Conventional Mineral Research Articles

Bio-lubricants as viable replacements for mineral oils in automotive engines: A review

This review paper explores the potential of bio-lubricants as sustainable alternatives to conventional mineral oils for the lubrication of automotive engines. Bio-lubricants, which are derived from renewable sources such as vegetable oils, provide substantial environmental advantages, such as reduced toxicity and biodegradability. The review summarizes the results of recent research, emphasizing the superior lubricity, oxidative stability, and wear resistance of bio-lubricants, particularly those that have been formulated with additives to improve performance. The chemical structure and fatty acid composition of vegetable oils, including soybean, palm, and cottonseed oils, are the subject of discussion, as they have a significant impact on their lubrication properties. The efficacy of advanced modeling techniques, such as genetic algorithm (GA) and artificial neural networks (ANN), in the prediction and optimization of bio-lubricant formulations is assessed. Despite their promising qualities, bio-lubricants encounter obstacles such as fluctuations in raw material quality and increased production costs. The review underscores the necessity of ongoing research and development to confront these obstacles, with an emphasis on enhancing performance consistency and cost-effectiveness. It is argued that the transition to bio-lubricants is a crucial step in the pursuit of sustainable automotive lubrication, as it reduces dependence on non-renewable resources and mitigates environmental damage. Future research directions and recommendations are suggested to further improve the applicability and adoption of bio-lubricants in the automotive industry.

Clinical and Radiographic Evaluation between Conventional Mineral Trioxide Aggregate and Gel-based Mineral Trioxide Aggregate in Indirect Pulp Therapy: A Randomized Clinical Trial.

Indirect pulp treatment (IPT) is often employed in dentistry as a valuable technique for preserving dental vitality. While mineral trioxide aggregate (MTA) remains a popular choice, the need for materials with shorter setting times, lower costs, and minimized discoloration concerns has led to the exploration of alternative options. To evaluate and compare the radiographic and clinical outcomes of gel-based MTA Kids e-MTA (Kids-e-Dental, Mumbai, India) with MTA (ProRoot MTA, Dentsply Tulsa, Johnson City, TN, USA). A randomized clinical trial was conducted in which participants aged 6-12 years were selected according to inclusion criteria. A sample size of 32 primary molars and young permanent molars with deep caries were treated by IPT with 2 mm ProRoot MTA and e-MTA. The groups were divided into two: group I (ProRoot MTA) and group II (e-MTA), with 16 samples in each group. Clinical and radiographic success, in addition to newly formed dentin thickness, were evaluated regularly at 3, 6, 9, and 12 months. Both groups showed a clinical and radiographic success rate of 100% throughout all follow-up intervals. Analysis of the mean thickness of newly formed dentin at various follow-up intervals revealed no statistically significant difference between the two groups at 3, 6, 9, and 12 months, with p-values of 0.32, 0.33, 0.33, 0.33, and 0.33, respectively. K VB, Dighe SS, Saha R, et al. Clinical and Radiographic Evaluation between Conventional Mineral Trioxide Aggregate and Gel-based Mineral Trioxide Aggregate in Indirect Pulp Therapy: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2024;17(12):1383-1387.

Oxidative Polymerization in Water Treatment: Chemical Fundamentals and Future Perspectives.

For several decades, the methodology of complete destruction of organic pollutants via oxidation, i.e., mineralization, has been rooted in real water treatment applications. Nevertheless, this industrially accepted protocol is far from sustainable because of the excessive input of chemicals and/or energy as well as the unregulated carbon emission. Recently, there have been emerging studies on the removal of organic pollutants via a completely different pathway, i.e., polymerization, meaning that the target pollutants undergo oxidative polymerization reactions to generate polymeric products. These studies have collectively shown that compared to the conventional mineralization pathway, the polymerization pathway allows more efficient removal of target pollutants, largely reduced input of chemicals, and suppressed carbon emission. In this review, we aim to provide a comprehensive examination of the fundamentals of the oxidative polymerization process, current state-of-the-art strategies for regulation of the polymerization pathway from both kinetic and thermodynamic perspectives, and resource recovery of the formed polymeric products. In the end, the limitations of the polymerization process for pollutant removal are discussed, with perspectives for future studies. Hopefully, this review could not only provide critical insight for the advancement of polymerization-oriented technologies for removal of more organic pollutants in a greener manner but also stimulate more paradigm innovations for low-carbon water treatment.

