Mechanical Activation of Smectite-Based Nanocomposites for Creation of Smart Fertilizers

This research presents the mechanical creation of smart fertilizers from a mixture of smectite and urea in a 3:2 ratio by using the planetary milling technique. The smectite–urea composites show intercalation between urea and mineral, which increases steadily with increasing activation time. A shift of X-Ray Diffraction basal reflections, intensities of Fourier transform infrared spectroscopy (FTIR) peaks, and weight losses in thermogravimetric analysis (TG) document the systematic crystallo-chemical changes of the composites related to nitrogen interaction with activation. Observations of the nanocomposites by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) corroborate the inference. Nitrogen intercalates with smectite in the interlayer space and remains absorbed either within micro-aggregates or on the surface of activated smectites. Soil leaching tests reveal a slower rate of nitrogen than that of traditional urea fertilizers. Different forms of nitrogen within the composites cause their differential release rates to the soil. The formulated nanocomposite fertilizer enhances the quality and quantity of oat yield.

Synthesis of High Performance Thiophene–Aromatic Polyesters from Bio-Sourced Organic Acids and Polysaccharide-Derived Diol: Characterization and Degradability Studies

In this work, the feasibility of replacing petroleum-based poly(ethylene terephthalate) (PET) with fully bio-based copolyesters derived from dimethyl 2,5-thiophenedicarboxylate (DMTD), dimethyl 2,5-dimethoxyterephthalate (DMDMT), and polysaccharide-derived 1,6-hexanediol (HDO) was investigated. A systematic study of structure-property relationship revealed that the properties of these poly(thiophene–aromatic) copolyesters (PHS(20–90)) can be tailored by varying the ratio of diester monomers in the reaction, whereby an increase in DMTD content noticeably shortened the reaction time in the transesterification step due to its higher reactivity as compared with DMDMT. The copolyesters had weight-average molar masses (Mw) between 27,500 and 38,800 g/mol, and dispersity Đ of 2.0–2.5. The different polarity and stability of heterocyclic DMTD provided an efficient mean to tailor the crystallization ability of the copolyesters, which in turn affected the thermal and mechanical performance. The glass transition temperature (Tg) could be tuned from 70–100 °C, while the tensile strength was in a range of 23–80 MPa. The obtained results confirmed that the co-monomers were successfully inserted into the copolyester chains. As compared with commercial poly(ethylene terephthalate), the copolyesters displayed not only enhanced susceptibility to hydrolysis, but also appreciable biodegradability by lipases, with weight losses of up to 16% by weight after 28 weeks of incubation.

Biobased Terpene Derivatives: Stiff and Biocompatible Compounds to Tune Biodegradability and Properties of Poly(butylene succinate)

Different copolymers incorporating terpene oxide units (e.g., limonene oxide) have been evaluated considering thermal properties, degradability, and biocompatibility. Thus, polycarbonates and polyesters derived from aromatic, monocyclic and bicyclic anhydrides have been considered. Furthermore, ring substitution with myrcene terpene has been evaluated. All polymers were amorphous when evaluated directly from synthesis. However, spherulites could be observed after the slow evaporation of diluted chloroform solutions of polylimonene carbonate, with all isopropene units possessing an R configuration. This feature was surprising considering the reported information that suggested only the racemic polymer was able to crystallize. All polymers were thermally stable and showed a dependence of the maximum degradation rate temperature (from 242 °C to 342 °C) with the type of terpene oxide. The graduation of glass transition temperatures (from 44 °C to 172 °C) was also observed, being higher than those corresponding to the unsubstituted polymers. The chain stiffness of the studied polymers hindered both hydrolytic and enzymatic degradation while a higher rate was detected when an oxidative medium was assayed (e.g., weight losses around 12% after 21 days of exposure). All samples were biocompatible according to the adhesion and proliferation tests performed with fibroblast cells. Hydrophobic and mechanically consistent films (i.e., contact angles between 90° and 110°) were obtained after the evaporation of chloroform from the solutions, having different ratios of the studied biobased polyterpenes and poly(butylene succinate) (PBS). The blend films were comparable in tensile modulus and tensile strength with the pure PBS (e.g., values of 330 MPa and 7 MPa were determined for samples incorporating 30 wt.% of poly(PA-LO), the copolyester derived from limonene oxide and phthalic anhydride. Blends were degradable, biocompatible and appropriate to produce oriented-pore and random-pore scaffolds via a thermally-induced phase separation (TIPS) method and using 1,4-dioxane as solvent. The best results were attained with the blend composed of 70 wt.% PBS and 30 wt.% poly(PA-LO). In summary, the studied biobased terpene derivatives showed promising properties to be used in a blended form for biomedical applications such as scaffolds for tissue engineering.

