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<jats:p xml:lang="en">Functionally graded materials are composite materials used to build a variety of structures. These structures are used in ships industries, marine, automotive, high building structures, energy engineering applications, and many more. The porosity made in these materials may negatively affect some behavior aspects like stiffness, and strength, but it may provide superior performance in other fields like vibration reduction, thermal isolation, energy absorption, and others. In this paper, we will discuss the effect of porosity on the natural frequencies for functionally graded porous (FGP) sandwich beams. The mechanical properties of the FGP sandwich beams are changing with the porosity in the thickness direction. The free vibration of the beams is examined with the effect of porosity. The analysis is carried out for four different beam supporting types (hinged – hinged, fixed – fixed, fixed – free, fixed – hinged). Various porosity ratios are considered with a range from (0.1 – 0.9). Forty–four samples are analyzed for each type of core material distribution which is the symmetric material constitutive relationships (SMCR) and uniform core material. The results gained from the analysis show that the porosity constant has a significant effect on the natural frequencies of the FGP sandwich beams.</jats:p>

<jats:p xml:lang="en">In recent years, there has been a surge in interest in developing novel materials for sustainable building construction made from renewable resources. The use of natural fibers in concrete reinforcement, as opposed to agricultural waste, has significant environmental benefits in terms of reducing the environmental repercussions of the continuous dumping and landfilling of massive amounts of agricultural waste in overburdened landfill sites. Banana peel fiber (BPF) and orange peel fiber (OPF) are common agro-wastes with a long history of use in concrete as an additive or a cement substitute. However, their efficiency and performance in terms of reinforcement must be assessed. The characteristics, fresh and hardened state structural performance of BPF and OPF as composite materials in sustainable concrete manufacturing are reviewed in this study based on recent findings. For quality concrete reinforcing, it was discovered that OPF and BPF have good surface areas and low specific gravity. For quality concrete reinforcing, it was discovered that OPF and BPF have good surface areas and low specific gravity. BPF and OPF, on the other hand, have significant pozzolanic binding properties of up to 97.3 %. This allows them to act as binders and supplement the high strength yielding in concrete. Furthermore, the use of BPF in concrete enhanced workability, consistency, compressive and tensile strengths, and setting times by 21.1 %, 48.64 %, 46 % and 52.5 %, and 47.37 %, respectively, whereas the use of OPF raised concrete density by 5.34 %. This indicated that both BPF and OPF had a lot of potential for producing high-quality concrete. The use of BPF and OPF to reinforce concrete and composites against flexural deflection, heat transmission, and modulus of elasticity resulted in a significant increase in concrete strength in terms of cracking, deflection, creep, and shrinkage. The inclusion of orange and banana peels in concrete was found to significantly improve the structural qualities of the concrete; thus, they can be employed as supplementary materials in the manufacturing of concrete. Finally, this study identifies new approaches for achieving the much-anticipated biodegradability and sustainability of natural fiber-reinforced composites for usage in a variety of concrete reinforcing applications.</jats:p>

<jats:p xml:lang="en">Vermiculite exfoliation is based on the principle when water between the layers evaporate, and the crystal layers spread out pressured by the steam. As a result, elongated, curved particles are formed. The thermal properties of the final product formed are directly related to this exfoliation amount. In this experimental work, exfoliation characteristic of natural vermiculate is studied. A series of experimental analyzes were carried out to examine the expandability of natural vermiculite at different heating temperatures by the Na+ modification method. In addition, the expansion ratios of Na+-modified and unmodified vermiculite samples were analyzed comparatively. Each of the raw and Na+ modified vermiculite material groups prepared for the thermal expansion process was experimentally performed by recording the exfoliation states and times at six different heating temperature values of 350 oC, 450 oC, 530 oC, 620 oC, 710 oC and 840 oC, respectively, in a laboratory environment. In the second phase of the study, thermal properties of new generation composite mortars produced with exfoliated vermiculite aggregate were experimentally analyzed. Parameters such as thermal conductivity, heat storage capacity, specific heat and heat dissipation coefficient of mortar test samples prepared with exfoliated vermiculite aggregates are analyzed and discussed here. Test results showed that Na+-modified vermiculite samples expanded better than unmodified vermiculite samples for all expansion temperatures. When Na+-modified expanded vermiculite is evaluated in composite mortars, it also reduces the unit weight of the mortar as it expands more and the unit weight of itself decreases. Accordingly, the compressive strength of the mortar decreases relatively. However, it has been determined that the thermal comfort properties of mortars using Na-modified exfoliated vermiculite are better than the thermal comfort properties of composite mortars produced using unmodified exfoliated vermiculite.</jats:p>

