Selection Of Wall Material Research Articles

Encapsulation of Lactobacillus rhamnosus GG in whey protein isolate-shortening oil and gum Arabic by complex coacervation: Enhanced the viability of probiotics during spray drying and storage

The previous study revealed the protective effect of solid fat on probiotics against heat damage during spray drying. However, the simple mixing mode prior to spray drying did not effectively enhance the cooling efficiency of solid fat on probiotics. Therefore, this study aimed to improve the encapsulation efficiency of solid fat for probiotics and reduce the exposure area of probiotics to hot air during spray drying by encapsulating them in coacervates formed by whey protein isolate-high melting point fat shortening oil (SO) and gum arabic through complex coacervation. The combination of fluorescence microscope and scanning electron microscope proved that the coacervates successfully encapsulated the probiotics during spray drying, resulting in an increased survival rate from 24.59% to 54.96% after the process. Differential scanning calorimetry and single droplet drying experiments confirmed that the addition of SO reduced the temperature of microcapsules by increasing the enthalpy of melting during spray drying, without affecting the drying rate. Among the tested formulations, the microcapsules generated by the combination of SO addition and coacervate formation exhibited the lowest water activity, highest cell integrity and growth ability, corresponding to the superior survival of probiotics during storage at 25 °C and 4 °C. In conclusion, the current research has provided valuable insights into the selection of wall materials and pretreatment methods for spray drying of active substances.

Three-Dimensional Numerical Modeling and Analysis for the Municipal Solid-Waste Incineration of the Grate Furnace for Particulate-Matter Generation

A 3D numerical model of the municipal solid waste incineration (MSWI) process was constructed based on a grate furnace with a daily processing capacity of 800 tons. Fluent was used for analyzing key factors affecting the concentration and diffusion level of particulate matter (PM). According to the actual MSWI plant working condition, a 3D model of the incinerator and the waste heat boiler has been constructed under benchmarks. Key factors affecting PM generation were determined by combining mechanistic knowledge and experts’ experience. They were the combustion temperature of solid phase municipal solid waste (MSW), the wall’s PM collision mode, and the second baffle length. Subsequently, the process of resolving the 3D numerical model was delineated. Then, a univariate analysis of the aforementioned 3D model was conducted for the three pivotal factors mentioned above. Conclusively, the effect of the important factors on the number of particles at the outflow of the incinerator was analyzed via orthogonal experiments to obtain the optimal combination. PM concentration initially diminished and then rose with the increased combustion temperature of the solid-phase MSW. Furthermore, a noteworthy reduction in PM concentration was observed when the second baffle length was 12.45–12.95 m. The greatest influence on the PM concentration of the outlet was posed by the wall’s PM collision mode, followed by the second baffle length. The appropriate adjustment of the combustion temperature of the solid-phase MSW, selection of wall materials, and design of the second baffle length were beneficial for diminishing PM concentration and ensuring long-term stable operation of the MSWI process. The combinative optimality of the three key factors was acquired via orthogonal experiments, which proved the subsequent optimal control of PM concentration at the outlet.

A review on the encapsulation of bioactive components using spray‐drying and freeze‐drying techniques

AbstractBioactive compounds are a type of chemical substance found in plant sources. Lycopene, carotenoids, phytochemicals, phenolic compounds, and anthocyanin are a few bioactive compounds. These compounds are rich in antimicrobial, antioxidant, and free radical‐scavenging properties. But these compounds are easily degraded. In order to enhance the chemical stability and the retention properties of functional ingredients, encapsulation is indispensable. This paper reviews the two important methods of encapsulation of bioactive components and the novelties in these techniques. Spray‐drying and freeze‐drying techniques are commonly used for encapsulation in the food and pharmaceutical industries. The former is a quick and high‐temperature process, while the latter is a time‐consuming and low‐temperature procedure. The inlet temperature during spray drying is maintained between 120 and 190°C, whereas during freeze drying, a temperature of −80°C to −20°C is maintained. For effective encapsulation, the optimization of the process conditions such as the temperature, pressure, feed rate, airflow rates, and selection of wall materials are essential. In this paper, the influence of these parameters on encapsulation efficiency and product stability is also discussed.Practical ApplicationsThe spray‐drying and freeze‐drying techniques find their application in the food and chemical industries for the purpose of encapsulation and drying. The former technique helps transform liquid foods to powder and thereby extending their shelf life. The encapsulation of some biologically active components helps better retention and delivery of the components. Spray drying is a technique in which liquid foods are converted to powdered form. These techniques have been used for a very long time in the dairy industry. But in recent times, they have been used in the pharmaceutical industries as well. Their main application in the pharmaceutical industry is drug delivery. Freeze drying is a low‐temperature encapsulation process which is mainly used for the encapsulation of functional foods. The most commonly spray‐dried active materials include oleoresins, natural food colors, natural antioxidants, lipids, flavors, and functional foods. Probiotic sources such as bacterial cultures are the main freeze‐dried products. In this review, the practical applications of the techniques are elaborated.

