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Functional and Environmental Advantage of Cleaning Ti5B1 Master Alloy
Aleksandar Mitrašinović,Miloš Tomić 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.3
One of the greatest environmental goals for the aluminum alloys industry is generating higher quality products by introducing cleaner input materials while maintaining low production costs. A typical dilemma for the master alloy producers is the cleanness level of the master alloy since insoluble inclusions could serve as inoculants during the solidification process. In this work, commercial Ti5B1 master alloy is used for grain refinement of Al7Si4Cu aluminum alloy and compared with the cleaned master alloy that contained a lower amount of residual refractory oxides and salts. Metallography analysis was used for grain size measurement while Computer Aided Cooling Curve Analysis was used for assessment of the undercooling and heat release values. In all instances, specimens treated with the cleaned master alloy showed smaller grains in the final structure and lower undercooling values. The difference in released heat between liquidus and recalescence temperatures was about 25% in specimens where added 0.66 wt% of cleaned master alloys compared to specimens where the commercial master alloys were added. Using cleaner Ti5B1 master alloy with a higher number of TiAl 3 and TiB 2 particles improves its grain refi nementefficiency and transmits fewer impurities in produced parts. Producing cleaner master alloy would be beneficial from economic and environmental aspects by increasing its value and service time of produced parts besides simplifying the recycling process at the end of parts life-cycle.
Mitra Beigi,Ensiyeh Karimi,Rasoul Abedi,Nooshin Kejani,Siamak Khorramymehr 국제무예학회 2024 International Journal of Martial Arts Vol.9 No.-
Biomechanical assessment of Taekwondo athletes’ motion is essential to improve their performance. It is well known that balance tasks such as Hakdariseogi are determinant techniques which affect the result of a competition. So the aim of this study is to compare biomechanical variables of the support leg during Hakdariseogi task between elite and non-elite taekwondo athletes. Eighteen taekwondo athletes including ten elite and eight non-elite were participated. Six high-speed motion cameras and one force plate were used to acquire kinematics and kinetics data. MATLAB R2017b was used to plot support leg’s joints curves. Statistical analysis was performed to compare variables between two mentioned groups.The average of joints’ angles in the elite group was significantly more than non-elite group during the movement and balance phases (p<0.05).The amount of knee angular velocity in elite athletes was meaningfully higher than non-elite athletes during the movement phase (p<0.05). Also, the average amount of hip and ankle moments was greater in elite athletes during balance phase (p<0.05).There were no meaningful differences in other moment variables between elite and non-elite athletes (p>0.05).In some conditions, elites had more stability with greater angles and moments in the support leg’s joints. So they could perform Hakdariseogi task more quickly or in higher range of values than non-elite group and also generate more muscle activity due to the greater net joint moments, to create more joint moments for better control and stability, and neutralizing the external moments (such as ground reaction moments).
Improved DCT-Based Image Coding and Decoding Methods For Low-Bit Rate Applications
Mitra, Sanjit K.,Jung,sung-Hwan 國立昌原大學校 基礎科學硏究所 1994 基礎科學硏究所論文集 Vol.6 No.-
The discrete cosine transform(DCT) is well known for highly efficient coding performance, and it is widely used in many image compression applications. However, in low-bit rate coding, it produces undesirable block artifacts that are visually not pleasing. In addition, in many applications, faster computation and easier VLSI implementation of DCT coefficients are also important issues. The removal of the block artifacts and faster DCT computation are therefore of practical interest. In this paper, we outline a modified DCT computation scheme that provides a simple efficient solution to the reduction of the block artifacts while achieving faster computation. We also derive a similar solution for the efficient computation of the inverse DCT. We have applied the new approach for the low-bit rate coding and decoding of images. Intial simulation results on real images have verified the improved performance obtained using the proposed method over the standard JPEG method.
Dosimetric and Microdosimetric Characteristics of 9.6 to 30α-MeV Proton Beams
Mitra Ghergherehchi,채종서,Hossein Afarideh,Ahmad Mohammadzadeh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.5
High and intermediate energy protons are not able to directly form a track in an etch detector (TED). Such detectors can, however, be used for the detection and dosimetry of beams of these particles through the registration of secondary charged particles with sufficiently high values of linear energy transfer (LET).Intermediate energy protons (10 to 30 MeV) with low LET values ranging from 5.87 down to 2.40 keV/탆 are considered. Although the LET values are low, this energy range seems to be sufficient to create secondary particles with much higher LET values through nuclear reactions in the irradiated matter. This phenomenon can modify the characteristics of the energy transfer process due to these particles, and it should be taken into account when such particles are used for radiobiology and/or radiotherapy studies. The importance of these secondary particles was studied experimentally by means of a LET spectrometer based on a chemically etched track detector, in which the tracks of the primary protons are not revealed. These studies were performed with protons whose primary energies were in the range of about 10 to 30 MeV, which are available at the Cyclotron Accelerator Department of Nuclear Research Center for Agriculture and Medicine (NRCAM) in Karaj, Iran. The microdosimetric distributions of the secondary particles mentioned above are presented, and their contributions to the absorbed dose of the primary protons are estimated. The contribution of the secondary particle dose increases with decreasing proton energy. The importance of this phenomenon in some applications is discussed. The origin of the secondary particles in interactions with protons having high and intermediate energies due to various nuclear reactions was calculated by using the Alice computer code. There is good agreement between the experimentally obtained and theoretically calculated results.
