Average Strength Research Articles

Research on the welding process of Q355ND thick plate with narrow gap double wire submerged arc welding

Abstract Aiming at the problems of low welding efficiency and unstable quality of thick plates of marine equipment in offshore deep-water areas represented by offshore wind power, the high-efficiency welding process of narrow-gap double-wire submerged arc welding of 30 mm thick Q355ND low alloy high-strength steel plate was developed by selecting the suitable welding material and welding process parameters. The results show that the welded joint has a beautiful appearance, well-fused sides, and no defects. The structure of the heat-affected zone of the joint is mainly composed of pro eutectoid ferrite, acicular ferrite, bainite, and a small amount of pearlite. The center of the seam is composed of a large amount of massive ferrite and a small amount of bainite. The average tensile strength of the joint reaches 536.5 Mpa, and the average impact energy of the weld center at -20°C reaches 48.4 J. The average impact energy of the heat-affected zone reaches 164 J. All physical and chemical performance tests meet the standard requirements. The development of welding processes has important practical significance for improving production efficiency and product quality. It will be widely used to construct offshore wind power towers, offshore platform jackets, and other offshore deep-water engineering equipment.

Interface enhancement mechanism of rolled Mg/Al clad plate with particle interface control

In this study, the cold-spraying process was utilized to deposit Al particles onto an Al slab, an Mg slab, and both Al and Mg slabs to form an ultra-thin interlayer, and then the clad slabs were rolled at 400 °C, developing three roll-bonding processes: the roll-bonding process with cold-sprayed Al powder on the Al slab (CS-Al), the roll-bonding process with cold-sprayed Al powder on the Mg slab (CS-Mg), and the roll-bonding process with cold-sprayed Al powder on both the Al slab and the Mg slab (CS-Both). The effects of three different cold-sprayed Al particle interlayer processes on the mechanical properties of rolled Mg/Al clad plates were investigated to improve the mechanical properties. The microstructure, texture evolution, intermetallic compound formation, mechanical properties, and mechanisms involved in the Mg/Al clad plate rolling were systematically investigated. The results showed that the pre-bonding between the particles and the substrates through cold-spraying had a significant impact on the bonding strength of the Mg/Al clad plates, and the CS-Both process can increase the average shear strength of the Mg/Al clad plates to 49.24 MPa at a medium reduction rate of 37.5 %, 2.5 times that of the conventional rolling process. The CS-Both process constructed more evident dual microscopic three-dimensional interfaces and promoted more thorough atomic diffusion at the interface through the double-sided cold-spraying process. Meanwhile, the dual cold-sprayed Al coatings on both the Mg slab and Al slab underwent dynamic recrystallization during rolling to form a homogeneous unit with no additional coating interfaces. Fine grain strengthening and dislocation strengthening were judged to be important mechanisms for improving the mechanical performance of the interfacial layer.

Properties of Selected Alkali-Activated Materials for Sustainable Development

Abstract Concrete, which is based on the use of Portland cement as a binder, is often used as a structural material in the construction industry. However, the production of cement has a high energy demand. Alkaline-activated systems, for example, have the potential to replace cement with suitable substitutes, and this also puts the raw materials created as by-products from industrial processes to the fore. The presented research focuses on three selected variants, where the goal is to compare key properties from the point of view of material engineering and structural design. Tests of the mechanical properties of the examined materials are carried out and their durability is compared, namely frost resistance, resistance to chemical and de-icing substances and resistance to elevated temperature. As part of the main design criterion of structure, the resulting average compressive strengths of the selected alkali-activated materials ranged from 52.8 to 62.8 MPa.

