Emerging Materials Research

Journal Information
ISSN / EISSN : 2046-0147 / 2046-0155
Published by: Thomas Telford Ltd. (10.1680)
Total articles ≅ 644
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Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 246-256; https://doi.org/10.1680/jemmr.20.00334

Abstract:
The solutions to the increasing problem in the energy demand of the world has been expected from the building sector with consumption of high amount of energy. Producing environmentally friendly and energy efficient blended cements and using materials with high thermal performance in terms of insulation and thermal energy storage in buildings are some of these solutions. Calcined marl at optimum temperature is an alternative pozzolan for blended cement productions. The main purpose of this study is to determine of how the thermal performance and mechanical properties of mortar/concrete will be affected by using calcined marl as alternative pozzolan. For this purpose, the mortars/concretes containing calcined marl blended cements were produced. The calcined marl replacement ratios of blended cements were 0, 10, 30 and 50 wt.%. In the study, the strengths and thermal performances of mortars/concretes containing calcined marl blended cements were determined. The test results were compared among themselves and with each other. According to the test results, it was concluded that thermal performances of the mortars/concretes containing calcined marl blended cements could be improved up to 50% replacement ratio without compromising the strength of considered materials.
Memduh Kurtulmuş, Ezgi Doğan
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 272-277; https://doi.org/10.1680/jemmr.20.00100

Abstract:
Undercutting is a welding defect that appears as a groove in the base metal directly along the edges of the weld metal. It is inevitable in fillet and butt joints if improper welding parameters are used in the operation. It is a discontinuity in the welding which produces stress concentration and lowers the strength of the weld. The stress concentration factor of an undercut is due to reinforcement angle, undercut width, undercut depth and undercut root radius. In this study 20 mm thick mild steel plates were welded by automatic gas metal arc welding with CO2 shielding gas process. Single-V butt joint was obtained after welding. Before welding 30° groove angles were obtained by milling on the longitudinal side of each work piece. Two plates were welded with several passes. After welding the weldment was tested with radiographic NDT process. A defect free weldment was obtained. Then standard tensile test samples were machined from the weldment. A groove was drilled in the heat affected zone, adjacent to the weld metal boundary on every tensile test sample. Each groove resembled an undercut. The length, root radius and depth of grooves were varied. Then samples were broken on a tensile test machine. From the test results the static stress concentration factor of each groove was calculated. The effects of groove geometry on stress concentration factors were determined.
Muammer Şeker, Ibrahim Mutlu, Faruk Emre Aysal, Ismail Sinan Atli, Ibrahim Yavuz, Yelda Akçin Ergün
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 314-320; https://doi.org/10.1680/jemmr.21.00036

Abstract:
In this study, the Taguchi Optimisation technique was utilized with the aim of establishing the composition of an asbestos-free brake pad. As a result of optimization outputs, 18 various compositions were obtained. Produced specimens according to outputs were subjected to Friction Assessment and Screening Tests (FAST) to evaluate their average friction coefficient and friction surface temperature. Assessing the results, the composition of brake pads, which can be used in vehicle brakes, was exhibited. Experimental results also examined by variance analysis to demonstrate effect factors. Furthermore, when the test results are evaluated in terms of friction coefficient, wear rate and temperature of the brake disc, a high coefficient of friction, a moderate wear rate and an acceptable temperature of the brake disc were obtained in Sample 13. Composition of Sample 13 with the highest friction coefficient is: 3 g. brass powder, 9 g. cashew, 9 g. carbon fiber, 9 g. copper dust and 9 g. graphite. In addition, average friction coefficients of brake pads were estimated through Artificial Neural Network (ANN) analysis. In respect to the results, it was discovered that, the generated ANN model promises high ratio estimation capacity.
Shankar Swarup Das, Prasun Chakraborti
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 329-340; https://doi.org/10.1680/jemmr.20.00005

