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Abstract This study aims to enhance the tribological properties of automotive applications by examining the effects of TiC content on the microstructure, mechanical properties, and wear behavior. This study investigates the production of Al–TiC composite strips using a novel multi-step densification process combining mechanical alloying and hot rolling with TiC concentrations ranging from 0 to 12 vol%. The novelty of this work lies in its comprehensive approach to developing and analyzing Al–TiC composite strips using a multistep densification method. This study integrates microstructural analysis, mechanical property evaluation, and detailed tribological behavior assessment under different wear loads (5–25 N). A key innovation is the application of the Abbott Firestone method to analyze worn surfaces, providing insights into optimal wear conditions. The study reveals that increasing the TiC content to 12 vol% significantly improves densification, hardness (up to 268.8% increase), and wear resistance (up to 95% improvement at a 5N load). Dry ball-on-flat sliding wear tests at loads of 5–25N demonstrate that TiC particles hindered complete delamination wear in the composite strips. The Abbott Firestone method analysis of worn surfaces indicated an optimal exploitation zone in the Al-6 vol% TiC composite at both low and high wear loads. This comprehensive approach provides valuable insights into optimizing Al–TiC composites for enhanced performance in automotive components that require improved wear resistance.

Abstract Owing to their exceptional mechanical properties, the various welding wires used to combine aluminum can meet the needs of many engineering applications that call for components with both good mechanical and lightweight capabilities. This study aims to produce high-quality welds made of AA7075 aluminum alloy using the GTAW technique and various welding wires, such as ER5356, ER4043, and ER4047. The microstructure, macrohardness, and other mechanical characteristics, such as tensile strength and impact toughness, were analyzed experimentally. To check the fracture surface of the AA7075 welded joints, the specimens were examined using optical and scanning electron microscopy (SEM). A close examination of the samples that were welded with ER5356 welding wire revealed a fine grain in the weld zone (WZ). In addition, the WZ of the ER4043 and ER4047 welded samples had a coarse grain structure. Because the hardness values of the welded samples were lower in the WZ than in the base metal (BM) and heat-affected zone (HAZ), the joints filled with ER5356 welding wire provided the highest hardness values compared to other filler metals. Additionally, the ER4047 filler metal yielded the lowest hardness in the weld zone. The welding wire of ER5356 produced the greatest results for ultimate tensile stress, yield stress, welding efficiency, and strain-hardening capacity (Hc), whereas the filler metal of ER4043 produced the highest percentage of elongation. In addition, the ER4047 fracture surface morphology revealed coarser and deeper dimples than the ER5356 fine dimples in the welded joints. Finally, the highest impact toughness was obtained at joints filled with the ER4047 filler metal, whereas the lowest impact toughness was obtained at the BM.

Abstract More focus has recently been placed on enhancing the strength, elastic modulus, coefficient of thermal expansion (CTE), wear and corrosion resistance, and other qualities of aluminum (Al) alloys by varying the quantity of ceramics added for a range of industrial uses. In this regard, Al-4.2-Cu-1.6Mg matrix nanocomposites reinforced with nano-ZrO2 particles have been created using the powder metallurgy approach. The microstructure and particle size distributions of the produced powders were analyzed using a diffraction particle size analyzer, XRD, TEM, and SEM. To achieve good sinterability, the powders were compacted and sintered in argon. The sintered nanocomposites' mechanical, elastic, and physicochemical characteristics were measured. Additionally, the behavior of corrosion, wear, and thermal expansion were examined. The results showed a decrease in the particle sizes of the Al-Cu-Mg alloy by adding ZrO2 nanoparticles up to 45.8 nm for the composite containing 16 wt.% ZrO2. By increasing the sintering temperature to 570 °C, the densification of nanocomposites was enhanced. Also, the coefficient of thermal expansion and wear rate remarkably decreased by about 28 and 37.5% by adding 16 wt.% ZrO2. Moreover, microhardness yield, strength, and Young’s modulus were enhanced to 161, 145, and 64%, respectively, after adding 16 wt.% ZrO2. In addition, increasing the exposure time was responsible for decreasing the corrosion rate for the same sample.

