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All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Cupric oxide were prepared by sol-gel technique and deposited onto glass substrates as thin films using spin coating method. The aim of this research was to study the effects of different spin coating speeds and solution concentrations of cupric oxide thin films on the structural, optical, electrical and physical properties of thin films. Thin films were deposited with concentration variation of the solution ranging from 0.5 M-1 M and speed variation from 1200 rpm-2400 rpm. X-ray diffraction (XRD) and UV-Vis spectrophotometer were used to characterize the structural and optical properties of the deposited films, respectively. The as-synthesized CuO thin films were also characterized using SEM. The dc electrical properties were characterized using nano-electrometer. Based on the results obtained, it was found that the electrical resistivity of the cupric oxide thin films increases as spin coating speeds increase. The optical band gap values of CuO thin films for concentration variation were found 1.47-1.27 eV and for speed variations, it was observed 1.45-1.95 eV. Decreased values of the optical energy gap were observed with increasing concentration while reverse effect was found with increasing speed of spin coating.

Solar cells hold a promising prospect in the foreseeable future. Presently cuprous oxides (Cu₂O), due to their excellent photovoltaic properties, are being considered as p-type semiconductor materials for solar cell. This work aims at electroless deposition of p-type Cu₂O thin film on copper substrate and studying its various properties through characterizations. A bath containing varying amounts of CuCl₂.2H₂0, CoCl₂.6H₂0, NaH₂PO₂.6H₂0 and KNaTar.4H₂O (Potassium sodium tartrate tetrahydrate) was used for the process. NaOH pellets were used in order to get the desired pH level ranging from 11 to 14. The bath temperature was varied between 30°C to 70°C. The deposited films were characterized by Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscopy (EDS), X-ray diffractometer (XRD) and UV spectroscopy. It was observed that thin films were deposited at different conditions and uniform deposition of Cu₂O thin film was visible at pH 14. The coating thickness was found to be in the range of 0.48 to 4.6 μm. The bandgap for the deposited Cu₂O was found to be in the range of 1.3-1.4 eV. Some variation in results at different pH were observed and the reasons were identified.

Importance of the activation site density on final encapsulation of multi-walled carbon nanotubes (MWCNTs) with copper was investigated in this study. MWCNTs, sensitized with tin and activated with silver, were used as precursors to prepare copper-decorated nanotubes. The effect of activation bath pH was found to be critical to control the density of silver-activation sites and to produce uniform encapsulation of carbon nanotubes (CNTs) with copper in the subsequent electroless deposition method. The morphology of the copper decorated nanotubes was studied using Field Emission Gun Scanning Electron Microscope (FEG SEM) and Energy Dispersive Spectroscopy (EDS).

Jute fiber reinforced composites is an emerging area in composite science because of their low cost, low density and high specific properties. These composites are biodegradable and non-abrasive. In this research work, 10 and 15 wt% raw jute fiber reinforced polyester composite were made in hand lay-up method. Then each type of composite was again fabricated but this time, different levels of post-stress of 2.5, 5 and 10 kPa were applied to observe their effect. Later on, the developed composites were subjected to the tensile test. All composites had higher tensile properties (tensile strength and tensile modulus) than pure polyester. Tensile properties were observed to increase with increasing post-stress for same weight percentage of jute fiber.

Jute fiber is used as a reinforcement material for its availability, lightweight, non-toxicity, biodegradability, low cost, renewable source and moderate mechanical properties. In addition, jute fiber has longer continuous length. In this study, 10 and 15 wt% jute fiber reinforced polymer matrix composites were fabricated by hand lay-up method using polyester resin. The jute composites were developed with and without compression stress. To understand the effects of compression stress levels 2.5, 5 and 10 kPa were used. The jute fibers used here were in untreated condition (raw jute fiber). Developed composites were then characterized by three-point flexural test. Experimental results revealed that compression stress significantly enhanced the flexural properties (flexural strength and flexural modulus) of the composites. In this regard, 15 wt% jute fiber reinforced composite showed greater flexural properties.

