High Strength Research Articles

Extra Medullary Fixation in Unstable Proximal Femoral Fractures by PF-LCP.

Perception that extra-medullary fixation of these fractures are fraught with difficulties and deficiencies is becoming inappropriate. This device provides angular stable fixation retaining fracture biology with minimum interference to osseous and soft-tissue vascularity and it does not require reaming which destroys 80% of endosteal vasculature for 6-12weeks. PFLCP averts iatrogenic fracture in lateral trochanteric wall (LTW) which is frequent with DHS, protects LTW from secondary fracture in post-operative period. Aim is to assess outcome of unstable proximal femur fracture fixation by PFLCP. Study included 64 from 2016 to 2020, divided in two groups. (A) Unstable intertrochanteric fracture and (B) subtrochanteric fracture (Seinsheimer types II-V). All fractures fixed by MIPO with PFLCP. Loss of reduction, infection, cut-out, cut-through, backing of screws, bending or breaking of plate and screw, malunion, non-union and revision were evaluated. Fracture healing and functional recovery assessed by Reborne Score and Parker Mobility Score (PMS) respectively. Out of 64, 24 achieved pre-injury PMS, 32 declined by 1 point, 6 declined by 2 points and 1 by 3 points, one required revision. Using various parameters 37.5% patients had excellent results and 50% had good results, 9.38% had average and 3.12% had poor result. None reported non-union or breakage of plate. PFLCP provides angular stable fixation, torsional stability with high biomechanical strength to resist deforming stresses. MIPO avoids soft-tissue stripping reducing blood-loss, retains periosteal blood supply to inter-fragmentary bone fragments, enhancing fracture healing, reducing complications, such as delayed healing, nonunion, infection and implant failure.

Red mud and bismuth oxide based X-ray shielding tiles for upcoming hospitals: A comprehensive study on phase quantification and physical properties

Red mud (RM) is a solid alumina industry waste generated in millions of tonnes and is stockpiled across the globe. From the environmental perspective, research and innovation strategies are utmost necessary for the minimization and utilization of red mud. In an attempt to develop an environmentally friendly technology, RM was utilized with Bi2O3 for the development of radiation shielding tiles. RM is a source of many metal oxides, which react with Bi2O3 during sintering and form various high-dense phases. The Rietveld refinement of the tiles sintered from 600 to 1100°C confirms the formations and transformations of several high-dense phases like Bi24Ti2O40, BiFeO3, and Na0.5Bi0.5TiO3. The RM-Bi2O3 mixture sintered at 1100°C (RMBi1100) exhibited high density (3.64 ×103 kg m−3), less porosity (10 %), and flexural strength of 24 MPa. The results showed that the developed sample has a half-value layer (HVL) of 1.15 mm at 140 kV. The 15.5 mm, 13.5 mm, and 7 mm thick RMBi1100 tiles can effectively replace 2.3 mm, 2 mm, and 1 mm thick lead sheets respectively, that are used to establish radiation shielding structures in computed tomography, radiography & fluoroscopy, and dental infra oral radiography installations, respectively. It can promote the utilization of red mud and thereby reduce the environmental pollution associated with lead and red mud.

Advancements in Coordination Chemistry and Trends in the Chemical Industry: Applications and Implications

Abstract: Metal foams offer a compelling combination of properties, including low density, sound absorption, high compressive strength, and stiffness. This project focuses on the damping behavior of aluminum foams for applications in automobiles and various industries. Aluminum foams excel in being lightweight, exhibiting high compressive strength, and offering excellent stiffness. However, their wear resistance is a limitation. To address this and enhance durability, a diamond-like carbon (DLC) coating is applied to the surface. The complex geometry and surface of aluminum foams pose a challenge for the coating process. Therefore, the project employs the well-established cataphoretic deposition technique, an electro-chemical process. This research investigates the potential of carbon-coated aluminum foam for vibration mitigation in automobiles and industrial applications by analyzing its damping properties and improved wear resistance through the DLC coating

Mechanically Robust Biopolymer Optical Fibers with Enhanced Performance in the Near-Infrared Region.