Increasing strength properties in sinter-based additive manufacturing of SS316L via metal material jetting of sub-micron powders

Metal Binder Jetting (MBJ) 3D printing is an attractive additive manufacturing (AM) method for high volume production of metals and ceramics. However, the widespread use of MBJ has been stymied by longstanding challenges in reduced strength properties compared with traditional wrought and laser-based AM materials. In this study, we leveraged novel “drop-on-demand” Metal Material Jetting (MMJ) of sub-micron powders to fabricate SS316L samples. These samples were subjected to dilatometry, mechanical testing, and correlative materials characterization and compared to metal binder jet (MBJ) SS316L to evaluate differences in process-structure-property relationships between the two processes. Overall, MMJ SS316L possessed an average tensile yield and ultimate tensile strength of 312 ± 84 MPa and 640 ± 38 MPa respectively, greatly exceeding MBJ SS316L in the literature due to the formation of fine microstructures with an average grain size of 2.4μm. Importantly this led to significant Hall-Petch strengthening but also considerably lower average failure strains (15.5 ± 4.8 %). The process-microstructure-property relationships facilitating microstructural evolution in MMJ are discussed and further elucidated using an isotropic pressure-less viscous sintering model. Results of this model show that, although densification behaviors in MMJ were largely similar to those in MBJ, MMJ samples possessed over three-fold increase in sintering stress, defined the change in free surface energy with respect to the volumetric shrinkage, and ∼31 % reduction in grain growth due to the employment of sub-micron size powders. Overall, these results show the promise of MMJ AM for structural metals and suggest that both microstructure (and ultimately strength) of MMJ materials can be further tuned by controlling the overall sintering process.

Analysis of fiber-reinforced silicon carbide formed via material extrusion

Here, we report a method for fabrication of robust and near-net shaped carbon-fiber reinforced silicon carbide (Cf/SiC) through the additive manufacturing method of material extrusion. The addition of fibers allows for enhanced damage tolerance and thermal shock resistance but little is known about the resulting affects to resulting ink rheology, printability and resulting fiber alignment in the printed components. As such, three separate inks were developed with carbon fiber loadings of 0 %, 5 % and 15 % by volume. All inks had requisite rheology for material extrusion to fabricate near-net and dense components via pressureless sintering with densities of 93.95 %, 92.11 %, and 85.65 %, respectively. Micro X-ray computed tomography and deep learning auto-segmentation was utilized to fully describe the fiber orientation in 3D, revealing highly oriented fibers. 4-point flexure testing was performed on as-printed bend bars for all 3 ink compositions. The bars had robust average flexural strengths of 114–260 MPa, with a decrease in strength observed in fiber-reinforced samples as attributed to a decrease in sample density. However, an increase in Weibull modulus (18.0 compared to 7.0–7.3) and observed fiber pull out for the 15 % Cf samples suggest promise in toughening and reliability of fiber reinforcements. Oxyacetylene torch testing was performed on all 3 types of printed parts to study the oxidation and ablation resistance of the silicon carbide samples with fibers. Only samples with fiber reinforcements survived thermal shock of testing further emphasizing the need and benefit of fiber inclusions.

Effects of multi-layer Ti3C2Tx nanosheets on compression strength and abrasion resistance of concrete

Concrete is a leader composite material for structural use in buildings, adaptable to all locations and circumstances in view of its properties such as versatility, durability, and performance. MXenes are new two-dimensional (2D) materials that are very promising for applications in many fields due to their layered structure and physicochemical characteristics. Focused on increasing the performance of concrete structures, this work proposed the reinforcement of concrete with the addition of very small amounts (0.02 wt-%) of MXenes consisting of multi-layer Ti3C2Tx nanosheets to improve compression and abrasion resistance. The reinforced concrete specimens were tested by uniaxial compression tests and rubber-wheel abrasion tests. The results obtained were compared with reference concrete prepared without any added nanosheets. The concrete with MXenes presented higher compression strength (15% higher) in relation to the reference samples after 3 days of molding. After 28 days, the average compression strength was 20.5% higher with Mxenes, but the difference at 28 days was not statistically significant. The rubber-wheel abrasion tests showed a tendency for reduced wear rates with Mxenes, but the difference was statistically significant only for the tests with larger abrasives. Differences in macroporosity of the concretes were not found to justify the improved performance with Mxenes. The main differences due to the Mxenes reinforcement were due a smoother microtopography. It was proposed that the mechanism responsible for obtaining smoother topography with MXenes was related to the lubricious nature of the Ti3C2Tx nanosheets, that can reduce interparticle friction when a transition of the paste flow to the thickening regime occurs, which is governed by boundary lubrication.

