Application of Adaptive Neuro-Fuzzy Inference System in High Strength Concrete

Adaptive Neuro-Fuzzy Inference System is growing to predict nonlinear behaviour of construction materials. However due to wide variety of parameters in this type of artificial intelligent machine, selecting the proper optimization methods together with the best fitting membership functions strongly affect the accuracy of prediction. In this study the nonlinear relation between splitting tensile strength and modulus of elasticity with compressive strength of high strength concrete is modelled and the effect of different effective parameters of Adaptive Neuro-Fuzzy Inference System is investigated on these models. To specify the best arrangements of parameters in the System to utilize in high strength concrete properties, different combinations of optimization methods and membership functions in the Sugeno system have been applied on more than 300 previously conducted experimental datasets. Both the grid partition and sub-clustering methods have been applied to models and compared to get the best combination of parameters

Paraffin as Phase Change Material

Nowadays, numerous problems, including the environmental problem caused by fossil fuels, have led to greater attention to the optimal use of energy and the development of renewable energy. One of the most important parts of using energy efficiently is storing it. Among the many ways introduced for energy storage, thermal energy storage, including latent heat, is among the most interesting. This storage is done with materials called phase change materials (PCMs). These materials store the energy in the form of latent heat at constant temperature during the phase transition, discussed in this chapter, and release the same stored energy in the crystallization process. These materials are mainly classified into three categories: organic, inorganic, and eutectics. Today, these materials are widely used with different properties in a variety of fields. Paraffin is one of the most important organic PCMs due to its numerous advantages that will be discussed in the following sections. From the methods of using paraffinic PCMs, two main methods, encapsulation and shape-stable PCMs, are discussed in detail. On the whole, this chapter of the book attempts to briefly discuss paraffins and their unique role in thermal energy storage systems as phase change materials

Instantaneous deflection of self-compacting and lightweight concrete slabs at early-age

© 2018 Growing Science Ltd. All rights reserved. This paper describes laboratory tests on twelve simply-supported one-way slabs including four lightweight concrete slabs in this study and previously conducted experiments on eight self-compacting reinforced concrete slabs subjected to loading at the age of 14 days. All slab were identical by dimensions of 3.8 m long supported on 3.5 m span, 400 mm wide, and 161 mm deep with 4N12 bars at an effective depth of 136 mm providing a reinforcement ratio of 0.008. After seven days moist-curing, the specimens were removed from the formworks and subjected to different values of the uniformly distributed loading including the self-weight of slabs. The mid-span deflection of slabs was recorded immediately after putting the loading blocks on the slabs. Despite close values of the compressive strength of the mixtures, the obtained results validate the effect of the concrete type on the instantaneous deflection of slabs. A wide range of existing models of the effective stiffness of reinforced concrete section were investigated to predict the instantaneous deflection of slabs. Majority of the models are developed for conventional concrete. Comparing the predicted and experimental results of mid-span deflection confirmed that the existing models are inadequate for lightly reinforced specimens such as slabs. New models are proposed and verified to predict the effective moment of inertia in the slabs with and without fiber reinforcing concretes

Predicition of Compressive Strength in Light-Weight Self-Compacting Concrete by ANFIS Analytical Model

© 2015 by B. Vakhshouri, S. Nejadi. Light-weight Self-Compacting Concrete (LWSCC) might be the answer to the increasing construction requirements of slenderer and more heavily reinforced structural elements. However there are limited studies to prove its ability in real construction projects. In conjunction with the traditional methods, artificial intelligent based modeling methods have been applied to simulate the non-linear and complex behavior of concrete in the recent years. Twenty one laboratory experimental investigations on the mechanical properties of LWSCC; published in recent 12 years have been analyzed in this study. The collected information is used to investigate the relationship between compressive strength, elasticity modulus and splitting tensile strength in LWSCC. Analytically proposed model in ANFIS is verified by multi factor linear regression analysis. Comparing the estimated results, ANFIS analysis gives more compatible results and is preferred to estimate the properties of LWSCC

原子間力顕微鏡補助による走査トンネル顕微鏡を用いたMoS2ナノシートの局所状態密度観察

Tohoku University須藤彰三課

Comparative study of the long-term deflection of conventional and self-compacting concrete with light-weight concrete slabs

