Wall Material Research Articles

Дослідження фізико-механічних властивостей рафінованої міді у якості матеріалу для стінок кристалізаторів МБЛЗ

Дослідження фізико-механічних властивостей рафінованої міді у якості матеріалу для стінок кристалізаторів МБЛЗ

Analyzing the thermal performance of walling systems in low-income housing through computational fluid dynamics approach

The thermal properties of wall materials have a direct impact on the thermal performance of the indoor environment, by also influencing the occupant’s well-being. Coupled with airflow dynamics, the thermal performance of wall materials influences the indoor air temperature distribution thereby impacting thermal comfort, particularly in naturally ventilated (NV) spaces. However, defining the relationships between the wall characteristics, airflow dynamics, and thermal comfort for selecting the appropriate wall material for low-income NV buildings is still not evident in the current literature. Therefore, this study proposes a simulation-based framework that considers the relationships between wall materials, airflow dynamics, and thermal comfort using a computational fluid dynamics (CFD) approach by spatially plotting the thermal comfort within the NV spaces.The study analyses locally accessible wall materials, subjecting them to different operating conditions within NV dwelling units of low-income housing in India. Out of the analyzed wall materials, aerated autoclaved blocks exhibited a significant indoor temperature reduction of 20.7 % compared to the compressed stabilized earth blocks, with constrained airflow exacerbating temperature fluctuations. The global implications of these findings are substantial for urban low-income dwellers experiencing excessive heat. Mass housing efforts worldwide can benefit from using thermally efficient materials in construction thereby improving living conditions, and mitigating the impact of climate change on thermal comfort and health.

Molecular motor tug-of-war regulates elongasome cell wall synthesis dynamics in Bacillus subtilis

Most rod-shaped bacteria elongate by inserting new cell wall material into the inner surface of the cell sidewall. This is performed by class A penicillin binding proteins (PBPs) and a highly conserved protein complex, the elongasome, which moves processively around the cell circumference and inserts long glycan strands that act as barrel-hoop-like reinforcing structures, thereby giving rise to a rod-shaped cell. However, it remains unclear how elongasome synthesis dynamics and termination events are regulated to determine the length of these critical cell-reinforcing structures. To address this, we developed a method to track individual elongasome complexes around the entire circumference of Bacillus subtilis cells for minutes-long periods using single-molecule fluorescence microscopy. We found that the B. subtilis elongasome is highly processive and that processive synthesis events are frequently terminated by rapid reversal or extended pauses. We found that cellular levels of RodA regulate elongasome processivity, reversal and pausing. Our single-molecule data, together with stochastic simulations, show that elongasome dynamics and processivity are regulated by molecular motor tug-of-war competition between several, likely two, oppositely oriented peptidoglycan synthesis complexes associated with the MreB filament. Altogether these results demonstrate that molecular motor tug-of-war is a key regulator of elongasome dynamics in B. subtilis, which likely also regulates the cell shape via modulation of elongasome processivity.

Effects of the spray-drying process using maltodextrin on bioactive compounds and antioxidant activity of the pulp of the tropical fruit açai (Euterpe oleracea Mart.)

Aҫai fruit is characterized by the properties of its bioactive compounds; however, this fruit is highly perishable and its compounds are sensitive when exposed to non-optimal environmental factors. Therefore, the objective of this study was to encapsulate the fruit pulp by spray drying to improve the nutritional value and extend the shelf life of the products derived from acai fruit. Maltodextrin was used as a wall material and the process was optimized to obtain the desirable values of the response variables. For this, a central compound design (CCD) was developed to determine the influence of temperature (110–170 °C) and the wall material proportion (5–15 %) on dependent variables: the retention of ascorbic acid, moisture percentage, hygroscopicity, solubility, water activity, and yield. Furthermore, the effects of spray drying on bioactive compounds (AA, TPC, TFC, TA, TCC, GA, CT, and QC) and antioxidant activity (ABTS, DPPH, and ORAC) were evaluated. The maximum design temperature (170 °C) and wall material proportion (15 %) significantly influenced the response variables where encapsulation was applied, with high ascorbic acid retention (96.886 %), low moisture (0.303 %), low hygroscopicity (7.279 g/100 g), low level of water activity (0.255), a water solubility index of 23.206 %, and a high yield of 70.285 %. The bioactive compounds analyzed and the antioxidant capacity presented significant retention values for AA (96.86 %), TPC (65.13 %), TFC (82.09 %), TA (62.46 %), TCC (7.28 %), GA (35.02 %), CT (49.03 %), QC (37.57 %), ABTS (81.24 %), DPPH (75.11 %), and ORAC (15.68 %). Therefore, it is concluded that the powder obtained under these conditions has desirable physical properties, and the drying process preserved a notable retention of bioactive compounds and their antioxidant activities.

