Predicting Slump Values of Concrete Made by Pozzolans and Manufactured Sand using ANN

Large amounts of natural fine aggregate (NFA) and cement are used in building, which has major environmental consequences. This view of industrial waste can be used in part as an alternative to cement and part of the sand produced by the crusher as fine aggregate, similar to slag sand (GGBFS), fly ash, metacaolin, and silica fume. Many times, there are issues with the fresh characteristics of concrete when using alternative materials. The ANN tool is used in this paper to develop a Matlab software model that collapses concrete made with pozzolanic material and partially replaces natural fine aggregate (NFA) with manufactured sand (MS). Predict. The slump test was carried out in reference with I.S11991959, and the findings were used to create the artificial neural network (ANN) model. To mimic the formation, a total of 131 outcome values are employed, with 20% being used for model testing and 80% being used for model training. 25 enter the material properties to determine the concrete slump achieved by partially substituting pozzolan for cement and artificial sand (MS) for natural fine aggregate (NFA). According to studies, the workability of concrete is critically harmed as the amount of artificial sand replacing natural sand grows. The ANN model's results are extremely accurate, and they can forecast the slump of concrete prepared by partly substituting natural fine aggregate (NFA) and artificial sand (MS) with pozzolan.

Seashells and Oyster Shells: Biobased Fine Aggregates in Concrete Mixtures

The construction industry is the largest global consumer of materials, among which sand plays a fundamental role; now the second most used natural resource behind water, sand is the primary component in concrete. However, natural sand production is a slow process and sand is now consumed at a faster pace than it’s replenished. One way to reduce consumption of sand is to use alternative materials in the concrete industry. This paper reports the exploratory study on the suitability of aquaculture byproducts as fine aggregates in concrete mixtures. Seashell grit, seashell flour and oyster flour were used as sand replacements in concrete mixtures (10%, 30% and 50% substitution rates). All the mixtures were characterized in fresh and hardened states (workability, air content, compressive strength and water absorption). Based on compressive strength, measured at 7 and 28 days, seashell grit provided the most promising results: the compressive strength was found to be larger than for conventional concrete. Moreover, the compressive strength of the cubes was larger, when larger percentages of seashell grit were used, with the highest value obtained for 50% substitution. However, for oyster flour and seashell flour, only 10% sand substitution provided results comparable with the control mixture. For the three aggregates, workability of concrete decreases with fineness modulus decrease. For mixtures in which shell and oyster flour were used with 30% and 50% substitution percentages, it was necessary to increase the quantity of mixing water to allow a minimal workability. In conclusion, considering the promising results of the seashell grit, it is suggested to study further the characteristic of the material, also considering its environmental and physical properties, including acoustic and thermal performances. Higher substitution percentages should also be investigated. This research adds to the relevant literature in matter of biobased concrete, aiming at finding new biobased sustainable alternatives in the concrete industry.

New Frontiers in Cementitious and Lime-Based Materials and Composites

Cement and lime currently are the most common binders in building materials. However, alternative materials and methods are needed to overcome the functional limitations and environmental footprint of conventional products. This Special Issue is entirely dedicated to “New frontiers in cementitious and lime-based materials and composites” and gathers selected reviews and experimental articles that showcase the most recent trends in this multidisciplinary field. Authoritative contributions from all around the world provide important insights into all areas of research related to cementitious and lime-based materials and composites, spanning from structural engineering to geotechnics, including materials science and processing technology. This topical cross-disciplinary collection is intended to foster innovation and help researchers and developers to identify new solutions for a more sustainable and functional built environment.

