Commercial Grade Research Articles

Mycotransformation of Commercial Grade Cypermethrin Dispersion by Aspergillus terreus PDB-B Strain Isolated from Lake Sediments of Kulamangalam, Madurai.

A fungal isolate Aspergillus terreus PDB-B (accession number: MT774567.1), which could tolerate up to 500 mg/L of cypermethrin, was isolated from the lake sediments of Kulamangalam tropical lake, Madurai, and identified by internal transcribed spacer (ITS) sequencing followed by phylogenetic analysis. The biotransformation potential of the strain was compared with five other strains (A, J, UN2, M1 and SM108) as a consortium, which were tentatively identified as Aspergillus glaucus, Aspergillus niger, Aspergillus flavus, Aspergillus terreus, and Aspergillus flavus, respectively. Batch culture and soil microcosm studies were conducted to explore biotransformation using plate-based enzymatic screening and GC-MS. A mycotransformation pathway was predicted based on a comparative analysis of the transformation products (TPs) obtained. The cytotoxicity assay revealed that the presence of (3-methylphenyl) methanol and isopropyl ether could be relevant to the high rate of lethality.

Effect of dissolved precursors on corrosion characteristics of Ni-based alloy Inconel 625, stainless steel 316L and titanium alloy TA2 in acidic and neutral supercritical water: A comparative study

This work investigated the corrosion characteristics of nickel-based alloy Inconel 625, stainless steel 316L (SS 316L), and commercial grade 2 titanium alloy (TA2) in ZrO(NO3)2-containing and ZrO(NO3)2/KOH-containing supercritical water (SCW) at 400 °C and 25 MPa. During ZrO(NO3)2-containing SCW exposure, Inconel 625 undergoes pitting and intergranular corrosion, while SS 316L and TA2 suffer uniform corrosion. Based on corrosion rate and metal oxide stability, the corrosion resistance follows an order of TA2 > Inconel 625 > SS 316L. The addition of KOH reduces the intergranular corrosion sensitivity of Inconel 625, and leads to different oxide distribution of SS 316L. The thick TiO2 oxide layer mixed with ZrO2 formed in ZrO(NO3)2/KOH-containing SCW enables TA2 to exhibit superior corrosion resistance than Inconel 625 and SS 316L.

Development of alternate process flowsheets to recover an unconventional resource rare earth bearing placer garnet and sillimanite from Southeast Coast of India

ABSTRACT In the present study unconventional resources bearing rare earth mineral garnet and sillimanite have been attempted to recover using different alternate flowsheets. The best commercial grade garnet and sillimanite products are obtained from total heavy mineral concentrate recovered by using a spiral concentrator. The garnet product obtained after cleaning with spiral followed by a magnetic separator has a garnet grade of 98.8%, with a recovery of 97.2% and 4.13% overall yield from the bulk sample containing 4.5% garnet. In case of sillimanite also the spiral material is cleaned with a magnetic separator and followed by flotation yields a sillimanite material containing 98.6% sillimanite grade, with a recovery of 95.3% and an overall yield of 3.9% from most feed sample contain 4.0% sillimanite. Therefore, it is recommended to use gravity to remove the gangue ore before it enters the concentrator and to use magnetic equipment for garnet and flotation to obtain commercial grade sillimanite. Rare earth elements can be recovered from this level of garnet and sillimanite.

Изменение подхода к проектированию горнотехнических систем при открытой разработке месторождений на базе совершенствования принципов управления качеством горной массы

