cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.12755/isec.res.2014.30
title: THE INFLUENCE OF INITIAL MATERIALS ON THE COMPRESSIVE STRENGTH OF GEOPOLYMER SOILS

description: In recent years, geopolymers have received significant attention because they show environmental benefits, such as a reduction in the consumption of natural resources and a decrease in the net production of CO2. In addition, as green material, soil has low carbon dioxide production emissions compared to other building materials. In this research, soil was combined with activator alkaline to produce hardening materials as geopolymer soils. An alkaline solution with sodium hydroxide, sodium silicate and fly ash was used. The influence of clay content on the geopolymer soils? compressive strength was investigated. The best strengths were obtained from 5% to 12% clay content. SEM photos were also taken from specimens to investigate the structure of geopolymer soils. When combined with soil and fly ash in geopolymerization, fly ash reacted to the alkali solution quickly. The relationships between many variables such as clay content, fly ash, alkaline solution, curing time, and curing temperature were investigated by using a statistical analysis program with over 100 initial parameters. These results also indicate that the use of soils in geopolymer soil should have been limited. Additionally, increasing the sodium silicate in the alkaline liquid affected the geopolymerization reaction significantly. However, the suitable Si on the alkaline solution and soil should be limited.
DOI: 10.12755/isec.res.2014.31
title: WIND TUNNEL TEST FOR CALCULATING WIND FORCES ON SCAFFOLDS WITH BASEBOARD HEIGHT AS A PARAMETER

description: The Japanese Industrial Safety and Health Law was revised in March 2009 to introduce new measures concerning accidental falls in the construction industry. This revision mandates the use of guard rails, handrails, and other scaffold components. The wind load criteria and structural specifications of scaffolds are regulated by current design codes. Nevertheless, these provisions do not necessarily comply with the newly incorporated legal requirements because they apply to old-style scaffolds. This study examined the wind force on scaffolds by wind tunnel test, with baseboard height used as a parameter. The wind force coefficient of one story of scaffolds was calculated. Wind force coefficient increased as baseboard height increased. The wind force on the scaffolds equipped with baseboards is 9.2 times that on the scaffolds without baseboards. The baseboard must be greater than or equal to 15 cm to satisfy regulation requirements. The wind force coefficient of scaffolds with a 15 cm baseboard is 1.5 times that of the scaffolds without a baseboard. In scaffold design, baseboard height should be considered to guarantee a suitable wind force coefficient.
DOI: 10.12755/isec.res.2014.32
title: PERMEABILITY OF TUNNEL LINING WITH AIR/WATER BUBBLES ON CONCRETE SURFACE

description: Air and water bubbles are likely to remain on concrete sidewalls in tunnel linings, because the sidewalls are generally constructed with a greater slope than a right angle. The bubbles negatively influence the aesthetic of the concrete lining. In addition, concrete with a lot of large bubbles may decrease durability, such as air permeability. Although most tunnel lining is constructed as plain concrete without reinforcement, the low permeability may affect the maintenance and long-term durability of the tunnel. The study aims to examine the effect of bubble distributions on the permeability of concrete lining. Concrete specimens including various bubble distributions are prepared by using variable angle-forms in a laboratory test. Furthermore, the bubble distribution (area ratio) and the permeability are examined in two actual tunnels. This paper presents a relationship between bubble distribution and air permeability based on these tests. The results show that the relationship is a logarithmic curve of the bubble rate and gas permeability.
DOI: 10.12755/isec.res.2014.33
title: DESIGN OF DOUBLE-SKINNED COMPOSITE TUBULAR OFFSHORE WIND TURBINE TOWERS

description: A double-skinned composite tubular (DSCT) offshore wind power tower was proposed and automatic section design software was developed. The developed software adopted a nonlinear material and nonlinear column model. As long as the outer diameter, material properties, and requested capacities are known for the DSCT wind power tower, the developed software can perform axial force-bending moment-interaction analyses for hundreds of sections of the tower, as well as suggest ten optimized cross-sectional designs. Assuming that the inner and outer tubes were made of steel, the software performed experimental design processes for a 5.0 MW and a 3.6 MW turbine. The software suggested rational and satisfactory section designs, and showed the possibility of a DSCT tower being used as an offshore wind power tower.
DOI: 10.12755/isec.res.2014.34
title: SEGMENT CRACKS AND ALIGNMENT ISSUES FOR TUNNELING CONSTRUCTION

