Wall Material Research Articles

Extrusion and Co-extrusion: A Technology in Probiotic Encapsulation with Alternative Materials.

Encapsulation, in particular extrusion and co-extrusion, is a common practice to protect probiotics from the harsh conditions of the digestive tract as well as processing. Hydrocolloids, including proteins and carbohydrates, natural or modified, are a group of ingredients used as the wall material in extrusion. Hydrocolloids, due to their specific properties, can significantly improve the probiotic survivability of the final powder during the microencapsulation process and storage. The present article will discuss the different kinds of hydrocolloids used for microencapsulation of probiotics by extrusion and co-extrusion, along with new sources of novel gums and their potential as wall material.

On the Relative Effects of Wall and Intraluminal Thrombus Constitutive Material Properties in Abdominal Aortic Aneurysm Wall Stress.

An abdominal aortic aneurysm (AAA) is a dilation localized in the infrarenal segment of the abdominal aorta that can expand continuously and rupture if left untreated. Computational methods such as finite element analysis (FEA) are widely used with in silico models to calculate biomechanical predictors of rupture risk while choosing constitutive material properties for the AAA wall and intraluminal thrombus (ILT). In the present work, we investigated the effect of different constitutive material properties for the wall and ILT on 21 idealized and 10 unruptured patient-specific AAA geometries. Three material properties were used to characterize the wall and two for the ILT, leading to six material model combinations for each AAA geometry subject to appropriate boundary conditions. The results of the FEA simulations indicate significant differences in the average peak wall stress (PWS), 99th percentile wall stress (99th WS), and spatially averaged wall stress (SAWS) for all AAA geometries subject to the choice of a material model combination. Specifically, using a material model combination with a compliant ILT yielded statistically higher wall stresses compared to using a stiff ILT, irrespective of the constitutive equation used to model the AAA wall. This work provides quantitative insight into the variability of the wall stress distributions ensuing from AAA FEA modeling due to its strong dependency on population-averaged soft tissue material characterizations. This dependency leads to uncertainty about the true biomechanical state of stress of an individual AAA and the subsequent assessment of its rupture risk.

Analysis of airtightness performance of residential areas in Mediterranean climate: Balıkesir houses

Airtightness is one of the crucial physical characteristics of building envelope that affect the building thermal performance and energy consumption. The airtightness of the building is influenced by the quality of workmanship and various design parameters such as window/wall ratio, type of joinery, size of the usage area, wall material, and thermal insulation on the external wall. In this study aiming to determine the airtightness performance of buildings in the Mediterranean climate of Balıkesir houses, airtightness conditions of 43 different houses were determined by blower door test measurement. The air exchange rate (n50) values of 43 houses/residences were obtained between 1.94 and 49.02 h−1 and compared with the current various standards. The effect level of the design parameters on the air tightness of the building envelope was obtained as a result of the analysis performed with analysis of variance and post hoc methods. According to the analysis, joinery type was the most effective design parameter in terms of airtightness, followed by usage area and transparency of facades. The result will help in deciding on the design parameters affecting the airtightness of the building envelope for energy efficiency in the Mediterranean climate.

Does Encapsulation Improve the Bioavailability of Polyphenols in Humans? A Concise Review Based on In Vivo Human Studies

Background/Objectives: Polyphenols offer an array of health benefits that can contribute to well-being. Nevertheless, their bioactivity can be compromised due to their low bioavailability. Encapsulation has been explored as a strategy to enhance the stability and bioavailability of polyphenols. During encapsulation, polyphenols are protected from degradation by a wall material that acts as a protective coating. This coating shields the polyphenols from the harsh physiological conditions of digestion, ensuring their delivery to the intestine. However, the majority of evidence, particularly regarding bioavailability after digestion, is derived from in vitro studies. While these studies provide valuable preliminary insights, they cannot definitively confirm the effects in vivo due to their inability to accurately replicate physiological conditions and the complex gut microbial ecosystem. Consequently, this review seeks to evaluate the current evidence from in vivo human studies to elucidate the efficacy of encapsulation in improving polyphenols’ bioavailability. Results and conclusions: Current clinical evidence on the impact of encapsulation on polyphenol bioavailability is primarily focused on polyphenols derived from grape pomace, cocoa, and bilberries, as well as individual polyphenols such as fisetin, hesperidin, and curcumin. Encapsulation has been an effective technique in improving the bioavailability of individual polyphenols like hesperidin, fisetin, and curcumin. However, this approach has not yielded consistent results when applied to groups of polyphenols, such as bilberry anthocyanins or cocoa phenolic acids. Encapsulation by micellization has shown promising results in improving the bioavailability of curcumin in a nutraceutical context. Further studies are needed to explore the bioavailability of encapsulated polyphenols, especially in the functional food context.