Penyuluhan dan Pelatihan Pembuatan Hand Sanitizer di Desa Tambakbaya Kota Garut Sebagai Langkah Pencegahan Covid 19

ABSTRAKPandemi Covid-19 yang terjadi saat ini beberapa waktu yang lalu menyebabkan kelangkaan hand sanitizer dipasaran, hal ini membuat resah sebagian masyarakat. Pembuatan hand sanitizer yang dibuat dengan komposisi yang kurang tepat maka efektivitas hand sanitizer dalam membunuh bakteri dan virus tentunya akan berkurang. Pemanfaatan bahan alam sebagai bahan alternatif dalam pembuatan hand sanitizer. Diketahui beberapa tanaman yang memiliki kemampuan daya hambat terhadap bakteri yang bisa digunakan sebagai zat aktif maupun zat tambahan di dalam produksi hand sanitizer salah satunya adalah lidah buaya. Tujuan dari kegiatan pengabdian ini adalah menghasilkan suatu produk kesehatan yang dapat dimanfaatkan baik untuk diri sendiri, keluarga dan masyarakat sekitar dalam rangka untuk mencegah penyebaran virus Covid-19. Metode yang digunakan dengan memberi penjelasan kegunaan dan keunggulan sediaan hand sanitizer yang terbuat dari bahan alami yaitu lidah buaya (Aloe vera) melalui video dan pamflet. Hasil dari kegiatan pengabdian kepada masyarakat ini dinilai dapat memberikan dampak positif kepada masyarakat Desa tambakbaya, Kecamatan Cisurupan, Kabupaten Garut dilihat dari antusiasme masyarakat Desa dalam menerima pamflet dan video sebagai sumber informasi yang sangat bermanfaat bagi mereka dalam membuat hand sanitizer berbahan dasar alami (Aloe vera) sehingga bisa dirasakan manfaatnya. Kerjasama antara kepala Desa dan aparatur Desa harus terus ditingkatkan agar dampak positif dapat menjadi dampak berkelanjutan. Kata Kunci: Hand sanitizer, antiseptik alami, aloe vera, pencegahan virus corona ABSTRACTThe Covid-19 pandemic that occurred some time ago caused the scarcity of hand sanitizers in the market, this made some people nervous. Making hand sanitizers that are made with inappropriate compositions will reduce the effectiveness of hand sanitizers in killing bacteria and viruses. Utilization of natural materials as alternative materials in making hand sanitizers. It is known that several plants can inhibit bacteria which can be used as active substances or additives in the production of hand sanitizers, one of which is aloe vera. The purpose of this service activity is to produce a health product that can be used for both yourself, your family, and the surrounding community to prevent the spread of the Covid-19 virus. The method used is to explain the uses and advantages of hand sanitizer preparations made from natural ingredients, namely aloe vera (Aloe vera) through videos and pamphlets. The results of this community service activity are considered to have a positive impact on the people of Tambakbaya Village, Cisurupan District, Garut Regency, seen from the enthusiasm of the Village community in receiving pamphlets and videos as a source of information that is very useful for them in making hand sanitizers made from natural ingredients (Aloe vera) so that the benefits can be felt. Cooperation between the village head and village officials must be continuously improved so that positive impacts can become sustainable impacts. Keywords: Hand sanitizer, natural antiseptic, aloe vera, coronavirus prevention

Hydration–Strength–Workability–Durability of Binary, Ternary, and Quaternary Composite Pastes

At present, reducing carbon emissions is an urgent problem that needs to be solved in the cement industry. This study used three mineral admixtures materials: limestone powder (0–10%), metakaolin (0–15%), and fly ash (0–30%). Binary, ternary, and quaternary pastes were prepared, and the specimens’ workability, compressive strength, ultrasonic pulse speed, surface resistivity, and the heat of hydration were studied; X-ray diffraction and attenuated total reflection Fourier transform infrared tests were conducted. In addition, the influence of supplementary cementitious materials on the compressive strength and durability of the blended paste and the sustainable development of the quaternary-blended paste was analyzed. The experimental results are summarized as follows: (1) metakaolin can reduce the workability of cement paste; (2) the addition of alternative materials can promote cement hydration and help improve long-term compressive strength; (3) surface resistivity tests show that adding alternative materials can increase the value of surface resistivity; (4) the quaternary-blended paste can greatly reduce the accumulated heat of hydration; (5) increasing the amount of supplementary cementitious materials can effectively reduce carbon emissions compared with pure cement paste. In summary, the quaternary-blended paste has great advantages in terms of durability and sustainability and has good development prospects.

