American Society For Testing And Materials Research Articles

Structure and morphology of chars and activated carbons obtained from thermal treatment of coal and biomass origin materials, including their wastes: Results from the ICCP Microscopy of Carbon Materials Working Group

This paper describes the evaluation of petrographic textures in char and activated carbon derived from coal, coal by-products and biomass, formed during carbonization and activation processes. This work represents the results of interlaboratory exercises from 2016 to 2022 of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology. The interlaboratory exercises were run on photomicrograph samples. For textural characterization of carbon materials, the existing American Society for Testing and Materials (ASTM) classification system for metallurgical coke was applied. Morphological differences were evaluated in 29 carbon material types, including 22 char samples, and 7 activated carbon (AC) samples obtained experimentally using conventional direct/indirect and microwave heating technologies. This approach gives an extended view on the identification of microporous carbons, and how a certain heat treatment develops a certain optical texture and structure in a raw material. The requested evaluation of carbon materials was related to their porosity, origin, extent, and characteristics, which are particular to each carbon material type. Because carbon matrices can form a wide range of optical textures during heat treatment it is important to demonstrate which carbon occurrences will have a crucial role in industrial applications dominated by adsorption phenomena.The interlaboratory exercises included 17 participants from 14 laboratories. Four sets of digital black and white and colour photomicrographs were distributed, which in total comprised 184 fields of different types of carbon material. The results were evaluated based on four levels: (i) optical texture (isotropic/anisotropic), (ii) optical type and size (punctiform, mosaic, fiber, ribbon, domain), iii) morphology (porous, non-porous/massive), and (iv) particle origin (precursor type).The statistical method applied to evaluate the results was based on “raw agreement indices”. Comparative analyses of the average values of the level of overall agreement showed homogeneity in the results, the mean value was 89%, with a minimum value of 87% and a maximum value of 91% for those who participated in at least three out of four exercises.

Potential of rice husk ash as cement alternative in constructing bricks: Utilization for “Gulayan sa Paaralan” program

This research aims to investigate the “Potential of Rice Husk Ash as Cement Alternative in Constructing Bricks: Utilization for ‘Gulayan sa Paaralan’ Program”. The success of this study provides cheaper option of construction materials. The pandemic experience of the Philippines, economic deterioration became a challenge. Prices of prime commodities continuously increases, including the construction industry. Nowadays, there are various cement alternative being utilized inside and outside of the country. Some part here in the Philippines use fly ash as a cement alternative. But fly ash is not readily available in Laguna. That is why the researchers look for an alternative that is readily available, inexpensive and do not harm the environment. In this study, the researchers examine the potential of rice husk ash and they constructed bricks in which they plan to use for the beautification of school’s garden. In accordance with the governing specification of American Standard of State Highway and Transportation Officials (AASHTO) and American Society for Testing and Materials (ASTM), the researchers conducted a standardized laboratory test. After series of test, researchers concluded that rice husk ash is not a significant alternative to cement as it reduce the strength and durability of the brick made out of it. However, since the chemical composition, fineness test, and water absorption test of rice husk ash and rice husk ash bricks passed the requirements of American Society for Testing and Materials, the researchers inferred that rice husk ash could still be used as additive in creating a decorative bricks.

Sustainable production of eco-friendly roofing tile using methyl ester residue as the alternative binder – A preliminary study

Making full use of industrial by-products is an effort to achieve ‘zero waste’ and promote greener development. Methyl ester residue (MER) is a waste commonly found in oleochemical manufacturers, such as palm oil mills. Contrary to conventional cement and clay, MER was employed as an alternative binder to fabricate a novel eco-friendly roofing tile, henceforth referred to as MER-RT. Parameters tested were transverse strength, water absorption, sulfate resistance, and fire resistance. During the optimization phase, a range of 6–11% of MER was mixed with a fixed composition of fly ash and fine sand, compacted and cured at 190° C for 12–48 hours. Considering the electrical energy consumption, the optimal curing duration chosen was 24 hours as this MER-RT achieved a dry transverse strength of 4112 N whereas curing for an additional 18 hours further contributed to only 16% strength gain. The optimal MER-RT was found to contain 10% MER as it showed the highest dry transverse strength (6410 N), the highest wet transverse strength (3681 N) and the lowest water absorption percentage (2.67%), meeting the American Society for Testing and Materials (ASTM) standards. Besides exhibiting minimal corrosion under the sodium sulfate test, the optimal MER-RT was non-flammable and did not undergo structural changes when exposed to fire. The study reveals the potential of both MER and fly ash as green binders and fillers for roof tiles, despite their origins as industrial waste.