The term hybrid composite refers to the composite containing more than one type of fiber material as reinforcing fillers. It has become attractive structural material due to the ability of providing better combination of properties as compared to single fiber composite. In present research, banana and betel nut fiber reinforced polypropylene composites were prepared by hot pressing technique. Raw banana and betel nut fiber were chemically treated with sodium hydroxide to increase adhesion of those fibers with polypropylene. Both raw and alkali treated fibers at 15 wt% were utilized during composite preparation. Banana and betel nut fiber ratios were varied at 1:1, 3:1 and 1:3. Scanning electron microscopic and thermogravimetric analysis, mechanical (tensile, flexural, impact and hardness) and water absorption tests of prepared composites were subsequently conducted. According to microscopic analysis, composites containing treated banana and betel nut fiber at 3:1 ratio had the best adhesion between the fibers and matrix. Polypropylene composites reinforced with banana and betel nut fiber 3:1 ratio had highest tensile and flexural properties, while composites reinforced with banana and betel nut fiber 1:3 ratio showed highest impact properties. According to water absorption test, higher banana fiber containing composite had higher water absorption as compared to higher betel nut fiber containing composite. Polypropylene composites reinforced with equal amount of banana and betel nut fiber had highest thermal stability among all prepared composites. Sodium hydroxide treatment of fibers increased flexural and hardness properties of composites as compared to raw fiber composites. On the other hand, opposite trend was observed in case of tensile, impact and water absorption properties.

In present research, mechanical properties of silk-glass fiber reinforced hybrid polypropylene composite were evaluated. Composites were prepared using hot press machine at three levels of fiber loading (5, 10 and 15 wt.%). Tensile, flexural, impact and hardness tests were conducted for the characterization of the composites. Tensile strength decreased, whereas flexural strength increased with fiber loading. On the other hand, Young's modulus, flexural modulus and hardness increased up to 10 wt.% fiber loading. Impact strength remained unchanged with fiber loading. Based on fiber loading, 10 wt.% fiber reinforced composites had the optimum set of mechanical properties. For 10 wt.% fiber loaded composite, silk and glass fiber ratio was also varied at 1:1, 3:1 and 1:3. On the basis of fiber loading and ratio, the composite containing 10 wt.% fiber at 1:1ratio of silk and glass showed the best set of mechanical properties.

Graphene and its derivatives, owing to their superior properties have been being used as reinforcement to improve the properties of polymer matrix. In this work, the influence of Reduced Graphene Oxide (RGO) on the properties of Poly Vinyl Alcohol (PVA) has been studied. RGO was synthesized from graphite powder starting with synthesis of Graphene Oxide (GO) by Modified Hummer's Method followed by the reduction of GO with Hydrazine Hydrate. Synthesized RGO was characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). PVA composites with different RGO loading were fabricated by simple solution mixing method. The fabricated composites were characterized by Optical Microscopy, XRD, UV-Visible Spectroscopy, Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and Shore hardness test. The reports from those tests have ensured that after incorporating RGO in PVA matrix, band gap energy was decreased, crystallinity and shore hardness were increased and thermal stability was improved up to a certain level of RGO loading.

Magnesium and its alloys are potential candidate in the transportation sector being the lightest structural material. In this work, effects of calcium addition in a as-cast and homogenised AZ61 (aluminium 6 wt.% and zinc 1 wt.%) magnesium alloy was investigated. Phase prediction based on thermodynamic data indicated that formation of Al₂Ca phase could effectively suppress the formation of Mg₁₇Al₁₂ phase. This Al₂Ca phase was present in the microstructure in almost the actual stoichiometry, as found in SEM EDS. The formation of this phase was also confirmed by DSC. During hot compression, recrystallization took place irrespective of temperature. However, at elevated temperature, slight grain growth of the refined grains was evident. This was due to the thermal energy from the test temperature. Nevertheless, such grain growth was not very effective due to the presence of nano-size Al₂Ca phase, which provided pinning effect by positioning at the grain boundaries.

Magnesium alloys have received a considerable research focus in transportation sector due to its lightness and environmental legislation to reduce green-house effects. In this work, a magnesium alloy containing aluminium, zinc and tin as major alloying addition was studied. After casting, the alloy was homogenised and hot-rolled at 400 °C. This temperature was sufficient to promote extensive dynamic recrystallization as evident from microstructure. Texture was obtained as pole figures. The pole figures clearly revealed basal texture which also ensures the rotating of the crystals along the rolling directions. Aging of the alloy was conducted up to 30 hr at 170 °C. Surprisingly, this T5 treatment showed increased mechanical properties with time. This behaviour was studied in scanning electron microscopy. It was found that spherical-shaped Mg₂Sn particles were precipitated as both nano-size particles and micron-size particles. These particles were responsible to age-strengthening of the alloy. Since particle stimulated nucleation is size dependent phenomenon, only Mg₁₇Al₁₂ phase effectively participated in grain refining. Aging response was entirely due to the presence and coarsening of Mg₂Sn particles.

