• Resources Recycling
• /
• v.30 no.5
• /
• pp.38-48
• /
• 2021

In this study, we determine the optimal process conditions for selectively recovering Si from a solar cell surface by removal of impurities (Al, Zn, Ag, etc.). To selectively recover Si from solar cells, leaching is performed using HCl solution and an ultrasonic cleaner. After leaching, the solar cells are washed using distilled water and dried in an oven. Decompression filtration is performed on the HCl solution, and ICP-OES (Inductively Coupled Plasma Optical Emission spectroscopy) full scan analysis is performed on the filtered solution. Furthermore, XRD (X-ray powder diffraction), XRF (X-ray fluorescence), and ICP-OES are performed on the dried solar cells after crushing, and the purity and recovery rate of Si are obtained. In this experiment, the concentration of acid solution, reaction temperature, reaction time, and ultrasonic intensity are considered as variables. The results show that the optimal process conditions for the selective recovery of Si from the solar cells are as follows: the concentration of acid solution = 3 M HCl, reaction temperature = 60℃, reaction time = 120 min, and ultrasonic intensity = 150 W. Further, the Si purity and recovery rate are 99.85 and 99.24%, respectively.

• Ecology and Resilient Infrastructure
• /
• v.8 no.4
• /
• pp.194-203
• /
• 2021

With the recent increase in maintenance works on water and sewer pipes as well as district heating supply pipes, pavement cutting work using pavement cutter is on the rise. The pavement cutting operation generates considerable dust (cutting sludge) as well as noise; therefore, it is necessary to apply eco-friendly technologies that have low noise and dust recovery capability. Thus far, various equipment for recovering dust have been developed; however, there is a limitation in that the environmental friendliness is not quantified. Therefore, in this study, we developed a low-noise, dust-recovery type pavement cutter that can fundamentally remove the causes of environmental hazards such as noise and dust and evaluated the eco-friendliness of the pavement cutting process performed by this cutter. To this end, an integrated water cooling-sludge recovery system composed of a vacuum device and a sludge suction unit was developed, and the developed system was applied to a pavement cutter. Subsequently, the developed equipment was applied to the test bed, and data related to its eco-friendliness were collected and evaluated. The results showed that the cutting sludge recovery rate of the developed equipment was greater than 83%, the noise level was approximately 82 - 83 dB, and the sound power level was 115 dB. The results of this study will be used as basic data to develop improved pavement cutters in the future with improved cutting sludge recovery performance and lower noise.

• Journal of the Korean GEO-environmental Society
• /
• v.20 no.5
• /
• pp.31-38
• /
• 2019

Recently, there has been an increasing number of ground subsidence (sink-hole) in the downtown areas, and in such a case, it is important to minimize accidents and passages through prompt recovery. With respect to the present recovery method for ground subsidence, the methods of applying the back filling after excavating the ground subsidence or using the grouting injected materials to restore the ground are mostly used, but there has been few studies on materials used for recovering the ground subsidence. Therefore, in order to clarify the characteristics of back filling materials used in the ground subsidence, this study uses the environment-friendly hardening agent to improve the dredged clay, and then, the mixture ratio of hardening agent and mixture ratio of decomposed granite soil is changed to cure for 3, 7, 14 and 28 days to analyze the intensity characteristics of the unconfined compression, and it was compared with the unconfined compression intensity for the previously used cement, a hardening agent. In order to evaluate the characteristics of intensity on the back filling materials, the C.B.R test was carried out, and for the review on whether the back filling materials influence on corrosion of water and sewer pipes and others, the soil non-resistance test was carried out. As a result of the test, for the case of the recovery work of the ground subsidence that requires urgency, it is considered as prudent if the hardening agents of 12% are integrated to cure for 3 days or longer, and for not having the influence on the corrosion of the gas tube or water pipes, it is proposed to mix for 30% or more of the decomposed granite soil. Door model test were conducted To confirm the bearing capacity characteristics of the solidified layer.