Methodology for composite materials shrinkage definition for use in shipbuilding and marine technology

Deformations of steel material in shipbuilding and marine technology applications as a result of mechanical or temperature influences are a well-known problem. However, in the modern shipbuilding industry, the application of alternative materials, especially composite materials, in the structure and for the equipment of the ship is increasingly represented. Consequently, there is a need to determine the deformation and change of characteristics of such composite materials as a result of various mechanical, and especially temperature influences that cause the so-called shrinkage. The basic composite production process involves connecting the matrix with a catalyst and accelerators that create temperature, then the material shrinks by cooling when it can change its dimensions and characteristics. Also, in order to achieve the best possible mechanical properties, composite materials are specially heated and then cooled according to strictly defined processes and curves. The ability to predict the characteristics and parameters of such deformations is important in the context of the application of composite materials. To define such deformations, different methods are used within individual numerical solvers, whose results can differ significantly from each other. Therefore, the authors in this paper present an established methodology for predicting mechanical and temperature deformations, and modelling of composite materials, based on the analysis of analytical methods and numerical solvers with the aim of defining the most accurate numerical solver. By applying the presented methodology, it is expected to raise the level of accuracy and quality of composite materials production as well as to raise the quality of design solutions and efficiency of production procedures during shipbuilding in particular, but also within different marine technology applications and during the product’s life cycle.

Comparative Analysis of the Cooling Efficiency in Tropical Climate of Three Alternative Materials for Evaporative Cooling Pads

A comparison between commercial cellulose evaporative cooling pad and pads manufactured with three alternative materials was made for environmental conditions typical of tropical countries. Wind tunnel tests were carried out to compute the convective heat and mass transfer coefficients and to measure the pressure drop across each pad, obtaining expressions that can be used as reference for future simulations. Using a mathematical model, a detailed analysis of the efficiency, Temperature–Humidity Index, temperature drop and relative humidity through the pads was performed in terms of different operative and constructive conditions, such as air velocities, dry-bulb temperatures, relative humidity and pad thickness. Significant differences between the pressure drop across the pads were found, which increases with the inlet air velocity and water flow. A weak relation between the analysed variables and the inlet air velocity was found, while a high correlation between the analysed variables, pad thickness and the external environmental conditions was established. Cooling efficiencies above 40% and a Temperature–Humidity Index below the mild zone of thermal stress were obtained for the alternative panels. Although the cellulose cooling pad showed the best behaviour in all aspects, the alternative pads can be used as substituted in specific applications to reduce the Temperature–Humidity Index inside agricultural facilities.

Cost-Effective 1T-MoS2 Grown on Graphite Cathode Materials for High-Temperature Rechargeable Aluminum Ion Batteries and Hydrogen Evolution in Water Splitting

The high dependence on and high cost of lithium has led to a search for alternative materials. Aluminum ion batteries (AIBs) have gained interest due to their abundance, low cost, and high capacity. However, the use of the expensive 1-ethyl-3-methylimidazolium chloride (EMIC) electrolyte in AIBs curtails its wide application. Recently, high-temperature batteries have also gained much attention owing to their high demand by industries. Herein, we introduce cost-effective 1T molybdenum sulfide grown on SP-1 graphite powder (1T-MoS2/SP-1) as a cathode material for high-temperature AIBs using the AlCl3-urea eutectic electrolyte (1T-MoS2/SP-1–urea system). The AIB using the 1T-MoS2/SP-1–urea system exhibited a capacity as high as 200 mAh/g with high efficiency of 99% over 100 cycles at 60 °C when cycled at the rate of 100 mA/g. However, the AIB displayed a capacity of 105 mAh/g when cycled at room temperature. The enhanced performance of the 1T-MoS2/SP-1–urea system is attributed to reduced viscosity of the AlCl3-urea eutectic electrolyte at higher temperatures with high compatibility of 1T-MoS2 with SP-1. Moreover, the electrocatalytic lithiation of 1T-MoS2 and its effect on the hydrogen evolution reaction were also investigated. We believe that our work can act as a beacon for finding alternative, cost-effective, and high-temperature batteries.