This paper explores the possibility of developing an Al-Mg₂Si-Mg-Zn based sand cast alloy having improved mechanical properties. The effect of Zn and free Mg after combining with Si to form Mg₂Si on microstructure and mechanical properties was investigated under as-cast condition. Eight different alloys were prepared by varying Mg(4.15 – 12.0 wt.%) and Zn(2.58 – 6.22 wt.%) contents and 0.2 proof strength, tensile strength, elongation at failure and hardness were measured under as-cast condition. The microstructural investigation was conducted by optical microscopy and all alloys were found to contained α-Al, Al-Mg₂Sieutectic and Mg₂Siphases. The addition of Mg generally improves the proof strength and decreases the elongation, while the tensile strength shows a peak for alloys having Mg contents between the range 3 – 6 wt.%. Addition of Zn content also has the similar effect in improving strength and hardness and decreasing ductility. Comparing all alloys, alloy 3having 5.41wt.%Mg, 1.85%Si and 5.45%Zn has the best combination of properties.

To improve the vacancy related defects associated with pure BiFeO₃ (BFO) different Ba-Mn co-doped samples (Bi1_-xBa_xFe_yMn_yO₃; x = 0.1; y = 0.0, 0.05, 0.1, 0.15) were prepared from sol-gel method. The influence of co-doping on structural, magnetic and optical properties of BiFeO₃ has been studied in different experimental conditions. Particle size and magnetic properties were measured from SEM and VSM analysis respectively. Again band gap was calculated from UV analysis. The co-doped samples showed reduced particles size as well as better surface morphology. M-H loops suggest that the presence of Mn²⁺ increased ferromagnetic quantity at some levels. Still room temperature occurrence of ferromagnetism obtained from M-H loops of all samples showed weak ferromagnetic behaviour. In addition the incorporation of Ba²⁺ at Bi³⁺ site and Mn²⁺ at Fe³⁺ site decreased the band gap which was evidenced by increased optical property.

A very fast auto-combustion reaction technique was applied for the preparation of a series of Li_xCu_0.12Mn_{0.88 - 2x}Fe_{2 + x}O₄ ferrites in a wide range of composition (with x = 0.00, 0.10, 0.20, 0.30, 0.40 and 0.44). Disc and toroid shaped samples were prepared and sintered at various temperatures, in namely, 1200, 1250, 1300 °C in air for 1 hour. The spinel structure of all these samples were confirmed by X-ray diffraction and grain size estimation obtained from the optical microscope. It has been found that the lattice constant increases linearly with increasing Li contents. The grain size increases with increasing Li content and sintering temperature in Li_xCu_0.12Mn_{0.88 - 2x}Fe_{2 + x}O₄. The magnetic properties of these compositions are characterized by high frequency (10 KHz-120 MHz) magnetic permeability measurements. The real part of initial permeability, µ_i^/ increases with increasing Li content. It has also been observed that μ_i^/ for each sample increases with sintering temperatures because of uniform grain growth. The relative quality factor, Q increases with increasing sintering temperature. Among all the samples, the highest value of Q-factor has been observed for x = 0.40 sintered at 1300 °C.

In this contribution, Sr and Mn co-doped Bi_0.90Sr_0.10Fe_xMn_{1 − x}O₃ (X = 0, 5%, 10%, 15%) nanoparticles were prepared by sol-gel (chemical route) method to observe the dominance of co-substitution on their grain size, morphology, UV-vis absorbance and magnetic properties. Co-substitution of Sr and Mn in BiFeO₃, leads to structural transformation from rhombohedral (R3c) to orthorhombic (Pn2₁a). Field emission scanning electron microscope reveals that upon Mn doping nanoparticles become finer. The M-H loops depict that at 15 mol. % Mn doping the saturation magnetization (Ms) is enhanced significantly. Moreover, the synthesized nanoparticles absorb visible light and their band gaps reduce substantially.

Biomorphic alumina ceramic with a long, large and oriented growth of alpha alumina grains suitable for the devices such as prosthetic implants, dental implant and control drug release etc. Ultralight porous alumina was synthesized from a carbonaceous preform derived from bamboo using biotemplating technique. Carbonaceous preform (C-preform) of bamboo precursor was prepared by controlled thermal processing in a muffle furnace for pore formation. Al₂O₃ was inserted into C-preforms by sol-gel method applying repeated infiltration of low viscous Al₂O₃-sol and then dried and sintered at 1500°C in air atmosphere resulting of an ultra-light monophasic Al₂O₃ ceramics with replication of the pore structure of the bamboo C-preforms. The microstructure of porous Al₂O₃ was characterized by scanning electron microscopy (SEM). Open hierarchical porous structures surrounded by alumina struts web with nominal porosity of 80% inside the biomaterial are visualized which lacking of interconnectivity and low strength.