Weight loss and commodity evaluation of pear fruits during storage depending on the packaging method

Pear fruits have a high biological and nutritional value; however, they are perishable products, storage of which is accompanied by certain difficulties. You can preserve the quality of fresh pears through the use of various packaging methods, among which the use of polyethylene liners is effective. The article presents the results of studies of weight loss and yield of pears during storage, depending on the variety and method of packaging. Conferencia, Noiabrska, and Osnovianska pears of the highest and first commodity varieties were pre-cooled and packed in wooden boxes №3, with a capacity of up to 25 kg (“control” option) and in boxes with a plastic bag liner inserted inside the package 45–50 μm followed by sealing (option “box with a polyethylene liner”). Pear fruits were stored for four months at a temperature of 0 ... + 3 ± 1 ºС and relative humidity of 92% ± 2%. Fruit weight losses were determined by the method of weighing fixed samples, the yield of marketable products - according to DSTU 8326:2015. It was found that during the storage period of pear fruits, their weight loss was 2.3–5%, depending on the variety and method of packaging. In terms of pomological varieties, according to average data, the highest weight loss was pears of the Osnovianska variety – 2.6%. The use of polyethylene liners during the storage of pears helped to reduce losses by 0.5–2.3% depending on the variety and duration of storage. It was found that in the conditions of free air access the share of standard products was 78.6–88.3% with the minimum value in the fruits of Conference and the maximum in the fruits of Noiabrska Moldova. It is proved that packing pear fruits in wooden boxes with polyethylene inserts caused an increase in the yield of marketable products to 90.2–98.4%, a decrease in the share of non-standard products to 1.6–7.0%, and waste to 2.8%. The weight loss of pear fruits of the Noiabrska Moldova variety was 0.3–1.5 lower compared to similar indicators of other varieties. The fruits of the same variety recorded a higher yield of marketable products – 88.3–98.4% depending on the method of storage.

Sucrose, salicylic acid and citric acid solutions to extent vase life of Vriesea incurvata Gaudich. (Bromeliaceae) floral scapes

Vriesea incurvata is a native bromeliad from Brazilian Atlantic Rainforest and commercialized as an ornamental pot plant. The morphological characteristics of its floral scape may also indicate it as a new product to use as a cut flower. However, its postharvest behavior was unknown. This study was conducted to determine its vase life by applying distilled water (control) and solutions containing sucrose (50 g L-1), salicylic acid (50 μM), and citric acid (50 g L-1) for periods of 8 and 24 h. Floral scapes maintained in solutions showed vase life greater than 16 days when compared to the control (distilled water). However, solutions with sucrose evidenced the best behaviors related to the maintenance of physiological and aesthetic features during the vase life of the floral scapes. It is concluded that solutions with sucrose, salicylic acid, and citric acid applied for 8 and 24 h extend the vase life of the V. incurvata floral scapes. Sucrose applied for 8 h promotes the maintenance of color, brightness, and turgidity; improves water balance, and reduces the relative fresh weight losses of floral scapes throughout the vase life, extending their longevity up to 24 days.

