• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.337-347
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• 2006

Papers made from unbleached and bleached bagasse chemimechanical pulp were chemically modified by acetylation. The effects of irradiation on unbleached and bleached also reduced papers of bagasse chemimechanical pulp before and after acetylation were investigated in this study. Chemimechanical pulp was prepared from bagasse and then bleached with hydrogen peroxide. Unbleached and hydrogen bleached pulps were reduced by Sodium borohydride in different procedures. Paper sheets were prepared from pulps and then acetylated using a technical grade of acetic anhydride. Accelerated photo-aging was run on the samples using fluorescent lamps to verify photo-stability of paper sheets before and after pretreatments. Brightness reversion (as Post-color number) and other optical properties of the paper sheets were measured. Efficient inhibition of photo-yellowing of papers made from bagasse CMP was achieved by acetylation. The acetylated unbleached CMP was noticeably photo-bleached during irradiation. Sodium borohydride reduction followed by acetylation had the same effect as acetylation alone at the same degree of reaction time and reductive treatment did not affect the yellowing rate to any great extent. The pre-reduced, acetylated unbleached papers were, however, not brightened during irradiation. Calculation done by Kubelka-Munk equation showed that reductive treatment had little effect in reducing the photo-yellowing of paper made from CMP pulp; a small stabilization effect was observed in the case of bleached CMP, while unbleached CMP was slightly more prone to discolor in the later phase of photo-reversion. The improved stability towards light may was closely related to the decrease in the phenolic hydroxyl content as a result of blocking by acetyl groups during treatment with acetic anhydride. The results support the hypothesis that phenolic hydroxyl has an important role in the process of photo-reversion of high-yield pulps. The results obtained in this study demonstrate that the acetylation of paper manufactured from peroxide bleached Bagasse CMP significantly retards light-induced discoloration. The inhibition of yellowing is connected with a decrease in the phenolic hydroxyl content of both unbleached and peroxide bleached papers.

• Advances in nano research
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• v.16 no.6
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• pp.623-638
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• 2024

This study investigates the thermal post-buckling behavior of concrete eccentric annular sector plates reinforced with graphene oxide powders (GOPs). Employing the minimum total potential energy principle, the plates' stability and response under thermal loads are analyzed. The Haber-Schaim foundation model is utilized to account for the support conditions, while the transform differential quadrature method (TDQM) is applied to solve the governing differential equations efficiently. The integration of GOPs significantly enhances the mechanical properties and stability of the plates, making them suitable for advanced engineering applications. Numerical results demonstrate the critical thermal loads and post-buckling paths, providing valuable insights into the design and optimization of such reinforced structures. This study presents a machine learning algorithm designed to predict complex engineering phenomena using datasets derived from presented mathematical modeling. By leveraging advanced data analytics and machine learning techniques, the algorithm effectively captures and learns intricate patterns from the mathematical models, providing accurate and efficient predictions. The methodology involves generating comprehensive datasets from mathematical simulations, which are then used to train the machine learning model. The trained model is capable of predicting various engineering outcomes, such as stress, strain, and thermal responses, with high precision. This approach significantly reduces the computational time and resources required for traditional simulations, enabling rapid and reliable analysis. This comprehensive approach offers a robust framework for predicting the thermal post-buckling behavior of reinforced concrete plates, contributing to the development of resilient and efficient structural components in civil engineering.

• Advances in nano research
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• v.17 no.4
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• pp.385-399
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• 2024

NEMS (Nano-Electro-Mechanical Systems) devices play a significant role in the advancement of prosthetic hands due to their unique properties at the nanoscale. Their integration enhances the functionality, sensitivity, and performance of prosthetic limbs. Understanding the electro-thermal buckling behavior of such structures is crucial since they may be subjected to extreme heat. So, in this paper, the two-dimensional hyperbolic differential quadrature method (2D-HDQM) integrated with a four-variable refined quasi-3D tangential shear deformation theory (RQ-3DTSDT) in view of the trace of thickness stretching is extended to study electro-thermal buckling response of three-directional poroelastic FG (3D-PFG) circular sector nanoplate patched with piezoelectric layer. Aimed at discovering the real governing equations, coupled equations with the aid of compatibility conditions are employed. Regarding modeling the size-impacts, nonlocal refined logarithmic strain gradient theory (NRLSGT) with two variables called nonlocal and length scale factors is examined. Numerical experimentation and comparison are used to indicate the precision and proficiency related to the created procedure. After obtaining the outputs of the mathematics, an appropriate dataset is used for testing, training and validating of the artificial intelligence. In the results section will be discussed the trace associated with multiple geometrical and physical factors on the electro-thermal buckling performance of the current nanostructure. These findings are essential for the design and optimization of NEMS applications in various fields, including sensing, actuation, and electronics, where thermal stability is paramount. The study's insights contribute to the development of more reliable and efficient NEMS devices, ensuring their robust performance under varying thermal conditions.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.85-90
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• 2006

Increasing the filler content of sheet improves the optical properties and printability of paper and provides an opportunity for saving production cost through fiber replacement with relatively low-priced filler. But increasing the filler content tends to decrease the strength of paper and filler retention. It also tends to deteriorate drainage on the paper machine. To overcome these problems, preflocculation technology of fillers may be employed. Many research efforts have been made on the properties of preflocculated filler, namely prefloc, whose size and size distribution were influenced by polymer type and shear level. But there is much to be investigated about the effect of the prefloc characteristics on the physical properties of paper. To evaluate the effect cationic polymers on the size and size distribution of preflocculated GCC and their shear stability, cationic PAM and cationic starch were used. The influence of the preflocculation on filler retention and its surface distribution, and the changes of physical and optical properties of handsheets affected by the characteristics of preflocs were examined. Filler distribution on sheet surface was also analyzed by EPMA. Results showed that cationic PAM formed large preflocs at low dosage. Cationic starch was required to add 15 times as much as cationic PAM to obtain the preflocs with similar size. But preflocs formed with cationic starch was superior in shear stability to those formed with cationic PAM. Filler preflocculation technology could provide an opportunity of increasing filler content significantly without loss in tensile strength. And increased filler contents could compensate brightness loss which often accompanies filler preflocculation. When excessively large preflocs were used, however, brightness loss rather than the improvement in tensile strength was predominant. Therefore it is of great importance to produce preflocs with proper size and shear stability for maximizing the improvement of physical properties of papers.