description: This study describes the causes of shield tunnel segment cracks and alignment issues during shield tunnelling. The study was conducted in Down Town Line 3 (DTL3) contracts 926 and 927 twin tunnel projects in Singapore. It is revealed that these issues arose when Tunnel Boring Machine (TBM) shoving on curve alignment though TBM is designed with articulation, which allows the machines to handle tight curves with ease. The study focused on how construction methodology affects the quality of tunnelling in terms of alignment and segment cracks. It was found that the clearance between the tail shield and tunnel lining was not maintained during mining. As a result, the tail shield exerts stress on the segments and causes cracks. In addition, the tunnel alignment deviated from pre-designed alignment, which directly affects the safety and durability of the shield tunnel. This study concludes that a proper selection of ring type ?right lead? or ?left lead? and the appropriate key selection, along with the skill of the workers, significantly solve segment cracks and alignment issues.
DOI: 10.5281/zenodo.4911178
title: Quasi-BIC mode lasing in a quadrumer plasmonic lattice

description: Raw data used in Figures 1, 3, 4, and S4 in the manuscript. The experimental datasets are .csv and .spe files as read from the spectrometer and cameras used.
DOI: 10.5281/zenodo.4911177
title: Quasi-BIC mode lasing in a quadrumer plasmonic lattice

description: Raw data used in Figures 1, 3, 4, and S4 in the manuscript. The experimental datasets are .csv and .spe files as read from the spectrometer and cameras used.
DOI: 10.12755/isec.res.2014.35
title: DISPERSION OF WAVE FORCES ON CAISSON BREAKWATERS USING INTERLOCKING SYSTEMS

description: Interlocking caisson-type breakwaters have recently gained attention for enhancing the stability of the conventional breakwaters. In this study, the dispersion characteristics of wave forces using interlocking systems connecting the upper part of caissons with cables in the normal direction of breakwaters were investigated. Based upon numerical experiments, the higher wave forces are transmitted through the cable as the angle of incident wave increases, while the maximum allowable wave force was capable of being increased by sharing the wave forces with the adjacent caissons. It was also found that the larger the stiffness of the interlocking cable, the larger the wave-dispersion effect.
DOI: 10.12755/isec.res.2014.36
title: AN EXPERIMENTAL STUDY ON THE LOAD CAPACITY OF STEEL SCAFFOLDS WITH LINED SETUPS

description: Due to high clearances and large spans, some areas of reinforced concrete buildings, such as the entrance lobby of a hospital or the stage area of an auditorium, often need to design large-scale isolated reinforced concrete beams to support the weights from slabs and beams. On construction sites, the falsework of single-line steel scaffolds is often set up underneath these isolated beams based on the lined setup. Since the setup of these steel scaffolds is unique and data available for designing are lacking, single-line steel scaffolds are often installed on construction sites based on workers? experience. Study results show that the load capacities of one-bay, two-story door-type steel scaffolds (2D) are similar to those of one-bay, three-story door-type steel scaffolds (3D). When adopting multi-bay setups, the load capacities of two-story door-type steel scaffolds (2D) and of one-door, one-square, two-rectangle steel scaffolds (DS2R) increase with the number of bays. Although the height of the DS2R setup is higher than that of the 2D setup, the load capacity of the DS2R setup is still higher than that of the 2D setup, indicating that the strength of the combined setup of steel scaffolds is higher than that of pure door-type steel scaffolds. By applying the second loading using reusable materials, to simulate the load capacity of the steel scaffolds under the worst conditions, this study obtained the strength reduction factors of the steel scaffolds using reusable materials.
DOI: 10.12755/isec.res.2014.37
title: MECHANICAL PROPERTIES OF WARM MIX ASPHALT CONCRETE APPLICATION USING ADVERA