Experimental and molecular dynamics simulation based investigation to understand tribological performance of graphene reinforced thermoplastic polyurethane (Gr/TPU) nanocomposites

Ongoing innovative research in tribology aims to develop high-performance polymer nanocomposite (PNC) materials that offer significant improvements in efficiency, reliability, and durability across various engineering systems. Selection of appropriate nanoreinforcements is crucial for maximizing the tribological behavior in PNCs. The primary objective is to investigate how various factors, such as graphene (Gr) loadings, processing techniques, normal loading, and sliding velocity influence the tribological behavior of thermoplastic polyurethane (TPU) and graphene reinforced thermoplastic polyurethane (Gr/TPU) nanocomposites using molecular dynamics (MD) simulation and experiments. Nanocomposite materials fabricated by ultrasonication methods, test specimens are prepared in appropriate dimensions as per ASTM (American Society for Testing and Materials) and DIN (Deutsches Institut für Normung) standard. MD simulations are conducted on the developed plate and rod models under different sliding velocity, pressing and stabbing depth conditions to understand fundamental insights into the friction and wear mechanisms of Gr/TPU nanocomposites at the atomic level. Morphological studies using scanning electron microscopy (SEM) micrographs indicate no case of Gr agglomeration up to 3 wt% Gr/TPU nanocomposite. Energy dispersive spectroscopy (EDS) analysis confirms presence of Carbon (c), Nitrogen (N) and Oxygen (O) in Gr/TPU nanocomposites. Finally the obtained results from MD simulation and experiments show a significant trend of similarity.

Post-Treatment and Hybrid Techniques for Prolonging the Service Life of Fused Deposition Modeling Printed Automotive Parts: A Wear Strength Perspective

<div>This study aims to explore the wear characteristics of fused deposition modeling (FDM) printed automotive parts and techniques to improve wear performance. The surface roughness of the parts printed from this widely used additive manufacturing technology requires more attention to reduce surface roughness further and subsequently the mechanical strength of the printed geometries. The main aspect of this study is to examine the effect of process parameters and annealing on the surface roughness and the wear rate of FDM printed acrylonitrile butadiene styrene (ABS) parts to diminish the issue mentioned above. American Society for Testing and Materials (ASTM) G99 specified test specimens were fabricated for the investigations. The parameters considered in this study were nozzle temperature, infill density, printing velocity, and top/bottom pattern. The hybrid tool, i.e., GA–ANN (genetic algorithm–artificial neural network) has been opted to train, predict, and optimize the surface roughness and sliding wear of the printed parts. Results disclose that the minimum surface roughness obtained with GA–ANN was 1.05482 μm for infill density of 68%, nozzle temperature of 230°C, printing velocity of 80 mm/sec, and for concentric type of top/bottom pattern. In extension of this study, annealing was performed on the specimens printed on the optimized results obtained from the analysis at three different temperatures of 110°C, 150°C, and 190°C and for a fixed period of time of 60 min as a post-treatment process to further study the impact of annealing on the surface roughness and wear rate. The surface roughness of the samples showed a discernible improvement as a result of annealing, which can further make significant inroads in automotive industries.</div>

RECYCLING OF ASPHALT PAVEMENT AGGREGATES AND WASTE PLASTIC BOTTLES IN ADDITION TO HOT-MIX ASPHALT PRODUCTION: ADEQUATE RECYCLING RATE