This article discusses the correlation between the microstructural and mechanical changes in the dual-matrix Al-Ni/SiC composites processed by Accumulative Roll Bonding (ARB) technique. Three different SiC concentrations, 1, 3, and 5% were considered to reinforce Al and Al-Ni dual-matrix composites. ARB process was applied up to 7 cycles to manufacture a composite with homogenous dispersion of the three phases. The results showed that the presence of Ni layer between Al and SiC particles enhanced the dispersion of SiC in the matrix, which positively affect the mechanical strength. The maximum tensile achieved was 257 MPa for composite containing 3 % SiC after 7 ARB cycles compared to 37.2 MPa for the AA1050. Increasing SiC content reduces the adhesion between Al and Ni layers, which reduces the elasticity of the composites. However, for the composites with 5% SiC, after 3 ARB cycles, the strength was reduced due to the cracking of the Ni layer caused by the stress concentration around the SiC particles. The hardness values of the ARBed AA1050, AA1050-Ni, and AA1050-Ni/5 wt% SiC are 85.5, 93.5, and 109.7, respectively, after 7 ARB cycles. In terms of strength, the samples with 3% SiC content showed the optimum stress enhancement with minimum reduction in the elongation, which achieve a compromised response for many applications.

Accumulative Roll Bonding (ARB) is one of the main techniques to manufacture nanocomposites, however, due to the large number of parameters that control this process, its application is relatively expensive. The present work considers a simple response surface methodology to study the interaction effect between the selected ARB parameters on the tensile strength and the hardness of the ARBed composite sheets. We investigated the characterization, modeling, and numerical optimization of the accumulative roll-bonded (ARBed) AA1050 composite sheets produced using a number of passes ranging from 1 to 7 and reinforced with different SiC content (0, 1, 3, and 5 wt%). The effect of the number of passes and SiC content on the microstructure, phase analysis, tensile, and hardness properties have been investigated for the ARBed sheets and their composites. Also, the fracture surface of the tensile-tested specimens was studied using SEM analysis. Numerical optimization was conducted using the developed model to determine the optimum parameters of the ARB process in the designed experiments. The modelling analysis results confirm the significance of the applied ARB parameters on the properties of the ARBed sheet composites. The numerical optimization analysis indicates the optimum ARB factors are 7 passes and 3.2 wt% of SiC content to produce an AA1050/Ni-SiC composite sheet with 249.2 MPa tensile strength and 107.8 HV hardness.

Abstract The safe and targeted delivery of pharmaceutical formulations has relied extensively on synthetic chemistry and other physicochemical approaches. The research paradigm is now especially changing towards green (or environmentally friendly) approaches, and several biopolymer‐based nanocarriers are marked as emerging nanomedicine tools. These have been developed to overcome problems with conventional drug carriers, which induce severe side effects, especially due to non‐specificity with detrimental effects on non‐targeted normal healthy cells. In addition, the phagocytosis of classic nanoparticles (NPs) and their degradation associated with the formation of oxygen radicals by the immune system are significant barriers for drug delivery. In this regard, protein nanocarriers appear as a promising approach to escape unwanted immune reactions. Moreover, these protein‐based NPs are generally non‐toxic, biodegradable, and even cost‐effective. As a less appreciated advantage, the surface properties of proteins are easily modified. There are, however, several challenges and limiting choices to make when choosing the type of modification to enable effective drug delivery. Here, we shed light on the role of protein nanocarriers for enhancing the bioavailability of different anti‐inflammatory drugs, including better macrophage targeting and overcoming biological barriers. This insight helps one to understand their broad utility in the treatment of inflammatory diseases and bridges the gap between naturaltherapeutic products and nanotechnology‐based delivery approaches, creating perhaps an optimal blend to meet some of our most persistent healthcare problems.

