A study on the denitrification of reverse osmosis(RO) concentrated wastewater from sewage reuse treatment plant in P city was conducted using waste desulfurization agent obtained from desulfurization process. Sulfur-based autotrophic denitrifying carrier comprises the predetermined amount of waste iron sulfide (FeS, Fe2S3), mine drainage sludge and elemental sulfur showing mesoporisity with 9.9 nm (99 Å) of average pore size. Sulfur denitrifying bacteria and sulfur reducing bacteria were implanted into the pores of sulfur denitrifying carrier. Nitrate was not affected by empty bed contact time (EBCT). It is probably due to larger reducing capacity of the carrier than the concentration of nitrate in RO concentrated wastewater. Total nitrogen (T-N) removal efficiency exhibited about 90% after 4 days. Sulfate ion was surprisingly decreased with sulfur autotropic process due to the reduction of sulfate ion to HS- and S2- by sulfur reducing bacteria. Sulfide and hydrogen sulfide ions were then taken by Fe(OH)3, main component of mine drainage sludge, releasing OH-. Alkalinity was therefore maintained between 7.5 and 8.5 in pH by the released OH-. Also, it had the effect of suppressing the production of H2S, which causes bad odor.

시멘트 콘크리트 포장의 양생 공정에서는 피막양생제를 살포하는 것이 가장 일반적이며 양생포와 같은 덮개를 콘크리트 포장 위에 덮어 온도와 습도를 유지하는 방법으로 콘크리트 포장의 강도를 발현시키기도 한다. 콘크리트 포장의 미끄럼 저항 및 배수, 주행안전 성을 향상시키기 위해서는 양생 공정 이전에 표면 타이닝 공정을 수행하는 것이 일반적이지만 양생 이후에 그루빙을 실시하기도 한다. 본 연구에서는 콘크리트 포장 품질에 지대한 영향을 주는 양생 작업과 표면 그루빙 작업의 일원화 방법 개발을 위한 기초 연구로써 3D 스케치 프로그램과 3D 프린터를 이용하여 타원형, 삼각형, 사각형 모양의 홈으로 그루빙을 형성하면서 동시에 양생포로 사용이 가 능한 그루빙 양생 플레이트를 설계하여 제작하였다. 그루빙 양생 플레이트의 적용성을 분석하기 위해 콘크리트 공시체를 제작하여 실 내 실험을 수행하였으며 양생 플레이트의 그루빙 홈 형상에 따른 콘크리트 포장 표면 그루빙 형성 상태를 분석하였다.

The condensation phenomenon can affect the product in terms of function and aesthetics, so it is a complaint of many users from the past, and continuous research has been conducted to solve it. A portable instrument panel is installed inside combat vehicles such as tanks and armored vehicles. Due to the nature of the combat vehicle operated in the special situation of battle, the internal heat generation of the instrument panel has increased significantly, which is presumed to be the cause of condensation inside the instrument panel. In this paper, a study on the development of subsequent processes was conducted to reduce the condensation phenomenon of the instrument panel for combat vehicles. In order to reduce the condensation phenomenon, the experiment was carried out by setting baking time and stabilization time as major factors. This paper is considered to be a reference research data for all systems in which similar assemblies are used as well as instrument panels for combat vehicles.

This study aims to evaluate the effectiveness of adding CNC parameter monitoring functionality using OPC UA to the existing HMI for CNC grinding machines, specifically focusing on maintaining machining precision for ferrous materials despite changes in grinding wheel diameter post-dressing. Three workpieces, each ground with different wheel diameters (WD162.24, WD162.22, WD162.20), were subjected to profile error measurements at various angles within a ±4.0μm tolerance range. The elliptical shape of the workpieces required diameter measurements across a 90-degree section. Results indicated that, despite slight deviations, all workpieces remained within the specified tolerance range, demonstrating that the OPC UA-based monitoring system effectively maintains machining precision after wheel dressing. This suggests significant potential for improving grinding processes for ferrous materials using OPC UA-integrated CNC systems.