The main effect in transition of deep open pits to the In Pit Crushing and Conveying (IPCC) system of rock mass transportation is achieved through cutting the costs of rock mass hauling. Independence of the transportation system throughput from the haulage distance makes it possible to increase the boundary stripping ratio and extend the service life of the open pit. Transition from the cyclic to the In Pit Crushing and Conveying (IPCC) system of rock mass hauling still leaves insufficiently studied the issues related to assessment of the minimum commercial and cut-off grades of valuable components and contaminants in ores, the permissible thickness of the ore bodies when justifying the feasibility study of conditions, as well as management of the rock mass flow quality, optimization of the rock mass reduction ratio at the stage of its preparation for conveyor hauling from the open pit to the ore stockpiles and, further, to the ore hoppers of the processing plants, and many other challenges. The paper systematizes the results of other research by the authors as well as other data and it shows that the placing the crushing equipment and the belt conveyors within the boundaries of the open pit offers additional opportunities to manage the quality of rock mass flows, i.e. the ore mass and the overburden due to variations in the logistic and hauling schemes of the open pit due to transition to the In Pit Crushing and Conveying (IPCC) system. The above approaches to implementation of the rock mass haulage system in open pits remove the boundaries between mining and processing of minerals, expand the possibilities of targeted formation of technogenic deposits, and potentially expand the range of marketable products of the mining company. In fact, the mining and processing facility is considered as a unified technological process of the complete production cycle carried out in a single technological environment. Implementation of the proposed technological schemes will require changes in the regulatory and legal framework.

Effect of Modified Natural Rubber on the Mechanical and Thermal Properties of Poly(Lactic Acid) and Its Composites with Nanoparticles from Biowaste.

The brittle behavior of poly(lactic acid) (PLA) and PLA composites with inorganic filler limits their applications; the addition of a toughening agent, such as a rubbery phase, was selected to transform the brittle to ductile behavior for versatility in various applications. This work aims to study the properties of PLA and PLA composite with filled nanosized hydroxyapatite (nHA) after adding modified natural rubber (MoNR), which acts as a toughening agent. MoNR refers to poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber. nHA was prepared from fish scales. Its characteristics were investigated and was confirmed to be comparable to those of commercial grade. PLA-MoNR at various MoNR contents and PLA/nHA composites with/without MoNR were prepared by melt mixing. Their morphology, mechanical, and thermal properties were observed and investigated. Samples with MoNR added showed the dispersion of spherical particles, indicating incompatibility. However, the mechanical properties of PLA-MoNR, which had MoNR added at 10 phr, showed toughening behavior (increased impact strength by more than two times compared to that of neat PLA). The PLA/nHA composite with MoNR showed the same result. The addition of MoNR in the composite increased its impact strength by 1.27 times compared to the composite without MoNR. MoNR can be a stress concentrator, resulting in toughened PLA and PLA/nHA composite.

Commercial Grade of P(3HB‐co‐3HHX) Final Properties Adjustment by the Modification of Cooling Conditions in the Injection Molding and Ageing Process

AbstractPoly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) is a polymer obtained by bacterial fermentation that emerges as an alternative to polymers of petrochemical origin. The complex crystallization kinetics that occurs over 15 days after melting, known as ageing, limits its industrial application. During the aging process, there is a change of the degree of crystallinity, which has an effect on the chemical structure of the material. Additionally, changes in the mechanical properties, colorimetry, and dimensional shrinkage are observed. Different material properties are observed depending on the cooling conditions employed. For the ageing process, two different conditions are considered: ageing at room temperature and annealing at high temperature (60 °C).

Morphology evaluation and mechanical properties of oil-resistant thermoplastic vulcanizates comprising carboxylated nitrile butadiene rubber and thermoplastic polyurethane and their comparison with commercial grades

The morphology, the mechanical properties, and the oil-resistance of thermoplastic vulcanizates (TPVs) of carboxylated nitrile butadiene rubber (XNBR) and thermoplastic polyurethane (TPU) were studied & compared with the commercial ethylene-propylene-diene monomer (EPDM)/polypropylene (PP) TPVs from two suppliers. The rubber phase in these new generations of TPVs was cured with an addition-type curative, and no oil & compatibilizer were required to make these TPVs processable. Three XNBR/TPU TPVs were made with different rubber/plastic ratios (15/85, 30/70, and 45/55). The AFM analysis showed that the morphology shifted from a continuous plastic phase to a co-continuous phase with increased rubber content. The rubber domains in these TPVs were not as discrete as reported in the literature for the EPDM/PP TPVs. Still, because of using an addition-type curative, unlike peroxide and resole phenolic resin curatives for the latter, the former TPVs had a significantly better balance of rubber and plastic properties. The oil resistance of these TPVs was 3.5–5 times better than the commercial EPDM/PP TPVs. These promising results show advancement in the TPV world and make these TPVs appealing for hydraulic oil applications.