Converting Biochar Into Biochar‐Based Urea Promotes Environmental and Economic Sustainability in Rice‐Wheat Rotation System

ABSTRACTBiochar amendments in rice‐wheat systems are sustainable for reducing GHGs (greenhouse gases) and improving soil health but the widespread adoption of biochar faces economic challenges. To address limitation, a novel biochar‐based urea was formulated for environmental and cost advantages. A pot experiment within a rice‐wheat rotation was conducted to evaluate comparative effects of biochar‐based urea (CKBU), biochar + urea (BCU), and biochar‐based urea + biochar (BCBU) over conventional mineral fertilizer (CKU) on soil ammonia (NH3) volatilization, GHG emissions, soil structure, and crop productivity. Furthermore, fertilizer N fate was tracked using the 15N isotope during wheat season. The results indicated that compared to CKU, CKBU, BCU, and BCBU treatments significantly mitigated NH3 volatilization by 22%–31% during the rice season, and a 19% reduction was observed under the BCBU treatment during the wheat season due to the response of N‐cycling microorganisms. Regarding GHG emissions, the CKBU, BCU, and BCBU treatments significantly decreased the global warming potential (GWP) value by 49%–55% during the rice season and by 26%–45% during the wheat season, compared to CKU. Additionally, CKBU enhanced 15N use efficiency by 29% during wheat season, without affecting the rice season. The economic performance indicated that applying BU alone offered a net economic benefit, whereas biochar amendment led to a net economic loss. However, biochar amendment improved SOC and aggregation structure, with a significant increase in macroaggregate distribution over 50% compared to CKU and CKBU. Therefore, BU with small portions of biochar can be as effective in reducing NH3 emissions and mitigating GHG emissions as the use of a large quantity of biochar. Additionally, the BCBU did not show additional synergistic benefits regarding emission reduction or yield enhancement. Therefore, shifting biochar to BU could be a cost‐effective approach to achieving sustainable productivity in rice‐wheat crop rotation systems.

Quantitative ultrasound imaging reveals distinct fracture-associated differences in tibial intracortical pore morphology and viscoelastic properties in aged individuals with and without diabetes mellitus - an exploratory study.

Diabetes mellitus (DM) is a chronic metabolic disorder that increases fragility fracture risk. Conventional DXA-based areal bone mineral density (aBMD) assessments often underestimate this risk. Cortical Backscatter (CortBS) ultrasound, a radiation-free technique, non-invasively analyzes cortical bone's viscoelastic and microstructural properties. This study aimed to evaluate CortBS's discriminative performance in DM patients compared to DXA and characterize changes in cortical bone microstructure in Type 1 and Type 2 DM (T1DM, T2DM) patients. This in-vivo study included 89 DM patients (T1DM = 39, T2DM = 48) and 76 age- and sex-matched controls. DXA measured aBMD, while CortBS measurements were taken at the anteromedial tibia using a medical ultrasound scanner with custom software. Multivariate analysis of variance assessed the impact of DM type on CortBS and DXA measurement results. Partial least squares discriminant analyses with cross-validation were used to compare the discrimination performance for vertebral, non-vertebral, and any fragility fractures, adjusting for gender, age, and anthropometric parameters (weight, height, BMI). Fractures occurred in 8/23 T1DM, 17/18 T2DM, and 16/55 controls. DXA parameters were reduced in fracture patients, with significant diabetes impact. T2DM was associated with altered CortBS parameters, reduced scatterer density, and larger pores. CortBS outperformed DXA in discriminating fracture risk (0.61 ≤ AUC(DXA) ≤ 0.63, 0.68 ≤ AUC(CortBS) ≤ 0.69). Both T1DM and T2DM showed altered bone metabolism, with T2DM linked to impaired tissue formation. CortBS provides insights into pathophysiological changes in diabetic bone and provided superior fracture risk assessment in DM patients compared to DXA.

