Local Materials Research Articles

Entropy and Thermodynamic Temperature in Nonequilibrium Classical Thermodynamics as Immediate Consequences of the Hahn–Banach Theorem: II Properties

In a companion article it was shown in a certain precise sense that, for any thermodynamical theory that respects the Kelvin–Planck second law, the Hahn–Banach theorem immediately ensures the existence of a pair of continuous functions of the local material state—a specific entropy (entropy per mass) and a thermodynamic temperature—that together satisfy the Clausius–Duhem inequality for every process. There was no requirement that the local states considered be states of equilibrium. This article addresses questions about properties of the entropy and thermodynamic temperature functions so obtained: To what extent do such temperature functions provide a faithful reflection of “hotness”? In precisely which Kelvin–Planck theories is such a temperature function essentially unique, and, among those theories, for which is the entropy function also essentially unique? What is a thermometer for a Kelvin–Planck theory, and, for the theory, what properties does the existence of a thermometer confer? In all of these questions, the Hahn–Banach Theorem again plays a crucial role.

Meningkatkan Kesadaran Budaya Dalam Pendekatan CRT (Culturally Responsive Teaching) Pada Pembelajaran Sejarah Di Kelas X 1 SMA Negeri 1 Medan Tahun Pelajaran 2023/2024

This research aims to increase cultural awareness in class X 1 students at SMA Negeri 1 Medan through a culturally responsive teaching approach to history learning material. This research uses Classroom Action Research (PTK) with several stages including: planning, action or implementation, observation and reflection. The subjects of this research were 23 class X 1 students at SMA Negeri 1 Medan using quantitative data analysis. The research results showed that cycle I provided an explanation of local history material to students. In applying local history material, students ask questions about the material so that it fosters students' curiosity. Cycle II provides exposure to local historical material as well as carrying out vlog assignments to visit historical buildings to increase cultural awareness. From the results obtained, 43.5% of students gave their cultural awareness a slight increase while 56.5% of students gave the answer that their cultural awareness increased slightly.

Thermal behavior of Sicilian clay-based geopolymers

AbstractGeopolymers have been recently proposed for restoration of built heritage to substitute traditional mortars. Local materials and industrial wastes from the Italian region Sicily showed their potential as low-cost aluminosilicate sources for the preparation of geopolymers. Here, a set of Sicilian clays was studied by Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC), and its mineralogical composition was evaluated by X-ray diffraction (XRD). The raw materials were used to prepare geopolymers by alkaline activation with or without the addition of silicate. The thermal degradation profile of the final materials was studied by TGA and compared with that of the precursors, and the energetics of dehydration were investigated by DSC. Two statistical analyses (made by Principal Component Analysis) were performed on the TG data of raw materials and geopolymers and on the TG data of geopolymers and their mineralogical composition, respectively. The last analysis in particular showed a correlation between the mineralogical composition of the materials and the samples' thermal properties. Additional studies of samples subject to accelerated aging by UV irradiation and exposure to acetic acid vapors highlighted the different effects of these two agents on the samples’ stability. Graphical abstract

A Comparative Model of Thermal Performances Between a Modern and Classic Habitat for A Hot and Humid Tropical Climate: Case of Guinea

The objective of this research is to carry out a comparative study between a classic habitat and a modern habitat in order to understand which of the two is more efficient for a humid tropical area. To do this, a digital modeling of the heat transfer phenomena in the different components of the habitat was highlighted for a habitat made of stabilized earth bricks, a roof made of transparent tiles, false ceilings made of rectangular panels containing phase change material, concrete floor and a classic habitat made from local materials is presented. To show the reliability of this study, we validated our habitat model integrating phase change material through an experimental study carried out by researchers B. ZIVKOVIC and I. FUJII. A study on the temperature distributions at the level of certain components of the habitat done, and the influence of the variation of certain parameters was highlighted to know the thermal behavior of the two habitats. Furthermore, a comparative study was performed between the interior and exterior temperatures of the south walls of habitats incorporating PCM and without PCM, which are the components most exposed to solar radiation whose maximum values are respectively 33°C and 34, 5°C and 33.15°C against 47°C. Keywords: Performances, thermal, bioclimatic, PCM, Tropical climate, Guinea.