Development of layered nanostructures with distinct morphology has become an avenue of recent research to engineer targeted properties, especially for electrochemical devices. However, their remarkable characteristics are yet to be exploited for biological applications. In this work, we followed a facile and single-step method and prepared the solution grown zinc vanadium oxide multilayered nanosheets (ZnV2O4 MLNs). Field emission scanning electron microscopy shows the presence of nanosheets about 15–20 nm in height, integrated, and overlapped with one another, conferring a layered morphology. The layers are a structural mixture of triangular and hexagonal shapes. The phase pure and highly crystalline ZnV2O4 MLNs are investigated as an efficient receptor material for the electrocatalytic binding of glutathione, an important biomolecule involved in many cellular processes. This work is the first report where ZnV2O4 MLNs are employed to bind biomolecules. These nanostructured interfaces are expected to increase the effective surface area for detection, improve the planer surface of the sensor, and provide more binding sides for greater sensitivity. The developed sensor enables the sensitive detection of glutathione with outstanding detection limit down to 9 nM and ensures the 100% selectivity at a specific potential when compared to its functional and structural analogues. The study demonstrates the novel multilayer morphology-based interfaces can be a favourable platform to develop immune probes and further establishes their great potential to detect clinical biomolecules and disease biomarkers.

The development of portable and sensitive biosensors for the label-free detection of DNA has influenced fundamental biological research as well as advanced applications. Here, we report the novel microchip-based electronic devices for the efficient and sensitive detection of a crop virus i.e. Cotton leaf curl Khokran virus-Burewala strain (CLCuKoV-Bur), predominant cotton infecting virus worldwide. Three-dimensional copper nanostructures reinforced graphene nanohybrid (Cu Ns@GO) is developed via a biological synthesis approach. The hybrid consists of the typical graphene sheets, embellished with copper nanoparticles of 10–15 nm, to impart conducting and metallic character. This nanohybrid is applied as the active interface of microchips, and the surface charge of +38 mV enables successful anchoring of virus DNA as a probe to the interface. The hybridization events are manipulated as the change in the electron transport between sheets of graphene, leading to a corresponding decrease in conductance of the devices. Termed as Cu Ns@GO-microchip, the devices can detect the presence of viral DNA down to the detection limit of 200 pM. We further investigate specificity patterns and the non-complementary DNAs i.e. Cotton leaf curl Multan betasatellite, Cotton leaf curl Multan alphasatellite, and Maize insect resistance1-cystein protease genes show a negligible response generating only 10–20% of the signal. We apply this strategy to the virus-infected cotton field samples and using the devices, the level of virus infectivity can be discerned. This study suggests the potential of nanotechnology-based microchips for designing benchmark recognition interfaces, for the direct and facile monitoring of agricultural pathogens and other bio-threats.

هدفت الدراسة إلى إجراء استقصاء نوعي لتصورات عينة من المشرفين التربويين والمشرفين الأوائل وقيادات الإشراف في سلطنة عمان، عن واقع الإشراف التربوي بسلطنة عمان، من حيث مظاهر التطوير التي شهدتها المنظومة في ظل التجديدات التربوية الحالية، بالإضافة إلى التحديات التي ما زالت تعيق المشرفين التربويين عن تحقيق أهداف العملية الإشرافية على النحو المطلوب. جُمعت بياناتُ الدراسة من خلال مقابلات جماعية مع أفراد العينة الذين بلغ عددهم (60) فردًا من خمس محافظات، هي: مسقط، وظفار، وجنوب الباطنة، وشمال الشرقية، ومسندم، وقد أشارت النتائج إلى وجود عدد من التغييرات الإيجابية التي اعتبرها المشاركون تطويرًا للعملية الإشرافية، مثل التنويع في الأساليب الإشرافية، وتمكين المعلم الأول بوصفِه مشرفًا مقيمًا، وتوظيف التكنولوجيا في العملية الإشرافية، وتطوير تدريب المشرفين التربويين، إلا أن النتائج أظهرت أيضًا عددًا من التحديات التي يرى المشاركون أنها تعيق منظومة الإشراف عن تحقيق أهدافها، منها: تحديات إدارية وتنظيمية، وتحديات مالية ومادية، وتحديات فنية. وقد انتهت الدراسة بتقديم عدد من التوصيات لتطوير منظومة الإشراف التربوي في سلطنة عمان.