ATR-FTIR Study of Alaska Yellow Cedar Extractives and Relationship with Their Natural Durability

New approaches for assessing wood durability are needed to help categorize decay resistance as timber utilization shifts towards plantations or native forest regrowth that may be less durable than original native forest resources. This study evaluated attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with principal component analysis (PCA) for distinguishing between groups of Alaska yellow cedar (Cupressus nootkatensis) wood for susceptibility to two decay fungi (Gloeophyllum trabeum and Rhodonia placenta) and the eastern subterranean termite (Reticulitermes flavipes). Alaska yellow cedar durability varied with test organisms, but the majority of samples were highly resistant to fungal and termite attack. Weight losses and extractives yield using sequential extractions (toluene:ethanol > ethanol > hot water) showed moderate to weak relationships. PCA analysis revealed limited ability to distinguish amongst levels of wood durability to all tested organisms. The absence of non-resistant samples may have influenced the ability of the chemometric methods to accurately categorize durability.

Vapour Application of Sage Essential Oil Maintain Tomato Fruit Quality in Breaker and Red Ripening Stages

Consumers seek safe, high-nutritional-value products, and therefore maintaining fresh produce quality is a fundamental goal in the food industry. In an effort to eliminate chemical-based sanitizing agents, there has been a shift in recent decades toward the usage of eco-friendly, natural solutions (e.g., essential oils-EOs). In the present study, tomato fruits (Solanum lycopersicum L. cv. Dafni) at breaker and red ripening stage were exposed to sage essential oils (EO: 50 μL L−1 or 500 μL L−1) for 2, 7 and 14 days, at 11 °C and 90% relative humidity (RH). Quality-related attributes were examined during (sustain effect—SE) and following (vapour-induced memory effect—ME; seven days vapours + seven days storage) vapour treatment. In breaker tomatoes, EO-enrichment (sustained effect) retained fruit firmness, respiration rates, and ethylene emission in low EO levels (50 μL L−1). In contrast, breaker fruit metabolism sped up in high EO levels of 500 μL L−1, with decreased firmness, increased rates of respiration and ethylene, and effects on antioxidant metabolism. The effects were more pronounced during the storage period of 14 days, comparing to the fruit exposed to common storage-transit practice. In red fruits, the EOs impacts were evidenced earlier (at two and seven days of storage) with increased rates of respiration and ethylene, increased β-carotene, and decreased lycopene content. In both breaker and red ripening fruit, EO application decreased weight losses. Considering the fruits pre-exposed to EOs, quality attributes were more affected in green fruits and affected to a lesser level in the red ones. Furthermore, based on appearance, color, and texture evaluations, organoleptic trials demonstrated an overwhelming preference for EO-treated red fruit during choice tests. EOs had lower effects on total phenolics, acidity, total soluble solids, and fruit chroma, with no specific trend for both breaker and red tomatoes. Natural volatiles may aid to retain fruit quality in parallel with their antimicrobial protection offered during storage and transportation of fresh produce. These effects may persist after the EO is removed from the storage conditions.

Performance of Fiber Self Compacting Concrete at High Temperatures

The goal of this study is to assess the fresh and hardened properties of self-compacting concrete (SCC) prepared using locally available materials. This research includes also the impact of polypropylene (PP), steel and hybrid fibers on the same properties. In addition, the mechanical properties of SCC specimens (with and without fibers) at high temperatures, including as compressive, tensile, and flexural strengths, will be determined. Four different SCC mixtures (with and without fibers) are prepared, tested, and assessed in order to attain these goals. The specimens were heated to various temperatures (200, 400, 600, and 800) at a rate of 5 degrees Celsius per minute for each test. The temperature was remained constant at the target temperature for one hour before cooling to ensure a consistent temperature throughout the specimen. According to the test results, all of the mixes have good consistency and workability in terms of filling and passing ability. In addition, the inclusion of fibers lowered the workability of SCC slightly. Also, the compressive, tensile, and flexural strengths improved with increasing temperature up to 200 °C and dropped at temperatures over 200 °C, according to these findings. Within the SCC, the PP fibers lowered and removed the risk of spalling. Concrete mixtures containing steel fibers and hybrid fibers have the finest mechanical characteristics and spalling resistance as temperature rises. Weight losses were lower in SCC mixtures with PP and steel fibers than in those without PP and steel fibers. As the temperature rose, all SCC mixes lost mass and UPV decreased until the samples spalled (as in plain SCC and SCC with steel fibers) or were questionable (as in SCC with PP and SCC with hybrid fibers). Doi: 10.28991/cej-2021-03091779 Full Text: PDF