This study explored effects of a sludge-based biochar addition on nitrogen removal of membrane bioreactor (MBR) for wastewater treatment. The membrane fouling reduction by the biochar addition was also investigated. A dose of 3 g/L of the biochar was applied to an MBR (i.e., BC-MBR) and treatment efficiencies of organic matter and nutrient were analyzed. The MBRs with powdered activated carbon (i.e., AC-MBR) and without any additives were also operated in parallel. The average removals of COD and TN were improved with the biochar addition compared to those with the control MBR. Interestingly, operational duration was also increased with biochar addition. The CLSM analysis revealed that biomass amounts of BC-MBR and AC-MBR were reduced by more than 40%, and thickness of the biofilm attached to the membrane surface also was decreased. The physical properties of biochar surfaces were compared with a commercial powdered activated carbon. The specific surface area with 38 m2/g and pore volume with 0.13 cm3/g of the biochar were much smaller than those of the powdered activated carbon, which were 1100 m2/g and 0.67 cm3/g, respectively. Manufacturing conditions for the biochar production needs to be further investigated for enhancing physical properties for adsorption and biological improvement.

We introduce the technology required todevelop a bracket process for installing and verifying FRT bumper sensors for passenger cars. Establish and demonstrate process automation through actual design and manufaturing. We conduct quality inspection of the production process using artificial intelligence and develop technology to automatically detect good and defective products and increase the reliability of the process

There are two primary sludge drying methods such as the direct heating microwave method and the indirect heating steam one. In this study, the drying treatment facility at sewage treatment plant A applied both of these drying methods. The research aimed to investigate the optimal operation approach for the drying facility, considering the input sludge and the moisture content data after the drying process. Moisture content and removal rate data were executed at the research facility from January 2016 to December 2018. First, the microwave, a direct heating drying method, performed intensive drying only on the outer surface of the sludge by directly applying heat to the sludge using far infrared rays, so effective sludge drying was not achieved. On the other hand, the steam method of the indirect heating method used steam from a gas boiler to maximize the utilization of the heat transfer area and reduce energy of the dryer, resulting in an effective sludge drying efficiency. The sludge moisture content brought into the sludge drying facility was about 80%, but the moisture content of the sludge that went through the drying facility was less than 10% of the design standard. Therefore, the steam method of the indirect heating method is more effective than the microwave method of the previous direct heating method and is more effective for maintenance It has proven that it is an efficient method of operating construction facilities.

The purpose of this study is to analyze the correlation between ecotoxicity and water quality items using Daphnia magna in public sewage treatment plant process and to obtain operational data to control ecotoxicity through research on removal efficiency. The average value of ecotoxicity was 1.39 TU in the influent, 1.50 TU in the grit chamber, and 0.84 TU in the primary settling tank and it was found that most organic matters, nitrogen, and phosphorus were removed through biological treatment in the bioreactor. Using Pearson’s correlation analysis, the positive correlation was confirmed in the order of ecotoxicity and water quality items TOC, BOD, T-N, NH3-N, SS, EC, and Cu. As a result of conducting a multilinear regression analysis with items representing positive correlation as independent variables, the regression model was found to be statistically significant, and the explanatory power of the regression model was about 81.6%. TOC was found to have a significant effect on ecotoxicity with B=0.009 (p<.001) and Cu with B=16.670 (p<.001), and since the B sign is positive (+), an increase of 1 in TOC increases the value of ecotoxicity by 0.009 and an increase in Cu by 1 increases the value of ecotoxicity by 16.670. TOC (β=0.789, p<.001) and Cu (β=0.209, p<.001) were found to have a significant positive effect on ecotoxicity. TOC and Cu have a great effect on ecotoxicity in the sewage treatment plant process, and it is judged that TOC and Cu should be considered preferentially and controlled in order to efficiently control ecotoxicity.

As environmental concerns escalate, the increase in recycling of aluminum scrap is notable within the aluminum alloy production sector. Precise control of essential components such as Al, Cu, and Si is crucial in aluminum alloy production. However, recycled metal products comprise various metal components, leading to inherent uncertainty in component concentrations. Thus, meticulous determination of input quantities of recycled metal products is necessary to adjust the composition ratio of components. This study proposes a stable input determination heuristic algorithm considering the uncertainty arising from utilizing recycled metal products. The objective is to minimize total costs while satisfying the desired component ratio in aluminum manufacturing processes. The proposed algorithm is designed to handle increased complexity due to introduced uncertainty. Validation of the proposed heuristic algorithm's effectiveness is conducted by comparing its performance with an algorithm mimicking the input determination method used in the field. The proposed heuristic algorithm demonstrates superior results compared to the field-mimicking algorithm and is anticipated to serve as a useful tool for decision-making in realistic scenarios.