• Korean Journal of Materials Research
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• v.19 no.12
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• pp.692-698
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• 2009

Inconel 718 alloy has excellent mechanical properties at room temperature, high temperature and cryogenic conditions. UTS of base metal is about 900MPa at room temperature; this is increased up to 1300MPa after heat treatment & aging-hardening. Mechanical properties of Inconel 718 Alloy were similar to those shown in the the results for tensile test; mechanical properties of Inconel 718 alloy's GTAW were similar to those of base metal's properties at room temperature. Mechanical properties at cryogenic conditions were better than those at room temperature. Heat-treated Inconel 718, non- filler metal GTAW on Inconel 718 and GTAW used filler metal on Inconel 718's UTS was 1400MPa at cryogenic condition. As a result, the excellent mechanical properties of Inconel 718 alloy under cryogenic conditions was proved through tensile tests under cryogenic conditions. In addition, weldability of Inconel 718 alloy under cryogenic conditions was superior to that of its base-metal. In this case, UTS of hybrid joint (IS-G) at -100$^{\circ}C$ was 900MPa. Consequently, UTS of Inconel 718 alloy is estimated to increase from -100$^{\circ}C$ to a specific temperature below -100$^{\circ}C$. Therefore, Inconel 718 alloy is considered a pertinent material for the production of Lox Pipe under cryogenic conditions.

• Structural Engineering and Mechanics
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• v.45 no.3
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• pp.311-321
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• 2013

In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes $C_e$, $D_e$ and $E_e$, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.

• Computers and Concrete
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• v.26 no.4
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• pp.317-325
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• 2020

A precise estimation of the natural time period of buildings improves design quality, causes a significant reduction of the buildings' weight, and eventually leads to a cost-effective design. In this study, in order to optimise the reinforced concrete frames design, some symmetrical and unsymmetrical buildings composed of solid and hollow members have been simulated using finite element software SAP 2000. In numerical models, different parameters such as overturning moment, story drift, deflection, base reactions, and stiffness of the buildings were investigated and the results have been compared with strength and serviceability limit criteria proposed by Australian Standard (AS 3600 2018). Comparing the results of the numerical modelling with existing standards and performing a cost analysis proved the merits of hollow box sections compared to solid sections. Finally, based on numerical simulation results, two equations for natural time period of moment resisting reinforced concrete buildings have been presented. Both derived equations reflected higher degree of correlation and reliability with different complexities of building when compared with existing standards and relationships provided by other scholars. Therefore, these equations will assist practicing engineers to predict elastic behaivour of structures more precisely.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.509-514
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• 1993

The experiment was conducted to determine the effect of different fiber levels on milk production of crossbred Holstein milking cows fed urea-treated rice straw (UTS) as a roughage. Eight cows were allotted into 2 squares of 4 cows each with 4 treatments by a balanced design. The treatments were 17%, 22%, and 24% crude fiber (CF) diets and Thai feeding system (free choice of roughage and 1 kg of concentrates/2 kg of milk) as a control. Body weight change was not significantly different among the treatments during the experiment. Milk production (4% FCM) and milk protein content wee not different among the treatments, but milk fat content was low in the 17% CF group and high in the control group. Cows fed the 17% CF diet consumed less UTS and more concentrates than the others, and consequently total DM intake was not different among the treatments. The feed conversion ratio was significantly higher in the control. Feed cost per kg milk was lowest in the control and highest in the 17% CF diet. The fiber content of the diet would be more than 17%, preferably 22-24% for normally producing Thai crossbred Holstein cows when the UTS was fed as a main roughage source.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.70-78
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• 2012

Due to the variable nature of renewable energy resources and power demand by consumers, it is difficult to operate a power system installed with only one type of renewable energy resource. Grid-based renewable generation may be the only solution to overcome this problem. The conventional approach based on a low-voltage converter with power frequency transformer is commonly employed for grid connection of offshore renewable energy systems. Because of the heavy weight and large size of the transformer, the system can be expensive and complex in terms of installation and maintenance. In this paper, an 11-kV series connected H-bridge (SCHB) multilevel voltage source converter (VSC) is proposed to achieve a compact and light direct grid connection of renewable energy systems. This paper presents the design, simulation and analysis of a five level (5L)-SCHB and an eleven level (11L)-SCHB VSC for 11-kV grid-based renewable energy systems. The performance, cost, modulation scheme and harmonic spectra of the converter are analyzed.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.1-14
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• 2011

Water is the most precious resource to human being, but it is polluted by different organic compounds. Organic matter (OM) in aqeous solutions is one of the important parameters of concern for human and environmental impact, and thus, it is essential to better characterize specifically targeted organic matter in aggregated and individual level of concentrations. This review presents different analytical tools and protocols to investigate detailed properties and characterization. Physical, chemical and biological aspects of OM are envisaged in terms of traditional and advanced measurement methods.