Polymer optical fibers (POFs) are lightweight, fatigue-tolerant, and suitable for local area networks, automobiles, aerospace, smart textiles, supercomputers, and servers. However, commercially available POFs are exclusively fabricated using synthetic polymers derived from nonrenewable resources. Recently, attempts have been made to fabricate biocompatible and biopolymeric optical fibers. However, their limitations in mechanical performance, thermal stability, and optical properties foil practical applications in waveguiding. Here, we report a comprehensive study of the preparation of biopolymer optical fibers with tailored mechanical strength, thermal properties, and their short-distance applications. Specifically, we use alginate as one of the key components with methylcelluloses to promote readily scalable wet spinning at ambient conditions to fabricate 21 combinations of composite fibers. The fibers display high maximum strain (up to 58%), Young's modulus (up to 11 GPa), modulus of toughness (up to 63 MJ/m3), and a high strength (up to 195 MPa), depending on the composition and fabrication conditions. The modulus of toughness is comparable to that of glass optical fibers, while the maximum strain is nearly 15 times higher. The mechanically robust fibers with high thermal stability allow rapid humidity, touch sensing, and complex shapes such as serpentine, coil, or twisted structures without losing their light transmission properties. More importantly, the fibers display enhanced optical performance and sensitivity in the near-infrared (NIR) region, making them suitable for advanced biomedical applications. Our work suggests that biobased materials offer innovative solutions to create short-distance optical fibers from fossil fuel-free resources with novel functionalities.

Mechanically Robust and Electrically Conductive Hybrid Hydrogel Electrolyte Enabled by Simultaneous Dual In Situ Sol-Gel Technique and Free Radical Copolymerization.

Mechanically robust and ionically conductive hydrogels poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonate-lithium)/TiO2/SiO2 (P(AM-co-AMPSLi)/TiO2/SiO2) with inorganic hybrid crosslinking are fabricated through dual in situ sol-gel reaction of vinyltriethoxysilane (VTES) and tetrabutyl titanate (TBOT), and in situ radical copolymerization of acrylamide (AM), 2-acrylamide-2-methylpropanesulfonate-lithium (AMPSLi), and vinyl-SiO2. Due to the introduction of the sulfonic acid groups and Li+ by the reaction of AMPS with Li2CO3, the conductivity of the ionic hydrogel can reach 0.19Sm-1. Vinyl-SiO2 and nano-TiO2 are used in this hybrid hydrogel as both multifunctional hybrid crosslinkers and fillers. The hybrid hydrogels demonstrate high tensile strength (0.11-0.33MPa) and elongation at break (98-1867%), ultrahigh compression strength (0.28-1.36MPa), certain fatigue resistance, self-healing, and self-adhesive properties, which are due to covalent bonds between TiO2 and SiO2, as well as P(AM-co-AMPSLi) chains and SiO2, and noncovalent bonds between TiO2 and P(AM-co-AMPSLi) chains, as well as the organic frameworks. Furthermore, the specific capacitance, energy density, and power density of the supercapacitors based on ionic hybrid hydrogel electrolytes are 2.88Fg-1, 0.09Whkg-1, and 3.07kWkg-1 at a current density of 0.05Ag-1, respectively. Consequently, the ionic hybrid hydrogels show great promise as flexible energy storage devices.

Development of Ultra-High-Performance Concrete Using GGBS and Alccofine

Abstract: Ultra-high-performance concrete, or UHPC, is a cementitious mixture that is distinguished by its exceptionally high compressive strength—more than 120 MPa as well as its remarkable toughness, tensile ductility, and longevity. Ground Granulated Blast Furnace Slag (GGBS) and Alccofine (AF) are commonly used in the matrix composition to increase the particle system's packing density and subsequently enhance the matrix's strength in order to guarantee that UHPC has the proper strength. To investigate the engineering properties of ternary blended UHPC with GGBS, AF, a comparative study was conducted. In comparison to the control UHPC mix, the ternary blended UHPC mix's mechanical and durability qualities were improved by the percentage variation of AF within specific bounds. In this study, the experimental work included mix proportioning and preparation of ternary blended UHPC specimens and various tests like Compressive Strength, Split Tensile Strength, Flexure Strength and RCPT (Rapid Chloride Penetration Test) were performed in the laboratory. The results show that under normal water curing conditions, the strength qualities of UHPC based on GGBS are considerable, up to a cement replacement level of 40%. In addition, compared to the binary counterpart, the mixture of 20 Percent AF and 40 Percent GGBS showed better mechanical and durability properties.

