Material Options Research Articles

Preparation and Properties of Shape Memory PEG/IEM Resin and Its Composite Designed for Ureter Stent.

In this paper, isocyanoethyl methacrylate (IEM) is used to functionalize the two ends of poly(ethylene glycol)(PEG) diol with acrylic acid groups through an urethanisation reaction. The synthesized PEG/IEM resin is then photo-cured with a 405nm ultraviolet lamp. Ttrans of the PEG/IEM resin can be regulated by the different molecular weights of PEG and the use of plasticizer Triacetin to reach 44°C, which is closer to the human body temperature. Cytotoxicity assay and DMA shape memory cycling testing show that the PEG/IEM resin has excellent biocompatibility and shape memory properties. The flower structure is prepared and its shape recovery process is demonstrated. The performance of 10wt% nano Fe3 O4 /PEG4000/IEM resin and its composite spring stent structure satisfy the requirement of the stent properties in vivo, and can quickly recover to the original shape under magneticallydriven. This work provides a material option for developing new biological application devices such as ureter stents. This article is protected by copyright. All rights reserved.

Ultra-high Performance Concrete as a Sustainable Structural Composite

The phenomenal strides in the modifications and the use of supplementary cementitious materials in conjunction with superplasticizers and discrete fiber distributions in concrete made it possible to arrive at the structural material termed as “ultra-high performance concretes” (UHPC) or its extension “ultra-high performance fiber reinforced concretes” (UHPFRC). Its development heralded a new era, opening new vistas in structural configurations and forms that could be a serious contender to structural steel constructions. Primarily, the chemistry and physics of concrete constituents and mixture design philosophy have not changed much, though the intricacies that are often neglected were effectively corrected from time to time. The use of materials ranging from the conventional to nanoparticles that could exhibit superior pozzolanic activity along with microfibers resulted in strengths well beyond 200 MPa. This opens up several avenues in structural configurations that are of high strength and durability. However, this isn’t a stipulation of replacing the present-day concrete in all structures with UHPC, but the key is to modulate the structural configurations to suit the needs of the particular application for ensuring sustainability in consonance with the capabilities of UHPC. The paper attempts to look at the possible avenues for such options in materials and structural forms to effectively assure sustainable construction alternates.

A Comprehensive Modeling Platform for Interconnect Technologies

With device scaling facing major physical and manufacturing challenges, many research efforts have been focused on the impact of device parameters and designs on circuit performance and power dissipation. However, similar research on the impact of Cu-low <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> interconnects at the advanced nodes and the potential benefits offered by novel wire and via material and process options is lacking. While studies based on smaller circuit blocks exist, the exploration of these benefits for the performance of larger processors is lacking although the limits imposed by interconnect resistances become more severe due to longer wires and increased complexity in larger circuits. In this article, we conduct a study to quantify the effect of back-end-of-the-line (BEOL) technology improvements on circuit power, performance, and area (PPA) of various circuits from small blocks up to a full commercial processor with L1-cache. We modified the interconnect technology (ICT) files for the ASAP7 process design kit (PDK) to reflect various BEOL options such as thinner barrier/liners, near barrierless vias, and alternative material options based on TCAD simulations. We show that these options can offer up to a 1.769 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> improvement in effective frequency or up to three metal-level savings.

Revealing the adhesion, stability, and electronic structure of SiC/M (M=Au, Pt) interface: A first-principles study

The interface bonding and electronic properties between SiC and metal are the key factors affecting the physical transport phenomena of metal-semiconductor field-effect transistors (MESFETs). The work of adhesion, interface energy and electronic structure of SiC/M (M = Au, Pt) interface are explored by first-principles method. Forty possible interface models were constructed for different surfaces and stacking positions, and the four most stable interfaces were screened based on the work of adhesion and interface energy. Moreover, the interfacial bonding behavior and strength of SiC/M were quantitatively and qualitatively described through partial density of states (PDOS), crystal orbital Hamilton population curves (COHP), and charge density distribution (CDD). The PDOS demonstrated covalent bond characteristics between M − Si and M − C, which are primarily bonded by M-d and Si-p or C-p orbital hybridization. Further, the COHP and CDD analyses clearly manifested that the Pt–C bond at the interface exhibits more pronounced electron aggregation and greater bonding strength than the Au–C bond. This study offers a comprehensive understanding of the interfacial bonding strength between SiC and Au or Pt and demonstrate that SiC/Pt contact is the more favorable option for electronic device materials.