<jats:p xml:lang="en">Recycling end-of-life tires is a global problem that requires an urgent solution. Storing and preserving these tires is a challenge that delays facing potential problems instead of solving the problem. In this context, recycling waste tires without harming the environment and at low costs has been the focus of many researchers. For a few decades, the possibility of these tires to be granulated to the size of aggregate for concrete and then be replaced with natural aggregate has been a subject of research by scientists studying in this field. In this regard, this study aims to experimentally investigate the influence of waste rubber aggregate on some engineering properties of concrete, such as, ultrasonic pulse velocity-based quality assessment, abrasion resistance, and thermal conductivity characteristics as well as the mechanical performance, namely, compressive strength. Another significant side of the study was to establish a statistical relationship and correlation between the w/c ratio and substitution level of waste rubber aggregate and the experimental outputs. The experimental study indicated that the waste rubber aggregate decreased the compressive strength of the concretes whereas it improved the thermal conductivity characteristics and abrasion resistance of the concretes manufactured in this study. On the other hand, the statistical analysis revealed that the input parameters have meaningful effects on the engineering properties of the concretes, and there is a strong correlation between these properties.</jats:p>

<jats:p xml:lang="en">Factors such as the rapid depletion of natural resources and environmental pollution enable us to better understand the importance of the concept of sustainability today. With the introduction of the concept of sustainability into the construction sector, the design of buildings according to the environmentally friendly "Green Building" approach has come to the forefront, and various certification systems have been developed. Due to these certification systems, various building materials are required to be used in buildings. However, since there are many materials on the market, it is a problem as to which of these materials should we prefer according to the green building criteria. Although there are various approaches in this regard, the value engineering method is an ideal method because it takes into account both the criteria that the materials must meet as well as their costs. Value Engineering is the teamwork carried out to analyze the building properties, systems, equipment, and material selections, while considering the costs, in order to perform the necessary performance, quality, reliability, and basic functions. In this article, a method on how to choose a value-based, sustainable material was proposed, and as a case study, a product that can be used as an exterior cladding material of a building using LEED criteria, which is used for providing certification for sustainable green buildings, was selected. Initially, a value engineering team was formed. This team determined the qualities that the product should have based on LEED criteria and the eight different material alternatives that can meet these qualities. Subsequently, value analysis was conducted, and the highest value exterior coating material was determined.</jats:p>

<jats:p xml:lang="en">This study evaluated the suitability of iron tailings as fine aggregate replacement for engineering applications. This is necessary to find economic usage for the enormous quantity of wastes from Itakpe mines. The physical properties in terms of specific gravity, bulk density, moisture content, particle size and fineness modulus as well as the mechanical properties in terms of compressive strength, compaction factor, flexural strength and relative density of the concrete made with iron tailings were determined. World Health Organization (WHO) standard methods for the examination of water and wastewater were used to analyse water used for the curing of the concrete cubes and beams to ascertain its toxicity. The result shows the workability of concrete made with 50% iron tailings to be within the standard limit. The compressive strength at 28day for 0% to 100% percentage replacement increases from 10.1N/mm2 to 15.3N/mm2, therefore replacement of sand with iron filling will improve the compressive strength of any concrete. The flexural strength analysis shows that the iron tailings concrete beam increases the flexural strength from 15N/mm2 to 16.9N/mm2 from 0 to 100% at 28day curing. There is also a linear relationship between the flexural strength and the density of the iron tailing concrete. The pH and Alkalinity tests of the water used to cure the iron tailing concrete is an indication that the alkalinity of the curing water was high (20.883 to 40.75) with a pH range of 12.1-12.4. This shows that the use of the iron tailing will not have negative effect on durability of the resulting concrete, the iron tailings is suitable for fine aggregates replacement up to 75% without altering the mechanical properties of such concrete negatively.</jats:p>