This study focused on the recycling of asphalt pavement aggregates and waste plastic bottles (WPB) in addition to hot-mix asphalt (HMA) production. To achieve this objective, non-probable sampling methods were used to gather samples from the study locations. Crushed stone aggregate (CSA), bitumen, mineral filler, reclaimed asphalt pavement aggregate (RAPA), and WPB were the ingredients employed based on the requirements in the standard specification for asphalt concrete production. Initially, the Marshall Stability Test was then carried out using CSA with 6% and bitumen levels of 4.0, 4.5, 5.0, 5.5, and 6% by weight of the total mix to ascertain what the bitumen content should be with RAPA with replacement rates of 10, 20, and 30% and that of WPB with 2, 6, 8, 10, 12, and 14%. In the Marshall Stability Test, which consisted of three trials of 195 samples and 60 mix designs, 45 were for the control mix and 150 for the replacement proportion. In the Marshall Stability Test, the ideal value for CSA was 5.1%; for RAPA, 5.1%; and for WPB, 7.7, 5.5, 5.4, 5.0, 5.5, and 5.4% optimum bituminous content (OBC). 20% RAPA and 10% WPB by weight of OBC in the stability-modified asphalt mix satisfies Ethiopian Road Authority (ERA) and American Society for Testing and Material (ASTM) specifications for all qualities tested. Finally, for improved asphalt mix performance, a combined 70% CSA, 20% RAPA, and 10% WPB should be used in asphalt mixes at 5.0% OBC. These experimental Marshal Stability Test findings satisfy the necessary specifications of ERA and ASTM for all tests used in HMA production. Thus, this proportion is strongly advised.

Modeling and analysis of TiO2 filler's impact on specific wear rate in flax fiber-reinforced epoxy composite under abrasive wear using Taguchi approach

PurposeThis study explores how titanium oxide (TiO2) filler influences the specific wear rate (SWR) in flax fiber-reinforced epoxy composites (FFRCs) through a Taguchi approach. It aims to boost abrasive wear resistance by incorporating TiO2 filler, promoting sustainable and eco-friendly materials.Design/methodology/approachThis study fabricates epoxy/flax composites with TiO2 particles (0–8 wt%) using hand layup. Composites were tested for wear following American Society for Testing and Materials (ASTM) G99-05. Statistical analysis used Taguchi design of experiments (DOE), with ANOVA identifying key factors affecting SWR in abrasive sliding conditions.FindingsThe study illuminates how integrating TiO2 filler particles into epoxy/flax composites enhances abrasive wear properties. Statistical analysis of SWR highlights abrasive grit size (grit) as the most influential factor, followed by normal load, wt% of TiO2 and sliding distance. Grit size has the highest effect at 43.78%, and wt% TiO2 filler contributes 15.61% to SWR according to ANOVA. Notably, the Taguchi predictive model closely aligns with experimental results, validating its reliability.Originality/valueThis paper integrates TiO2 filler and flax fibers to form a novel hybrid composite with enhanced tribological properties in epoxy composites. The use of Taguchi DOE and ANOVA offers valuable insights for optimizing control variables, particularly in natural fiber-reinforced composites (NFRCs).

Biodegradability and Water Absorption of Macadamia Nutshell Powder-Reinforced Poly(lactic Acid) Biocomposites

This study investigates the biodegradability and water absorption properties of Macadamia nutshell powder and poly(lactic acid) (PLA) biocomposites using a Design of Experiments (DOE) approach. The influences of processing methods, the Macadamia nutshell powder’s weight content, and the powder’s condition are studied. A biodegradability test is performed in accordance with the American Society for Testing and Materials (ASTM) D5338-11 by burying the test specimens in wet garden soil at a controlled temperature of 50 °C and 100% humidity. The specimens obtained by counter-rotating processing exhibit varying weight loss patterns with an increasing powder weight content, while the specimens obtained by co-rotating processing demonstrate consistent behaviour. This study highlights the complex nature of PLA biodegradation, which is affected by diverse factors such as test conditions and environments, thereby contributing to a deeper understanding of the sustainability implications. A water absorption test is carried out in accordance with ASTM D570-98. It is shown that the water absorption characteristics are predominantly determined by the hydrophilic nature of Macadamia nutshells, with an increased powder weight content leading to higher absorption. Pure PLA, due to its hydrophobic nature, exhibits minimal water absorption. By unravelling the complexities of PLA biodegradation and water absorption in Macadamia nutshell and PLA biocomposites, this study not only advances the understanding of materials’ behaviour but also underscores the potential sustainability implications of utilizing natural resources in composite materials. This research contributes valuable insights to the broader discourse on environmentally friendly materials and their role in promoting sustainable practices.

