Concurrent impact of chipping and pitting damages in a locomotive power transmission system

Farshad Niksai,Mohammad Ali Rezvani 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

The reliability of power transmission systems in locomotives directly impacts trains' availability and running safety. The failure of gears, like pitting and chipping on teeth, is a common failure that can affect vehicle dynamics and reduce the system's safety and reliability. Based on the frequent visual inspections, the simultaneous occurrence of pitting and chipping on gear teeth are observed. It is the purpose of this research to investigate these defects and their possible coincidence. The dynamic response of the gear system to the presence of the pitting and chipping damages on one tooth, individually and concurrently, is theoretically and experimentally evaluated and compared. The dynamic interaction between the gear system and other elements, such as the traction motor and wheelset, is based on the operational conditions. The time-variant mesh stiffness is considered the primary internal excitation in the dynamics of the gear system. An analytical method based on the potential energy is used. The defects' coincidence effect on the dynamic response in time and frequency domains is studied. To measure the severity of the defects, some statistical parameters for different failure cases are calculated and compared. As a result, the parameters that exhibit the most sensitivity to the corresponding failure are introduced.

Effect of Cholesterol-loaded-cyclodextrin in Presence and Absence of Egg Yolk during Freezing Step on Quality of Markhoz Buck's Spermatozoa

Farshad, A.,Amidi, F.,Khor, A. Koohi,Rashidi, A. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.2

Cryopreservation protocols induce partially irreversible damage to mammalian sperm plasma membranes. Previous studies have indicated that adding cholesterol to the plasma membrane, as cholesterol-loaded-cyclodextrins, improves cryosurvival of sperm. Therefore, the purpose of this study was to determine if treating sperm of Markhoz bucks with cholesterol-loaded-cyclodextrins (CLC) (0, 0.75, 1.5, 2.25 and 3 mg/ml diluted $240{\times}10^6$ sperm/ml) in Tris-citric acid-glucose diluents with and without egg yolk (containing 5% glycerol) would improve the post-thaw sperm quality. The motion characteristics were evaluated with a Computer Assisted System Analyzer (CASA); acrosome integrity and vitality were measured with the triple-stain technique. Samples were recovered before and after freezing by means of putting straws into $37^{\circ}C$ water for 30 sec and then parameters were assessed. The results showed that the treatments significantly affected motility, progressive motility, recovery rate, curvilinear velocity, beat cross frequency, live sperm with reacted acrosome, live sperm with unreacted acrosome, dead sperm with reacted acrosorne, and dead sperm with unreacted acrosome during freezing (p<0.05). However; no significant differences were found for average path velocity, straight line velocity, amplitude of lateral head displacement, straightness and linearity (p>0.05). The best results were observed for extender containing 2.25 mg/ml ($240{\times}10^6$ sperm/ml) CLC supplemented with 2.6% egg yolk. In conclusion, the findings of this study indicate improved Markhoz sperm viability and motility following treatment in the presence of egg yolk.

Element loss analysis of concentrically braced frames considering structural performance criteria

Farshad Hashemi Rezvani,Behrouz Asgarian 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.3

This research aims to investigate the structural behavior of concentrically braced frames after element loss by performing nonlinear static and dynamic analyses such as Time History Analysis (THA), Pushdown Analysis (PDA), Vertical Incremental Dynamic Analyses (VIDA) and Performance-Based Analysis (PBA). Such analyses are to assess the potential and capacity of this structural system for occurrence of progressive collapse. Besides, by determining the Failure Overload Factors (FOFs) and associated failure modes, it is possible to relate the results of various types of analysis in order to save the analysis time and effort. Analysis results showed that while VIDA and PBA according to FEMA 356 are mostly similar in detecting failure mode and FOFs, the Pushdown Overload Factors (PDOFs) differ from others at most to the rate of 23%. Furthermore, by sensitivity analysis it was observed that among the investigated structures, the eight-story frame had the most FOF. Finally, in this research the trend of FOF and the FOF to critical member capacity ratio for the plane split-X braced frames were introduced as a function of the number of frame stories.

Modeling interfacial tension of (CH4+N2)+H2O and (N2+CO2)+H2O systems using linear gradient theory

Farshad Varaminian,Shahin Khosharay 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3

The linear gradient theory (LGT) of fluid interfaces in combination with the cubic-plus-association equation of state (CPA EOS) is applied to determine the interfacial tensions of (CH4+N2)+H2O and (N2+CO2)+H2O ternary mixtures from 298-373 K and 10-300 bar. First, the pure component influence parameters of CH4, N2, CO2 and H2O are obtained. Then, temperature-dependent expressions of binary interaction coefficient for (CH4+H2O), (N2+H2O)and (CO2+H2O) are correlated. These empirical correlations of pure component influence parameters and binary interaction coefficients are applied for ternary mixtures. For (CH4+N2)+H2O and (N2+CO2)+H2O mixtures, the predictions show good agreement with experimental data (overall AAD~1.31%).

Seismic Behaviour Assessment of Steel Moment Resisting Frames Under Near-Field Earthquakes

Farshad Taiyari,Antonio Formisano,Federico M. Mazzolani 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.5

In this paper, some seismic factors, namely response modifi ers, ductility, overstrength and defl ection amplifi cation, of steel moment resisting frames (MRFs) under near-fi eld records are evaluated. To this purpose, two separate groups of near-fi eld records (e.g., pulse-like and non-pulse-like) on the behaviour of MRFs are studied. In particular, four models with diff erent storey heights (3-, 6-, 9-, and 12-storeys) are examined through IDA analyses under 20 pulse-like and 20 non-pulse-like ground motion records. Finally, the achieved results are compared with the recommendation values of the ASCE code to assess their reliability. According to the results, the MRF structures demonstrate better seismic behaviour under the nonpulse- like ground motions rather than pulse-like ones. The average response modifi cation factor obtained from non-pulse-like ground motions is about 5.0, which is 1.19 times higher than the corresponding results achieved from pulse-like records.