Cyclic inelastic performance evaluation of locking bolt demountable shear connectors in steel-concrete composite structures

This study extends the research on the Locking Bolt Demountable Shear Connector (LBDSC), previously introduced and extensively analysed under monotonic loading through both experimental and numerical methods. The focus here shifts towards the inelastic cyclic performance of the LBDSC, a critical aspect for applications in seismic regions. The LBDSC, designed for use in composite floors or decks, such as in-situ solid slabs, profiled deck slabs, or precast slabs in buildings and bridges, features a grout-filled steel tube bolted to the top flange of steel sections. The design incorporates a unique 'locking bolt' technique to counteract the influence of construction tolerances on undesirable initial slip behaviour, significantly facilitating the deconstruction and reuse of steel sections without the need for recycling. Following the Eurocode 4 guidelines, a series of standard push out tests were conducted to explore the LBDSC's inelastic cyclic characteristics. The experimental results confirm the LBDSC's capability for high strength, high initial stiffness, and adequate slip capacity under cyclic loading, with ductile shear failure modes observed at the bolt shank and local concrete crushing above the steel flange. The cyclic loading tests reveal a larger zone of damaged concrete compared to monotonic loading conditions, yet the monotonic and cyclic force-slip curves closely align. Based on these findings, and supported by validated finite element analyses, this paper proposes theoretical monotonic and cyclic models for LBDSC under push out loading, aimed at accurately predicting the load-slip response. These models are intended to facilitate the efficient analyses, design and numerical modelling of composite structures incorporating LBDSCs, and to support the broader adoption of LBDSCs in earthquake-prone areas, promoting sustainable steel-concrete composite construction practices.

Multiscale analysis of microstructure-based bending characteristics of advanced high strength dual-phase steel

Multiscale analysis of microstructure-based bending characteristics of advanced high strength dual-phase steel

High ionic strength vector formulations enhance gene transfer to airway epithelia.

A fundamental challenge for cystic fibrosis (CF) gene therapy is ensuring sufficient transduction of airway epithelia to achieve therapeutic correction. Hypertonic saline (HTS) is frequently administered to people with CF to enhance mucus clearance. HTS transiently disrupts epithelial cell tight junctions, but its ability to improve gene transfer has not been investigated. Here, we asked if increasing the concentration of NaCl enhances the transduction efficiency of three gene therapy vectors: adenovirus, AAV, and lentiviral vectors. Vectors formulated with 3-7% NaCl exhibited markedly increased transduction for all three platforms, leading to anion channel correction in primary cultures of human CF epithelial cells and enhanced gene transfer in mouse and pig airways in vivo. The mechanism of transduction enhancement involved tonicity but not osmolarity or pH. Formulating vectors with a high ionic strength solution is a simple strategy to greatly enhance efficacy and immediately improve preclinical or clinical applications.

Evaluation of tribo-mechanical measurements and thermal expansion of Cu-based nanocomposites reinforced by high strength hybrid ceramics

