Material Selection Criteria Research Articles

Sustainable assessment criteria for airport runway material selection: a fuzzy analytical hierarchy approach

PurposeAirport construction is extremely different than the construction of any other transport infrastructure. It is a vital area affecting both the environment and the economy. Therefore, sustainable selection of building materials represents a very important step. The main objective of this paper was to develop a set of sustainable assessment criteria (SAC) to assist design team members in the selection between two different material alternatives when constructing a new runway in Kuwait international airport. The proposed materials were asphalt or concrete.Design/methodology/approachA set of 24 sub-criteria were developed, those were emerged from three main criteria: technical, environmental and socio-economic. Fuzzy analytical hierarchy process (FAHP) was employed to assign weights and to measure the relative importance of these criteria for the material alternatives selection. The prioritizing process for criteria was based on a survey of 100 responses.FindingsIt had been concluded from the use of FAHP that asphalt material was a better alternative in maintainability, ease of construction, health and safety, initial cost and energy saving. Concrete was better in fire resistance, durability, decay resistance, energy saving and thermal insulation, maintenance cost, aesthetics, minimizing pollution, impact on air quality, low toxicity, environmentally disposal sound system, amount of likely wastage and raw material extraction method.Originality/valueDevelop a set of SAC to assist design team members in deciding between two material alternatives to construct a runway.

Hemocompatibility of polymers for use in vascular endoluminal implants

AbstractImplanted polymers for cardiovascular applications may function as structural supports, barriers, or provide a means for local drug delivery. Several thermoplastic biodegradable drug delivery polymers are potential candidates for blood‐contacting implant applications. For intravascular applications specifically, a criterion for material selection is the intrinsic hemocompatibility of the baseline polymer. As an initial screening approach for selection of polymers for in vivo use, thin films of polyesters: poly(ɛ‐caprolactone) (PCL), poly(lactic acid) (PLA), poly(lactic‐co‐glycolic acid) (PLGA); polyanhydrides: poly(fatty acid dimer‐co‐sebacic acid) (PFAD:SA) and poly(biscarboxyphenoxypropane‐co‐sebacic acid) (PCPP:SA); and poly(ethylene glycol) (PEG)‐ylated polyesters: PLA:PEG, PCL:PEG and PCL:PLA:PEG polymers were spin‐cast on glass cover slips and placed in an in vitro flow system exposing them at a controlled shear to overflowing human whole blood. Platelet adherence, aggregate formation, and thrombus formation, as well as leukocyte adherence were assessed following 5 min of flow. At 5 min of flow the rank order of materials, in terms of least to most thrombogenic was: PCL < PFAD:SA < PCPP:SA < PLGA < PLA. All PEGylated materials, in general, had less thrombus formation than baseline unmodified materials.

Multi-State Heterojunction Transistors Based on Field-Effect Tunneling-Transport Transitions.

A monolithic ternary logic transistor based on a vertically stacked double n-type semiconductor heterostructure is presented. Incorporation of the organic heterostructure into the conventional metal-oxide-semiconductor field-effect transistor (MOSFET) architecture induces the generation of stable multiple logic states in the device; these states can be further optimized to be equiprobable and distinctive, which are the most desirable and requisite properties for multivalued logic devices. A systematic investigation reveals that the electrical properties of the device are governed by not only the conventional field-effect charge transport but also the field-effect charge tunneling at the heterointerfaces, and thus, an intermediate state can be finely tuned by independently controlling the transition between the onsets of these two mechanisms. The achieved device performance agrees with the results of a numerical simulation based on a pseudo-metal-insulator-metal model; the obtained findings therefore provide rational criteria for material selection in a simple energetic perspective. The operation of various ternary logic circuits based on the optimized multistate heterojunction transistors, including the NMIN and NMAX gates, is also demonstrated.

Refractive index and extinction coefficient of hollow microspheres for solar reflection

While hollow microspheres and various porous structures have received much attention for solar reflection in the recent literature, their fundamental determinants of optical properties and material selection criteria are relatively little known. Here, we study hollow microspheres with varying refractive index and extinction coefficient and identify their role in determining the solar reflectivity. Our simulations based on finite-difference time-domain method show the effects of refractive index between 1.5 and 100 and extinction coefficient between 10−6–100 in the wavelength region of 0.2–2.4 μm and explain how the reflectivity of hollow microspheres is attributed to a combination of strong backscattering and limited absorption. Our analysis indicates that ceramic materials with a high refractive index and a low extinction coefficient such as Y2O3 are promising. When Y2O3 hollow microspheres are randomly distributed with the diameter ranging from 0.5 to 1 μm, our simulation shows the solar reflectivity reaches 0.97 even at 300 μm thickness, and a diffusion theory-based model predicts the solar reflectivity to exceed 0.98 at 500 μm or 0.99 at 1 mm thickness. Our findings can guide optimal designs of hollow microspheres and related porous structures toward complete solar reflection and enable breakthroughs in thermal management and deep-space applications.