Nonlinear Behavior of Helmholtz Resonator With a Compliant Wall for Low-Frequency, Broadband Noise Control

Abstract Low-frequency sound attenuation is often pursued using Helmholtz resonators (HRs). The introduction of a compliant wall around the acoustic cavity results in a two degrees-of-freedom (2DOF) system capable of more broadband sound absorption. In this study, we report the amplitude-dependent dynamic response of a compliant-walled HR and investigate the effectiveness of wall compliance to improve the absorption of sound in linear and nonlinear regimes. The acoustic-structure interactions between the conventional HR and the compliant wall result in non-intuitive responses when acted on by nonlinear amplitudes of excitation pressure. This paper formulates and studies a reduced order model to characterize the nonlinear dynamic response of the 2DOF HR with a compliant wall compared to that of a conventional rigid HR. Validated by experimental evidence, the modeling framework facilitates an investigation of strategies to achieve broadband sound attenuation, including by selection of wall material, wall thickness, geometry of the HR, and other parameters readily tuned by system design. The results open up new avenues for the development of efficient acoustic resonators exploiting the deflection of a compliant wall for suppression of extreme noise amplitudes.

ANALISIS ENERGI PADA BERBAGAI MATERIAL DINDING (BATA, BATAKO DAN BATA RINGAN)

In building design, the selection of building materials is one aspect that needs to be considered. Building materials are components that require energy in the manufacturing process. In the process of building material production, the use of energy at each stage becomes one of the parameters of CO2 carbon emission levels. The higher the use of fossil energy, the higher the CO2 emissions and the risk of causing global warming. Bricks, concrete blocks, and lightweight bricks are the types of materials commonly used to make building walls. The selection of wall materials is still largely related to price or aesthetic considerations, but the assessment of the level of environmental friendliness is still lacking in attention. This study tries to analyse the life cycle of energy in wall materials (bricks, concrete blocks and lightweight bricks). From the research results obtained, concrete block is the lowest material in the use of production energy.

Microencapsulation of curcumin by spray drying and freeze drying

Curcumin is a natural pigment with health benefits and potential uses in food and pharmaceutical products, but its application is limited by its insolubility and instability. This study was to examine the effect of spray drying and freeze drying methods, as well as 12 combinations of ternary-composite wall materials, on microencapsulation efficiency (MEE), physicochemical properties (including particle size distribution, morphology, moisture content, and color values), and stability of curcumin against environmental stresses and in a model beverage. Curcumin encapsulated by freeze drying presented higher MEE, whereas spray drying produced microparticles of smaller particle size, smoother granule surface, and more regular shapes. Though to different extent, curcumin encapsulated by both methods exhibited improved stability against heat and acidity, and improved stability in a carbonated beverage. This study provides practical information on the selection of wall materials and encapsulation methods for microencapsulating curcumin for various applications.

How Friendly Are Building Materials as Reflectors to Indoor LOS MIMO Communications?

The tremendous popularity of Internet-of-Things (IoT) applications and wireless devices has prompted a massive increase of indoor wireless traffic. To further explore the potential of indoor IoT wireless networks, creating constructive interactions between indoor wireless transmissions and the built environments becomes necessary. The electromagnetic (EM) wave propagation indoors would be affected by the EM and physical properties of the building material, e.g., its relative permittivity and thickness. In this article, we construct a new multipath channel model by characterizing wall reflection (WR) for an indoor Line-of-Sight (LOS) single-user multiple-input–multiple-output (MIMO) system and derive its ergodic capacity in the closed-form. Based on the analytical results, we define the wireless friendliness of building material based on the spatially averaged indoor capacity and propose a scheme for evaluating the wireless friendliness of building materials. Monte Carlo simulations validate our analytical results and manifest the significant impact of the relative permittivity and thickness of building material on indoor capacity, indicating that the wireless friendliness of building materials should be considered in the planning and optimization of indoor wireless networks. The outcomes of this article would enable appropriate selection of wall materials during building design, thus enhancing the capacity of indoor LOS MIMO communications.