Optimization of the dilution parameters to improve wear resistance of laser cladding 15-5PH steel coating on U75V pearlitic steel

The dilution effect of the substrate during laser cladding is inherent, and controlling the dilution degree paves the way for the microstructural design of coatings with excellent mechanical properties. In this study, low-carbon 15–5 precipitation hardening (PH) stainless steel was selected as the cladding material on the surface of U75V pearlitic railway steels to improve wear performance. By altering the processing parameters, the cracking susceptibility, microstructures, and wear resistance of coatings with different dilution rates were investigated thoroughly. The results indicated that with the increase of laser beam power, the dilution effect of the eutectoid steel substrate enhanced obviously, resulting in the composition deviation of coatings. Microhardness of the coatings increased with the dilution rate but the excessive dilution effect led to severe cracking defects. The optimized cladding coating with a dilution rate of about 48 % exhibited a microhardness of 490 HV, and the wear tests showed that the wear volume decreased by about 85 % when compared to that of the U75V substrate. Microstructural characterization revealed that the increased carbon content induced by dilution, resulting in martensite hardening and carbides precipitation, was responsible for these performance improvements. This work demonstrated the potential of coating strengthening by dilution control, which expands the option for surface modification materials for railways.

Structural optimisation for controlled deflections of additively manufactured single material beams

Closely controlling the mechanical behaviour and characterization of the deflection of a beam structure is a well-known and widely studied engineering problem. The progress in additive manufacturing methods and the possibilities to closely control the material property variations with the controlled placement of materials further widen the opportunities to achieve given beam deflection criteria. The multi-material additive manufacturing solutions suffer from the lack of real engineering material options, and the quality and performance of the printed parts are usually unsuitable for producing functional parts. A novel cellular structured solution is proposed here, which utilises optimisation of geometries of individual cells of a single material structured beam to obtain deflection profiles closely matched with preset conditions under different loading conditions. The cellular geometry of the structured beam is continually altered for searching and converging on the optimal structure of the cells by the covariance matrix adaptation evolution strategy algorithm in an iterative manner. The optimised beam structures could also be physically produced with single material additive manufacturing methods and the experimental and numerical beam deflection responses correlated closely.

Functional insights to the development of bioactive material for combating bacterial infections.

The emergence of antibiotic-resistant "superbugs" poses a serious threat to human health. Nanomaterials and cationic polymers have shown unprecedented advantages as effective antimicrobial therapies due to their flexibility and ability to interact with biological macromolecules. They can incorporate a variety of antimicrobial substances, achieving multifunctional effects without easily developing drug resistance. Herein, this article discusses recent advances in cationic polymers and nano-antibacterial materials, including material options, fabrication techniques, structural characteristics, and activity performance, with a focus on their fundamental active elements.

Effect of heat treatments on the wear resistance of HVAF and HVOF sprayed tool steel coatings

Iron-based coatings are an attractive solution for many wear applications, considering sustainability requirements such as avoidance of critical raw materials and toxic substances. Cold worked tool steels are one potential, yet very undiscovered, material option for coating applications. As a bulk, their careful heat treatment typically produces a martensitic carbide microstructure with very good wear resistance. Compared to bulk materials, the thermal history of a thermally sprayed coating in the as sprayed state is quite different as the microstructure of the sprayed coating does not form in equilibrium. This study explored the potential of AISI D2 cold worked tool steel as a thermal spray coating under different wear conditions. The study investigated different heat treatments to achieve different microstructures of the powder and coatings and their effect on the wear and cavitation erosion properties of the HVOF and HVAF sprayed thermally sprayed tool steel coating. It is important to understand whether the properties of thermally sprayed coatings, which initially have a high defect density, can be improved by heat treatments, and how modification of the phase structures of iron-based coatings affects their properties, in order to extend the use of these coatings.