The fabrication of the hybrid nanocomposite surface using friction stir process (FSP) has recently gained interest in material science researchers and developers due to its superior mechanical and microstructure properties. An AA6061 wrought alloy was used as the base matrix, which is reinforced with Al2O3 and BN ceramics nanoparticles in both hybrid and mono composite surface. The mechanical properties were investigated using a compression and microhardness test; and the highest mechanical properties were obtained for the AA6061/Al2O3-BN hybrid nanocomposite. The stress strain curve showed an improvement in the ultimate stress of the hybrid nanocomposite compared to the base alloy. The microstructures of the synthesized composites were evaluated using optical and scanning electron microscopy (SEM). The FSP has a significant effect on grain refinement where the AA6061 has been refined as receiving alloy by decreasing the grain size by 29 times. Furthermore, equiaxial grains were obtained due to stirring action and FSP pin tool thread design; hence the grain aspect ratio was improved by approximately 400%. The dispersion of the Al2O3 and BN nanoparticles was successfully achieved during the current investigation, as noticed in the SEM examination analysis. Thermal expansion and electrical conductivity were decreased with reinforce the metal matrix with ceramics Al2O3 and BN nanoparticles. Moreover, the hybrid nanocomposite exhibited the minimal values of the thermal expansion and electric conductivity properties.

The astounding characteristics of the nanomaterials can be crafted to prepare tailor-made interfaces, especially for the development of biomedical applications. In the present study, we illustrate the preparation of a new class of doughnut-shaped manganese nanograins embellished on the graphene sheets to develop hybrid interfaces using a gentle and nontoxic approach. We investigate its potential to detect clinically important biomarkers and glutathione is chosen as a case study. The unprecedented structural morphology and chemical characteristics are described. Two-dimensional sheets of graphene are uniformly occupied by manganese nanograins. Each individual grain is doughnut-shaped with the external diameter of about 5−10 nm, the thickness of 2 nm with a small central cavity of about 1 nm. We show the unique morphology of hybrid offers conducting features of graphene, metallic nature of nanograins, and amelioration of greater surface area to promote enhanced binding capability. Resultantly, the hybrid yields remarkable sensitivity of 7 nM. A binding mechanism has been proposed along with extensive kinetics assessment. The developed hybrid can selectively bind glutathione in comparison of protein and non-protein molecules. The results validate that this approach can be used to design green hybrid materials for accurate diagnosis of biomarkers and metabolites.

In this work, AA 2024 wrought aluminium alloy was reinforced with Al2O3 nanoparticles to fabricate surface metal matrix nanocomposites (MMNCs) via friction stir processing (FSP). Processing parameters, namely, rotational speed, traverse speed and the number of processing passes, were investigated to study their effects on the wear resistance, mechanical properties and hardness behaviour of the MMNCs. The mechanical properties of the materials were evaluated in a tensile test, and their hardness and wear properties were determined through Vickers microhardness and weight loss tests, respectively. Microstructural observation revealed that the processing parameters influenced the mechanical properties, wear behaviour, and hardness properties of the MMNCs. Specifically, the FSP refined the microstructural grains to a level 19 times better than that achieved with base alloy, thereby fine-tuning the average base alloy grain size of 135 μm to an average of 7 μm. Increasing the number of passes improved wear resistance by an average of 39%–70%, and implementing a third round of FSP enhanced the ultimate tensile strength and Young’s modulus by 40% and 20% on average, respectively. Finally, the incorporation of Al2O3 nanoparticles increased the hardness of the MMNCs by an average of 42%.

The present study describes the potential use of 3D MnO2 nanofibrous mesh as photocatalyst for removal of organic dye. The MnO2 nanofibrous mesh has synthesized through facile, one-pot and cost-effective hydrothermal approach without using any template or other structure directing compounds. 3D MnO2 patterns clearly depict the well-dispersed nanofibers having diameter in the range of 10–25 nm, and several microns in length; the unique mesh morphology offers a large surface area to promote enhanced photocatalytic activity, and also provided a macro porous network that supported efficient oxidation. Moreover, the strong electronic cloud and high aspect ratio (HAR) MnO2 nanofibers facilitated the fast oxidation of dyes molecule in a very short period of time. The designed nanostructured material was found to possess heterogeneous photocatalytic potential against the oxidative degradation of Crystal Violet (CV) dye taken as model pollutant. The photocatalytic performance of these materials was evaluated under ultra-violet as well as visible light. Best photocatalytic performance was achieved under visible light with almost complete degradation (97%) exhibited within 90 min of irradiation time. Furthermore, the degradation efficiency of prepared photocatalyst was determined in presence and absence of initiator, hydrogen peroxide, and under different pH conditions. Finally, this technique can be easily scaled-up for removal of various polycyclic organic wastes that might be of potential industrial and environmental interests. Keywords: Manganese oxide, Nanofibrous mesh, Hydrothermal, Photocatalysis, Organic dyes, Visible light, Ultra violet light