Preparation of inorganic oil-containing carbon nanocapsules and tribological properties of PA6 composites

Oil-containing polymer composites have garnered significant attention in the field of tribology due to their remarkable environmental stability and outstanding self-lubricating performance. It is important to develop an oil-containing polymer composite with excellent self-lubricating properties and mechanical properties. In this study, we successfully synthesized hollow mesoporous carbon nanospheres (HMCNs) with a particle size of about 200 nm and explored the key factors affecting their preparation. Subsequently, an impregnation technique was employed to create oil-containing nanocapsules (Oil@C) by using PAO40 lubricant as core material and HMCNs as wall material. Self-lubricating PAO40@HMCNs nanocapsules have an oil content of approximately 51.6 wt%. The unique mesoporous structure of HMCNs facilitates the controlled release of lubricants. During friction, the Oil@C in the polymer composites continuously provided lubricant to the worn surface, resulting in a remarkable 72.8 % reduction in the coefficient of friction and an 83.2 % decrease in wear rate. Analysis of the friction pair revealed that the PAO40 lubricant released from the nanocapsules played a crucial role in improving the tribological properties of the composites. The prepared PA6 composites exhibit outstanding tribological and self-lubricating properties, making them promising candidates for applications in mechanical parts, such as self-lubricating slide bearings.

Jet milling‐activated direct synthesis of octenyl succinic anhydride modified starch: an analysis of structural and application properties

SummaryThe synthesis of octenyl succinic anhydride‐modified starch was achieved through a fluidised bed activated by jet milling with graded revolution rates of 1200, 1800, 2400, 3000, and 3600 rpm. This study investigated the changes in the structural, physicochemical, and application properties of modified starch after jet milling. The results showed that modified starch can be synthesised using a one‐step jet milling process. The degree of substitution increased with a decrease in the starch particle size, resulting in a rough granule morphology. Structural analysis revealed that crystalline areas were destroyed in the modified starches. In the Fourier‐infrared spectrum, typical peaks appeared at 1724 and 1573 cm−1 upon introduction of the octenyl succinic anhydride group, whereas a new sodium peak appeared in the XPS spectrogram. The 1H‐NMR spectrum indicated that the esterification reaction mainly occurred on OH2 groups. The emulsification properties of the modified starch were significantly enhanced and increased with the crushing strength. The octenyl succinic anhydride‐modified starch has potential as a wall material for microcapsules, with good embedding rate and thermal stability. This novel synthesis method represents an innovative method for the synthesis of OSA‐starches.

Microencapsulation of green tea polyphenols: Utilizing oat oil and starch-based double emulsions for improved delivery

The stability and bioavailability of green tea polyphenols, crucial for their health benefits, are compromised by environmental sensitivity, limiting their use in functional foods and supplements. This study introduces a novel water-in-oil-in-water double emulsion technique with microwave-assisted extraction, significantly enhancing the stability and bioavailability of these compounds. The primary objective of this study was to assess the effectiveness of several encapsulating agents, such as gum Arabic as control and native and modified starches, in improving encapsulated substances' stability and release control. Native and modified starches were chosen for their outstanding film-forming properties, improving encapsulation efficiency and protecting bioactive compounds from oxidative degradation. The combination of maltodextrin and tapioca starch improved phenolic content retention, giving 46.25 ± 2.63 mg/g in tapioca starch microcapsules (GTTA) and 41.73 ± 3.24 mg/g in gum arabic microcapsules (GTGA). Besides the control, modified starches also had the most potent antioxidant activity, with a 45 % inhibition (inh%) in the DPPH analysis. Oat oil was utilized for its superior viscosity and nutritional profile, boosting emulsion stability and providing the integrity of the encapsulated polyphenols, as indicated by the microcapsules' narrow span index (1.30 ± 0.002). The microcapsules' thermal behavior and structural integrity were confirmed using advanced methods such as Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared Spectroscopy (FT-IR). This study highlights the critical role of choosing appropriate wall materials and extraction techniques. It sets a new standard for microencapsulation applications in the food industry, paving the way for future innovations.

