Search Results (619)

The reuse of industrial residues has gained importance due to environmental and public health concerns associated with improper waste disposal. Steel scale (CDA), a by-product of machining and rolling operations, represents a residue with technological potential for incorporation into polymer composites. This study developed a low-cost and sustainable material by reinforcing an orthophthalic polyester matrix with CDA and systematically evaluated its mechanical, thermal, and structural properties. Four formulations were prepared based on the maximum feasible filler loading: R (pure resin), C1 (50% CDA), C2 (100% CDA), and C3 (150% CDA). Composites were manufactured by cold-press molding under a two-ton compressive load. Characterization included tensile, flexural, and impact testing, thermogravimetric analysis (TGA), thermal conductivity, apparent density, liquid absorption, and morphological assessment by scanning electron microscopy (SEM). CDA incorporation reduced tensile and flexural strength but increased elastic modulus, impact toughness, and thermal conductivity. The C3 composite exhibited the highest thermal stability, retaining more than 50% of its initial mass at 500 °C. Density and liquid absorption increased proportionally with filler loading, and SEM revealed heterogeneous microstructures with particle agglomeration, sedimentation, and interfacial gaps, explaining the mechanical and thermal trends. The findings demonstrate the feasibility of producing dense and low-cost polyester composites reinforced with steel scale. The structure–property relationships identified in this study establish a foundation for subsequent investigations focusing on additional functional behaviors of this waste-derived material system. Full article

Cold-pressed rapeseed oil aligns well with the trend of growing demand for minimally processed, health-promoting food products. It is essential to identify suitable storage conditions that protect cold-pressed rapeseed oil from oxidation, thereby extending its shelf life. In this study, the effect of gelatin/polyvinyl alcohol film strips enriched with ethyl sinapate (GPE) and immersed in cold-pressed rapeseed oil samples was evaluated during an accelerated storage test (14 days at 40 ± 1 °C under light (power of luminous flux = 385 lm). The influence of bottle type differing in shape (Marasca and Dorica) and glass colour (amber and clear) was also assessed. The incorporation of GPE into the stored oils enhanced their antioxidant activity (AA) determined by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS = 1956.78–2334.10 µmol Trolox (TE)/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH = 528.29–691.19 µmol TE/100 g), ferric reducing antioxidant power methods (FRAP = 454.14–511.61 µmol TE/100 g) and total phenolic content (TPC = 41.62–47.25 mg sinapic acid (SA)/100 g) compared to oils without film strips (ABTS = 1217.89 –1422.80 µmol TE/100 g, DPPH = 376.85–464.13 µmol TE/100 g, FRAP = 98.28–126.40 µmol TE/100 g and TPC = 6.38–8.02 mg SA/100 g) after first week of storage and confirmed the effective gradual release of ethyl sinapate from films to oils during two weeks of accelerated storage (ABTS = 2064.80–3086.47 µmol TE/100 g, DPPH = 597.11–854.37 µmol TE/100 g, FRAP =428.00–599.76 µmol TE/100 g, and TPC = 35.02–57.19 mg SA/100 g). Moreover, the GPE inhibited oil deterioration by reducing both primary (peroxide value (PV) = 3.75–5.11 meq O₂/kg and 3.64–4.89 meq O₂/kg, K₂₃₂ = 1.236–1.494 and 1.551–1.675 after the first and second week of storage, respectively) and secondary oxidation products (anisidine value (pAnV) = 1.03–1.16 and 1.08–1.61; K₂₆₈ = 0.102–0.170 and 0.185–0.237 after the first and second week of storage, respectively) compared to oxidative status of oils without film strips (PV = 3.76–5.59 meq O₂/kg, K₂₃₂ = 1.452–1.828, pAnV = 0.85–2.27, K₂₆₈ = 0.154–0.263). In addition, synchronous fluorescence spectroscopy was applied to monitor changes in the main fluorescent components of the studied oils. Overall, the use of a dark glass bottle combined with antioxidant film strips proved to be an effective strategy for prolonging the shelf life of cold-pressed rapeseed oil. Full article