The Influence of Material Properties and Wall Thickness on Predicted Wall Stress in Ascending Aortic Aneurysms: A Finite Element Study.

Finite element analysis (FEA) has been used to predict wall stress in ascending thoracic aortic aneurysm (ATAA) in order to evaluate risk of dissection or rupture. Patient-specific FEA requires detailed information on ATAA geometry, loading conditions, material properties, and wall thickness. Unfortunately, measuring aortic wall thickness and mechanical properties non-invasively poses a significant challenge, necessitating the use of non-patient-specific data in most FE simulations. This study aimed to assess the impact of employing non-patient-specific material properties and wall thickness on ATAA wall stress predictions. FE simulations were performed on 13 ATAA geometries reconstructed from computed tomography angiography (CTA) images. Patient-specific material properties and wall thicknesses were made available from a previous study where uniaxial tensile testing was performed on tissue samples obtained from the same patients. The ATAA wall models were discretised with hexahedral elements and prestressed. For each ATAA model, FE simulations were conducted using patient-specific material properties and wall thicknesses, and group-mean values derived from all tissue samples included in the same experimental study. Literature-based material property and wall thickness were also obtained from the literature and applied to 4 representative cases. Additional FE simulations were performed on these 4 cases by employing group-mean and literature-based wall thicknesses. FE simulations using the group-mean material property produced peak wall stresses comparable to those obtained using patient-specific material properties, with a mean deviation of 7.8%. Peak wall stresses differed by 20.8% and 18.7% in patients with exceptionally stiff or compliant walls, respectively. Comparison to results using literature-based material properties revealed larger discrepancies, ranging from 5.4% to 28.0% (mean 20.1%). Bland-Altman analysis showed significant discrepancies in areas of high wall stress, where wall stress obtained using patient-specific and literature-based properties differed by up to 674kPa, compared to 227kPa between patient-specific and group-mean properties. Regarding wall thickness, using the literature-based value resulted in even larger discrepancies in predicted peak stress, ranging from 24.2% to 30.0% (mean 27.3%). Again, using the group-mean wall thickness offered better predictions with a difference less than 5% in three out of four cases. While peak wall stresses were most affected by the choice of mechanical properties or wall thickness, the overall distribution of wall stress hardly changed. Our study demonstrated the importance of incorporating patient-specific material properties and wall thickness in FEA for risk prediction of aortic dissection or rupture. Our future efforts will focus on developing inverse methods for non-invasive determination of patient-specific wall material parameters and wall thickness.

Bioactive compounds delivery and bioavailability in structured edible oils systems.

The health benefits of bioactive compounds are dependent on the amount of intake as well as on the amount of these compounds that become bioavailable and bioaccessible. Various systems have been developed to deliver and increase the bioaccessibility of bioactive compounds. This review explores the impact of gelled (oleogels, bigels, emulgels, emulsions, hydrogels, and hydrogel beads), micro-(gels, particles, spheres, capsules, emulsions, and solid lipid microparticles) and nanoencapsulated systems (nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, liposomes, and nanoliposomes) on the digestibility and bioavailability of lipophilic and hydrophilic bioactives. Structurant molecules, the oil type, antioxidants, emulsifiers, and coatings in delivery systems with promising potential in food applications are critically discussed. The release and bio-accessibility of bioactive compounds in gelled systems are influenced by various factors, such as the type and concentration of gelators, the gelator-to-oil ratio, the type of antioxidant, the network of the system, and its hydrophobicity. The stability, bioaccessibility, and controlled release of bioactives were improved in structured emulsions. Several variables, including wall material, oil/water ratios, encapsulation process, and pH conditions, can affect the bioactives release in microencapsulated systems. Factors like coating type and core-to-wall ratio impact the stability and release of core components. The encapsulating material, the encapsulation technology, and the nature of the nanomaterials all have an impact on the bioaccessibility of nanoencapsulated systems. Nanoliposomes provide enhanced stability and absorption. In general, all encapsulated systems have shown great potential in improving the distribution and availability of bioactive compounds.