A Systematic Approach for the Reliability Evaluation of Electric Connector

Under the trend of high density and miniaturization, the current that the connector transmits per unit volume is getting higher and higher, which makes the reliability design of the connector more challenging. Under the pressure of high performance and low cost requirements, the design has to be more accurate and more efficient. Thus, in the design process, a systematic approach for reliability evaluation is required. However, there is no valid enough approach that is integrated, well-organized, and quantitative. In this article, a systematic approach for the reliability evaluation of connector was proposed, and by applying it on a typical object named a blade-spring connector, the validity of this approach was verified. After the framework of this approach has been established, the methods and models needed were provided, including the method to build up material selection criterion and the assessment models of stress relaxation, thermal diffusion, and sliding wear, respectively. Then, the feasibility of a newly developed copper alloy on the connector and the reliability behaviors of this connector were determined through this approach. The unsatisfactory aspects of reliability were pointed out and some possible redesign choices were provided. Results and discussion revealed that the proposed approach is a helpful tool for designing electric connectors, especially on the reliability design.

Research on Multi-criteria Material Selection of Automobile in Full Cycle under the Background of Green Manufacturing

Under the background of the continuous strengthening of green manufacturing, the automobile industry, as a typical representative of the industry, will be an important battlefield for the green development of China’s industry. In addition, with the emergence of new alternative materials for automobiles, the selection range of materials for automobile parts is gradually expanding. Literature from year 2009 until year 2019 were collected which is focused on related automotive material selection. It’s worth noting that the concept of “green manufacturing” was proposed in 2018. It is found that the selection criteria of automobile materials have been expanded from only focusing on mechanical properties to economic performance, technological performance and environmental performance. The multi-attribute material selection method is emerging because of the more complicated material selection caused by the increase of environmental attributes, which also brought manifest divergences in the selection of secondary indicators and the setting of weights. According to the practical application, the optimization measures related on the selection basis of secondary indicators and setting weights from the perspective of producers and consumers in the whole life cycle were proposed.

Performance Assessment of Nano-enhanced Phase Change Material for Thermal Storage

The use of nano phase change material in thermal energy storage applications appears promising, but the often-poor performance and the lack of understanding of the heat transfer mechanisms interconnectedness remains a challenge and hinders their widespread integration. The existing numerical work has unveiled numerous impediments in predicting the actual melting behaviour. They rarely combine the effects of conduction enhancement, convection degradation, and latent heat reduction, due to inaccurate characterization of the thermophysical properties and the limitations of their model assumptions. In the present study, an enhanced numerical approach was developed to investigate the melting performance of xGnP-octadecane filled in a vertical cylindrical enclosure at different weight concentrations. The model results for the pure phase change material were compared and validated against the experimental data. The progression of the melting front, temperature probes, energy storage capacity and heat transfer rate of the nano phase change material were thoroughly evaluated. The current numerical observations demonstrate that the addition of nanoparticles improves, up to a critical concentration of 0.5wt%, the melting rate. The results showed that by adding 0.5wt% of xGnP in the base phase change material (octadecane), the melting rate decreases by 9.7% and the heat storage rate increases by 12.6%. However, at higher loadings, the heat transfer rate is deteriorated due to worsening of other thermophysical properties provoking the prevalence of viscous forces over natural convection and latent capacity. The system overall efficacy was found to be dependent on the net effects of relative changes of all thermophysical properties with nanoparticle concentration and temperature in the solid, so called mushy, and liquid zones. Finally, when characterizing nano phase change material, the thermal conductivity cannot be considered alone as a criterion for nano phase change material selection. A high thermal conductivity is needed for maximum heat absorption in thermal transport applications. Nevertheless, low viscosity, high latent heat and specific heat capacities are also essential to ensure a better thermal energy storage efficiency in terms of capacity and heat extraction/release rate.

