PURPOSES : In this study, we evaluated the quality levels of abrasion resistance and freeze-thaw resistance to the surface layer (colored layer) by using an overseas abrasion resistance test method to confirm the quality suitability of the concrete block surface for a domestic production permeable block. METHODS : In this study, a new evaluation item for increased durability apart from the quality standard of the permeable block was considered, namely, evaluation of the durability of the surface layer and the freeze-thaw resistance of the permeable block itself by EN 1338, ASTM C 779, 994, and GR 4009 (KS F 4419). RESULTS : The abrasion resistance test for the permeable block revealed that there were relative differences according to the different test methods. However, it was observed that if the ASTM C 779 test results did not meet the wear resistance quality standards, it did not satisfy ASTM C 944 and EN 1338. The ASTM C 779 test result was analyzed to have the highest objectivity and discernment, and this test method was proposed as a permeable block wear test method. In addition, the freeze-thaw resistance test method by the GR 4007 standard can be measured by strength, so it is possible to evaluate the resistance of the permeable block through this test method. CONCLUSIONS : The abrasion resistance test and freeze-thaw resistance test can contribute to the improvement of the permeable block when added to the current quality evaluation tests.

PURPOSES : This study was conducted to analyze the problems of the permeable block by objectively evaluating the quality of the permeable block and providing basic data to improve the quality and construction defect of the permeable block pavement in accordance with the continuously increasing demand of the permeable block. METHODS : In this study, we evaluated the current quality standard suitability of nine products to evaluate the current quality level of domestic production permeable blocks. The evaluation items were evaluated for surface layer thickness, block dimension, strength, and permeability coefficient, and the Korea Standard suitability for these evaluation items was analyzed. In addition, a three-dimensional finite element analysis was conducted to determine the effect of vehicle load on the deformation of block pavement structure. RESULTS : The results demonstrated that the surface layer (colored layer) thicknesses of domestically produced permeable block products were different according to the quality standards, and the dimensions were evaluated to be excellent for domestic permeable blocks currently being produced and delivered. In addition, the strength and permeability coefficient evaluation result demonstrated that all products meet the strength and permeability coefficient quality standards, but the correlation between these strengths and permeability coefficients is not high. The quality standard of strength and permeability coefficients is evaluated as being sufficiently achieved by domestic production technology. CONCLUSIONS: The intensity and permeability coefficients measured in this study were in line with the quality standards; however, the variable coefficient was found to have a significant difference in the quality control level from a maximum of 26% to a minimum 1.7%.

PURPOSES : In this study, a numerical clogging model that can be used to realistically visualize the movement of particles in cylindrical permeability test equipment was proposed based on the system coupling of computational fluid dynamics with the discrete element method and experimental permeability test results. This model can also be used to simulate the interaction of dust particles with bedding particles. METHODS: A 4-way system coupling method with multiphase volumes of the fluid model and porous media model was proposed. The proposed model needs to consider the influence of flow on the dust particles, interaction between the dust particles, and interaction between the dust particles and bedding layer particles. The permeability coefficient of the bedding layer in cylindrical permeability test equipment was not calculated by using the permeability test result, but was estimated by using the particle packing model and Ergun model. RESULTS : The numerical simulation demonstrated a good agreement with the experimental test results in terms of permeability and drain time. Additionally, the initial movement of particles due to the sudden drain hole opening was successfully captured by the numerical model. CONCLUSIONS : A 4-way coupling model was sufficient to simulate the water flow and particle movement in cylindrical permeability test equipment. However, additional tests and simulation are required to utilize the model for more realistic block pavement systems.

PURPOSES : In this study, a series of fundamental falling head permeability tests were conducted on a binary particle mix bedding to determine the minimum water level, bedding layer thickness, and amount of dust that can result in the stable permeability with high repeatability. The determined condition is used to develop a CFD-DEM coupled clogging model that can explain the movement of dust particles in flowing water of a block pavement system. METHODS: A binary particle mixture is utilized to experimentally simulate an ideal bedding layer of a block pavement system. To obtain a bedding layer with maximum packing degree, the well-known particle packing degree model, i.e., the modified Toufar model, was utilized. The permeability of the bedding layer for various water levels, bedding layer thicknesses, and amounts of dust was calculated. The permeability for a small water level drop was also plotted to evaluate the effect of dust on the bedding layer clogging. RESULTS: It was observed that a water level of 100 mm, bedding depth of 70 mm, and dust amount of 0.3 g result in a stable permeability condition with high repeatability. The relationship between the minimum dust amount and surface clogging of the bedding layer was suggested based on the evaluation of the volumetric calculation of the particle and void and the permeability change in the test. CONCLUSIONS: The test procedure to determine the minimum water level, bedding thickness, and dust amount was successfully proposed. The mechanism of clogging on the surface of the bedding layer was examined by relating the volumetric characteristics of dust to the clogging surface.