Evaluation of Sargassum spp. Oil as a Potential Additive for Biolubricant Formulations

Macroalgae-derived oils offer a sustainable and environmentally friendly alternative to conventional mineral oils and additives in lubricant formulation. Their favorable fatty acid profiles can contribute to mitigating the environmental impacts caused by using fossil-based products. This study evaluates the potential of Sargassum spp. oil, collected from the Mexican Caribbean, as a lubricity-enhancing additive in synthetic base oils. The impact of Sargassum spp. oil on viscosity and tribological performance was analyzed. The results indicated that Sargassum spp. oil has potential as an anti-wear additive since a formulation using 10% v/v Sargassum spp. oil in a synthetic lubricant (PAO6) resulted in a wear scar diameter value of 703.03 ± 15.56 µm, which is about 10% lower than PAO6 used as commercial synthetic control. Additionally, the formulation significantly enhanced the viscosity index, with a value of 169, which was notably higher than the control (137). The parameter of the coefficient of friction was significantly reduced from 0.1 to 0.08 (about 27%) when using the formulation with 10% v/v Sargassum spp. oil. These findings underline the potential of algae oils as additives in synthetic lubricants, promoting a transition towards greener products and reducing the environmental impact derived from conventional formulations of polyalphaolefins and esters.

Mobilization of grassland soil arsenic stores due to agronomic management

The fate of arsenic in mineral soil stores over time is poorly understood. Here we examined arsenic loss over five decades from a managed grassland soil profile through analysing archived material from a long-term slurry (LTS) experiment at Hillsborough, Northern Ireland. A randomized block experiment was established in 1970 where a perennial ryegrass sward was seeded onto the site and subjected to control (no fertilization) and fertilization treatments using conventional (i.e. at farmers recommended application rate) mineral NPK fertilizer, and pig and cow slurry treatments. Soil (0–5, 5–10 and 10–15 cm), slurry applied, and sward off-take was archived each year. A mass-balance calculation found that control soils lost no arsenic down the 15 cm depth soil profile, the NPK treatment had a 10 % loss, while cow slurry caused 25 % loss, and a 35 % loss was observed for pig slurry. For treatments with arsenic loss, removal was linear over the 50 years of study in 2 out of the 3 blocks, with the 3rd block showing little or no change. Principal Component Analysis (PCA) found that arsenic was most positively associated with soil magnesium, manganese and nickel, while negatively associated with pH, organic carbon, phosphorus and silicon. Laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) of soil found that arsenic association with lead mineralogy could potentially explain why there was a gradient in arsenic loss across the experimental plots. Slurry and atmospheric inputs, and sward off-take had little impact on the soil arsenic mass-balance. The findings suggest that leaching loss down the soil profile was the mechanism of loss of arsenic. The applicability of the LTS experimental site arsenic findings to other soils is discussed, as is the implication for the global biogeochemical cycling of those soils.

