Effect Of Different Materials Research Articles

Statistical analysis on the fracture behavior of rubberized steel fiber reinforced recycled aggregate concrete based on acoustic emission

Rubberized steel fiber reinforced recycled aggregate concrete (RSRAC) is an environmental-friendly building material produced from waste concrete and tires. However, the evolution of fracture behavior in RSRAC under flexural loads still remains unknown, and the individual as well as the coupling effects of recycled aggregate (RA), crumb rubber, and steel fiber are also unclear. In this paper, four groups of specimens with different contents of RA, crumb rubber, and steel fiber were prepared, and a series of four-point bending tests were conducted. The loading process was monitored by acoustic emission (AE) in real-time, and the fracture behavior was then analyzed through AE signals using multiple statistical methods including Ib-value method, cumulative energy analysis, intensity analysis, K-means clustering and RA-AF analysis. Scanning electron microscope (SEM) was also employed to give explanations in microscale. Results show that the fracture process of RSRAC can be divided into micro-crack stage, main collapse stage, and residual stage. A fluctuation greater than 0.06 in Ib-value could be regarded as a criterion for this division. AE counts, cumulative AE energy as well as cluster analysis are also effective in judging the sub-stages. The dominant failure mode in micro-crack stage and residual stage is tensile crack, and shear cracks mainly occur in the main collapse stage. SEM investigation has revealed that the shear cracks in the main collapse stage mainly come from the shear failure of acicular crystals or micro-chimeras at the interface. For effects of different materials, it is found that rubber can reduce the brittleness and improve the ductility of the concrete, but will lower the strength properties. Steel fiber can increase the brittleness of the fracture behavior and reduce the ductility, but is favorable to strength. While RA can increase the brittleness and is harmful to both ductility and strength. The coexistence of rubber and steel fiber can significantly shorten the residual stage. The work is expected to provide a deeper understanding on the properties of RSRAC.

Classification and Zoning of Improved Materials of Weathered Redbed Soil in China Based on the Integrity of Mud Skin

Natural redbeds are widely distributed throughout China. Ecological restoration entails implementing measures according to the local conditions and obtaining local materials, ensuring ecological environment conservation and restoration in a scientific manner. The mud skin of weathered redbed soil is often used to control soil desertification and repair slope, and its integrity is important to measure the repairing effect. However, most of the materials used for the improvement of weathered redbed soil contain harmful chemicals, bear high costs, and aggravate environmental pollution. At present, the knowledge about different kinds of improvement materials for Chinese different zones is unclear. To solve this problem, we considered naturally weathered redbed soil as the raw material, selected 77 kinds of improved materials, and tested the integrity of the natural redbed weathered soil after adding the improved material; then, we compared it with the natural redbed weathered soil with no added materials. Then, we put forth a classification standard for the materials, discussed the driving environmental factors, formulated the suitable zoning of the materials, and defined the improvement effects of different materials on the weathered redbed soil in different regions of China. The results suggested that, for weathered redbed soil, nano water-based adhesives were most suitable for the south-western, north-western, south-eastern, north-eastern, and northern regions of China and can be widely used in other regions as well. Starch was the least suitable material for the north-western, north-eastern, and northern regions of China. The most unsuitable material for South-West China was larch tannin extract; wormwood straw was the most unsuitable for South-East China. The modified material that was not suitable for use in most zones was starch. Thus, our study provides a concrete scientific basis regarding the effectiveness of different materials in addressing natural hazards caused by weathered redbed soil in China.

Effects of Different Materials on Biogas Production during Anaerobic Digestion of Food Waste

One of the best methods for turning different types of biomass into clean energy is anaerobic digestion (AD). Organic and inorganic additives may be employed in the AD process to increase biogas output. It has been demonstrated that inorganic additives, such as micronutrients, can improve the efficiency of biogas producing reactors. These trace items can be introduced to the AD process as powders. The use of metal oxides in engineering and environmental research has become more popular. This study focuses on the role of TiO2 and ZnO/Ag powders on anaerobic digestion. Food waste studies on biochemical methane potential were performed with and without TiO2 and ZnO/Ag powders to examine their impact on AD. All powders are grown through the hydrothermal procedure, which has proved to be environmentally friendly and low in cost, presenting the capability to simply control the materials’ characteristics at mild temperatures. The addition of ZnO/Ag and TiO2 improved the biogas cumulative yield by 12 and 44%, respectively, compared to the control reactor. In addition, volatile solids (VS) removal efficiency increased by 5.7% in the food wastes (FW) and TiO2 reactor, while total chemical oxygen demand (TCOD) removal efficiency increased by 22% after the addition of ZnO/Ag.

