This study represents the results of an empirical program investigating the behavior of square reinforced concrete (RC) columns retrofitted using longitudinal carbon fiber‐reinforced polymer (CFRP) ...composites under simulated seismic loading. The main challenges to tackle are the premature buckling and the debonding of the longitudinal FRP composites on the tension and compression sides of the columns, respectively. To postpone both, the two versions of the grooving methods (GM), that is, the externally bonded reinforcement on grooves (EBROG) and the externally bonded reinforcement in grooves (EBRIG), were employed and the results were compared with those obtained under the traditional externally bonded reinforcement (EBR) procedure. Another aspect of the study involves investigating the influence of the recently developed corner strip‐batten (CSB) method on confining column specimens. For these purposes, seven half‐scale RC columns strengthened using FRP sheets were subjected to reversal cyclic loading. Experimental results exhibited that using the EBRIG and EBROG methods simultaneously with CSB technique could prevent altogether the debonding and buckling of longitudinal CFRP sheets. It was also found that the application of FRP strips utilizing the GM and CSB methods could produce an important increment in the performance of the RC columns in different terms such as ductility and lateral strength.
•A novel tube insert (bidirectional conical strip inserts) is proposed for heat transfer enhancement.•Multiple longitudinal swirl flow structure is formed in tube with the inserts.•Effects of ...geometric parameters are examined numerically.•Correlation formulas for Nusselt number and friction factor are derived.
In the present work, a novel tube insert (bidirectional conical strip inserts) is proposed, and the heat transfer performance and flow characteristics of this insert are studied numerically. Effects of three geometric parameters (numbers of bidirectional conical strip (n), central angle (α) and pitch ratio (P∗ = p/D)) are also investigated. The results indicate that cold fluid in the core region and the hot fluid near the tube wall are rapidly exchanged as the fluid flows through the bidirectional conical strip, and multiple longitudinal swirling flows are formed downstream of the bidirectional conical strip. Therefore, the heat transfer (the Nusselt number) is significantly enhanced by 2.35–9.85 times compared to the smooth tube. Moreover, because of the cooperation between the forward and the reverse conical strips, the formation of the dead zone and eddy on the back of the conical strips is inhibited. Thus, the increase in flow resistance is smaller than many other published works, as the friction factor is enhanced to 2.37–21.18 times of the smooth tube. The overall heat transfer performance (PEC value) is located in range of 1.75–3.93. Both the Nusselt number and friction factor increase with the increasing numbers of bidirectional conical strip, central angle and the decreasing pitch ratio. However, the friction factor is more sensitive to geometric parameters, so the maximum overall heat transfer performance (PEC value) is obtained at moderate geometric parameters (n = 3, α = 40° and P* = 3). In addition, Correlation formulas for Nusselt number and friction factor are derived.
•Flat tube compact heat exchangers with offset strip fins in a very short flow depth is investigated.•Offset strip fins are composed of non-uniform uninterrupted fin length on varying ...intermediates.•The effect of flow direction on the thermal and hydraulic performance with non-uniform uninterrupted fin length is presented.
In this particular work, the flat tube with mini-channel compact heat exchangers with offset strip fins by non-uniform uninterrupted fin length are investigated experimentally. The tests are performed by four different types of flat tube compact heat exchangers. The tests are conducted in the range of 600 < Rea < 2000, while water as the heat transfer fluid is circulated at the inlet of the heat exchanger and regulated by a water bath at a temperature of 42 °C. The performance of the heat exchangers is assessed by using Colburn j-factor, friction factor f, area goodness factor j / f and volume goodness factor j / f1/3. According to the obtained outcomes, the compact heat exchanger with bigger pass number provides better heat transfer. Two different types of strip fins with non-uniform uninterrupted fin length have been tested. The heat exchanger group with 1.55 m length of flat tube shows almost 40% higher performance than the heat exchanger group with 1.20 m length of flat tube.
Gold immunochromatographic strip (GICS) has become a popular membrane-based diagnostic tool in a variety of settings due to its sensitivity, simplicity and rapidness. This paper aimed to develop a ...framework of automatic image inspection to further improve the sensitivity as well as the quantitative performance of the GICS systems. As one of the latest methodologies in machine learning, the deep belief network (DBN) is applied, for the first time, to quantitative analysis of GICS images with hope to segment the test and control lines with a high accuracy. It is remarkable that the exploited DBN is capable of simultaneously learning three proposed features including intensity, distance and difference to distinguish the test and control lines from the region of interest that are obtained by preprocessing the GICS images. Several indices are proposed to evaluate the proposed method. The experiment results show the feasibility and effectiveness of the DBN in the sense that it provides a robust image processing methodology for quantitative analysis of GICS.
The effectiveness of the use of the serial image method to improve the ability of students (experimental research at the Nur Al-Falah Melabuh Islamic Boarding School Institute) Kitabah (writing ...skills) is a process of brain work in expressing the contents of the human mind. Insya' can help students express their thoughts in the correct written form. Some students at Maʼhad Nurul Falah Meulaboh are not able to compose simple sentences (number of mufidah) properly and correctly and they have difficulty in compiling these sentences. One of the factors that affect students' understanding difficulties and students' weak understanding insya' is caused by teachers who do not use appropriate media in learning. The purpose of this research is to determine the effectiveness of using strip drawing media in learning insya’ in Maʼhad Nurul Falah Meulaboh. The research method used in this research is the experimental method and to collect data, the researcher uses direct observation and test. . In terms of data analysis, the researcher used the T-Test formula. The results showed that the use of strip drawing media was effective in improving students' ability in learning insya' where the highest score after using strip drawing media reached 90 and this was also shown from the t-test score which was greater than the t-table score, which was 4.25 8.49.