Microencapsulated carotenoids from orange sweet potato: Degradation kinetics and physicochemical properties

AbstractThe use of natural pigments in the food industry has increased due to their health benefits. Carotenoids are natural pigments that carry the disadvantage of sensitivity to temperature, light and the presence of enzymes and oxygen. Microencapsulation technology is widely used to protect these compounds against degradation, preserving their physicochemical characteristics. The research objective was to obtain the kinetics of carotenoid degradation of a microencapsulated extract of orange‐fleshed sweet potato (Ipomoea batatas L.) and to establish its physicochemical properties. The sweet potato extract was obtained using ultrasound and then microencapsulated by spray drying using maltodextrin as the wall material. The microencapsulate obtained was subjected to degradation kinetics at 30, 40 and 50°C. Carotenoid quantification analysis, colour, rehydration properties, antioxidant capacity, Fourier‐transform infrared (FTIR) and RAMAN spectroscopy and microstructural characterisation were performed on the microencapsulated carotenoids. From the kinetic analysis, the activation energy of the sweet potato extract was 16.31 kJ/mol while that of the microencapsulated sweet potato extract was 10.27 kJ/mol. Thus, it can be concluded that the microencapsulation process improved the stability of carotenoids subjected to thermal conditions. FTIR and RAMAN spectra confirmed the microencapsulation of the carotenoids. The microencapsulated powder showed a hygroscopicity of 0.22 g/100 g, wettability of 49 s and high solubility. The results obtained in the kinetics are a useful tool to predict losses during the process of heating the carotenoids from sweet potato, thus allowing improvement and selection of the products to which this powder can be applied, in either thermal or cold processes.

Preparation and characterization of high-methoxyl pectin/glycerides emulsion for pH-responsive, targeting, and sustained release of fat-soluble substances

In this study, a pH-responsive emulsion system was prepared, combining high-methoxyl pectin (HMP) with camellia oil glycerides (CG). The emulsion was characterized as O/W type, with HMP serving as the wall material and CG as the oil phase. The physicochemical properties, pH responsiveness, digestion stability, and encapsulated delivery capabilities of the HMP-CG emulsion were investigated. The emulsion showed an average droplet size of 480.47 ± 76.19 nm, possessing a negative charge and a pronounced core-shell structure. HMP package CG enhanced hydrophilic ability and enabled targeted release within the small intestine through the structural changes of HMP. The presence of HMP and CG increased droplet dispersion and target digestibility of the emulsion system, leading to sustainable small intestine-specific release. Overall, HMP-CG emulsion system, composed of natural materials, exhibited the ability to achieve targeted and controllable release via pH-responsive mechanisms, offering an alternative for developing gel materials incorporating fat-soluble substances.

Enhancing indoor PM2.5 predictions based on land use and indoor environmental factors by applying machine learning and spatial modeling approaches

The presence of fine particulate matter (PM2.5) indoors constitutes a significant component of overall PM2.5 exposure, as individuals spend 90% of their time indoors; however, personal monitoring for large cohorts is often impractical. In light of this, this study seeks to employ a novel geospatial artificial intelligence (Geo-AI) coupled with machine learning (ML) approaches to develop indoor PM2.5 models. Multiple predictor variables were collected from 102 residential households, including meteorological data; elevation; land use; indoor environmental factors including human activities, building characteristics, infiltration factors, and real-time measurements; and various other factors. Geo-AI, which integrates land use regression, inverse distance weighting, and ML algorithms, was utilized to construct outdoor PM2.5 and PM10 estimates for residential households. The most influential variables were identified via correlation analysis and stepwise regression. Three ML methods, namely support vector machine, multiple linear regression, and multilayer perceptron (MLP) were used to estimate indoor PM2.5 concentration. Then, MLP was employed to blend three ML algorithms. The resulting model demonstrated commendable performance, achieving a 10-fold cross-validation R2 of 0.92 and a root mean square error of 2.3 μg/m3 for indoor PM2.5 estimations. Notably, the combination of Geo-AI and ensembled ML models in this study outperformed all other individual models. In addition, the present study pointed out the most influential factors for indoor PM2.5 model were outdoor PM2.5, PM2.5/PM10 ratio, sampling month, infiltration factor, located near factory, cleaning frequency, number of door entrance linked with outdoor, and wall material. Further exploration of diverse ensemble model formats to integrate estimates from different models could enhance overall performance. Consequently, the potential applications of this model extend to estimating real individual exposure to PM2.5 for further epidemiological research. Moreover, the model offers valuable insights for efficient indoor air quality management and control strategies.