Thermal Insulation of “akassa” Hot Preservation Baskets Using Cow Dung Coatings

The use of eco-materials for thermal insulation is becoming more and more recommended compared with synthetic materials. They have the advantage of being biodegradable and sometimes less expensive. To this end, the use of packaging with the function of hot preservatives but made from local and biodegradable materials is a very interesting alternative to synthetic enclosures. This work involved formulating eco-materials made from cow dung coatings and a mixture of cow dung coatings with a framework of fibres extracted from the stalks of oil palm leaves. In addition, to monitor the temperature rise in the various eco-materials manufactured and characterise them using the hot ribbon method to determine their effusivity and thermal conductivity. The pair of materials exposed to heating showed a gradual rise in temperature within the materials when the resistor was energised. A slightly faster rise was observed in the first fifty minutes. The results obtained indicate that the cow dung has a higher effusivity (E = 517.32 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>) than its composite (E = 501.20 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>). The thermal conductivity values obtained indicate that the cow dung has a higher thermal conductivity (λ'=0.19 W.m^(-1).K^(-1)) than that of the composite structure (λ=0.15 W.m^(-1).K^(-1)). From the above, the presence of the fibre frame has the effect of reducing thermal conductivity because it absorbs more energy. The materials produced therefore have proven insulating properties, which are improved when the framework is made from fibres extracted from the stalks of oil palm leaves. Using oil palm fibres in combination with cow dung as eco-materials for thermal insulation is an excellent alternative to synthetic insulation.

Impacts of interfacial bonding between concrete substrate and cast/sprayed HPFRCC on flexural behaviour

The performance of repair materials is greatly enhanced by the integrity of the rehabilitation system, which depends on the behaviour of the boundary or interface bond between the repair material and the concrete substrate. The effects of the implementation of repair materials (casting or spraying), the spraying direction and the roughness of the concrete substrate on the interfacial bond behaviour were experimentally investigated through four-point bending tests on prisms of size 300 × 76.2 × 40 mm. As a first step, 2 cm thick concrete substrates were fabricated with five different types of surface roughness. After 28 days of curing, the repair material (a high-performance (high-ductility) fibre-reinforced cementitious composite (HPFRCC)) was sprayed or poured into specific moulds. The HPFRCC was developed using local materials and had a tensile strain capacity of 3.7%. The spraying direction and surface roughness of the concrete substrate were found to impact the ultimate deflection rate significantly; upward spraying produced the lowest deflection rate and downward spraying the highest. Because beams are often repaired from the lower part and spraying is in the upwards direction, the casting method must be used because of the negative effect of gravity on the interfacial bonding between the concrete substrate and the repair material.

Localizing for learning: a designed teacher training program and its developed localized materials for mother tongue education

Producing local materials is a challenge to mother tongue education programs especially in linguistically diverse contexts. To address this, a five-day teacher training program on materials localization for K–3 teachers in a linguistically diverse area in the Philippines was designed and implemented. The program was based on frameworks about materials localization and development, needs analysis data, and curricular and materials guidelines from the Ministry of Education. The program, implemented through the collaboration of stakeholders, capacitated teachers in localizing the language and culture in a set of lessons from Ministry-produced textbooks. These were evaluated and shown to have met standards of high-quality, localized materials. Results suggest that the designed program is a feasible grass-roots platform for localizing materials. The presented program design and activities, as well as the good practices and lessons learned from the implementation, are instructive to program implementers in linguistically diverse contexts.

Framework development for the physical vulnerability assessment index of hand-dug Wells in Are-Ekiti, Southwestern Nigeria.

The article presents a comprehensive framework for assessing the physical vulnerability of hand-dug wells within the Are Community, Southwestern Nigeria. The study spans from March to April 2023 and meticulously examines 90 wells, focusing on critical parameters such as well collar, well cover, and well lining information. The analysis reveals significant variations in well collar construction materials and dimensions, emphasizing the community's adaptive strategies. The Well Collar Height Index (WCi), Well Cover Index (WCOi), Well Lining Index (WLi), and the derived Vulnerability Index categorize wells into vulnerability classes, offering a nuanced understanding of susceptibility levels. Notably, the study identifies wells with Very High vulnerability that demand urgent attention, as well as wells with effective protective measures categorized as Very Low vulnerability. The article emphasizes the need for a nuanced understanding of local practices and materials, highlighting the variability in well collar construction. It discusses the implications of well cover conditions and the critical role of well linings in assessing groundwater vulnerability. The Vulnerability Index combines these parameters, guiding targeted interventions based on risk severity. The study lays the groundwork for future interventions to enhance the safety and sustainability of water sources within the Are Community. It recommends immediate comprehensive measures for highly vulnerable wells, ongoing monitoring, community engagement, and knowledge sharing. The future scope includes incorporating geochemical analysis, targeted interventions, regular maintenance, community training, and exploring alternative water sources for sustainable improvements.