Interesting properties of nanostructures can be tailored to generate hybrid materials with exciting morphology and chemical compositions. Assembling of different forms, morphology, and chemical complexities of nanomaterials can lead to high performance materials. We present a study where CeO2 nanocubes are grown on CNTs to produce a synergy hybrid. Microscopy showed the presence of the highly dense population of ceria cubes grown on the surface of carbon nanotubes. This special three-dimensional morphology provided micro cavities and pits network to facilitate improved mass transport and offered a large surface area to promote remarkable electrocatalysis. X-ray diffraction analysis confirmed high purity of the hybrid whereas, fourier transform infrared spectroscopy was employed to evaluate the presence and utilization of functional groups during the formation of hybrid. The hybrid exhibited excellent electrochemical potential for the detection of ascorbic acid and its fast oxidation occurred at very low potential (0.1 V). The lower detection limit was found to be 70 nM (S/N = 3). The three-dimensional morphology, versatile chemical composition with better catalytic properties can provide pathways to the development of high-performance functional hybrids for the determination of other specimen or analytes. Keywords: Nanomaterials, Hybrids, Carbon nanotubes, Ceria, Nanocubes, Electrocatalysis

Noble metal nanoparticles are highly attractive, owing to their optical, physical, electrical and chemical properties. Specifically, ease of surface modification, exceptional plasmonic and optical properties of gold nanoparticles (Au NPs) have created increasing interest in the assembly process. Once assembly is achieved successfully, the disassembly of the Au NPs is considered to be an exciting challenge. There are different kinds of forces involved in the assembly and disassembly process of Au NPs with a great deal involving the chemistry of surfactants. These forces can be externally triggered to achieve reversible assembly and disassembly. Less effort has been devoted to collate the study and mechanism involved behind environmentally or chemically triggered reversible assembly of Au NPs. Hence, the emphasis of this review is to highlight a number of promising stimuli such as light, pH, temperature and magnetic fields that can cause the reversible assembly of Au NPs. In addition, the surfactants utilized for assembly and disassembly of Au NPs under external stimuli response are examined. Furthermore, this review gives an account of the mechanism and chemistry of reversible assembly of Au NPs, taking into account the latest published literature. Indeed, it covers many ligands, biomolecules and thiol-mediated surfactants that can be linked to the surface of Au NPs and can also respond to external stimuli, realizing reversible assembly. The emerging challenges and an outlook on future developments in this research area are also discussed. The ultimate goal of this review is to encourage synthetic chemists to use ligand functionalized Au NPs (building blocks) for complex chemical systems as it will revolutionize the organic ligand synthetic processes that are responsive to different stimuli.

This study aims to perform multidirectional characterizations on nuclear shielding efficiencies on some bismuth-based glasses. Accordingly, the γattenuation coefficients for xBi2O3-(75-x)B2O3–25Li2O (x = 0, 10, 20, 30, 40, 50, 60 the 70 mol%) were widely evaluated using simulations and theoretical methods. Linear attenuation coefficient (LAC) of the glasses was obtained by the Monte Carlo general-purpose simulation code FLUKA and compared with the XCOM database up to 15 MeV. Moreover, LAC values have been utilized to evaluate related parameters like mass attenuation coefficient (MAC), total molecular cross-section (σt), total atomic cross-section (σa), half-value layer (HVL), total electronic cross-section (σe), mean free path (MFP), effective atomic number (Zeff), and effective electron density (Neff). The results noted that the XCOM and FLUKA data of the shielding parameters are in great agreement. Relatively higher density (5.818 g/cm3), greater LAC, MAC, Zeff, and lower HVL, MFP values are achieved for 70Bi2O3-5B2O3–25Li2O glass. Accordingly, this glass sample is a better gamma shield.

