Aim: The purpose of this study was to investigate whether psychoacoustic parameters could be significantly influenced by the human ear canal and whether gender played a significant role in these effects. Methods: In this study, sixty participants were enrolled, with an equal distribution of 30 male and 30 female individuals. White and sinusoidal noises at 75, 85, and 95 dB as stimulus sound pressure levels (SSPLs). Psychoacoustic parameters such as loudness, sharpness, roughness, and fluctuation strength were measured both outside (cavum part of the external ear) and inside the right ear of each participant. These measurements were done using a circular-shaped microphone with a 2-mm diameter and Labview software. The duration for each measurement was 10 s. The independent sample t-test and repeated measures ANOVA test were employed for the statistical analysis in this study. The results indicated that the equality of means was rejected at a significance level of P < 0. 05. All statistical analyses were conducted using SPSS Version 26. Results: The mean age and standard deviation of all participants were 22. 77 ± 2. 60 years old. The comparison of psychoacoustic parameters in the exposure to different types of noises at various levels between genders showed no statistically significant differences (all P > 0. 05). For both sinusoidal noise and white noise at all three studied SSPLs, the differences in four psychoacoustic parameters between the outer and inner ears of the participants were not statistically significant (all P > 0. 05). Conclusion: Based on our findings, it seems that the human ear canal does not have any effect on psychoacoustic parameters, leading us to conclude that the ear canal does not contribute to noise-induced annoyance.

In present paper, effect of electron scattering due to presence of rough interfaces is investigated on electrical conductance in tunneling structures. The tunneling structure is a fifth layer (double barriers) that all of them are semiconductor. Calculations are carried out in the frame work of nearly free electron approximation and transfer matrix method. Our results show that increasing of roughness results in increasing of incident electrons scattering and also cause to decreasing of transmission probability of electrons, and hence, decreasing of electrical transport through tunneling structures. Besides, with increasing of rough exponent, roughness of surface becomes smoother and into greater rough exponent, interfacial seems more plain. The influence of variation of more than one characteristic of roughness on tunneling current leads to interesting results that can regard in electronic devices fabrication.

The proper operation and quality of the finished product are highly dependent on the surface roughness of parts in a variety of industries. Among the most sophisticated techniques for reducing a part's surface roughness is the magnetorheological polishing procedure. This technique uses a magnetic field and rheological materials to improve the surface roughness of items. The parameters of turning radius, gap, machining time, magnetic pole rotation speed, and workpiece rotation speed have all been studied in the present research. By applying the Sobol method for statistical sensitivity analysis, the parameters have been examined via the surface roughness regression equation. According to the results, the most effective parameters are the workpiece's rotation speed (impact of 51%) and the magnetic pole's rotation speed (impact of approximately 21%). The next parameters to be considered are the machining gap (14% impact) and machining time (11% impact). With a 3% impact, the radius of gyration is thought to be the least important parameter in this process. This means that the time parameter's impact on this procedure can be neglected.

In the last years hexapod machine tool with six degrees of freedom has got the attention of experts for achieving high dexterity and high speed machining. Free form surfaces are widely used in today industries. These surfaces are much encountered in aerospace, auto and other industries. Therefore machining of these surfaces is very important. For interpolation of free form surfaces, NUR5S curves are commonly used. For investigating the quality of machined surface, final surface roughness is very important and is the most important feature of machined surface. In this study the effect of machining parameters such as cutting depth, feed rate and cutting speed on surface roughness were investigated. Design of experiments was done using Taguchi method. Then with using of neural network and genetic algorithm the best case for surface roughness was achieved. The cutting tool used in this study was ball end-mill and the work piece was aluminum of three thousand series. The results showed that cutting speed and depth of cut had the most effect on the surface roughness.

Today, Carbon fiber-reinforced polymer composites (CFRP) have extensive use in different fields such as aerospace, automotive, oil, gas, and defense industries compared to metals, due to the high ratio of strength to weight. Machining of these materials regard to their non-homogeneity structure is complicated. Due to the different thermal expansion coefficients between the fibers and resin polymer composite milling materials difficult to create one of the final parts. Achieve optimal machining conditions, with high efficiency, which need proper analysis and careful investigation. Minimizing the machining time became important Due to developments in CNC technology. One of the time minimizing methods is high-speed machining technology. In this study, composite plates made of carbon/epoxy to a thickness of 10 millimeters, which are often used in the body of Aerospace structures and missiles, have been manufactured by hand layup. The cutting parameters used during the milling operation of the CFRP panel ranged from 1000 rpm to 7000 rpm for the spindle speed, feed rate from 1000 mm/min to 3000 mm/min, and lastly 1.0 mm to 3.0 mm range for depth of cut. the combination of spindle speed, feed rate, and depth of cut are studied at five different levels. 20 runs of experiments are performed based on Response Surface Methodology (RSM). the milling process with two-flute tungsten carbide - coated diamond insert with a 20 mm diameter was performed. their surface quality after milling process is measured. So after roughness, material removal rate and required analysis were performed. Spindle speed has a greatest effect on surface roughness. In conclusion, the influence of the cutting parameters is higher spindle speed, lower feed rate, and lower depth of cut resulting in low surface roughness. The optimized cutting parameters were spindle speed, feed rate, and depth of cut of 7000 rpm, 1000 mm/min and 1 mm respectively with the surface roughness of 1.9 um.

