Material Production Research Articles

Hybrid Waste-to-Energy Solutions within a Circular Economy Framework Directed towards Sustainable Urban Waste Management in Ghana

Cities in developing countries continue to struggle with mounting waste management challenges. Within a circular economy framework, energy recovery is mostly nonexistent. Against that background, this study aimed to design and assess the viability of a hybrid waste-to-energy facility for the Greater Accra Metropolitan Area (GAMA) in Ghana by 2030. The proposed plant integrates solar PV, anaerobic digestion and pyrolysis to treat unsegregated municipal solid waste. Three cases were developed for different product combinations. Material flow analysis was performed with STAN software 2.7.101. The results indicate that 1.6 million tons of MSW will be generated, to be potentially converted to 271 GWh of electricity, 6400 tons of hydrogen or 4400 tons of bio-compressed natural gas per year, along with additional products: compost, refuse-derived fuel and bio-oil. The economic indicators show that all cases are potentially viable in terms of the net present value (EUR 397 to 1030 million), internal rate of return (14–22%) and levelized cost of energy (0.11–0.18 EUR/kWh). As such, this study proves that waste to energy is a viable waste management solution for large metropolitan areas, with the potential to supply energy, alternative fuels and material products within a circular economy, though it requires the buy-in of policy makers.

A New Approach for On-Chip Production of Biological Microgels Using Photochemical Cross-Linking.

Photochemical cross-linking is a key step for manufacturing microgels in numerous applications, including drug delivery, tissue engineering, material production, and wound healing. Existing photochemical cross-linking techniques in microfluidic devices rely on UV curing, which can cause cell and DNA damage. We address this challenge by developing a microfluidic workflow for producing microgels using visible light-driven photochemical cross-linking of aqueous droplets dispersed in a continuous oil phase. We report a proof-of-concept to construct microgels from the protein Bovine Serum Albumin (BSA) with [Ru(bpy)3]2+ mediated cross-linking. By controlling the capillary number of the continuous and dispersed phases, the volumetric flow rate, and the photochemical reaction time within the microfluidic tubing, we demonstrate the construction of protein microgels with controllable and uniform dimensions. Our technique can, in principle, be applied to a wide range of different proteins with biological and responsive properties. This work therefore bridges the gap between hydrogel manufacturing using visible light and microfluidic microgel templating, facilitating numerous biomedical applications.

MaterialsMap: A CALPHAD-based tool to design composition pathways through feasibility map for desired dissimilar materials, demonstrated with resistance spot welding joining of Ag-Al-Cu

Assembly of dissimilar metals can be achieved by different methods, for example, casting, welding, and additive manufacturing (AM). However, undesired phases formed in liquid-phase assembling processes due to solute segregation during solidification diminish mechanical and other properties of the processed parts. In the present work, an open-source software named MaterialsMap, has been developed based on the CALculation of Phase Diagrams (CALPHAD) approach. The primary objective of MaterialsMap is to facilitate the design of an optimal composition pathway for assembling dissimilar alloys with liquid-phases based on the formation of desired and undesired phases along the pathway. In MaterialsMap, equilibrium thermodynamic calculations are used to predict equilibrium phases formed at slow cooling rate, while Scheil-Gulliver simulations are employed to predict non-equilibrium phases formed during rapid cooling. By combining these two simulations, MaterialsMap offers a thorough guide for understanding phase formation in various manufacturing processes, assisting users in making informed decisions during material selection and production. As a demonstration of this approach, a compositional pathway was designed from pure Al to pure Cu through Ag using MaterialsMap. The design was experimentally verified using resistance spot welding (RSW).