Carbon nanocomposites have gained interest due to the rapid development of nanotechnology. The graphite-based composites have been demonstrated to possess unique mechanical, electrical, and thermal properties. This paper presents a facile one-step sonochemical synthesis of antimony sulfoiodide (SbSI)/graphite nanocomposite. The weight concentrations of graphite in the prepared material varied from 0% to 33.3%. The morphology and chemical composition of the SbSI/graphite nanocomposites are studied with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. SEM examination shows that SbSI/graphite nanocomposite consists of one-dimensional SbSI nanostructures and graphite microparticles. The influence of graphite concentration on the energy band gap of SbSI/graphite nanocomposite is investigated using diffuse reflectance spectroscopy (DRS). The prepared materials are cold-pressed to obtain the bulk samples. They are characterized by direct current (DC) electrical measurements and thermoelectric examination. The increase in the graphite concentration in the SbSI/graphite nanocomposite resulted in a significant reduction in the electrical resistivity of the material. The Seebeck coefficients of the pristine SbSI nanowires and SbSI/graphite nanocomposite are determined for the first time. The investigations of the thermoelectric effect reveal that these nanomaterials exhibited p-type electrical conductivity. The thermoelectric power factor of the SbSI/graphite nanocomposite is examined as a function of the graphite concentration. The presented work demonstrates the comprehensive optical, electrical, and thermoelectric characterization of novel hybrid SbSI/graphite nanocomposites, which has not been studied before. Full article

The evolving landscape of the liquid fuels market, together with changing legal regulations, has prompted consideration of using artificial intelligence methods for the physicochemical analysis of fuel and biofuel blends. The objective of the study was to determine the dynamic viscosity of diesel fuel and its blends with vegetable oils derived from rapeseed, camelina, flax, and mustard. These oils were selected due to their previous applications in the petrochemical industry. The oils used in the study were obtained by cold pressing with a screw press. The measurements were performed over a temperature range of 5 to 85 °C at mass ratios containing 20%, 40%, 60%, and 80% vegetable oil in diesel fuel. A Brookfield-type rotational viscometer was employed for the measurements. Based on the resulting laboratory data, mathematical models of dynamic viscosity were developed. Furthermore, the experimental results were used to train a neural network to analyse relationships among dynamic viscosity, temperature, and vegetable oil content in the blend. Both the empirical (mathematical) models and the models describing changes in dynamic viscosity as a function of temperature and component content in the vegetable oil–diesel blends achieved coefficients of determination (R²) exceeding 0.99. Full article

Waste from the fat-processing industry represents a challenging stream due to its physicochemical properties and environmental impact. Valorization through recovery and reuse offers ecological, economic, and social benefits. This study focused on mushy lipid residues generated during cold pressing of oilseeds (sunflower, flax, blue poppy, hemp, black cumin, and walnut) and evaluated their potential for lactone biosynthesis. The waste was analyzed for protein and fat content, while fatty acid profile, acid and peroxide values, oxidation stability, and health-related indices characterized the extracted oils. Polyphenol content and antioxidant activity of the residues were also determined. Subsequently, the waste was used as a substrate in biotransformation processes with Lactiplantibacillus plantarum and Yarrowia lipolytica. The results showed high protein (13.1–19.4%) and fat levels (65.0–77.3%) across all residues. The lipid fractions were rich in monounsaturated and polyunsaturated fatty acids, comprising nearly 90% of the total fatty acids, with oleic and linoleic acids being the dominant components. These features highlight their strong valorization potential, particularly for the microbial synthesis of aroma-active lactones. Under the applied conditions, the production of γ-dodecalactone and δ-decalactone reached 0.76 g/L and 1.62 g/L, respectively, confirming the suitability of cold-press residues as substrates for sustainable biotechnological applications. Full article

This study aimed to evaluate the effects of different pretreatment methods on the yield and chemical composition of Nigella sativa L. (i.e., black cumin) cold-pressed oil. Different pretreatment methods used included convection heating, microwave, ultrasound and pulsed electric fields (i.e., PEF); we investigated their effects on key parameters, including oil yield, fatty acid composition, total phenol and flavonoid content, peroxide value, acidity and antioxidant activity. However, no single pretreatment method was found to be better than all others. Instead, ultrasonication and pulsed electric fields (PEF) showed significant advantages. Ultrasonication showed the highest total phenolic content and improved oxidative stability, while PEF improved flavonoid content and antioxidant activity. Therefore, these findings suggest that a combination of several pretreatment options should be considered depending on specific industrial goals related to quality improvement and sustainability. This research also contributes to the existing knowledge on Nigella sativa L. oil processing and provides additional insights for optimizing extraction technique. Full article

