The effects of punching treatment on mycelial culture and fruiting body productivity were investigated in a new Lentinula edodes cultivar, “Jadam”, in sawdust medium for the stable production of oak mushroom. As the punching volume and number increased, the weight loss rate and color difference increased and the L value decreased. After spawn inoculation, the sawdust medium temperature and CO2 concentration reached their highest values at 33 and 19 days of incubation, respectively. The O2 concentration showed the lowest value on the 14th day of incubation, which was the opposite pattern to the CO2 concentration. As the punching volume and the number increased, the medium temperature and O2 concentration increased, and the CO2 concentration decreased. Higher punching volumes and numbers resulted in higher temperatures and lower CO2 concentrations. The best fruiting body yield was 5 × 70 mm - 30 (punching diameter × depth - number), and the total yield after three cycles was 644.7 g.

A new spore-less cultivar Lentinula edodes ‘Daedam’ was bred from monokaryotic strains of ‘LE15401-24’ and ‘LE192118-10’. The optimum temperature for mycelial growth of ‘Daedam’ on potato dextrose agar was 22~25oC. Total cultivation period of the new cultivar, from inoculation to its first harvest, was 134 days, similar to that of the control cultivar ‘Hwadam’. Total yield of ‘Daedam’ was 222g per 3kg substrate, and was lower than that of control cultivar(266.0g). The fruiting body of ‘Daedam’ had a thick and small pileus and a longer stem compare to control cultivar. As a result of a analyzing the productivity of ‘Daedam’ on the different substrate types, the biological efficiency was 26.7% in the 1.2kg cylindrical substrate(CS), which was higher than that of the 3kg rod-type substrate(RS). 'Daedam' had a similar yield compared to 'Hanacham' in first fruiting body production, but the cultivation period was 40 days shorter. Therefore, 'Daedam' can only harvest fruiting bodies once, it is thought that it can be used as spore-less oak mushroom cultivar for short-term cultivation instead of 'Hanacham' in mushroom farms.

This study was conducted to reduce the phenomenon of the biased cultivation of certain mushroom varieties and to develop a competitive variety of Pleurotus nebrodensis. We have collected and tested characteristics of genetic resources from domestic and overseas varieties since 2015. We bred the domestic variety ‘Boram’. The optimal temperature was 26~29oC for mycelial growth and 15~18oC for fruit body growth temperature. This variety was similar to the control variety (Uram) in terms of the number of cultivation days and yield per bottle. The shape of the new cultivar was round, whereas that of the control group was spatula-like. The yield was 181.1 g/bottle, which was statistically similar to that of the control variety. When incubating the parent and control varieties, the replacement line was clear. Moreover, polymerase chain reaction analysis of mycelial DNA resulted in different band patterns between the parent and control varieties, confirming the hybrid species.

Light plays an important role in fruit-body development and morphology during Pleurotus spp. cultivation. To understand the effects of light color on fruit-body properties, we evaluated the fruit-body characteristics of Pleurotus spp. varieties cultivated under blue, red, and purple LED light sources. The main results are as follows: The overall fruit-body shape showed differences depending on the color of the LED light. The fruit-bodies of mushroom cultivated under blue and purple light were generally similar to the mushroom shapes typically produced, while those of mushroom cultivated under green light were abnormally shaped, probably due to the absence of effective light source. The average cap lightness of mushrooms cultivated under blue, green, and purple LED lights was 57.0, 57.4, and 59.4, respectively. The average cap lightness of all varieties except Wonhyeong1ho and Hwang-geumsantari cultivated under the three LED light sources were statistically significantly different (P<0.05). The cap redness varied significantly depending on the LED lighting and variety. Only Gonji7hoM, the cap color mutant of Gonji7ho, showed negative cap redness values under all three LED light sources. Among the eight varieties excluding Gonji7ho, the highest cap redness was observed when cultivated under the blue LED. The average harvest weight of the varieties cultivated under purple, blue, and green LED light were 68.0, 58.3, and 50.1 g, respectively. The yield of Gonji7ho, the mushroom variety with the highest yield, cultivated under blue, green, and purple LED light were 92.8, 77.1, and 98.6 g, respectively. The earliness when grown under the purple, blue, and green LED lights were 5.3, 5.8, and 5.8 days, respectively. Among the varieties, six, three, and two cultivars showed the shortest earliness under the purple, green, and blue LED, respectively. The fruit-body lengths were 66.4, 51.8, and 46.8 mm when cultivated under green, purple, and blue lights, respectively. These results are expected to serve as a foundation for producing mushrooms with traits demanded in the market.