<jats:p xml:lang="en">Microbial growth on man-made constructions is a planetary problem. Contaminated surfaces can rapidly spread dangerous infectious illnesses, especially in public places. A few microbes can easily multiply into millions, especially under current circumstances. A hygienic surface has defined as a component which inhibits the increase of micro-populations. Meanwhile, the use of biocides is expanding, as is research into their antibacterial characteristics and components. There are now various antimicrobial substrates on the market. It is worthwhile to investigate the efficacy and precision of these products. In this paper, an experiment has been made on six different wall paints which are promoted as antimicrobial are inspected against bacteria. Wooden panels had been painted with six different antimicrobial wall paints. Four different microorganisms were sprayed on the surface using a sterile spraying mechanism. The bacteria used in the study were Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis. Each panel had been observed for ninety days and the results had been discussed.</jats:p>

<jats:p xml:lang="en">The construction industry continues to be one of the primary drivers of a country's economic progress. As of 2022, the Philippines’ construction sector had an annual growth rate of 9.2% and continues to increase due to the Build! Build! Build! (BBB) program. However, construction sector is globally known for regularly consuming more raw materials, resulting in natural resource scarcity and environmental implications. Construction activities also generated massive volume of construction wastes from construction, demolition and renovation. The need to impose construction and demolition waste (CDW) management strategies and policies in all stages of construction is crucial in the attainment of a more sustainable construction. The aim of this study is to explore the current CDW management practices and policies from existing literature. The findings of this research will present a multitude of potential strategies and solutions that the Philippines can adopt to create more sustainable construction while also assisting in the combating of environmental issues and concerns in the attainment of sustainable construction. The study will utilize a Systematic Literature Review (SLR) to identify relevant studies in CDW management to gain the best practices and current trends in CDW management. The findings of the study shows that at least 26 different strategies have been implemented in the construction industry. These can be grouped into 6 major groups which includes: information technology, policy, design, operations, knowledge and procurement based.</jats:p>

<jats:p xml:lang="en">The diminishing quantity of the natural resources has resulted in a search for alternative materials. Reuse of industrial by-products, such as steel slag, provides opportunities for sustainable highway construction practices due to the valuable space they occupy and the potential environmental impacts when they are stockpiled. In this paper, the mechanical suitability of steel slag as an unbound highway aggregate is investigated and its performance is compared with that of traditional graded aggregate base (GAB) materials. In order to compare the behavior, three steel slag samples with different aging properties and five aggregate samples from different quarries were employed. The results indicate that resilient moduli and permanent deformation characteristics of steel slag are comparable with those of traditional aggregates and can replace them when used as a base or subbase course.</jats:p>

<jats:p xml:lang="en">Siklofan tipi bileşikler, kimyasal özelliklerinden dolayı ilginç bir organik kimya sınıfı oluşturmaktadır. Tüm siklik bileşiklerin yapısında yüksek verimli sentez için makrosiklizasyon en kritik konudur. Özellikle küçük bir siklofan yapısı ile deneysel adımlar büyük bir siklofan yapısına göre daha zordur.&#x0D; Bu yazıda, akıllı ilaç özellikleri için gümüş siklofan bileşiklerini sentezlemek üzere üç farklı malzeme grubu uygulanmıştır. Birinci malzeme grubunda 5,6-dimetil-1H-benzo[d]imidazol (1) ve 2,6-bis(klorometil)piridin (2) reaksiyona girerek 5,6-dimetil-1-((6) oluşturdu. -((5,6-dimetil-1H-benzo[d]imidazol-1-il)metil)piridin-2-il)metil)-1H-benzo[d]imidazol bileşik (3). İkinci malzeme grubunda etil 2-bromoasetat (4), suda çözünür (5) olan simetrik bir karben bileşiği oluşturmak üzere siklofan bileşiğinin farklı nitrojen atomları ile reaksiyona sokulmuştur. Üçüncü malzeme grubunda gümüş(I) oksit (6) ve paladyum (II) klorür (7) ile reaksiyona girerek gümüş (I) ve paladyum (II) metal kompleksleri sentezlendi.&#x0D; Karben bileşikleri ile gümüş ve paladyum komplekslerinin (5, 6 ve 7) bakteri ve mantarlara karşı antimikrobiyal aktiviteleri daha detaylı olarak incelenmiştir. Gümüş (I) kompleksi (6), Gram-pozitif, Gram-negatif ve mantar gibi mikroorganizmalar ile karıştırıldığında antimikrobiyal madde gösterirken, bu özellik paladyum (II)-karben kompleksinde (7) gözlenmemiştir.</jats:p>