Study on mechanical properties of E-glass mat reinforced basic magnesium sulfate cement thin-slab

To achieve sustainable development and reduce the carbon footprint in building material production, the E-glass fiber mat was impregnated with basic magnesium sulfate cement (BMSC) by lamination impregnation. This process reduces environmental pollution from cement preparation, increases fiber volume content, and enhances the mechanical properties of cementitious composite materials. The study examined axial tensile, four-point bending resistance, drop weight impact resistance and pendulum impact resistance of BMSC thin-slab reinforced with dispersed short glass fiber (SGF), short glass fiber mat (SGFM) and continuous glass fiber mat (CGFM) of varying gram weights. The results show that the mechanical properties of BMSC thin-slab reinforced with fiber mat are much higher than those of SGF reinforced thin-slab. The tensile strength of BMSC thin-slab reinforced with CGFM is higher than that of BMSC thin-slab reinforced with SGFM at the same gram weight, and the tensile strength increases as the weight of CGFM increases. Specifically, the axial tensile strength of BMSC thin-slab reinforced with 450 g of CGFM is nearly 8 times higher than that of SGF reinforced BMSC thin-slab. BMSC thin-slab reinforced with 450 g of CGFM has the maximum proportional limit load and bending strength. The impact strength and toughness indexes of BMSC thin-slab reinforced with CGFM are the highest, followed by SGFM reinforced BMSC thin-slab. The addition of 300 g CGFM significantly enhanced flexural toughness during the early stage of thin-slab cracking, while 450 g CGFM showed significant improvement in flexural toughness during the middle and late stages of cracking. When comparing thin-slabs with the same glass fiber volume ratio, those reinforced with 450 g CGFM exhibited the best impact resistance. SEM results indicated superior adhesion between 450 g CGFM and the cement matrix, as well as between adjacent CGFM layers, with fiber breakage being the main cause of specimen failure.

Calcium Orthophosphate (CaPO4) Containing Composites for Biomedical Applications: Formulations, Properties, and Applications

The goal of this review is to present a wide range of hybrid formulations and composites containing calcium orthophosphates (abbreviated as CaPO4) that are suitable for use in biomedical applications and currently on the market. The bioactive, biocompatible, and osteoconductive properties of various CaPO4-based formulations make them valuable in the rapidly developing field of biomedical research, both in vitro and in vivo. Due to the brittleness of CaPO4, it is essential to combine the desired osteologic properties of ceramic CaPO4 with those of other compounds to create novel, multifunctional bone graft biomaterials. Consequently, this analysis offers a thorough overview of the hybrid formulations and CaPO4-based composites that are currently known. To do this, a comprehensive search of the literature on the subject was carried out in all significant databases to extract pertinent papers. There have been many formulations found with different material compositions, production methods, structural and bioactive features, and in vitro and in vivo properties. When these formulations contain additional biofunctional ingredients, such as drugs, proteins, enzymes, or antibacterial agents, they offer improved biomedical applications. Moreover, a lot of these formulations allow cell loading and promote the development of smart formulations based on CaPO4. This evaluation also discusses basic problems and scientific difficulties that call for more investigation and advancements. It also indicates perspectives for the future.

Environmental and Economic Analysis of Reusable and Single‐Use Food Packaging Formats in University Campus Food Services

ABSTRACTThe purpose of this study is to assess the environmental and economic impacts of the various food packaging systems offered in university food services in Canada. Toronto Metropolitan University's food service was chosen as a test case. Three systems exist in this setting: single‐use polypropylene (PP) containers, reusable PP clamshells and compostable bagasse clamshells. The goal is to understand which system has the most favourable impact regarding the Tool for the Reduction and Assessment of Chemical and other environmental Impacts' (TRACI 2.1) 10 impact categories and which system is the most financially viable through a cost analysis. The scope includes a cradle‐to‐grave life cycle assessment (LCA) consisting of raw material extraction and production, transportation, usage and end‐of‐life disposal. This study investigates the environmental impact of each packaging system for 10 000 meals consumed by students. This research follows two ISO standards, 14044:2006, and 14040:2006. These standards involve defining the goal and scope, completing a life cycle inventory (LCI) analysis, completing a life cycle impact assessment (LCIA) and interpreting the life cycle. LCI information is extracted using SimaPro v9.0. The study results reveal that the reusable PP clamshell has the least environmental impact when compared to the two other single‐use packaging alternatives for nine of the 10 environmental impact categories. The single‐use PP container has the most significant environmental impact due to its harmful material extraction, production processes and end‐of‐life emissions. The sensitivity analysis determined that if reused a minimum number of 37 times, the reusable clamshell (RU) remains favourable to the single‐use formats in nine of the 10 impact categories. Furthermore, the cost analysis reveals that the reusable packaging format is the most financially favourable when reused 16 times or more. This research concludes that single‐use food packaging options have a more significant environmental impact than reusable PP clamshells. Based on the research findings, purchasing a less harmful detergent, sourcing the packaging locally and reducing the loss rate of reusable PP clamshells could produce an even more favourable environmental impact for the reusable food packaging system.

