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This study explores the effect of in-situ alloying and volumetric energy density (VED) on the microstructure of Laser Powder Bed Fusion (L-PBF) fabricated Ti alloys. Pure Ti, Ti–5Cu, and Ti–5Cu–1Si (wt%) samples were printed using elemental powders with varying VEDs. This study investigates the influence of VED and Cu/Si additions on the growth restriction factor (Q) and columnar-to-equiaxed transition of the β phase. Pure Ti samples exhibited coarse, prior columnar β grains with an average diameter of 106 μm, and a grain shape factor greater than 3.0. In contrast, both Ti–Cu and Ti–Cu–Si samples displayed a significant fraction of equiaxed prior β grains with a near-spherical morphology. Additionally, Cu/Si addition refined the prior β columnar grains, reducing their average diameter to 37 μm and 25 μm in Ti–Cu and Ti–Cu–Si, respectively. Furthermore, the study reveals a strong dependence of microstructure on VED in the Ti–5Cu–1Si alloy. Higher VED promotes a more uniform distribution of solute elements and a lower thermal gradient, resulting in finer equiaxed β grains with an average diameter of 4.9 μm, compared to samples printed at lower VEDs. The addition of Cu and Si also significantly refined the lath-like α phase and decreased the c/a ratio of the Ti HCP lattice, introducing lattice microstrains in the Ti–Cu and Ti–Cu–Si alloys. These findings demonstrate the potential of in-situ alloying and VED optimization for tailoring microstructures in novel Ti alloys fabricated via L-PBF, paving the way for achieving superior mechanical properties.

The aim of this manuscript is to introduce and analyze a stochastic finite difference scheme for Ito stochastic partial differential equations. We also discuss the consistency, stability, and convergence for the stochastic finite difference scheme. The numerical simulations obtained from the proposed stochastic finite difference scheme show the efficiency of the suggested stochastic finite difference scheme.

In this investigation, the Mg-0.5Zn-0.5Zr/4%SiC composite fabricated by the stir casting method was subjected to multi-pass friction stir processing (MFSP) to evaluate its microstructure, hardness, dry-sliding wear, and friction properties in comparison to those of the as-cast composite (ACC). Microstructural observations revealed the formation of a Mg matrix with average grain size (AGS) of 107 ± 12 μm, uneven dispersion (agglomeration) of SiC particles in the structure, and the formation of Zr-rich phase with the chemical composition of Zr:78.42, C:19.46, Mg:1.86, and Zn:0.26 wt%, ZrC, as well as some new formed carbide-based phases mostly propagated along the grain boundaries. On the other hand, the MFSP implementation led to a significant microstructural modification, i.e., in the optimum circumstance, the AGS and SiC particle size in the stir zone was reduced by 97.28 % (107–2.9 μm) and 67.69 % (21.33–6.89 μm), respectively, and the density of the composite increased from 1.669 to 1.774 gr/cm3. According to dry-sliding wear test results, applying FSP and increasing the pass number to three reduced the wear rate and coefficient of friction (COF) of the composites by about 45 % and 24 %, respectively, compared to those of ACC. The wear resistance enhancement was ascribed to wear mechanisms changing from delamination/adhesion/severe abrasion to mild abrasion wear, which stemmed from the formation of a stable O-rich tribolayer on the worn surface of FSPed samples.

Owing to high strength and good biocompatibility, Mg–Zn binary alloys have attracted significant attention as a potential candidate for producing human implants. However due to the formation casting defects and dendritic structure, these alloys show poor mechanical and wear performances. Alloying and applying severe plastic deformation methods are suggested as two techniques for modifying and improving the above properties. In this study, dry-sliding wear and friction behaviors of the Mg–0.5Zn (MZ) alloy were enhanced by micro-alloying with Zr (0.25 wt%) and applying multi-pass friction stir processing (FSP) technique. Adding Zr reduced the average grain size (AGS) from 1.5 ± 0.3 mm in the MZ sample to about 510 ± 50 μm through the formation of evenly distributed Zr-rich particles with the chemical composition of Mg: 8.84, Zn: 0.75, and Zr: 90.41 A% in the structure. Furthermore, the attendance of thermostable Zr particles stimulated the dynamic recrystallization (DRX) during FSP and reduced the AGS to less than ≈2 μm after the 3rd FSP pass. This substantial grain refinement along with the casting defects reduction, and the fragmentation and redistribution of Zr particles enhanced the hardness and tensile properties of the substrate. Thus, the improved substrate in the FSPed samples, increased the stability of the formed tribolayer on the worn surfaces and changed the wear mechanisms from severe adhesive/delamination in the MZ alloy to mild abrasive/adhesive in the FSPed Zr-modified samples. Therefore, in the optimal condition (3-pass FSPed Mg–0.5Zn–0.25Zr sample), the hardness and total elongation percentage (EL%) increased by 55% and 648% while the mass loss and average friction coefficient (AFC) were reduced by 54% and 39%, respectively, compared to the as-cast Mg–0.5Zn alloy (under a load of 30 N).

