies showed, friction coefficient has a good correlation with the mean surface roughness (Ra). By applying JP4 lubricant, the coefficient of friction decreased by about 75%. JP4 fuel as lubricant has changed the trend of varying friction coefficient from decreasing to increasing regard to the surface roughness.

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Research subjec: Polyethylene surfaces are often modified because of different reasons such as cleaning, etching, change in the performance of the surface, and surficial precipitation. One of the surfaces in the blow molded applications that must be treated in order to be ready for the adhesion of the labels is the surface of the bottle of the hygiene detergents, being the purpose of this research. In this paper, gliding arc plasma device is used at atmospheric pressure with air gas to modify the surface of polyethylene sheets in order to change their structure.
Methods: Various analyzes such as AFM, SEM and XPS tests have been used to investigate the changes in the chemistry and physics of polyethylene surface after plasma modification. Optical emission spectroscopy (OES) has also been used to identify plasma elements.
Findings: The contact angle between the water droplet and the polyethylene surface reached 46.96 ° after 40 s of treatment, while this contact angle was 66.53 °‌ before plasma treatment. The decrease in the contact angle size of the water droplet and the sample surface indicates the hydrophilicity of the polyethylene surface after plasma modification. The surface free energy of polyethylene was calculated before and after plasma modification using the Owens-Wendt-Rabel Kaelble method. The surface energy of polyethylene has increased from 42.20 mj.m^-2 in the control sample to 60.32 mj.m^-2 in the modified sample. The increase in surface roughness of the modified sample with gliding arc plasma was confirmed by AFM test. The surface roughness of polyethylene in the control sample was 47.18 nm, while the roughness in the modified sample increased to 59.86 nm. The XPS test confirmed the presence of oxygenated and nitrogenous functional groups on the surface of the modified sample. This test also showed the formation of C−C=O and C−O−C bonds on PE surface.
 

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γ–TiAl intermetallic has outstanding properties such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration and high working temperature. These intermetallics are applied in aerospace and automotive industry, turbojet engines and blade manufacturing. In this paper, powder mixed electrical discharge machining (PMEDM) of γ–TiAl intermetallic by means of different kinds of powders including Al, SiC, Gr, Cr and Fe is investigated to compare the output characteristics of the process such as surface roughness, tool wear rate, material removal rate and surface topography with each other. This is an experimental investigation, by means of die sinking EDM machine and a special tank for machining. The results indicate that, aluminum powder as the most appropriate kind of powder in the optimum particle concentration of 2 g/l, improves the surface roughness about 32% comparing with conventional EDM, decreases the tool wear rate about 19%, but decreases the material removal rate about 7.5% and also the Al powder leads to improving the machined surface topography and decreasing the surface defects and micro cracks.

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Thin walled structures are among the main parts for several industrial machines. They usually expose variant stresses; therefore fatigue is their major failure mechanism. However experimental observations of the cross section of failed parts indicate that their fatigue fracture differs from what generally expected as high-cycle fatigue behavior. The mathematical estimations demonstrate that stress concentration due to surface roughness plays greater role compare to other surface metallurgical factors which may be predominant factor in the case of fatigue crack generation for thick walled structures. Generating several experimental data, an attempt is made in this study, to investigate fatigue failure of these particular parts. In addition the practical equation available in machine component design books is modified to implement the effect of manufacturing parameters properly. Application of developed equation makes it possible for designers to communicate with manufactures in a better way by proposing expected surface quality. The manufacturers are supposed to choose suitable fabricating parameters (particularly machining parameters) to achieve required quality. In addition this criterion may be inspected easily by quality control managers even via visual inspection.

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In this research the Magnetic Abrasive Finishing capabilities in AISI 4140 steel polishing was studied. Surface roughness was considered as a function of the tool rotational speed, working gap, abrasive material and abrasives particle mesh size. To conduct the tests, a specific magnetic tool was designed to polish the flat steel surfaces by a milling machine. Experiments were arranged based on Taguchi method and using abrasive material consisting of Aluminum Oxide or Silicon Carbide with paraffin oil and Carbonyl Iron powders with different mesh sizes. After surface roughness measurement of samples, the effect of each parameter on the surface quality was inspected by ANOVA method. Results showed that in Magnetic Abrasive Finishing of mentioned steel, the parameters of working gap, tool rotational speed and the abrasive material type are of the most importance as ordered. Finally, a roughness predictor function was introduced by regression method.