Comparative Analysis of Cytotoxicity and Odontogenic Differentiation of Novel Bioceramic Material on Human Dental Pulp Stem Cells – An In Vitro Study

ABSTRACT Background and Objective: Bioceramic materials have revolutionized the field of endodontics by successfully transforming the outcomes of pulp therapies. Novel biomaterials are evolving by modifying the conventional mineral trioxide aggregate (MTA) to overcome their existing limitations, the major ones being prolonged setting and cytotoxic radiopacifiers. Dental white portland cement (DWPC) is a novel formulated bioceramic material introduced as an enhanced MTA alternative. This in vitro study aims to investigate the cytotoxicity and odontogenic differentiation of novel formulation DWPC with MTA Angelus, Biodentin (BD) and white portland cement (WPC) on human dental pulp stem cells (HDPSCs). Materials and Methods: HDPSCs were cultured in Dulbecco’s modified eagle’s medium (DMEM) with fetal bovine serum (FBS) and antibiotics at 37°C, 90% humidity in a 5% CO2 incubator. Experimental samples were prepared as disks. The viability of HDPSCs was measured by Mosmann’s tetrazolium toxicity (MTT) assay, and odontogenic potential was assessed using alkaline phosphatase (ALP) activity at 24 hours, 7-, 14-, and 21-day intervals. The mean and standard deviations were statistically analyzed by one-way ANOVA and post hoc Scheffe tests using IBM SPSS Software (IBM statistical package for social sciences) – Version 24.0 with a significance level set as P < 0.05. Results: All four groups tested using MTT assay showed no toxicity and possess odontogenic potential in all the experimental durations. Experimental group DWPC presented with the highest mean cell viability and ALP activity at all intervals followed by WPC, MTA, and BD (P < 0.05). Conclusion: DWPC presented good bioactivity in terms of cell viability and ALP activity. Thus, DWPC could be a promising endodontic material. However, further research is warranted to explore the clinical applicability.

Impaired Bone Tissue Quality Associated with Inflammation in HIV-Immunological Non-Responders: A Cross-Sectional Analysis.

People with HIV (PWH) with poor immune response despite adequate antiretroviral treatment (ART) are susceptible to non-AIDS-related health issues. This study seeks to evaluate bone quality in Immunological Non-Responders (INRs) in comparison to those with proper immune response (IRs) using in vivo microindentation to quantify bone quality, in addition to conventional bone mineral density (BMD) evaluations. A cross-sectional study was conducted at Hospital del Mar in Barcelona from January 2019 to June 2023. Participants were matched in a 1:2-ratio (INRs:IR) based on age, sex, body mass index (BMI), and ART. Participants underwent bone quality assessment using in vivo microindentation, BMD and analysis of bone turnover and inflammation markers. Statistical analyses involved multivariable regression to adjust for potential confounding variables. A total of 159 PWH were included, 53 INRs and 106 IRs. INRs had worse bone quality, with lower median Bone Material Strength index (BMSi) compared to IRs (79 (76-87) vs. 86 (82-89); p<0.001), and similar BMD. INRs shown increased high-sensitive C-Reactive Protein levels with lower 25-(OH)-Vitamin D3. A significant negative correlation between inflammation and bone quality was found, especially noticeable in INRs. Multivariable linear regression shown that INR status is a major predictor of decreased bone quality, regardless of conventional risk factors. INRs condition is significantly associated with higher inflammatory levels, which may contribute to a deleterious effect on bone quality as measured by in vivo microindentation. Further studies are needed to confirm these results and to focus on non-AIDS comorbidities in this subgroup of PWH.

