Tomographic density imaging using modifi ed DF–DBIM approach

Tran Quang Huy,Nguyen Thi Cuc,Van Dung Nguyen,Ton That Long,Tran Duc Tan 대한의용생체공학회 2019 Biomedical Engineering Letters (BMEL) Vol.9 No.4

Ultrasonic computed tomography based on back scattering theory is the most powerful and accurate tool in ultrasound basedimaging approaches because it is capable of providing quantitative information about the imaged target and detects verysmall targets. The duple-frequency distorted Born iterative method (DF–DBIM), which uses density information along withsound contrast for imaging, is a promising approach for imaging targets at the level of biological tissues. With two frequenciesf 1 (low) and f 2 (high) through 1and 2iterations respectively, this method is used to estimate target density along withsound contrast. The implications of duple-frequency fusion for the image reconstruction quality of density information alongwith sound contrast based ultrasound tomography have been analyzed in this paper. In this paper, we concentrate on theselection of parameters that is supposed to be the best to improve the reconstruction quality of ultrasound tomography. Whenthere are restraints imposed on simulated scenarios to have control of the computational cost, the iteration number 1isdetermined resulting in giving the best performance. The DF–DBIM is only eff ective if there are a moderate number of iterations,transmitters and receivers. In case that the number of transducers is either too large or too small, a result of reconstructionwhich is better than that of the single frequency approach is not produced by the implementation of DF–DBIM. A fi xedsum of 1and 2was given, the investigation of simulation results shows that the best value of 1is[2− 1]. Theerror, when applying this way of choosing the parameters, will be normalized with the reduction of 56.11%, compared touse single frequency as used in the conventional DBIM method. The target density along with sound contrast is used to imagetargets in this paper. It is a fact that low-frequency off ers fi ne convergence, and high-frequency off ers fi ne spatial resolution. Wherefore, this technique can eff ectively expand DBIM’s applicability to the problem of biological tissue reconstruction. Thanks to the usage of empirical data, this work will be further developed prior to its application in reality.

Nano-sized hematite-assembled carbon spheres for effectively adsorbing paracetamol in water: Important role of iron

Loc Ton That,Dat Nguyen Duy,Tran Hai Nguyen 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12

This study developed a new α-Fe2O3 (hematite) nanoparticles-loaded spherical biochar (H-SB) through the direct pyrolysis of glucose-derived spherical hydrochar and FeCl3. The optimal impregnation ratio (hydrochar and FeCl3) was 1/1.25 (wt/wt). H-SB was applied to remove paracetamol (PRC) from water. Results indicated that H-SB exhibited a relatively low surface area (127 m2/g) and total pore volume (0.089 cm3/g). The presence of iron particles in its surface was confirmed by scanning electron microscopy with energy dispersive spectroscopy. The dominant form of iron nanoparticles (α-Fe2O3) in its surface was confirmed by X-ray powder diffraction and Raman spectrum. The crystallite size of α-Fe2O3 in H-SB was 27.4 nm. The saturation magnetization of H-SB was 6.729 cmu/g. The analysis of Fourier-transform infrared spectroscopy demonstrated that the C-O and O-H groups were mainly responsible for loading α-Fe2O3 nanoparticles in its surface. The adsorption study indicated the amount of PRC adsorbed by H-SB slightly decreased within solution pH from 2 to 11. The adsorption reached a fast saturation after 120 min. The Langmuir maximum adsorption capacity of H-SB was 49.9 mg/g at 25 °C and pH 7.0. Ion-dipole interaction and π-π interaction played an important role in adsorption mechanisms, while hydrogen bonding and pore filling were minor. Therefore, H-SB can serve as a promising material for treating PRC-contaminated water streams.