Flight situational assessment based on complex network and MFIM-TOPSIS

In order to objectively and accurately assess the airborne flight posture in the trajectory-based operation (TBO) mode, a flight posture assessment method based on complex network and MFIM-TOPSIS is proposed. Firstly, the precise protection zone of different aircraft types is established by analyzing the risk of lateral collision between aircraft, and the flight conflict network is constructed by using the three-dimensional velocity barrier method, which is close to the TBO air operation environment, based on which six network topology indexes, such as total node degree, average point strength and network density, are selected to build the flight attitude assessment index system. To weaken the influence of the assessment subjectivity, an interaction matrix that can reflect subjective factors-objective factors is proposed. The maximum information coefficient is used to improve the coding of interaction matrix. Finally the flight attitude level status is assessed by using the superiority-disadvantage solution distance method. The simulation analysis and the example analysis of Takasaki Airport show that the evaluation model can accurately assess the air traffic situation and provide auxiliary information for controllers' decision making and command.

Pelayanan pengujian kekuatan pipa HDPE di Laboratorium Kimia Material Departemen Teknik Material dan Metalurgi FTIRS-ITS

HDPE pipes are widely used in various industries, such as drinking water and sewage infrastructure, petroleum, agriculture, and construction. The advantages of HDPE pipes include corrosion resistance, light weight, easy installation, and low maintenance costs. Checking the quality of HDPE pipes, spesifically from industry that we tested, is important to ensure infrastructure safety, prevent system failure, improve operational efficiency, obtain user satisfaction, and conserve resources. We evaluated HDPE pipes with type PN 12.5 SDR 13.6 from industry in terms of resistance to hydrostatic pressure, tensile strength, and expansion capability. The evaluation was carried out at the Material Chemistry Laboratory of the Department of Material Engineering and Metallurgy FTIRS-ITS ITS in accordance with the standards of SNI 4829.2: 2015, ASTM D 638 M, and SNI 2553: 1999. The results show that HDPE pipes can withstand hydrostatic pressure up to 12 bar without leakage. The average tensile strength is 43.34 MPa with an average elongation of 354%, indicating ductile pipe properties with necking. Pipe expansion was observed to be 0.195%, indicating a good ability of the pipe to undergo expansion.

Effect of Cu content on microstructure and properties of Ti-6Al-4V alloy fabricated by double-wire arc additive manufacturing

To solve the formation of coarse columnar β grains from Ti-6Al-4 V parts fabricated by wire + arc additive manufacturing, this study adds Cu element for in-situ alloying, effectively suppressing the growth of columnar grains and further enhancing properties. The results show that an addition of Cu element suppresses the lateral growth of β grains, eliminating the columnar structure of β grains. Compared with the Ti-6Al-4 V component, the original β grains in the Ti-6Al-4 V-10Cu component exhibit a refinement of 96 %. With an increase of Cu content, the phase structure of α-Ti transitions from lamellar to needle-like and eventually to equiaxed crystal structure. Moreover, as the Cu content rises, the precipitation of Ti2Cu increases, leading to precipitation strengthening and enhancing the microhardness. The average strength of the Ti-6Al-4 V-10Cu, Ti-6Al-4 V-11.7Cu, and Ti-6Al-4 V-15.7Cu walls is increased by 35.5 %, 56.9 %, and 71.6 %, respectively, compared with the Ti-6Al-4 V wall. The ultimate tensile strength is enhanced by 34.9 %, 49.5 %, and −1.4 %, respectively. However, the elongation is reduced by 48.6 %, 63.2 %, and 75.6 %, respectively.