The oyster mushroom is a widely cultivated edible mushroom in Korea. It is a regionally specialized crop in Gyeonggi-do, where 68% of the national production is produced. The present study was conducted to develop a new, highquality cultivar with stable cultivation. ‘Manseon’ is a new variety of oyster mushroom suitable for bottle culture. It was produced by mating monokaryons isolated from ‘HB-18’ and ‘P15159-16’. The optimal temperature for ‘Manseon’ mycelial growth was 26–29 °C on potato dextrose agar (PDA) medium and for primordia formation and the growth of fruit bodies the optimal temperature was 18–19 °C on sawdust medium. Spawn running required 30 d, primordia formation required 4 d, and fruit body growth in the bottle culture required 4 d. Regarding the characteristics of the fruit bodies, the pilei were round and dark grayish brown, stipe color was white, and stipe shape was short and thick. The yield per bottle was 192.7 g/1,100 cc, which was 9% higher than that of the control strain (Suhan-1ho). The physical properties of springiness, cohesiveness, gumminess, and brittleness of stipe tissue were 87.9%, 77.4%, 445.1 kgf, and 389.6 kgf, respectively.

A fixed-point iteration is proposed to integrate the stress and state variables in the incremental analysis of plastic deformation. The Conventional Newton–Raphson method requires a second-order derivative of the yield function to generate a complicated code, and the convergence cannot be guaranteed beforehand. The proposed fixed-point iteration does not require a second-order derivative of the yield function, and convergence is ensured for a given strain increment. The fixed-point iteration is easier to implement, and the computational time is shortened compared with the Newton–Raphson method. The plane-stress condition is considered for the biaxial loading conditions to confirm the convergence of the fixed-point iteration. 3-dimensional tensile specimen is considered to compare the computational times in the ABAQUS/explicit finite element analysis.

The present study investigated the optimum additive ratio of wheat straw pellet as a substitute for beet pulp during oyster mushroom cultivation. The chemical properties across treatments were pH of 4.8–5.5, total carbon content of 45.9–46.5%, total nitrogen content of 1.5–1.7%, and carbon-to-nitrogen ratio of 27.8–31.0. Mycelial growth was the fastest in a medium containing 20% wheat straw pellet (at 88.2 mm in ‘Heuktari’ and 70.3–79.6 mm in ‘Suhan-1Ho’); however, there were no significant differences in mycelial density among the treatments. The characteristics of fruiting bodies by variety were as follows. In ‘Heuktari’, the valid stipe number per bottle (1,100 cc) was 22.5 and yield was 177.1 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls. In ‘Suhan-1Ho’, the valid stipe number per bottle (1,100 cc) was 14.0 and yield was 151.2 g/1,100 cc in the mixed medium containing 10% wheat straw pellet, with the values being comparable to those of controls.

Mushroom production in Korea is concentrated on five major mushroom types. To create a new source of income for farmers, it is necessary to establish new mushroom production and marketing systems. This study was conducted to evaluate the marketability of and establish a marketing strategy for Pleurotus nebrodensis variety 'Uram'. The evaluation of distributors showed that it was necessary to cultivate mushrooms of uniform shape and size, to compensate for their low storability, and to sell them in small packages. The consumer evaluation showed that the texture of P. nebrodensis had the highest level of satisfaction for quality, but the levels of satisfaction for size and shape were low. In the consumer evaluation, as in the distributor evaluation, improvements in cultivation were found to be necessary, as the storage time is short due to a high moisture content. An evaluation of the market gave the following results regarding the marketing strategy. It was found to be necessary to consider the production of mushrooms of a uniform shape and size and sell them in small packages in the range of 150 to 300 g. The price of the mushrooms should be set using a high-end strategy for high-end sales. The mushrooms should be introduced to local food and eco-friendly stores in the early stages of production. Subsequently, if farmhouse production increases, shipments should be made to wholesale markets through a regular contract. Finally, considering that P. nebrodensis is an unfamiliar mushroom to consumers, it is necessary to promote it by increasing the accessibility of consumers through tasting events and experience groups.