Reprocessing of Aluminum Production Residues by Roasting and Magnetic Separation

Objective: The aim of this work was to contribute for the development of a strategy for the reprocessing of red mud and marginal bauxite for iron recovery by magnetic roasting. Theoretical Framework: Red mud and marginal bauxite contain a considerable amount of iron, but it is not possible to recover this iron content with conventional mineral concentration techniques. Magnetic roasting is a process applied to alter the magnetic properties of minerals, typically aimed at the conversion of weakly magnetic iron oxides, such as goethite and hematite, into magnetite, a strongly magnetic phase. After roasting, iron can be recovered by magnetic separation even at low field intensities. Method: To achieve the purpose of this work, marginal bauxite and red mud samples were prepared, characterized chemically and mineralogically, roasted in a rotary kiln at different temperatures and with or without the addition of coke or hydrogen as reducing agents; and subjected to magnetic separation. The products of the roasting pre-treatment were characterized in terms of mineralogical composition by X-ray powder diffraction to assess the phase changes that occurred. Results and Discussion: The results obtained revealed that magnetic roasting is a promising technique to recover iron from marginal bauxite and red mud. Although recoveries higher than 90% were achieved, the selectivity of magnetic separation was low, indicating that Al was also being recovered in the magnetic product. Further conditions may be investigated. Research Implications: Tons of red mud are disposed of in tailing dams, and tons of marginal bauxite are stored in ore piles. Both pose environmental risks that might be significantly reduced if a strategy for reprocessing these aluminum production residues is applied. Originality/Value: The relevance and value of this research are evidenced by the promising results achieved, that showed that it is possible to recover iron from red mud and marginal bauxite by combining roasting pre-treatment and magnetic separation.

Treating Tropical Soils with Composted Sewage Sludge Reduces the Mineral Fertilizer Requirements in Sugarcane Production

Conventional mineral fertilization (CMF) is a common practice in infertile sugarcane-cultivated tropical soils, increasing production costs and environmental concerns. Combining CMF with composted sewage sludge (CSS) could be a sustainable strategy. We aim to evaluate changes in soil chemical properties, macro- and micronutrient concentrations in the soil surface (Ap1; 0–25 cm) and subsurface (Ap2; 25–50 cm) horizons, after CSS application with or without CMF in sugarcane cultivation (first and second ratoon cane). Eleven treatments, featured by CSS increase rates and mixed with CMF at different concentrations, were tested in the first ratoon; during the second, the CSS residual effect was evaluated. Applying CSS in sugarcane-cultivated soils, improved the following: (i) soil organic matter, pH, the sum of bases, cation-exchange capacity, and base saturation; (ii) overall nutrient concentrations (P, K, Ca, Mg, B, Cu, and Zn). The treatments showing the best performances were those with 5.0 Mg ha−1 of CSS. Composted sewage sludge has the potential for use as an organic natural fertilizer reducing the need for CMF. When applied in infertile tropical soils, additional positive effects can be achieved, such as decreasing production costs and providing socio-economic benefits.

Microbe-Friendly Plants Enable Beneficial Interactions with Soil Rhizosphere Bacteria by Lowering Their Defense Responses.

The use of plant growth-promoting rhizobacteria presents a promising addition to conventional mineral fertilizer use and an alternative strategy for sustainable agricultural crop production. However, genotypic variations in the plant host may result in variability of the beneficial effects from these plant-microbe interactions. This study examined growth promotion effects of commercial vegetable crop cultivars of tomato, cucumber and broccoli following application with five rhizosphere bacteria. Biochemical assays revealed that the bacterial strains used possess several nutrient acquisition traits that benefit plants, including nitrogen fixation, phosphate solubilization, biofilm formation, and indole-3-acetic acid (IAA) production. However, different host cultivars displayed genotype-specific responses from the inoculations, resulting in significant (p < 0.05) plant growth promotion in some cultivars but insignificant (p > 0.05) or no growth promotion in others. Gene expression profiling in tomato cultivars revealed that these cultivar-specific phenotypes are reflected in differential expressions of defense and nutrient acquisition genes, suggesting that plants can be categorized into "microbe-friendly" cultivars (with little or no defense responses against beneficial microbes) and "microbe-hostile" cultivars (with strong defense responses). These results validate the notion that "microbe-friendly" (positive interaction with rhizosphere microbes) should be considered an important trait in breeding programs when developing new cultivars which could result in improved crop yields.