Multi-objective optimization of a liquid metal cooled heat sink for electronic cooling applications

Recently, studies on the use of MCHS applied to chips to benefit from the high thermal conductivity of liquid metals have been increasing. This study came up with an optimum choice for MCHS geometric parameters, MCHS material, Gallium-based liquid metal coolant type, and coolant inlet velocity. Total thermal resistance (Rtot), initial investment cost (Ci), pressure drop (ΔP), and maximum operating temperature (Tmax) are selected as performance parameters. I-optimality algorithm used for generation of the Design of Experiment (DoE) based on the Response Surface Method. The optimization parameters and their levels are determined by performing a parametric study. The derived mathematical models for selected performance parameters Rtot, Ci, Tmax, and ΔP, which are also objective functions, are tested by ANOVA with prediction accuracy of 0.983%, 0.997%, 0.886%, and 0.996%, respectively. As a result, the determined optimum values of the channel width, channel height, half of fin width, fin slope angle, and inlet velocity, are 1.16 mm, 3.00 mm, 0.24 mm, 5.96°, and 0.4 m s−1, respectively. In addition, a hybrid structure in which the base of the designed MCHS is aluminum, and the fins are copper, and the GaIn compound for the coolant are calculated as the optimum material options.

The effects of industrial policymaking on the economics of low-emission technologies: the TRANSid model

Basic materials such as steel, cement, aluminium, and (petro)chemicals are the building blocks of industrialised societies. However, their production is extremely energy and emission intensive, and these industries need to decarbonise their emissions over the next decades to keep global warming at least below 2 °C. Low-emission industrial-scale production processes are not commercially available for any of these basic materials and require policy support to ensure their large-scale diffusion over the upcoming decades. The novel transition to industry decarbonisation (TRANSid) model analyses the framework conditions that enable large-scale investment decisions in climate-friendly basic material options. We present a simplified case study of the cement sector to demonstrate the process by which the model optimises investment and operational costs in carbon capture technology by 2050. Furthermore, we demonstrate that extending the model to other sectors allows for the analysis of industry- and sector-specific policy options.

Thermocline in packed bed thermal energy storage during charge-discharge cycle using recycled ceramic materials - Commercial scale designs at high temperature

ReThink Seramic – Flora is an innovative ceramic material made from 100 % recycled materials. Due to its affordability, suitable thermal performance, and low pressure drop in packed bed thermal energy storage (TES), it is considered as a promising storage material option for high-temperature TES applications including concentrated solar power (CSP) plants. In the present study, a validated CFD model is used to analyze the thermal performance of the sustainable ceramic at high temperature (1000°C) for a commercial-scale packed bed. The paper focuses on modeling the charging/discharging processes and cyclic behavior based on threshold temperature, where dispersion thermal conductivity was considered. The effective thermal conductivity is affected when the dispersion thermal conductivity and the radiation heat transfer are taken into account in the model. The addition of dispersion conductivity leads to a variation in effective thermal conductivity in the range of 28.9–39.9 (W/m.K) for temperature range of 0–1000°C, while the addition of radiation heat transfer leads to a small variation in effective thermal conductivity based on two correlations from literature. The results show excellent thermal performance, with thermal exergy efficiency of 88 % for a full charge/discharge cycle. The net exergy efficiency for seven repeated cycles increased from 73.4 to 88.7 %, where thermal and pressure drop exergy losses are considered. The performance of ReThink Seramic – Flora is compared to the one of a commercial alumina-based TES material product. Thermal exergy efficiency for alumina is higher; however, the alumina-based product showed high pressure drop losses, leading to lower net exergy efficiency.