Research Progress on Improvement of Saline Alkali Soil

Soil salinization is one of the most important issues threatening agricultural production, food security and sustainability in arid and semi-arid regions worldwide. The improvement and comprehensive utilization of saline alkali soil is of great significance for cultivating healthy soil, ensuring global food security and mitigating climate change. This paper summarized the research progress of saline alkali soil improvement technology, and described briefly the causes of saline-alkali land. Moreover, the physical, chemical and biological methods of saline-alkali land improvement were analyzed. The improvement characteristics and effects of different materials and technologies are described. And we proposed suggestions for future research and development of desalination materials and technologies to provide a useful reference for the research and development of efficient improvement technology of saline-alkali soil, and accelerate the improvement of saline-alkali land and improve the quality of cultivated land to a greater extent.

Prediction of Solid Propellant Burning Rate Characteristics Using Machine Learning Techniques

AbstractWhen formulating a new solid propellant, one of the most important aspects of its performance is the burning rate's response to a change in pressure. For this reason, it is useful to be able to predict the burning rate response of a given propellant before the propellant formulation is created such that experimental trade studies are minimized or reduced in scale. While many theoretical and phenomenological models have been proposed to explain various aspects of energetic material combustion, little work has been made publicly available in the application of machine learning models to predicting solid propellant burning rates. To facilitate model creation, the material formulation and burning rate parameters for over 600 publicly available propellant formulations have been collected into a coherent data set. This work utilizes the large amount of publicly available data to inform a random forest machine learning (ML) model in the prediction of solid propellant burning rate parameters. This ML model operates over a large parameter space including ammonium perchlorate composite, plastic bonded high explosive, and double‐base propellants. The model's accuracy, adaptability, and prediction capabilities are presented and discussed. The effects of different materials on a propellant's expected burning rate are examined.

Stab-Resistant Polymers-Recent Developments in Materials and Structures.

Stab-resistant garments have been used for centuries, utilizing metals, paper, or polymeric structures, often inspired by natural structures such as scales. Nowadays, stab-resistant vests or vest inserts are used by police and security personnel, but also by bus drivers, ambulance officers, and other people who are empirically often attacked on duty. Since stab protection garments are often heavy and thus uncomfortable and not well accepted, whether in the form of chain-mail or metal inserts in protective vests, researchers are striving to find lightweight, drapable alternatives, often based on polymeric materials. These research attempts have recently focused on textile fabrics, mostly with impregnation by shear-thickening fluids (STFs) or ceramic coatings, as well as on lightweight composites. The first studies on 3D printed polymeric objects with tailored shapes, as well as theoretical investigations of the stab-protective effect of different materials, have been published throughout the last years. Here, we discuss different measurement methods, including dynamic and quasistatic methods, and correlations of stab-resistance with other physical properties, before we give an overview of recent developments of stab-resistant polymers, using different materials/material combinations and structures.

Temperature interference in improved FBG pressure sensor for towing tank test

Because of EEDI regulations for ships and SDGs, it is of vital importance to develop ships with good propulsion performance, not only in still water, but also in waves. To predict the propulsion and seakeeping performance in waves, and in particular ship motions and added resistance, various theoretical calculation methods and CFD codes have been developed. To validate these estimation methods, experimental data on details of the flow induced by the ship disturbance are required. To meet this demand, the authors developed an innovative method for measuring and analyzing the spatial pressure distribution over the ship-hull surface using a large number of Fiber Bragg Grating (FBG) pressure sensors. However, pressure measurements with the conventional FBG pressure sensors are largely influenced by the difference in the temperature between water and air, referred to as the temperature interference. To resolve this issue, the authors developed a new FBG pressure sensor that incorporates three improvements and is significantly less influenced by temperature interference. Its performance was confirmed through comparisons with measured pressures obtained using existing strain-type and conventional FBG pressure sensors. Furthermore, the effects of different materials used for manufacturing ship models on the pressure measurement were investigated experimentally in towing tank tests. Finally, an experimental study was conducted to determine which of the three improvements in the latest FBG pressure sensor is essential for reducing the temperature interference.

