• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.67-75
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• 2021

This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.

• Computers and Concrete
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• v.33 no.2
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• pp.147-162
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• 2024

This study presents a random-aggregate mesoscale model integrating the random distribution of the coarse aggerates and the damage mechanics of the mortar and interfacial transition zone (ITZ). This mesoscale model can generate the random distribution of the coarse aggregates according to the prescribed particle size distribution which enables the automation of the current methodology with different coarse aggregates' distribution. The main innovation of this work is to propose the "correction factor" to eliminate the dimensionally dependent mesh sensitivity of the concrete damaged plasticity (CDP) model. After implementing the correction factor through the user-defined subroutine in the randomly meshed mesoscale model, the predicted fracture resistance is in good agreement with the average experimental results of a series of geometrically similar single-edge-notched beams (SENB) concrete specimens. The simulated cracking pattern is also more realistic than the conventional concrete material models. The proposed random-aggregate mesoscale model hence demonstrates its validity in the application of concrete fracture failure and statistical size effect analysis.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.583-592
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• 2023

Celebes rainbow (Marosantherina ladigesi) is one of Indonesia's exported ornamental fish commodities, but the exploitation of this fish only relies on wild catches. The rise of unlimited fishing, especially those using poison, has changed the aquatic environment, threatening sustainability and causing fish extinction. This study aimed to evaluate the effectiveness of several types of feed in improving the absolute growth rate (AGR), specific growth rate (SGR), survival rate (SR), feed conversion ratio (FCR), feed efficiency (FE), hematology, and immune response of Celebes rainbow. The fish used in this study were male ornamental Celebes rainbow (M. ladigesi) weighing 1.32 ± 0.21 g/ind, reared in 54 L-aquariums at a stocking density of 30 individuals/aquarium for six weeks. The fish were fed according to the test diet consisting of live Tubifex sp worms, dry Tubifex sp worms, Spirulina platensis, and crumble pellets. The parameters observed were AGR, SGR, SR, FCR, FE, hematology, intestinal histology, liver histology, and a challenge test with the pathogenic bacteria Aeromonas hydrophila. The results showed that fish-fed live Tubifex sp worms had better AGR, SGR, SR, FCR, FE, hematology, and disease resistance compared to all other treatments. These results indicate that live Tubifex sp worms are the best feed for rearing Celebes rainbow.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.4983-4988
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• 2013

Objectives: To establish a taxol-resistant cell line of human ovarian carcinoma (A2780/Taxol) and investigate its biological features. Methods: The drug-resistant cell line (A2780/Taxol) was established by continuous stepwise selection with increasing concentrations of Taxol. Cell morphology was assessed by microscopy and growth curves were generated with in vitro and in vivo tumor xenograft models. With rhodamine123 (Rh123) assays, cell cycle distribution and the apoptotic rate were analyzed by flow cytometry (FCM). Drug resistance-related and signal associated proteins, including P-gp, MRPs, caveolin-1, PKC-${\alpha}$, Akt, ERK1/2, were detected by Western blotting. Results: A2780/Taxol cells were established with stable resistance to taxol. The drug resistance index (RI) was 430.7. Cross-resistance to other drugs was also shown, but there was no significant change to radioresistance. Compared with parental cells, A2780/Taxol cells were significantly heteromorphous, with a significant delay in population doubling time and reduced uptake of Rh123 (p<0.01). In vivo, tumor take by A2780 cells was 80%, and tumor volume increased gradually. In contrast, with A2780/Taxol cells in xenograft models there was no tumor development. FCM analysis revealed that A2780/Taxol cells had a higher percentage of G0/G1 and lower S phase, but no changes of G2 phase and the apoptosis rate. Expression of P-gp, MRP1, MRP2, BCRP, LRP, caveolin-1, PKC-${\alpha}$, Phospho-ERK1/2 and Phospho-JNK protein was significantly up-regulated, while Akt and p38 MARK protein expression was not changed in A2780/Taxol cells. Conclusion: The A2780/Taxol cell line is an ideal model to investigate the mechanism of muti-drug resistance related to overexpression of drug-resistance associated proteins and activation of the PKC-${\alpha}/ERK$ (JNK) signaling pathway.

• Journal of Magnetics
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• v.19 no.3
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• pp.291-294
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• 2014

In this paper, we examine the electrical and magnetic properties of three different types of shield materials used for wireless power transfer systems: namely, FeSiAl-composite, NiZn-ferrite, and FeSi-amorphous types. The power transfer efficiency and resistance of an RX coil are measured, while varying the shield thickness. For all three types, a thicker shield provides better power transfer efficiency. Analysis of the measurements shows that the FeSiAl-composite type is suitable for systems with size limitation. In terms of magnetic properties, the FeSi-amorphous type shows the best features, and is suited to high power applications. This work can be used as a guideline to select suitable shielding material in various wireless power transfer systems.