Study of Metal Leaching from Printed Circuit Boards by Improved Electrochemical Hydrochlorination Technique Using Alternating Current

This paper presents the results of the leaching of metals from computer PCBs by electrochemical hydrochlorination using alternating current (AC) with an industrial frequency (50 Hz). Leaching was carried out with a disintegrator-crushed computer motherboard with a particle size (d) of &lt;90 μm. In the course of the research, the leaching efficiency of metals including Fe, Sn, Mn, Al, Cu, Zn, Pb, Ni, Ti, Sb, Cr, Co and V was evaluated depending on process parameters, such as AC density, experiment duration, hydrochloric acid concentration in the electrolyte solution, solid/liquid ratio, electrolyte temperature, and the loading option of raw material (loading option 1 involving loading into the electrolyte solution, and loading option 2 involving loading into the filter containers attached to electrodes). The research results showed that AC superimposition significantly intensifies the leaching of metals. It was established that the complete leaching of metals including Al, Mn, Sn, Ti and Zn, under experimental conditions (loading option 2, CHCl = 6 mol·L−1, i = 0.80 A·cm−2, S/L = 8.6 g·L−1), is reached after 1.5 h, and that of Cu and Ni is reached after 2 h from the beginning of the experiment. At the same time, the degree of leaching of other metals after 2 h is Co-78.8%, Cr-84.4%, Sb-91.7%, Fe-98.9%, V-98.1% and Pb-5.1%. The paper also reports the results on the leaching of all abovementioned metals, as well as Ag and Pd, with disintegrator-crushed mixed computer PCBs with d &lt; 90 μm and loading option 1.

Phosphomolybdic acid embedded into biomass-derived biochar carbon electrode for supercapacitor applications

In high-performance, clean, safe, and cost-effective ways, supercapacitors are among the most promising ways to store and release nonfossil energy. In recent years, renewable biomass-derived activated carbon has been explored as a potential option for electrode material. It restricts their specific capacitance despite being environment-friendly and possessing intrinsic mechanical strength. In order to overcome this limitation and preserve all other properties, we are infusing polyoxometalate into the activated carbon; this increases specific capacitance with its fast reversible redox behaviour and preserves the carbon’s characteristics. Beside suffusing phosphomolybdic acid (PMA) into biomass waste material, such as orange peel-derived activated carbon (OPAC), a new hybrid material (OPAC-PMA) was developed. The nanohybrid design was revealed by structural and morphological research, which showed high interfacial contact, allowing polyanions to redox rapidly. The novel hybrid electrode material (OPAC-PMA) has a capacitance value of 66% higher than the bare OPAC electrode. A further study showed that OPAC-PMA composite showed 88.23% cycle stability in 0.5 M H2SO4 electrolyte at 6 A g−1 for 4000 cycles.

Polycrystalline Diamond as a Potential Material for the Hard-on-Hard Bearing of Total Hip Prosthesis: Von Mises Stress Analysis.

Due to polymeric wear debris causing osteolysis from polymer, metal ions causing metallosis from metal, and brittle characteristic causing fracture failure from ceramic in the application on bearing of total hip prosthesis requires the availability of new material options as a solution to these problems. Polycrystalline diamond (PCD) has the potential to become the selected material for hard-on-hard bearing in view of its advantages in terms of mechanical properties and biocompatibility. The present study contributes to confirming the potential of PCD to replace metals and ceramics for hard-on-hard bearing through von Mises stress investigations. A computational simulation using a 2D axisymmetric finite element model of hard-on-hard bearing under gait loading has been performed. The percentage of maximum von Mises stress to respective yield strength from PCD-on-PCD is the lowest at 2.47%, with CoCrMo (cobalt chromium molybdenum)-on-CoCrMo at 10.79%, and Al2O3 (aluminium oxide)-on-Al2O3 at 13.49%. This confirms that the use of PCD as a hard-on-hard bearing material is the safest option compared to the investigated metal and ceramic hard-on-hard bearings from the mechanical perspective.

