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KARAHAN, MEHMET

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KARAHAN

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MEHMET

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Now showing 1 - 10 of 12
  • Publication
    Influence of chemical treatments and nanocellulose spray coating on the mechanical, low velocity impact and compression after impact performance of nonwoven jute composites
    (Taylor, 2019-04-11) Jabbar, Abdul; Hussain, Jown; Basit, Abdul; Naeem, M. Salman; Javaid, M. Usman; Karahan, Mehmet; Nazir, Ahsan; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021
    This paper reports the preparation and characterization of nonwoven jute composites. The untreated and chemically treated waste jute fibers were used to prepare needlepunched nonwoven fabrics. The treated waste jute fibers were also used to extract nanocellulose by pulverization, followed by acid hydrolysis. The prepared 2 wt% suspension of nanocellulose was spray coated over chemically treated nonwoven jute fabric. Afterward, the composites were prepared by compression molding technique. The surface morphologies of treated jute fibers and nanocellulose were characterized by scanning electron microscopy. The crystallinity of chemically treated jute fibers and nanocellulose was measured by X-ray diffraction. The effect of chemical treatments and nanocellulose spray coating over nonwoven jute reinforcement on the tensile, flexural, drop weight impact, and compression after impact properties of prepared composites has been investigated. The results revealed the improvement in mechanical properties after chemical treatments and nanocellulose coating. The overall better results were shown by composite sample prepared from chemically treated followed by nanocellulose sprayed jute nonwoven reinforcement.
  • Publication
    Multi-response optimisation for the development of an activated carbon web as interlining for higher electrical conductivity and emi shielding using grey relational analysis
    (Inst Chemical Fibres, 2021-01-01) Naeem, M. Salman; Ahmad, Naseer; Javed, Zafar; Jabbar, Abdul; Rehman, Ateeq Ur; Zubair, Muhammad; Gilani, Syed Qummer Zia; Ahmad, Zuhaib; Karahan, Mehmet; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; AAK-4298-2021
    This paper presents a simple and novel method of producing an activated carbon (AC) non-woven web from acrylic waste derived fin discarded bathmats converted into a nonwoven web by a caidingand needle punching machine. After stabilisation at lower temperature, carbonisation of the stabilised web was performed in a muffle furnace. The carbonisation temperature, the holding time of the activated carbon web at the final temperature, the heating rate to reach the final carbonisation temperature and the number of steps adopted for developing the carbon web were optimised using the grey relational analysis (GRA) approach to get optimum responses of the surface area of the web, electrical conductivity and electromagnetic shielding. The results demonstrated a large improvement in electrical conductivity as surface resistivity decreasedfrom 134.21 Omega.mm to 0.28 Omega.mm, and the corresponding electromagnetic shielding increased to 82.63 dB when the temperature of the carbonisation, the holding time and number of steps were increased. The surface area in the AC web was increased from 73 m(2)g(-1) to 210 m(2)g(-1) with an increase in the carbonisation temperature, the holding time and number of steps to reach thefinal temperature. The optimisation technique used in this work could be successfully used in cost and error reduction while producing an AC web. The optimised AC web was characterised by Brunauer; Emmett and Teller (BET), X-ray diffraction characterisation and elemental analysis (EDX) in order to determine changes in its structure, surface area, degree of crystallinity, inter-layer spacing and proportion of different elements. The AC web developed can be effectively employed as interlining in apparels because of its flexibility and eco-friendly electromagnetic shielding, as it works on the principle of the absorption, reflections and internal reflections of electromagnetic radiations.
  • Publication
    Investigation of impact properties of para-aramid composites made with a thermoplastic-thermoset blend
    (Sage Publications, 2021-06-01) Khan, Muhammad Imran; Umair, Muhammad; Hussain, Rizwan; Karahan, Mehmet; Nawab, Yasir; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021
    During impact, thermoset composites show brittle behaviour, whereas thermoplastic composites show a relatively ductile behaviour with higher absorption of impact energy. The research on the investigation of the impact performance of composites with thermoplastic resin and/or with a blend of thermoplastic and thermoset resins found rare. In the present study, both thermoset (phenolic, vinyl ester) and thermoplastic (Polyvinyl butyral - PVB) matrices were used with Para-aramid reinforcement for the development of five-layered composite samples. Drop weight impact, Charpy impact, flexural (three-point), and hardness tests were conducted to assess the performance of the composite samples. The developed thermoplastic composites showed superior impact properties as compared to thermoset composites except for out-of-plane deformation (trauma). This deformation was reduced using a blend of PVB and Phenolic. The composite made with blend absorbs 8-9% more energy as compared to Phenolic composites with almost the same value of trauma. Overall, damage area is also lesser in the case of composite made using a blend. The experimental results are validated by one-way ANOVA (Tukey) statistical analysis.