Reference Material Production and Milk Protein Concentration as Elements to Improve Bluetongue Serological Diagnosis in Bulk Tank Milk.

The serological surveillance of bluetongue in bulk tank milk is an efficient and cost-effective method for the early detection of bluetongue virus incursions in unvaccinated free areas of the disease. In addition, the availability of standardized and reliable reagents and refined diagnostic procedures with high sensitivity and specificity are essential for surveillance purposes. However, no available reference materials for bluetongue virus serological surveillance in bulk tank milk exist. This study shows the production and characterization of reference material for the implementation of a commercially available bluetongue milk ELISA test in official laboratories, as well as the evaluation of a procedure to increase the sensitivity in samples with low levels of antibodies. This procedure, based on milk protein concentration, allowed us to notably increase the ELISA test's analytical sensitivity, which is useful for milk samples from farms with low within-herd prevalence or pools of bulk tank milk samples. The standardized milk reference material produced here, together with the evaluated procedure to improve analytical sensitivity, could be applied as tools to ensure an accurate diagnosis by official laboratories in bluetongue unvaccinated free areas.

Engineering Economy Studies on the Development and Production of Yoghurt using Indigenous Starter Culture

In this paper, the economic viability of the production of yoghurt using indigenous starter culture is determined. Based on an output of 180 x 103 litres/year, the yield of the product, the quantities and costs of raw materials, centrifuge and incubator, were estimated at 100% capacity utilization (CU). The costs of land acquisition and factory building were obtained from contractors. The labour cost was also estimated for 60 staff members. The selling price of ₦120/litre of a similar product was adopted. Annual worth (AW), and present worth (PW) were calculated and used to establish the profitability of the products. The results showed that the proposed plant would produce 180 x 103 thousand litres of the yoghurt at full CU. The PW and AW showed that the product was economically viable with PW and AW greater than zero at 100% CU. At 100%, all the profitability indices for the product were positive. In conclusion, the production of yoghurt using indigenous starter culture is technologically and economically viable.

Research on the Current Situation and Calculation Method of Carbon Emissions Assessment for Building Curtain Walls

Curtain wall systems stand out as a pivotal domain within the construction sector’s endeavors towards energy efficiency and carbon mitigation. To refine the evaluation framework for carbon emissions within this industry, this paper explores the calculation and assessment method for building curtain walls. The article first reviews the current research status regarding carbon emissions from materials and the impact of curtain walls on buildings in the operational stage. Based on lifecycle theory, the carbon emissions from building curtain walls are divided into six stages: material acquisition, processing and production, installation and construction, transportation, use and maintenance, and dismantling. On this basis, this paper proposes a method for calculating carbon emissions from building curtain walls. Following that, a case study is conducted using a specific glass curtain wall project for illustrative analysis. The results indicate that the carbon emissions from the material acquisition stage constitute approximately 90% of the total, serving as the primary source of carbon emissions for glass curtain walls. Furthermore, the scientific application of photovoltaics can significantly reduce the carbon emission levels of building curtain walls. Finally, an analysis was conducted on the current issues existing in the evaluation of carbon emissions.