Accelerated carbonation of one-part sodium carbonate-activated slag cements modified by calcined dolomite

One-part or ‘just add water’ alkali-activated material is one promising option of the clinker-free cementitious material being actively researched as the alternative to traditional Portland cements for lowering the energy consumption and CO2 emission involved in the clinker production. The one-part sodium carbonate (Na2CO3)-calcined dolomite (CD)-activated slag cements were developed in this work. The CD additions were effective in shortening the setting times and meanwhile enhancing the compressive strengths of the binders. The carbonation resistance was investigated under accelerated carbonation protocols at 3.0 ± 0.2% CO2. The CD additions slowed down the kinetics of carbonation. Although the binders still underwent the pore structure degradation, the reactive CaO and MgO supplied by CD promoted the formation of calcium hemi-carboaluminate and hydrotalcite-like phase, which had the layered double hydroxide structure with the anion exchange capacity for binding the ingressive CO32− ions. Therefore, the CD addition should be recognized as a novel approach for improving the carbonation resistance of such one-part Na2CO3-activated slag material.

Ni0.6Zn0.4O Synthesised via a Solid-State Method for Promoting Hydrogen Sorption from MgH2

Magnesium hydrides (MgH2) have drawn a lot of interest as a promising hydrogen storage material option due to their good reversibility and high hydrogen storage capacity (7.60 wt.%). However, the high hydrogen desorption temperature (more than 400 °C) and slow sorption kinetics of MgH2 are the main obstacles to its practical use. In this research, nickel zinc oxide (Ni0.6Zn0.4O) was synthesized via the solid-state method and doped into MgH2 to overcome the drawbacks of MgH2. The onset desorption temperature of the MgH2-10 wt.% Ni0.6Zn0.4O sample was reduced to 285 °C, 133 °C, and 56 °C lower than that of pure MgH2 and milled MgH2, respectively. Furthermore, at 250 °C, the MgH2-10 wt.% Ni0.6Zn0.4O sample could absorb 6.50 wt.% of H2 and desorbed 2.20 wt.% of H2 at 300 °C within 1 h. With the addition of 10 wt.% of Ni0.6Zn0.4O, the activation energy of MgH2 dropped from 133 kJ/mol to 97 kJ/mol. The morphology of the samples also demonstrated that the particle size is smaller compared with undoped samples. It is believed that in situ forms of NiO, ZnO, and MgO had good catalytic effects on MgH2, significantly reducing the activation energy and onset desorption temperature while improving the sorption kinetics of MgH2.

Analysis of Bagasse Cellulose-Based Hydrogel for Methylene Blue Removal from Textile Industry Wastewater

The textile industry is one of the biggest water consumption production areas and its waste is essential to cause ecological contamination as they deliver questionable color, weighty metal, and degradable natural and inorganic results whenever arranged without treatment. The natural treatment strategy is not broadly drilled because of its intricate method. In the adsorption method, for example, actuated carbon was limited by prudence of its significant expense and low adsorption limit. This study has completed the combination and portrayal of bagasse cellulose-based hydrogel for the expulsion of methylene blue color from textile industry wastewater. The study furnishes a major critical contributing option for biodegradable adsorption material by supplanting the conventional color evacuation method with a nonconventional one that showsthe attainability of horticultural waste for a union of the hydrogel as opposed to noninexhaustible petrochemical based and show the capability of involving hydrogel for the expulsion of harmful contamination from the textile industry. The hydrogel was combined utilizing free extreme polymerization that can utilize acrylic corrosive (AA) and citrus extract as cross-connecting specialists and monomers individually. FTIR, XRD, and conduct metric titration are the primary hardware utilized for the portrayal of the hydrogel. The cycle boundaries that can influence the color evacuation proficiency of hydrogel, for example, pH, contact time, and temperature have been examined. A focal composite plan by rotatable component is the technique used to browse reaction surface strategies to control the tests with the communication of cycle boundaries.