Characterization of Electronic Transport Properties of Narrow-Band Gap Fe(Se1-xTex)2 Alloys via the Two-Band Model

Environmentally sustainable thermoelectric technologies can be more broadly applied in industries once the performance of thermoelectric materials is improved. Several approaches have been proposed to improve the electronic transport properties of thermoelectric materials. The effects of each approach on the electronic properties can be evaluated by changes in the band parameters. The Single Parabolic Band (SPB) model has been widely used to determine the effect of different materials engineering strategies on band parameters, such as the density-of-states effective mass and deformation potential. However, when the material has a narrow band gap, the Two-Band (TB) model better describes the changes in band parameters, as it includes the bipolar conduction from the minority carrier band. Here, the band parameters of previously reported Fe(Se1-xTex)2 (x/i> = 0, 0.2, 0.6, 0.8, 1) alloys, whose band gap significantly decreases with x/i>, have been estimated using the SPB and TB models. While the x-dependent band parameters obtained via the SPB model varied abruptly with x/i>, all the band parameters estimated by the TB model changed linearly with x/i>. The abruptness observed in the band parameters of the SPB model can be attributed to artifacts reflected in the single band, which occurs when the minority carrier band and band gap change are not included. The bipolar thermal conductivity of Fe(Se1-xTex)2 alloys was also calculated using the TB model, and is understood in terms of changes in the weighted mobility ratio, Hall carrier concentration, and band gap in terms of alloy composition, x/i>.

Numerical Model Calibration and a Parametric Study Based on the Out-Of-Plane Drift Capacity of Stone Masonry Walls

Failure under seismic action generally occurs in the form of out-of-plane collapses of walls before reaching their in-plane strength in historical stone masonry buildings. Consistent finite element (FE) macro modeling has emerged as a need for use in seismic assessments of these walls. This paper presents the numerical model calibration of U-shaped multi-leaf stone masonry wall specimens tested under ambient vibrations and out-of-plane (OOP) load reversals. The uncertain elastic parameters were obtained by manual calibration of the numerical models based on ambient vibration test (AVT) data of the specimens. To obtain nonlinear calibration parameters, static pushover analyses were performed on FE models simulating quasi-static tests. The calibrated numerical models matched well with the experimental results in terms of load–drift response and damage distribution. As a result, the modulus of elasticity and tensile and compressive degrading strength parameters of masonry walls were proposed. A parametric study was conducted to examine the effects of different materials and geometric properties (tensile strength, aspect ratio, slenderness ratio, and geometric scale) on the OOP behavior of stone masonry walls. A quite different strain distribution was obtained in the case of a large aspect ratio, while it was determined that the geometric scale had no effect on the strain distribution. Tensile strength was the dominant parameter affecting the load–drift response of the models. Within the presented work, a practical tool for out-of-plane seismic assessment has been proposed for the structures covered in this paper.

An ultra-broadband solar absorber based on α-GST/Fe metamaterials from visible light to mid-infrared.

In this paper, we proposed an ultra-broadband and high absorption rate absorber based on Fe materials. The proposed absorber consists of a rectangle pillar, two rings, a SiO2 film, a Ge2Sb2Te5(GST) planar cavity, an Fe mirror, and a SiO2 substrate. The average absorption reaches 98.45% in the range of 400-4597 nm. We investigate and analyze the electric field distributions. The analysis of the physical mechanism behind the broadband absorption effect reveals that it is driven by excited surface plasmons. Furthermore, the absorber can maintain high absorption efficiency under a large incident angle. The geometrical symmetric structure possesses polarization insensitivity properties. The proposed structure allows for certain manufacturing errors, which improves the feasibility of the actual manufacture. Then, we investigate the effect of different materials on absorption. Finally, we study the matching degree between the energy absorption spectrum and the standard solar spectrum under AM 1.5. The results reveal that the energy absorption spectrum matches well with the standard solar spectrum under AM 1.5 over the full range of 400 to 6000 nm. In contrast, energy loss can be negligible. The absorber possesses ultra-broadband perfect absorption, a high absorption rate, and a simple structure which is easy to manufacture. It has tremendous application potential in many areas, such as solar energy capture, thermal photovoltaics, terminal imaging, and other optoelectronic devices.