One of the most important factors that affect tire friction is surface roughness, which determines the size of the real contact area, real pressure distribution on the contact interface, and scales of mechanical engagement between viscoelastic rubber and a rough substrate. The need to predict coefficient of friction (COF) for rubber on rough surfaces for applications such as traction of tires on the road surfaces led to some physical models such as Heinrich-Kluppel's model. The current study examines the applicability of the Heinrich-Kluppel model, using different viscoelastic representations, in numerical simulations of COF for rubber, and its agreement with the experimental results. For this purpose, roughness characteristics of the surfaces and viscoelastic properties of rubber were measured by fractal analysis and dynamic-mechanical-thermal analysis (DMTA), respectively. These data were employed in the numerical code to simulate COF for a rubber sample. The model was also modified by replacing the Zener viscoelastic representation in the original model with the generalized Maxwell viscoelastic representation. On the other hand, COF for rubber was measured on the same rough surface (different sand-papers) by an in-house friction tester, and results were compared with the numerical results. It was shown that computer simulation could predict the load and speed dependence of rubber friction very well. The application of the generalized Maxwell model improved agreement between the numerical and experimental results for high sliding speeds where the Zener viscoelastic model failed to predict the right trend in variation of COF with speed. This speed range was matched with the sliding velocities in the footprint of tire under rolling conditions.

This paper is based on the concept of physical mesomechanics, which allows any plastic shear in the stressed body to be considered as a loss of shear stability of the material in local stress concentration zones. This approach, which is physically very well-grounded, allowed us to consider from one standpoint the processes of machining by cutting and wear of steels. Physical and mechanical regularities in the effect of certain processing operations on the shape and roughness of the hydraulic cylinder surface are found. The mechanisms of the spatial self-organization of the relief and surface of bearings under conditions of false brinelling are summarized and analyzed. The data obtained can be used for further scientific generalization or prediction and diagnostics of the surface condition of load-carrying and support elements of mechanical systems under study.

Surface irrigation is still main irrigation system in agricultural land, so it is necessary to finding a solution for improving these systems. Manning roughness coefficient and infiltration parameters are the most important parameters in evaluation of surface irrigation systems. Infiltration parameters play an essential role in the evaluation and design of irrigation systems; therefore, it is necessary to estimate these coefficients, accurately The purpose of this study was to estimate infiltration parameters and manning roughness coefficient in continuous and cutback flows during the first three irrigation events using INFILT, SIPAR_ID and EVALUE models. The results showed that the average relative error percentage in the INFILT, SIPAR_ID and EVALUE models were 16. 6, 5. 2 and 11. 2, respectively, and the maximum errors were 1. 6, 0. 7, and 1. 1 m3, respectively. The SIPAR_ID model has less error than the other two models. These models also had higher accuracy in estimating infiltration in the border irrigation than furrow irrigation. The US Soil Conservation Service (SCS) also proposed a Manning roughness coefficient for fallow furrows in the first irrigation 0. 04, which is very different from the estimated values of the SIPAR_ID model from 0. 038 to 0. 09.

Micro milling is widely used for producing industrial micro parts. In micromachining, approaching the depth of cut to tool cutting tip radius causes some problems in achieving desired surface quality and burr formation. It is impossible to use conventional deburring methods in micro parts due to the reduction of machining scale and the importance of high dimensional accuracy and surface quality. Therefore, it is important to comprehend micro end milling and the effect of process parameters on reducing these problems. In this study, the effect of spindle speed, feed rate and depth of cut on surface roughness and burr size during micro end milling of AISI1045 steel have been investigated using the response surface method. Two flute endmills with 0. 8 mm diameters have been used in this study. Results show that feed rate with 55. 26, 37. 53 and 44. 55 percent contribution on burr size in up milling side, down milling side and surface roughness is the most effective parameter in the micro end milling process. Selecting the maximum amount of spindle speed, feed rate, and the minimum amount of depth of cut causes minimum burr size in both up milling and down milling side. 36000RPM spindle speed, 5. 7mm/s feed rate and 0. 086 mm depth of cut causes the best surface quality in micro-milling of mentioned steel.

The aim of this study was to investigate the factors affecting surface quality of paulownia wood during milling by advanced computer numerical control (CNC) machine. For this aim wood logs converted to proper sizes (2.5x10x15 cm) and then air dried. The variable of this study were spindle speed of machine (10000 and 18000 rpm), feeding rate (6 and 12 m/min), cutting depth (1and 5 mm), cutting method (down and up-milling) and cutting pattern (tangential and radial). Roughness of cut specimens edge were evaluated by profilometer method according to ISO 13565 standard. For evaluation of surface quality Abbott group parameters (Rpk, Rk, Rvk) were used. Degree of effective of the parameters was evaluated by fractional factorial design as completely random design at confidence level of 95%. The result showed that spindle speed, cutting method and feed rate are influencing factors on surface quality of milled specimens and their effect was significant. With increasing spindle speed and decreasing feeding rate the roughness decreased and surface quality improved. In up-milling cutting method, degree of roughness was higher and consequently surface quality was inferior. Cutting method in comparison to other factors had the high influence on surface quality. The rest variable did not have independent influence on surface quality at 95% confidence level.