This study was conducted to investigate the optimum supplementation ratio when replacing cotton seed meal with rapeseed meal for cultivating oyster mushrooms. The chemical properties among the treatments were pH 4.5~4.7, total carbon content was 46.3~46.5%, total nitrogen content was 1.6~1.7%, and carbon-nitrogen ratio was 27.0~27.8. These did not differ significantly from the control. Mycelial growth was 85.1 mm (Heuktari), and 72.8 mm (Suhan-1Ho) in medium containing 5% rapeseed meal, with no significant difference in mycelial density between cultivars. Fruiting body characteristics are as follows: In 'Heuktari', the color of the pileus was darker than control with an L value of 32.5, and pileus thickness and diameter were 3.2 mm and 27.6 mm, respectively. Stipe length and diameter were 86.0 mm and 9.1 mm, respectively. Valid stipe number per bottle (1,100 cc) was 25.9, and a yield of 189.7 g/1,100 cc was recorded in mixed medium containing 5% rapeseed meal (higher than control). In mixed medium containing 10% rapeseed meal, the yield was 184.5 g/1,100 cc (comparable to control). In 'Suhan-1Ho', supplemented with 5% rapeseed meal, pileus color was darker than control color, with an L value of 28.8. Pileus thickness was 4.5 mm. Stipe diameter was 12.3 mm (higher than control), and yield was 145.5 g/1,100 cc (comparable to control).

This study was conducted to diversify the cultivation of mushroom items and develop a competitive variety of Hypsizigus marmoreus. We focused on developing Hypsizigus marmoreus with lower bitterness, likable shape, and high yield. We have collected and tested characteristics of genetic resources from domestic and abroad since 2019. Breeding (2019), characterization (2020), productivity test (2021), and farm demonstration test (2021) have been sequentially conducted. We bred the new variety ‘Yunseul’ with unique traits. The optimal temperature for mycelial and fruit body growth were 22–25oC and 15– 18oC, respectively. It was similar to the control variety (Mangadak-2Ho) in the pileus form (hemispherical shape) and the cultivation period. However, it was thinner and longer than the control variety with the pileus diameter, thickness, stipe diameter, and length being 19.9 mm, 7.0 mm, 9.4 mm, and 86.3 mm, respectively. The effective number of fruit bodies was 47.8 in bottle cultivation, which was more than that of the control variety. The yield was 197.4 g/bottle (1,100 cc), which was 30% higher than the yield of the control variety, 151.9 g/bottle (1,100 cc). The parent and control varieties were also incubated alongside the new variety. The somatic incompatibility line was distinct. The band pattern in the mycelial DNA PCR reaction was different from that of the parent and control varieties, confirming the hybrid species.

This study was conducted to reduce the phenomenon of biased cultivation and to pursue the diversification of mushroom items. We focused on developing Sparassis latifolia varieties with a short cultivation period, stable pinheading, and a high yield. We have collected and determined the characteristics of genetic resources domestically and abroad since 2016. We bred the unique domestic variety, “Hanyeoul” and the results of this study are as follows. The optimal temperatures for mycelial growth and fruit body growth were 22~25oC and 19~21oC, respectively. The color of the pileus was pale-yellowish white, which was similar to the color of the control variety, “Neoul”. The number of days required for cultivation was 125 for bottle cultivation and 98~102 for bag cultivation, which was shorter than the number of days required for the control variety. Bottle cultivation took 39 days shorter for the new variety than the control variety. The fruiting body of the new variety was similar in size or larger than that of the control variety. The pinheading rate was more than 90% in bottle cultivation and bag cultivation, which was more stable than pinheading in the control variety. The yield was 79.1 g/bottle (1,100 cc) for bottle cultivation, which was 22.6% higher than the yield of the control variety, and 641.1~689.5 g/bag (2.6 kg) for bag cultivation, which 5.8~10.4% higher than yield of the control variety.

The effect of the laser beam diameter on the microstructure and hardness of 17-4 PH stainless steel manufactured via the directed energy deposition process is investigated. The pore size and area fraction are much lower using a laser beam diameter of 1.0 mm compared with those observed using a laser beam diameter of 1.8 mm. Additionally, using a relatively larger beam diameter results in pores in the form of incomplete melting. Martensite and retained austenite are observed under both conditions. A smaller width of the weld track and overlapping area are observed in the sample fabricated with a 1.0 mm beam diameter. This difference appears to be mainly caused by the energy density based on the variation in the beam diameter. The sample prepared with a beam diameter of 1.0 mm had a higher hardness near the substrate than that prepared with a 1.8 mm beam diameter, which may be influenced by the degree of melt mixing between the 17-4 PH metal powder and carbon steel substrate.

In this study, additive manufacturing of a functionally graded material (FGM) as an alternative to joining dissimilar metals is investigated using directed energy deposition (DED). FGM consists of five different layers, which are mixtures of austenitic stainless steel (type 316 L) and low-alloy steel (LAS, ferritic steel) at ratios of 100:0 (A layer), 75:25 (B layer), 50:50 (C layer), 25:75 (D layer), and 0:100 (E layer), respectively, in each deposition layer. The FGM samples are successfully fabricated without cracks or delamination using the DED method, and specimens are characterized using optical and scanning electron microscopy to monitor their microstructures. In layers C and D of the sample, the tensile strength is determined to be very high owing to the formation of ferrite and martensite structures. However, the elongation is high in layers A and B, which contain a large fraction of austenite.