A Fluorescence-based Method for Estimation of Oxygen Barrier Properties of Microspheres.

In this study, we developed a fluorescence method to quantify oxygen barrier properties for wall materials used in microencapsulation of oxygen-sensitive compounds. We used a reversible, oxygen quenching dye, tris (4,7-diphenyl-1, 10-phenanthroline) ruthenium(II) dichloride complex, as a marker to monitor oxygen transport across spray-dried and freeze-dried Hi-cap100 and maltodextrin microspheres. We fit the rate of oxygen transport to Fick's second law and extrapolated an effective oxygen diffusion coefficient Deff. Results show that the Deff for spray-dried maltodextrin and Hi-cap100 formulations were in the range of 6.46 × 10-15 to 7.45 × 10-15 m2 /s and 16.0 × 10-15 to 22.4 × 10-15 m2 /s, respectively. Results also show an increasing trend in thiobarbituric acid reactive substances reaction rate constants, with an increasing Deff for each formulation. Additionally, freeze-dried maltodextrin formulations had significantly higher Deff (31.1 × 10-15 to 36.0 × 10-15 m2 /s) compared to spray-dried matrices due to a more porous morphology. This new method provides a framework for the in situ estimation of Deff for wall materials in microspheres. Potential applications include the design and selection of wall materials for maximum oxidative stability of encapsulated ingredients. PRACTICAL APPLICATION: Currently, the selection of wall materials used in microencapsulation of lipids takes a trial-and-error approach, which can be time consuming and prone to error. In this study, we developed a new methodology to directly assess the oxygen barrier properties of wall materials in microspheres. This method can be used by food scientists to screen wall materials in order to optimize the oxidative stability of encapsulated lipids.

A Model Proposal for Wall Material Selection Decisions by Using Analytic Hierarchy Process (AHP)

A Model Proposal for Wall Material Selection Decisions by Using Analytic Hierarchy Process (AHP)

A Model Proposal for Wall Material Selection Decisions by Using Analytic Hierarchy Process (AHP)

A Model Proposal for Wall Material Selection Decisions by Using Analytic Hierarchy Process (AHP)

Improving the energy storage capability of hot water tanks through wall material specification

Domestic hot water tanks represent a significant potential demand side management asset within energy systems. To operate effectively as energy storage devices, it is crucial that a stratified temperature distribution is maintained during operation; this paper details experimental and numerical work conducted to understand the influence that wall material specification has on de-stratification within domestic hot water tanks. A 2d axisymmetric CFD (Computational Fluid Dynamic) model was consistent with experiments which showed that switching from copper to stainless steel resulted in a 2.7 fold reduction in useable hot water loss through reduced de-stratification for a 74 L UK domestic hot water tank over a 48 h period. During simulation, a counter rotating convection system, with peak velocities of 0.005 m/s, was observed above and below the thermocline. Minimizing de-stratification, through appropriate wall material selection, increases the performance of hot water tanks and scope for their use in demand side management applications. Given the inconclusive evidence surrounding copper's efficacy as a sanitizing agent, along with the low tensile strength of polyethylene, this paper advocates the use of stainless steel in hot water tank walls and further exploration of alternative materials and composites which have low cost and low thermal conductivity along with high strength and manufacturability.

Mixture Design Approach in Wall Material Selection and Evaluation of Ultrasonic Emulsification in Flaxseed Oil Microencapsulation

Flaxseed oil, sensitive to oxidation, was systematically microencapsulated with six triple wall materials combinations [carbohydrate (maltodextrine and two different modified starches (N-Lok® and HiCap® 100)); protein (sodium caseinate, whey protein concentrate); and Arabic gum] for the highest microencapsulation efficiency and oxidation stability. Proportions of the triple wall materials were optimized in mixture design using the quadratic model. Effects of Ultra-Turrax and ultrasonic emulsifications on microencapsulation efficiencies were additionally characterized in the optimized wall material combinations. The microcapsules produced were investigated for particle size distribution, moisture content, water activity, bulk density, and oxidative stability. Results showed that the combination of modified starch (Hi-Cap® 100)/Arabic gum/whey protein concentrate (4/0/1, w/w/w) provided the highest efficiency in flaxseed oil microencapsulation. However, the only successful combination in preventing flaxseed oil oxidation was maltodextrine/Arabic gum/whey protein concentrate (4/0/1, w/w/w). The microcapsules produced by ultrasonic emulsification had higher microencapsulation efficiency than that of Ultra-Turrax emulsification.

