• Journal of Electrochemical Science and Technology
• /
• 제15권1호
• /
• pp.190-197
• /
• 2024

A commercial PbO₂ mesh cylinder electrode was utilized as the anode for the electrochemical degradation of the textile effluent after the biological treatment with the titanium cylinder as the cathode in a self-made tube electrolyzer. The electrochemical performances of the PbO₂ electrode in tube electrolyzer under different initial pH, electrolyte flow rates, current densities and times of the electrochemical degradation were investigated. The experimental results illustrated that the PbO₂ electrode can reduce the chemical oxygen demand (COD) of the textile effluent from 94.0 mg L^-1 to 65.0 mg L^-1 with the current efficiency of 88.3%, the energy consumption of 27.7 kWh kg^-1 (per kilogram of degraded COD) and the carbon emissions of 18.0 kg CO₂ kg^-1 (per kilogram of degraded COD) under the optimal operating conditions. In addition, the COD of the textile effluent could be reduced from 94.0 mg L^-1 to 22.0 mg L^-1 after the fifth electrochemical degradation. Therefore, PbO₂ mesh cylinder electrode in the tube cylinder was promising for the electrochemical degradation of the textile effluent.

• 대한치과교정학회지
• /
• 제51권3호
• /
• pp.179-188
• /
• 2021

Objective: To evaluate the overall treatment effects in terms of the amount of uprighting with changes in the sagittal and vertical positions of mandibular molars after applying an orthodontic miniplate with a nickel-titanium (NiTi) reverse curve arch wire (biocreative reverse curve [BRC] system). Methods: A total of 30 female patients (mean age, 25.99 ± 8.96 years) were treated with the BRC system (mean BRC time, 10.3 ± 4.07 months). An I-shaped C-tube miniplate (Jin Biomed) was placed at the labial aspect for the alveolar bone of the mandibular incisors. A 0.017 × 0.025-inch NiTi reverse curve arch wire was engaged at the C-tube mini-plate anteriorly and the first and second premolars and molars posteriorly in the mandibular arch. Pre- and post-BRC lateral cephalograms were analyzed. A paired t-test was used to analyze the treatment effects of BRC. Results: The mandibular second molars were intrusively uprighted successfully by the BRC system. Distal uprighting with a controlled vertical dimension was noted on the first molars when they remained engaged in the BRC and the distal ends of the arch wire were laid on the second molars. The mandibular first and second premolars showed a slight extrusion. The changes in the mandibular incisors were unremarkable, while the mandibular molar angulation improved significantly. The lower occlusal plane rotated counterclockwise (MP-LOP: 1.13° ± 2.60°). Conclusions: The BRC system can provide very effective molar uprighting without compromising the position of the mandibular anterior teeth.

• 한국정밀공학회지
• /
• 제34권4호
• /
• pp.247-251
• /
• 2017

Titanium alloy has been widely used in the aerospace industry because of its high strength and good corrosion resistance. During cutting, the low thermal conductivity and high chemical reactivity of titanium generate a high cutting temperature and accelerates tool wear. To improve cutting tool life, cryogenic machining by using a liquid nitrogen (LN2) jet is suggested. In cryogenic jet cooling, evaporation of LN2 in the tank and transfer tube could cause pressure fluctuation and change the cooling rate. In this work, cooling uniformity is investigated in terms of liquid nitrogen jet pressure in cryogenic jet cooling during titanium alloy turning. Fluctuation of jet spraying pressure causes tool temperature to fluctuate. It is possible to suppress the fluctuation of the jet pressure and improve cooling by using a phase separator. Measuring tool temperature shows that consistent LN2 jet pressure improves cryogenic cooling uniformity.

• 한국환경과학회지
• /
• 제20권5호
• /
• pp.623-630
• /
• 2011

This study investigated the degradation of N, N-Dimethyl-4-nitrosoaniline (RNO, indicator of the generation of OH radical) by using dielectric barrier discharge (DBD) plasma. The DBD plasma reactor of this study consisted of a quartz dielectric tube, titanium discharge (inner) and ground (outer) electrode. The effect of shape (rod, spring and pipe) of ground electrode, diameter (9~30 mm) of ground electrode of spring shape and inside diameter (4~13 mm) of quartz tube, electrode diameter (1~4 mm), electrode materials (SUS, Ti, iron, Cu and W), height difference of discharge and ground electrode (1~15.5 cm) and gas flow rate (1~7 L/min) were evaluated. The experimental results showed that shape of ground electrode and materials of ground and discharge electrode were not influenced the RNO degradation. The thinner the diameter of discharge and ground electrode, the higher RNO degradation rate observed. The effect of height gap of discharge between ground electrode on RNO degradation was not high within the experimented value. Among the experimented parameters, inside diameter of quartz tube and gas flow rate were most important parameters which are influenced the decomposition of RNO. Optimum inside diameter of quartz tube and gas flow rate were 7 mm and 4 L/min, respectively.

• 대한치과교정학회지
• /
• 제42권5호
• /
• pp.270-278
• /
• 2012

In the correction of dental Class III molar relationship in skeletal Class II patients, uprighting of the mandibular posterior segments without opening the mandible is an important treatment objective. In the case reported herein, a C-tube miniplate fixed to the lower labial symphysis and connected with a nickel-titanium reverse-curved archwire provided effective uprighting of the lower molars, without the need of orthodontic appliances on the mandibular anteriors. Using this approach, an appropriate magnitude of force is exerted on the molars while avoiding any negative effect on the mandibular anteriors.

