In this study, using the plasma spray method, tensile and compression fatigue tests are performed in saline solution to examine the effect of Ti undercoat on corrosion fatigue behavior of alumina-coated specimens. The alumina-coated material using Ti in the undercoat shows better corrosion fatigue strength than the base material in the entire stress amplitude range. Fatigue cracking of UT specimens occurs in the recess formed by grit-blasting treatment and progresses toward the base metal. Subsequently, the undercoat is destroyed at a stage where the deformation of the undercoat cannot follow the crack opening displacement. The residual stress of the UT specimen has a tensile residual stress up to about 100 μm below the surface of the base material; however, when the depth exceeds 100 μm, the residual stress becomes a compressive residual stress. In addition, the inside of the spray coating film is compressive residual stress, which contributes to improving the fatigue strength characteristics. A hardened layer due to grit-blasting treatment is formed near the surface of the UT specimen, contributing to the improvement of the fatigue strength characteristics. Since the natural potential of Ti spray coating film is slightly higher than that of the base material, it exhibits excellent corrosion resistance; however, when physiological saline intrudes, a galvanic battery is formed and the base material corrodes preferentially.

The milk fever and mastitis that occur during the colostrum period in dairy cattle cause great damage in the dairy industry by causing a rapid decline in the cattle’s health and decreasing milk production. In order to prevent this, gradual milking (GM), calcium injection with gradual milking (CG), and calcium injection with complete milking (CC) methods are used. However, differences in effectiveness between these methods have not been established. Therefore, this study was conducted to determine the effects of each preventive method on milk fever and mastitis. The results of this study showed that while there was a significant negative correlation of GM with milk fever and mastitis (r = –0.657, p < 0.05), there was no correlation of CG and CC with milk fever and mastitis. The incidence of milk fever was significantly lower in CG and CC than in GM (p < 0.05) but no differences in the incidence of mastitis were observed between the three groups. No significant differences in the rate of recovery from milk fever and mastitis were observed between the three groups. The recurrence rate of milk fever was significantly higher in CG and CC than in GM (p < 0.05), though no differences in the recurrence rate of mastitis were observed. This study showed an inverse relationship between the incidence rates of milk fever and mastitis when calcium injection was not used during the colostrum period. When calcium injections were used, the incidence of milk fever was reduced without affecting the incidence of mastitis regardless of the milking method, but the recurrence rate of milk fever was increased. The results of this study would be useful for controlling blood calcium concentrations and establishing efficient milking strategy in order to effectively prevent milk fever and mastitis in dairy cattle during the colostrum period.

In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

Effective control of the heat generated from electronics and semiconductor devices requires a high thermal conductivity and a low thermal expansion coefficient appropriate for devices or modules. A method of reducing the thermal expansion coefficient of Cu has been suggested wherein a ceramic filler having a low thermal expansion coefficient is applied to Cu, which has high thermal conductivity. In this study, using pressureless sintering rather than costly pressure sintering, a polymer solution synthesis method was used to make nano-sized Cu powder for application to Cu matrix with an AlN filler. Due to the low sinterability, the sintered Cu prepared from commercial Cu powder included large pores inside the sintered bodies. A sintered Cu body with Zn, as a liquid phase sintering agent, was prepared by the polymer solution synthesis method for exclusion of pores, which affect thermal conductivity and thermal expansion. The pressureless sintered Cu bodies including Zn showed higher thermal conductivity (180 W/m·K) and lower thermal expansion coefficient (15.8×10−6/℃) than did the monolithic synthesized Cu sintered body.

This study was carried out to investigate the effect of the feeding method of total mixed fermentation (TMF) and concentrate feed on the growth performance, carcass and meat characteristics of late fattening Hanwoo steers. Twenty-four Hanwoo steers were used in this study. The control group was fed with concentrate feed + rice straw from the growing to the late fattening period, while the T1 group was fed with TMF from the growing to the early fattening period and concentrate feed + rice straw for the late fattening period. The T2 group was fed with TMF from the growing to the late fattening period. The average daily gain (ADG) and feed conversion ratio (FCR) were not different between the treatment and control group. Serum cholesterol and high density lipoprotein (HDL) cholesterol concentrations were higher in the T2 groups than in the control group (p<0.05). The yield grade and quality grade were not different between the treatment and control group. The lightness of longissimus muscle was higher in the T1 group than in the control and T2 groups (p<0.05). Poly-unsaturated fatty acid (PUFA) of longissimus muscle was increased in the T2 groups than in the control group. Therefore, the method of feeding TMF and concentrate feed could have a positive effect on the lightness and fatty acid composition of longissimus muscle without affecting the growth and carcass grades of Hanwoo steers.