Wall Material Selection for Encapsulation by Spray Drying

Wall Material Selection for Encapsulation by Spray Drying

Characteristics of Single Droplet Impact on Cold Plate Surfaces

Droplet collision with cold solid surfaces is a fundamental phenomenon observed in low-temperature processes. In this work, a single droplet impacting on a cold surface was investigated by analyzing changes in droplet shape and dimensions recorded with a high-speed camera. At low surface temperatures (−5°C and −10°C), the droplet spreads in a very short period upon impact and then retracts, but to a diameter larger than that at room temperature, dependent on surface material property and texture. Higher impact velocity expands the spreading diameter and promotes the retraction to an extent, but at lower surface temperature (i.e., −20°C) the droplet is quickly frozen with smaller change in diameter on the stainless-steel surface rather than on the Teflon plate. The change of droplet shape upon impacting on a 30° inclined surface was also studied. The surface texture of the stainless-steel plate produced by the polishing process has an obvious effect on the droplet dimension retraction. A proper selection of wall material and process conditions can alleviate or prevent wall deposition.

The Lithium Wall Stellarator Experiment in TJ-II

In the last years, lithium wall conditioning has been carried out in several fusion devices by different techniques, providing in many instances record values of plasma parameters and enhanced plasma reproducibility and opening the possibility of developing high radiative, low recycling liquid divertor concepts of high potential for future reactors. This concept has been termed the Li Tokamak Reactor. Compared to tokamaks, stellarator plasmas show distinct features in their interaction with the surrounding materials. The lack of disruptions and type I ELMs make them more reliable for reactor operation. So it is the lack of MHD-driven density limit. On the other side, the intrinsic radiative character of the density limit of stellarators and the tendency to central impurity accumulation makes wall-material selection paramount. In the present work, the plasma performance of the TJ-II Heliac under Li-coated wall conditions is described. Compared to previous coatings, lithium has produced the best plasma performance to date, leading to the achievement of record values in plasma density and energy confinement. Plasma profiles free from impurity accumulation have been obtained under specific fuelling schemes. Future research lines in this direction, with impact on the design of a Li stellarator reactor concept, are also addressed.

Unique Microcapsule Toner Synthesized by Liquid Phase Separation

The specific design of microcapsules by liquid‐phase separation on organic solvents is enabled using a method for the selection of wall materials and solvents based on solubility parameters and, finally, molecular structures of raw material candidates. The feasibility of the method is demonstrated by the fabrication of a microcapsule toner called “curlfit toner”, whose superior surface coverage properties over conventional toners are demonstrated by enlargements juxtaposed in the Figure.

Enhancement of H − production in a multicusp source by proper selection of wall material

The effect of the wall material on hydrogen ion species productions in a low-pressure plasma, especially H − ions, is studied experimentally by using a multicusp ion source. Under the same discharge conditions, Al generally produces the highest H − ion current although the difference in H − yield between Al, Cu and stainless-steel liners depends on the source pressure of hydrogen gas. At the same time, there is little difference in the plasma parameters for the three different metal liners. The present results suggest that neutral particles (i.e. atomic hydrogen (H) and vibrationally excited molecules (H ∗ 2))-wall interaction affects those differences in H − production.

A Scanning Electron Microscopy Study of Microencapsulation

ABSTRACTScanning Electron Microscopy (SEM) has been applied to the morphological study of various microcapsule systems. In addition to using standard preparation techniques for the examination of the outer structure of microcapsules, a new embedding and microtoming technique has been developed to allow the study of the inner structure of fractured capsules. The technique uses a new nonpolar embedding resin, Lowicryl HM‐20, which is compatible with the microcapsule shell material, and does not introduce artifacts associated with the use of epoxy resins. We demonstrate the potential of SEM techniques as a tool for selection of wall materials, for the study of core materials distribution in microcapsules, and for elucidating the mechanisms of capsule formation and the effects of water‐vapor uptake on microcapsule properties.