Abstract:
Most of the modern hip joint implants prefer MoP pairs over MoM, where Co-Cr alloy and UHMWPE are commonly used as femoral head and socket respectively. In such implants, the durability of UHMWPE component is not up to the mark due to severe wear. This study presents better tribological performance of a novel bio-polymeric material coded as HD-HA prepared from HDPE and hydroxyapatite. In the first part, wear tests showed the specific wear rates of 4.85 × 10−6 and 5.27 × 10−6 mm3/N-m for HDPE and UHMWPE respectively, whereas it is 3.19 × 10−6 mm3/N-m for HD-HA. Comparison revealed that HD-HA got 60-65% lower wear rate than others. Similarly in the second part, the friction coefficient is found to be 0.23 and 0.11 for UHMWPE and HDPE respectively and 0.06 for HD-HA, which shows 20% to 50% decrease in frictional values. AFM images revealed that rough peaks are 296, 486, and 1100 nm for HD-HA, HDPE, and UHMWPE respectively; whereas the SEM images show fewer loose particles around worn HD-HA surface. This shows HD-HA has smoother surface and based on the overall tribological performance, it should be preferred for acetabular component of hip joint implants.
Berkant Dindar, İnan Ağir, Numan Behlül Bektaş
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 295-299; https://doi.org/10.1680/jemmr.20.00302

Abstract:
In this experimental study, the low velocity impact behavior of aluminum-kevlar laminates (ARALL) was investigated. ARALL composites were prepared in two different configurations as aluminum-kevlar-aluminum (AKA) and kevlar-aluminum-kevlar (KAK). The aluminum alloy used in the preparation of the samples was supplied as 5754 series 2 mm thick plate. Kevlar fabrics were supplied in a weight of 200 gr/m2 and in twill weave type. Laminated composites with kevlar twill fabrics were made through hand lay-up followed by compression molding process. [K]4 composite laminates were obtained by curing kevlar/epoxy laminates under 100°C and 7 bar pressure for 180 min. Then samples of size 100×100 mm were cut from the plates with water jet. The cut specimens were bounded together with two-component adhesive. Impact test device Instron-dynatup 9250 HV was used for impact tests. An energy profil method (EPM), it expresses the impact energy and the corresponding absorbed energy. The increasing impact energy was performed on two configuration of ARALL composites until perforation occurs. Perforation threshold of AKA samples is approximately 70% higher than that of KAK samles.
Yonca Yahşi Çelen
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 307-313; https://doi.org/10.1680/jemmr.21.00043

Abstract:
Radiation has been used in many different fields since its discovery, but using it in medical applications is vital, as it is related to human health. In medical application, many different materials are used for different purposes. Three-dimensional materials are used in phantom technology, and it is important to know the properties of those materials. In this study, the linear attenuation coefficients (LACs; μ, cm−1) and some other related parameters of gamma rays (mean free path, half-value layer, tenth-value layer, effective atomic number (Z eff), electron density (N eff) and equivalent atomic number (Z eq)) were obtained for five different phantom fabrication materials used in medical dosimetry. The calculations were done using the Phy-X/PSD software for gamma energies of 10−3–105 MeV. The obtained LAC results ranged from 0.103 to 0.13 cm−1 for 0.365 MeV, from 0.09 to 0.11 cm−1 for 0.511 MeV and from 0.059 to 0.076 cm−1 for 1.275 MeV.
Iskender Akkurt
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 245-245; https://doi.org/10.1680/jemmr.2021.10.3.245

Berna Kavaz Kındığılı, , Nurettin Öztürk
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 257-264; https://doi.org/10.1680/jemmr.21.00037