Alkylsulfonic acid functionalized aluminoborate: A highly efficient and regioselective solid acid catalyst for ring-opening addition of epoxide under solvent-free condition

Functionalized solid acid material has more accessible active surface and therefore is usually considered as an important substitute for conventional liquid mineral acid. In this work, a novel alkylsulfonic acid functionalized porous aluminoborate molecular sieve (PKU-1) has been prepared through 3-step post-synthetic method, and the high-density acidic sites were tailored and comprehensively characterized by various measurements. These acidity-controllable active sites exhibit high activity and specific regioselectivity towards alcoholysis reaction for the solvent-free production of methoxyl alcohol, and turnover frequency reaches ∼1000 h–1, which is much superior to previous reports. Comprehensive characterizations indicate catalytic centers exclusively come from –SO3H acid sites, rather than other type of Brönsted or Lewis acid sites. A plausible reaction mechanism was proposed to interpret the key role of –SO3H active sites on alcoholysis reaction based on the related experimental results. This work offers a promising solution to generate the controllable acidity and provides an available candidate in the environmentally benign catalysis for selective synthesis of some value-added compounds.

Assessing the lightning performance of sustainable GTL type dielectric liquids versus mineral oils and synthetic ester in a non-uniform electric field

This paper presents for the first time the results of complex comparative tests on the lightning performance of a wide range of sustainable electrical insulating liquids made in GTL (Gas-to-Liquids) technology. Three different GTLs are compared with conventional mineral oils (inhibited and uninhibited) as well as biodegradable synthetic ester. Tests are aimed to determine Lightning Impulse Breakdown Voltage (LIBV) and Acceleration Voltage (Va) at standard lightning impulse voltage of both polarities. Those are performed at 25 mm gap distance of point-sphere electrode setup representing non-uniform electric field distribution. In addition, light emission is studied as well. Results show that for the conditions of experiment LIBV values tend to be similar for all tested dielectric liquids with a slight advantage of mineral oils at negative polarity and GTL-I oil at positive polarity. In turn, in terms of Va, it was found that at negative polarity the GTL oils are, in general, fully comparable with a high grade inhibited mineral oil. The Va of GTLs is in the range 260–275 kV versus 255–260 kV that characterizes mineral oils. When considering positive polarity the GTL-I is slightly inferior to other hydrocarbons with Va equal to 195 kV versus 230–255 kV characterizing other GTLs and mineral oils. For both polarities tested synthetic ester has much lower acceleration voltage in relation to hydrocarbon liquids including GTLs, which constitutes a huge disadvantage of the ester. Although the studies are limited to only one gap distance and non-uniform electric field distribution, it can be stated that the GTLs are worth to be examined as alternative to mineral oil when considering LIBV and Va as the analysed quantities. In addition, a special added value of the performed measurements should be mentioned that the measurements confirmed that Va parameter may be a good dielectric indicator of a dielectric liquid performance, especially when examining new product introduced to the market.

Sources and splitting of special fertilizers application in coffee crop

This study assesses special and mineral fertilizers and the splitting of fertilizer application in coffee - a crop with high nutritional requirements for full yield potential. A 4 × 3 factorial scheme was implemented with four fertilizers [mineral, mineral with polymer, organomineral with cellulosic residue (OM-CR), or sugarcane filter cake (OM-FC)] and three application times, or splits (100% at once, 50%+50%, 33.3%+33.3%+33.3%). Coffee plant height, canopy diameter, plagiotropic branch growth, leaf chlorophyll, nutrient contents in the soil and leaves, and harvest yield after fruit maturation were evaluated in two consecutive crop cycles. The results indicated that organomineral fertilizers performed similarly to other fertilizers regarding coffee leaf chlorophyll and plant height. Only one fertilizer application effectively increased canopy diameter in both crop cycles. In the first crop cycle, OM-FC and conventional mineral fertilizers were significantly better for coffee foliar N content. In contrast, in the second crop cycle, mineral-P, OM-CR, and OM-FC achieved satisfactory results with one fertilizer application, whereas conventional mineral fertilizer required three applications for superior results. There are no differences in leaf P content among different sources and frequencies of application. Still, mineral-P and OM-CR had better soil P content than the conventional mineral fertilizer. OM-CR required two applications to reach high levels of leaf K content, while other fertilizers achieved it with one application. Organomineral and protected mineral fertilizers performed similarly in both crop cycles, with two applications resulting in greater coffee yield in the second cycle, regardless of the fertilizer used.