Microencapsulation of camellia seed oil by spray drying with pea protein and maltodextrin

The purpose of this study was to extend the shelf life and enhance the oxidative stability of camellia seed oil through microencapsulation. To 2achieve this, we chose pea peptide (PP) and maltodextrin (MD) as the wall materials for microencapsulation and successfully transformed camellia oil into powdered oil using the spray drying method. The preparation conditions were optimized using a univariate method. The preparation conditions were optimized using a univariate method. The best encapsulation effect was achieved when the wall ratio (PP: MD) was 1:1, the wall-to-core ratio was 1.5:1, and the spray drying temperature was 180 °C. The results showed that the embedding rate of camellia seed oil microcapsule (CSOM) could reach 79.69 %, with a particle size below 600 nm. Additionally, the characterization results indicated that the microcapsule products were spherical, with most particles having a smooth surface and no ruptures. CSO was effectively encapsulated within the microcapsules. Furthermore, the oxidative stability of CSOM was superior to that of CSO, and the shelf lives of CSO and CSOM were 35 days and 64 days, respectively. These results demonstrate that microencapsulation technology can effectively extend the shelf life of CSO.

Effects of wall materials on the physicochemical properties of spray-dried bitter gourd (Momordica charantia L.) powders

Bitter gourd has numerous health-promoting effects on the human body. However, its use has been greatly limited due to its poor acceptance by consumers, resulting from its strong bitterness. This study investigated the effects of five wall materials, namely, soybean protein isolate, gum arabic, maltodextrin, resistant starch, and a soybean lecithin calcium caseinate mixture, on the physicochemical properties of spray-dried bitter gourd powders. The results showed that all five wall materials reduced the moisture content, water activity, browning degree, agglomeration, and bitterness of the spray-dried bitter gourd powder. Maltodextrin was found to be the most effective at reducing water activity, while soybean protein isolate was best at protecting the colour, and the soybean lecithin calcium caseinate mixture was best at reducing hygroscopicity and masking bitterness. Additionally, all five wall materials improved the preservation of flavonoids, saponins, and vitamin C, with soybean protein isolate being the most effective in improving the total flavonoid retention ratio and the soybean lecithin calcium caseinate mixture being the best in improving the retention ratios of total saponins and vitamin C. The spray-dried bitter gourd powder prepared with soybean protein isolate had the highest antioxidant activity and α-glucosidase inhibitory activity. These results are significant for understanding the relationship between wall materials and the physicochemical properties of spray-dried powder. Additionally, these materials provide bitter gourd product manufacturers with useful guidance for producing high-quality products. Furthermore, the results could provide useful insights for processing fruits with similar product characteristics, thus contributing to the enrichment of food processing knowledge.

Validation of the ERO2.0 code using W7-X and JET experiments and predictions for ITER operation

The paper provides an overview of recent modelling of global material erosion and deposition in the fusion devices Wendelstein 7-X (W7-X), JET and ITER using the Monte-Carlo code ERO2.0. For validating the modelling tool in a three-dimensional environment, W7-X simulations are performed to describe carbon erosion from the graphite test divertor units, which were equipped in operational phase OP 1.2 and analysed post-mortem. Synthetic spectroscopy of carbon line emission is compared with experimental results from the divertor spectrometer measurement system, showing a good agreement in the e-folding lengths in the radial intensity profiles of carbon. In the case of metallic wall materials, earlier modelling of the Be/W environment in JET and ITER is revisited and extended with an updated set of sputtering and reflection data, as well as including the mixing model for describing the Be/W dynamics in the divertor. Motivated by recent H/D/T isotope experiments in JET, limited and diverted configuration pulses are modelled, showing the expected trend of both Be and W erosion increasing with isotope mass. For the JET diverted configuration pulses, it is shown that Be migrates predominantly to the upper part of the inner divertor where it initially leads to strong W erosion. With longer exposure time, the growth of a Be deposited layer leads to a reduction of W erosion in that region. A similar trend is observed in simulations of the ITER baseline Q = 10 scenario, however with a more symmetric Be migration pattern leading to deposition also on the outer divertor.