  • Publication
    Geometrical model to determine sewing thread consumption for stitch class 406
    (Inst Chemical Fibres, 2021-11-01) Rehman, Ateeq ur; Rasheed, Abher; Javed, Zafar; Naeem, M. Salman; Ramzan, Babar; Karahan, Mehmet; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksek Okulu.; AAK-4298-2021
    This study aimed at developing a geometrical model for predicting the sewing thread consumption of stitch class 406. Stitch class 400 is a multi-thread chain stitch which consumes a less amount of thread as compared with stitch class 500 but more thread as compared with stitch class 300. Sewing thread calculation plays a significant role in determining the exact amount of thread for completing a garment and predicting the right quantity of thread for bulk production. The geometrical model developed was used for predicting sewing thread consumption by using different factors like stitch density (8 and 12 SPI), material thickness (2, 4 and 6 layers of fabric), and type of material (denim, knitted and fleece). The model was validated with a total of 18 samples sewn with different kinds of fabric, SPI, and material thickness. It was concluded that the model could predict sewing thread consumption with more than 97.18% accuracy.
  • Publication
    Low velocity impact behaviour of aramid and uhmwpe composites
    (Inst Chemical Fibres, 2015-05-01) Karahan, Mehmet; Yıldırım, Kenan; KARAHAN, MEHMET; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu; 0000-0003-3915-5598; AAK-4298-2021
    The most popular method to produce composites for ballistic applications is to use aramid and ultra high molecular weight polyethylene (UHMWPE) fibers as reinforcement materials in different matrices. The composite materials used in this type of application, especially those used as armoring materials for explosions, are subjected to a very high level of energy. In this study, the effect of the reinforcement material type and cross-plied condition of reinforcement were examined using high-level impact tests. The impact tests were performed at low speed but high energy, and thus the behaviour of the composite materials that were exposed to high-level impact energy could be examined. According to the results, the UD aramid composite produced the best results with respect to high-level impact tests. In addition, mass optimisation could be achieved without the loss of the high-level impact energy by preparing a hybrid composite with UD UHMWPE and UD aramid fibers.
  • Publication
    Geometrical analysis of 3d integrated woven fabric reinforced core sandwich composites
    (Inst Chemical Fibres, 2019-01-01) Jabbar, Abdul; Zubair, Muhammad; Karahan, Mehmet; KARAHAN, MEHMET; Karahan, Nevin; KARAHAN, NEVİN; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; 0000-0001-6900-4147; 0000-0003-3915-5598; 0000-0003-2362-517X; JQW-3721-2023; AAK-4298-2021; JON-7556-2023; O-2447-2015
    The variability of the internal geometry parameters, such as the waviness of yarns, cross sections of yarns and local fibre volume fraction of 3-dimensional (3D) integrated woven core sandwich composites affects their mechanical properties. The objective of this study was to define the geometrical and structural parameters of 3D integrated woven core sandwich composites, including the fold ratio of pile threads, the fabric areal weight and the fib re volume fraction by changing the core thickness of 3D sandwich core fabric. 3D fabrics with different core thicknesses were used for reinforcement. It was confirmed that the pile fold ratio, slope angle and pile length increase with an increase in the core thickness of the fabric. The difference between the calculated and experimental areal weights of fabrics was in the range of 5-13%. A novel approach was also presented to define the fibre volume fraction of 3D woven core sandwich composites.
  • Publication
    Low velocity impact behaviour of aramid and uhmwpe composites
    (Inst Chemical Fibres, 2015-05-01) Karahan, Mehmet; Yıldırım, Kenan; KARAHAN, MEHMET; Uludağ Üniversitesi/Mühendislik-Mimarlık Fakültesi/Tekstil Mühendisliği Bölümü; 0000-0003-3915-5598; AAK-4298-2021
    The most popular method to produce composites for ballistic applications is to use aramid and ultra high molecular weight polyethylene (UHMWPE) fibers as reinforcement materials in different matrices. The composite materials used in this type of application, especially those used as armoring materials for explosions, are subjected to a very high level of energy. In this study, the effect of the reinforcement material type and cross-plied condition of reinforcement were examined using high-level impact tests. The impact tests were performed at low speed but high energy, and thus the behaviour of the composite materials that were exposed to high-level impact energy could be examined. According to the results, the UD aramid composite produced the best results with respect to high-level impact tests. In addition, mass optimisation could be achieved without the loss of the high-level impact energy by preparing a hybrid composite with UD UHMWPE and UD aramid fibers.