Nanotheranostics is an emerging frontier of personalized medicine research particularly for cancer, which is the second leading cause of death. Supramolecular aspects in theranostics are quite allured to achieve more regulation and controlled features. Supramolecular nanotheranostics architecture is focused on engineering of modular supramolecular assemblies benefitting from their mutable and stimuli-responsive properties which confer an ultimate potential for the fabrication of unified innovative nanomedicines with controlled features. Amalgamation of supramolecular approaches to nano-based features further equip the potential of designing novel approaches to overcome limitations seen by the conventional theranostic strategies, for curing even the lethal diseases and endowing personalized therapeutics with optimistic prognosis, endorsing their clinical translation. Among many potential nanocarriers for theranostics, lipid nanoparticles (LNPs) have shown various promising advances in theranostics and their formulation can be tailored for several applications. Despite the great advancement in cancer nanotheranostics, there are still many challenges that need to be highlighted to fill the literature gap. For this purpose, herein, we have presented a systematic overview on the subject and proposed LNPs as the potential material to manage cancer via non-invasive approaches by highlighting the use of supramolecular approaches to make them robust for cancer theranostics. We have concluded the review by entailing the future perspectives of lipid nanotheranostics towards clinical translation.

Recently, a growing interest has been dedicated towards improving the properties of Al alloys for use in various industrial applications. In this sense, mechanical alloying technique followed by sintering process at 460 and 560 °C in argon atmosphere was used to prepare Al2024 alloy matrix nanocomposites-reinforced by different graphene contents up to 2 wt%. Both XRD technique and TEM were employed to characterize the prepared nanocomposites powders. Microstructure analysis was performed on the sintered composites using SEM. Moreover, the relative density, corrosion rate, thermal expansion and electrical properties of the sintered nanocomposites were measured. Furthermore, their mechanical properties were measured with ultrasonic non-destructive technique. SEM and TEM micrographs revealed a uniform distribution of graphene in the Al alloy matrix. The relative density, coefficient of thermal expansion (CTE) and electrical conductivity of the specimens sintered at 460 °C decreased until reached 90.9%, 13.6 × 10−6/°C and 8.41 × 105 S/m, respectively as the graphene content increased to 2 wt%, while they increased to 93.8%, 1.5 × 10−6/°C and 4.20 × 106 S/m as the sintering temperature increased to 560 °C. On the other hand, the mechanical properties of the nanocomposites such as microhardness, elastic modulus and yield strength were enhanced to 155, 134 and 97%, respectively after adding 2 wt% graphene and sintering at 560 °C. Additionally, the corrosion rate decreased from 5.74 to 2.73 and 5.34 to 2.59 for the sample having 2 wt% graphene and sintered at 460 and 560 °C with increased the exposure from 24 to 144 h, respectively.

In present work, fine spherical shaped gold nanoparticles are prepared by using a new type of quaternary ammonium cationic surfactant (quats) i.e. didecyldimethylammonium chloride (DDAC) following one step room temperature method. Optical characterization and crystal symmetry has been observed through UV–Vis spectroscopy and XRD analysis, respectively. DDAC coated gold nanospheres (GNSs) are also analysed by using FTIR technique in order to observe binding of the ligand onto the surface of gold. Ligand weight loss has been determined by using TGA technique. Particle size has been examined by using TEM and DLS techniques both. Stability of DDAC coated gold nanoparticles are also examined by using Zeta-potential. A comparison of stabilities of different quats stabilized gold nanoparticles (GNPs) has also been discussed in the present work. Unlike usual CTAB and CTAC ligands, the low binding affinity of DDAC to the gold surface may be more efficient for ligand-exchange procedure. A sharp and fine peak of PL spectrum at around 600 ​nm has been noticed for these GNSs. These luminescent, monodispersed and fine spherical shaped GNPs of size less than 40 ​nm can be valuable in plasmonics and single molecular tracking for further characterizations.