There are lots of duplicative components in the glyph blocks of Maya hieroglyphs. Some of them are used to double the meaning or sound value of the original components. Some of them are just the aesthetic consideration of scribal which does not affect the significance of the original components. This phenomenon, which was discovered by earlier Maya epigraphers, still needs researches on its causes and substitution patterns. This essay discussed these two issues based on the rearrangement of the glyph blocks containing duplicative components. From the perspective of graphic structure, the doubling phenomenon existed in both syllabic signs and glyphs. There are two reasons for the doubling phenomenon as such. The redundancy and simplification of signs lead to the sign-internal duplication. The unique spelling rule of Mayan language lead to the repetition of the syllabic signs. From the perspective of glyphs, the doubling phenomenon existed in both compound graphs and couplets which are caused by the recombination of glyphs. The substitution patterns of these phenomenon are the use of doubling signs, underspelling, choosing different variants of the same syllabic sign, and sharing components. All of these four substitution patterns can function both in the glyph-internal and between different glyphs.

PURPOSES : The purpose of this study is to evaluate the performance of road stone block pavements using APT (Accelerated Pavement Testing), which can evaluate the short-term pavement performance of a pavement structure for a given traffic load. METHODS : The performance of stone block, concrete block, and asphalt (modified SMA) pavements were evaluated according to the cumulative equivalent load by using APT. The FWD (Falling Weight Deflectometer) test was used to analyze the deflection per unit load. In addition, the plastic settlement was analyzed by transverse profile measurement. RESULTS: The results of the APT of about 197,000 ESALs (Equivalent Single Axle Loads) show that there were no damages in the stone block, concrete block, and asphalt pavement, such as breakage of stone or concrete block, cracking of asphalt, deflection, and plastic settlement of the wheel-pass section. It was analyzed that the bearing capacity of each pavement section did not decrease sharply with increase in cumulative ESAL. The results of plastic settlement analysis show that in the case of asphalt pavement, the plastic settlement steadily progressed from the beginning of the APT, and a settlement of about 4.76 mm occurred. In the case of concrete block and stone block pavements, no significant change occurred after the initial stabilization step, and plastic settlement of about 1.01 mm and 0.17 mm occurred for the concrete block and stone block pavements, respectively. CONCLUSIONS : As a result of the analysis of the bearing capacity and plastic settlement after the APT, the performance of stone pavement was found to be similar to that of asphalt pavement and concrete block pavement. Therefore, it is concluded that stone pavements are applicable for the road pavement system.

Poly(ether block amide) (PEBA)는 이산화탄소 분리에 매우 적합한 상용 블록 공중합체 중 하나이다. 기체분리막의 경우 높은 투과도 뿐 아니라 강한 기계적 강도 또한 필요로 한다. PEBA공중합체의 결정성 폴리아마이드(polyamide) 블록은 기계적 강도를 제공하며 동시에 rubbery한 폴리에테르(polyether) 부분은 이산화탄소와의 친화도를 부여하여 이산화탄소 촉진 수송에 기여한다. PEBA공중합체에서 결정성 상과 rubber한 상의 조성은 기체분리막에 적합하게 조절될 수 있다. PEBA 공중합체를 기반으로 한 분리막은 좋은 투과도를 갖지만 추가적으로 분자체 효과를 이용하여 큰 기체 투과도 손실 없이 분리막의 선택도를 향상시킬 수 있다. 혼합 매질 분리막은 혼합막의 한 종류로서 고분자 매트릭스와 유기 첨가제로 이루어져 있다. 하지만 고분자 매트릭스와 유기 첨가제간의 양립성(compatibility)에 따른 문제점 또한 존재한다. 따라서 본 총설에서는 PEBA 공중합체를 기반으로 한 혼합막의 장점과 한계에 대해 다루고자 한다.