Gd and Cr co-doped Bi_0.9Gd_0.1Fe_{(1 − x)}Cr_xO₃ (x = 0 − 0.08) nanoparticles were synthesized via sol-gel method. Precursor salts of bismuth, iron, gadolinium and chromium were used as starting raw materials. Obtained nanoparticles were annealed at various temperatures between 400 − 700 °C. Optimal properties were found to display at 600 °C. X-ray diffraction (XRD) patterns revealed that the partial substitution of Bi³⁺ by Gd ions and Fe³⁺ by Cr ions in BiFeO₃ (BFO) resulted in evolution of phase transition from rhombohedral to orthorhombic structure. The average crystallite size was found to vary from 16 to 68 nm depending on doping level. The field emission scanning electron micrographs demonstrated a distinct morphology of spherical and nano-sized particles. Ferroelectric measurements showed a substantial improvement in polarization in doped BFO under an applied field of ± 30 kV/cm. Magnetic properties measured at room temperature showed enhanced ferromagnetic characteristics with increasing doping level of Cr up to 6 % (at.) compared to that of un-doped BFO. An asymmetric shift both in the field and magnetization axes of M-H loops was also observed.

Functional magnetic materials of composition Ni_{1 − x}Co_xFe₂O₄ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) were prepared using NiFe₂O₄ (soft) and CoFe₂O₄ (semi-hard) nanomaterials following solid state synthesis technique. Magnetic properties of synthesized samples were studied employing XRD, FESEM, VSM and DSC techniques. Curie temperature, T_c of all the samples were determined from the temperature dependence of permeability and compared with the peak temperature of DSC thermograph. T_c is found to decrease with increasing CoFe₂O₄ substitution which has been ascribed due to weakening of J_AB super-exchange interaction between tetrahedral and octahedral sites. The detail hysteresis parameters such as M_s, M_r, H_c have been determined from M-H loop measured at 80, 200 and 300K. Saturation magnetization, M_s measured at 80K was found much higher compared with data at 300K. M_s is found to increase with decreasing temperature and attained a maximum value corresponding to CoFe₂O₄ at any measurement temperature which may be attributed to higher magnetic moment of CoFe₂O₄ compared with NiFe₂O_4. A gradual magnetic hardening was observed to increase with increasing CoFe₂O₄ content with a maximum value of H_c at x = 0.8. Initial permeability as a function of frequency has been measured by an impedance analyzer. Phase transition temperature determined from DSC measurements and temperature dependence of initial permeability was found to display a good correlation. In addition, magnetic hardening of soft NiFe₂O₄ with increasing amount of CoFe₂O₄ substitution is also explained based on the existing theories of magnetism.

The research focuses on the utilization of hard rock dust for formulating ceramic glazes. The rock dust was collected from Maddhapara Granite Mining area, Dinajpur, Bangladesh. Chemical compositions of raw materials were analyzed by XRF. Rock dust is characterized by high SiO₂, K₂O, and Na₂O with low content of ferromagnesian element. For Rock dust minor amounts of components may be presents, which will mostly affect the color of the fired product (Fe₂O₃, MnO, TiO₂, Cr₂O₃).Others (MgO, K₂O, Na₂O) will act as fluxes and may have a strong effect during sintering. Ceramic glazes containing up to 30 wt% rock dust were prepared. The glaze slurries were applied onto ceramic tiles, which were sintered at 1050 to 1100°C with slow and rapid heating rate. Different glaze mixtures containing rock dust were prepared and analyzed for micro hardness and glossiness. Microstructures of the ceramic glaze were observed by FESEM (Field emission scanning electron microscopy). The results indicated that the properties of ceramic glaze were better sintering with slow heating rate and confirmed that dust can be used in glaze formulation. Therefore utilization of hard rock dust in glaze formulation may be new possibility for recycling and conserving natural resources.

Over the years, Al–7Si–Mg alloys are used because of their excellent castability, high weight-to-strength ratio, good corrosion resistance and good weldability. In this paper, the fatigue behaviour of Al–7Si–0.3Mg alloys, conforming to A356, has been studied. Specimens of this material were fatigue tested in both the as cast condition, solution treated and aged conditions. The fatigue test was conducted using 3-point fatigue bending setup with the principle of low cycle fatigue failure mechanism. Overaging is found to affect the fatigue behaviour of Al-7Si-0.3Mg alloys. The fatigue properties of as cast alloys showed a three times increase upon solution treatment. Peak ageing condition further improves the fatigue value. Exposure to severe overageing conditions reduced the fatigue properties somewhat from that of the peak values but still maintained higher value than the as-cast conditions, which is constant irrespective of the overageing condition. The improved fatigue properties of heat treated samples can be generally attributed to the spheroidisation of acicular silicon particles.