Influence of a Pair of Unequal Rotational Fluxes on Entrained Gaseous Filament

Abstract Efforts are made to elucidate a comprehensive analysis of entrainment dynamics triggered by a couple of unequal rotational fluxes within a viscous pool. Cylindrical rollers are employed to establish the rotational field. The top drum is equally submerged in both phases and also it provides a constant rotational inertia. Concomitantly, the bottom roller is completely submerged in the viscous bath, and it provides an unequal rotational strength in reference to top roller. The average rotational strength of both rollers is measured using average Capillary number (Caavg). The entrainment phenomenon is strongly influenced by both Caavg and gap between the rollers (W/D). Characterization of entrained filament is elucidated by predicting the horizontal distance (L*), radial distance (r*), temporal vertical displacement (Y*), maximum vertical displacement (Ymax*), width (H*), and location of V-shaped diversion (Øs*). Characterization of liquid tip is performed by measuring the travel rate (γ*) along periphery of drum from receding to advancing junction. Air mass ejection from filament tip is analyzed by estimating the first bubble ejection time (t1st*), volume of accumulated of ejected gaseous masses (v*), and ejection frequency (f). Furthermore, the effect of gravitational pull (specified by Archimedes number, Ar) and viscous drag (measured by Morton number, Mo) on the pattern of entrained air filament is described. Lastly, an analytical framework is established to determine the width of the V-junction by balancing the important influencing forces, which are strongly affecting the filament. Analytical observations show a satisfactory agreement with numerical findings.

Fracture resistance of cement-retained lithium disilicate implant-supported crowns: Effect of material used for two-piece abutments.

This study compared the fracture strength of single lithium disilicate implant-supported crowns fabricated on two-piece abutments with various materials: ceramic-reinforced PEEK, zirconia, and lithium disilicate. Thirty-six implants were embedded in acrylic cylinders. A two-piece abutment and a crown were designed following a pre-operation scan for a maxillary left central incisor. The designed crown was used to fabricate 36 lithium disilicate crowns. The designed abutment was used to manufacture 36 abutments from 3 materials, 12 each: (A) zirconia; (B) lithium disilicate; and (C) ceramic-reinforced PEEK. Abutments were surface treated and bonded on the titanium base abutments with resin cement. Then, lithium disilicate crowns were bonded on the assigned abutments. Specimens were then subjected to dynamic loading for 1,200,000 cycles. The fracture strength (N) of the assembly was assessed using a universal testing machine. One-way ANOVA followed by multiple comparison tests was used to evaluate the effect of abutment material on the fracture strength of single implant-supported restorations at a significance of .05. The average fracture strength for the groups with zirconia, PEEK, and lithium disilicate two-piece abutments were 1362N ± 218N, 1235N ± 115N, and 1472N ± 171N, respectively. There was a significant (p < 0.05) difference in fracture strength among the groups. The lithium disilicate group had significantly higher fracture strength (p = 0.0058) than the group with PEEK; however, there was no significant (p > 0.05) difference between the other groups. Two-piece abutments restored with lithium disilicate crowns investigated in the study have the potential to withstand the average physiological occlusal forces in the anterior region.

Bond behavior of deformed rebar in concrete containing recycled brick aggregate and waste rubber

The reuse of aggregates and crumb rubber (CR) in concrete is gaining interest globally for reducing the adverse effects on the environment and maintaining construction sustainability. The bond strength of reinforcing rebars in such concrete is one of the key issues to be addressed before their practical application, particularly in structural elements. Pull-out tests were performed on 80 specimens to assess the bond performance of deformed rebars in rubberized recycled brick aggregate concrete (RRBAC). After investigating the strength properties of RRBAC, pull-out tests were performed on two sizes of cylindrical specimens. RBA%, CR%, rebar diameter (d), embedment length (le), and concrete cover-to-rebar diameter ratio (c/d) were among the test variables in this bond behavior investigation. Bond stress-slip relationships were obtained, examined, and average bond strengths were compared with the available codes. Concrete split failure was observed in 79% of the tested specimens, whereas rebar fracture was not seen in any of the tests. The bond strength was found to be decreased with the inclusion of RBAs and CRs though relative improvement was observed for higher percentage RBAs. Additionally, regression analysis was performed on the experimental data to produce a closed-form equation for forecasting the bond strength for RRBAC. With a strong coefficient of determination (R2 = 0.97) and low values of error terms, the predicted bond strengths were seen to be a good agreement with the test results.

Parametric Optimization of FDM Process for PA12-CF Parts Using Integrated Response Surface Methodology, Grey Relational Analysis, and Grey Wolf Optimization.