• Journal of Microbiology
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• v.44 no.4
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• pp.383-395
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• 2006

Four different Trichoderma strains, T. harzianum CECT 2413, T. asperellum T53, T. atroviride T11 and T. longibrachiatum T52, which represent three of the four sections contained in this genus, were transformed by two different techniques: a protocol based on the isolation of protoplasts and a protocol based on Agrobacterium-mediated transformation. Both methods were set up using hygromycin B or phleomycin resistance as the selection markers. Using these techniques, we obtained phenotypically stable transformants of these four different strains. The highest transformation efficiencies were obtained with the T. longibrachiatum T52 strain: 65-70 $transformants/{\mu}g$ DNA when transformed with the plasmid pAN7-1 (hygromycin B resistance) and 280 $transformants/l0^7$ spores when the Agrobacterium-mediated transformation was performed with the plasmid pUR5750 (hygromycin B resistance). Overall, the genetic analysis of the transform ants showed that some of the strains integrated and maintained the transforming DNA in their genome throughout the entire transformation and selection process. In other cases, the integrated DNA was lost.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.536-541
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• 1989

In present paper, we investigated the quality stability of frozen seasoned anchovy meat products during storage at $-25\;{\pm}\;2^{\circ}C$. The pH and VBN contents of the products revealed a tendency to increase slightly during frozen storage 150 days. Viable cell counts and histamine contents of products are $0.8-2.6\;{\times}\;10^5/g,\;70.6-76.7 mg/100g$, respectively. In changes of fatty acid composition, percentage of polyenes such as eicosapentaenoic docosahexaenoic acid slightly decreased, while that of saturates and monoenes increased during frozen storage, The results of changes in POV, TBA values, color values, drips and salt extractable nitrogen contents during frozen storage showed that lipid oxidation and freeze denaturation of products could be retarded, and flavor could be enhanced by adding 0.2% sodium erythorbate and 12.8% emulsion curd.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.67-78
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• 2008

The purpose of this paper is to discuss the design and implementation of a WCBT(Web and Computer based Test). The WCBT combines the strengths of both a WBT(Web-based test) and a CBT(Computer-based test) on the basis of efficiency and stability. The current assessment system, considered an important management tool in the construction and operation of a total management system for the national technical qualification, has some unstable elements with regard to system load and stability. The proposed system's technological aspects have been tested through a basic simulation pilot program. The pilot program will be expanded to include the local Chamber of Commerce and Industry because the stability of the system was proved through its application to the real-time national technical examination of KCCI (Korea Chamber of Commerce and Industry). The WCBT system has shown great efficiency in terms of system load, and has solved frequent communication problems which have occurred through the use of foreign qualifying examinations. The server and client systems of the WCBT have been given good evaluations with regard to the convenience of their use and the management system for operators and supervisors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1451-1456
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• 2020

Depending on the size and complexity of the game, interest in game quality control is increasing. The quality of the game can be evaluated through fun and stability tests, and the player's satisfaction varies greatly accordingly. For the quality control of the game, Fun QA is in charge of testing to increase the fun and give satisfaction to the players. In this study, we first looked at software quality improvement techniques and game QA work. And in order to improve game quality, we analyzed Fun QA, which is relatively unstructured compared to Technical QA, which is mainly responsible for stability testing. Based on this, the Fun QA process was proposed and an example of Fun QA design was presented using real games. It is expected that this study will be one of the pillars of the game quality management area pursuing quality improvement by guaranteeing fun. Furthermore, it is expected to help QA workers expand their work area.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.105-115
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• 2010

This technical paper describes and summarizes the flight test results for the longitudinal and lateal-directional dynamic stability characteristics. The target aircraft is the 4-seat carnard type aircraft, FireFly, which has been developed by KARI. Airborne sensors and real-time telemetry system are constructed to obtain the flight test data. The dynamic stability characteristics should be analyzed and tested by estimaitng the aerodynamic parameters in the dymaic equations of motion. The maximum likelihood estimation technique has been applied to the flight data from chirp, 3211, and doublet control inputs.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.178-178
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• 2008

In order to improve static stability and healing of reattached labrum, we combined the advantages of suture bridge and transosseous technique. Using the conventional 3 portal for anterior instability, check stability of bony Bankart and preparation of glenoid bed in 3 way including removal, reshaping or mobilization of bony fragment. Two anchors were inserted to the superior and inferior portion and medial edge of bony Bankart lesion. It usually corresponded to the area of IGHL. Medial mattress sutures were applied around IGHL complex to get enough depth of glenoid coverage using suture hook. Make 3.5mm pushlock anchor hole to the articular edge of glenoid cartilage. Proximal suture bridge was applied at first and then distal suture bridge was inserted to mobilize the labrum in proximal direction. These construction can provide more stable labral repair with wide contact and compression in case of deficient bony stability. It not only avoids technical disadvantage of point contact with anchor fixation, but also decreasing gap formation through cross compression of labrum that couldn't gain even with the transosseous fixation which affords linear compression effect. Additional bony stability could be gained if the the bony fragment was mobilized to the glenoid margin with potential healing bed or reshaped for the good contact with reattached labrum.