AZ91, AZ91-0.5B and AZ91-1.0B magnesium alloys are produced in an inert atmosphere to investigate the influence of B on microstructure and properties of AZ91 alloy. Microstructural study is carried out using optical microscopy. Microhardness measurements are conducted by Vickers hardness tester. Using a pin-on-disk type apparatus, wear tests are conducted under dry sliding condition to assess the beneficial effect of boron on the wear properties of AZ91 alloy in relation to the resulted hardness and microstructures. The worn surface and wear particles morphology are also investigated. It is observed from microstructural investigation that the grains become finer with the addition of boron. The hardness is also found to increase with the addition of boron in AZ91 alloy, however maximum hardness is achieved with the addition 0.5 % B addition. The wear resistance is found to be better in the boron added alloy and maximum resistance is found with the addition of 0.5 % B. Wear mechanisms are also investigated.

Plain concrete is very brittle and weak. It cannot withstand sudden shock, cyclic load and high level of tensile stress. So, concrete is reinforced by various types of structural steels. To reduce the overall weight of the RCC structures, worldwide practice is to use high strength structural steels along with high strength concrete. In this research work low strength high ductility (300 grade) and high strength moderate ductility (500 grade) locally produced steel bars of 20mm diameter were used. They were then characterized by means of chemical composition, microstructure, size and distribution of inclusion particles, tensile and fatigue tests. The fracture surfaces of the failed fatigue samples were observed under optical and scanning electron microscopes. After detail investigation, experimental results suggest that compared to ductility, cleanliness of the structural steel bars are much more important for better fatigue life of the RCC structures.

This study aims to develop a reliable finite element analysis procedure to model the complete fracture of ductile specimens using the progressive degradation of the material stiffness algorithm under tensile load. The ductile specimen in this study is an aluminum alloy. The progressive failure algorithm used here is based on the assumption that the material behaves like a stable progressively fracturing solid. The stiffness reduction is carried out at the reduced integration gauss points of the finite element mesh depending on the mode of failure. A number of material properties are necessary for such simulation to carry out and experimentation of the metal are needed to evaluate these properties. The actual tensile tests data are applied to the finite element simulation. The verified simulation method has a great importance in practical design of structures and metals. A renowned finite element analysis software ABAQUS is used in this study.

A leaf spring is a simple form of spring commonly used for the suspension system in heavy duty vehicles which is originally called laminated or carriage spring. It performs the isolation task in transferring the vibration due to road irregularities to the passenger's body or goods transported on it. The advantage of leaf spring over helical spring is that the ends of the spring have been guided along a definite path as it deflect to act as a structural member in addition to an energy absorbing device. Increasing competition and innovations in the automobile sector, tends to modify the existing products with new or advanced material products. To improve the performance of the suspension system, many modifications have been taken place overtime but the recent innovations imply parabolic leaf spring and application of composite materials, as the composite materials have high strength-to-weight ratio compared to the conventional steels. The present work attempts to analyze the comparison between the conventional steel (AISI1030) leaf spring and the composite (Carbon/Epoxy) leaf spring with respect to static and fatigue analysis. Here static analysis determines the safe stress, deformation and corresponding pay load and also studies the behavior of structures under practical conditions. The research also focuses on fatigue analysis to determine its life cycle and also to observe its fatigue failure characteristics. The model of the leaf spring has been carried out into the CAD software. The analysis of the steel leaf spring has been divided into theoretical, experimental and simulation sections. The simulation of steel leaf spring has been validated with the theoretical and the experimental results. Further simulation has been done for composite leaf spring by FEA software. Finally, the result shows that the composite leaf spring has better load carrying capacity in reduced weight, and better fatigue behavior rather than the conventional steel material for the leaf spring.

Polymer composites have gained much more attention because of their lightweight, low cost, ease of fabrication, corrosion resistance, wear property etc. In this regard, natural fiber became very popular because of its biodegradability. The moisture absorption of the natural fiber reinforced polymer composites, however, causes many adverse effects on their mechanical properties as well as on long-term performance. This moisture absorbing tendency limits their uses in many engineering applications also. In this research work jute polyester composites containing 5, 10 and 15wt% jute fiber were fabricated in hand lay-up method applying various post-stress conditions and then moisture absorption tests were carried out on prepared samples. It has been found that for unstressed composites, water absorption increased linearly with increasing jute fiber content. Interestingly, with an increase in post-stress, water absorption decreased. In this regard, better results were found for composites containing a higher proportion of jute fibers.