Quinoa sourdough fermented with Lactiplantibacillus plantarum CRL 1964, a powerful tool to enhance the nutritional features of quinoa snacks.

The remarkable nutritional attributes and potential health advantages of quinoa make it an important candidate for developing innovative ready-to-eat food products. This work aimed to develop a functional ready-to-eat snack based on quinoa sourdough fermented by Lactiplantibacillus (L.) plantarum CRL 1964. Phytate, phosphates, and soluble mineral content (Fe, Mn, Zn, Mg, Ca, and P) were determined in snacks formulated with sourdough and control doughs. An in vitro digestion model was performed on quinoa snacks to assess their mineral bioaccessibility and dialyzability. Phytate content was significantly lower (ca. 42.3%) while phosphates were higher (ca. eightfold) in quinoa-based sourdough and sourdough-based snacks (S1964) than in controls. Soluble minerals were higher (10.2%-32.0%) in S1964 than in controls. Mineral bioaccessibility and mineral dialyzability were also higher (ca. 24.5%) among S1964 and control snacks. The developed quinoa snack made from sourdough fermented by L. plantarum CRL 1964 had less phytate concentration and high bioaccessibility of minerals. These findings underscore the relevance of this innovative technology in creating food products that are not only highly nutritious but also represent a valuable contribution to the market of healthy foods. PRACTICAL APPLICATION: In this study, a novel snack based on quinoa sourdough with improved nutritional properties was developed. The addition of quinoa sourdough fermented by Lactiplantibacillus plantarum CRL 1964 to the preparation of quinoa snacks resulted in a product with a lower concentration of phytate and a higher content of phosphates and minerals (soluble, bioaccessible, and dialyzable). These results underline the efficacy of the new snack as a promising alternative to conventional mineral fortification methods. This innovative approach holds promise for addressing nutritional deficiencies and the demand for healthy snack options in today's market.

Towards cleaner machining: Experimental investigation of collagen-in-water as a novel type of metalworking fluids – A technical feasibility study

Driven by environmental challenges, health concerns and increasing legislative restrictions, a high demand for research regarding alternative metalworking fluids (MWFs) to substitute the conventional mineral oil-containing fluids emerges. In recent years, bio-based fluids have continuously gained attention, as their usage could mitigate the disadvantages of conventionally used fluids, which usually contain mineral oil. Against this background, this research aims to contributing towards biological MWFs by investigating the technical applicability of collagen-in-water fluids through evaluations and comparisons with conventional MWFs. The analyzed bio-based MWF is based on collagen-hydrolysate powder dissolved in water, with collagen acting as a viscosity-increasing additive. The prepared fluids were investigated regarding their viscosity and tribological behavior in cylinder-on-ring experiments as well as tapping-torque tests. Afterwards, first machining experiments were performed for honing and grinding of hardened steel. Force-led cylinder-on-ring experiments show a significant wear reduction, e.g. a value of 13.4 mm2 at 3 wt.% collagen compared to 33.0 mm2 with pure distilled water. Wear further decreased with increasing collagen content. At 3 wt.% and again compared to pure water, tapping torque was reduced by 29 % to 181.7 Ncm, no further torque reduction was observed with increasing collagen concentration. In honing, roughness was reduced using collagen-in-water, however, an 8 wt.% collagen fluid resulted in an 18 % reduction in material removal rate compared to honing oil. In internal grinding, an 8 wt.% collagen fluid achieved an Ra of approximately 0.8 μm, compared to around 0.55 μm with emulsion. The application results demonstrate a high potential for collagen-in-water fluids, however, adjustments are necessary for obtaining competitive fluids.