It is known that Copper’s (Cu) electrical conductivity makes it a desirable material for use in industry. Due to poor properties such as hardness, thermal expansion, and corrosion resistance, its applications are limited. This manuscript solves these problems while maintaining no breakdown in electrical conductivity. In this study, high-strength ceramics (SiC nanoparticles and graphene nanosheets) were used as reinforcements in the manufacture of Cu-based hybrid nanocomposites using powder metallurgy technique. X-ray diffraction analysis (XRD) was used to investigate phase composition and crystal size of the milled powders. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM), respectively examined the microstructure of the prepared powder powders and sintered nanocomposites. Then, various properties of the sintered samples are measured, including physical, electrical and thermal properties and wear resistance. The obtained XRD technique and TEM images showed decreases in the crystal and particle size of milled samples reaching up to 14.08 and 28.30 nm, respectively for the sample contained 8 vol. % SiC + 0.8 vol. % graphene (SG8). A surprising improvement in the mechanical properties of up to 809.15, 341.84 MPa and 336.56 GPa for microhardness, strength and longitudinal modulus for the sample containing the highest reinforcements, achieving an improvement of up to 122, 61.37 and 41 percent compared to the Cu matrix. Moreover, there was a noticeable improvement in the coefficient of thermal expansion (CTE) and wear rate values of the samples by increasing the percentages of hybrid reinforcements in the examined sintered nanocomposite samples. The Sample SG8 recorded the lowest value, decreasing by about 50.2 and 76.5% compared to the SG1 sample. Finally, adding reinforcements to the Cu matrix had a negative effect on the relative density and electrical conductivity, and the lowest values was 92.94% and8.59 × 106 S/m, respectively for the SG sample.

Cyclic testing and diagonal strut modelling of different types of masonry infills in reinforced concrete frames designed for modern codes

This article presents an experimental study on cyclic testing of full-scale reinforced concrete (RC) frames designed for modern codes with three different masonry infills: burnt clay brick, fly ash brick, and autoclaved aerated concrete (AAC) block masonry. A digital image correlation (DIC) system was used to study, in detail, the failure pattern and the complex interaction between the infill and the surrounding frame. The experimental results were compared with the pre-existing analytical models for strength and stiffness to determine the best-fit model. The experimental results indicated that the masonry-infilled frames had higher strength, stiffness, and energy dissipation capacity compared to the bare frame, and brittle modes of failure were avoided due to the design for modern codes. The masonry infill altered the RC frame’s deformation pattern by constraining the end portions of the columns from moving laterally, resulting in widespread flexure cracks throughout the column’s height, unlike the bare frame, where cracking was limited to the end portions. The modification was minimal in the case of AAC block masonry infill. The AAC block infilled frame reached different damage states at lower drifts than the other two infill types. The strength and stiffness, separately, were found to be in good agreement with some of the existing models; however, none of the considered models could predict both stiffness and strength accurately.

Enhancing the Mechanical Strength and Thermal Stability of Polylactic Acid (PLA) with the Addition of Epoxidized Waste Cooking Oil (EWCO)

Polylactic Acid (PLA) comes from renewable resources, has a reasonable biodegradability rate, and is used in biomedical, food packaging, textiles, and agricultural applications. PLA offers high mechanical strength and the ability to compost, similar to polyethylene terephthalate (PET) and nylon. However, the brittleness of PLA has always limited its usage. Therefore, bio-based plasticizers in the biopolymer matrices can increase flexibility (elasticity), durability, and workability. This study aims to determine the optimal blending ratio for the PLA blended with epoxidized waste cooking oil (EWCO) to enhance the mechanical and thermal properties of PLA/EWCO. The mechanical strength test consists of the hardness test (N/mm<sup>2</sup>), flexural strength (MPa), and impact energy (kJ/m<sup></sup>) adopted to evaluate the plasticizing characteristics. The thermal stability analysis involves glass transition temperature (T<sub>g</sub>) (°C), cold-crystallization temperature (T<sub>cc</sub>) (°C) and melting temperature (T<sub>m</sub>) (°C). The blending ratio is 97.5PLA/2.5EWCO, 95PLA/5EWCO, 92.5PLA/7.5EWCO and 90PLA/10EWCO. As a result, 97.5:2.5 of PLA/EWCO reduces intermolecular interactions by stimulating more free volume in biopolymer chains’ mobility and enhancing the flexibility and elasticity of the PLA blends. Ultimately, the brittleness of PLA decreased with increasing EWCO bio-based plasticizer.