• 설비공학논문집
• /
• 제27권3호
• /
• pp.174-178
• /
• 2015

This paper describes a signal processing technique for identifying signals from defects by using an electromagnetic-ultrasonic guided waves method based on a magnetostrictive sensor that generates a torsional mode (T(0, 1)). Because this technique is based on the digital filtering, the filtered signals provide information on the relationship between the cutoff frequency of band-pass filter and the characteristic of defect signals in heat exchange tubes. To verify the performance of the technique, artificial defects with various thickness reduction ration and shape were machined in titanium tubes, and digital filtering results are reported. The results show that digital filtering provides information to the identify shape of defects and the contact condition between the tube and support ring. Therefore, the proposed technique has good potential as a tool for evaluating the integrity of heat exchange tubes.

• Imaging Science in Dentistry
• /
• 제54권2호
• /
• pp.191-199
• /
• 2024

Purpose: The aim of this study was to evaluate image artifacts in the vicinity of dental implants in cone-beam computed tomography (CBCT) scans obtained with different spatial orientations, tube current levels, and metal artifact reduction algorithm (MAR) conditions. Materials and Methods: One dental implant and 2 tubes filled with a radiopaque solution were placed in the posterior region of a mandible using a surgical guide to ensure parallel alignment. CBCT scans were acquired with the mandible in 2 spatial orientations in relation to the X-ray projection plane (standard and modified) at 3 tube current levels: 5, 8, and 11 mA. CBCT scans were repeated without the implant and were reconstructed with and without MAR. The mean voxel and noise values of each tube were obtained and compared using multi-way analysis of variance and the Tukey test(α=0.05). Results: Mean voxel values were significantly higher and noise values were significantly lower in the modified orientation than in the standard orientation (P<0.05). MAR activation and tube current levels did not show significant differences in most cases of the modified spatial orientation and in the absence of the dental implant (P>0.05). Conclusion: Modifying the spatial orientation of the head increased brightness and reduced spatial orientation noise in adjacent regions of a dental implant, with no influence from the tube current level and MAR.

• 한국압력기기공학회 논문집
• /
• 제4권2호
• /
• pp.50-56
• /
• 2008

The tubes in heat exchanger are typically made of copper alloy, stainless steel, carbon steel, titanium alloy material. Type-439 ferritic stainless steel is ferromagnetic material, and furnish higher heat transfer rates than austenitic stainless steels and higher resistance to corrosion-induced flaws. Ferritic stainless steel can be found in low-pressure(LP) feedwater heaters and moisture separator reheaters(MSRs) in turbine system. LP feedwater heaters generally utilize thin wall Type-439 stainless steel tubing, whereas MSRs typically employ a heavier wall tubing with integral fins. Service-induced damage can occur on the O.D(outside diameter) surface of Type-439 ferritic stainless steel tubing which is employed for MSRs tubing, and the most typical damage mechanism is vibration-induced tube-to-TSP(tube support plate) wear and fatigue cracking. The wear has been reported that occurs mainly on the OD surface. Accordingly, in this study, we have evaluated the flaw sizing capability of magnetic saturation eddy current technique using magnetic saturation probe and flawed specimen.

• 한국산학기술학회논문지
• /
• 제14권10호
• /
• pp.4658-4664
• /
• 2013

본 논문은 심층수 이용 열교환기 개발을 위해 열교환기의 구성 재질로서 티타늄, 알루미늄, 스테인리스, 철, 구리와 알루미늄의 전착코팅 관 등을 이용한 이중관 열교환 실험 장치를 구성하여 열교환 성능을 실험하였다. 기존 심층수 이용 열교환기는 대부분 티타늄 금속으로 이루어져 있다. 티타늄의 재질은 해양 심층수에 적합하나 고가의 금속이다. 티타늄 금속을 대체할 금속으로 알루미늄, 스테인리스, 철, 구리와 알루미늄 전착코팅 관 등을 고려하여 시험하였다. 또한 EES 프로그램을 사용하여 각 관들의 열전달률을 해석하고 이중관 열교환 실험결과와 비교 분석하였다. 열교환시의 성능에 대한 해석값과 실험값을 비교해 보았을 때 10% 내외의 오차범위 내에서 잘 일치하였다. 또한 티타늄 대비 구리관이 가장 좋은 결과치를 보였고 알루미늄 전착코팅 관은 다소 낮은 열전달 수치를 보여 주었으나, 전착처리된 코팅관의 내부식성이 우수한 것을 고려한다면 티타늄 대체가능성이 충분하다고 사료된다.

• 한국산학기술학회논문지
• /
• 제14권11호
• /
• pp.5377-5384
• /
• 2013

본 논문은 심층수용 열교환기 재질로 티타늄, 알루미늄, 스테인리스, 구리와 알루미늄을 코팅하여 재질의 특성 및 부식이 미치는 영향을 조사하기 위하여 이중관 열교환 실험장치를 활용하였다. 열교환기 재질은 티타늄, 스테인레스, 구리, 알루미늄, 카본 코팅된 알루미늄 등 6종이 비부식관과 부식관에 대하여 해석과 실험이 수행되었다. 해석은 EES 프로그램을 사용하였다. 부식의 영향을 살펴보기 위하여 부식 제조장치를 제작하고, 3.5%의 염수를 $70^{\circ}C$의 온도로 약 6주간 담가서 가속부식을 실시하였다. 부식된 관으로 이중관 열교환기의 성능실험을 실시하여 비부식관과 비교하였다. 실험결과로부터 티타늄을 대체용으로 알루미늄 코팅관(카본 블랙 $150{\mu}m$)의 가능성을 확인하였다.