Dual reconfigurable network from a semi-crystalline functional polyolefin

A statistical copolymer p(E-co-GMA) of ethylene and glycidyle methacrylate (4.5 wt%) is considered as a starting point towards semicrystalline networks with exchangeable links. Application of the binomial law to size exclusion chromatographic data suggests that chains deprived of reactive comonomers would represent less than 6 wt% of the total, allowing to expect the formation of high gel-content networks. Experimentally, up to 98 wt% gel is obtained upon modification with 3,3′-dithiopropionic acid (DTPA). The crosslinking reaction can be performed in the molten state through a 2-steps procedure: 1°) x mol. of a commercial grade p(E-co-GMA), y mol. of DTPA and z mol. of triazabicyclodecene (TBD) are sheared in a twin-screw compounder at 115 °C, a temperature right above the melting point of the polymer precursor, without triggerring the epoxy-acid addition; 2°) the thermolatent reactive blend thereby obtained is then crosslinked at 170 °C. Samples with x = 1, y = 1 to 4 and z = 0 to 0.8 were thus prepared and evaluated. The presence of TBD accelerates disulfide exchange reaction, possibly by involvement of the thiolate anion whereas it decelerates the epoxy-acid addition. The final networks present several characteristic properties of vitrimers such as insolubility in xylene above the melting point, thermo-activated stress relaxation and creep. Particular shape memory regimes, related to the semicrystalline vitrimer character and the high insoluble fraction are demonstrated. Eventually, production scale-up using continuous reactive extrusion is evaluated.

Graphene-containing biocarbon from burlap waste: Property comparison with commercial grade graphene nanoplatelets

In this paper, we report a method for synthesizing high-yield graphene-containing biocarbon from burlap waste through a simple two-step carbonization process. The first step involves feedstock carbonization at 600 °C, followed by ball milling and then graphitization at 1200 °C using KOH. A comparative analysis between the obtained bio-graphene and commercial graphene revealed superior graphene properties of the burlap-based graphene. Notably, this bio-based graphene exhibited exceptional characteristics such as a very high BET surface area in the range of 1021 m²/g, low defect-to-graphene ratio of 0.12 in the Raman spectra, and an overall yield of 19% wt. These findings highlight the potential of burlap waste as a sustainable precursor for high-quality graphene synthesis and its potential for various applications.

Revisit of bake hardening mechanism: Influence of baking on tensile properties of press hardening steels

Paint baking is a process in automotive industries to accelerate the curing of paint and increase yield strength of steel panel for improving the dent resistance due to the formation of well-known Cottrell's atmosphere. However, our careful study on bake hardening mechanism of three press hardening steels (PHS) indicates a different explanation. We developed two novel Nb/Si alloyed steels with superior tensile properties when compared with the commercial grade of 22MnB5. It was found that the paint baking at 170 °C led to the significant increase of yield strength but the decreases of both uniform and total elongation for all the three PHSs. According to the neutron diffraction results, both the baking and the tensile straining until the elastic-plastic transition strain (εep) led to the decrease of full width at half maximum (FWHM), indicating that both should release the residual stress (RS) that was generated during martensite transformation; whilst the internal friction examinations reveal no presence of Snoke peak and no influence of the baking on Snoek-Kê-Köster peak. Based on these results, the kinetics simulation on forming Cottrell's atmosphere and the relevant microstructural characterization results, we can safely conclude that the strengthening caused by the baking is not ascribed to the change of Cottrell atmosphere, carbide precipitates or retained austenite (RA) grains during the baking although commonly believed, but just due to the release of RS. Moreover, the relaxation of compressive RS in martensite and the transformation of RA grains to martensite are the main contributor to the strain hardening of invented PHSs before εep. Therefore, the baking treatment decreases both strain hardening capability and ductility of studied PHSs due to the release of the RS.