Control mechanism of short-term fertilization with cattle manure on the release characteristics of soil colloids in farmland: grain size and physicochemical properties

BackgroundUnderstanding the release characteristics of soil colloids is a prerequisite for studying the co-transport of colloids and pollutants in subsurface environment. As a crucial agricultural management measure, fertilization not only alters the material composition of farmland soil, but also significantly regulates the properties and release patterns of soil colloids. This study systematically investigated the regulatory mechanism of short-term cattle manure fertilization on the macroscopic release and microscopic properties of soil colloids with different particle sizes, providing a theoretical foundation for subsequent research on the fate and transport of agricultural non-point source pollutants.ResultsThe colloids in natural agricultural soil primarily consist of inorganic components. Graded extraction of the colloids has revealed that the combined proportion of colloids with particle sizes of 1–2 μm and 0.45–1 μm accounts for approximately 80.5%. Applying cattle manure inhibits the release of soil colloids, and the content of large particle size (1–2 μm) components increases. The content of organic colloids is increased due to the high total organic carbon (TOC) in cattle manure, particularly those with a particle size less than 1 μm. The characterization of organic colloid components revealed a significant increase in aromatic carbon and oxygen-containing functional groups, while the aliphatic content decreased. The response sequence regarding changes in functional groups within organic colloids induced by fertilization was as follows: –CH3, –CH2 > C–O > –OH > C=C. Fertilization promotes the release of 1:1-type inorganic mineral colloids, increasing the content of poorly crystalline minerals. The retention of aromatic carbon and oxygen-containing functional groups by poorly crystalline mineral colloids served as the primary mechanism leading to their increased content levels. Changes in environmental factors significantly impacted the release and properties of soil colloids. Conditions such as low cationic valence, high ionic strength, and high pH promoted the release of soil colloids.ConclusionsThe short-term fertilization resulted in a reduction in the release of soil colloids and brought about significant alterations in their particle size composition and properties. The findings of this study provide valuable insights into understanding the impact of fertilization-induced colloid release on the environmental behavior of agricultural non-point source pollutants.

Preparation and characterization of ox bone powder and bamboo fibers reinforced hybrid epoxy composites

Composite materials are one of the fastest growing when compared with metal, ceramic, and polymer due to their high specific strength, stiffness, and versatile application in various fields. This study aimed to develop an ox bone powder and bamboo fiber-reinforced hybrid epoxy composite for stock and bumper applications and investigate the effect of the reinforcements on the composite’s mechanical properties. The reinforcements used in this work were random orientations of animal bone (ox) powder of 75 microns and bamboo fiber. The matrix used for this work was epoxy resin. Composite materials were prepared using the hand layup method with a 40% weight fraction of reinforcement (bone powder and bamboo fiber) and a 60% weight fraction of epoxy resin matrix. Five different combinations of bone powder and bamboo fiber with a fixed amount of epoxy resin were used for this work. The combinations of bamboo fiber and bone powder were: 40% bamboo fiber with 0% bone powder; 30% bamboo fiber with 10% bone powder; 20% bamboo fiber with 20% bone powder; and 0% bamboo fiber with 40% bone powder. The mechanical properties studied were compressive strength, impact strength, and flexural strength. In addition, water absorption was studied for all combinations. The maximum results of the flexural and impact strengths were 278.91 MPa and 7.5 J/m, respectively, at a 0:40 (bone powder: bamboo fiber) composite. The maximum compressive strength and the lowest absorption obtained were 283.3 MPa and 1.05%, respectively, at the 40:0 (bone powder: bamboo fiber) composite. For the hybrid composite case, optimal flexural and impact strengths were 236.72 MPa and 6.66 J/m, respectively, and water absorption was 1.52% at 10:30 (bone powder: bamboo fiber). Since reasonable flexural strength, impact strength, and water absorption were obtained with the hybrid composite of 10:30 (bone powder: bamboo fiber), this combination of the hybrid composite is recommended for stock and bumper applications.