The plastic deformation behavior of additively manufactured anisotropic structures are analyzed using the finite element method (FEM). Hill’s quadratic anisotropic yield function is used, and a modified return-mapping method based on dual potential is presented. The plane stress biaxial loading condition is considered to investigate the number of iterations required for the convergence of the Newton-Raphson method during plastic deformation analysis. In this study, incompressible plastic deformation is considered, and the associated flow rule is assumed. The modified returnmapping method is implemented using the ABAQUS UMAT subroutine and effective in reducing the number of iterations in the Newton-Raphson method. The anisotropic tensile behavior is computed using the 3-dimensional FEM for two tensile specimens manufactured along orthogonal additive directions.

This study was conducted to establish an appropriate period of use of sawdust spawn at low temperatures and a nutrient supplement medium for cultivation of Lentinula edodes ‘Hwadam’. Of the nutrient supplements, the total yield of rice bran (5%) + corn flour (5%) treatments were 673.3 g, which was higher than rice bran (551.6 g) and wheat bran (546.7 g) treatments, respectively. As shown by the growth of Lentinula edodes ‘hwadam' during to the sawdust spawn storage period (at 4oC), the period of spawn running, browning, fruiting body formation, and development was 27 d, 81 d, 5 d, and 11-13 d, respectively, regardless of the length of the storage period at 4 oC. After 3 months of storage of sawdust spawn, the number of fruiting bodies and yield decreased as the storage period increased. Therefore, the period of use of sawdust spawn (at 4 oC) for the stable production of fruiting bodies of Lentinula edodes ‘Hwadam’ was a maximum of 3 months.

This study was conducted to reduce the phenomenon of the biased cultivation of certain mushroom varieties and to develop a competitive variety of Grifola frondosa. We developed the first Korean white commercial mushroom strain, ‘Bakyeon’, by crossing monokaryons derived from brown strains. We have collected and tested the characteristics of mushrooms from domestic and international genetic resources since 2018. We bred the unique domestic variety, ‘Bakyeon’, which has the following characteristics. The optimal temperature for mycelial growth was 25~28oC and the optimal temperature for fruit body growth was 16~18oC. The new variety was similar to the control variety (Daebak) in terms of the pileus, which formed a pine cone shape, and the number of days of cultivation. The yield was 94.1 g/bottle, which was 23% lower than the 108.5 g/bottle yield of the control variety. When incubating the parent and control varieties, the replacement line was clear. Moreover, polymerase chain reaction analysis of mycelial DNA resulted in different band patterns between the parent and control varieties, confirming the hybrid species.

In this study, we have prepared a Ti-6Al-4V/V/17-4 PH composite structure via a direct energy deposition process, and analyzed the interfaces using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The joint interfaces comprise two zones, one being a mixed zone in which V and 17-4PH are partially mixed and another being a fusion zone in the 17-4PH region which consists of Fe+FeV. It is observed that the power of the laser used in the deposition process affects the thickness of the mixed zone. When a 210 W laser is used, the thickness of the mixed zone is wider than that obtained using a 150 W laser, and the interface resembles a serrated shape. Moreover, irrespective of the laser power used, the expected  phase is found to be absent in the V/17-4 PH stainless steel joint; however, many VN precipitates are observed.

In order to evaluate the earthquake safety of equipment in structures, it is essential to analyze the In-Structure Response Spectrum (ISRS). The ISRS has a peak value at the frequency corresponding to the structural vibration mode, but the frequency and amplitude at the peak can vary because of many uncertain parameters. There are several seismic design criteria for ISRS peak-broadening for fixed base structures. However, there are no suggested criteria for constructing the design ISRS of seismically isolated structures. The ISRS of isolated structures may change due to the major uncertainty parameter of the isolator, which is the shear stiffness of the isolator and the several uncertainty parameters caused by the nonlinear behavior of isolators. This study evaluated the effects on the ISRS due to the initial stiffness of the bi-linear curve of isolators and the variation of effective stiffness by the input ground motion intensity and intense motion duration. Analyzing a simplified structural model for isolated base structure confirmed that the ISRS at the frequency of structural mode was amplified and shifted. It was found that the uncertainty of the initial stiffness of isolators significantly affects the shape of ISRS. The variation caused by the intensity and duration of input ground motions was also evaluated. These results suggested several considerations for generating ISRS for seismically isolated structures.