Environmental impacts of mechanically stabilised earth walls

Mechanically stabilised earth (MSE) walls have gained widespread popularity in North America because of their cost-effectiveness and reliable performance. Although the use of carbon-intensive materials for MSE walls is significantly lower compared to conventional retaining walls like concrete gravity walls and cantilever walls, heavy earthwork and transportation activities are involved in the construction of MSE walls, which increase their carbon footprint. The intensity of construction and transportation activities need particular attention because these are heavily reliant on the combustion of fossil fuels. In this study, the environmental impacts of MSE walls, reinforced by two common types – steel strips and geogrid – are quantified using life cycle assessment (LCA). A parametric study is conducted to investigate the effects of (i) soil properties, (ii) material properties of reinforcement, (iii) applied load, (iv) design parameters, and (v) hauling distances of materials on the global warming impact of MSE walls. Based on the study, reference charts are developed for the purpose of quick estimation of global warming impact of MSE walls based on design dimensions, applied load, and site conditions.

Influence of Cell Wall Material and Cell Numbers on Mechanical Properties of Closed-Cell Aluminum Foams

Influence of Cell Wall Material and Cell Numbers on Mechanical Properties of Closed-Cell Aluminum Foams

The analytical model of flame characteristics of hydrogen–air through wall and gas interaction analysis

AbstractIn this article, the effect of different boundary conditions and different thermal and physical properties of walls and gas on flame characteristics and stability of hydrogen–air mixture are investigated using an analytical method. This method solves the gas–wall energy equation, and the hydrogen mass conservation equations. The jump conditions are obtained by integrating the energy and mass equation into a small control volume around the flame. For validation of this model, the temperature distribution on the outer surface of the wall is compared with experimental data that show the maximum relative error of 3.5% for Q = 400 mL/min and 4.9% for Q = 200 mL/min. The maximum variation of gas temperature is nearly 6.5 times of wall temperature variation. The wall can be considered one‐dimensional for conventional wall materials with K > 10. For the existence of combustion inside the chamber, when the value of K is greater than 10, the Péclet number should also be considered greater than 10. In a constant equivalence ratio, increasing the medium temperature increases flame stability.

Mathematical thermo‐mechanical analysis on flame‐solid interaction: Steady laminar stagnation flow flame stabilized at a plane wall coupled with thermo‐elasticity model

AbstractA laminar stagnation flow flame stabilized at a plane wall is theoretically analyzed, coupled with a thermo‐elasticity model in the wall. Mathematical models for both the flame and the wall will be proposed, and corresponding analytical solutions based on their dimensionless forms will be obtained. The mathematical analysis of this flame‐solid interaction primarily focuses on the effect of the flame on combustion‐induced thermo‐mechanical stresses and the influence of wall material on flame properties such as flame temperature and stability against extinction. A sensitivity analysis is further performed to examine how thermo‐mechanical stress inside the wall is affected by changes in other combustion conditions (e.g., mixture composition, flame stretch rate). This study offers valuable insights into understanding the interaction between flames and solids, a relationship crucial in engineering applications such as the interaction between combustion processes and blades within gas turbine machinery.