Comparison of a quasi Newton method using Broyden’s update formula and an adjoint method for determining local magnetic material properties of electrical steel sheets

Purpose Performing accurate numerical simulations of electrical drives, the precise knowledge of the local magnetic material properties is of utmost importance. Due to the various manufacturing steps, e.g. heat treatment or cutting techniques, the magnetic material properties can strongly vary locally, and the assumption of homogenized global material parameters is no longer feasible. This paper aims to present the general methodology and two different solution strategies for determining the local magnetic material properties using reference and simulation data. Design/methodology/approach The general methodology combines methods based on measurement, numerical simulation and solving an inverse problem. Therefore, a sensor-actuator system is used to characterize electrical steel sheets locally. Based on the measurement data and results from the finite element simulation, the inverse problem is solved with two different solution strategies. The first one is a quasi Newton method (QNM) using Broyden's update formula to approximate the Jacobian and the second is an adjoint method. For comparison of both methods regarding convergence and efficiency, an artificial example with a linear material model is considered. Findings The QNM and the adjoint method show similar convergence behavior for two different cutting-edge effects. Furthermore, considering a priori information improved the convergence rate. However, no impact on the stability and the remaining error is observed. Originality/value The presented methodology enables a fast and simple determination of the local magnetic material properties of electrical steel sheets without the need for a large number of samples or special preparation procedures.

Manufacturing Process for Ameliorant Plus Mycorrhizal Powder Using Local Raw Materials for Soil Improvement

The development of ameliorant powder enriched with indigenous arbuscular mycorrhizae for soil amendment has been limited. This study presents a formulation process for creating a high-quality ameliorant powder using local raw materials. The powder incorporates a culture of Glomus mosseae isolate MAA-01, which constitutes 25% of the mixture, combined equally with compost powder, cattle manure powder, and rice husk charcoal powder. This formulation results in a product containing 2500 spores per 20 g of powder, achieving a 95% colonization rate, a moisture content of 5.002 % db, and a shelf life of 12 months. Laboratory tests confirm that this ameliorant powder significantly enhances soil fertility, as well as plant growth and yield, particularly in suboptimal land conditions. The production method is straightforward, making it highly suitable for local farmers seeking to improve agricultural productivity.

Assessing of Manual Sorting in Municipal Solid Waste: A Study Case in São Paulo City

The dependence of political factors and the lack of integrated municipal waste (MSW) management in metropolitan regions of developing countries turn selective collection and circular economy great challenges to be implemented. This paper presents the characterization of the selective household MSW sent to a manual sorting plant located in the central area of the São Paulo City, aiming to assess the real rejects that are going to sanitary landfill after sorting process. Six sampling campaigns were carried out at the input and output of the sorting process during a year (2016 to 2017). The results show that the materials from the selective collection destined to the plant already arrive with 13.8 % of rejects. In addition, there are about 49.8 % of dry and recycled materials after the sorting process, half of them without commercial value, technical recycling solution available or non-identified. This study shown that, independent of the efficiency and social problems in the totally manual sorting process, which was higher than the local Materials Recovery Facilities, the lack of recycling industries and the presence of dry, but not recyclable materials, as composite packaging, non-identified plastics, Styrofoam and electronics difficult the profitability of this kind of plant.