Trends in prediabetes and diabetes prevalence and associated risk factors in Vietnamese adults

That Thanh Ton,Anh Thi Ngoc Tran,Ich Thanh Do,Hoa Nguyen,Thi Thanh Binh Nguyen,Minh Tu Nguyen,Van Anh Bao Ha,Anh Quoc Tran,Huu Khoi Hoang,Binh Thang Tran 한국역학회 2020 Epidemiology and Health Vol.42 No.-

OBJECTIVES: The prevalence of diabetes mellitus is rapidly increasing in Vietnam, particularly among adults aged over 45 years. This study estimated trends in diabetes and prediabetes prevalence and determined risk factors in Vietnamese adults (over 45 years). METHODS: A cross-sectional study was conducted based on data from an annual diabetes screening program among people aged 45-69 years in an urban city in central Vietnam (Da Nang). Joinpoint regression analyses were performed to calculate the annual percentage change and ptrend-values. Multinomial logistic regression analysis was used to determine risk factors. RESULTS: In total, 3,765 men and 9,149 women were included in this analysis. The age-adjusted prevalence of diabetes and prediabetes in 2017 was 11.4% and 52.9%, respectively. The prevalence of diabetes was higher in men (15.1%) than in women (10.3%), but that of prediabetes was similar in both genders (53.4% vs. 52.8%). The prevalence of prediabetes significantly increased during the study period, whereas no upward or downward trend for diabetes was observed. The prevalence of obesity, abdominal obesity, hypertension, and dyslipidemia showed no obvious trend. Obesity, a high waist-to-hip ratio, hypertension, more severe abdominal obesity, and dyslipidemia were significantly associated with a higher risk of diabetes and prediabetes. CONCLUSIONS: Diabetes and prediabetes were more prevalent among people aged over 45 years than in the general population. Da Nang has experienced a marked increase in the prevalence of prediabetes. These findings have significant implications regarding the need for nationwide public health interventions and management aiming at diabetes prevention and control.

Mathematical Models That Underlie Computer Simulation of the Hook and Line Fishing Gears

Mathematical Models That Underlie Computer Simulation of the Hook,Vasilii Vladimirovich Kudakaev 한국해양과학기술원 2019 Ocean and Polar Research Vol.41 No.1

he present study obtained universal mathematical models of all elements and characteristics regarding hook and line fishing systems. To describe the hook and line fishing systems on site we used three kinds of coordinate systems: the earth based coordinate system, natural coordinate system, and flow (velocity) coordinate system. Mathematical models presented in this article allow us to define the shape of the fishing gear, the tension of the rope at different points, hydrodynamic resistance, diameter of the hook’s wire, immersion depth of the fishing hooks, distance from hooks to the ground and the required lifting force of the floats. These models allow for the performance of computer simulations regarding any kinds of hook and line gears in still water or water where flow occurs.

Review on Thermoset-carbon Nanotube Nanocomposites

Ton-that Minh Tan The Korean Powder Metallurgy Institute 2005 한국분말재료학회지 (KPMI) Vol.12 No.2

SiC MOSFET Compared to Si Power Devices during Short Circuit Test

Nguyen Thanh That(탄탓),Ashraf Ahmed(아쉬라프 아흐무드),Park Joung Hu(박종후) 전력전자학회 2013 전력전자학술대회 논문집 Vol.2013 No.11

Composites derived from synthetic clay and carbon sphere: Preparation, characterization, and application for dye decontamination

Nguyen Duy Dat,Ton That Loc,Mai Thuan Trieu,Dong Thanh Nguyen,Khuong Quoc Nguyen,My Linh Nguyen,Anh Duy Duong Le,Hai Nguyen Tran 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.4