• Asia pacific journal of information systems
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• v.17 no.1
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• pp.1-31
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• 2007

This research proposes a conceptual framework to highlight the importance of change management after firms implement ERP systems. With ERP, firms need to rework their business processes to make information flow smoothly within organizations. Firms cannot realize expected returns from ERP investments unless changes are effectively managed after ERP systems are put into operation. The research model is empirically tested using data collected from over 170 firms that had used ERP systems at least for more than one year. Our analysis reveals that the eventual success of ERP systems depends on effective change management after ERP implementation, supporting the existence of the 'valley of despair.

• Journal of Technology Innovation
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• v.12 no.3
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• pp.1-24
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• 2004

E-Learning is another way of teaching and learning. E-learning is a networked phenomenon allowing for instant revisions and distribution, and goes beyond training and instruction to the delivery of information and tools to improve performance. The benefits of e-learning are many, including cost-effectiveness, enhanced responsiveness to change, consistency, timely content, flexible accessibility, and providing customer value. The proponents of e-learning stress the importance of using communities of interest to support and enhance the learning process. They also emphasizes that people learn more effectively when they interact and are involved with other people participating in similar endeavors. Although the role of e-learning in higher education has significantly increased, the resistance to new technology by professors and lecturers in university and colleges worldwide remains high. The purpose of this study is to identify the determinants of attitude and planned behavior toward e-learning class in universities. A survey methodology was used to investigate a proposed model of influence, and structural equation modeling was used to analyze the results. The hypothesized model was largely supported by this analysis, and the overall results indicate that attitude toward e-learning systems is mostly influenced by the perceived ease of use as well as the level of perceived usefulness, where both factors are influenced by years of experiences in using cyber system and the technical support level. As in other TAM related research, it can be concluded that the perceived ease of use and perceived usefulness contribute to the future use of e-learning system.

• Information Systems Review
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• v.10 no.3
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• pp.257-287
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• 2008

Grounded in the prior literatures on acceptance and diffusion of IT and innovation in the level of organization research, 3 major constructional factors such as Motivation, IT resistance, and IT change management were investigated to suggest propositions from 15 multi-cases of PLM from 6 different companies in Automotive OEMs and suppliers, and we posited that the diffusion is continued only when motivation is stronger enough to overcome IT resistance as a fundamental finding and basis of this research on PLM acceptance and diffusion. The Motivation was found to be initiated and categorized from three different factors such as environmental factors, organizational factors, and technological factors, providing key propositions for further research: (1)The Automotive suppliers, contrary to OEM, are affected more by the demand of inter-connectivity as an environmental factor, while the other factors are similarly influencing to them, (2)The big organizations are influenced more by the champion, while the small organizations get influenced more by leader. (3)When the trend, inter-connectivity and complexity get stronger, the motivation gets more strongly influenced by the perceived benefit in the technological context. Regarding Change management we suggests IT change management is supportive to overcome IT resistance and also to enforce Motivation, and the critical mass exists differently according to the market maturity adopted, and more market matured technology has lower critical mass, implies less requirement of IT change management than less market matured technology.

• Tribology and Lubricants
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• v.34 no.6
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• pp.254-261
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• 2018

In order to reduce resistance torque and energy loss, minimizing friction between race surface and rolling elements of a bearing is necessary. Recently, to reduce friction in bearing element, solid lubricant coating for the bearing raceway surface has been receiving much attention. Considering the operating conditions of real bearings, verifying the effect of solid lubricant coatings under extreme conditions of high load that is more than 1 GPa is necessary. In this study, we evaluated the friction and wear characteristics of SUJ2 bearing steels deposited by carbon-based coatings (Si-DLC, ta-C), $MoS_2$ and graphite. In case of $MoS_2$ and graphite coatings, different surface treatments were applied to the coatings to verify the effect of surface treatment. A pin-on-disc type tribotester was used to evaluate the tribological characteristics of the coatings. It was possible to quantitatively estimate the friction and wear characteristics of solid lubricant under dry and lubrication conditions. The carbon-based coatings improved the friction and wear properties of SUJ2 bearing steels under the high load condition, but $MoS_2$ and graphite coatings were not suitable for high load conditions due to its low hardness. Different friction and wear behaviors were found for different substrate surface treatment method. Also, it was confirmed that solid lubricant coatings had a more positive effect than just applying the lubricant for improving the tribological characteristics.

• Advances in nano research
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• v.14 no.3
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• pp.235-246
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• 2023

Nanotechnology, like any other revolutionary innovation in materials science, has significantly influenced the level of competition in sports. Nanotechnology provides various benefits and enormous potential to enhance athletic equipment, making players safer, more comfortable, and more agile. Various sporting equipment is being infused with nanomaterials, including carbon nanotubes (CNTs), silica nanoparticles (SNPs), nanoclays fullerenes, etc., to enhance athlete and equipment performance. Each of these nanomaterials gives athletic equipment an extra benefit like high strength and stiffness, longevity, decreased weight, abrasion resistance, etc. This paper mechanically analysis the structural strength of tennis equipment to avoid injury. As a result, the bending forces are applied to the reinforced structures to investigate their durability.