Spatio-Temporal Analysis of Resources and Waste Quantities from Buildings (as Urban Mining Potential) Generated by the European Metropolis of Lille: A Methodology Coupling Data from Construction and Demolition Permits with Geographic Information Systems

The aim of this article was to conduct a spatial and territorial analysis of the urban mining potential of the European Metropolis of Lille (MEL), which had 1,174,273 inhabitants in 2018. This involved quantifying construction and demolition waste (CDW) deposits and analyzing their spatial distribution. The chosen quantification approach utilized building and demolition permits as input data, along with waste diagnostics for Construction and Building Materials Products (CBMPs) obtained from stakeholders in the building sector. Waste quantities were estimated using the production rate calculation method (GRC). Specifically, the calculation based on surface area combined with GIS geographic information systems. CDW quantities were categorized by demolition rehabilitation and construction; by type (hazardous non-hazardous inert); and by urban fabric. For the MEL area, the findings revealed that building sites covered the largest surface area, with over 8 million m² being constructed between 2013 and 2022. The construction activity, including renovation, is expected to constitute approximately 20% of the MEL’s building stock from 2013 to 2022. During the same period, 5.51% of the MEL’s building stock was demolished. This corresponds to nearly 6 million tons of CDW being generated during this period, averaging 661318 tons per year. Demolition sites contributed 73% of the total CDW production, compared to 22% for new construction and 4% for renovation sites. Inert waste continued to dominate the composition of waste, accounting for 90% of the total with 9% for non-hazardous waste and 1% for hazardous waste. Semi-detached and grouped houses business fabrics and townhouses or collective fabrics were identified as the primary type of waste-producing urban fabrics. Furthermore, our GIS-based methodology enabled the analysis of CDW quantity distribution by municipality, providing essential data for understanding the urban mining potential and the disparity between construction material requirements for new buildings and resources derived from building demolition. This approach facilitates the assessment of (1) a geographical area’s reliance on construction materials, and (2) the significance of reusing and recycling products equipment materials and waste (PEMW) in new construction to achieve circular economy objectives and to comply with the Extended Producer Responsibility (EPR) channel initiated in France in 2023. Over the period from 2013 to 2022, annual construction material requirements remained significantly higher than resources from building demolition and rehabilitation, ranging between 29% and 35%. Additionally, the analysis indicated a potential 41% rate of substitution of new construction materials with secondary primary materials in the MEL, varying by municipality and typology, with higher rates in rural communities and lower rates in urban communities.

What investments in material production are needed to achieve net-zero construction in the UK by 2050?

Meeting the goal of reaching zero emissions by 2050 requires profound changes in the production of bulk materials, cement and concrete. For construction sector, this transition is also dependent on the evolution of demand, stemming from changes in the population structure and practice in structural design. Many timelines have been produced suggesting pathways to zero emissions, but none have looked at the required investment level, or the feasibility of transition looking at the level of single plants being shut, transformed or built within a single country. In this paper, we have looked at transition pathways in the United Kingdom as a function of the available funding and the possible emergence of transformative technologies. We find that trade is a necessary component of the transition, allowing for continued construction while the production apparatus is upgraded. Our results further suggest that the current level of investment is consistent with today’s carbon price but falls short of what is necessary to achieve net zero by 2050. Finally we find that pathways assuming that CCS will be available at scale are particularly susceptible to overshoot their emissions target if the technological deployment fails to materialise. This is because they combine heavy investments, immature technology and concentrated risk.

Life cycle assessment of pavement construction: A case study

Abstract Road construction is often associated with carbon emissions from direct and indirect sources, primarily due to construction and maintenance activities. Currently, there is a lack of comprehensive Life Cycle Assessment (LCA) benchmarks to evaluate flexible composite pavement, fully flexible pavement and pavement rehabilitation options under various ground conditions. The objective of this study is to investigate the environmental impact associated with different pavement designs over a 60-year analysis period, comprising a 40-year basic design period with maintenance extended up to 60 years. This research paper encompasses a literature review on pavement LCA and conducts and LCA on various pavement design and construction options, following the ISO 14040 framework and PAS 2080 methodology. The LCA in this study specifically focuses on material production, transportation, construction, maintenance, and end-of-life phases. Using global warming potential as an environmental indicator, the study calculates and compares a range of potential impacts for each component. In terms of carbon emissions, the rehabilitation option was found to be most favourable when compared to other full-depth reconstruction options, while the flexible composite pavement option exhibited the highest carbon emission value compared to other pavement build-ups assessed. Additionally, a sensitivity analysis was conducted to identify ‘hotspots’ in the study, which increase the confidence level of the results.