Recent earthquakes in Korea caused some damages to stone pagodas and thereby awakened the importance of earthquake preparedness. Korean stone pagodas which have been built with very creative style of material use and construction method are worthy of world heritage. Each stone pagoda consists of three parts: top; body; and base. However each tower is uniquely defined by its own features, which makes it more difficult to generalize the seismic assessment method for stone pagodas. This study has focused on qualitative preliminary evaluation of stone pagodas that enables us to compare the relative seismic performance across major aspects among many various Korean pagodas. Specifically an analytical model for multi-block stone pagodas is to be proposed upon the investigation of structural characteristics of stone pagoda and their dynamic behavior. A strategy for seismic evaluation of heritage stone pagodas is to be established and major evaluation factors appropriate for the qualitative evaluation are identified. The evaluation factors for overall seismic resisting behavior of stone pagodas are selected based on the dynamic motions of a rigid block and its limit state. Numerical simulation analysis using discrete element method is performed to analyze the sensitivity of each factor to earthquake and discuss some effects on seismic performance.

Coke aggregates and carbon artifacts were produced to investigate the interactions of coke and pitch during the kneading process. In addition, the kneading ratio of the coke and binder pitch for the coke aggregates was controlled to identify the formation of voids and pores during carbonization at 900°C. Experiments and thermogravimetric analysis revealed that carbon yields were improved over the theoretical yield calculated by the weight loss of the coke and binder pitch; the improvement was due to the binding interactions between the coke particles and binder pitch by the kneading process. The true, apparent, and bulk densities fluctuated according to the kneading ratio. This study confirmed that an excessive or insufficient kneading ratio decreases the density with degradation of the packing characteristics. The porosity analysis indicated that formation of voids and pores by the binder pitch increased the porosity after carbonization. Image analysis confirmed that the kneading ratio affected the formation of the coke domains and the voids and pores, which revealed the relations among the carbon yields, density, and porosity.

This paper develops a flow control block for a hydraulic system of a tunnel boring machine. The flow control block is a necessary component to ensure stability in the operation of the hydraulic system. In order to know the pressure distribution of the flow control block, the flow analysis was performed using the ANSYS-CFX. It was confirmed that the pressure and flow rate were normally supplied to the hydraulic system even if one of the four ports of the flow control block was not operated. In order to evaluate the structural stability of the flow control block, structural analysis was performed using the ANSYS WORKBENCH. As a result, the safety factor of the flow control block is 1.54 and the structural stability is secured.

An organic filler, bis-(N-α-amido-3,4-dihydroxyphenylalanine)-1,7-heptane dicarboxylate (DOPA-C7) is applied to gas separation membranes for CO2/N2 separation. The weak interaction between SBS and DOPA-C7 improves CO2/N2 selectivity, from 14.1 to 21.1 with increasing of CO2 permeability from 347.5 to 349.7 Barrer. This phenomenon is caused by the catechol group of DOPA-C7 that can work as a Lewis Base. However, the strongly interacting PEBAX/DOPA-C7 membranes show a typical trade-off behavior, a decrease in CO2 permeability and increase in CO2/N2 selectivity with the filler contents. This results demonstrate that interactions between the filler and polymeric matrix can cause negative effects on the gas separation performance. This work opens up the feasibility of using a catecholic compound in gas separation membranes.

In this paper, we study the existing results of the structure-soil-structure interaction (SSSI) effect on seismic responses of structures and summarize important parameters. The parameters considered in this study are a combination of buildings in the power block of a nuclear power plant, the characteristics of earthquake ground motions and its direction, and the characteristics embedded under the ground. Based on these parameters, the seismic analysis model of the structures in the power block of the nuclear power plant is developed and the structure-soil-structure interaction analyses are performed to analyze the influence of the parameters on the seismic response. For all analyses, the soil-structure interaction (SSI) analysis program CNU-KIESSI, which was developed to enable large-sized seismic analysis, is used. In addition, the SSI analyses is performed on individual structures and the results are compared with the SSSI analysis results. Finally, the influence of the parameters on the seismic response of the structure due to the SSSI effect is reviewed through comparison of the analysis results.

This study suggests a model of production information system that can reduce manufacturing lead time and uniformize quality by using DNC S/W as a part of constructing production information management system in the industrial field of the existing marine engine block manufacturing companies. Under the effect of development of this system, the NC machine interface device can be installed in the control computer to obtain the quality information of the workpiece in real time so that the time to inspect the process quality and verify the product defect information can be reduced by more than 70%. In addition, the reliability of quality information has been improved and the external credibility has been improved. It took 30 minutes for operator to obtain, analyze and manage the quality information when the existing USB memory is used, but the communication between the NC controller computer and the NC controller in real time was completed to analyze the workpiece within 10 seconds.