Efeito de diferentes materiais para confecção de prótese parcial removível provisória: um estudo in vitro sobre rugosidade superficial e resistência à fratura

ABSTRACT The use of removable partial dentures is considered a common and inexpensive treatment option to rehabilitate edentulous areas. The aim of this study was to evaluate the effect of different materials for provisional removable partial dentures, an in vitro study on surface roughness and fracture resistance. Thermopolymerizable acrylic resin and thermoplastic resin specimens with dimensions of 10 x 10 x 2 mm (blocks) (n=10) and with dimensions of 65 x 20 x 3 mm (bars) (n=10 were analyzed for their surface roughness (Ra) and three-point flexural strength test. All specimens were subjected to oven aging for 60 days at 37°C±0.5°C in distilled water. The statistical analysis was performed with a significance level of 5%, and the surface roughness data were submitted to the Two-way Anova statistical test (P < 0.05) and the mechanical strength data were subjected to One-way Anova statistical test (P < 0.05). For roughness, the factor resin type (P = 0.000) and the factor aging (P = 0.000) were statically significant, as well as showing interaction (P = 0.228). The Thermopolymerizable acrylic resin had the lowest mean roughness values compared to the thermoplastic resin and showed no statistical difference after aging. The same scenario was repeated for flexural strength values; Thermopolymerizable acrylic resin was statistically superior to thermoplastic resin (P = 0.000). Thermopolymerized acrylic resin showed lower surface roughness values and higher flexural strength values compared to thermoplastic resin.

Thermal percolation network in alumina based thermal conductive polymer

Polymers incorporated with high thermal conductivity fillers have numerous applications in thermal interface materials. Plenty of efforts have been made to improve the thermal conductivity of polymer composite. A possible method is to choose fillers with different morphologies, which can combine the advantages of various fillers. However, owing to the limitations of the effective medium theory as well as lack of researches of thermal percolation, there is still little understanding of the synergistic mechanism of fillers with different morphologies. In order to avoid the coupling effect of different materials, this work uses the same kind of alumina but with different morphologies to prepare different kinds of epoxy composites incorporated with spherical alumina, plate-like alumina and fillers mixed of 1:1 ratio. The thermal conductivity of each sample is measured by the steady state method. With the fitting of the thermal percolation theory, the synergistic effect of plate-like fillers and that of spherical fillers are verified to promote the formation of thermal percolation network. In addition, by observing the microscopic distribution of fillers, we try to explain the mechanism of this synergistic effect.

Enhanced NO2 gas sensing properties of ZnO-PANI composite nanofibers

Composite materials are excellent candidates for gas detection owing to the synergetic effects of different materials within the resulting composite. In this study, ZnO-polyaniline (PANI) composite nanofibers (NFs) were synthesized for NO 2 sensing studies. Initially, the optimal mean diameter of the electrospun zinc acetate-PVA NFs was predicted theoretically using the response surface methodology (RSM). After the optimization studies, the electrospun ZnO NFs were synthesized, and different amounts of PANI (10, 25, and 50 wt %) were added to ZnO NFs to explore the effect of PANI on the NO 2 gas sensing characteristics of the resulting composite. The thermal, structural, chemical, and morphological properties of the synthesized composites were examined. The NO 2 gas sensing response was evaluated at different temperatures. The sensor with 25 wt % PANI showed the best performance to NO 2 gas with good selectivity, exhibiting a high response of 40 to 10 ppm NO 2 gas at 300 °C. Details of the sensing mechanism are presented. The ZnO-PANI composite NFs showed great potential for NO 2 gas sensing.

Influence of monolithic restorative materials on the implant-abutment interface of hybrid abutment crowns: An in vitro investigation.

Purpose This in vitro study aimed to investigate the long-term performance, stability, and fracture mode of monolithic hybrid abutment crowns, and the effect of different materials on the implant-abutment interface (IAI).Methods Eighty monolithic hybrid abutment crowns luted on titanium bases were manufactured from 3Y-TZP zirconia (ZY3), "Gradient Technology" zirconia (ZY35), 5Y-TZP zirconia (ZY5), lithium disilicate ceramic (LDS), zirconia-reinforced lithium silicate ceramic (ZLS), polymer-infiltrated ceramic network (MHY), polymethylmethacrylate (PMA), and 3D-printed hybrid composite (PHC) (n = 10 for each material). Eighty implants (Camlog Progressive-Line, diameter: 3.8 mm) were embedded in accordance with ISO standard 14801, and crowns were mounted. After artificial aging (1.2 × 106 cycles, 50 N, thermocycling), intact specimens were loaded 30° off-axis in a universal testing machine until failure.Results Seven specimens in the PHC group failed during artificial aging, and all the others survived. There were two subgroups based on the one-way analysis of variance and Dunnett's test (P < 0.05) of the mean fracture load values. The first comprised Z3Y, ZY35, Z5Y, and LDS, with mean fracture loads between 499.4 and 529.7 N, while the second included ZLS, MHY, and PMA, with values in the 346.2-416.0 N range. ZY3, ZY35, ZY5, and LDS exhibited irreversible, visible deformations of the implant shoulders with varying dimensions after load-to-fracture tests.Conclusions Crowns made of LDS, ZLS, MHY, and PMA may act as potential stress breakers, and prevent possible deformation at IAIs. Further clinical studies need to assess if these materials also withstand relevant loads in-vivo.