• Journal of Convergence for Information Technology
• /
• v.9 no.3
• /
• pp.112-119
• /
• 2019

This study examined the role of citizen advocates in advocating for people with developmental disabilities. Citizen advocacy refers to activities that advocate and represent citizens on behalf of those who are socially vulnerable. The purpose of this study is to analyze the role concept of citizen advocates by conducting focus group interviews and dividing the 13 citizen advocates with developmental disabilities into 4 groups. It is divided into four main subjects and nine sub-themes. The main theme are 'Self-transformation of the parties', 'Restoring the rights of the parties', 'Being with the parties', and 'Expanding the world of the parties'. Sub-themes are 'Recognizing and solving the problem of self', 'Granting role to speak', 'Recovering the initiative of service use', 'Restoring the rights of existing (family and neighbor), "Preventing money harm" "Speaking instead", "Encouraging and petting people", "Promoting change in the community", and "Expanding the size of the world a little bit". Based on this, we discussed the importance of citizen advocacy as a preventive advocacy system, the relationship between citizen advocacy and professional advocacy system, the difference between volunteer and personal assistants and citizen advocacy, and considerations for citizen advocacy.

• Journal of Positioning, Navigation, and Timing
• /
• v.7 no.4
• /
• pp.295-305
• /
• 2018

Network RTK is a highly practical technology that can provide high positioning accuracy at levels between cm~dm regardless of user location in the network by extending the available range of RTK using reference station network. In particular, unlike other carrier-based positioning techniques such as PPP, users are able to acquire high-accuracy positions within a short initialization time of a few or tens of seconds, which increases its value as a future navigation system. However, corrections must be continuously received to maintain a high level of positioning accuracy, and when a time delay of more than 30 seconds occurs, the accuracy may be reduced to the code-based positioning level of meters. In case of SSR, which is currently in the process of standardization for PPP service, the corrections by each error source are transmitted in different transmission intervals, and the rate of change of each correction is transmitted together to compensate the time delay. Using these features of SSR correction is expected to reduce the performance degradation even if users do not receive the network RTK corrections for more than 30 seconds. In this paper, the simulation data were generated from 5 domestic reference stations in Gunwi, Yeongdoek, Daegu, Gimcheon, and Yecheon, and the network RTK and SSR corrections were generated for the corresponding data and applied to the simulation data from Cheongsong reference station, assumed as the user. As a result of the experiment assuming 30 seconds of missing data, the positioning performance compensating for time delay by SSR was analyzed to be horizontal RMS (about 5 cm) and vertical RMS (about 8 cm), and the 95% error was 8.7 cm horizontal and 1cm vertical. This is a significant amount when compared to the horizontal and vertical RMS of 0.3 cm and 0.6 cm, respectively, for Network RTK without time delay for the same data, but is considerably smaller compared to the 0.5 ~ 1 m accuracy level of DGPS or SBAS. Therefore, maintaining Network RTK mode using SSR rather than switching to code-based DGPS or SBAS mode due to failure to receive the network RTK corrections for 30 seconds is considered to be favorable in terms of maintaining position accuracy and recovering performance by quickly resolving the integer ambiguity when the communication channel is recovered.

• Resources Recycling
• /
• v.27 no.6
• /
• pp.68-75
• /
• 2018

The rare earth elements (REE) contents in coal ashes generated from domestic circulating fluidized bed combustion (CFBC) were identified for evaluating the exploitation possibilities for recovering rare earth elements. Total REE contents for all of the samples in this study ranged from 82.2 ~ 311.7 ppm, much lower than the 403.5 ppm given on the average value of world coal ash. As a result of analysis using REE concentration and Outlook coefficient, six types of coal ashes falls in the unpromising area (I). These results suggest that it is difficult to recover rare earth element from coal ashes at this stage. It has been confirmed that to recover rare earth elements in coal ashes, research on the pretreatment and concentration process for critical REE is requirement.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.498-506
• /
• 2018

The purpose of this study is to examine the restorative effect of Semisulcospira libertina extract, on damaged liver cells induced by D-galactosamine in rats. Treatment of damaged liver cells with S. libertina extract significantly reduced local fatty degeneration, and inflammatory cell necrosis, to levels similar with the undamaged control group. In addition, S. libertina extracts were found to reduce plasma levels of liver damage indicator enzymes, such as AST, ALT, LDH and ALP, to control levels. It also reduced lipid peroxides, and lipid contents within damaged liver tissues. This suggests that S. libertina extract has a restorative effect on liver cells, thus reducing release of damage-associated liver enzymes, and oxidative degradation of lipids. Also, S. libertina extracts were found to be involved in recovery of damaged cells from inflammatory response by suppressing expression of $TNF-{\alpha}$, which leads to tissue injury and necrosis, whereas inducing expression of HO-1 that protects cells during inflammation. Thus, S. libertina extract restores liver tissue from necrosis and fibrosis, as well modulates expression of inflammation-related genes against liver damage. Our findings suggest that S. libertina extract is an effective medicinal resource, for improving and recovering liver cells from hepatic injury.