This work presents the development and characterization of laminated composite panels produced from açaí residues and fibers, incorporated into a castor oil-based vegetable polyurethane matrix. The study aimed to evaluate the potential of these Amazonian agro-industrial residues as lignocellulosic reinforcement in sustainable materials. The manufacturing process was carried out by manual lamination and cold pressing, following the recommendations of ABNT NBR 14810-2:2018. The physical (moisture, density, and swelling) and mechanical (perpendicular tensile and static flexural) properties of the resulting panels were analyzed. The results revealed an average moisture content of 6.23% and a 24 h swelling of 2.76%, which are values within and well below the regulatory limits, respectively. The perpendicular tensile strength (0.49 N/mm²) exceeded the minimum required value, indicating good interfacial adhesion and internal cohesion. However, the flexural strength and modulus of elasticity (2.4 N/mm² and 1323 N/mm²) were below the standards due to the absence of oriented fibers and density heterogeneity. It is concluded that the composite has high potential for indoor applications with low structural stress, standing out for its lightness, dimensional stability and environmental viability in the use of açaí residues. Full article

Cold pressing is a sustainable oil extraction method that operates without chemical solvents, requires relatively low energy input, and preserves bioactive compounds, making it a recognized green technology in line with circular economy principles. By enabling full utilization of raw materials and valorization of by-products, it supports resource efficiency, waste reduction, and the development of bio-based products. This study provides the first comprehensive mapping of Serbia’s small-scale cold-pressed oil producers, based on data from the Central Register of Food Business Operators, local inspectorates, agricultural fairs, and social media, classified according to NUTS 2024 statistical regions. A total of 55 producers were identified, with over 60% operating as artisanal units (≤15 t/year), typically using screw presses of 20–50 kg/h capacity. Pumpkin seed was the most common raw material (30 producers), followed by sesame (21), hazelnut (20), sunflower (19), and flaxseed (19), while niche oils such as jojoba, argan, and rosehip were produced on a smaller scale. Medium and large facilities (>15 t/year) were concentrated in Vojvodina and central Serbia, focusing on high-volume seeds like sunflower and soybean. Integration of green screw press technologies, zero-kilometer supply chains, and press cake valorization positions this sector as a driver of rural development, biodiversity preservation, and environmental sustainability, providing a strong basis for targeted policy support and process optimization. Full article

In this paper, we report the effects of cold rolling, ball milling, and cold pressing on the first hydrogenation behavior of Ti_0.488Fe_0.460Mn_0.052 alloy synthesized by gas atomization and exposed to the air for an extended period. It was found that cold pressing led to a higher hydrogen absorption capacity of 1.9 wt.%, while ball milling significantly improved the kinetics, achieving an incubation time of only 7 min. The cold-rolled sample (5 passes) showed a hydrogen absorption capacity similar to the ball-milled sample (1.5 wt.%) but with a slower hydrogenation rate. To further optimize the cold rolling process, the influence of the rolling atmosphere and the number of passes was systematically examined. In both air and argon, increasing the number of cold rolling passes resulted in longer incubation times. However, samples rolled under argon showed shorter incubation times compared to those rolled in the air. The difference between the two atmospheres became more pronounced after 20 rolling passes; the sample rolled in argon showed an incubation time of 55 min, whereas the sample rolled in air failed to absorb hydrogen even after 24 h. Full article

Cold-pressed chia oil (Salvia hispanica L.) is highly susceptible to oxidative deterioration due to its exceptional α-linolenic acid content. This study evaluated the effect of increasing α-tocopherol concentrations (0–0.10% w/w) on its oxidative stability through accelerated oxidation testing (Oxitest) and long-term refrigerated storage. α-Tocopherol was selected because it is a widely accepted antioxidant in edible oils according to the Codex Alimentarius and FAO/WHO guidelines. A randomized block design (n = 3 independent extraction batches) was used to determine the induction period (IP) at 80 °C, followed by a 15-month evaluation at 15 °C of the control and the most promising treatment. α-Tocopherol increased oxidative resistance in a dose-dependent manner, but concentrations above 0.05% offered no additional benefits. The 0.05% treatment significantly prolonged the IP and effectively limited increases in peroxide and acidity values, keeping all parameters within Ecuadorian regulatory limits and consistent with international quality standards. Fatty-acid profiling confirmed that this antioxidant level slowed α-linolenic acid degradation, preserving the PUFA-rich profile of chia oil. These findings show that low-level α-tocopherol supplementation is a practical strategy to improve long-term stability of cold-pressed chia oil without altering its nutritional properties, providing valuable evidence for the formulation and commercialization of premium functional oils. Full article