Upgrading of Pyrolytic Char Generated from Waste Tyre Pyrolysis for Solid Tyre Industry

In Sri Lanka, accumulation of tons of low-quality pyrolytic char (PT-char) in pyrolysis plants is a significant issue in waste tyre management. Finding a solution to upgrade low-quality PT-char is urgent in Sri Lankan context as it initiates a method of finding a solution to the disposal issue of PT-char. As a result, the current study introduces an efficient and cost-effective routine for upgrading low grade PT-char into value-added products which is not being successful before. The upgrading method entails carefully regulating size reduction of the low-grade PT-char (particle size<50 μm) and following optimization of acid-base demineralization parameters. After the size reduction of PT–char, demineralization procedure was introduced using low char: acid/base ratios (1:2), diluted acids and bases (2 M HCl and 2 M NaOH), low temperatures (30 0C-60 0C), and short reaction times (30-60 minutes). Purity and surface characteristics of upgraded char were investigated using XRD, elemental analysis, SEM, and TGA. Based on a CHN analysis, 67% (w/w) of initial carbon content of crude C-PT char was increased up to 91% (w/w) by washing it twice with 2 M HCl and once with 2 M NaOH (2 M H2+2 M S) while reducing ash content from 17.65% (w/w) to 3.59% (w/w). Significance removal of metals such as Zn (1.14% w/w) , Fe (0.34% w/w), Mg (0.25% w/w) and Ca (2.71% w/w) from C-PT char were observed after treating with 2 M H2+2M S (Zn 0.36%w/w , Fe 0.06%w/w, Mg 0.01%w/w and Ca 0.01% w/w). Removal of Zn from C-PT char further confirmed by XRD and surface modification was confirmed by SEM images. Additionally, the rheological and physico-mechanical properties of the upgraded char incorporated solid tyre base compounds were evaluated and compared with commercial grades of carbon black; N 330, and N 660. It was observed that tensile strength, tear strength, hardness and compression properties of purified PT-char incorporated rubber compounds were not significantly different and exhibit resemble properties to the samples prepared using commercial carbon black grades. Overall, it can be confirmed that upgraded PT char has a significant potential to be used as an economical alternative for reinforcement filler in solid tyre industry and upgrading procedure is efficient and economically viable than the conventional methods. 
 Keywords: Pyrolytic char, Demineralization, Purification, Modification

Enhancing wood functionality: A novel approach with Al2O3 impregnated paper on densified wood surface

To improve the surface properties of low-density wood, poplar wood was functionalized by laminating Al2O3 impregnated paper onto poplar wood (Populus tomentosa Carr.) via unilateral surface compression. Bonding strength between Al2O3 impregnated paper and wood reached up to 3.08 MPa, meeting commercial grade I requirements for impregnated paper laminated wood flooring. A cross-linked structure between Al2O3 impregnated paper and wood was formed without visible cracks or other defects. Density of the functionalized wood surface increased remarkably and the surface hardness was significantly improved, surpassing that of hardwoods for wood flooring. The functionalized wood surface also exhibited high wear resistance, which reached to the specification for commercial grade I impregnated paper laminated wood flooring. Additionally, the water resistance of the functionalized wood surface was significantly improved through lamination with Al2O3 impregnated paper. The functionalized wood demonstrated high applicability for wood flooring.

Tracking Sodium Cluster Dynamics in Hard Carbon with a Low Specific Surface Area for Sodium‐Ion Batteries