Natural fiber reinforcement in polymer is one of the best ways to enhance mechanical properties of polymer. Hybrid composites provide the potential of achieving a balanced a pursuit of stiffness, strength, ductility and other mechanical properties. For this purpose coir and betel nut fiber were used as reinforcement in polypropylene matrix in present research. Raw coir and betel nut husk fiber were chemically treated with sodium hydroxide to increase adhesion of those fibers with polypropylene. Both raw and alkali treated fibers were utilized during composite preparation with the help of hot press technique. Fiber loading were varied at 5, 10 and 15 wt%, while coir and betel nut husk fiber ratios were varied at 1:1, 3:1 and 1:3. Tensile, flexural, impact, hardness and water absorption tests of prepared composites were subsequently conducted. All mechanical properties except tensile strength increased with increase in fiber loading. Properties of prepared composites were found better as compared to polypropylene matrix. Composites containing coir and betel nut at same ratio had better mechanical properties than composites containing those fibers at 1:3 and 3:1 ratio. On the other hand, sodium hydroxide treatment of raw coir and betel nut fiber increased mechanical properties of treated fiber composites as compared to raw fiber reinforced composite. Thus alkali treated 15 wt% coir and betel but fiber (at 1:1) reinforced polypropylene composite had the optimum set of mechanical properties among all prepared composites.

Hybrid composites have extensive engineering application where strength to weight ratio, low cost and ease of fabrication are required. In recent times hybrid composites have been established as highly efficient, high performance structural materials. Structures made of composites have a long life and need little maintenance. Present research presents a review of the current status of hybrid composite materials technology in terms of mechanical, thermal and morphological properties. Hybrid composites were manufactured with pineapple and betel nut husk as hybrid fibers and polypropylene as matrix using a hot press machine. Fiber loading was varied at 5, 10 and 15 wt%, while pineapple and betel nut husk fiber ratio was set at 1:1. For mechanical characterization, tensile, flexural and hardness tests were conducted with the composites. Thermal properties were measured using thermo gravimetric analysis. To observe surface morphology of the samples, scanning electron microscope was used. Tensile test of the composites showed a decreasing trend of tensile strength with increasing fiber content. Tensile modulus initially increased with fibers loading, then decreased at 10% fiber content. Flexural strength and flexural modulus were found higher for 10% fiber loaded composite as compared composites containing 5% and 15% fiber. From the TGA analysis, it is observed that 10% fiber loaded composites had highest thermal stability among all manufactured composites. According to scanning electron microscopy, 10% fiber loaded composite showed more adhesion as compared to 5% and 15% fiber loaded composites. Fiber agglomeration was also observed in 15% fiber loaded composite.

Natural fibers are becoming abundant and viable substitute for the synthetic fibers day by day, as synthetic fibers are expensive and nonrenewable. The main aim of present research is to evaluate the effect of sodium hydroxide treatment and banana and pineapple leaf fiber ratio on mechanical and physical properties of pineapple leaf-banana fiber reinforced hybrid polypropylene composites. Hybrid composites were prepared using a hot press machine. Raw pineapple leaf and banana fiber were chemically treated with 5% sodium hydroxide to increase adhesion between the fibers and polypropylene. Both raw and alkali treated fibers at 5 wt% were utilized during composite preparation. Pineapple leaf and banana fiber ratios were varied in 1:1, 3:1 and 1:3. Morphological analysis (scanning electron microscopy) and mechanical (tensile, flexural and hardness) tests of prepared composites were subsequently conducted. Better adhesion between the fibers and polypropylene was observed in case of treated fiber composites as compared to raw fiber composites. Scanning electron microscopic analysis also showed better bonding between the fibers and polypropylene when pineapple leaf and banana fiber ratio was 3:1. Subsequently thebest set of mechanical properties was attained for that particular fiber ratio.

Fiber reinforced polymer composites have played a dominant role for a long time in a variety of applications for their high specific strength and modulus. The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. Present research investigated the effect of alkali treatment and loading of ladies finger fiber on mechanical and thermal properties of ladies finger fiber reinforced polypropylene composites. Composites were prepared using compression molding technique. Ladies finger fiber loading were varied at 5, 10 and 15 wt%. Both raw and alkali treated ladies finger fiber were utilized to reinforce polypropylene. Mechanical (tensile, flexural and hardness) and water absorption tests and thermogrvimetric and scanning electron microscopic analysis of the prepared composites were subsequently carried out. Tensile and flexural strength decreased with fiber loading, while opposite trend was observed in case of Young's modulus, flexural modulus, hardness and water absorption. Alkali treatment of ladies finger enhanced mechanical properties of prepared composites due to better adhesion between the fiber and matrix in treated fiber composites. According to thermogrvimetric analysis, thermal stability of composites increased with fiber loading.

