• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.755-762
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• 2007

For the evaluation of the load carrying capacity of the deteriorated PSC I girder bridge in service load state and the verification of the grade to the reinforcement effect of actual bridge strengthened by external prestressing tendons, the field test using vehicles is applied widely. Because this teat was executed in elastic range, the investigation of the characteristics of behavior caused by live load is only available. And it is impossible to estimate load carrying capacity in limit state and nonlinear behavior after that a crack is appeared. In this study, the 27-year-old prestressed concrete girder bridge is used and various load tests are performed, so we evaluate the behavior characteristics of the bridge in service load state and ultimate load state, and estimate the load carrying capacity of bridge. In addition, the artificial damages are induced from cutting internal tendons, and external tendons is added to strengthen it as much as vanished internal tendons. Next we compare the damage state with the strengthening state. In case of the application of external prestressing method to PSC I girder bridge, the present experiment result may decide more exactly the load carrying capacity of actual bridge, the amount for reinforcement, and the standard of quality control etc. at reinforcement work.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.315-323
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• 2000

Serious consequences can arise from lack of hygiene in mass catering. Microbiological testing is of value in determining hazards for developing a HACCP plan, and in demonstrating to food handlers the reality of the microbial risk. This studies was performed to describe the overall hygiene of cooking utensils and equipments, employees, and environment in mass catering establishments. Generally, hygienic conditions of cutting board and sanitized dish cloth were better than those of other cooking utensils such as knife, sieve, and peeler. It was found that the cross-contamination of knife might be caused by the use of contaminated sanitizing solution. It was observed that there was considerable variation (10$^1$~10$^{5}$ CFU) of the number of general bacteria for employee's hands. The number of general bacteria were influenced from establishment, employee, and the period of analysis. The number of Coliform group for employee's hands was in the range of 10$^2$~10$^4$CFU only at the first analysis. Total aerial bacteria in working area of mass catering establishments was below 7 CFU/Plate and aerial Staphylococcus sp. was not detected at all except one spot.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.167-176
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• 1997

A field experiment was conducted in Chungiu and Jungwon to evaluate growth characteristics, root development, dry matter yield, crude protein yield and palatability according to nitrogen fertilizer level at intercropping cultivation of sorghum $\times$ sudangrass hybrid(hereinafier referred as SSH) and soybean. Nitrogen level was six treatment of Okg, 30kg 60kg, 90kg 120kg, and 150kg per hectare, and cutting date (sorghum $\times$ sudangrass and soybean) was july 28. 1. In the SSH, plant length was increased with increasing nitrogen fertilizer from 0kg/ha to 120kg/ha, but 150kgha treatment was decreased cornpared to 120kg/ha treatment. In the soybean, plant length did not show difference among 0kg, 30kg 60kg, and 90kg per hectare, but 120kg and 150kgfha treatment was on the contrary short. In the SSH, leaf length, leaf width and leaf number were the highest in 120kg/ha treatment, but soybean showed multifarious. 2. Stem diameter of SSH was increased with increasing nitrogen fertilizer. But soybean was thick from 0kg/ha treatment to 60kg/ha treatment, while above 90kg/ha treatment was on the contrary thin. Stem of SSH was hard with increasing nitrogen fertilizer, but soybean was soft with increasing nitrogen fertilizer. Root weight (Dry matter) of SSH was increased with increasing nitrogen fertilizer. On the contrary, soybean was decreased with increasing nitrogen fertilizer. 3. In the dairy cattle and Korean native cattle, palatability according to nitrogen fertilizer was the highest at 90kgha treatment, while 120kgha treatment and 150kgha treatment was the lowest. But in the deer, 30kg/ha treatment of low nitrogen fertilizer was the highest in palatability. 4. Nitrogen content of root of SSH was increased with increasing nitrogen fertilizer(P<0.01). But in soybean, 30kg and 60kg/ha treatment were higher than 0kg, 90kg, 120kg and 150kg/ha treatment(P<0.01). Total niwogen content of soil were high at 90kg 120kg 150kgha trea~ment(P<0.01). 5. Dry matter yield was high at the 90kg 120kg and 150kgha treatment as range from 15, 262kg/ha to 15, 614kg/ha without significant difference among those, but Okgha treatment was the lowest as 11, 183kg/ha (PC 0.05). Protein content of SSH was the highest at 90kg/ha treatment as 8.3 percentage. Soybean was highest at 60kgha treatment as 22.9 percentage. Protein yield was the highest at 90kg/ha treatment as 1, 547.6kg/ha, but Okgha treatment was the lowest as 1, 022.8kg/ha (P<0.01).