AbstractHere, the sodium storage mechanism in commercial grade hard carbon with a low surface area is comprehensively investigated using electrochemical impedance spectroscopy (EIS), the galvanostatic intermittent titration technique, and in situ Raman spectroscopy for fresh and cycled electrodes. The reversible shift of the carbon G‐band peak on Raman spectra and substantial change of the charge‐transfer resistance in the sloping region of the voltage profile indicates the intercalation of sodium ions into hard carbon, whereas the low‐voltage plateau is associated with the pore‐filling process. In situ Raman analysis at low frequencies reveals that the pore filling is progressed via formation of small sodium clusters in closed pores. Prolonged cycling demonstrates that intercalation is stable and consistent throughout multiple charge–discharge cycles. The transition from intercalation to pore filling strongly affects the diffusion behavior, leading to considerably slower diffusivity at low voltage. The EIS effectively differentiates the contribution of adsorption to charge storage. The gradual growth of the solid‐electrolyte interphase layer affects the rise of the interfacial resistance as cycling progresses. In combination with the slower diffusivity, the low‐voltage plateau region strictly impedes fast de/sodiation and eventually causes capacity fade.

Simulation analysis and experimental testing of the grading performance of small potato grading device

AbstractExisting potato grading device has a complex structure and a large volume, which is not suitable for small‐scale potato farmers. However, traditional manual grading methods not only have low efficiency but also high labor costs. This article developed a small movable rotating plate (MRP)‐type potato grading device, and the influences of three factors (the height of the horizontal slide, the tilt angle of the inclined slide, and the chain speed) on the grading efficiency and accuracy were investigated using the discrete element method and virtual orthogonal experiments. It was found that the horizontal slide height of 185 mm, the inclined slide tilt angle of 3.5°, and the chain speed of 0.9 m/s yielded the optimal grading efficiency (13.84 t/h) and grading accuracy (94.11%). Finally, the potato grading process was tested and validated through indoor tests, and the optimal grading accuracy was 91.04%. The grading accuracy deviation between the test and simulation results was less than 8%.Practical ApplicationCurrently, most commercial potato grading machines are designed for large‐scale farms, which are not suitable for developing countries. The potato grading device designed in this article can not only be used independently by small‐scale farms, but also be integrated with potato combine harvesters to achieve potato harvest and grading joint operations. This grading device has a simple structure, small footprint (1700 × 1200 × 840 mm3), and a very low cost ($600). With a high grading efficiency and accuracy, it can significantly improve the grading productivity of small and medium‐sized potato farmers in developing countries, reduce the production costs, and save labors.

Validation of low-cost reflectometer to identify phytochemical accumulation in food crops

Diets consisting of greater quantity/diversity of phytochemicals are correlated with reduced risk of disease. This understanding guides policy development increasing awareness of the importance of consuming fruits, grains, and vegetables. Enacted policies presume uniform concentrations of phytochemicals across crop varieties regardless of production/harvesting methods. A growing body of research suggests that concentrations of phytochemicals can fluctuate within crop varieties. Improved awareness of how cropping practices influence phytochemical concentrations are required, guiding policy development improving human health. Reliable, inexpensive laboratory equipment represents one of several barriers limiting further study of the complex interactions influencing crop phytochemical accumulation. Addressing this limitation our study validated the capacity of a low-cost Reflectometer ($500) to measure phytochemical content in selected crops, against a commercial grade laboratory spectrophotometer. Our correlation results ranged from r2 = 0.81 for protein in wheat and oats to r2 = 0.99 for polyphenol content in lettuce in both the Reflectometer and laboratory spectrophotometer assessment, suggesting the Reflectometer provides an accurate accounting of phytochemical content within evaluated crops. Repeatability evaluation demonstrated good reproducibility of the Reflectometer to assess crop phytochemical content. Additionally, we confirmed large variation in phytochemical content within specific crop varieties, suggesting that cultivar is but one of multiple drivers of phytochemical accumulation. Our findings indicate dramatic nutrient variations could exist across the food supply, a point whose implications are not well understood. Future studies should investigate the interactions between crop phytochemical accumulation and farm management practices that influence specific soil characteristics.

Optimization of Growth Conditions for Chlorpyrifos-Degrading Bacteria in Farm Soils in Nakuru County, Kenya.