Efficiently managing multiple process parameters is critical for achieving optimal performance in additive manufacturing. This study investigates the relationship between eight key parameters in fused deposition modeling (FDM) and their impact on responses like average surface roughness (Ra), tensile strength (TS), and flexural strength (FS) of carbon fiber-reinforced polyamide 12 (PA 12-CF) material. The study integrates response surface methodology (RSM), grey relational analysis (GRA), and grey wolf optimization (GWO) to achieve this goal. A total of 51 experiments were planned using a definitive screening design (DSD) based on response RSM. The printing process parameters, including layer thickness, infill density, and build orientation, significantly affect Ra, TS, and FS. GRA combines responses into a single measure, grey relational grade (GRG), and a regression model is developed. GWO is then employed to optimize GRG across parameters. Comparison with GRA-optimized parameters demonstrates GWO's ability to discover refined solutions, reducing average surface roughness to 4.63 μm and increasing tensile strength and flexural strength to 88.5 MPa and 103.12 MPa, respectively. Practical implications highlight the significance of GWO in industrial settings, where optimized parameters lead to reduced costs and improved product quality. This integrated approach offers a systematic methodology for optimizing FDM processes, ensuring robustness and efficiency in additive manufacturing applications.

Effect of temperature on the uniaxial tensile properties of wood plastic composites: Experimental investigation and numerical analysis

Seven groups of uniaxial tensile experiments on wood plastic composites with a High Density Polyethylene (HDPE) matrix at different temperatures were completed in this paper. The test temperatures ranged from -60 °C to 60 °C, with a temperature difference of 20 °C for each group. All samples exhibited tensile brittle fracture. The test results showed that the tensile strength of the specimens decreased continuously with increasing temperature. Taking 0 °C as the reference temperature, the ultimate strength of the sample at -60 °C was 1.63 times that at 0 °C. When the temperature was 60 °C, this value was 0.41. Then, it can be calculated that the ratio of the strength of the sample at -60 °C to that at 60 °C was approximately 3.93, and the corresponding ratio of the elastic modulus was approximately 4.52. This shows that the mechanical properties of WPC are sensitive to changes in temperature. The variation coefficient of the average strength and elastic modulus of WPC for different specimens at different temperatures was less than 0.17, showing good stability due to the small dispersion of mechanical properties among different samples at any specific temperature.

Structure refinement and performance balance of high-strength aluminum alloys using an improved thermomechanical treatment process

The microstructure of 7A85 aluminum alloy forgings often contains coarse second-phase particles and grains. To improve the microstructures and balance the properties, we used an enhanced thermomechanical treatment process that included multiaxial hot forging, multiaxial cryoforging (MACF), and three-step aging treatment. We thoroughly investigated the effects of MACF with 1–3 passes on the evolution of microstructure, three-dimensional (3D) mechanical properties at the center and edge, fracture toughness, and corrosion resistance of the alloy. Our findings revealed that multiaxial hot forging had a limited ability to crush the coarse second-phase particles. However, the higher flow stress and compound brittleness of MACF resulted in a significant increase in particle fragmentation and driving force for precipitation. Additionally, under MACF, massive dislocations proliferated due to the inhibition of dynamic recovery, forming large orientation gradient regions, which promote static recrystallization and grain refinement during solution treatment. As the number of MACF passes increased from one to three, the effect of particle crushing initially increased and then plateaued, the 3D grain sizes first decreased and then slightly increased, and the spacing of grain boundary precipitates (GBPs) increased. The dense and uniform precipitates, finest equiaxed grains, a low fraction of coarse particles, and large GBP spacing in MACF2 resulted in the higher strength, highest elongation with minimal anisotropy, superior fracture toughness, and enhanced corrosion resistance. Ultimately, MACF2 demonstrated the best overall performance and good homogeneity, with an average 3D ultimate tensile strength, average 3D yield strength, average 3D elongation, and fracture toughness at the center of 548 MPa, 476 MPa, 13.4%, and 42.5 MPa m1/2, respectively. These values were respectively 4.2%, 1.9%, 50.6%, and 13.9% higher than those of the uncompressed sample.