Asthma is one of the most prevalent chronic lung diseases that afflict genetically predisposed individuals. Certain cytokine gene polymorphisms have been associated with asthma. Tumor necrosis factor-alpha (TNF-α) is a potent inflammatory cytokine that can modulate nonspecific inflammation to influence asthma. This study aimed to define the relationship between the TNF gene polymorphism at position -308 and asthma susceptibility, as well as atopic and non-atopic asthma. Using polymerase chain reaction with sequence-specific primers, we investigated genotype frequencies and alleles of a polymorphic gene coding for TNF-α in 86 pediatric patients with asthma and 470 healthy controls of the same race. Seventy-four patients underwent a skin prick test. The homozygous AA variant (-308, rs1800629) was the most common genotype among patients, accounting for 63.3% of all cases. In contrast, homozygous GG (-308) was significantly less prevalent in the patient group compared to the control group. TNF A (-308) allele frequency was 85.5% among asthma patients and 16.6% among healthy controls. The genotype and allele frequencies of TNF (-308 A>G, rs1800629) did not differ between atopic and non-atopic asthma. In conclusion, TNF (-308) AA and AG genotypes are associated with asthma susceptibility in Iranian children, although there was no significant difference in polymorphism between atopic and non-atopic asthma and no difference in asthma severity groups.

Dry-sliding wear and friction behaviors of Al–15Mg2Si–5TiB2–4TiAl3 in-situ hybrid composites were evaluated at different temperatures (100–300 °C) and loads (10–60 N). The addition of TiB2 and TiAl3 particles enhanced the wear resistance. Moreover, the severe wear transition condition was changed from 300 °C to 10 N for the as-received Al–15Mg2Si composite to 300 °C - 60 N for the as-cast Al–15Mg2Si–5TiB2–4TiAl3 hybrid composite. This change was ascribed to the presence of thermostable particles and refined/modified Mg2Si particles via nucleation mechanism. Applying thermomechanical processing and hot deformation by the extrusion process necessitated higher loads and temperatures for this transition. Indeed, fragmentation and more homogeneous dispersion of reinforcements, higher hardness and toughness of composite due to grain refinement by dynamic recrystallization (DRX), reduction and closure of casting defects, and stability of tribolayer were recognized as leading reasons for replacing severe adhesive/plastic deformation wear with the abrasive mechanism. Accordingly, this study introduced an Al matrix hybrid composite with excellent performance at elevated temperatures.

In this study, the tribological properties of Al–15Mg2Si (AC), Al–15Mg2Si–3TiB2–TiAl3 (C31), and Al–15Mg2Si–5TiB2–4TiAl3 (C54) in-situ composites were evaluated. In the as-cast state, the optimal results were obtained for the C31 sample, where the wear rate and the average coefficient of friction (ACOF) under the load of 60 N decreased by ∼54% and ∼27% compared to those obtained for the AC sample, respectively. Morphological modification of primary and eutectic Mg2Si particles and increasing the volume fractions of TiB2 particles were characterized as key factors for improving wear resistance of C31 sample. On the other hand, the presence of needle-like TiAl3 particles resulted in severe delamination and separation of tribolayer and increased mass loss of C54 sample. Alternatively, the fragmentation and redistribution of eutectic/primary Mg2Si and TiB2/TiAl3 particles during elevated-temperature deofrmation, the reduction of casting defect by thermomechanical processing effects, as well as intense grain refinement by dynamic recrystallization (DRX) improved the mechanical properties of hot-extruded samples and led to a notable enhancement in the load bearing behavior and stability of the formed tribolayer even under high loads. Therefore, the wear mechanism changed from the combination of severe delamination, adhesive, and three-body abrasive wear in the as-cast composites to mild abrasive wear in the hybrid composites subjected to hot deformation by the extrusion process. Consequently, in the optimal condition and under load of 60 N, the wear rate decreased from 29.6 to less than 10 mg/km and ACOF decreased by about 24% in hot-extruded C54 sample compared to the AC sample.