First published in 1985, this book (now with a new preface by the author) analyses the reasons for the rejection of a two-state solution by Israel and Palestine. It then sets up a vision of a ...possible solution which, by taking account of the subjective fears and aspirations of the parties, may be regarded as more feasible.
To optimize the technology of rolling coils on a broad-strip mill of the casting and rolling complex (CRC), a technology for continuous casting of steel with a change in the thickness of the slab ...during the casting process has been developed and implemented. This process is possible for a thin slab casting machine (TSCM) with roller guide segments, the design features of which allow the compression of a continuously cast billet with a liquid core. A special algorithm has been developed and integrated into the TSCM automation system for changing the thickness of the slab by controlling the hydraulic cylinders of the roller segments, which ensure the reduction of the continuously cast billet in a certain order. The conditions affecting the duration of the process of changing the thickness of the slab during casting and the length of the transition along the thickness of the slab have been determined.
•Upward two-phase flow in confined geometries such as offset-strip fins.•Influence of operating conditions on upward two-phase flow.•Influence of the use of binary mixtures on heat and mass transfer ...modes.•Introduction of new correlations for pressure drops and heat transfer coefficients for binary zeotropic mixtures in offset strip fins.
The current study focuses on an experimental investigation of upward vertical two-phase flow of binary mixtures in complex geometries composed of offset-strip fins. The flow boiling of a mixture containing 52% mol/mol of R-134a and 48% mol/mol of R-245fa was visualized. The ranges of mass flux and heat flux investigated were 11 – 25 kg.m−2.s−1 and 9 – 23 kW.m−2 respectively. The test section is an offset-strip finned passage whose hydraulic diameter is 1.75 mm. The operating pressure ranges from 2 to 5 bar absolute. The temperature glide of the used binary mixture ranges from 14 to 16 °C. Different flow regimes were identified along the test section such as bubbly, slug and annular regimes. The impact of strip-fins and mass flux on flow maps was analysed in this study. The pressure drop was analyzed and the obtained data were gathered to propose a new correlation for R-134a/R-245fa mixture in offset-strip fins. The local heat transfer coefficient was calculated and it has been found that nucleate boiling was the predominant mode of heat transfer.
Open strip mining of coal results in loss of natural carbon (C) sink and increased emission of CO2 into the atmosphere. A field study was carried out at five revegetated coal mine lands (7, 8, 9, 10 ...and 11years) to assess the impact of the reclamation on soil properties, accretion of soil organic C (SOC) and nitrogen (N) stock, changes in ecosystem C pool and soil CO2 flux. We estimated the presence of C in the tree biomass, soils, litter and microbial biomass to determine the total C sequestration potential of the post mining reclaimed land. To determine the C sequestration of the reclaimed ecosystem, soil CO2 flux was measured along with the CO2 sequestration. Reclaimed mine soil (RMS) fertility increased along the age of reclamation and decreases with the soil depths that may be attributed to the change in mine soils characteristics and plant growth. After 7 to 11years of reclamation, SOC and N stocks increased two times. SOC sequestration (1.71MgCha−1year−1) and total ecosystem C pool (3.72MgCha−1year−1) increased with the age of reclamation (CO2 equivalent: 13.63MgCO2ha−1year−1). After 11years of reclamation, soil CO2 flux (2.36±0.95μmolm−2s−1) was found four times higher than the natural forest soils (Shorea robusta Gaertn. F). The study shows that reclaimed mine land can act as a source/sink of CO2 in the terrestrial ecosystem and plays an important role to offset increased emission of CO2 in the atmosphere.
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•Reclamation of mine degraded land increases ecosystem carbon (C) pool.•SOC and available N stocks increased 2 folds after 7 to 11years of revegetation.•Ecosystem C pool is depending on the soil characteristics and age of revegetation.•RMS CO2 flux is four times higher than that of natural forest soil.•Ecosystem C pool increased at a rate of 3.72MgCha−1year−1.
With the increasing application of flexible pipes in deep-sea operations, higher processing accuracy is required for the individual metal layers of these pipes to withstand greater service loads. In ...the helical winding production of the tensile armour layer, the accuracy of tension control significantly affects the uniformity of the steel strip after winding. To ensure tensile stability during the processing of steel strips, a tensile model for the manufacturing process is proposed. This model can be used to predict the magnitude and trend of tension fluctuations caused by the unwinding device, facilitating the design of a constant tension control system for steel strips based on an integral separation fuzzy PID algorithm. This system can achieve rapid convergence of tension during large tension fluctuations. The experimental results confirm the accuracy of the prediction model and the reliability and effectiveness of the designed tension control system. With this system, the tension fluctuation range is reduced by nearly 40%, and the average value of the standard deviation of the spacing after steel strip winding is decreased by 0.21 mm, demonstrating the potential of this approach for improving the manufacturing quality of the tensile armour layer of flexible pipes.
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