• Korean Journal of Heritage: History & Science
• /
• v.42 no.4
• /
• pp.50-73
• /
• 2009

Recently old stone walls were designated as registered cultural properties that meant an extension of categories about cultural properties from a spot area to whole area. Moreover given the changing situation of residential pattern, which is due to rapid social change, this designation can be seen as a significant measure to keep as intact as possible traditional landscapes in agricultural and fishing villages. In this paper, I analyze the symbol system and meaning of old stone walls and attempt to pick out the cultural elements which are related to them. These days we have made efforts to various aspects for which make traditional cultural resources into cultural contents. But many studies had done before emphasized aspects for beauty only. Especially existing studies about an old stone wall was mainly focused on architectural interpretation and tourist route. So we need to build a plot around oral research and need a creative approach for sharing with tourists. Cultural contents combine the original form, potential and capabilities with media by detecting original form of culture and finding out the worth and meaning. In this paper examined the probability of using by investigating a stone wall in Sang-hak Village that is related with recovering of places to live in contemporary society and finding cultural contents. I suggest more creative ways to make cultural properties into tourist resources by considering the possibilities of place marketing using storytelling, based on an analysis of data gathered.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.32 no.3
• /
• pp.23-36
• /
• 2019

Objectives : The purpose of this study is to confirm the efficacy and safety of "Functional cosmetics containing peptide Scolopendrasin-I isolated from the Scolopendra subspinipes mutilans" on dry skin due to mild atopic dermatitis. Methods : A total of 24 patients who visited Semyung Oriental Medical Center from November 1st, 2018 to December 20th, 2018 were included in the study. In this study, the patients were treated with Functional cosmetics containing peptide Scolopendrasin-I isolated from the Scolopendra subspinipes mutilans. For 4 weeks of gross examination, instrumental assessment were made before and after the study to evaluate how well the products for treatment group in recovering the dry skin barriers by mild atopic dermatitis. Results : 1. In the primary endpoint, Skin Hydration showed a statistically significant increase in treatment group in baseline, 2 weeks and 4 weeks. 2. In the primary endpoint, Transepidermal Water Loss(TEWL) showed a statistically significant decrease in treatment group between Baseline and 4 weeks. 3. In the secondary endpoint, Skin pH showed a statistically significant decrease in treatment group between baseline and 4 weeks. 4. To evaluate the safety of the products for the human body, Adverse events, SCORAD Index Assessment were conducted; There were no severe adverse events during this study. And SCORAD Index showed a statistically significant decrease in treatment group in baseline, 2 weeks and 4 weeks. Therefore, it is suggested that products, if used for certain period, should be safe for the human body. Conclusions : According to the above experiments, it is suggested that "Functional cosmetics containing peptide Scolopendrasin-I isolated from the Scolopendra subspinipes mutilans" should be effective for dry skin due to mild atopic dermatitis.

• Resources Recycling
• /
• v.28 no.4
• /
• pp.30-36
• /
• 2019

In this study, Li powder was recovered from the by-product of LNO ($Li_2NiO_2$) process, which is the positive electrode active material of waste lithium ion battery, through the $CO_2$ thermal reaction process. In the process of recovering Li powder, the $CO_2$ injection amount is 300 cc/min. The $Li_2NiO_2$ award was phase-separated into the $Li_2CO_3$ phase and the NiO phase by holding at $600^{\circ}C$ for 1 min. After this, the collected sample:distilled water = 1:50 weight ratio, and after leaching, the solution was subjected to vacuum filtration to recover $Li_2CO_3$ from the solution, and the NiO powder was recovered. In order to increase the purity of Ni, it was maintained in $H_2$ atmosphere for 3 hours to reduce NiO to Ni. Through the above-mentioned steps, the purity of Li was 2290 ppm and the recovery was 92.74% from the solution, and Ni was finally produced 90.1% purity, 92.6% recovery.