Environmentally Acceptable Lubricants for Stern Tube Application: Shear Stability and Friction Factor

Stern tube lubricants are essential in maritime operations, safeguarding ship propeller shafts from wear and corrosion while ensuring efficient propulsion. Their role in reducing friction and maintaining system integrity is critical. With growing environmental concerns, the adoption of environmentally acceptable lubricants (EALs) for stern tubes has gained importance, balancing operational performance with environmental protection. This study investigates the rheological and tribological properties of EALs formulated for ship propeller stern tube applications. The primary focus is on comparing these EALs with conventional mineral oils to assess their suitability in marine environments. EALs are increasingly favored due to their biodegradability and reduced environmental impact. Key parameters such as shear stability, friction factor, and temperature dependency were evaluated using a range of experimental methods including rotational viscometry and tribological analysis. The results indicate that the newly formulated EALs based on synthetic esters exhibit the highest viscosity index, a higher range of shear stability, and lower friction factors, compared to commercially available mineral oils, especially under varying operational conditions. These findings contribute to the ongoing efforts to promote eco-friendly lubricants in maritime industries, aligning with global environmental protection initiatives.

Formulation Ratio Effectiveness of Green Metal Working Fluid (GMWF) as a Bio Alternative for Green Manufacturing

Metalworking fluid (MWF) is essential for ensuring quality products and extended tool life during machining operations. While there are various sources of MWF, the need to minimize health hazards associated with mineral-based metal working fluid now calls for more environmentally friendly green metal working fluid (GMWF) from bio-degradable sources. Also, the effectiveness of vegetable-based GMWF significantly depends on the degree of functionalization. Though some studies considered the issue, the comparative analysis of the effect formulations (variation in concentration) of the constituting elements of the GMWF, especially for the base vegetable oil under consideration; has been grossly underreported. In this study, a GMWF emulsion has been developed from soybeans, palm fruits, and coconut with varying formulation ratios. Physicochemical characterization such as flash point, fire point, pour point, pH, density, and viscosity of the developed GMWF were analyzed. Also, a performance evaluation of the said GMWF was carried out and the investigation has shown that the physicochemical properties of the developed GMWF matched, as a potential substitute for conventional mineral-based MWF. Additionally, a performance evaluation conducted during a mechanical machining operation revealed that the GMWF showed an improved surface roughness of about 10.77% compared to conventional mineral MWF. Observations during the machining operation further revealed that the formulated GMWF demonstrated some level of environmental tolerance as it was not associated with misting or the discharge of fumes. The research outcome will impact green machining science and MWF technology for sustainable mechanical machining and cutting fluid development.

Identifying Rare Earth Elements Using a Tripod and Drone-Mounted Hyperspectral Camera: A Case Study of the Mountain Pass Birthday Stock and Sulphide Queen Mine Pit, California

As the 21st century advances, the demand for rare earth elements (REEs) is rising, necessitating more robust exploration methods. Our research group is using hyperspectral remote sensing as a tool for mapping REEs. Unique spectral features of bastnaesite mineral, has proven effective for detection of REE with both spaceborne and airborne data. In our study, we collected hyperspectral data using a Senop hyperspectral camera in field and a SPECIM hyperspectral camera in the laboratory settings. Data gathered from California’s Mountain Pass district revealed bastnaesite-rich zones and provided detailed insights into bastnaesite distribution within rocks. Further analysis identified specific bastnaesite-rich rock grains. Our results indicated higher concentrations of bastnaesite in carbonatite rocks compared to alkaline igneous rocks. Additionally, rocks from the Sulphide Queen mine showed richer bastnaesite concentrations than those from the Birthday shonkinite stock. Results were validated with thin-section studies and geochemical data, confirming the reliability across different hyperspectral data modalities. This study demonstrates the potential of drone-based hyperspectral technology in augmenting conventional mineral mapping methods and aiding the mining industry in making informed decisions about mining REEs efficiently and effectively.