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The near dry EDM process uses a mixture of a liquid and a gas as dielectric medium. In this study, near dry EDM process at three levels of discharge energy and with two brass and copper electrode was studied to investigate the effects of tool material on machining performance. Also, the Taguchi method of design of experiments technique was employed to study the effects of nonelectrical parameters such as tool rotational speed, liquid flow rate, gas pressure and also discharge energy on material removal rate (MRR), electrode wear ratio (TWR) and surface roughness (SR) and also the analysis of variance (ANOVA) was employed to find the most important factors effecting MRR, TWR and SR. The results showed that copper electrode has higher MRR and lower TWR as compared to brass electrode. Also the analysis of main effect plots obtained by Taguchi method indicated that MRR and SR is enhanced by increasing water flow rate and discharge energy and also increasing gas pressure leads to lower TWR. The ANOVA results showed that discharge energy is the most important factor influencing MRR, TWR and SR.

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Using of minimum quantity of lubricant in near dry machining is one the new method in machining processes that causes improvement of process. In this study, the role of near dry lubrication is investigated on tool wear in turning of Monel K500. The used tools are consisted of simple and viper ceramic tools. After preparation of process on lathe machine, the designed experiments are done. During the experiments force, surface roughness and tool wear are measured. The obtained results confirm that near dry lubrication causes the reduction of tool wear considerably. Also, viper ceramic tool has less tool wear rather than simple ceramic tool.

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In this paper an innovative vibration rotary tool was designed and manufactured. Vibration turning tool is a compound of turning rotary tool and ultrasonic assistant turning. In this tool, an ultrasonic wave generator with power equal to 20 KHz transducer that has a rotational motion during the process was used. For tool vibration, a stainless horn with resonance frequency equal to 20618 Hz, were designed and manufactured. Round insert with 10 millimeter diameter were used. One of the most important key points in this setup is that the simultaneous rotation and vibration has to be achieved. For rotational motion a motor power and a rack and pinion were used. Also a structure with ability to mount on turning machine were designed and manufactured. Cutting force and surface roughness for each experiment were measured and compared with data collected from conventional rotary tool on 7075 aluminum material. Results shows that ultrasonic vibration cause decreasing in cutting tools and surface roughness, tremendously.

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This paper studies the effects of soluble cutting fluid-based CuO Nanofluid on machining force and surface roughness in turning of hardened AISI 4340 tool steel. These influences, Moreover, are compared with the outputs of similar tests through dry and soluble cutting fluid. The obtained results showed 1% volume fraction of CuO Nanoparticles added to soluble oil as cutting fluid was considerably reduced machining force and surface roughness in comparison to soluble cutting oil and dry. The investigations indicated that CuO Nanofluid reduced surface roughness and machining force by 49% and 24% respectively. Moreover, the results illustrated that the lowest surface roughness obtained in cutting speed 250 m/min, feed rate 0.1 mm/rev and cutting nanofluid.

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Gears are one of the most important elements of any power transmission system. Among all types of gears, helical gears are more common due to their high capacity in power transmission as well as lower level of noise. The aim of this study is to present a model for analyzing the contact of teeth of helical gears considering thermal effects and surface roughness. In the present model, each helical gear is divided to several narrow spur gears in which each of the spur gears have a small rotation angle relative to the previous one. Also each contact point of gears is replaced with contact of two equivalent cylinders. Considering the fact that the governing regime for gears lubrication is the mixed-elastohydrodynamic regime, the total load is carried by lubricant and asperities' contact. Meshing and lubrication analysis of a pair of helical gears is conducted based on the load-sharing concept and parameters such as film thickness, friction coefficient and temperature rise are predicted. The predictions based on the load-sharing concept are compared to other published results Acceptable accuracy, short execution time along with considering thermal and roughness effects are some of the major characteristics of this study.

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In this paper, in order to avoid the problems induced by cutting liquids like higher cost, environmental pollution and dangerous for operator health in milling process and also using the benefits of them such as increasing tool life and machined surface quality, machining by minimum quantity of lubrication (MQL) or near dry lubrication was introduced and that’s effects on main outputs (consumed power and surface roughness) was compared with other lubrication methods such as lubrication by cutting fluids and by air. In order to perform a series of experiments and investigate the effects of different process parameters such as tools rotational speed, feed rate, gas pressure and liquid flow rate on main outputs, the Taguchi method of design of experiments was employed and then the analysis of variance (ANOVA) was used to find the most important factors effecting main outputs. The results obtained by experiments showed that employing near dry lubrication leads to lower electrical power and comparable surface roughness as compared with other lubrication methods. The analysis of variance showed that feed rate is the most important factor affecting consumed power and liquid flow rate is the most important factor influencing surface roughness.