Application of Class-Based Characteristic Economic Teaching Materials for High School Students in Singkawang City

This research uses a Design Based Research (DBR) approach to develop and test Economics teaching materials with the dimension of strengthening character education for high school students in Singkawang City. The aim of this research is to produce teaching materials that not only increase understanding of economic material, but also help students internalize character values that are relevant to social, cultural and economic change. The problem faced is how to create effective and relevant teaching materials in the context of ongoing changes. The method used includes field trials with an experimental design, where the teacher applies the developed teaching materials in the learning process. The test subjects were high school students in Singkawang City, with data collected through observation and tests. Data analysis uses qualitative analysis for the field test implementation process and the Wilcoxon Test to determine the effectiveness of teaching material products. Specific results showed significant improvements in student learning outcomes, with an average pre-test score of 43.63 increasing to 55.35 in the post-test. In general, the results of this research show that teaching materials with character are effective in improving economic learning outcomes and shaping the character of students. In conclusion, the application of economic teaching materials based on strengthening character education can prepare students to become the golden generation of 2045 who excel in skills, competence and character.

Metal-Based Implants: Review of Materials and Designs

The purpose of implants is to replace, restore, maintain or improve the functionality of various tissues and organs of the human body. Their use in modern medicine has significantly improved treatment methods and increased the quality and life expectancy of patients. The most preferable from the point of view of the possibility of imparting the required mechanical properties, the relatively low cost of the material and low production costs are metal implants. Metals and their alloys in the production of implants are superior to ceramic and polymer materials in a range of properties such as tensile strength, endurance limit, wear resistance, hardness, elasticity, viscosity, shape memory effect. The paper provides an overview of the designs of modern implants for various purposes and the metal materials used for their production. An analysis of literature sources has shown that modern implants made of metal materials represent a wide range and have significant differences in shape and size. Some of them are characterized by a small cross-section and rigidity, while possessing elastic properties. Other products are load-bearing, in some cases massive, structures. According to the proposed classification, according to their purpose, metal implants are divided into: dental, cranial, maxillofacial, vertebral, traumatological, cardiovascular and joint endoprostheses. An analysis of the advantages and disadvantages of the main metal materials used in the production of implants (corrosion-resistant steel, titanium and titanium alloys, cobalt-chromium alloys and nitinol) has been performed. It has been established that all currently used biocompatible metal materials are not completely inert towards the body. Each material in any case causes some reaction in the surrounding tissues. The greatest biocompatibility and corrosion resistance in the body is provided by technical titanium, which, however, has low strength characteristics.

Recycling of waste crushed stone powder for alkali-activated material production

Recycling of waste crushed stone powder for alkali-activated material production

Investigating the grinding characteristics of vanadium-titanium iron ore tailings for sustainable utilization in cementitious material preparation

The study of the cementitious material activity of industrial solid wastes is a key issue in the comprehensive utilization of its green building materials. In this study, mechanical activation was used to prepare cementitious materials from vanadium-titanium iron ore tailings (VTIOT) as the main raw materials, and the effects of grinding time, the key parameter, on the grinding characteristics of VTIOT, the mechanical properties of the VTIOT cementitious material, and the hydration mechanism were investigated by means of surface area analysis, particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), alkali leaching, mechanical testing, hydration heat analysis, and thermogravimetric analysis (TGA). The results show that: the grinding time and specific surface area of VTIOT exhibit a linear correlation. Prolonging the grinding time, the fractal dimension of the particles gradually increases. The activity of Si4+ and Al3+ elements increases rapidly, reaching a Si4+ and Al3+ content of 96 mg·L−1 at 90 min of grinding. With a VTIOT mixing amount of 30 %, a mortar paste ratio of 1:3, and a water cement ratio of 0.5, the 50 min ground VTIOT mortar demonstrates 7 d and 28 d compressive strengths of 29 MPa and 38.7 MPa, corresponding to the highest values of the activity index, measured at 71.4 % and 75.2 %, respectively. Under standard curing conditions, the hydration products of cementitious materials at 7 d are ettringite (AFt), calcium silicate hydrate (C-S-H), alumina, ferric oxide, monsulfate (AFm), calcium hydroxide (Ca(OH)2), and calcium silica (CS). In the hydration process of 7 d, the exothermic peak and exothermic amount of the 50 min VTIOT cementitious materials are greater than those observed for other grinding times, but lower than those of pure reference cement.