Horseradish (Armoracia rusticana L.) root (HRP) and leaf (HLP) pomaces, by-products of juice production by cold-pressing, were analyzed as a novel potential source of natural antioxidants. Chromatography analysis (UHPLC Q-ToF MS) of the bioactive compounds of pomaces was performed along with spectrophotometric determination of total phenolic content (TPC), total flavonoid content (TFC), total phenolic acid (hydroxycinnamic) content (TPAC), and antioxidant capacity (via 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic-acid) (ABTS^•+) radicals’ scavenging activity and ferric reducing antioxidant power (FRAP)). The concentrations of TPC, TFC, and TPAC differed among the pomaces, significantly favoring HLP. However, both horseradish pomaces (HRP and HLP) contained a considerable amount of various phenolics, with kaempferol and its glucosides dominating. In addition, they exhibit pronounced antioxidant activity, which is confirmed by all three methods used (DPPH, ABTS, and FRAP). These results highlight the potential of valorizing horseradish processing waste as a natural, reliable source of health-promoting bioactive compounds and functional ingredients in food products, thereby fortifying food, preventing oxidation, and prolonging shelf-life. In addition, this study supports endeavors to reduce food waste by providing new insights into the valorization of horseradish pomace, thus contributing to sustainable development and environmental protection. Full article

In the Yucatán Peninsula, Citrus aurantium L. has a strong cultural and culinary relevance where local industries already process its juice and essential oils, producing large amounts of by-products. In this context, green chemistry strategies have accelerated the valorization of agro-industrial residues, where Natural Deep Eutectic Solvents (NADESs) stand out due to their low cost, ease of preparation, and high extraction efficiency. This study focuses on evaluating different NADES combinations for the extraction of bioactive compounds from C. aurantium by-products, obtained after essential oil (cold pressing) and juice (mechanical pressing) extraction. A 3 × 2 × 2 factorial design was implemented to evaluate the effect of hydrogen bond donor (HBD: fructose, glucose and glycerol), molar ratio (MR: 1:1 and 1:2 mol/mol choline chloride (ChCl:HBD)) and added water (AW: 50 and 70%) on the polyphenolic profile, total phenolic content, total flavonoid content, ascorbic acid content and antioxidant capacity. HBD was the most critical factor in the extraction of bioactive compounds; the extract obtained with glycerol and 70% AW exhibited the highest hesperidin content (2186.08 mg/100 g dry mass), while the same HBD with 50% AW exhibited the highest quercetin + luteolin extraction (721.32 mg/100 g dry mass), both at the same MR (1:1 mol/mol). Glycerol also achieved the highest recovery of total flavonoids (1829.7 ± 17.85 mg quercetin equivalent/100 g dry mass) with an MR of 1:2 mol/mol and 70% AW. Finally, all other maximum values were obtained with fructose-based NADESs: the highest total phenolic content (3603. 7 ± 52.9 mg gallic acid equivalent/100 g dry mass) was achieved at an MR of 1:1 mol/mol and 50% AW, while for both vitamin C (1964.8 ± 33.7 mg ascorbic acid equivalent/100 g dry mass) and antioxidant capacity (84.31% inhibition), the maximum was reached at an MR of 1:2 mol/mol and 50% AW. Full article

The objective of this study was to determine the moisture content gradient over the thickness of glued laminated timber structures, manufactured as five-layer structures from two different species. Beech (Fagus sylvatica L.) or oak (Quercus robur L.) were used for the faces, and fir (Abies alba Mill.) or lime (Tilia cordata L.) were used for the core layers. Thus, four types of mixed glulam structures resulted. The layers were glued with a polyurethane adhesive for outdoor uses, and then cold-pressed. Samples were also prepared from each individual species as control specimens. All samples were exposed to two types of climate conditions, having cyclic and constant parameters. The first climate test involved cyclic variation in temperature and relative air humidity: 30 °C/40%/12 h, alternating with 10 °C/80%/12 h. The second climate test involved constant exposure conditions, but with higher humidity over a longer period: 15 °C/90%/3 weeks. The moisture content gradient between the layers of the structure was determined and correlated to the delamination effect, assessed by visual analysis. Based on the findings in this work, the lowest values of the moisture gradient were determined for the oak–fir mixed structures, resulting in the total absence of delamination and cracks between the outer oak layers and the inner fir layers. Full article