High and long-lasting antifogging performance of silane based hydrophilic polymer coating

The inevitable presence of fog causes a loss of light transmission in optical materials and leads to many unacceptable and serious consequences. A promising strategy for avoiding fog is to modulate the wettability of the material surface and further change the formed way of droplets. Although many works achieved high antifogging coatings, they are lack of the long-lasting antifogging at varied conditions. In this work, a high adhesion strength and persistent antifogging capability hydrophilic coating is obtained by utilizing silane coupling agents containing double bonds such as triethoxyvinylsilane (A151) and 3-(trimethoxysilyl)propyl methacrylate (KH570) with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and then compositing with poly(vinyl alcohol) (PVA). The coating composed of A151 has a relatively uniform and flat surface structure, due to weaker hydrolysis ability of A151 promoted the smooth condensation speed, compared to KH570. Thanks to the hydrophilic and hydrophobic balance properties of the A151-modulated coating network, the resultant coating exhibits good antifogging performance in the range of 0 °C to 90 °C, which keeps a light transmission of about 85 %. Surprisingly, the coating shows excellent adhesion (350–700 kPa) to the substrate, which is significantly better than other conventional hydrophilic antifogging coatings, and the hydrophilic and hydrophobic modulation capability and the enhanced interfacial adhesion of A151 segments provide the basis of the coating for long-lasting antifogging, which would open up a new way of durable hydrophilic antifogging coatings.

Comparison of Coren mix design with other international mix (ACI and DoE) design methods

Because of its quality, which allows for veracities, Today, concrete is the most frequently utilized civil engineering material. Concrete has a low tensile strength and a high compressive strength. Even though Nigeria is Africa's giant, it has been discovered that its local contractor does not have a well-used standard mix procedure. Local Nigerian contractors have relied on an international mix. COREN recently established a mix design. It is critical that we determine whether this design process will be suitable for usage by local contractors. To assess the effectiveness of the published local mix against defined international standards, a complete experimental analysis of the COREN mix design with ACI and DoE was used in this study. With a target compressive strength of 30N/mm2, three concrete mix designs with 0.48 and 0.50 water/cement ratios were used, and this mix was subjected to compressive tests, split tensile tests, and three-point bending. With respect to all the test conducted and analyzed, this attests to the level of significance of COREN i.e. For 28days mix with 0.48w/c, compressive strength with COREN gave 32N/mm2 against 31N/mm2 and 30N/mm2 for ACI and DoE mix, respectively. Splitting tensile strength of 2.7 N/mm2 was achieved with COREN mix against 2.8N/mm2 and 2.7N/mm2 from ACI and DoE, respectively. Likewise, results of flexural strength are 4.7N/mm2, 5.3N/mm2 and 5.1N/mm2 for COREN, ACI and DoE, respectively. For 28days mix with 0.50w/c, compressive strength with COREN gave 29N/mm2 against 30N/mm2 for ACI and DoE mix, respectively. Splitting tensile strength of 2.5N/mm2 was achieved with COREN mix against 2.4N/mm2 and 2.8N/mm2 from ACI and DoE, respectively. Likewise, results of flexural strength are 5.1N/mm2, 4.7N/mm2 and 5.6N/mm2 for COREN, ACI and DoE, respectively.

Optimizing sheet metal edge quality with laser-polishing: surface characterization and performance evaluation

Dual-phase (DP) steels are widely used in the automotive industry due to their exceptional performance. It offers excellent strength, ductility, formability, and weldability. However, there is a high risk of edge cracking, particularly in materials like DP1000 steel, caused by residual damage from blanking, such as microcracks and burrs, which needs further investigation. In this study, the transformative potential of laser-polishing on DP1000 steel was investigated. The goal was to reduce edge crack sensitivity and enhance edge formability. In this work, laser-polished samples produced by various pre-manufacturing techniques such as sawing, punching, and waterjet cutting were examined. Various evaluations were performed on laser-polished samples. Those included white-light-confocal microscopy, scanning electron microscopy, and Electron Backscatter Diffraction (EBSD) analysis. Those evaluations aimed to analyze the microstructural transformation, surface roughness, and micro grain size distribution resulting from laser-polishing. Laser-polishing is a process in which the edge of the sample is remelted locally. Hence, residual damage vanishes, and surface defects disappear, which should be beneficial for edge formability. On the other hand, the cooling rate during re-solidification is high, leading to high strength and reduced ductility compared to the initial DP steel. Therefore, hole expansion tests were conducted to evaluate the edge formability of the steel. The results indicated a significant improvement in the hole expansion ratio of the laser-polished samples compared to samples with conventional manufactured edges. These findings will help to assess the advantages and limitations of laser-polishing in sheet material manufacturing.