Measuring Color Index of Transformer Oil–Enabling Single-Wavelength Spectroscopy With Artificial Neural Network-Fuzzy Logic Model

Conventionally, the color index of transformer oil is determined by a color comparator based on the American Society for Testing and Materials (ASTM) D 1500 standard. The equipment requires humans to operate, which leads to human error and limited number of samples tested per day. This work proposes the utilization of single-wavelength spectroscopy with 405 nm laser diode using artificial neural network (ANN) to determine the color index of transformer oil. Two ANN models were developed using data collected from 50 oil samples with different optical pathlengths of 1 to 10 mm, and laser output powers of 1 to 15 mW. The first model classified the input into different color indices and another model correlated the input parameters through regression analysis to determine the color index. A hybrid ANN-fuzzy logic model was also developed to improve the color index prediction. The root-mean-squared error (RMSE) obtained from the prediction by ANN regressor and ANN classifier are 0.5602 and 0.6416, respectively. The hybrid ANN-fuzzy logic model improves the RMSE especially for optical pathlengths <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&lt;$</tex-math> </inline-formula> 5 mm, which is required for measuring samples with high color index. This proposed method reduces the dependency on complex optoelectronic hardware to obtain highly accurate results. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Unlike the conventional testing method for color index of transformer oil that requires human observation, the findings of this study enables the possibility of compact and smart portable device through the utilization of single wavelength spectroscopy with machine learning models. With no human involvement, more computational power with lesser hardware dependency, the maintenance cost and error can be reduced. This proposed method can potentially be applied to measure the color of other amber-colored liquid products such as olive oil, honey and others.

Optimizing gypsum particleboard properties: An orthogonal analysis of pennisetum giganteum and phosphogypsum composites

Gypsum particleboard is attracting attention in the construction industry due to its excellent properties. However, the traditional raw materials for gypsum particleboard are facing a shortage of supply. In this study, we innovatively utilized bulk solid waste Phosphogypsum and Pennisetum giganteum for the first time to manufacture gypsum particleboard. This approach not only effectively addresses the issue of insufficient supply of traditional raw materials for gypsum particleboard but also provides a new pathway for the resource utilization of phosphogypsum. Through an orthogonal experimental design, we focused on optimizing the gypsum particleboard formulation, concentrating on factors such as density, the ratio of Pennisetum giganteum to gypsum (grass-plaster ratio), the ratio of water to gypsum (water-plaster ratio), and the size of the particles. The study determined that the optimal formulation parameters were a density of 1.2 g/cm³, a grass-plaster ratio of 0.20, a water-plaster ratio of 0.25, and a particle mesh number of 14. Under these conditions, the gypsum particleboard exhibited excellent performance, characterized by a static flexural strength of 6.5 MPa, a modulus of elasticity of 2010 MPa, an internal bond strength of 0.4 MPa, a 24-hour water-absorption thickness expansion rate of 2.2%, and an equilibrium moisture content of 1.6%, all meeting the American Society for Testing and Materials (ASTM) Standard D1037. These findings indicate that gypsum particleboards made with Pennisetum giganteum and phosphogypsum can perform comparably to those made with conventional materials. Additionally, a performance prediction model was established using Multiple Linear Regression Analysis (MLRA). The analysis revealed a significant linear relationship between the independent and dependent variables in the model, with the Analysis of Variance (ANOVA) significance levels being less than 0.05, demonstrating statistical significance. This result provides a theoretical basis for the future development of high-performance gypsum particleboard.

Comparative analysis of petroleum products from artisanal refineries and standard products

Comparative analysis of petroleum products from artisanal refineries and standard products

Comparative Physiognomies of Crude Oil and Petroleum Products from Kwale in Delta State, Nembe, and Kula in the Niger Delta Region of Nigeria

This paper investigated selected physiognomies of crude oil and petroleum products collected from Kali in Delta State, Kula in Rivers State, and Nembe in Bayelsa State in the Niger Delta Region of Nigeria using the standard procedure of the American Society for Testing and Materials (ASTM). The result shows that the crude oils were different in terms of API gravity and specific gravity. API gravity of 52.17, 46.31, and 45.38 for Kwale, Kula, and Nembe respectively. This shows that they are not heavy crude oil. The low water content and low viscosity of the crude oils lower the risk of pipe and container corrosion and flow difficulty. The result of density, specific gravity, viscosity, and kinematic viscosity shows the value of those parameters increase from light fraction to heavy fraction. The pour point and flash point recorded for light fractions were lowered than that of heavy fractions, for the three samples of crude oil. The flash point is 61.30 C, -340 C, and -310 C while the pour point is 9 0 C, 20 C, and 6 0 C respectively for Kwale, Kula, and Nembe. The level of heavy metal analyzed was generally low but metals such as nickel and vanadium and other elements such as Nitrogen, Oxygen, and Sulphur were in abundance in the samples of the crude oil. The results are discussed in terms of importance and implication.