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AISI 4340 steel is a low alloy steel with high tensile strength that has numerous applications in industry. Machinability of this alloy steel has difficulties due to its low heat conduction and high heat concentration in cutting zone. Therefore, use of cutting fluids in machining of this steel is inevitable. On the other hand, environmental problems of using mineral lubricants lead industries into use of biodegradable oils such as Vegetable based cutting fluids. The aim of this study is to investigate the drilling of AISI4340 alloy steel in presence of semi-dry lubricant and using soybean vegetable-based oil. For this purpose, drilling parameters including feed rate and cutting speed at three levels and workpiece hardness at two levels were chosen. Totally 18 experiments were carried out using coated carbide drill. Results revealed that vegetable-based oil can effectively be used in drilling using a semi-dry lubrication method. In addition, feed rate was the most effective parameter on cutting force and surface roughness and by increasing it, the cutting force increased, and the surface quality deteriorated. Also, workpiece hardness showed significant effect on surface roughness.

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AISI4340 hardened steel have a vast functionality in industries. Hard machining of this steel have several benefits such as, higher productivity, lower production cost and improved workpiece properties. In machining operation, ultimate surface roughness is the most important characteristic of machined surface and plays an important role in workpiece life. One of the effective factors on surface integrity is cutting fluid used in machining operation, which have health and environmental problems is spite of positive effects. As a result, using minimum quantity lubrication is considered as an alternative method. In present study, relations between milling parameters and final surface quality in milling of AISI4340 hardened steel, in the presence of lubrication systems including; dry, wet and minimum quantity lubrication have been investigated. Cutting speed, feed rate, axial and radial depth of cut have been considered as main parameters of milling operation. Totally, 90 experiments have been done using response surface method to analyze the effects of process parameters on surface roughness. Results revealed that feed rate and cutting speed have the most Influences on surface roughness. Also higher values of cutting speed and lower values of feed rate are necessary to reduce surface roughness. In addition, compared to other lubrication methods, minimum quantity lubrication have the best performance in surface quality, especially in high cutting speed and depth of cut.

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Lubrication is an essential factor in sheet metal forming processes such as deep drawing in order to reduce friction at contact surfaces, forming load, tool wear rate and increasing of sheet formability. Various metal oxide nanoparticles can be used as additives to create desirable tribological properties in base lubricants because of their unique properties such as specific surface area. In the present study, the conventional lubricant enhanced by alumina nanoparticles (Al2O3) is utilized in deep drawing process in order to improve frictional conditions. The forming load, surface roughness (Ra) and thickness distribution values of the formed cups were assessed to evaluate the performance of the enhanced conventional lubricant with alumina nanoparticles (Al2O3) in comparison to the conventional lubricant and dry forming condition. The obtained results from experimental tests revealed that adding 0.5 wt.% Al2O3 nanoparticles to the conventional lubricant improves lubrication property significantly and reduces forming load by 16.39% and surface roughness by 19.33% compared to the conventional lubricant. Furthermore, it is observed that using lubricant containing nanoparticle additives results in 23.94% improvement in maximum thickness reduction in critical zone.

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Micromilling is a machining process in manufacturing of the miniature parts. Because of high oxidation and corrosion resistance, high fatigue strength and application of Ti6Al4V in hi-tech industries, in this paper surface roughness and burr formation in micromilling of this alloy have been investigated. Cutting parameters including spindle speed, feed rate and axial depth of cuthave been considered as input parameters of tests. Experiments have been performed for two cases: a) in presence of the minimum quantity lubrication and b) wet conditions. Carbide micro-end mill tool of diameter 0.5 mm and TiAlN coating was used. The Taguchi experimental design method has been used to design and analysis of results. Results showed that the spindle speed and feed rate were the most effective parameters on the surface roughness and burr width of titanium alloy, respectively. Also, by increasing both of these parameters, surface roughness and burr width were decreased. In addition, application of minimum quantity lubrication technique significantly improved the surface quality, and it was more effective in upper levels of spindle speed and axial depth of cut. Finally, the best surface quality was attained in spindle speed of 30000 rpm, feed rate of 0.8 μm/tooth and cutting depth of 60 μm.