Effective Utilization of Local Fiber Coating Materials for Enhanced Sensitivity in Temperature and Humidity Sensing Applications

Effective Utilization of Local Fiber Coating Materials for Enhanced Sensitivity in Temperature and Humidity Sensing Applications

Phasing effects on thermo-mechanical fatigue damage investigated via crystal plasticity modeling

Nickel (Ni)-based superalloys have high strength at elevated temperatures, making them ideal candidates for aerospace components exposed to thermo-mechanical loads. Thermo-mechanical fatigue’s (TMF) influence on material failure is highly dependent on the temperature-load phase profile as a consequence of path-dependent thermo-mechanical plasticity. In order to understand the direct influence phasing effects have on TMF performance, a microstructure-based fatigue model has been developed to connect damage mechanisms to crack initiation events. In this work, in-phase (IP) TMF, out-of-phase (OP) TMF, and iso-thermal (ISO) loading profiles are investigated with a temperature-dependent, dislocation density-based crystal plasticity model to pinpoint a relationship between microstructural damage and TMF phasing effects. A crystal plasticity modeling framework with capabilities to isolate phasing (IP, OP, and ISO) effects is presented to locate fatigue damage in a set of statistically equivalent microstructures (SEMs) with an energy-based damage indicative parameter. Local stress, accumulated damage, intragranular misorientiation, grain interactions, and slip alignment activity at the damaged regions are studied under the various temperature-load phase profiles to connect microstructural material damage to TMF performance. Based on the local microstructural material damage, it is postulated the material’s stiffness at maximum load influences OP TMF performance, whereas the hardening/plasticity at maximum load influences IP TMF. The results from the presented framework is consistent with experimental evidence that at high mechanical strain amplitudes IP TMF has a shorter life as a consequence of hardening/plasticity influencing path-dependent thermo-mechanical plasticity, whereas at low strain amplitudes OP TMF has a shorter life due to stiffness influencing path-dependent thermo-mechanical plasticity.

Continuous Fiber Path Optimization in Additive Manufacturing: A Gradient-based B-spline Finite Element Approach

Additive manufacturing of continuous fiber enables the control of local material distribution and mechanical characteristics. This localized control is realized through fiber path generation and optimization, which is one of the core problems in the additive manufacturing of continuous fiber. Current fiber path generation and optimization methods mostly try to infill topology-optimized parts or align the fiber with the maximum stress directions, which may lead to sub-optimality or time-consuming computations. This paper provides a different approach to optimize the fiber path directly by parameterizing it with B-splines and manipulating its control points. A finite element model with B-spline fiber parameterization is established, with an analytical fiber-in-element probability. This framework streamlines the computation of local and global stiffness and mass matrices, enabling effective and efficient prediction of loading responses, stiffness, and natural frequencies. The probability framework also allows efficient calculation of the gradients of the stiffness and mass matrices, leading to a gradient-based fiber path optimization. The effectiveness and accuracy of both the finite element and optimization methods are verified with simulation and experiment case studies. Results demonstrate enhancements in stiffness and strength with less fiber usage compared to a commonly adopted principal stress direction method.

Eco-friendly biosorbent based on local raw material: application to dye removal

Eco-friendly biosorbent based on local raw material: application to dye removal

Pengaruh Pengetahuan Hijau dan Religiusitas Terhadap Eco-Inovasi Produk Berbahan Baku Etnobotani Lokal

This study is driven by the significance of developing herbal medicine using local ethnobotanical ingredients, incorporating green knowledge and religiosity to influence the actions of individual production employees. It investigates the essential role of green knowledge and religiosity in the eco-innovation of herbal medicine from local ethnobotanical sources. Focusing on Solo Raya's herbal medicine agroindustry, the research aims to explore the interplay between green knowledge, religiosity, and product eco-innovation, particularly from the perspective of production employees. Employing a case study and explanatory approach, 100 randomly selected production employees participated, and data were analyzed using structural equation model-partial least squares (SEM-PLS). Results indicate that green knowledge and religiosity significantly contribute to promoting eco-innovation. Green knowledge facilitates the creation of environmentally friendly products with local ethnobotanical materials, while religiosity offers ethical support for sustainable innovation practices. The study underscores the pivotal role of production employees in balancing environmental sustainability and religious values, emphasizing the crucial link between these aspects for advancing eco-innovation in the herbal medicine industry. This research enriches our understanding of eco-innovation dynamics in the agro-industrial sector by embracing green values and religiosity.