In this study, we investigated the properties of adhesive materials with different lightweight materials such as CFRP and Al-foam. The specimens were tested and analyzed using DCB (Double Cantilever Beam) specimens. In order to secure the reliability of the finite element method, the test and analysis were carried out, and the reliability of the finite element method was secured by using the graph of reaction force to displacement based on the experiment and analysis. The study on the adhesive failure characteristics according to the position of notch hole proceeded. Notch holes were generated at the locations of 40, 110, 150 and 190 mm from the beginning of the specimen near the bonding interface, and the analysis conditions used were the same as those used for securing reliability. The obtained study results are compared with reaction force and equivalent stress. In the case of reaction force, the overall tendency is similar but the difference in maximum reaction force is found. It was found that higher reaction forces appeared at the beginning than at the end of the bonding interface. When the equivalent stresses in the specimens were examined, the value of CFRP was seen to be 30 times higher as much as that of Al-foam.

In this study, the BMI characteristics and food preference were examined according to the Sasang constitution typology. The constitution type of the subjects was judged by SCAT2 (SC) and Sasang specialists (SP), and the data were compared with the group (SS) in which the two results coincided. The results of SC and SP were consistent with 55 (38.2%) out of 144 subjects. Among the 55 subjects, there were 36 (65.5%), 15 (27.2%), and 4 (7.3%) Soeumin, Taeeumin, and Soyangin, respectively. The BMI of Taeeumin was significantly higher than that of Soeumin (p< .001) in all analytical methods. On the other hand, there was a difference in determining the body shape of Soyangin between the SCAT2 and specialists. The Taeeum-Soeum Food Preference Index was applied to compare the food preference to 41 types of food. In SS analysis, 13 kinds of foods preferred by Taeeumin or Soeumin were found, of which 8 (19.5%) were consistent with the existing food data. Taeeumin preferred 6 kinds of food, such as cold soybean-soup noodles, wild sesame seaweed soup, pan-fried tofu, Yeongun-jorim, Doraji-namul, and soy milk. In contrast, the favorite foods of Soeumin were black rice and Dak-galbi.

The impact of different mixing methods and sintering temperatures on the microstructure and piezoelectric properties of PZNN-PZT ceramics is investigated. To improve the sinterability and piezoelectric properties of these ceramics, the composition of 0.13Pb((Zn0.8Ni0.2)1/3Nb2/3)O3-0.87Pb(Zr0.5Ti0.5)O3 (PZNN-PZT) containing a Pb-based relaxor component is selected. Two methods are used to create the powder for the PZNN-PZT ceramics. The first involves blending all source powders at once, followed by calcination. The second involves the preferential creation of columbite as a precursor, by reacting NiO with Nb2O5 powder. Subsequently, PZNN-PZT powder can be prepared by mixing the columbite powder, PbO, and other components, followed by an additional calcination step. All the PZNNPZT powder samples in this study show a nearly-pure perovskite phase. High-density PZNN-PZT ceramics can be fabricated using powders prepared by a two-step calcination process, with the addition of 0.3 wt% MnO2 at even relatively low sintering temperatures from 800℃ to 1000℃. The grain size of the ceramics at sintering temperatures above 900℃ is increased to approximately 3 μm. The optimized PZNN-PZT piezoelectric ceramics show a piezoelectric constant (d33) of 360 pC/N, an electromechanical coupling factor (kp) of 0.61, and a quality factor (Qm) of 275.

Acoustic surveys were conducted in the seas surround the South Korea (South Sea A, South Sea B (waters around the Jeju Island), West Sea and East Sea) in spring and autumn in 2016. First, the vertical and horizontal distributions of fisheries resources animals were examined. In most cases vertical acoustic biomass was high in surface water and mid-water layers other than South Sea A in autumn and West Sea. The highest vertical acoustic biomass showed at the depth of 70-80 m in the South Sea A in spring (274.4 m2/nmi2) and the lowest one was 10-20 m in the West Sea in autumn (0.4 m2/nmi2). With regard to the horizontal distributions of fisheries resources animals, in the South Sea A, the acoustic biomass was high in eastern and central part of the South Sea and the northeast of Jeju Island (505.4-4099.1 m2/nmi2) in spring while it was high in eastern South Sea and the coastal water of Yeosu in autumn (1046.9-2958.3 m2/nmi2). In the South Sea B, the acoustic biomass was occurred high in the southern and western seas of Jeju Island in spring (201.0-1444.9 m2/nmi2) and in the southern of Jeju Island in autumn (203.7-1440.9 m2/nmi2). On the other hand, the West Sea showed very low acoustic biomass in spring (average NASC of 1.1 m2/nmi2), yet high acoustic biomass in the vicinity of 37 N in autumn (562.6-3764.2 m2/nmi2). The East Sea had high acoustic biomass in the coastal seas of Busan, Ulsan and Pohang in spring (258.7~976.4 m2/nmi2) and of Goseong, Gangneung, Donghae, Pohang and Busan in autumn (267.3-1196.3 m2/nmi2). During survey periods, fish schools were observed only in the South Sea A and the East Sea in spring and the West Sea in autumn. Fish schools in the South Sea A in spring were small size (333.2 ± 763.2 m2) but had a strong SV (–49.5 ± 5.3 dB). In the East Sea, fish schools in spring had low SV (–60.5 ± 14.5 dB) yet had large sizes (537.9 ± 1111.5 m2) and were distributed in the deep water depth (83.5 ± 33.5 m). Fish schools in the West Sea in autumn had strong SV (–49.6 ± 7.4 dB) and large sizes (507.1 ± 941.8 m2). It was the first time for three seas surrounded South Korea to be conducted by acoustic surveys to understand the distribution and aggregation characteristics of fisheries resources animals. The results of this study would be beneficially used for planning a future survey combined acoustic method and mid-water trawling, particularly deciding a survey location, a time period, and a targeting water depth.