The present study explores the production of metallized titanomagnetite briquettes, with a view to addressing two key issues. Firstly, it seeks to address the growing shortage of high-quality iron-bearing raw materials. Secondly, it looks at how to meet the increasingly stringent environmental constraints. The conventional blast-furnace treatment of titanomagnetite is hindered by the formation of refractory Ti-rich slags. It is hereby proposed that a single-cycle briquetting process in conjunction with a thermal reduction route should be utilized. This approach enables precise regulation of the Fe/flux ratio. Experiments were conducted on a low-grade titanomagnetite concentrate (68.5% Fe) from the Pervouralsk deposit (Russia). Cylindrical briquettes (D 15–20 mm, h 8–10 mm) were subjected to a pressure of 300 MPa during the pressing process, with the utilization of diverse binders comprising rubber cement, CaO, graphite + water, and basic oxygen-furnace (BOF) slag + sodium silicate. Following an oxidative pre-heating process at 1300 °C for two hours, followed by a gas-based reduction process at 1050 °C for three hours, with a CO/N₂ ratio of 90/10, the products demonstrated an oxidation rate of 85–95% and a cold compression strength of 16–80 MPa. The highest observed strength (80 MPa) was obtained with a binder comprising CaO·MgO·2SiO₂ (diopside/merwinite), which forms a low-viscosity melt, fills 90% of pores and crystallizes as acicular Mg-SFCA-I during cooling. Conversely, the CaO·TiO₂ and FeO·TiO₂ + Fe₃C associations yield brittle structures and a maximum strength of 16 MPa. The optimum briquette (0.55% CaO, D/H = 20/10 mm) exhibited a 95.7% metallization degree, a compressive strength of 48.9 MPa, and dimensional changes within acceptable limits, thus fulfilling the requirements for electric arc furnace feedstock. Further research is required in the form of a full Life Cycle Assessment and pilot-scale testing. However, the results obtained thus far confirm that titanomagnetite briquettes with a binder consisting of CaO, MgO and SiO₂ are a promising alternative to pellets for low-carbon steelmaking. Full article

Snow construction plays a crucial role in military operations in cold regions, providing tactical fortifications, thermal insulation, and emergency infrastructure in environments where conventional building materials are scarce or require extensive infrastructure for support. Current snow construction methods, including manual piling and compaction, are labor-intensive and inconsistent, limiting their use in large-scale or time-sensitive operations. This study explores the feasibility of adapting a compressed earth block (CEB) machine to produce compressed snow blocks (CSBs) as modular, uniform building units for cold-region applications. Using an AECT Impact 2001A hydraulic press, naturally occurring snow was processed with a snowblower and compacted at maximum operating pressure (i.e., 20,684 kPa) to evaluate block formation, dimensional consistency, and density. The machine successfully produced relatively consistent CSBs, but the initial 3–4 blocks following block height adjustment were generally unsuccessful (e.g., incorrect block height or collapsed/broke) while the machine reached its steady state cyclic condition. These blocks were discarded and excluded from the dataset. The successful CSBs had mean block heights of 7.76 ± 0.56 cm and densities comparable to ice (i.e., 0.83 g/cm³). Variations in block height and mass may be attributed to manual snow loading and minor material impurities. While the dataset is limited, the results warrant further investigation into this technology, particularly regarding CSB strength (i.e., hardness and compressive strength) and performance under variable snow and environmental conditions. Mechanized snow compaction using existing CEB technology is technically feasible and capable of producing uniform, structurally stable CSBs but requires further investigation and modifications to reach its full potential. With design improvements such as automated snow feeding, cold-resistant components, and system winterization, this approach could enable scalable CSB production for rapid, on-site construction of snow-based structures in Arctic environments, supporting the military and civilian needs. Full article