Sustainable End-of-Life Tyre Management: A Comprehensive Analysis of Environmental Impacts and Crumb Rubber Integration in Composite Concretes

The research explores pollution prevention strategies associated with end-of-life tyres (ELTs) through sustainable practices, focusing on repurposing ELTs into crumb rubber (CR) for use in composite concretes for civil engineering applications. Three disposal approaches are considered: recycling into crumb rubber for use in cement composites to enhance acoustic properties, incineration for cement production, and landfill disposal. The study aims to assess the environmental impact of each method, particularly in terms of carbon dioxide (CO2) emissions during the recycling phase, utilizing the OpenLCA program for a comprehensive life cycle analysis. The primary objective is to provide insights into the sustainability of incorporating recycled rubber in concrete mixes as fine aggregate to improve concrete acoustic and shock absorbance properties. The research also gathers data on CO2 emissions from ELT incineration for cement production and the environmental implications of ELT’s landfill disposal. By comparing these three strategies, the study offers a holistic perspective on the environmental ramifications of ELT management. Notably, a recent study highlights the energy recovery and CO2 emissions from ELT incineration, demonstrating the potential benefits of recycling. The research identifies a gap in existing studies, emphasizing the need to consider the entire life cycle, including the transportation and use stages. Notably, the use stage significantly contributes to environmental impacts, with carbon emissions ranging from 550 to 840 kg CO2 eq., per car tyre. Additionally, a proposed inventory analysis method evaluates greenhouse gas emissions from Portland cement concrete pavement construction, revealing that raw material production accounts for most emissions. The findings of this research are providing valuable insights for policymakers, industry professionals, and environmentalists aiming for sustainable practices in the construction sector. By allocating a fraction of tyre production CO2 emissions to obtain raw material for concrete composites, the study suggests a potential avenue for reducing environmental impact. Further calculations using the OpenLCA program may refine these recommendations.

High-volume fly ash self-compacting concrete for coastal constructions: A sustainable development solution

This article presents the research results on the effectiveness of applying high-volume fly ash self-compacting concrete (SCC) in constructing environmentally influenced structures along the coast of Vietnam. SCC is designed with fly ash replacing 70% and 80% of cement. Technical criteria evaluated include workability, compressive strength, chloride ion permeability, water absorption, and dry bulk density of SCC. Additionally, the energy consumption, environmental emissions, and production costs of high-volume fly ash SCC are also assessed. The results show that SCC with 70% and 80% fly ash replacement by weight meets construction requirements, with compressive strengths at 28 days reaching 25.1 MPa and 21.2 MPa, and at 90 days reaching 49.4 MPa and 28.3 MPa respectively; chloride ion permeability is very low, electrical resistivity at 28 days is 690C and 539C; water absorption at 28 days is approximately 2.3% and 2.6%; dry bulk density at 28 days is 2239 kg/m3 and 2225 kg/m3. Compared to conventional concrete with equivalent compressive strengths of 20 MPa and 25 MPa (BT200, BT250), using high-volume fly ash SCC with 70% and 80% fly ash replacement results in energy consumption reduction by 45.28% and 53.45% respectively; CO2, NOx, SOx emissions are reduced by (52.41%, 54.26%, 53.95%) and (62.21%, 64.33%, 64.13%); material production costs decrease by 15.14% and 17.16% respectively. Utilizing high-volume fly ash SCC as a solution for coastal constructions proves to be technically feasible, cost-effective, environmentally friendly, and sustainable.