Abstract:
Some medieval ceramic finds obtained from Zeytinli Island (Erdek, Turkey) excavations were examined using archeometry techniques. First of all, the color values of the ceramics samples, which were coded and photographed, were determined using the Munsell color system. Morphological structures, chemical and mineralogical contents of the samples were determined by Scanning Electron Microscope/ Energy Dispersive X-ray (SEM/EDX), Wavelength Dispersive X-Ray Fluorescence (WD-XRF) and X-ray Diffraction Method (XRD) analysis. Information was obtained about the matrix, mineral phases, particle sizes, aggregate content, and porosity of ceramics by elemental and color analysis by observations SEM, XRD and XRF measurements. Quartz, Vermiculite, Sepiolite, Illite, Calcite, Hematite mineral phases were found in AD 6th and 7th century ceramic samples (S1, S2, S3) by evaluating the obtained XRD measurements. In addition to other phases, Berlinite, Caracolite and Enstatite phases were observed in AD 13th century ceramics. In the ceramics samples, O, Mg, Al, Si and Ca elements were found in major amounts. SiO2 and Al2O3 compounds were found to have varying concentrations of 67.37-52.95% and 34.39-15.65%, respectively. The elements such as Cu, Sr, Rb, Ni and Mn were observed in trace amounts. Pb element was found in the glazes of the studied ceramics excavated from the Eastern Church. SEM-EDX analysis revealed that the surfaces of well-fired ceramics samples possess a homogeneous structure. According to the results of WD-XRF analysis, it was seen that the chemical compositions and production techniques of Byzantine and Late Roman ceramics were nearly similar.
Azime Yilmaz, Raciye Meral, Mohammad Kabli, Ertan Ermis, Perihan Kubra Akman, Enes Dertli, Osman Taylan, Osman Sagdic, Mustafa Tahsin Yilmaz
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 265-271; https://doi.org/10.1680/jemmr.20.00280

Abstract:
In this work, a nanoemulsion-based delivery system was developed by encapsulation of different concentrations (0.5%, 0.75% and 1% v/v) of oregano essential oil (OEO) within poly-vinyl alcohol. The delivery systems (oregano essential oil loaded nanoemulsion systems, OEO NESs) were characterized in terms of size distribution, zeta potential, thermal, molecular, micro-structural and antifungal properties. The average droplet diameter values were determined in the range of 70–75 nm while zeta potential values were recorded in the range of 3.13-19.90 mV. Increase in the OEO concentration did not affect size distribution of nanoemulsions. Change in the concentrations showed no visible differences in FTIR spectra; however, for the concentrations of 0.5, 0.75 and 1%, endothermic peak temperatures were recorded as 94, 105 and 117°C, respectively. The antifungal activity of NESs against mycelial growth of Aspergillus niger was evaluated, revealing a significant enhancement in the antifungal activity in comparison to that of free OEO. The zone diameter of mycelial growth could be reduced by around 20, 55 and 65% using NESs at the levels of 0.5, 0.75 and 1% v/v, respectively over 6 days of incubation time. The results of this study revealed the stronger antifungal efficiency of OEO by its encapsulation into NESs as compared to that of free OEO.
Cengiz Beyçayırı,
Published: 1 September 2021
Emerging Materials Research, Volume 10, pp 289-294; https://doi.org/10.1680/jemmr.20.00271

Abstract:
Nowadays, autoclaves are widely used for industrial applications such as composite material production, laminated glass production, rubber industry etc. Autoclave is pressurized and heated up according to its special recipes which are prepared by considering technical specification of interlayer material, types and thickness of the glass sheets. During the entire laminated glass production period, gasket on the autoclave door provides sealing and it must not damage the steady air circulation inside of the autoclave. In the present study, the sealing of glass lamination autoclave was investigated numerically. In order to perform finite element analysis, a simplified finite element model has been created by considering both gaps between autoclave door and its housing and also, geometry of gasket. In general, hyper-elastic based gasket materials are used for glass laminating autoclaves. Mooney-Rivlin hyper-elastic material model was used for this study. In this study, 9 different gasket geometries were designed and FEM analysis of the gaskets were carried out by using Ansys Workbench. FEM analyses were performed at 13 bar for operating pressure. Results have been compared in terms of deformation of the gaskets, von Misses equivalent stress. The most suitable gasket geometry has been determined according to the simulation and FEA results.
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