Mitra Ghergherehchi,Xiang-Jie Mu,채종서,김윤상 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.9
Makrofol DE1-4C detectors were exposed to fission fragments and alpha particles (of energy 0.5 -3 MeV) from a 252Cf source in a vacuum chamber. The exposed detectors were etched in 6-N NaOHsolution at 70 C to measure etch induction times. An optical microscope was used to investigatevarious charged particle tracks and diameters in Makrofol detectors. The etch induction times foralpha-particle and fission-fragment tracks were obtained from the intersections of extrapolations ofa graph of track diameters with time. The obtained results will be very useful in nuclear trackstudies, as well as nanotechnology fields.
( Mitra Alaee ) 범태평양응용언어학회 2015 범태평양응용언어학회지 Vol.19 No.2
The main purpose of the study was to investigate the relationship between Iranian EFL teachers`` Professional Identity and their types of Multiple Intelligences. Moreover, it aimed to see the extent to which their multiple intelligences can predict their professional identity. The participants of the study were 137 Iranian EFL teachers teaching in language schools of Semnan province. Professional identity questionnaire and multiple intelligence survey were used to collect the data. The results of correlation analysis indicated that there is a relationship between language teachers`` professional identity and their type of multiple intelligences, the highest one belonging to kinesthetic intelligence representing a large effect size. The results of linear regression showed that teachers`` multiple intelligence type can predict their professional identity. After, excluding the linguistics intelligence which did not contribute to the regression model significantly, the remaining seven multiple intelligences predicted 63.7 percent of professional identity. Pedagogical implications and suggestions for further studies are presented.
Mitra Arman,Kiana Pirian,Mostafa Alinaghizadeh,Fatemeh Khosheghbal,Reza Nahavandi,Saeid Tamadoni Jahromi 경희대학교 융합한의과학연구소 2022 Oriental Pharmacy and Experimental Medicine Vol.22 No.4
Nowadays, the essential oil has received a special position for the treatment of diseases. Although Satureja rechingeri Jamzad is an endemic species of Iran, unfortunately few studies have been conducted on its biological properties. In this study, along with the analysis of the compounds of Satureja rechingeri essential oil, cytotoxic, antioxidant and antibacterial properties of the essential oil of this species were investigated. The compounds of prepared essential oil were analyzed by GC-FID and GC–MS using Clevenger. Disc diffusion and MTT methods were used to determine the antibacterial activity and cytotoxicity of the essential oil, respectively. The antioxidant activity of the essential oil was measured by two methods of reducing power assay and DPPH free radical scavenging. p-Cymene (46.5%) was the most identified compound in the essential oil. The essential oil showed higher inhibitory effect on seven bacterial strains relative to the standard antibiotics. The studied essential oil showed significant concentration-dependent inhibitory effect on four cancer cells of Vero, SW480, MCF7 and JET3 with 50% lethal effect of 15.6, 125, 15.6 and 250 μg/mL for each line, respectively. The highest adsorption (2.6 nM) was at 500 μg/mL for reducing power assay and 50% free radical inhibition at a concentration of 375 μg/mL for DPPH antioxidant assay. In general, the essential oil of Satureja rechingeri with high antioxidant, antibacterial and anticancer activity can be used as a cheap and affordable natural product in clinical and pharmaceutical fields.
Study of federated learning in industrial IoT
Mitra Pooyandeh,Insoo Sohn 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.11
The Industrial Internet of Things (IIoT) is actually a subset of IoT. Therefore, the growing development of IoT technology in recent years and its application in the industry have improved the performance of various industries. Certainly, the extensive usage of IoT in industrial is led to producing a huge amount of data that require a server for processing. while sending this amount of data causes several issues such as data centralization and privacy-preserving. Federated learning (FL) is an exhaustive solution to overcome these problems. Given that federated learning technology implemented in IIoT keep the data on the device as result, it helps the data security and optimizes the communication cost. In this article, we present a study of FL in IIoT.