Selection Criteria for Building Materials and Components in Line with the Circular Economy Principles in the Built Environment—A Review of Current Trends

A growing concern is given to the environmental impacts caused by the construction industry. Waste generation, resource consumption, and greenhouse gas emissions are the main drawbacks of the rapid urbanization that the world is witnessing. As a response to these pressing issues, policymakers and academia are exploring the concept of Circular Economy (CE) to manage resources better and achieve resource efficiency while eliminating waste. One of the strategies to implement CE in the built environment is to select the appropriate building materials and components from the early stages to carry out the concept’s principles along the value chain and create a closed-loop system. Therefore, this study aims at identifying selection criteria for building elements according to CE principles through a review of the latest research. Results have shown that little has been concretely achieved in terms of a paradigm shift to CE since the main focus of the literature is still the use of recycled products and the recyclability of building materials and components at their end-of-life. Although the present study is solely focused on the technical aspect of building materials and components, it outlines current adopted criteria to bring about a circular built environment and highlights the need for a more innovative approach to attain higher circularity levels.

Embodied Carbon as a Material Selection Criterion: Insights from Sri Lankan Construction Sector

The choice of materials is crucial in responding to the increasing embodied carbon (EC) impacts of buildings. Building professionals involved in material selection for construction projects have a vital role to play in this regard. This paper aimed to explore the extent to which building professionals in Sri Lanka considered EC as a material selection criterion. A questionnaire survey was conducted among a sample of building professionals in Sri Lanka. The results indicated that the consideration of EC as a material selection criterion remained low among key professionals, such as architects, engineers, and sustainability managers, despite their reasonable influencing powers and knowledge of EC. Those respondents who had considered EC as a selection criterion said they had been primarily driven by green building rating systems and previous experience. Those respondents who had not considered EC during material selection commonly reported that they had been prevented from doing so by the lack of regulations and the lack of alternative low carbon materials. Respondents believed that the involvement of actors, such as the government, professional bodies, environmental organizations, activist groups, and the public, may be significant in promoting the greater consideration of EC during material selection.

Screen-Printed Nickel-Zinc Batteries: A Review of Additive Manufacturing and Evaluation Methods.

The advent of personalized wearable devices has boosted the demand for portable, compact power sources. Compared with lithographic techniques, printed devices have lower fabrication costs, while still maintaining high throughput and precision. These factors make thick film printing or additive manufacturing ideal for the fabrication of low-cost batteries suitable for personalized devices. This article provides comprehensive guidelines for thick-film battery fabrication and characterization, with the focus on printed nickel-zinc (Ni-Zn) batteries. Ni-Zn batteries are a more environmental-friendly option compared with lithium-ion batteries (LIBs) as they are fully recyclable. In this work, important battery fundamentals have been described, especially terms of electrochemistry, basic design approaches, and the printing technology. Different design approaches, such as lateral, concentric, and stacked, are also discussed. Printed batteries can be configured as series or parallel constructions, depending on the power requirements of the application. The fabrication flow of printed battery electrodes for the laboratory-scale prototyping process starts from chemical preparation, mixing, printing, drying, pressing, stacking to finally sealing and testing. Of particular importance is the process of electrolyte injection and pouch sealing for the printed batteries to reduce leakage. This entire process flow is also compared with industrial fabrication flow for LIBs. Criteria for material and equipment selection are also addressed in this article to ensure appropriate electrode consistency and good performance. Two main testing methods cyclic voltammetry for the electrodes and charge-discharge for the battery are also explained in detail to serve as systematic guide for users to validate the functionality of their electrodes. This review article concludes with commercial applications of printed electrodes in the field of health and personalized wearable devices. This work indicates that printed Ni-Zn and other zinc alkaline batteries have a promising future. The success of these devices also opens up different areas of research, such as ink rheology, composition, and formulation of ink using sustainable sources.

Die Material Selection Criteria for Aluminum Hot Stamping

The aim of this work is to develop a die material selection criterion for aluminum hot stamping applications. The criterion has been based on the back-to-back comparison of a set of reciprocating friction and wear tests. Three representatives belonging to different stamping die material families have been selected for the study: a cold work steel, a hot work steel, and a cast iron. These tool materials have been combined with an exemplary member from two heat treatable aluminum families: 2XXX and 6XXX. Each die-material/aluminum–alloy combination has been tested at three temperatures: 40, 200, and 450 °C. The temperatures have been selected according to different stamping scenarios: long takt time press quenching, short takt time press quenching, and very short takt time hot forming without quenching, respectively. The results show that, among the three die material options available, the cold work steel turned out to be the most favorable option for high volume production and long takt time, the hot work steel fitted best for high volume production coupled with short takt time, and cast iron turned to outstand for short runs with prototype dies and for hot stamping without die quenching.