• Steel and Composite Structures
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• v.43 no.4
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• pp.511-522
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• 2022

An experimental investigation to study the behaviour of connections between cold-formed steel (CFS) joist and plywood structural panel is presented in this paper. Material testing on CFS and plywood was carried out to assess their mechanical properties and behaviour. Push-out tests were conducted to determine the slip modulus and failure modes of three different shear connection types. The employed shear connectors in the study were; size 14 (6mm diameter) self-drilling screw, M12 coach screw, and M12 nut and bolt. The effective bending stiffness of composite cold-formed steel and plywood T-beam assembly is calculated based on the slip modulus values computed from push-out tests. The effective bending stiffness was increased by 25.5%, 18% and 30.2% for self-drilling screw, coach screw, nut and bolt, respectively, over the stiffness of cold-formed steel joist alone. This finding suggests the potential to enhance the structural performance of composite cold-formed steel and timber flooring system by mobilisation of composite action present between timber sheathing and CFS joist.

• Steel and Composite Structures
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• v.43 no.3
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• pp.403-417
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• 2022

Recently, there has been an increasing demand for buildings that allow rapid assembly of construction elements, have ample open space areas and are flexible in their final intended use. Accordingly, researchers have developed new competitive structures in terms of cost and efficiency, such as cold-formed steel and timber composite floors, to satisfy these requirements. Cold-formed steel and timber composite floors are light floors with relatively high stiffness, which allow for longer spans. As a result, they inherently have lower fundamental natural frequency and lower damping. Therefore, they are likely to undergo unwanted vibrations under the action of human activities such as walking. It is also quite expensive and complex to implement vibration control measures on problematic floors. In this study, a finite element model of a composite floor reported in the literature was developed and validated against four-point bending test results. The validated FE model was then utilised to examine the vibration behaviour of the investigated composite floor. Predictions obtained from the numerical model were compared against predictions from analytical formulas reported in the literature. Finally, the influence of various parameters on the vibration behaviour of the composite floor was studied and discussed.

• Corrosion Science and Technology
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• v.22 no.1
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• pp.55-63
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• 2023

The aim of this study was to propose a multiple linear regression (MLR) equation to predict ultimate tensile strength (UTS) of 316L stainless steel with unspecified pit corrosion. Tensile specimens with pit corrosion were prepared using a potentiostatic acceleration test method. Pit corrosion was characterized by measuring ten factors using a confocal laser microscope. Data were collected from 22 tensile tests. At 85% confidence level, total pit volume, maximum pit depth, mean ratio of surface area, and mean area were significant factors showing linear relationships with UTS. The MLR equation using these three significant factors at a 85% confidence level showed considerable prediction performance for UTS. Determination coefficient (R²) was 0.903 with training and test data sets. The yield strength ratio of 316L stainless steel was found to be around 0.85. All specimens with a pit corrosion presented a yield ratio of approximately 0.85 with R² of 0.998. Therefore, pit corrosion did not affect the yield ratio.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.195-203
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• 1990

Thirty-six yearling (18 bulls, 18 heifers) swamp buffaloes (Bubalus bubalis) with average liveweight $177{\pm}26kg$, were randomly allotted to receive 6 dietary treatments according to a $2{\times}3$ factorial arrangement in a completely randomized design (CRD). Factor A assigned for two types of straw; untreated rice straw (RS) and urea-treated (5%, w/w) rice straw (UTS). Factor B assigned for three ratio of roughage to concentrate (R:C) at 80:20, 50:50 and 20:80. Feeding trial lasted for 9 months during which respective feeds were offered at 3% body weight and adjusted at bi-weekly intervals using corresponding liveweights. Parameters measured under this experiment were feed intake, ruminal fluid for pH, $NH_3-N$, volatile fatty acids (VFA), liveweight change at bi-weekly intervals, carcass characteristics and cost-net profit analysis. It was found that intakes and digestion coefficients of DM, OM, CP except NDF and ADF were improved appreciably when ratio of concentrate increased. The average daily gain (ADG) and feed conversion ratio (FCR) were highest in group fed urea-treated rice straw at R:C levels of 20:80 (551.2 g/d, 10.7 kg/kg) and 50:50 (542.3 g/d, 10.6 kg/kg). It was obvious that FCR was best in the group fed on urea-treated rice straw (13.8 kg/kg) as compared to untreated rice straw fed-group (24 kg/kg). Carcass compositions of buffaloes measured resulted in 48.2 dressing percentage in all treatments offered at R:C levels of 50:50 and 20:80, however, loin eye area were 46.0, 53.6, 50.0 and $54.0cm^2$ for RS and UTS at respective levels of R:C. It was notable that carcass fat content was low which resulted in higher content of lean meat particularly in group fed UTS at 50:50 ratio R:C. Simple cost-net profit analysis was performed, it was found that net profits were obtained as follows 27, 30, -47, 44, 58, 22 $US/hd for respective treatment groups of RS and UTS at respective R:C levels. As shown, the best net profit resulted in group fed UTS at 50:50 R:C level.