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.

On Modeling and Simulation of AI-based IoT

Mitra Pooyandeh,Insoo Sohn(손인수) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6

Nowadays, the Internet of Things has become one of the essential technologies for connecting devices in the telecommunications, electricity, medical, automotive, and other industries. The Internet of Things includes an infinite set of connections and intelligent endpoints such as sensors, actuators, and so on. IoT devices, which include sensor networks with an unlimited number of sensors, face many problems, including power limitations and hardware limitations. Therefore, simulation is the best solution for changing and extending protocols in sensor networks. Furthermore, AI is becoming an important tool to solve problem related to IoT and hardware and power constraints. In this article, we review existing simulation and modeling tools and discuss including AI in the simulation.

Effect of Cu Layer Thickness on Giant Magnetoresistance Properties of NiCoFe/Cu/NiCoFe Sandwich

Mitra Djamal,Ramli,Yulkifli,Khairurrijal 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

The NiCoFe/Cu/NiCoFe sandwiches were grown onto Si (111) substrate by dc-opposed target magnetron sputtering (dc-OTMS) technique. The growth parameters are: temperature 100 <SUP>0</SUP>C, applied voltage 600 volt, flow rate of Ar gas 100 sccm, and growth pressure 5.2 x10<SUP>-1</SUP> Torr. The effects of Cu layer thickness on giant magnetoresistance (GMR) property of NiCoFe/Cu/NiCoFe sandwich were studied. We have found that the giant magnetoresistance (GMR) ratio is varied depend on the non-magnetic (Cu) layer thickness. The variation of Cu layer thickness of NiCoFe/Cu/NiCoFe sandwich presents an oscillatory behavior of GMR ratio. This oscillation reflects the exchange coupling oscillations between ferromagnetic and antiferromagnetic states, which are caused by an oscillation in the sign of the interlayer exchange coupling between ferromagnetic layers.

A Digital Twin-based Approach for Charge Estimation in Electric Vehicle

Mitra Pooyandeh,Insoo Sohn 한국통신학회 2023 한국통신학회 학술대회논문집 Vol.2023 No.6

Measurements of Nuclear Track Etch Induction Time in Markrofol for Alpha Particles from a 252-Cf Source

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.

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.

Comparison of temporomandibular disorders between menopausal and non-menopausal women

Mitra Farzin,Masumeh Taghva,Moslem Babooie 대한구강악안면외과학회 2018 대한구강악안면외과학회지 Vol.44 No.5

Objectives: Hormonal changes during menopause alter a woman’s susceptibility to some disorders. Information regarding the prevalence of temporomandibular disorder (TMD) in menopausal women is limited in the literature. In this study, the prevalence and severity of TMDs were compared between menopausal and non-menopausal women. Materials and Methods: The study included 140 women (69 premenopausal and 71 postmenopausal) 45 to 55 years of age that were examined in Shiraz Dental School, Shiraz in Iran. The Helkimo clinical dysfunction index (Di) was used to evaluate temporomandibular joint (TMJ) dysfunction. The data were analyzed using chi-square and Fisher’s exact tests. Results: Occurrence of TMD was significantly higher in menopausal than non-menopausal women (P<0.001). All the TMD criteria based on Helkimo Di except range of mandibular movement were significantly more common in menopausal women. The range of mandibular movement was not significantly different between menopausal and non-menopausal women (P=0.178). Conclusion: The results from this study show that TMD can be considered more common and severe in menopausal than non-menopausal women. This finding indicates that, similar to other conditions in menopausal women such as arthritis and osteoporosis, TMD should be taken into consideration by dental and medical professionals.

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.

Evaluation of Mechanical and Rheological Properties of Metronidazole Gel as Local Delivery System

Mitra Jelvehgari,Hassan Montazam 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.6

Rosacea is a chronic multifactorial vascular skin disorder that affects about 10 percent of the general population. Metronidazole is an effective antibiotic in the treatment of moderate-tosevere rosacea. Metronidazole is a suitable drug in cases of resistance to tetracycline or erythromycin, but it has also been shown that oral metronidazole may increase the side effects (e.g.,peripheral neuropathy). Oral metronidazole should not be used for more than three months, and hence topical metronidazole gel is the best therapeutic choice in rosacea (especially during pregnancy). This study examined the mechanical (adhesiveness, cohesiveness, extrudability, spreadability, homogeneity) and rheological (viscosity), skin irritant and drug release properties of different metronidazole gel formulations that contain anionic emulsifying wax, glycerin and lactic acid in different proportions. The release studies were conducted using Franz diffusion cells and Silastic membrane as a barrier. The results indicated that gel compressibility, hardness, and adhesiveness, are the factors that influence the ease of gel removal from the container, ease of gel application onto the mucosal membrane, and gel bioadhesion. The findings showed that there exists a strong negative correlation between the spreadability of a formulation and its cohesiveness, the spreadability of a formulation is inversely proportional to its cohesiveness. However, sorbitol solution (70%) concentration was not significantly correlated with drug release. In addition, drug release was significantly reduced as the concentration of anionic emulsifying wax increased and the concentration of lactic acid decreased. The maximum metronidazole release was achieved at a pH of 4-6. Data obtained from in vitro release studies were fitted to various kinetic models and high correlation was obtained in the Higuchi and first order models. The results showed that all the gel formulations showed good extrudability, viscosity, cohesiveness, homogeneity and spreadability.

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.