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Stereolithography has the most portions through rapid prototyping techniques in injection molding and vacuum casting manufacturing because of simultaneously possessing of dimensional accuracy and strength. However low surface finish and appearance of stair-step phenomenon, restrict extension of use of this process. In this research, the influence of process parameters and part orientation on surface finish was studied. For this purpose parts were built in various conditions of surface angle, hatch space and post curing time. Surface roughness measured by contact and non-contact method. Surface angle was in 0-180 degree range by 2 degree step. Considered post curing time was 20, 50 and 80 minute and hatch spacing was 50, 75, 100 and 125 micrometer. In non-contact method using digital microscope, surface profile obtained and then surface roughness calculated using MATLAB software. Finally using Analysis of Variance (ANOVA) a mathematical model has been developed among parameters and responses. Results showed that surface finish has reverse relation with hatch space and are almost Independent of post curing time. Surface roughness in up-facing increases with surface angle enhancement swiftly and then it drops. In down-facing Surface roughness increases with surface angle enhancement slowly and then it falls. Comparison of real dates with estimated values showed that estimation average error is less than 14 percent.

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In this research the abrasive flow finishing process (AFF) of AISI H13 hot work steel was studied and the effects of various process parameters such as flow pressure (extrusion pressure), abrasive particles densities, abrasive particles sizes and the first quality of surfaces on variations of surface roughness and material removal have been investigated. The results showed that increasing the density of abrasive particles leads to increase in variations of surface roughness and material removal. Increase of extrusion pressure from 4 to 6 MPa causes the increase in variations of surface roughness and material removal and from 6 to 8 Mpa leads to decrease in the two latter. Electron microscopic results showed that increase of finishing process time over 4 hours causes a detrimental effect on the surface of the specimens, as a result of penetration and stabilization of abrasive particles in the form of broken particles. Also according the results of this paper, increasing the size of abrasive particles leads to higher variations of surface roughness and material removal, and this process is more effective in finishing of rougher surfaces.

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The subcooled flow boiling occurs when the bulk temperature is less than saturation temperature of the liquid at that pressure while the surface temperature is higher. The most importance of boiling phenomenon is related to the high latent heat of fluid which could removes high heat flux at relatively low temperature difference between liquid and the hot surface. In this study, the impact of velocity and roughness on the subcooled flow boiling were investigated experimentally for pure water. An experimental setup was designed and manufactured. The experimental setup consists of a plexiglass channel with cross section 20×30 mm and the length of 120 cm. A cylindrical heater with diameter 12 mm made of copper is located on the bottom surface of the plexiglass channel. All the experiments were conducted for the surface roughness of 0.65, 2.5 and 4.4 µm at velocities of 0.5, 0.7 and 0.9 m/s. The experimental results show that the surface heat flux increases as the surface roughness and velocity increases. However, this affect of velocity enhancement was only observed for lower boiling surface temperature and opposite trend has taken place for higher boiling surface temperature. This is due to the simultaneous consideration of the convection and boiling terms along with the interaction between them which has not been presented experimentally yet. It appears that this kind of experimental study has not been carried out for copper type surfaces.

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Inducing compressive residual stress is one of the methods of improving fatigue life in metallic components. There are numerous and various methods for inducing compressive residual stress, such as shot peening and deep rolling. One of the most recent and most advanced methods for inducing compressive residual stress in industrial components is Laser Shock Peening (LSP). LSP is a relatively new and complex process, therefore, vast experimental investigations are needed for better understanding the process. For this purpose in the present work, an Nd: YAG Laser with 1200mJ of energy per pulse was used to investigate the LSP process experimentally on Al 6061- T6 alloy. The effect of process on the hardness beneath the surface, the microstructure, and the surface roughness was studied. In addition, in order to investigate the effect of the LSP process on a notch, a notched sample was treated using the LSP process. The results showed that the process could increase the hardness of the material up to 1000μm below the surface. Furthermore, the results showed that the surface roughness would slightly get increased, while this increase could be limited by properly selecting the process parameters. The LSP process of the notched sample showed that this process could lead to the growth of cracks in such samples.