Thermoplastic Polymer Selection for Optimal Thermal Efficiency of Composite Syrup Vessel

Material selection is one of the vital and critical steps in the mechanical design process. In recent times, various tools based on the multi-criteria decision-making process are used successfully to cope with such complexity in material selection. .This work provides appropriate methods and tools to find the optimum thermoplastic polymer reinforced natural fiber composites. The material selection applied using a decision-making model that consists of the „Technique for Order of Preference by Similarity to Ideal Solution“ (TOPSIS) and „Vlsekriterijumska Optimizacija I Kompromisno Resenje“ (VIKOR) methods in order to rank of the materials according to applied criteria. Analytical Hierarchy Process (AHP) method was performed in order to determine the weighting of the material properties or criteria. Rank the materials were gained by using ranking scores as results of the methods use. The results offer that the best polymers were found to be the LDPE and Nylon 6,6. It was proved that the multi-criteria decision-making model is an application for solving complex material choice decision problems. This model can be applied to other engineering applications with any number of alternatives and criteria for material selection.

Text selection criteria for testing and assessment materials used at the Russian language unified state examination

Text selection criteria for testing and assessment materials used at the Russian language unified state examination

Specifics of forming linguistic sociocultural competence among foreign students in the pre-university p

The article considers communicative competence as a sum of several competences such as linguistic, paralinguistic, linguistic-sociocultural, substantial competences, etc. Linguistic sociocultural competence is specifically featured. The article describes linguistic cultural, psychosocial and cultural expertise and skills. The criteria of learning material selection for the formation of linguistic sociocultural competence.

Examining the Selection and Use Criteria of Digital and Non-Digital Materials of Teachers

Öğrenme süreçlerinde öğretim materyalleri önemli bir yere sahiptir. İçinde yaşadığımız dijital çağda dijital materyallerin kullanımı önemli olmakla birlikte, dijital olmayan materyaller de etkin bir şekilde kullanılmaktadır. Buna karşın dijital materyallerin daha önemli olduğu şeklinde yanlış bir algı bulunmaktadır. Bu araştırmada dijital ve dijital olmayan materyallerin seçimi ve kullanımı aynı öğretmen görüşleri ile değerlendirilmiştir. Bu kapsamda 42 sınıf öğretmeninin eğitim öğretim süreci içerisinde dijital veya dijital olmayan materyalleri seçim ve kullanım kriterleri araştırılmıştır. Araştırma nitel bir çalışmadır ve durum çalışması desenindedir. Araştırma sonucunda, öğretmenlerin okullarında dijital kaynaklara sahip oldukları, bu dijital kaynakları dersin her aşaması, konunun gerektirdiği önemli bir anda, konu anlatımı sırasında, dersin sonu veya başı gibi aşamalarda kullandıkları görülmüştür. Öğretmenler materyal seçimi konusunda en çok öğrenim gereksinimleri ile öğrenci durumlarını ön plana çıkarmışlardır. Sağladığı avantajlar açısından dijital olmayan materyaller anlatım ve anlama kolaylığı, yaparak yaşayarak öğrenme gibi özellikleri ile ön plana çıkarken, dijital materyaller ilgi ve dikkat çekme, çoklu ortam desteği, ekonomik olma gibi özellikleri ile ön plana çıkmıştır. Dezavantajları açısından incelendiğinde ise öğretmenler dijital olmayan materyalleri bireyselleştirememe, tasarım ve kullanım zorluğu, maliyet gerektirme, yıpranma gibi yapısal ve fiziksel özellikleri ile, dijital materyaller açısından ise kolaycılık ve tembelliğe sebep olma, bağımlılık gibi olumsuz davranışlara yatkınlık özellikleri ile ifade etmişlerdir.

Harnessing Interfacial Electron Transfer in Redox Flow Batteries

Summary Redox flow batteries (RFBs) have garnered increasing attention for their potential to enable the widespread adoption of renewable electricity. However, a critical need associated with the continued development of this technology involves designing electrode-electrolyte interfaces that exhibit rapid, stable electron transfer kinetics. This targeted review outlines key challenges associated with measuring and enhancing the electron transfer kinetics of established and emerging flow battery active materials. We discuss several promising opportunities for advancing flow battery science and technology using the tools of applied electroanalysis and catalysis science. These challenges and opportunities are broadly relevant for future research directed at advancing the commercial adoption of RFBs for grid-scale energy storage.