In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (ΨP), proton projected range (ΦP), alpha mass stopping power (ΨA), and alpha projected range (ΦA) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (ΣR) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

This work presents a detailed investigation for the effect of Y2O3 and Ni additions on the densification behavior, microstructural evolution and mechanical properties of a WC-Co-TaC-NbC composite. With the aim of obtaining WC-based composites with improved fracture toughness, to be used in severe conditions of high-temperature deformation, different concentrations of Y2O3 were incorporated with and without 5 wt% Ni addition. The consolidated composites were characterized using density measurement, XRD, SEM, hardness, fracture toughness, transverse rupture strength and compression testing. Fully dense composites were obtained through the applied consolidation regime of cold compaction and sintering at 1450 °C for 1.5 h under vacuum with a relative density up to 97%. The addition of 2.5 wt% Y2O3 to the base WC composite increased the relative density and then slightly decreased with the increase of the Y2O3 content. The addition of 5 wt% Ni to the base composites significantly increased the relative density to 97%. The XRD results indicated the existence of the Co3W3C η-phase after sintering, and the intensity of its peaks was reduced with the addition of 5 wt% Ni. The microstructure of the consolidated composites consisted of three phases: WC, Co3W3C and Y2O3. The area fraction of the Y2O3 phase increased as its weight fraction increased. In terms of the fracture toughness, the transverse-rupture strength (TRS) and the compressive strength were significantly improved by the addition of 5 wt% Ni with the 2.5 wt% Y2O3. Accordingly, this composition was used to manufacture the tools for the friction stir welding of the high-softening-temperature materials, which was successfully used for 25 plunges and about 500 cm of butt joints in nickel-based and carbon–steel alloys.

The effect of isothermal multidirectional forging (IMF) on the microstructure evolution of a conventional Al⁻Mg-based alloy was studied in the strain range of 1.5 to 6.0, and in the temperature range of 200 to 500 °C. A mean grain size in the near-surface layer decreased with increasing cumulative strain after IMF at 400 °C and 500 °C; the grain structure was inhomogeneous, and consisted of coarse and fine recrystallized grains. There was no evidence of recrystallization when the micro-shear bands were observed after IMF at 200 and 300 °C. Thermomechanical treatment, including IMF followed by 50% cold rolling and annealing at 450 °C for 30 min, produced a homogeneous equiaxed grain structure with a mean grain size of 5 µm. As a result, the fine-grained sheets exhibited a yield strength and an elongation to failure 30% higher than that of the sheets processed with simple thermomechanical treatment. The IMF technique can be successfully used to produce fine-grained materials with improved mechanical properties.

This paper presents the effect of temperature and strain rate on the superplastic deformation behavior of Ti-3%Mo-1%V-4%Al, Ti-4%V-6%Al, and Ti-1.8%Mn-2.5%Al alloys, which have different initial microstructures. The microstructure, before and after superplastic deformation in the deformation regimes that provided the maximum elongation, was analyzed. The deformation regimes, corresponding to the minimum strain hardening/softening effect, provided a higher elongation to failure due to their low tendency toward dynamic grain growth. As the values of stress became steady (σs), the elongation to failure and strain-hardening coefficient were analyzed under various temperature–strain rate deformation regimes. The analysis of variance of these values was performed to determine the most influential control parameter. The results showed that the strain rate was a more significant parameter than the temperature, with respect to the σs, for the investigated alloys. The most influential parameter, with both the elongation to failure and strain-hardening coefficient, was the temperature of the Ti-3%Mo-1%V-4%Al and Ti-1.8%Mn-2.5%Al alloys and the strain rate of the Ti-4%V-6%Al alloy.