• Horticultural Science & Technology
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• v.28 no.4
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• pp.580-584
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• 2010

The effect of planting densities on the growth of $Sedum$ $samentosum$ (4 collections) was investigated using nutrient film technique (NFT) with Yamazaki' lettuce nutrient solution (1982) from September 5th to October 24th in non-heating plastic film house. At 40 days, the plant height of 4 collections showed the range of 15.0-18.9 cm, and mean plant height was high the order of $10{\times}10$, $2.5{\times}2.5$, and $5{\times}5cm$. The growth of 'Pohang' and 'Wando' collections was better compared to that of 'Gunsan' and 'Wanju' collections. Number of node, stem diameter, and fresh and dry weight per plant were decreased in higher planting density. Despite the lower fresh weight per plant obtained, the fresh yield per $m^2$ was significantly increased in higher planting density. The mean fresh yield was $14.9kg{\cdot}m^{-2}$ in $2.5{\times}2.5cm$, and 'Pohang' collection showed the highest fresh yield ($17.6kg{\cdot}m^{-2}$). The first optimized harvesting time base on plant height was 30-40 days after NFT culture during autumn season. In eating quality, compression force of stem and bitterness of shoot were decreased in higher planting density. However, the heavy labor demanding high density cutting needs to be improved for hydroponic culture of $S.$ $samentosum$.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.447-460
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• 2016

Samples of Hangdeung granite and Berea sandstone containing sliding planes were prepared by saw-cutting and polishing using #100 or #600 grinding powders. Their basic friction angles were then measured directly in direct shear tests and triaxial compression tests, and also in tilt tests, which measure the angles indirectly. Although the angles measured by the direct methods were generally accurate, those measured along certain planes were greatly different from the others depending on the condition of the plane. The tilt tests yielded similar angles regardless of the sliding plane condition or the rock type; however, the error range was relatively wide. Sliding planes polished by the grinding powders yielded more accurate results than those cut by the saw and tested without polishing, as polishing ensured consistent conditions among all the planes. Sliding planes polished using #100 grinding powder yielded better results than polishing with #600 grinding powder. Therefore, the basic friction angles measured along the sliding planes polished using #100 grinding powder, as obtained in direct shear and triaxial compression tests, were the most reliable. The angle could also be measured satisfactorily by tilt testing along sliding planes polished with #100 grinding powder.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.4
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• pp.119-128
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• 2008

In this study, we attempted to seek out the ways to recycle fresh root-chips in the slope revegetation works by breaking tree root wastes occurring during the construction works, also to review the applicability of fresh root-chips as the soil media in slope revegetation works. For this purpose, we organized test units in order to investigate on-site applicability of fresh root-chips (broken chips). In order to examine the desirable ration of combining fresh root-chips with the hydroseeding soil media on the cutting slopes, we organized test units depending on the amount of combination. The following is the main experimental results. 1. At first, we analyzed properties of hrdro-seeding soil media and soil of the experimental sites. The overall results demonstrate that all the test units show proper range for vegetation. 2. We believe that the physical properties of soils in the earlier phase of restoration works on the sloped sites are not greatly affected by the fact whether broken chips exist or not. However, as time elapses, broken chips needs to be investigated further on what kind of impact they have on the soil condition. 3. More species are found in the test unit combining broken chips and we believe that it will contribute to blossoming of green plants and ecological succession of neighboring plants. 4. We performed experiment on possibility for fresh root-chips as substitutes for the hydro-seeding soil-media. In the test unit that combines fresh root-chips, its mixture ratio tends to exceed that of the test unit that does not combine fresh root-chips by 5 %. In case of the Thick-Layer-Soil-Media Hydroseeding works, the mixture ratio of the test unit that combines fresh root-chips after 16 weeks exceeds that of the test unit that does not combine fresh root-chips by 75%. 5. From the result of our experiment, it is obvious that the ratio of mixture and the number of emerging species are higher for the test unit combining fresh root-chips than the test unit that does not combine them. In other words, we can replace the hydro-seeding-soil-media with some Fresh root-chips without affecting the physical property of soil.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.33-38
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• 2010