description: The article presents the study of physical characteristics of warm mix asphalt cementconcrete (WMA), components designed by the Marshall Method. Stability, flow rate,strength index, air void, and percent voids in mineral aggregate (VMA) of a total of 77specimens were examined as a general standard specification test of the Department ofHighways, Thailand. Limestone was used as aggregate. Adhesive mixtures of asphaltgrade 60/70 were mixed with admixture ?ADVERA? to the ratios of 0.20%, 0.25%,and 0.30% by weight of aggregate. WMA-mixing and compaction temperatures werecontrolled at 115?C, 120?C, and 125?C. The results were that the asphalt cementmixed with 0.25% of ADVERA (by total mixed) at 125?C shows the best mechanicalproperties standard, with higher value of stability (2,200lbs, i.e., more than the standard1,800lbs), flow rate, air void, VMA and hardness index. Finally, this study indicatesthat asphalt concrete added with admixture ADVERA (WMA) could reduce the mixingand compaction temperature during production processes from &gt;160?C to ? 125?C.
DOI: 10.12755/isec.res.2014.38
title: MECHANICAL PROPERTIES OF FLY ASH-BASED ALKALI-ACTIVATED CEMENT USING A STATISTICAL ANALYSIS TECHNIQUE

description: This paper presents the mechanical properties of fly ash-based alkali-activated cement (AAC). A statistical analysis method was used to determine the effect of mix proportion parameters on the dry density and compressive strength of fly ash-based AAC pastes and mortars. For that purpose, sample mixtures were designed according to Taguchi?s experimental design method, i.e., in a L9 orthogonal array. Four factors were selected: ?silica fume content? (SF), ?sand to solid ratio? (s/c), ?liquid to solid ratio? (l/s), and ?superplasticiser content? (SP). The experimental results were analysed by using signal to noise for quality control of each mixture, and analysis of variance (ANOVA) was used to determine the significant effect on the compressive strength of fly ash-based AAC. Furthermore, a regression-analysis method was used to predict the compressive strength according to the variation of the four factors. Results indicated that silica fume is the most influencing parameter on compressive strength, which could be decreased by superplasticiser and l/s ratio. There is no significant effect of sand-to-cementitious ratio on compressive strength of fly ash-based AAC. The dry density decreases as the sand-to-cementitious ratio is decreased. The increasing l/s ratio and superplasticiser dosage could further decrease the dry density of fly ash-based AAC.
DOI: 10.12755/isec.res.2014.39
title: HYDRATION AND MICROSTRUCTURAL PROPERTIES OF CEMENT PASTE CONTAINING NANO AND MICROSILICA

description: The influence of nano- and microsilica addition on ordinary Portland cement (OPC) pastes has been studied in terms of hydration and microstructural properties. Three different combinations of nano- and microsilica mixes were used. A constant water-binder ratio of 0.35 was maintained throughout the experiment. All samples were tested for initial and final setting time and compressive strengths were determined at the age of 3, 7, 28, and 90 days of hydration. The hydration products were examined by SDT and XRD analysis at various curing ages. The inclusion of nano- and microsilica reduced the initial and final setting time significantly, increased the compressive strength of hardened cement paste after 7 days of hydration, and reduced the amount of calcium hydroxide in the hardened paste compared to mixes without these nanoparticles.
DOI: 10.12755/isec.res.2014.40
title: MECHANICAL PROPERTIES OF A PVA FIBER REINFORCED ENGINEERED CEMENTITIOUS COMPOSITE

description: High Performance Fiber Reinforced Cementitious Composites (HPFRCCs) are promising construction materials characterized by tensile strain hardening behavior. Engineered Cementitious Composite (ECC) is a special type of HPFRCC developed with enhanced ductility and durability. Coarse aggregates are usually excluded from the ECC matrix, and the reported ECCs are typically produced with microsilica sand having a maximum grain size of 200 พm. In this paper, a PVA-ECC mixture containing local dune sand with a maximum grain size of 300 พm was developed, and its compressive and tensile properties were experimentally investigated. A dog-bone-shaped specimen and a rectangular-coupon-shaped specimen were both used in the tensile test, and it was found after extensive research that the dog-bone specimen was more suitable than the rectangular coupon specimen. The experimental results from the dog-bone specimens indicated that the newly-developed composite possessed good tensile strain-hardening behavior, with a high ultimate tensile strength, and the compressive strength was comparable to that of existing PVA-ECCs.
DOI: 10.6084/m9.figshare.9649400
title: Clinical and demographic data for a South African cohort of adults with Hepatitis B virus (HBV) infection