Use of plant and animal-based biodegradable resources as reinforcement in polymeric composites has incontestable advantages compared to synthetic fiber composites-including low density, low cost, continuous supply, easy and safe handling and supports their potential across a wide range of applications. Hybrid fiber reinforced composites are generally prepared to enhance different properties as compared to single-fiber reinforced composites. In present research, sheep wool fiber and jute fiber reinforced hybrid polypropylene composites were prepared. Their mechanical properties were examined first by varying the fiber and polypropylene ratio and then by varying wool and jute fiber ratio keeping the polypropylene quantity unchanged. Here, 5%, 10% and 15% of the fibers in a ratio of 1:1 were copulated with polypropylene in a hot press machine. For mechanical characterization, tensile, flexural, impact and hardness tests were conducted. From these tests, it was observed that the composite with 15% fiber content had the best properties. For further enhancement, two separate samples with 1:3 and 3:1 fiber ratios and 85% polypropylene were prepared. Running the aforementioned tests, it was revealed that the sample with wool and jute fiber at 1:3 ratio had the best set of properties.

In this work, Bi_0.9Ho_0.1Fe_{1 − x}Mn_xO₃ (x = 0.0, 0.05, 0.10, 0.15) nanoparticles have been successfully synthesized by sol–gel technique and subsequent annealing process. The variation of Mn doping in Bi_0.9Ho_0.1FeO₃(BHFO)on the properties such as morphological, structural, magnetic, and optical have been investigated in this study. X-ray diffraction (XRD) patterns demonstrated that Mn substitution in BHFO led to a structural transition from rhombohedral (R3c) to orthorhombic (Pn21a) phase. The field emission scanning electron microscope (FESEM) showed that Mn doping decreased particle size and consequently higher percentages of Mn resulted agglomeration of particles severely. In this case particle sizes reduced from 60 nm to 30 nm. For Mn doping up to 5% in BHFO nanoparticles, the saturation magnetization (Ms) was enhanced, implying suppression of space modulated spin structure by structural transition. However, for a further increase of doping up to 15%, the Ms was started to decrease again. UV–Visible absorption spectra revealed that Mn substitution in BHFO led to strong reduction of band gap energy significantly. Band gap decreased from 2.9 to 2.38 eV on Mn doping, which allows the absorption of light extended to visible range.

The objective of this research project was to reduce the electrical leakage, enhance the magnetic and electric property as well as to stabilize the BiFO₃ structure by co-doping La, Ba and Zr. At first the solid state sintering process was done to synthesize the Bi_.8La_XBa_{0.2 − x}Fe_.95 Zr_.05O₃ (where, x = 0.05, 0.10, 0.15, 0.20). X-ray diffraction data revealed a stabilized R₃C structure with the dopants. The amount of zirconia in B-site resulted in the reduction of vacancy which ultimately reduced leakage current. For the higher percentage of Ba²⁺ the oxygen vacancy increased which led to higher leakage current. Thus for increasing the La³⁺ up to 15 mole % with decreasing Ba²⁺ dielectric constant increased For further addition of La³⁺ (i.e. 20%) the dielectric constant decreased again. From the SEM analysis the coherent grain size was confirmed for the temperature at 950°C. With the increase of La³⁺ and decrease of Ba²⁺ the grain size increased. For the composition with 5% of La³⁺, the p-loop was found to be satisfactory with the remnant polarization of 0.25 (µC/cm²) and the coercivity of 330V. However the p-e loop for the other compositions was found to be unsatisfactory.

Titania thin film has become a great interest for the researchers due to its amazing photocatalytic activities and anti-bacterial effect. In present paper, films were deposited on normal silica glass substrate by dynamic spin coating using stable titania precursor solutions of different concentrations. Stable titania solution were synthesized by aqueous sol-gel route using titanium tetra isopropoxide. The films were calcined at 500°C were characterized with thermo gravimetry anddifferential ccanning calorimetry to determine phase transition point, X-ray diffraction for phase analysis, UV-Visible spectrometry for optical properties analysis, surface profilometer for thickness measurement, Optical Microscope and Scanning Electron Microscopy (SEM) to determine surface morphology. The objective was to analyze the effect of concentration of titania precursor solution on the surface morphology and optical properties of titania thin films. Solution of comparatively lower concentration produced uniform and stable titania film with better optical properties. With increasing concentration, the adhesion of the film degraded along with its surface morphology and optical properties.