A microfluidic system has been developed using biomaterial for the measurement of cupric ion concentration. The cell-membrane-mimicking bilayer lipid membrane(BLM)-coated silver electrode was used for the sensing of cupric ion concentration. The silver-supported BLM could increase its stability. A silver-supported bilayer lipid membrane(s-BLM) was easily obtained using its self-assembling characteristics by immersing silver wire into lipid(phosphatidylcholine; PC) solution and then dipping into aqueous KCl solution. These s-BLMs were used to determine the relationship between $Cu^{2+}$ concentration and current crossing s-BLM. Their relationship showed high linearity and reproducibility. The calibration curve was constructed to express the relationship between $Cu^{2+}$ concentration and current in the $Cu^{2+}$ concentration range of 10 and $130{\mu}M$. This calibration curve was used to measure $Cu^{2+}$ concentration in an unknown sample. Microfluidic system with s-BLM was made of PDMS(polydimethyl siloxane) using typical soft photolithography and molding technique. This integrated system has various functions such as activation of the silver surface without cutting silver wire, coating of BLM on silver surface, injection of KCl buffer solution, injection of $Cu^{2+}$ sample and measurement of $Cu^{2+}$ concentration in the sample.

• Journal of agricultural medicine and community health
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• v.26 no.2
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• pp.7-14
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• 2001

Cases of green tobacco sickness were described. During the cutting of tobacco plants throughout harvest, four cases of green tobacco sickness occurred in August 2001, Korea. The range of age was 42-55 years. The most frequent symptoms included dizziness, weakness, nausea, vomiting, abdominal cramps, headache, and difficulty breathing. All affected individuals worked in fields of wet tobacco, where their clothes became wet from moisture on the plants or sweating. They were all healthy, except one with hypertension. They are all non-smokers. They recovered after fluid and antiemetic administrations within two days. Most of doctors misdiagnosed their symptoms as a pesticide poisoning or heat injury. Green tobacco sickness is a condition that has long been known as an occupational health risk among tobacco harvesters. Nicotine poisoning by dermal absorption is reported to be the cause of green tobacco sickness. In Korea, there are many tobacco harvesters, and most of them may be sticken with green tobacco sickness. But, no case of green tobacco sickness has been reported. We report cases of green tobacco sickness occurred to the tobacco harvesters with a review of articles.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.07a
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• pp.25-37
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• 2002

The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.29-34
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• 2009

For several decades, many researchers have been involved in developing recycling methods for FRP boats. There are four basic classes of recycling covered in the literature. Despite of environmental problems(safety hazards), mechanical recycling of FRP boats, which involves shredding and grinding of the scrap FRP, is one of the simpler and more technically proven methods than incineration, reclamation or chemical ones. Because FRP is made up of reinforced fiber glass, it is very difficult to break into pieces. It also leads to secondary problem in recycling process, such as air pollution and unacceptable shredding noise level. Another serious problem of mechanical FRP recycling is very limited reusable applications for the residue. This study is to propose a new and efficient method which is more wide range applications and environment friendly waste FRP regenerating system. New system is added with the cyclone sorting machine for airborne pollutions and modified cutting system for several glass fiber chips sizes. It also has shown the FRP chip fiber-reinforced concrete and fiber-reinforced secondary concrete applications with the waste FRP boat to be more eligible than existing recycling method.