Indirect Evaporative Cooling: An Efficient and Convenient Energy System

Evaporative cooling is now an alternative method for the conventional air cooling method. This method does not only save energy but also protect the environment from global warming and hazardous gases. Thus this system is highly efficient and eco-friendly. Evaporative cooling system is further divided into two categories that are direct evaporative cooling system and an indirect evaporative cooling system. The direct evaporative cooling system is not much efficient due to high wet bulb temperature and moisture thus rather than using the direct evaporative cooling system the indirect evaporative cooling system is preferred. This paper discusses comparative studies of performance, working principles, material selection criteria’s and various methods. It also explains the performance under different weather conditions, hybrid structure to reduce the load on the further system. It summarises various aspects like wick attained aluminium sheet is the best material for IEC or counter-flow heat exchanger is effective than parallel-flow heat exchanger. It finally results that indirect evaporative cooling system is moisture free, very effective and environment savings. That can be used in various residential and commercial sectors effectively as an alternative for conventional energy-consuming system.

Grouting for water and mud inrush control in weathered granite tunnel: A case study

This paper presents a case study of curtain grouting to prevent water and mud inrush disasters for a weathered granite tunnel in Guangxi, China. First, the basic information of the Junchang tunnel is given, including ground conditions, water and mud inrush disasters, and the subsequent prevention countermeasures. Then, we present the original grouting design and procedure, and the field operation of 25 grouting cycles and excavations for the evaluation of the grouting effect and suggestion for future grouting work. Based on the field investigation, the values of the major grouting parameters are suggested, including grouting thickness of 5– 8 m, grouting length of 15– 18 m (3– 3.6 times of thickness), and per-meter grouting volume of 34.2 m3. Furthermore, the guidelines for composite materials selection are proposed for the various flowing water environments. Moreover, the space positions and water quality of the inspection boreholes and the original water richness of the ground should be taken into consideration in the grouting evaluation criteria. The optimized grouting parameters, materials selection and evaluation criteria provide important references for disasters prevention in similar projects.

Nanocomposite Membranes for Liquid and Gas Separations from the Perspective of Nanostructure Dimensions.

One of the critical aspects in the design of nanocomposite membrane is the selection of a well-matched pair of nanomaterials and a polymer matrix that suits their intended application. By making use of the fascinating flexibility of nanoscale materials, the functionalities of the resultant nanocomposite membranes can be tailored. The unique features demonstrated by nanomaterials are closely related to their dimensions, hence a greater attention is deserved for this critical aspect. Recognizing the impressive research efforts devoted to fine-tuning the nanocomposite membranes for a broad range of applications including gas and liquid separation, this review intends to discuss the selection criteria of nanostructured materials from the perspective of their dimensions for the production of high-performing nanocomposite membranes. Based on their dimension classifications, an overview of the characteristics of nanomaterials used for the development of nanocomposite membranes is presented. The advantages and roles of these nanomaterials in advancing the performance of the resultant nanocomposite membranes for gas and liquid separation are reviewed. By highlighting the importance of dimensions of nanomaterials that account for their intriguing structural and physical properties, the potential of these nanomaterials in the development of nanocomposite membranes can be fully harnessed.

A Material Selection Criterion for Electrostatic Switches Based on Stability Considerations

Recent impressive advances of MEMS technology thanks to integration of emerging materials exhibiting exclusive properties, has led to fabrication of numerous high performance devices. Further development of the field necessitates more accurate analytical models capable of precisely accounting for all existing physical phenomena affected by new materials properties. In this regard, the present paper investigates how finite electrical conductivity of the composing materials may affect the pull-in instability of an electrostatically actuated cantilever MEMS switch. The governing coupled nonlinear equations of an equivalent lumped parameter model are derived by introducing an assumed mode solution to the extended Hamilton’s principle. A Lyapunov-based method is then employed to derive an estimation for the basin of attraction of the stable equilibrium and determine the minimum voltage needed for the cantilever to escape the attractor and touch the contact. Results indicate the substantial effect of electrical resistivity on both instability range and maximum switching frequency of the device. As evidenced by the presented findings the material selection for this type of switches should be made with a broader view bringing into focus the effect of electrical conductivity of the material on stability characteristics of the device.