Zinc oxide (ZnO) thin films, due to their excellent photovoltaic properties, are gaining much attention to be used as n-type semiconductor material for modern day solar cell. The change in photoelectric properties of zinc oxide with doping is an area of much consideration. In this work, 1.17%Al, 1.17%Al-2%Ca and 1.17%Al-4%Ca doped ZnO thin films were produced on glass substrate by Sol-Gel spin coating technique. Zinc acetate dihydrate, triethanolamine and isopropanol were used for making precursor solution. For Al doped ZnO, aluminum nitrate nona hydrate was added to the precursor solution as source of Al. Aluminum nitrate nona hydrate and calcium chloride dihydrate were utilized as source of Al and Ca respectively for Al-Ca doped ZnO. The films were deposited from precursor solutions at 1300 rpm for 20 seconds. After deposition, annealing was done at 520°C for one hour. Properties of deposited films were characterized by X-ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and UV-Vis spectroscopy. From XRD spectra the theoretical grain size was measured which increased from 0.31 nm to 0.33 nm because of doping. From SEM micrograph the uniformity and homogeneity of thin film was observed. The band gap of deposited thin films was measured from absorbance spectra. The band gap decreased from 3.27 eV to 3.17 eV because of doping 4% Ca in addition to 1.17% Al. From transmittance spectra, it was found that all films were transparent with average percentage of transmittance of more than 86%.

Steel has been used for many decades in structural applications because of its good combination of mechanical properties. In recent years in Bangladesh the demand for TMT 500W steel bars has increased profoundly, for its higher strength and good ductility. But fire remains one of the serious potential risks to most buildings and structures. To understand the effect of fire on mechanical properties of steel bars at elevated temperature a locally produced 500W TMT bar of 8 mm diameter has been investigated. Both macroscopy and microscopy were carried out to reveal different zones such as hardened case, soft core and transition zone in the cross-section and microstructure respectively of the steel bars in the as received condition. Finally, high temperature tensile tests were conducted at 500°C, 600°C, 650°C in steady state method at a strain rate of 0.5mm/min and the results at these 3 temperatures were noted. Data generated from the room temperature and high temperature tensile tests were compared. The test results demonstrated that the high temperature severely degrades the tensile strength of the 500W TMT steel bars and they can hardly bear any load at temperature above 600°C.

Reinforced cement concrete or RCC has become the most commonly utilized construction material for various buildings, bridges, flyovers, etc. As plain concrete can't easily withstand the stresses created by vibrations, wind or other forces; steel bars, plates or fibers are embedded as reinforcing agent, which amplify the load bearing capability. But as the temperature is increased, e.g. in case of unwanted fire the load bearing capability of steel decreases at an alarming rate, so the RCC structure becomes vulnerable at high temperatures. In our country, TMT 500W steel rebars are increasingly used as reinforcement in RCC, but there are no enough studies regarding the properties of this type of steel, especially for locally produced grades, at very high temperatures. For this study, TMT 500W steel rebars of 8mm diameter from three different local brands were collected and their composition & room temperature tensile properties were evaluated. Then microstructures at various high temperatures of 500, 600 and 650°C along with room temperature had been investigated. The results show that, the microstructure of each of as received samples at room temperature consists of ferrite and pearlite at the core and tempered martensite at the edge. At high temperatures, martensite and bainite at the edge became virtually vanished due to high temperature exposure and converted to ferrite and pearlite. The grain coarsening with increasing temperature was also significant.

Material science is the most emerging field in today's research and is getting widespread day by day. Numerical investigation of various kinds of products by using different kinds of material and changing boundary condition is getting popular because it is less time consuming and is beneficial from the cost benefit perspective. The behavior of material subjected to thermo-mechanical loads is of interest to researchers in a wide variety of discipline. Cylinders have wide use in industrial engineering like as containing various types of liquid. They often operate under static or fluctuating mechanical and thermal loads. Various methods are introduced for increasing strength of cylinders such as compound cylinder, increasing wall thickness. In this paper the analytical and numerical analysis of single and compound thick cylinder is given. The results of the analytical approach are validated to a finite element model.

The sands of Bangladesh's rivers are potentially and economically important hosts for silica sand resources. The work is based on extraction of silica sand from sands of the Padma River and quantification and qualification of extracted silica sand as glass sand. Characterization tests carried out on sand samples collected from sand bars of the Padma River in north-western Bangladesh revealed that the silica content of the sand is 76.4%. The extraction of silica sand from head sand is done by physical separation process. A chemical analysis of extracted sand is done by XRF analysis and the result shows that extracted sand contains 85.9% silica. The qualification analysis is done by glass making and characterizing the glass sample.