Numerical studies on low-temperature eccentric-compression behaviours of UHPC-filled Q690E high-strength steel tubes

This paper numerically studied the compression behaviours of ultra-high performance concrete - filled square high strength steel tubes (UFSHTs) at low temperatures. Firstly, finite element models (FEMs) were developed to simulate the ultimate strength behaviours of UFSHTs under bending and compression, which were extensively validated by bending and compression test results. Then, extensive FEM analysis were carried out to investigate the low-temperature eccentric-compression behaviours of UFSHTs at low temperatures. The studied parameters in this numerical analysis included low temperatures, eccentricities, and slenderness ratios. The FEM parametric studies showed that (1) reducing low temperatures improved the eccentric-compression capacities; (2) The load-displacement curves exhibited a more protracted hardening stage with higher eccentricity ratios; (3) the normalized N-M curves were shrunk inward with slenderness ratios increasing. Finally, modified code equations were proposed to estimate the N-M interactions of UFSHTs under low-temperature eccentric-compressions, and validations of the predictions against the test and numerical results confirmed that the modified Eurocode 4 code equations provided more reasonable estimations than AISC360 and GB50936.

Sustainable solutions for Workable and Strong concrete: Cordia Gel and Waste Engine Oil Admixtures

To produce high strength or rich cement concrete having low water to cement ratio with adequate workability is the biggest challenge for the construction industry. To achieve the necessary workability, the world is now using costly chemical admixtures. Research should be carried out to explore materials having potential to be utilized as costeffective chemical admixtures in concrete. The primary goal of this research is to investigate the combined effect of Cordia Gel (CG) and Waste Engine Oil (WEO) as chemical admixtures on fresh and hardened properties of concrete. Fresh properties of concrete were examined in terms of workability and hardened properties were investigated by compressive strength test and Ultrasonic Pulse Velocity (UPV) test on cubical specimen of dimensions 100mm x 100mm x 100mm after 7, 28 and 90 days of curing in water. Four different percentages of WEO (0.5%, 1%, 1.5% and 2%) were used and percentage of CG kept constant as 0.5% with respect to weight of cement and results were compared with the control mix. Results revealed that workability of fresh concrete increased with increasing amount of CG and WEO. However, a decreasing trend was observed for compressive strength and UPV of hardened concrete when higher values of admixtures were added. The usage of CG and WEO as chemical admixtures in concrete can be a sustainable and cost-effective way to achieve the desired results

Microstructures and mechanical properties of W-Co-Al tungsten heavy alloy prepared by different formation processing

High density, high strength and high susceptibility to adiabatic shear banding (ASB) have always been pursued by tungsten heavy alloys (WHAs) for kinetic energy armor-piercing projectiles. To meet the demand, this work reported a novel tungsten heavy alloy with high-density L12 precipitation-strengthened Co9Al9W binder (WCAW). WCAWs were prepared by liquid phase sintering (LPS) and laser ultrashort-time liquid phase sintering (LULPS) respectively. Experimental results show that LULPS technique with large molten pool convection and rapid solidification can produce WCAWs with uniform W distribution, low W-W contiguity and fine W particles. Conversely, W particles in LPS WCAWs were excessively connected and segregated. The uniform distribution, low W-W contiguity and fine W particles enable LULPS WCAW to exhibit better mechanical properties. The ultimate compressive strength of the LULPS WCAWs is ∼2442 MPa, 16.4 % higher than that of the LPS WCAWs. As well, the dynamic yield strength of LULPS WCAWs is high, which is ∼2281 MPa and 37.4 % higher than that of LPS WCAWs.