#659 Analysis of functional brain connectivity in patient with end-stage kidney disease undergoing peritoneal dialysis

Abstract Background and Aims Neurological complications are common in patients with end-stage kidney disease (ESKD). However, the mechanisms underlying neurological complications of ESKD are poorly understood. Research on brain connectivity in patients undergoing peritoneal dialysis (PD) is limited. In this study, we aimed to examine alterations in functional brain connectivity in patients with ESKD undergoing PD compared to the control group using functional near infrared spectroscopy (fNIRS). Method We prospectively enrolled 20 patients with ESKD who had been receiving PD for more than 6 months and had no prior history of psychiatric or neurological diseases, along with 20 healthy controls. The fNIRS data were obtained using an NIRSIT Lite instrument. After processing all the data, we used Pearson correlation analysis to create a weighted connectivity matrix. Functional connectivity measures were derived from the connectivity matrix using graph theory. Functional connectivity measures were compared between the controls and patients with ESKD undergoing PD. Results The average degree, average strength, and small-worldness were significantly lower in patients with ESKD undergoing PD than in the controls (9.333 [8.000∼11.433] vs. 12.733 [9.600∼13.400], p = 0.030; 6.865 [4.768∼7.560] vs. 8.432 [6.593∼9.432], p = 0.036; 0.836 [0.724∼0.900] vs. 0.949 [0.882∼0.972], p = 0.025, respectively). Conclusion This study demonstrated significant alterations in functional brain connectivity in patients with ESKD undergoing PD, suggesting that functional brain connectivity is significantly reduced in patients with ESKD undergoing PD when compared with that in healthy controls.

Faraday rotation as a probe of radio galaxy environment in RMHD AGN jet simulations

Abstract Active galactic nuclei (AGN) play an integral role in galaxy formation and evolution by influencing galaxies and their environments through radio jet feedback. Historically, interpreting observations of radio galaxies and quantifying radio jet feedback has been challenging due to degeneracies between their physical parameters. In particular, it is well-established that different combinations of jet kinetic power and environment density can yield indistinguishable radio continuum properties, including apparent size and Stokes I luminosity. We present an approach to breaking this degeneracy by probing the line-of-sight environment with Faraday rotation. We study this effect in simulations of three-dimensional relativistic magnetohydrodynamic AGN jets in idealised environments with turbulent magnetic fields. We generate synthetic Stokes I emission and Faraday rotation measure (RM) maps, which enable us to distinguish between our simulated sources. We find enhanced RMs near the jet head and lobe edges. We show that increasing the environment density and the average cluster magnetic field strength broadens the distribution of Faraday rotation measure values. We study the depolarisation properties of our sources, finding that the hotspot regions depolarise at lower frequencies than the lobes. We quantify the effect of depolarisation on the RM distribution, finding that the frequency at which the source is too depolarised to measure the RM distribution accurately is a probe of environmental properties. This technique offers a range of new opportunities for upcoming surveys, including probing radio galaxy environments and determining more accurate estimates of the AGN feedback budget.