  • Publication
    A review of cellulosic natural fibers' properties and their suitability as reinforcing materials for composite panels and applications
    (Sage Publications Inc, 2023-02-03) Arı, Ali; Ahmed, Hasabo Abdelbagi Mohamed; Babiker, Omsalma; Dehset, Ramazan Muhammed Ahmed; Karahan, Mehmet; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Eğitim Fakültesi.; 0000-0003-3915-5598; AAK-4298-2021
    There has been much effort to provide eco-friendly and biodegradable materials for the next generation of composite products owing to global environmental concerns and increased awareness of renewable green resources. Increased use of natural materials in composites has led to a reduction in greenhouse gas emissions and the carbon footprint of composites. In addition to the benefits obtained from green materials, there are some challenges in working with them, such as poor compatibility between the reinforcing natural fiber and matrix and the relatively high moisture absorption of natural fibers. Green composites can be a suitable alternative for petroleum-based materials. However, before this can be accomplished, a number of issues need to be addressed, including poor interfacial adhesion between the matrix and natural fibers, moisture absorption, poor fire resistance, low impact strength, and less durability. Several researchers have studied the properties of natural fiber composites. These investigations have resulted in developing several procedures for modifying natural fibers and resins. To address the increasing demand to use eco-friendly materials in different applications, an up-to-date review of natural fiber and resin types and sources, modification, and processing techniques, physical and mechanical behaviors, applications, life-cycle assessment, and other properties of green composites is required to provide a better understanding of the behavior of green composites.
  • Publication
    Comparison of the mechanical properties of chopped glass, carbon, and aramid fiber reinforced polypropylene
    (Sage Publications, 2022-05-01) Arı, Ali; Bayram, Ali; Karahan, Mehmet; Karagöz, Secgin; BAYRAM, ALİ; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; Bursa Uludağ Üniversitesi/Meslek Yüksekokulu/Tekstil Bölümü; 0000-0003-3915-5598; AAK-4298-2021; GZC-1297-2022
    In this work, a comparative assessment of the mechanical properties of chopped glass-carbon-aramid fiber reinforced polypropylene (PP) composites was carried out. Reinforcement and matrix materials were mixed with the extrusion method, and then composite materials were produced in the form of plates with the press molding technique. The composites' tensile, 3-point bending, and drop weight tests were carried out and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). The tests' results indicate that the mechanical properties increase significantly in the presence of fiber. On the other hand, it is observed that the effect in percentage decreases as the fiber content increases. Moreover, It was observed that some of the fiber materials were pulled out from the matrix as a result of stress. ANOVA analysis using S/N values, and F-Test were performed to observe the effectiveness of each test factor (fiber type, and fiber additive content) on the test results. Finally, an optimization study was carried out to obtain the mathematical expression by fitting the experimental data.
  • Publication
    Optimization of knitted fabrics for better thermo-physiological comfort by using taguchi-based principal component analysis
    (Univ Ljubljana, 2023-02-06) Kazmi, Kashaf; Javed, Zafar; Salman, Muhammad; Iftikhar, Fatima; Ahmed, Naseer; Naeem, Jawad; Jabbar, Abdul; Naeem, M. Salman; Karahan, Mehmet; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; AAK-4298-2021
    The water, air permeability and thermal resistance of fabrics are important attributes that have a significant impact on the thermal comfort properties of sportswear fabrics in different environmental conditions. In this work, terry and fleece fabrics were developed by varying the fibre content and mass per unit area of fabrics. Moreover, the thermo-physical properties of the developed fabrics, including air permeability, water vapor permeability and thermal resistance, were analysed before and after washing. The multi-response optimization of the thermal comfort properties of knitted fabrics was performed using principal component analysis (PCA) and the Taguchi signal-to-noise ratio (PCA-S/N ratio) to achieve optimal properties. It was determined that the selected parameters (fabric type, finishing, fibre content and fabric mass per unit area) had a significant effect on the thermal comfort properties of knitted fabrics. The PCA analysis showed that 100% cotton terry fabric before washing with an aerial weight of 220 g/m(2) had higher air and water vapor permeability value, but a lower thermal resistance value.