Two new composites from synthetic clay-like materials and carbon spheres were developed. Layered doubledhydroxides (LDH) were synthesized from the coprecipitation of Mg2+ and Al3+ ions. Spherical hydrochar (SH) wasprepared from pure glucose through hydrothermal carbonization at 190 oC. The composite LDH–SH was synthesizedthrough a simple hydrothermal method of the mixture of LDH and SH. Another composite, LDO-SB, was directly preparedthrough the carbonization of LDH-SH at 500 oC. Under such high temperature, LDH was converted to layereddoubled oxides (LDO), and SH was transferred to spherical biochar (SB). Those materials were characterized by chemicalstability, surface morphology and element composition, crystal structure, surface functional group, and texturalcharacteristic. They were applied for removing cationic dye (methylene blue; MB) and anionic dye (Congo red; CR)under different pH solutions. Three adsorption components—kinetics, isotherm, and thermodynamics—were conductedunder batch experimenters. Results demonstrated that the LDH or LDO particles were assembled on the surfaceof SH or SB, respectively. The surface area, total pore volume, and average pore width of LDH–SH and LDO-SBwere 58.5 and 198m2/g, 0.319 and 0.440 cm3/g, and 21.8 and 8.89 nm, respectively. The maximum adsorption capacityof the materials, calculated from the Langmuir model, at 30 oC for CR and MB dyes was 1589 and 78.6mg/g (LDOSB)and 499 and 226mg/g (LDH-SH), respectively. The composites exhibited a higher affinity to anionic than cationicdyes, which resulted from the great contribution of the clay-like materials. Therefore, they can serve as a promisingcomposite for the decolorization of wastewater.

Wet process and exfoliation of clay in epoxy

Tri-Dung Ngo,Minh-Tan Ton-That 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12

A new approach for the preparation of epoxy-clay nanocomposite (ECN) was developed based on utilization of water remains in the clay treatment as a carrier to improve clay dispersion and intercalation/exfoliation. A novel type organoclay was prepared by combining short and long chain molecule intercalants. The short chain intercalant provides the functionality ready to interact with the polymer, while the long one helps keep clay layers apart from each other. The micro- and nano-structures, physical and mechanical properties, and fire resistance of ECN were studied. The results indicated that the use of wet process and clay modification facilitates the dispersion intercalation/exfoliation of clay, the interaction between clay and epoxy, and subsequently improves ECN mechanical properties and fire resistance. The drying, grinding and screening steps in the preparation of organoclay could be eliminated, thereby reducing energy consumption. This method allows the solvent free in the preparation of ECN, which requires considerable time and cost for solvent removing. This also reduces ECN’s environmental impact.

Smart Fiber Bragg Grating Sensor System for Monitoring and Handling Bedridden Patients

Victor Foo Siang Fook,Emily Hao,Shiro Takahashi,Maniyeri Jayachandran,Pham Viet Thang,Aung Aung Phyo Wai,Mon Htwe That,Qiang Qiu,Biswas Jit 한국과학기술원 인간친화 복지 로봇 시스템 연구센터 2007 International Journal of Assistive Robotics and Me Vol.8 No.2

  This paper presents a novel smart Fiber Bragg Grating sensor system which automatically monitors the behaviour of bedridden patients and their vital signs such as pulse rate based on indicative spatio-temporal signature for adaptive intervention triggering and activity planning. In particular, we present the subtle design, fabrication, calibration, implementation and deployment issues of the FBG pressure sensors to be used in a home or hospital to prevent bedsore generation, patients falling out of the bed or chair, and life threatening situations such as patient"s pulse rate weakening, etc. In addition, we provide a reusable middleware support system by exploiting Semantic Web standards to enable a number of novel services that facilitate caregiving and clinical assessment of bedridden patients in a context enlightened fashion.

A Review on Occupational Safety and Health Activities Conducted under ILO/Korea Partnership Program across Countries in Asia

( Jung Keun Park ),( Ton That Khai ) 한국감성과학회 2014 춘계학술대회 Vol.2014 No.-

To review and share occupational safety and health (OSH) activities which, based on a view of Korea Occupational Safety and Health Agency (KOSHA), were conducted under the 2011-2012 ILO/Korea Partnership Program across countries in Asia and the Pacific, this study documented OSH activities performed by authors from July 2011 through December 2012. Among the OSH activities examined, three-selected activities were primarily described and discussed in the study which is still in progress. The activities are looked at, partly or wholly, on what and how they were designed and implemented and, also, on how they would contribute to the understanding of stakeholders as well as improvement of OSH in Asian countries.