Alternative green wall materials

Spray drying is still the most significant method for polyphenols encapsulation, which offers numerous advantages such as facilitating the handling of unstable polyphenols from liquid extracts, improving their solubility, and enhancing stability, degradation protection, controlling or delaying the release, and masking unappealing tastes or odours. The selection of the most suitable wall material is one of the most challenging tasks. Over the past decade, there has been a growing trend toward using new types of wall materials for polyphenols encapsulation by spray drying, either as additional compounds or as complete substitutes for traditional wall materials. This review aims to present the properties and applications of such alternative green wall materials. The term “alternative green” refers to the origin of materials derived from by-products and waste.

A Comparative Study of Encapsulation of β-Carotene via Spray-Drying and Freeze-Drying Techniques Using Pullulan and Whey Protein Isolate as Wall Material.

The encapsulation of β-carotene was investigated using pullulan and whey protein isolate (WPI) as a composite matrix at a weight ratio of 20:80, employing both spray-drying and freeze-drying techniques. The influence of processing parameters such as the concentration of wall material, flow rate, and inlet temperature for SP encapsulants, as well as wall-material concentration for FZ encapsulants, was examined in terms of encapsulation efficiency (EE). The morphology, structural characterization, moisture sorption isotherms, and thermal properties of the resulting encapsulants at optimum conditions were determined. Their stability was investigated under various levels of water activity, temperature conditions, and exposure to UV-Vis irradiation. β-carotene was efficiently encapsulated within SP and FZ structures, resulting in EE of approximately 85% and 70%, respectively. The degradation kinetics of β-carotene in both structures followed a first-order reaction model, with the highest rate constants (0.0128 day-1 for SP and 0.165 day-1 for FZ) occurring at an intermediate water-activity level (aw = 0.53) across all storage temperatures. The photostability tests showed that SP encapsulants extended β-carotene's half-life to 336.02 h, compared with 102.44 h for FZ encapsulants, under UV-Vis irradiation. These findings highlight the potential of SP encapsulants for applications in functional foods, pharmaceuticals, and carotenoid supplements.

Inhibited the walnut oil oxidation through the microcapsules that consisted of (−)-Epigallocatechin gallate and sodium caseinate

(−)-Epigallocatechin gallate (EGCG) possesses potent antioxidant properties and can enhance the encapsulation efficiency and stability of oil microcapsule with sodium caseinate (NaCas). Hence, the present study aimed to investigate the effects of different concentrations of EGCG on the physicochemical properties of walnut oil microcapsules. The impact of EGCG on the morphology, structure, physical attributes, and functional traits of walnut oil microcapsules was characterized through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, molecular docking, thermogravimetric analysis, etc. Results demonstrated that EGCG interacted with NaCas via hydrogen bonding and hydrophobic interactions to form walnut oil microcapsules, significantly enhancing the encapsulation efficiency up to 86.42%. With increasing concentration of EGCG, the NaCas-EGCG complex displayed heightened DPPH free radical scavenging capacity (up to 68.27 μg Trolox/mL). Furthermore, in vitro digestion indicated that the microcapsules could effectively regulate the release rate of free fatty acids. In conclusion, the present study successfully prepared walnut oil microcapsules with elevated oxidative stability by employing EGCG and NaCas as the wall materials, providing new insight for preparing walnut oil microcapsules with improved stability and release properties.

Roles of the Arabidopsis KEULE Gene in Postembryonic Development.