Chlorpyrifos (CP) is a chlorinated organophosphate pesticide. In Kenya, it is commonly used as an acaricide, particularly in dairy farming, leading to soil and water contamination. The study is aimed at isolating bacteria with CP-degrading potential and optimizing their growth conditions, including temperature, pH, and CP concentration. The enrichment culture technique was used, with minimal salt medium (MSM) supplemented with commercial grade CP. A multilevel factorial design was used to investigate the interactions of temperature, pH, and CP concentration. According to the findings, seven bacterial strains with potential to degrade CP were characterized and identified as Alcaligenes faecalis, Bacillus weihenstephanensis, Bacillus toyonensis, Alcaligenes sp. strain SCAU23, Pseudomonas sp. strain PB845W, Brevundimonas diminuta, and uncultured bacterium clone 99. Growth and biodegradation of bacteria differed significantly among the isolates across pH value, temperature, and concentrations (P ≤ 0.05). The optimum conditions for growth were pH 7, temperature of 25°C, and 25mg/l chlorpyrifos concentration, while optimum degradation conditions were pH 5, temp 25°C, and CP conc. 25mg/l. The Pearson correlation between optimum growth and degradation showed a weak positive relationship (R = 0.1144) for pH and strong positive relationship for temperature and concentration of chlorpyrifos. Other than pH, the study shows that there could be other cofactors facilitating the chlorpyrifos degradation process. The findings show that an efficient consortium, at 25°C and pH 5, can include Bacillus toyonensis 20SBZ2B and Alcaligenes sp. SCAU23 as they showed high optical density (OD) values under these conditions. These results indicate the potential for these bacteria to be employed in chlorpyrifos-contaminated ecosystem detoxification efforts upon manipulation of natural growth conditions. The findings of this study offer a potential foundation for future research into the reconstitution of a consortium. Based on the optimum conditions identified, the isolated bacterial strains could be further developed into a consortium to effectively degrade CP in both laboratory and field conditions. Dairy farmers can utilize the isolated strains and the consortia to decontaminate farm soils.

Designing of novel microstructure and its impact on the improved service temperature mechanical performance of 2nd and 3rd generation advanced intermetallic TiAl alloys

Advanced lightweight TiAl based intermetallic systems, capable of surviving elevated temperatures, have been a topic of interest, considering their ever-increasing demands in aerospace industries. The optimization of solidification and processing methods stands as a pivotal factor in microstructural engineering for TiAl systems, aiming to attain desired mechanical properties. The present study focuses on two distinct alloy systems, a commercial grade 2nd generation, i.e., Ti–48Al–2Cr–2Nb (at. %), and a newly developed 3rd generation, i.e., Ti–45Al–2Cr-7.5Nb-0.2B (at. %) alloys. Interestingly, the variation in the solidification path, triggered by higher Nb content along with a minor amount of B, accounts for the substantial microstructural refinement for the 3rd generation TiAl alloy. Nevertheless, prominent segregation of Nb and Cr to the β0 phase is observed in both the as-cast microstructure, which restricts the applicability of the alloys. Remarkably, a novel bilamellar-biglobular (BLBG) microstructure consisting of γ and α2 phases in both lamellar and globular morphologies is achieved through heat treatment for both categories of alloy. Elevated temperature tensile testing depicts an exceptional strength-ductility combination for 3rd generation BLBG microstructure. Excellent twin-twin activity and twin-induced plasticity effect are observed to govern the deformation mechanism. Overall, the path of solidification, phase distribution, and its effect on the deformation mechanism are thoroughly analyzed, which is of particular interest from a design and application point of view.

Anti-platelet aggregation activities of different grades of Angelica sinensis and their therapeutic mechanisms in rats with blood deficiency: insights from metabolomics and lipidomics analyses.