A novel systematic approach for robust numerical simulation of carbon fiber-reinforced plastic circular tubes: Utilizing machine-learning techniques for calibration and validation

Developing a reliable and robust finite element model of a carbon fiber-reinforced plastic (CFRP) composite structure is investigated by using the LS-DYNA solver and Python. This study tries to provide a systematic numerical approach to cover the principal impediment to adaptation of composite energy absorbers, that is the lack of a reliable predictive method. The proposed procedure aims to further the understanding of advanced composite structures’ behavior during the crash phenomenon by developing an accurate finite element model. To do so, the mechanical properties of the material were extracted from American Society for Testing and Materials (ASTM) standard test methods, followed by experimental investigation of circular CFRP tubes undergoing quasi-static loading. A numerical simulation framework was then utilized to scrutinize the effectiveness of simulation parameters on the crushing mechanism. Finally, a systematic approach based on machine learning techniques was performed to adjust non-physical modeling parameters for further calibration and validation. In this regard, a versatile Python code was developed to automate pre-processing, processing, and post-processing steps. The code also provides a groundwork to perform machine learning techniques. Interestingly, the numerical and experimental results were highly correlated with a correlation coefficient of almost 90%. Additionally, several non-physical numerical parameters were found to be inactive, while some else were identified as effective parameters, and their corresponding effectiveness was quantitatively extracted and discussed for the first time in the literature.

Formulation and evaluation of bio-grease from the blend of chemically modified rice bran oil and Calophyllum inophyllum oil

Vegetable oils are a highly promising alternative to produce various lubricants, owing to their biodegradability and eco-friendliness. In comparison to mineral oil, these oils possess a higher flash point and viscosity index, along with superior lubricating properties. Additionally, most of the vegetable oils are easily accessible in local markets in India. However, their industrial application is limited by poor thermal and oxidative stability, which can be addressed through chemical modification, the addition of appropriate additives, or by blending these oils. Greases, characterized by their semi-solid consistency, are widely used lubricants. Most of the grease production is based on mineral oils as base oil and lithium soap as a thickener. These materials are not only non-biodegradable but also scarce and have health implications. Consequently, biodegradable grease represents an eco-friendly and healthy alternative. Grease made using vegetable oils with the required properties has the potential to bring about revolutionary changes. The present work focuses on the feasibility of using chemically modified blended rice bran oil (RBO) and Calophyllum inophyllum oil (CIO) as a bio-lubricant. The oils undergo a two-step modification process, involving a transesterification reaction followed by epoxidation. Significant improvements have been observed in the chemical properties (acid, peroxide, and iodine values) of transesterified epoxidized rice bran oil Calophyllum inophyllum oil mixture–50:50 (ETRCIO) when compared with Unmodified Rice bran oil Calophyllum inophyllum oil mixture–50:50 (RCIO). The acid value, peroxide value, and iodine value improved by 91.66%, 87.08%, and 15.78% respectively. The rheological, tribological, and chemical properties of the blended samples have been evaluated and compared to pure oils using American Society for Testing and Materials (ASTM) and Indian Standards (IS). Additionally, ETRCIO was used to develop a bio-grease, and its tribological properties were extensively analyzed. The mean coefficient of friction (COF) and wear scar diameter (WSD) of the ETRCIO grease sample improved by 10.20% and 29.32% respectively when compared with that of commercially available grease. These findings indicate that the ETRCIO bio-grease exhibits superior tribological properties in comparison to commercially available grease.