Investigation of structural, optical, electrical, thermoelectric and optoelectronic properties of undoped ZnO, Sb-doped ZnO and Sb–B co-doped ZnO thin films

Pure ZnO (Zinc oxide), 1 % Sb (antimony) doped ZnO (Zn0.99Sb0.01O), and 1 % Sb–1% B (boron) co-doped ZnO (Zn0.98Sb0.01B0.01O) solutions were prepared using the sol-gel method. These solutions were deposited as thin films on glass and Si (silicon) substrates via dip coating and spraying methods. In this study, doping ZnO with low amounts of Sb and B provided the conversion of the n-type semiconductor ZnO into a p-type semiconductor. The produced thin films were pure and had wurtzite ZnO polycrystalline structure. The nanodot morphology of ZnO turned into a mixture of nanodot and nanorod structures with only Sb doping. Moreover, the band gap energy of ZnO decreased from 3.26 eV to 3.24 eV with Sb doping and to 3.23 eV with Sb and B co-doping, accompanied by a decrease in optical transmittance depending on film thickness. All samples exhibited diode characteristics. According to the created Au/ZnO–Zn0.99Sb0.01O – Zn0.98Sb0.01B0.01O/Si diodes, it was understood that the ideality factor, barrier height, and serial resistance of ZnO material decreased with doping. Especially, the ideality factor, barrier height, and serial resistance of the ZnO sample decreased from 4.95, 6.80 eV, and 1.42 × 105Ω to 4.35, 6.25 eV, and 2.60 × 103Ω, respectively, with Sb and B co-doping. The photovoltaic performance of 1 % Sb-doped thin film increased 100 times compared to pure ZnO, reaching the efficiency from 0.006 to 0.600. However, the most suitable material for use as a photodiode was found to be the 1 % Sb–1% B co-doped sample. While the leakage current of this sample is around −8.0 × 10−5 A at −3 V under 100 mW/cm2 light, it is 9.5 × 10−8 A at −3 V in the dark. Furthermore, the 1 % Sb-doped thin film exhibited the best performance as a thermoelectric material at 600 K, achieving a figure of merit (ZT) of 0.00052. Overall, co-doping with Sb and B enhanced the optical, electrical, and structural (more homogeneous and less surface roughness) properties of ZnO, while improving its optoelectronic functionality such as photodiode. On the other hand, thermoelectric and solar cell properties of ZnO were enhanced with only 1 % Sb doping. A hybrid energy system containing thermoelectric and solar cells was produced cheaply and simply for wide application areas with this study. Moreover, with such a low doping amount, p-type material production was achieved, and important physical properties of the ZnO material were improved.

Developing Teaching Material Used Project-based Learning to Improve Student's Research Skills

This research is intended to develop teaching materials for learning theories courses and test the feasibility of the learning materials products. This research seeks to uncover problems and challenges in learning theories courses from the perspective of lecturers and students. The subjects of this study are students and lecturers of the master program in Islamic Religious Education, Faculty of Tarbiyah and Teacher Training, Universitas Islam Negeri Walisongo Semarang. This research applies a 4D development model to develop teaching materials, which includes four stages: defining, design, development, and dissemination. Researchers use questionnaires and focus group discussions involving lecturers and students. The result of the development in this study is teaching materials of project-based learning teaching materials for learning theories courses. Based on expert validation tests, material experts, curriculum experts, and media design experts declare that teaching materials for project-based learning theories courses are feasible with a scoring average of 81,79%. After being applied to the learning theories course, out of 60 students, 75.17% strongly agreed, 22.17% agreed, and 2.67% disagreed that the teaching materials using Project-Based Learning improved student research skills and helped students more easily understand the course. From the lecturer's point of view, using Project Based Learning (PjBL) in learning theory courses can allow students to learn actively, collaborate with classmates, and develop better research skills. Therefore, implementing PjBL in learning theory courses can effectively improve the quality of learning and student understanding.