Thermal percolation network in Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; based thermal conductive polymer

Polymers incorporated with high thermal conductivity fillers have numerous applications in thermal interface materials. Plenty of efforts have been made to improve the thermal conductivity of polymer composite. A possible method is to choose fillers with different morphologies, which can combine the advantages of various fillers. However, owing to the limitations of the effective medium theory as well as lack of researches of thermal percolation, there is still little understanding of the synergistic mechanism of fillers with different morphologies. In order to avoid the coupling effect of different materials, this work uses the same kind of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; but with different morphologies to prepare different kinds of epoxy composites incorporated with spherical Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, plate-like Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; and fillers mixed of 1∶1 ratio. The thermal conductivity of each sample is measured by the steady state method. With the fitting of the thermal percolation theory, the synergistic effect of plate-like fillers and that of spherical fillers are verified to promote the formation of thermal percolation network. In addition, by observing the microscopic distribution of fillers, we try to explain the mechanism of this synergistic effect.

Analysis and study of the migration pattern of microplastic particles in saturated porous media pavement

This work aims to establish an analytical and comparative model of pavement stormwater runoff and determine how to solve water pollution in saturated porous media pavements. Heavy metal element particles in the stormwater runoff due to the rainfall will cause inevitable environmental pollution. First, the pavement runoff and materials of saturated porous media are analyzed. Besides, particle migration laws and separation effects of different materials are compared. Based on this, microplastics are selected as the primary material for pavement filling. Then, the adsorption effect of microplastics and the parameters of rainwater infiltration rate and infiltration ratio are analyzed to propose a multi-level ecological integrated treatment system for pavement runoff. Specifically, the environmental resource pollution and saturated porous media materials are analyzed. In addition, the adsorption effect of microplastic particles is analyzed to establish a model to study the selection process of the optimal adsorption material. The main contribution of the research is to analyze the migration process of metal particles in the soil in combination with the internal particle migration rules of plastic granular materials. The research results demonstrate that the rain runoff coefficient gradually increases with the expansion of the permeable area of the pavement. The rain runoff coefficient reaches the maximum value under the pavement of 120 square meters. In addition, a comparative analysis of three street pavements is conducted on the residential street pavement (RSP), commercial street pavement (CSP), and active street pavement (ASP). When comparing the two sets of data, the overall average permeability of the RSP is better than CSP and ASP. The research materials are compared under isothermal conditions. The particle adsorption effect of the same material at 50 °C is significantly better than that at 30 °C. Therefore, it is feasible to resolve the pavement runoff water pollution through technical schemes.

Compression test of multi-scale modified concrete and application of novel damage variable in concrete performance analysis

To change the characteristics of brittle failure and easy cracking of the concrete, a novel method of mixing materials with different scales into concrete to inhibit the generation and development of cracks is proposed. Taking carbon nanotubes (CNTs), calcium carbonate whisker (CCW), polyvinyl alcohol (PVA) fiber, steel fiber and rubber particles as the experimental materials, the multi-scale modified concrete compression test was carried out. According to the test results, the effects of different materials on the mechanical properties of concrete are analyzed, and the optimal content scheme of materials is determined. In view of the damage constitutive and damage variables based on the Weibull distribution cannot comprehensively reveal the mechanical properties and damage state of concrete, the combined damage variable, the damage variable based on energy method and the corresponding damage constitutive model are presented. To synthetically evaluate the mechanical properties of concrete from the perspective of damage, the modified damage variable is proposed considering the influence of concrete compressive strength. The analysis results show that the optimal content of CNTs, CCW, PVA fiber, steel fiber and rubber particles are 0.6%, 6%, 0.075%, 1% and 0%, respectively. The damage variable based on the energy method has a clear damage mechanism and can accurately represent the performance state of concrete. The modified damage variable can significantly distinguish the comprehensive performance of different concretes. In addition, the scanning electron microscope results verified that CNTs, CCW, PVA fiber and steel fiber can inhibit the development of cracks through the bridging effect to change the failure pattern of concrete.