Digital advertising is one of the most crucial medium of communication and marketing (Berner and Kiley, 2005). Digital advertising brings with itself several benefits such as increase in reach, low advertising cost, and high degree of customer engagement. However, along with benefits it also brings several challenges for the marketers such as comprehending consumer attitude, consumption and behaviour towards digital advertisements. According to prior literature attitude towards internet consists of factors such as information, entertainment, irritation, and trustworthiness (Aaker & Bruzzone, 1985). Ad blocking has become one of the most important concerns for advertising industry globally. This paper has attempted to understand the series of actions that leads to ad blocking. This series consists of consumer response and consumer attitude towards digital advertising where the constant ad delivery creates ad intrusiveness which leads to ad irritation which in turn leads to ad avoidance and ultimately results in ad blocking. Ad blocking further has serious consequences in brand image and brand valuation, because as more number of users opt to download and use ad blockers, advertisement instead of increasing brand valuation results in brand devaluation, not to mention wastage of ad spend. Through literature review it was found that reports discuss ad blockers and its operations but there is little understanding on the process that leads a consumer to install ad blocking software on his digital device. The research objective of the study is therefore, to understand cognitive process of consumers that leads them to take a decision of installing an ad blocking software on their digital device. The study therefore proposes four research questions, 1. What aspects of online advertising irritate users? 2. How do consumers avoid advertisements? 3. What causes a consumer to use ad blocker? 4. What cognitive process lead a consumer to install ad blocking software? A mixed method research is adopted for the purpose of this paper. In the first stage a qualitative research was conducted through semi-structured interviews in order to understand consumer opinion on what leads them to install an ad blocking (Jagani and Panda 2016). Thematic analysis of transcripts was conducted from which 81 items on ad irritation, ad avoidance and ad blocking were identified for second stage of the study which consists of online survey using quantitative research methods. The items for the quantitative survey are \categorised in three main categories viz. Irritation, Avoidance and Action. The sample consists of 18 to 35 year olds who are active users of internet and have been exposed to digital advertisement, spends more than two hours per day on internet through various digital device and are aware of ad blockers or have used them in the past. Non-probabilistic sampling method was selected for the study and quota sampling was implemented. The study aims to comprehend the process that leads a consumer to install an ad blocking software on his or her digital device.

Well-defined methacrylate based amphiphilic block copolymers (BCs) used as additives to fabricate poly(vinylidene fluoride) (PVDF) UF membranes, where the amphiphilic BC additives hydrophilically altered PVDF with PPEGMA block segment by strong interaction with the other PMMA block segment, which reduced water resistance to the PVDF polymer solution during phase separation. FT-IR and XPS studies showed carbonyl groups of BCs in the PVDF membranes. Obtained membranes showed porous surface layer and finger-like pore structures on the sublayers, of which sizes were increased with the increase of BC contents. Obtained membranes showed MWCO with 100K PEO and the best water flux was achieved in the PVDF membrane with BC/LiCl additive and improved the anti-fouling property for BSA protein.

There is a great importance in the development of anion exchange membrane fuel cells (AEMFCs) for renewable energy research. The high conductivity and alkaline stability under high pH conditions at elevated temperatures are required for AEMs. We report herein SEBS-based AEMS with different hydrophobic side chain lengths, and investigated the properties of the corresponding AEMs, including conductivity, morphology and chemophysical stabilities.

Anion exchange membrane fuel cells (AEMFCs) have attracted a growing interest as an alternative for proton exchange membrane fuel cells (PEMFCs). AEMs are the most important components of AEMFCs, and it’s a great challenge to attain high ion conductivity, good dimensional, mechanical and alkaline stabilities for AEMs. We prepared poly(ether sulfone ketone)s having various hydrophilic-hydrophobic block ratios, and investigated the effect of the block composition on the chemo-physical properties of the corresponding membranes. The experimental procedures and the properties, including conductivity, morphology and stability will be discussed in detail.

Polymer membrane-based gas separation has been attracting recent interest due to its ease of operation and low operational cost. Polyimides (PIs) are the most widely used polymers for this application due to their toughness and moderate gas separation properties. However, the gas separation performance of the current polymers, including PIs, do not meet the requirement for the industrial applications. We report herein multi-block PIM-co-PIs as novel polymer membranes for CO2 separation. Synthesis, characterization and their properties including gas separation performance of various compositions of PIM-PI block copolymer membranes will be discussed in details.