АНАЛІЗ МОЖЛИВОСТЕЙ РЕАЛІЗАЦІЇ МОДУЛЬНОГО ПРИНЦИПУ СТВОРЕННЯ МОДИФІКАЦІЙ ПОВІТРЯНИХ СУДЕН ТА ЇХ ЕФЕКТИВНОЇ ЕКСПЛУАТАЦІЇ В СИСТЕМІ ВІТЧИЗНЯНИХ АВІАПЕРЕВЕЗЕНЬ

It is known that an aircraft generates income for the operating airline only when it is in the air. Being on the ground, at the airport, airlines incur high costs for aerodrome maintenance of the aircraft. The longer the aircraft is stationary on the ground, the shorter the actual flight time of the aircraft. In this regard, the possibility of implementing one of the promising principles for the creation and effective operation of modifications of aircraft of the transport category - the modular principle - has been analyzed. The prospects for the implementation of modular modifications in domestic airlines in the context of further development of the market economy are considered. Modifications based on the implementation of the modular principle are classified into two types - created in the form of autonomous modules placed in the fuselage during aircraft operation and in the form of a removable modular compartment of the aircraft fuselage. A review and analysis of existing projects of these types of modular constructive and technological solutions, a comparison of their advantages and disadvantages in the technical and economic aspects of the prospects for their feasibility are carried out. The possibility of effective implementation of the modular principle of modifications of aircraft of the transport category was assessed, for which a generalized analysis of domestic and foreign information related to the state of the problem under discussion was carried out, on the basis of which an enlarged block diagram of a comprehensive methodology for analyzing the efficiency of operation of modular modifications in the air transportation system was synthesized in comparison with traditional (existing). The key aspects of the content of the main blocks of the scheme are revealed, including the main provisions of the maintenance and repair of aircraft in modern conditions of their operation, based on foreign experience, as well as the main aspects of the content of the blocks for accounting for weight losses in the design and implementation of traditional and modular modifications of aircraft. The generalized information related to the implementation of the synthesized block diagram, focused on subsequent addition, should form the basis of compliance methods and regulatory documentation in the design and implementation of promising domestic modifications of aircraft of the transport category.

Influence of Crystallite Size of Nickel and Cobalt Ferrites on the Catalytic Pyrolysis of Buckwheat Straw by Using TGA-FTIR Method

Pyrolysis of buckwheat straw with or without catalysts was investigated using the TGA-FTIR method to determine the influence of nickel and cobalt ferrites on the distribution of pyrolysis products. According to the obtained results, the overall shape of the thermogravimetric and derivative thermogravimetric curves is unchanged in the presence of nickel and cobalt ferrites but different weight losses were observed. All catalysts contribute to the formation of solid residue from BWS pyrolysis. The presence of cobalt ferrites exhibited the highest bio-oil yields, whereas the highest non-condensable gas yield and the lowest bio-oil yield was obtained with the addition of NiFe2O4 (1) catalyst. According to the obtained results, the ability of nickel and cobalt ferrites to catalyze deoxygenation reactions depends on the crystallite size. The nickel or cobalt ferrites with smaller crystallite size (15-22 nm) show a higher ability to catalyzed dehydration reaction than catalysts with larger crystallite size (45-54 nm).