This study was carried out to determine the optimal storage conditions by examining the effects of the storage conditions on the quality of red pepper powder during storage in households. Red pepper powder was stored at room temperature (20oC), refrigeration (2 and -1oC) and frozen (-5 and -20oC) for 3, 6, 9 and 12 months. The ASTA color value, capsanthin content and redness (a*) of the red pepper powders stored at -5 and -20oC were not decreased significantly depending on the storage temperatures until 9 months. The pH of red pepper powder stored at 20oC decreased significantly until 9 months and increased at 12 months. The microbiological quality of the red pepper powder stored at -5 and -20oC was more stable during long-term storage. In the sensory evaluation of red pepper powder stored under all conditions, the overall freshness, redness, hot flavor, moisture release, and edibility decreased with increasing storage period from the control to 12 months. Moisture release increased from 3 months to 12 months. Overall, red pepper should be stored at low temperatures (2 , -1oC) for up to 6 months, and frozen (≥ -5oC) for 6 to 9 months. The optimal temperature for long-term storage (≥9 months) was -20oC.

Metcalfa pruinosa was first reported in 2009 in Gimhae persimmon farms in Korea, and in Chungnam province in 2011, they first occurred in Dangjin and Taean. M. pruinosa adults are known to lay eggs among the crevices beneath the bark of the host plants, and they are reported to lay mainly on Robinia pseuroacacia trees. However, in order to solve the problem that the time and effort are too much to investigate by moving the 10 cm branch of R. pseudoacacia and removing the whole bark, we investigated the number of wintering eggs at different parts of branches from R. pseudoacacia and surveyed occurrence of them in Chungnam province. 14.5 times and 5.4 times more eggs were observed in the hair tissues of the twigs and thorms bases than the surface of R. pseudoacacia trees, respectively. There was no difference in the number of branches according to the thickness of branches. M. pruinosa in Chungnam province were mainly occurred in Taean, Geumsan and Dangjin, and showed patterns that occurred mainly in highways.

In membrane applications for wastewater treatment, polymeric membranes are dominant due to their processbility and low cost. To enlarge the membrane application in industrial effluent treatment, membrane materials with high mechanical and chemical tolerance should be needed. Although ceramics such as alumina would be good options for harsh environmental conditions, high cost and complex production methods hinder the application of ceramic membranes. Here, we demonstrate the preparation of cost-effective, robust alumina hollow fiber membranes (HFMs). Alumina HFMs prepared with phase inversion method followed by sintering showed narrow pore size distribution. Also, characteristics of the membrane can be easily tuned by controlling spinning and post treatment conditions.

In this study, we proposed a method for correcting non-compliance of the web standard in webpages based on the characteristics of sampled webpages. We collected about 70,000 webpages by using a web crawler and analyzed them by applying various statistical methods. We found that the top three most frequent types of errors and warnings consist of about 60% and 80% of the total number of errors and warnings, respectively. Based on these results, we focus on correcting four most frequent errors and warnings, and showed that the strategy corrected about 95% of these errors and warnings. In addition, we found that different types of errors and warnings are correlated in such a way that correcting one type of error or warning influences on the correction of another types.

2ZrO2·P2O5 powder, which is not synthesized by solid reaction method, was successfully synthesized through PVA solution method. In this process, the firing temperature and the PVA content strongly affected the crystallization behavior and final particle size. A stable α-phase 2ZrO2·P2O5 was synthesized at a firing temperature of 1200 oC and holding time of 4 h. β-phase 2ZrO2·P2O5 was observed, with un-reacted ZrO2 phases, for firing temperatures lower than 1200 oC. In terms of the PVA content effect, the powder prepared with a PVA mixing ratio of 12:1 showed stable α-phase 2ZrO2·P2O5; however, the β-phase was found to co-exist at relatively higher PVA content. The synthesized α-phase 2ZrO2·P2O5 powder showed an average particle size of 100~250 nm and an average thermal expansion coefficient of −2.5 × 10−6/oC in the range of room temp. ~800 oC.