The aim of this study is to investigate the microstructure and tensile properties of Mg-0.5Zn-0.2Si-XZr (X: 0, 0.25, 0.5 wt.%) in the as-cast and multi-pass friction stir processed (FSPed) conditions. Micro addition of Zr element resulted in the average grain size (AGS) reduction from 1.65 ± 0.3 mm in Mg-0.5Zn-0.2Si alloy to less than 700 μm through the formation of Zr-rich particles evenly distributed in the structure and constitutional supercooling effect. However, the refinement efficiency of Zr was reduced by the formation of Si-containing intermetallic phases through the Si poisoning effect. Thus, agglomeration of these brittle compounds, specifically at the grain boundaries, resulted in quasi-brittle fracture mode in the as-cast samples. On the other hand, applying the FSP on Zr-free alloy improved both microstructure and mechanical properties due to grain refinement and porosity content reduction. In other words, in the optimum condition, the AGS reduced to about 5 μm and yield strength (YS), ultimate tensile strength (UTS) and total elongation percentage (EL%) improved up to 70%, 90%, and 566%, respectively, compared to the as-cast sample. On the other hand, in the Zr-modified alloys, the fragmentation and even redistribution of Zr-rich and Si-rich phases, particularly after the 2nd FSP pass, enhanced the dynamic recrystallization (DRX) through the particle stimulated nucleation (PSN) mechanism and restricted the grain growth through the Zener pinning effect. Therefore, the AGS of 2 ± 0.1 μm, UTS of 182 Mpa, and EL of 36% were achieved.

Abstract Hemophagocytic lymphohistiocytosis (HLH) disease is a severe immune dysregulation caused by mutations in genes required for lymphocyte cytotoxicity function. However, HLH‐like syndrome may develop secondary to infections, malignancy, and autoimmunity. Primary immunodeficiencies (PIDs) could predispose to HLH syndrome after uncontrolled infections. Mendelian susceptibility to mycobacterial disease (MSMD) is a PID characterized by a predisposition to clinical disease caused by weakly virulent mycobacteria, such as bacillus Calmette–Guérin (BCG). Inborn errors of interferon‐γ immunity caused by mutations in 16 genes, underly MSMD development. Here, we report a case of fatal interferon‐γ receptor 1 deficiency with disseminated BCG infection, which was initially diagnosed with HLH disease. We also include a review of cases reported in the literature.

Recently, the supply of electrical energy from sustainable and renewable energies such as mechanical, thermal and solar energy has been expanded. Piezoelectric materials are one of the best alternatives for supplying electrical energy from the mechanical energy available in nature such as mechanical force, vibration and human body movements. The applications for piezoelectric energy harvester include low power electronics or wireless sensing at relatively lower power levels (nW to mW) with an aim to reduce a reliance on batteries or electrical power through cables and realize fully autonomous and self-powered systems. In fact, the piezoelectric property is the property of a special material that enables the conversion of mechanical energy into electrical energy and vice versa. Piezoelectric property was discovered in ceramics for the first time. However, because of the need to piezoelectric materials with large surfaces and high flexibility in many applications, and the relatively low price and simple manufacturing technology of polymers in comparison with ceramics, polymers are used extensively. Poly(vinylidene fluoride) (PVDF) is a semicrystalline polymer with ferroelectric and piezoelectric properties. It has five distinctive configurations. β-phase is a polar phase showing significant piezoelectricity and pyroelectricity due to the highest dipolar moment and spontaneous polarization. In this review, PVDF polymer is introduced and then the different strategies for identification and quantification of PVDF phases are summarized. Finally, various methods including stretching, high pressure, ultra-fast cooling, melt quenching, using polar solvents, poling, copolymerization, polymer blending, electrospinning and filler addition such as carbon nanotube, clay, metals and metal salts, ceramics and etc., have been discussed for β-phase enhancement.

The aim of this manuscript is to introduce and analyze a stochastic finite difference scheme for Itô stochastic partial differential equations. We also discuss the consistency, stability, and convergence for the stochastic finite difference scheme. The numerical simulations obtained from the proposed stochastic finite difference scheme show the efficiency of the suggested stochastic finite difference scheme. [ABSTRACT FROM AUTHOR]