Design and performance analysis of a net-zero energy building in Owerri, Nigeria

Building cooling load depends on heat gains from the outside environment. Appropriate orientation and masonry materials play vital roles in the reduction of overall thermal loads buildings. A net-zero energy building performance has been analyzed in order to ascertain the optimum orientation and wall material properties, under the climatic conditions of Owerri, Nigeria. Standard cooling load estimation techniques were employed for the determination of the diurnal interior load variations in a building incorporating renewable energy as the major energy source, and compared with the situation in a conventionally powered building. The results show a 19.28% reduction in the building’s cooling load when brick masonry was used for the wall construction. It was observed that a higher heat gain occurred when the building faced the East-West direction than when it was oriented in the North-South direction. Significant diurnal cooling loads variation as a result of radiation through the windows was also observed, with the east facing windows contributing significantly higher loads during the morning hours while the west facing windows contributed higher amounts in the evening. The economic analysis of the net-zero energy building showed an 11.63% reduction in energy cost compared to the conventional building, with a 7-year payback period for the use of Solar PV systems. Therefore, the concept of net-zero energy building will not only help in energy conservation, but also in cost savings, and the reduction of carbon footprint in the built environment.

Laser-Induced Ablation and Desorption of Deuterium-Containing Tungsten Films

The laser-induced desorption (LID) and laser-induced ablation (LIA) methods are compared with each other regarding the possibility of measurements an absolute quantitative analysis of hydrogen isotopes content in first wall materials of fusion reactors. Deuterium containing tungsten films with a thickness of 300–400 nm on a silicon substrate were used as model samples. To implement the LID, the samples were irradiated with laser pulses with a duration of 200 microseconds and an energy density of 50–150 J/cm2, for LIA – 12 ns and 5–15 J/cm2. The registration of residual gases was carried out by quadrupole mass spectrometry. Computer simulation of laser pulse heating was performed for the LID process. The simulation results and experimental data showed that heating at an energy density of 100–150 J/cm2 is sufficient to degas tungsten films of the studied thickness. A comparison of the amount of desorbed deuterium in the LID (150 J/cm2) and LIA (15 J/cm2) modes shows that it is identical within the measurement error and is equal to 4.15±0.15·1014 cm-2.

Fabrication, characterization and simulated gastrointestinal digestion of sea buckthorn pulp oil microcapsule: effect of wall material and interfacial bilayer stabilization.

Sea buckthorn (Hippophae rhamnoides L.) pulp oil is rich in functional components; however, low water solubility and stability limit its applications. This study fabricated sea buckthorn pulp oil microcapsules using whey protein isolate (WPI), soy protein isolate (SPI), sodium caseinate (NaCN), gum arabic (GA), starch sodium octenylsuccinate (OSAS) and SPI mixed with chitosan (CHI). The influences of these wall materials on physicochemical properties, release behavior and digestibility were explored. Protein-based wall materials (WPI, NaCN, SPI) demonstrated lower bulk densities due to their porous structures and larger particle sizes, while GA and OSAS produced denser microcapsules. Encapsulation efficiency was the highest for protein-based microcapsules (79.41-89.12%) and the lowest for GA and OSAS. The surface oil percentage of protein-based microcapsules (1.41-4.40%) was lower than that of the other microcapsules. Protein-based microcapsules showed concave and cracked surfaces, while GA and OSAS microcapsules were spherical and smooth. CHI improved reconstitution performance, leading to faster dissolution. During simulated gastrointestinal digestion, protein-based microcapsules released more free fatty acids (FFAs) in the intestinal phase, while CHI-modified SPI microcapsules showed a delayed release pattern due to thicker walls. Protein-based wall materials were more effective for sea buckthorn pulp oil microencapsulation, providing higher encapsulation efficiency, better flow properties and releasing more FFAs. The addition of CHI led to the layer-by-layer self-assembly of the microcapsule wall and resulted in sustained release during in vitro intestinal digestion. These findings suggested the potential of protein-based microcapsules for targeted delivery and improved applications of bioactive oils in the food industry. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

MUF-n-Octadecane Phase-Change Microcapsules: Effects of Core pH and Core-Wall Ratio on Morphology and Thermal Properties of Microcapsules.

Phase change energy storage microcapsules were synthesized in situ by using melamine-formaldehyde-urea co-condensation resin (MUF) as wall material, n-octadecane (C18) as core material and styryl-maleic anhydride copolymer (SMA) as emulsifier. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis were used to study the effects of emulsifier type, emulsifier dosage, core-wall ratio and pH on the morphology and thermal properties of microcapsules. The results show that the pH of core material and the ratio of core to wall have a great influence on the performance of microcapsules. SMA emulsifiers and MUF are suitable for the encapsulation of C18. When the pH is 4.5 and the core-wall ratio is 2/1, the latent heat and encapsulation efficiency of phase transition reaches 207.3 J g-1 and 84.7%, respectively. The prepared phase-change microcapsules also have good shape stability and thermal stability.