A three-dimensional study of developing fluid flow and heat transfer throughwavy and diverged-converged ducts were studied numerically for a Prandlt number 0.7and 5.85 and compared with flow through corresponding straight duct. The Navier-Stokes and energy equations are solved by using control finite volume method.Development of the Nusselt number in wavy and diverged-converged ducts arepresented for different flow rates (50Keywordsforced convection---numerical study---wavy duct---diverged-converged duct

A numerical study of two-dimensional turbulent buoyant rcirculating flow withinmechanically ventilated rooms is reported. The study involves the solution of elliptic partialdifferential equations for the conservation of mass, momentum, energy, turbulent energy andits dissipation rate in a finite difference form. These equations were solved together withalgebraic expressions for the turbulent viscosity and heat diffusivity, using (K-ε) turbulencemodel. A modified version of a two-dimensional elliptic computer code was used tosimulate the complex flows inside a slot-ventilated room. The present study demonstratesthat the flow behavior depends on several parameters, such as airflow rate, size andtemperature of the heated obstruction. Each of these parameters was modeled separately tounderstand their affects on the airflow characteristic inside ventilated room.

This work describes and analyses thermal storage system as a phase change problem whichinvolves a fluid flowing inside cooled tubes in a staggered arrangement installed in a rectangularduct surrounded by a phase - change material (water).The temperature of the fluid inside the tubes is below the freezing temperature of the PCM whichcauses ice formation around each tubes. The problem is modeled as, two- dimensional, timedependent and convection–dominated phenomena .A finite volume numerical approach isdeveloped and used to simulate the physical details of the problem .This approach is based on theenthalpy method which is traditionally used to track the motion of the liquid – solid front andobtain the temperature and velocity profiles in the liquid –phase. The study gives an instruction onthe presentation of ice – on – coil storage tank. Results of solidification experiments are used toassess and evaluate the performance.

In this numerical study a detailed evaluation of the heat transfer characteristics and flow structure in a laminar and turbulent flow through a rectangular channel containing built-in of different type vortex generator has been a accomplished in a range of Reynolds number between 500 and 100,000.A modified version of ESCEAT code has been used to solve Navier-Stokes and energy equations. The purpose of this paper is to present numerical comparisons in terms of temperature, Nusselt number and flow patterns on several configurations of longitudinal vortex generator including new five cases. The structures of heat and flow were studied, using iso-contours of velocity components, vortices, temperature and Nusselt number. This study shows that the predicted structures of fluid flow, temperature fields and Nusselt number variation are strongly affected by the presence of the turbulators. Staggered arrangement gains high Nusselt number, also the lower and upper arrangements have higher Nusselt number than plane duct. High Reynolds number (higher air inlet velocity) will enhance the Nusselt number. Increase in ribs height will enhance the heat transfer as it works as surface area and turbulator at the same time.

Numerical study on a laminar and turbulent fluid flow andtemperature distribution in a rectangular duct with six types of vortexgenerators has been carried out. A modified version of ESCEAT threedimensioncode has been used to solve Navier-Stokes and energy equations.The effect of vortex generator type, geometrical configuration, anddimensions on flow and temperature in different planes has been presented.The purpose of the present investigation is to highlight the complex threedimensionalinteraction of the vortices generated by wings and other vortexgenerators to understand how such vortices configurations structure thevelocity and temperature fields. Experiment in terms of velocities andtemperatures vectors and contours were performed on 6 configurations,which experiments are (fin, fence, rib, wing-type, rectangular-type, andwinglet-type) vortex generators The results show good agreement withpublished data.

In this numerical study a detailed evaluation of the heat transfer characteristics and flow structure in a laminar and turbulent flow through a rectangular channel containing built-in of different type vortex generator has been a accomplished in a range of Reynolds number between 500 and 100,000.A modified version of ESCEAT code has been used to solve Navier-Stokes and energy equations. The purpose of this paper is to present numerical comparisons in terms of temperature, Nusselt number and flow patterns on several configurations of longitudinal vortex generator including new five cases. The structures of heat and flow were studied, using iso-contours of velocity components, vortices, temperature and Nusselt number. This study shows that the predicted structures of fluid flow, temperature fields and Nusselt number variation are strongly affected by the presence of the turbulators. Staggered arrangement gains high Nusselt number, also the lower and upper arrangements have higher Nusselt number than plane duct. High Reynolds number (higher air inlet velocity) will enhance the Nusselt number. Increase in ribs height will enhance the heat transfer as it works as surface area and turbulator at the same time.