In traditional Chinese medicine, the radix of Angelica sinensis (Oliv.) Diels (RAS) is mainly used to replenish and invigorate the blood circulation. This study investigated anti-platelet aggregation activities were used by New Zealand rabbits, and high-performance liquid chromatography data were obtained to determine the spectrum-effect relationship for different commercial grades of RAS. Plasma and urine metabolites were examined using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry-based metabolomics to elucidate the mechanisms underlying the role of these metabolites in a rat model of blood deficiency (BD). Plasma and spleen metabolites were additionally examined using ultra-performance liquid chromatography plus Q-Exactive tandem mass spectrometry-based lipidomics to clarify the mechanisms of RAS in treating BD. The third grade of RAS exhibited the best activity in replenishing and invigorating blood in vitro and in vivo. Ferulic acid, ligustilide, senkyunolide I, uridine, and guanine are quality markers of anti-platelet aggregation activity. Based on the metabolomics results, 19 potential biomarkers were screened in plasma, and 12 potential metabolites were detected in urine. In lipidomics analyses, 73 potential biomarkers were screened in plasma, and 112 potential biomarkers were screened in the spleen. RAS may restore lipid metabolism by regulating disorders of glycerophospholipid and sphingolipid metabolism, the tricarboxylic acid cycle, amino acid metabolism (thereby improving energy metabolism), and arachidonic acid metabolism (thereby promoting blood circulation). These results provide a deeper understanding of the effects of different grades of RAS and a scientific reference for the establishment of grading standards and for the clinical use of RAS.

Petrographic, Petrophysical, and Mechanical Characterisation of the Ultra- Tight Casa Cruz Sandstone, Moruga Formation, Southern Basin, Trinidad

Durability, compactness, and natural strength of sandstones are pivotal properties for its subsequent application as a building material. If a sandstone is tight and contains petroleum, then hydraulic fracturing is necessary to achieve commercial production. The Casa Cruz Sandstone Member, southern Trinidad, is currently being explored as a potential petroleum target and building material. This study investigates the petrographic, petrophysical, and mechanical characteristics of the Casa Cruz sandstone to understand the factors that control the quality of the sandstone and to determine the sandstone’s suitability as a natural resource. A thin-section analysis was performed to investigate the mineralogy, texture, and diagenesis of the sandstone. Permeability, porosity, density, P- and S-wave velocities, unconfined compressive strength (UCS) and confined compressive strength were measured. The elastic properties (Young’s modulus, shear modulus, bulk modulus, and Poisson’s ratio) were estimated from inversion of the P- and S-wave velocities. The results show that the Casa Cruz sandstone is one of the tightest sandstone types reported in the literature with porosity of 0.7% and permeability of 4.7 x 10-22 m2 (0.47 nD). Authigenic cementation and mechanical compaction are the main diagenetic processes that jointly controlled the quality of the sandstone. The sandstone was classified as a very strong (UCS of 128 MPa) quartz-arenite and is barren of petroleum and bioclasts. Brittle failure behaviour was exhibited, accompanied by axial splitting fractures and shear fractures under unconfined and confined conditions, respectively. The Casa Cruz sandstone is suggested to be an excellent building material as its petrophysical and mechanical properties are comparable to those of commercial industry grade of Westerly granite and Naparima Hill argillite.

Ready-to-use graphene-related material-added multi-grade oils: characterization and performance in car engine working conditions.

The need for energy efficiency is leading to the growing use of additives to enhance the performance of oil in automotive engines. Great interest is focused on nano-additives even if to date there is still no practical use in commercial liquid lubricants. Herein, the potential of industrially scalable and low-cost graphene-related materials (GRMs) as additives to enhance the performance of oil in automotive engines is explored. The use of polyalkylmethacrylate dispersants, the most common key additives to formulate "green technology" lubricant oils liquid-processed GRM, is explored, investigating the role of the lateral size and the chemical analysis in the stability of the lubricant GRM dispersions. Showing the maximum duration of stability and a production method that avoids the use of strong oxidants, rheological tests were then focused on multilayered graphene flakes with sub-micrometre lateral size mixed in two commercial oil grades (5W-30 and 5W-40) under conditions similar to those of engine operation. The addition of such a filler increases the viscosity without affecting the Newtonian fluid behavior, while four-ball tests show a reduction in wear, indicating improved lubrication performance. Finally, preliminary bench-test on a commercial car engine showed increased power output corresponding to enhanced engine efficiency. The results clearly indicate the effective improvement in lubricating commercial oils due to GRM additives.