A STUDY OF THE RELATIONSHIP BETWEEN THE OCTANE NUMBER AND THE CHEMICAL COMPOSITION OF REGULAR, MIDGRADE, AND PREMIUM GASOLINE

The present  study was conducted at Zakho City in Northern Iraq to evaluate three different types of gasoline: Regular, Midgrade, and Premium. These types of gasoline are categorized based on their octane rating, which was measured to verify their classification. The results showed that the initial classification was accurate, with respective values of 87.5, 89.8, and 91.1. The  study evaluated the three grades of gasoline available  at Zakho Gas Stations in Northern Iraq, including Regular, Midgrade, and Premium. The study  also compared the chemical composition of the three gasoline grades in terms of aromatics, olefin, sulfur content, and oxygen content. All the three gasoline grades met the American Society for Testing and Materials (ASTM) standard for chemical composition, and all had acceptable specific gravities. However, Midgrade gasoline is not recommended for use during the summer due to its high Reid vapor pressure (RVP) value, low Initial boiling point (IBP), and final boiling point( FBP). In general, the  study showed that the Regular and Premium gasoline types sold in North  of Iraq meet international quality standards. However, Midgrade gasoline is not recommended for use during the summer due to its high RVP value, low IBP, and FBP, which can lead to increased volatility and environmental pollution, Moreover, using this type of gasoline may cause problems with the car engine.

Development of South Africa Macadamia Nuts and its Utilization for Biodiesel Production

Demands for energy are rising as the world's population expands. To meet these demands, fossil fuels have been overused, yet this over reliance on them has led to their depletion. The usage of fossil fuels has also significantly contributed to the release of greenhouse gases, which is a serious environmental concern. Sustainable energy is therefore environmentally friendly and financially sound. Petro-diesel can be replaced by biodiesel because it is biodegradable and less hazardous. Biofuel is any fuel produced from biomass, which can be either animal fats or waste, plant or algae material as a feedstock. Biomass benefits in producing fuels which helps to lessen the demand for petroleum fuel and products. Petroleum fuel and gas increase the greenhouse gas emissions profile of the transportation sector. The Republic of South Africa (RSA) is the 14th world's largest emitter of greenhouse gases. This is due to the emissions resulting from burning and heavy reliance on coal. Since biofuel can be produced domestically from natural sources like soybeans, rapeseed, macadamia nuts, coconuts, and even leftover cooking, it has the potential to serve as a remarkable substitute for the commonly used petroleum-derived diesel fuel. This study addresses the historical development of macadamia nuts with a focus on the South African Macadamia Nuts (SAMN) industry, its origin, and as a feedstock for biodiesel production. The generation and classification of biodiesel, physicochemical properties, biodiesel standards, and both American Society for Testing and Materials (ASTM), European Committee for Standardization (EN 14214), and South African biodiesel framework standards are discussed. Furthermore, the biodiesel blending requirements, techniques, and benefits were outlined. Finally, the biodiesel regulatory framework of SA and biodiesel framework as per the Biodiesel Task team (BTT) was examined.

Physicochemical characterization of briquette fuel produced from cocoa pod husk case of Cameroon

This paper aims to prepare and evaluate the physicochemical and energetic properties of briquette fuel made from cocoa pod husk. For briquette preparation, cocoa pod husk was dried, carbonised, crushed, mixed using binder, compacted, and finally the briquettes obtained were dried. The briquettes produced were characterised by proximate analysis, ultimate analysis, infrared spectroscopy, and thermogravimetric analysis using the American Society for Testing and Materials (ASTM) and the European Committee for Standardisation (CEN) standards. The results from the proximal analysis obtained (10.5%), (6.5%), (34.7%), and (58.8%), respectively, for moisture content, ash content, volatile matter, and fixed carbon, are satisfactory values. The results from the ultimate analysis found are 53.2%, 5.2%, and 34.4%, respectively, for carbon, hydrogen, and oxygen content, while H/C and O/C gave 1.17 and 0.48, respectively. The Higher Heating Value (17.941 MJ/kg) proved high thermal stability, with the highest mass loss of 32.50% at 361°C due to the high extractive content and the aromatic structure of the polymer. The presence of C-O, CC, CHx, and OH groups was noticed, while the fuel value index (FVI) and impact resistance index (IRI) showed 1104% and 125%, respectively. These results indicated that the abundance of these residues in landfills could serve as an alternative fuel energy source with environmental friendly features and contribute to the economic growth of the country.