Comparative Effects of Different Materials on Alveolar Preservation

The purpose of this study was to compare different materials' effects on alveolar ridge preservation of postextraction sockets in anterior maxilla. In this prospective, single center, randomized, controlled clinical trial, healthy patients who needed one single anterior maxillary tooth extraction (including bicuspids) were selected. After a minimally traumatic extraction without complications, 44 patients were randomly allocated into 4 groups: 1) natural socket healing (blood clot), 2) xenograft and gingival free graft, 3) dense polytetrafluoroethylene membrane, and 4) platelet rich fibrin plugs. Alveolar ridge height and width loss were evaluated in cone beam computed tomography (CBCT) and in dental casts at 3 moments: 1) preoperative (T1), 2) 7days postoperative (T2), and 3) 120days postoperative (T3). Height and width alveolar ridge loss detected in CBCT and in dental casts were compared among the groups (two-way analysis of variance [ANOVA]; P<.05). Forty patients (24 women and 16 men) ranging from 25 to 70years old (mean of 42years old) participated in this study. Group 2 showed the least alveolar ridge height loss results in CBCT (9.8±1.9% at T3) and dental cast analysis (1.0±0.2mm). Groups 2 (12.7±4.7% at T3) and 3 (15.4±2.7% at T3) showed the least alveolar ridge width loss measured in CBCT compared with groups 1 and 4, but the difference between groups 2 and 3 were not statistically significant (P=.968). Group 3 (0.9±0.2mm) and group 2 (1.0±0.2mm) showed the least width loss compared with groups 1 and 4 in dental cast analysis. Again, the difference between groups 3 and 2 was not statistically significant (P=1.000). In postextraction sockets of the anterior maxilla and bicuspid region, group 2 (xenogenous bone graft with free gingival graft) and group 3 (dense polytetrafluoroethylene) obtained the best results in alveolar preservation, with group 2 being more indicated when the vertical alveolar ridge preservation is mandatory.

Numerical Modelling of Moisture Transport Between Two Enclosures Connected by a Tube

The electronics is protected using plastic or metallic enclosures. Although, the electronics is protected by the enclosures from the surrounding environment, the moisture can still enter the enclosure via gasket, plastic enclosure walls, cable feedthroughs. The moisture existing inside enclosure may condense on PCBA or components due to a temperature changes or different temperature levels and can lead to a moisture-related failures. The temperature in the enclosure is also very dependent on the location and the heating of electronic components. Furthermore, the electronics can be mounted nearby to other heating or cooling components in the complex mechanical systems, such as water pump or water meter. The paper concerns the complex transient heat and mass transfer processes between two connected enclosures with one being warm and another cold. The objective of the paper is to develop an in-house code based on the RC approach for predicting and studying the temperature and moisture behaviour inside two connected enclosures. The developed RC model combines one-dimensional description and lumped analysis for heat and mass transport. The modelling of temperature and moisture response is carried out under non-isothermal B3 STANAG ambient conditions. Moreover, the effect of different material of warm enclosure and the heating are considered.

Shear Strength Prediction Model for RC Exterior Joints Using Gene Expression Programming.

Predictive models were developed to effectively estimate the RC exterior joint’s shear strength using gene expression programming (GEP). Two separate models are proposed for the exterior joints: the first with shear reinforcement and the second without shear reinforcement. Experimental results of the relevant input parameters using 253 tests were extracted from the literature to carry out a knowledge analysis of GEP. The database was further divided into two portions: 152 exterior joint experiments with joint transverse reinforcements and 101 unreinforced joint specimens. Moreover, the effects of different material and geometric factors (usually ignored in the available models) were incorporated into the proposed models. These factors are beam and column geometries, concrete and steel material properties, longitudinal and shear reinforcements, and column axial loads. Statistical analysis and comparisons with previously proposed analytical and empirical models indicate a high degree of accuracy of the proposed models, rendering them ideal for practical application.