Cytokinesis in plant cells begins with the fusion of vesicles that transport cell wall materials to the center of the cell division plane, where the cell plate forms and expands radially until it fuses with the parental cell wall. Vesicle fusion is facilitated by trans-SNARE complexes, with assistance from Sec1/Munc18 (SM) proteins. The SNARE protein KNOLLE and the SM protein KEULE are required for membrane fusion at the cell plate. Due to the crucial function of KEULE, all Arabidopsis (Arabidopsis thaliana) keule mutants identified to date are seedling lethal. Here, we identified the Arabidopsis serrata4-1 (sea4-1) and sea4-2 mutants, which carry recessive, hypomorphic alleles of KEULE. Homozygous sea4-1 and sea4-2 plants are viable and fertile but have smaller rosettes and fewer leaves at bolting than the wild type. Their leaves are serrated, small, and wavy, with a complex venation pattern. The mutant leaves also develop necrotic patches and undergo premature senescence. RNA-seq revealed transcriptome changes likely leading to reduced cell wall integrity and an increase in the unfolded protein response. These findings shed light on the roles of KEULE in postembryonic development, particularly in the patterning of rosette leaves and leaf margins.

Glass Bottle Earth Brick for Structural Wall

Brazil has a low percentage of recycled container glass due to multiple factors, such as inadequate waste collection and recycling infrastructure, low public awareness about recycling's significance, and insufficient laws to promote it. In addition, the country faces high levels of homelessness and inadequate housing. As a result, an increasing number of builders are exploring repurposing glass bottles as a construction material for walls, occasionally incorporating them into traditional earthen building techniques. Therefore, this paper investigates the potential of prefabricated earthcrete bricks that integrate glass container bottles for the construction of structural load-bearing walls for affordable housing in Brazil while at the same time reducing pollution, enhancing aesthetics, and promoting environmental friendliness. Initially, the mechanical behaviour of the container glass bottles in earth bricks is investigated through FEM modelling. Subsequently, prototypes are made and tested in the laboratory, revealing a compressive strength between 8.21 and 11.40 MPa. From these findings, it is concluded that reusing glass bottles for the construction of structural walls capable of supporting small-scale structures could be feasible.

Sound absorption and thermal insulation materials from waste palm oil for housing application: Green polyurethane/water hyacinth fiber sheet composite

This research presents an eco-friendly method for producing polyurethane foam (PUF) and water hyacinth fiber (WHF) sheets. The objectives were to engineer wall materials with sound-absorption and thermal insulation capabilities while also improving the mechanical properties of pure PUF. Waste palm oil (WPO) was successfully utilized as a polyol substrate, playing a substantially role in PUF generation, acting as a PU binder, and serving as a PU adhesive. The productions of PUF (NCO index of 100) combined with WHF sheets (WHF/PU binder ratio of 60/40) using four distinct fabrication methods (sheet-foam-sheet (SFS), foam-sheet-foam (FSF), foam-foam-foam (FFF), and sheet-sheet-sheet (SSS)) were investigated with a fabrication thickness of 150 mm. The findings indicate that the SFS configuration demonstrates remarkable sound absorption properties, with an average sound absorption (SAA) of 0.59, noise reduction coefficient (NRC) of 0.39, and the highest sound absorption coefficient (SAC) of 0.93 at 1900 Hz, alongside a thermal conductivity of 0.0301 W/mK. Importantly, all four methodologies produce SAC values greater than 0.4, outperforming commercial counterparts while demonstrating low thermal conductivity indicative of effective thermal insulation. The result noted that WHF sheet exhibited self-extinguishing properties, making them suitable for use in construction materials. As a result, SFS emerges as the best method for constructing superior sound absorption and thermal insulation materials. This study emphasizes the potential of waste derived WPO and WHF as advantageous eco-friendly substrates for industrial wall and housing materials.

Encapsulation of betacyanin extract from red dragon fruit peel with maltodextrin and inulin: Storage stability and simulated gastrointestinal digestion