Cymbopogon nardus Leaf Ash as an Alternative Material for Enhancing Concrete Strength

Numerous waste materials containing calcium and silica have been adopted as partial cement substitutes. This practice is intended to reduce the environmental impact of cement production, specifically in terms of carbon dioxide (CO2) emissions. However, plantation waste, specifically waste from Cymbopogon nardus leaf, has not been completely exploited. The presence of silica in C. nardus leaf ash (CNLA) presents an opportunity to partially replace cement in concrete. The purpose of this study is to determine the effect of substituting CNLA at 0%, 5%, 10%, and 15% as a partial replacement for cement on the compressive and tensile strengths of concrete after 28 days of curing. For testing purposes, 15 cm × 30 cm cylindrical concrete specimens were formed. The investigation was conducted following ACI 211.1-91 (American Concrete Institute) and ASTM (American Society for Testing and Materials) standards. The required compressive strength for the concrete was 17.00 MPa. The results of the study indicate that the addition of CNLA to cement at concentrations of 0%, 5%, 10%, and 15% resulted in compressive strengths of 21.56, 21.12, 22.58, and 17.88 MPa, respectively. The results of the split tensile strength test were 2.43, 2.72, 2.87, and 3.18 MPa, respectively. According to the findings of this study, increasing the amount of CNLA in cement by 10% can increase the compressive and tensile strengths of concrete. In addition, as the percentage of CNLA exceeds 10%, the workability of the concrete decreases, posing challenges in attaining the targeted strength of the concrete.

Utilization of microalgae for agricultural runoff remediation and sustainable biofuel production through an integrated biorefinery approach

Generally wastewater such agricultural runoff is considered a nuisance; however, it could be harnessed as a potential source of nutrients like nitrates and phosphates in integrated biorefinery context. In the current study, microalgae Chlorella sp. S5 was used for bioremediation of agricultural runoff and the leftover algal biomass was used as a potential source for production of biofuels in an integrated biorefinery context. The microalgae Chlorella sp. S5 was cultivated on Blue Green (BG 11) medium and a comprehensive optimization of different parameters including phosphates, nitrates, and pH was carried out to acquire maximum algal biomass enriched with high lipids content. Dry biomass was quantified using the solvent extraction technique, while the identification of nitrates and phosphates in agricultural runoff was carried out using commercial kits. The algal extracted lipids (oils) were employed in enzymatic trans-esterification for biodiesel production using whole-cell biomass of Bacillus subtilis Q4 MZ841642. The resultant fatty acid methyl esters (FAMEs) were analyzed using Fourier transform infrared (FTIR) spectroscopy and gas chromatography coupled with mass spectrometry (GC–MS). Subsequently, both the intact algal biomass and its lipid-depleted algal biomass were used for biogas production within a batch anaerobic digestion setup. Interestingly, Chlorella sp. S5 demonstrated a substantial reduction of 95% in nitrate and 91% in phosphate from agricultural runoff. The biodiesel derived from algal biomass exhibited a noteworthy total FAME content of 98.2%, meeting the quality standards set by American Society for Testing and Materials (ASTM) and European union (EU) standards. Furthermore, the biomethane yields obtained from whole biomass and lipid-depleted biomass were 330.34 NmL/g VSadded and 364.34 NmL/g VSadded, respectively. In conclusion, the findings underscore the potent utility of Chlorella sp. S5 as a multi-faceted resource, proficiently employed in a sequential cascade for treating agricultural runoff, producing biodiesel, and generating biogas within the integrated biorefinery concept.Graphical

Utilization of Rice Field Conch Shells as a partial substitution of Cement and Fine Aggregate for Split Tensile Strength of Concrete

Aceh is one of the provinces in Indonesia which has a very large area of rice field production. However, there are many pests that hinder agriculture in Indonesia. One of them is the rice field conch shells which has the potential to cause very high losses to the rice crop harvest. The aim of this research was to determine the ratio of the split tensile strength of concrete using rice field conch shells as a partial replacement for cement and fine sand against normal concrete by 0%, 5%, 10%, and 15%. In addition, it was also seen the effect of immersing concrete specimens using rice field conch shells substitution in tap water and water collected from paddy's farm. This study used the ACI (American Concrete Institute) 211.1-91 and ASTM (American Society for Testing and Materials) methods. The specimens consisted of cylinders with dimensions of 15 cm x 30 cm, totaling 40 specimens with a design concrete compressive strength of 17.00 MPa. The curing of the specimens was carried out using tap water and water collected from paddy's farm for 28 days in the soaking tub. The results showed that 5% substitution of rice field conch shells in cement and fine sand using the tap water immersion method showed a 3% increase in the tensile strength of concrete in comparison with normal concrete. Meanwhile, immersion using the water collected from paddy’s farm method showed a decrease in the value of the split tensile strength of the concrete.