On-the-fly multiscale analysis of composite materials with a Generalized Finite Element Method

A multiscale computational framework to capture stress concentrations and localized nonlinearity in composite structures is presented. An enriched approximation space, constructed using the generalized finite element method (GFEM), is used to incorporate nonlinear, heterogeneous material behavior into coarse-scale models on the fly. Enrichment functions are constructed using the GFEM with global–local enrichment functions (GFEMgl). The auxiliary local problems associated with the GFEMgl also define fine-scale constitutive behavior that is inherited by the coarse global problem. This allows a coarse homogenized global problem to learn about material heterogeneity and/or nonlinearity on the fly, considerably increasing the flexibility of the method. On top of the explicit definition of heterogeneity in local problems, the locally defined constitutive law can incorporate further levels of heterogeneity that are not explicitly modeled at the global scale. The proposed GFEMgl comes with the efficiency and scalability characteristic of the method and greatly increases the flexibility when applied to heterogeneous structures with localized material nonlinearity.

XRF analysis of village and urban basalt architecture in the Hippos Territorium during the Roman period

AbstractThis case study examines the use of X‐ray fluorescence (XRF) as an effective method for defining distinct chemical compositions of local basalt stone from different sources in the Roman period, even when their quarries have not been identified. It also deals with the archaeological question if public and monumental structures from a village and urban site shared the same stone sources and stonemason's workshops. Ninety‐six samples from the Hippos Territorium, mainly from the polis of Hippos and the village of Majduliyya, were analyzed. XRF was found to be an effective method for defining distinct chemical compositions of local basalt materials from different sources. The distinct composition of the basalt stones between the two sites provided valuable insights into socio‐economic relationships, shedding light on the nature of city–village dynamics in the region. Additionally, it aids in discerning whether diverse basalt sources were utilized in both private and public constructions, as well as installations within a single site. Methodological questions and the application of this method in the archaeological research of basalt‐based architecture are also addressed.

Africa's natural fibres used in polymer composites: A systematic review

AbstractEnvironmental concerns and the depletion of petroleum resources have spurred research into natural fibres as sustainable alternatives to synthetic fibres as the reinforcement phase in polymer composites. Given that the local availability of materials is a crucial component in the sustainability framework, there is a need to map out the fibres used to develop natural fibre composites across geographical regions to optimize local resource utilization. Through a systematic review of publications sourced from Scopus and Web of Science databases, this study examines the contributions made by Africa to develop green polymer composites. The bibliometric data from both databases were systematically merged, and bibliometric analysis was carried out to identify trends and relevant relationships and provide a more general insight into Africa's progress in the natural fibre polymer composite field. A meta‐analysis was then conducted to identify the natural fibres exclusively sourced from Africa that have been used to develop polymer composites. The study also discussed natural fibre classifications with respect to fibre type and form. Sisal, palm varieties (particularly date palm), alfa, jute and members of the Musaceae family (i.e., banana, plantain and enset) were found to be the most used African‐sourced fibres. This study is a step to creating a more extensive global natural fibre database that seeks to provide more precise knowledge, enhance research efficiency, and ensure the utilization of local materials in creating more sustainable composites.Highlights The use of local materials is a key component of sustainable development A natural fibre database can foster sustainability in the composite industry Egypt, Morocco, and Tunisia are leading Africa's composite research Research prioritizes composite material science over practical applications Sisal, date palm, alfa and jute are the most used natural fibres in Africa

Experimental study on thermal and humidity properties of modified rammed earth buildings in winter

Rammed earth materials have been used in traditional buildings for thousands of years. Currently, with the interest in environmentally friendly societies, rammed earth construction has regained attention owing to its characteristics of energy conservation, environmental protection, low cost, and local material extraction. In this study, cement, gravel, sand, and polypropylene fibers were used as the modifying materials of rammed earth. The thermal and humidity physical parameters are measured at different moisture contents after modification, and the isothermal hygroscopic curves are fitted. The experimental findings demonstrated positive correlations between the specific heat capacity and thermal conductivity and the moisture content. The temperature and humidity of a modified rammed earth test building were recorded for seven days during winter. The test findings revealed that, throughout the test, the moisture content in the middle of the wall was consistently higher than that in the inner surface. When the outdoor temperature fluctuation was 14.95 °C, the inner surface temperature and indoor temperature fluctuation were 2.73 °C and 3.08 °C, respectively. Moreover, the inner surface temperature of the wall became maximum 7–8 h after the maximum outer surface temperature is reached, on average. The above data show that a modified rammed earth wall has exceptional heat and moisture storage capacities as well as heat and moisture buffering characteristics, which can reduce fluctuations in indoor temperature and humidity and create a more comfortable indoor living environment.