Delivering Sustainable Housing through Material Choice

Increasing importance is being placed on sustainability worldwide to limit climate change’s effects. In New Zealand, a sizeable increase in demand for housing is driving a residential construction boom, with new dwelling consents increasing yearly for the last decade. The New Zealand Government’s commitment to sustainability has become legislation through the Climate Change Response (Zero Carbon) Amendment Act 2019. Therefore, the next stage is how the construction industry can limit and reduce its carbon emissions through one of the strategies, namely material choice. This study was intended to examine the influence of various building materials on climate change and to identify how more sustainable home construction and design in New Zealand may contribute to the government’s 2050 emissions reduction targets. A life-cycle assessment (LCA) was used in this study to investigate the global warming potential (GWP) produced by five case study houses and various material options for building envelope components. The study focused on the environmental impact of materials with high usage in industry and potential new materials that have shown an ability to conform to the New Zealand Building Code standards. It was found that case study House 1 (with timber flooring founded on senton piles with concrete footings, a timber frame, plywood wall cladding, and metal roof cladding) and House 2 (with a concrete waffle slab, a light steel frame, masonry wall cladding, and metal roof cladding) had the lowest GWP emissions compared to the other case study houses, with 631.13 and 633.16 kg CO2eq/m2, respectively. However, it should be noted that all the case study houses were not similar in size and design. In addition, the study investigated the different building envelope material options for the foundation, wall cladding, framing, and roof cladding. The study found that some new materials or materials that are not common in New Zealand could be used as an option for the housing envelope by having lower carbon emissions, such as 3D-printed concrete blocks compared with brick and concrete masonry for wall cladding systems.

Experimental investigation of concrete prepared with waste rubber and waste glass

Waste rubber (WR) and waste glass (WG) have long been a waste disposal challenge. In an effort to alleviate the environmental impacts of solid wastes and to recycle as much as possible, and extensive research has been carried out to use these wastes as a feasible option for concrete materials. However, the utilization of these potential solid wastes in concrete has not yet obtained popularity. Hence to accomplish this aim of wider application of waste materials in producing concrete, the concrete prepared with this wastes should maintain satisfactory performance. This study investigated the effect of incorporating various substitution levels of WR and WG on the performance of concrete, both separation and in combination. The rubber aggregate was substituted for 10%, 20% and 30% of the sand and glass aggregate was used to replace coarse aggregate at 10%, 20% and 30%, on volume basis. The basic properties were evaluated by conducting workability, compressive strength, split-tensile strength, ultrasonic pulse velocity (UPV), water absorption and sorptivity tests on different forms of the mixtures. Further, the microstructure was analyzed by means of scanning electron microscopy (SEM). The results demonstrated improvement in the water permeability and water absorption of the concrete by adding both rubber and glass simultaneously. In addition, it also showed that the combination of WR and WG enhanced the strengths of rubber concrete, especially at 10% WR and 20% WG. Moreover, the rubber concrete with the addition of glass particles had more encouraging slump results with respect to plain rubber concrete and control mix.

A Hybrid Multi-Criteria Decision Support System for Selecting the Most Sustainable Structural Material for a Multistory Building Construction

In recent years, the performance of the construction industry has highlighted the increased need for better resource efficiency, improved productivity, less waste, and increased value through sustainable construction practices. The core concept of sustainable construction is to maximize value and minimize harm by achieving a balance between social, economic, technical, and environmental aspects, commonly known as the pillars of sustainability. The decision regarding which structural material to select for any construction project is traditionally made based on technical and economic considerations with little or no attention paid to social and environmental aspects. Furthermore, the majority of the available literature on the subject considered three sustainability pillars (i.e., environmental, social, and economic), ignoring the influence of technical aspects for overall sustainability assessment. Industry experts have also noted an unfulfilled need for a multi-criteria decision-making (MCDM) technique that can integrate all stakeholders’ (project owner, designer, and constructor) opinions into the selection process. Hence, this research developed a decision support system (DSS) involving MCDM techniques to aid in selecting the most sustainable structural material, considering the four pillars of sustainability in the integrated project delivery (IPD) framework. A hybrid MCDM method combining AHP, TOPSIS, and VIKOR in a fuzzy environment was used to develop the DSS. A hypothetical eight-story building was considered for a case study to validate the developed DSS. The result shows that user preferences highly govern the final ranking of the alternative options of structural materials. Timber was chosen as the most sustainable option once the stakeholders assigned balanced importance to all factors of sustainable construction practices. The developed DSS was designed to be generic, can be used by any group of industry practitioners, and is expected to enhance objectivity and consistency of the decision-making process as a step towards achieving sustainable construction.