University of Technology Sydney. Faculty of Engineering and Information Technology.Long-term deflection of concrete slabs is often the main governing design criteria to determine the appropriate thickness of the slabs to meet the required serviceability limit state. Due to the nonlinear nature of the material, predicting the long-term deflection of concrete structures is complex. Also, the complicated behaviour of concrete in the presence of reinforcement makes the problem more challenging to study. In general, codes of practice give an overall estimation of the long-term deflection as a multiplier of the short-term or elastic deflection of concrete structures. Such estimation sometimes may lead to an entirely wrong prediction of deflection and consequently unsafe, unrealistic and unprofitable concrete design and construction. Recent developments in concrete technology have led to produce new construction materials by significant strength and performance features. Many of these developments are engineered solutions to technical and commercial problems by either improvement of the current practices or overcoming of limitations in the existing construction technology. Lightweight and self-compacting concrete are the main two innovative concrete types used in the construction industry along with conventional concrete. This study examines and evaluates the time-dependent deflection of reinforced concrete one-way slabs made of two concrete types versus the conventional concrete. The presented investigation comprises both experimental and analytical components. The experimental part consists of laboratory investigation of the time-dependent flexural deflection and monitoring of the strains in reinforced concrete slabs. Since lightweight concrete is very prevalent in building construction in Australia, and there are limited studies on its long-term behaviour, the current study examines the lightweight concrete slabs identical to the previously tested conventional concrete slabs (Nejadi, 2005) and self-compacting concrete slabs (Aslani, 2014) subjected to the identical long-term loading. In addition, an analytical study consists of verification of the recorded experimental data and parametric study of the effective factors in the time-dependent behaviour and deflection of the conventional and self-compacting concrete slabs are conducted. Recently developed high-capable ATENA software is utilized in the numerical analysis. Load-deflection behaviour of the slabs under short-term loading is also recorded and compared with those of self-compacting and conventional concrete slabs. Finally, the results of this study are used to evaluate and verify the existing and proposed models associated with the parameters that affect the flexural deflection of reinforced concrete slabs with different types of concrete

Influences of side wall angle on heat transfer of power-law fluids in trapezoidal enclosures

In recent years, there is an important increase in technological applications of non-Newtonian fluids (NNF). NNFs are preferred over Newtonian fluids (NF) because of their superior hydrodynamic and thermal properties. NNFs are particularly used as damping fluid in shock absorbers, raw material for making of armors in defense industry and insulator in thermal systems. The use of NNF has become widespread in thermal systems in order to prevent over-heating problem which affects the efficiency. This study presents a numerical analysis for the natural convection in a two dimensional trapezoidal (isosceles trapezoid) enclosure filled with power-law NNF. The effects of various parameters are investigated on heat transfer on the bottom wall by developing a two dimensional model of such a cell. The bottom edge of the trapezoidal enclosure is considered as hot, top edge as cold while the side walls are considered as adiabatic. The considered parameters are power-law index (n) and Rayleigh number (Ra) and also the trapezoid side wall angle altering in the range of 0≤≤20. The power-law index has been varied in the range of 0.6≤≤1.8 and Rayleigh number in the range of 103≤≤105 while Prandtl number has been kept constant as 1000. The results reveal that the mean Nusselt number (̅̅̅̅ ) on bottom wall of trapezoid increases by increasing trapezoid angle and decreasing power-law index. According to evidences of the study, it may be suggested that the use of power-law NNFs may contribute to increase efficiency by averting the over-heating problems in trapezoidal thermal systems which are regarded as a significant application field in green and renewable energy systems.papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Colon-Specific Drug Delivery Behavior of pH-Responsive PMAA/Perlite Composite

The preparation, characterization, and in vitro release of 5-aminosalicylic acid (5-ASA) from methacrylic acid (MAA)/perlite composites (APC) prepared via a sol–gel route are reported. The free-radical graft polymerization of methacrylic acid (MAA) onto perlite particles was studied experimentally. The grafting procedure consisted of surface activation with 3-(trimethoxysilyl) propyl methacrylate (TSPA), followed by free-radical graft polymerization of methacrylic acid (MAA) in ethyl acetate with 2,2′-azobisisobutyronitrile (AIBN) initiator. The composition of the composites hybrid materials was determined by FTIR spectroscopy. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). The dried composites were immersed in a saturated solution of 5-ASA in water overnight and dried over a period of three days at room temperature and the in vitro release profiles were established separately in both (SGF, pH 1) and (SIF, pH 7.4). The 5-ASA concentration of the solution was measured using a UV-Vis spectrophotometer (205 nm) at different time intervals. The in vitro drug release test revealed that the release rate of 5-ASA in buffer solutions increased with the silica content in the composites; on the contrary, the increase of the content of 3-(trimethoxysilyl)propyl methacrylate (TSPA), a coupling agent, decreased the drug release rate