description: We here present the metadata and other supporting material for a prospectively recruited clinical cohort of adults with HBV infection, with and without coexisting HIV infection, recruited in Tygerberg Hospital, Cape Town, South Africa over a period of 1 year commencing July 2018. <br>Ethics approval was provided by University of Oxford Tropical Research Ethics Committee (ref. OXTREC 01-18), and University of Stellenbosch Ethics Committee (ref. N17/01/013). All participants provided written valid informed consent.<br><br>Suppl table 1: STROBE statement (STrengthening the Reporting of OBservational studies in Epidemiology) to support the quality of this observational cross-sectional study.<br>Suppl table 2: Raw data collected for 112 adults with chronic hepatitis B virus infection recruited into a cross-sectional cohort in Cape Town, South Africa. Information provided in xlsx and csv format.<br><br><br>
DOI: 10.12755/isec.res.2014.41
title: DURABILITY OF BASALT FIBERS IN CONCRETE MEDIUM

description: This study investigates the durability of basalt fiber following immersion in a range of chemical solutions representative of the concrete medium. The tests were conducted over a 62-day period and the solutions were sodium hydroxide, sodium chloride, sodium sulfate and combinations of the three. Weight loss was observed in all alkali solutions, with the worst being the combination of sodium hydroxide with sodium sulfate. The impact of chloride was minimal in the alkaline environment and reduced the impact of the sulfate when both were present. Microstructure analysis using a Scanning Electron Microscope (SEM) found that the silica structure present in basalt fibers was degraded by the OH- from an alkaline medium. The study suggests the need for modification or treatment of basalt fibers before use as fiber reinforcement in concrete.
DOI: 10.12755/isec.res.2014.42
title: MECHANICAL PROPERTIES OF FLY ASH BASED GEOPOLYMER CONCRETE WITH ADDITION OF GGBS

description: Concrete plays an important role in the construction industry worldwide. New technology has made for easier development of new types of construction and alternative materials in the concrete area. Cement is the major component in the production of concrete, but its manufacture causes environmental issues and thus there is a need for alternative materials. Geopolymer concrete is a new type of material with that potential, commonly formed by alkali activation of industrial alumina silicate byproducts, such as fly ash and ground granulated blast furnace slag (GGBS). For this paper, mechanical properties of geopolymer concrete with fly ash and GGBS cured under ambient temperatures were studied. Five different grades of concrete were considered. The results were encouraging: The workability of the geopolymer concrete was similar to that of conventional concrete. Experimental results of flexural and splitting tensile strength revealed insignificant variation compared to conventional concrete. The mechanical properties of fly ash and GGBS-based geopolymer concrete were comparable with conventional concrete.
DOI: 10.12755/isec.res.2014.43
title: SODIUM SILICATE ACTIVATED SLAG-FLY ASH CEMENT

description: This research examines an alternative binder, Alkali Activated Cement (AAC), examining the fresh and hardened mechanical properties of twelve AAC mortar mixes with varying mixture proportions of blast-furnace slag, fly ash, sodium silicate (the alkali activator), and additional water. In addition to the Slag-Fly Ash mortars, nine mixtures with blast-furnace slag, silica fume, aluminum hydrate, sodium silicate, and water were tested. For all mortars, the compressive strength was exponentially related to the water/activator-solids ratio. Mortar strengths at 28 days ranged from 5 MPa to 20 MPa. Increasing the slag to binder-solids ratio from 0.1 to 0.2 increased the strength with water to binder ratios from 0.2 to 0.4. However, rapid or almost instantaneous setting times were observed for a slag to binder-solids ratio of 0.2. The research concluded that using a carefully chosen mix design can prevent quick setting while still achieving high strength and acceptable workability. It is suggested the CaO to binder-solids ratio remain below 0.07; a sodium silicate to binder solids ratio of around 0.25 is optimal; a water to binder-solids ratio should be around 0.3. When replacing fly ash, a Si/Al ratio above 2 is recommended. This research concluded that other solids (Silica Fume and Aluminum Hydrate) could replace Slag and/or Fly Ash if the overall chemical balance of the system is maintained.
DOI: 10.12755/isec.res.2014.44
title: CHARACTERIZATION OF GEOPOLYMERS OBTAINED BY ALKALINE ACTIVATION OF METAKAOLIN WITH HIGH IRON CONTENT