#3109 Sarcopenia in peritoneal dialysis patients

Abstract Background and Aims Sarcopenia is considered a frequent cause of morbidity and mortality among patients with chronic kidney disease (CKD). In clinical practice, tools such as handgrip strength and bioelectrical impedance analysis (BIA) can help us diagnose sarcopenia and possibly predict clinical outcomes. However, the outcomes associated with this diagnosis in the population of patients under peritoneal dialysis (PD) and the consequent importance of the implementation of these tools is not clear. Method Single-centre retrospective study with patients who started peritoneal dialysis (PD) between January 1st 2017 and December 31st 2023, with a follow-up of 18 months or until technique dropout. Demographic, clinical data and outcomes were collected. Muscle strength (measured by handgrip strength with a dynamometer) and muscle mass (estimated through BIA-derived lean tissue index (LTI)) were also evaluated. Sarcopenia was considered when low strength (handgrip strength values &amp;lt;27 kg and &amp;lt;16 kg for men and women, respectively) and loss of muscle mass (LTI &amp;lt;10th percentile, relative to an age and gender-matched healthy population) were present. Results Fifty-three patients were included, with 66% male and a mean age of 58 ± 15 years. Comorbidities included hypertension in 88.7%, diabetes mellitus (DM) in 26.4% and coronary artery disease (CAD) in 17.0%. PD vintage was 23 months (IQR 21) and most were on continuous ambulatory peritoneal dialysis (75.5%). Median Clinical Frailty Score (CFS) was 2 (IQR 1). Mean LTI was 13.2 ± 2.7 kg/m2 and average handgrip strength was 28.4 ± 8.8 kg in the right arm and 26 kg (IQR 13) in the left. Reported outcomes of number of peritonitis, outer peritoneal catheter infection, hospitalizations and MACE (Major Adverse Cardiovascular Events) episodes were low. There were 3 reported deaths during follow-up. Six patients were considered sarcopenic, with 66% male and a mean age of 58.1 ± 14.9 years, with DM in 50%, hypertension in 100% and CAD in 33.3%. Median LTI was 9.4 (IQR 1.2), with left and right median hand grip of 24 (IQR 10) and 26 (13), respectfully. Outcomes were also low, with no statistically significant difference between sarcopenic and non-sarcopenic patients. Conclusion Despite being considered an indication of higher morbidity and mortality, the diagnosis of sarcopenia was not associated with worse outcomes in patients under peritoneal dialysis.

Microstructure and mechanical properties of wire-arc directed energy deposited Al-Mg-Sc aluminum alloy: As-deposited and aging heat treated

In this study, Al-Mg-Sc aluminum alloys were fabricated using wire-arc directed energy deposition. The focus of the study was to analyze the microstructure and mechanical properties of these alloys. Comparative analysis was conducted on the samples obtained from the as-deposited and aging treated, respectively. Furthermore, the precipitation process of the second phases and the associated strengthening mechanism were elucidated. The findings revealed that the presence of precipitated Al3(Sc,Zr) particles acted as heterogeneous nucleation nuclei of α-Al, facilitating the formation of equiaxial grains. During the subsequent aging treatment, the secondary Al3(Sc,Zr) particles precipitated directly without transitioning through intermediate phases. Additionally, the experimental results demonstrated that these secondary Al3(Sc,Zr) phases hindered the dislocation movement, leading to enhanced mechanical properties in Al-Mg-Sc alloys through precipitation strengthening. In the horizontal direction, the average ultimate tensile strength (UTS) and yield strength (YS) were measured as 361 ± 5 MPa, 251 ± 4 MPa, and 281 ± 6 MPa, 179 ± 6 MPa in the vertical direction, respectively. The elongations were found to be 15.8 ± 0.8% and 4.0 ± 0.5% in the horizontal and vertical directions, respectively. The observed variations in mechanical properties were attributed to the presence of interlayer pores.

Effect of SS-316L and nickel-based interface powders on joint characteristics of microwave welded SS-316L plates

Microwave energy has been exploited as a rapid and volumetric heating source in various manufacturing applications, such as microwave joining. This study used stainless steel (SS-316L) plates to be microwave-joined at 2.45 GHz. The microwave hybrid heating (MHH) technique was used to prepare joints inside a microwave applicator using nickel-based (EWAC 1004EN) and SS-316L interfacing powders at 900 W. Microstructural and mechanical characterizations of the developed joints were performed to understand the effect of the interface powder on weld quality. Microstructural observations revealed adequate metallurgical bonding between interfacing powders and bulk metal with columnar and dendritic grains (EWAC-based joint) and equiaxed grains (SS-316L-based joint). The phase analysis revealed the presence of intermetallic phases such as iron-nickel, chromium carbide, and chromium iron carbide in EWAC-based joint and iron-nickel, nickel-chromium, and chromium carbide in SS-316L-based joint, which contribute to enhanced joint microhardness compared to base alloys. A larger grain size, more low-angle boundaries, and higher misorientation angles were found in the EWAC-based joint. Furthermore, the average ultimate tensile strength of SS-316L-based joints was 26% higher, with a 6.9% enhanced elongation, than that of EWAC-based joints. The EWAC-based joint exhibited better corrosion resistance than that of SS-316L-based joint.