Total domination number of central graphs

Farshad Kazemnejad,Somayeh Moradi 대한수학회 2019 대한수학회보 Vol.56 No.4

Let $G$ be a graph with no isolated vertex. \emph{A total dominating set}, abbreviated TDS of $G$ is a subset $S$ of vertices of $G$ such that every vertex of $G$ is adjacent to a vertex in $S$. \emph{The total domination number} of $G$ is the minimum cardinality of a TDS of $G$. In this paper, we study the total domination number of central graphs. Indeed, we obtain some tight bounds for the total domination number of a central graph $C(G)$ in terms of some invariants of the graph $G$. Also we characterize the total domination number of the central graph of some families of graphs such as path graphs, cycle graphs, wheel graphs, complete graphs and complete multipartite graphs, explicitly. Moreover, some Nordhaus-Gaddum-like relations are presented for the total domination number of central graphs.

Non-Pharmacological Treatments of Psoriasis in Persian Medicine a Narrative Review

Farshad Mohammadian Rasanan,Hoorieh Mohammadi Kenari,Mohammadreza Ghassemi,Ali Jabbari Sabbagh,Jale Aliasl,Ali Ghobadi 대한약침학회 2022 Journal of pharmacopuncture Vol.25 No.1

Psoriasis is a chronic disease that has no definitive cure. In this review study, the main sources of Persian Medicine (PM) such as the Canon of Medicine (by Avicenna) and AlHavi (by Rhazes) were assessed to identify non-pharmacological treatments for psoriasis. Several treatments that are recommended for this disease include nutritional advice, lifestyle modifications, and manipulation therapy such as wet cupping (Hijamah), leech therapy, and phlebotomy (Fasd). These recommendations may help to prevent recurrence and be useful in improving psoriasis. The efficacy of PM recommendations to improve psoriasis should be evaluated in future studies.

Letters to Editor : Mirror Therapy as an Alternative Treatment for Phantom Limb Pain: A Short Literature Review

( Farshad Hasanzadeh Kiabi ),( Mohammad Reza Habibi ),( Aria Soleimani ),( Amir Emami Zeydi ) 대한통증학회 2013 The Korean Journal of Pain Vol.26 No.3

Seasonal Changes in Serum Testosterone, LDH Concentration and Semen Characteristics in Markhoz Goats

Farshad, A.,Yousefi, A.,Moghaddam, A.,Khalili, B. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.2

This experiment was conducted to study variations of serum testosterone and seminal characteristics of Markhoz male goats. Blood samples were obtained via jugular vein, and semen was collected by using an artificial vagina from 14 fertile male goats (2-3 years of age), at 15-day intervals starting on 15 July and ending on 30 October 2010 (during breeding and non-breeding season). Semen volume, total sperm (volume${\times}$concentration), live sperm (%), abnormal sperm (%) and semen pH were significantly superior during the late summer and early autumn (breeding season). Variation of sperm density, motility and progressive motility was not significant during the sampling period. The results presented show that the lowest and highest levels of lactate dehydrogenase in the seminal plasma were recorded in late October (2.82 U/ml) and in late August (4.81 U/ml), respectively. Moreover, the study indicated that the serum testosterone concentration was higher during late summer and early autumn (p<0.05) than at any other of sampling period. There were negative correlations between volume and sperm density (-0.135, p<0.05), and positive correlations between volume and percentage live sperm (0.224) and percentage progressive motility (0.194, p<0.01). Sperm density was correlated with live sperm (0.200, p<0.05) and progressive motility (0.202, p<0.01). The correlation between live sperm and progressive motility was 0.554 (p<0.01). Furthermore, the results in this study indicated a significant positive correlation between live sperm and LDH (0.450) and a negative correlation between sperm density and LDH concentration (-0.272) (p<0.01). Significant, but positive correlations were found between sperm motility and LDH (0.542) and testosterone concentration (0.522), respectively (p<0.05). In conclusion, this study demonstrated that the best obtained semen was collected in late summer (during decreasing photoperiod) and early autumn (September and October). This also coincides with the natural breeding season of Markhoz goats in Iran.

Recent advances in generalized thermoelasticity theory and the modified models: a review

Farshad Shakeriaski,Maryam Ghodrat,Juan Escobedo-Diaz,Masud Behnia 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.1

A review of the recent studies on the generalized thermoelasticity theories and their associated modified models is presented. The aim is to outline an overview of the utilization and physical limitations of available relevant theories. By contrast to classical thermoelasticity theory, generalized thermoelasticity theories (second sound) can involve a hyperbolic-form transport correlation and are motivated by experiments illustrating more accurately of the wave-form heat transfer (second sound). Many researchers have formulated such theories on different fields and analyzed various problems, presenting characteristic properties of these theories. This paper expresses a self-included bibliographical review of previous documents in the area of the second sound. The general structure of this review contains theories, formulations, real limitations, and used solution techniques of the equations for different geometries and loadings. Given that the classical theory is feeble in simulating the temperature distribution, especially in the structures under a sudden thermal shock, this review may be a useful tool for researchers who work in sensitive industries such as steam turbines, micro-temperature sensors, and lithium battery manufacturing.