description: The use of activated alkali aluminosilicate has been shown to be an economically-viable alternative that decreases the environmental impact of building construction material. Geopolymers are a type of activated alkali aluminosilicate that are rich in SiO2 and Al2O3, and harden within alkaline solutions. In this study, geopolymers obtained by alkaline activation of metakaolin with high iron content were characterized. The activation process used sodium hydroxide solutions at molarities of 12, 15, and 18 mol. The geopolymers were oven-dried at 85ฟC and at room temperature. The results identified the physicochemical and microstructural properties of the geopolymers and elucidated the activation process using the techniques: XRF, XRD, DTA, TG, DTG and DSC analysis. The results of the dynamic recrystallization indicated the presence of quartz, kaolinite, hematite, and muscovite in the samples. The DSC analyses showed an immediate reaction between the precursor material and the activator. The DTA results showed that the reactions began at low temperatures, where the dissolution of Si and Al occurred. The peaks that appear between 45ฟC and 60ฟC indicate that polymerization occurred through the condensation of Si and Al.
DOI: 10.12755/isec.res.2014.45
title: MECHANICAL PROPERTIES OF GEOPOLYMER CONCRETE WITH MINERAL ADMIXTURES

description: Concrete has contributed to the development of modern architectural culture, but the cement as an adhesive agent for concrete produces large amounts of carbon dioxide emissions into the air during the manufacturing process. This study researches the practical use of structure, through the verification of structural stability, for geopolymer concrete. This is part of the development of core technology for greenhouse gas emission reduction by reducing energy consumption in construction, an industry that occupies 25% of the total energy consumption in South Korea. According to the experimental results of chemical reaction (i.e., acid reaction, sulfate resistance reaction and corrosion caused by sodium chloride) of fly ash-based geopolymer concrete, the theory and SEM analysis demonstrated that geopolymer concrete was acid resistant, sulfate resistant, and resistant to corrosion caused by sodium chloride. The basic properties were understood through qualitative analysis of a geopolymer concrete specimen using SEM, and through a study on the practical use of structure by verifying structural stability for geopolymer concrete, as part of development of technology. After future experiments and tests, the best geopolymer concrete ratio and curing method will provide a guideline.
DOI: 10.12755/isec.res.2014.46
title: A STUDY OF MAINTENANCE METHODS OF DETERIORATED CONCRETE STRUCTURES WITH A RISK MATRIX

description: In this study, a risk matrix for maintaining the deteriorated RC structures was proposed, in which the difference between the results based on investigation and the actual performance was regarded as risk. The risk matrix was defined as the relation between the degree of material deterioration and the level of influence on the structural performance. This matrix was characterized by involving the range of risk reduction that serves as an index for determining the need for repair. In addition, survey results from an actual RC structure that had undergone the combined damage of frost and salt for more than forty years in Hokkaido were applied to the proposed risk matrix.
DOI: 10.12755/jgsee.res.2014.96
title: Electrochemical oxygen reduction reaction rate in polymer electrolyte fuel cell

description: Since optimization of the catalyst layer structure is necessary for reducing the cost of polymer electrolyte fuel cell (PEFC), formulation of the oxygen reduction reaction (ORR) rate in the cathode of PEFC is highly required for carrying out the numerical simulation for the design purpose. The ORR rate was measured with reducing the catalyst layer thickness for lowering the mass transfer resistance to oxygen, proton, and electron. Dependencies of the ORR rate on the oxygen partial pressure, relative humidity, and cell voltage were analyzed. The rate was of the first order with respect to the oxygen partial pressure up to 220 kPa. The first-order reaction rate constant was an exponential function of the cathode electromotive force. The exponent and preexponential factors were different in high and low cathode electromotive force regions. These kinetic parameters were formulated as functions of relative humidity. It was found that the exponent and preexponential factors were in strong correlation regardless of the relative humidity but depending on the cathode electromotive force region.