Utilization Status of Oil-Based Drilling Cutting Pyrolysis Residues in The Field of Building Materials

The exploitation of shale gas generates a large amount of oil-based drill cuttings, which are harmful to the environment due to their content of petroleum hydrocarbons, heavy metals, and organic pollutants. Thermal desorption technology is one of the main techniques for treating oil-based drill cuttings. This paper focuses on oil-based drilling cutting pyrolysis residues and summarizes its current research status in the construction materials field. Currently, the application of oil-based drilling cutting pyrolysis residues has achieved certain results in road fill, cement production, ceramsite production, and wall materials, and further exploration and development are needed in the future to develop high value-added products and expand the pathways for the high-value utilization of oil residues.

Life cycle assessment and generative design: development of a national LCA tool for exterior walls

PurposeThe promotion of sustainable design is demanded globally. The life cycle assessment (LCA) proved its reliability in this mission, but the difficulty and time required to apply it discouraged designers. This research aims to integrate LCA into the building design process through a software tool, taking advantage of generative design features. This will facilitate decision-making by architects and construction professionals.Design/methodology/approachThe study develops the EGY-LCA (http://egy-lca.com/). This prototype tool suggests exterior wall design alternatives for residential buildings in Egypt, using the environmental impact indicators of LCA data and other criteria related to national codes, materials, construction methods and required thermal resistance. Within a generative design process, the algorithm tests every possible wall method with materials and thickness combinations for each layer in compliance with inputs. The paper begins by explaining the tool’s working method. Afterward, different sets of inputs are examined and the values of the resultant environmental impacts of several suggested wall solutions are statistically analyzed. The application demonstrates the importance of the generative design tool. Proposing several solutions based on a set of inputs facilitates the selection of sustainable choices and allows comparisons between alternatives.FindingsThe prototype experiment confirms the research hypothesis. Unlike the available LCA tools, architects can make decisions with limited LCA experience if the data and equations are integrated into a generative design tool. The prototype proves its applicability for exterior wall alternatives.Research limitations/implicationsThe prototype is the initial step toward a whole-building LCA tool. It includes limited LCA stages and materials for the external wall. Future research is required to expand this parametric tool concept to include all the building components. The framework in Section 5 proposes a visualization.Practical implicationsThe prototype tool: EGY-LCA (http://egy-lca.com/). The value added to the design and construction sectors through the uncomplicated LCA application is fostering sustainable design, generative design tools can achieve this.Originality/valueThe novelty of this work is that it is the first initiative offering a parametric LCA tool. It promotes the application of LCA at the design stage using generative design, which contributes to sustainable development.

Construction Education through Virtual Reality: A Game-based Approach for Interior Architecture Students

This study investigates a novel method of instructing interior architecture students on building specifics pertaining to walls by utilizing the combination of virtual reality (VR) and game-based learning. The creation and application of a virtual reality game called "VR ConstructED," which aims to improve knowledge of wall construction methods, materials, and design consequences, is the study's focus. This project intends to improve students' understanding of wall-related construction elements and their applicability in real-world circumstances by utilizing the immersive and interactive properties of virtual reality technology in conjunction with gamification methods. Through a case study involving academic staff and students at Bahçeşehir University, the efficacy of this pedagogical strategy will be assessed. Using a mixed-methods approach, the study collects quantitative data from surveys and qualitative data from semi-structured interviews. These questionnaires will evaluate the academic performance, contentment, and VR game participation of the students. The main goal is to clarify the advantages and difficulties of using virtual VR to teach construction features, such walls, so that curriculum designers and teachers may make informed decisions. Additionally, by illustrating how gamification and the integration of VR technology may greatly improve student engagement and academic achievement, this study hopes to contribute to the larger area of design education. The results of this study are anticipated to add to the body of knowledge in architectural education and stimulate more research into specific VR applications for design pedagogy.