Betacyanins are bioactive pigments found in red dragon fruit peels with potential health benefits, but their stability and bioaccessibility are low. This study aimed to investigate the impact of using dietary fiber inulin (IN) combined with malrodextrin (MD) as wall materials for the encapsulation of betacyanin on its physicochemical properties, storage stability, and in vitro release behavior. Different concentrations of MD and IN were tested at 30% MD + 10% IN (T1), 20% MD + 20% IN (T2), 10% MD + 30% IN (T3), and 40% MD (control). The results showed that the combination of MD and IN reduced the moisture content and water activity, increased the drying yield, and improved the hygroscopy and solubility of betacyanin extract. Furthermore, the T3 combination showed the highest encapsulation efficiency, betacyanin (BTC), phenolic content (TPC), flavonoid content (TFC), as well as antioxidant activity. FTIR analysis confirmed the effective encapsulation of betacyanin. The T1 combination exhibited the lowest degradation constant (k) and the longest stability of betacyanin storage half-life (t1/2 = 99 weeks). Additionally, the combination of MD and IN effectively improved the stability of betacyanins during simulated gastrointestinal digestion, improving the bioaccessibility of betacyanin with higher concentrations of IN (T3), resulting in the higher bioaccessibility of betacyanin (57.11%). In conclusion, this study demonstrates that the use of a combination of MD and IN as dietary fiber wall materials can improve the stability and bioaccessibility of betacyanin extract, ultimately leading to its wider utilization and potential health benefits as functional natural food colorants.

Design and optimization of THz coupling in zirconia MAS rotors for dynamic nuclear polarization NMR

We present 3D electromagnetic simulations of the coupling of a 250 GHz beam to the sample in a 380 MHz DNP NMR spectrometer. To obtain accurate results for magic angle spinning (MAS) geometries, we first measured the complex dielectric constants of zirconia, sapphire, and the sample matrix material (DNP juice) from room temperature down to cryogenic temperatures and from 220 to 325 GHz with a VNA and up to 1 THz with a THz TDS system. Simulations of the coupling to the sample were carried out with the ANSYS HFSS code as a function of the rotor wall material (zirconia or sapphire), the rotor wall thickness, and the THz beam focusing (lens or no lens). For a zirconia rotor, the B1 field in the sample was found to be strongly dependent on the rotor wall thickness, which is attributed to the high refractive index of zirconia. The optimum thickness of the wall is likely due to a transmission maximum but is offset from the thickness predicted by a simple calculation for a flat slab of the wall material. The B1 value was found to be larger for a sapphire rotor than for a zirconia rotor for all cases studied. The results found in this work provide new insights into the coupling of THz radiation to the sample and should lead to improved designs of future DNP NMR instrumentation.

Dicyclohexylcarbodiimide and disodium succinate regulate the pulp softening and breakdown in fresh longan by modulating the metabolism of cell wall polysaccharides

Cell wall polysaccharides (CWP) are an important component of cell structure, and its content variation is a primary factor affecting the texture of fresh longan. The influences of dicyclohexylcarbodiimide (DCC) and disodium succinate (DS) treatments on the pulp softening and pulp breakdown, and their relation to CWP metabolism in pulp of longan fruit were explored. Compared with the control longan, DCC-treated fruit showed lower value of pulp firmness, higher index of pulp breakdown, higher expression levels of cell wall disassembly enzymes (CWDEs)-related genes (DlPME1, DlPME3, DlPG1, Dlβ-Gal1, Dlβ-Gal16, DlCx7, DlXET3, DlXET27), and higher activities of CWDEs including pectin methyl esterase (PME), polygalacturonase (PG), β-galactosidase (β-Gal), cellulase (Cx), xyloglucan endotransglycosylase (XET), lower values of cell wall materials, and lower levels of CWP including ionic-soluble pectin, covalent-soluble pectin, cellulose, and hemicellulose. Whereas, the opposite effects were exhibited in DS-treated fruit. The above data indicate that DCC-hastened longan pulp softening and pulp breakdown was due to the up-regulating expressions of CWDEs-related genes, the activating activities of CWDEs, and the accelerating CWP disassembly by DCC treatment. Whereas, DS repressed longan pulp softening and pulp breakdown through down-regulating the expressions of CWDEs-related genes, inhibiting CWDEs activities, and reducing CWP degradation.

An Approach for Using Non-purified β-Galactosidase: The Potential of β-Galactosidase in Kluyveromyces marxianus Cell Microparticles with Different Wall Materials

An Approach for Using Non-purified β-Galactosidase: The Potential of β-Galactosidase in Kluyveromyces marxianus Cell Microparticles with Different Wall Materials