Wall Surface Material Research Articles

Laboratory testing on cracking characteristics and improvement mechanism of coral mud

In recent years, the development and construction of island reefs have been flourishing. Due to the remoteness of island reefs from the mainland, the scarcity of building materials, and the high transportation costs, it is imperative to use local marine resources, and the potential value and status of coral mud on island reefs, which is formed by the remains of corals and other biological entities, is becoming increasingly prominent. Utilization and optimization of natural resources on island reefs have become a brand-new research direction and challenge. This article mainly focuses on the development of a new type of green engineering material, coral mud, for use in building surface layers. Thickness effects, PVA fiber (vinylon staple fiber) modification, and HPMC (Hydroxypropyl Methyl Cellulose) adhesive modification are taken into consideration. Through laboratory tests and image processing technology, fractal theory, and electron microscopy experiments, the macro-meso-microscopic multi-scale cracking rules of the coral mud surface layer and the optimization modification rules of PVA fibers and HPMC adhesives are revealed. The results demonstrate that the performance of the coral mud surface layer is superior to that of the kaolin surface layer, and the 10 mm thickness performs better than the 5 mm and 20 mm thicknesses. As the thickness of the coral mud surface layer increases, the contact between coral mud particles becomes denser, the scale of surface micro-cracks decreases, and the number of micro-pores decreases. PVA fibers can effectively inhibit the further development of macro and micro cracks and play a good bridging role. There is a bonding and adhesion relationship between coral mud and PVA fibers, and they have a good synergistic effect in inhibiting macro and mesoscopic cracks. With the increase in HPMC adhesive content, the number of micro-cracks and the scale of micro-cracks decrease accordingly, and the structure and performance of the coral mud surface layer are further improved. Overall, PVA fibers are more effective than HPMC adhesives in inhibiting the cracking of the coral mud surface layer. This provides valuable guidance for the development and application of coral mud in wall surface materials.

Design of coupled Helmholtz resonator with rectangular enclosure to mitigate low frequency noise in recording booths

This study summarizes theoretical and experimental findings for low frequency noise mitigation in small recording booths using coupled Helmholtz resonators. The room acoustical resonance modes were identified using ANSYS simulation software for the recording booth. An experimental setup validated the existence of the different low frequency modes and variation from theoretical results due to the enclosure wall's surface material. Microphone and speaker system were used to measure the room frequency response at the resonant frequencies. Piezoelectric sensors were placed at different positions within the room to determine the location of resonance peaks and the optimized position for the coupled Helmholtz resonator. The effects of damping on the Helmholtz resonator frequency response and deviation from theoretical design formulae were explored. The resonator apparatus proved to attenuate noise to half as loud in the selected low frequency range within the recording booth.

Design analysis of electro-adhesive mechanism for wall-climbing robot

Electro-adhesive mechanism (EAM) has recently been considered for research studies to be used in a wall-climbing robot. The EAM has the advantage over other adhesion mechanisms due to its suitability to work on various wall surface materials. The main challenges associated with the electro-adhesion are achieving high payload, precise fabrication and integration with the robot locomotion. In the present work, electro-adhesive mechanisms have been considered for analysis, simulation and experimental validation under different design parameters for their suitability in the wall-climbing robot. Design parameters such as shape of the electrode, insulating material and high input voltage for the EAM have been evaluated from the analytical model and finite element model using EMWorks software. These studies show that the different design parameters have a major influence on the generated adhesion force. Simulation and experimental studies have been done for the comparison of two cases, namely simple and comb shape electrode pair design with different insulating materials. The results show that the comb shape electrode pair design of the electro-adhesion mechanism exhibits more adhesion force as compared to the simple electrode pair design. The study also suggests low thickness with high relative permittivity material of the insulating layer can be preferred for the design of the mechanism. An analytical study has been carried out for the suitability of EAM application for wall-climbing robots.

Modelling and Simulation of Multiphase Flow Applicable to Processes in Oil and Gas Industry

Abstract Solid particle erosion is a mechanical process of destroying a wall surface material due to the impacts of solid particles entrained with a fluid. It is a frequent phenomenon encountered within various industries such as chemical processes, oil and gas, and hydraulic transportation. Erosion problem has led to enormous consequences such as oil spills caused by equipment failure of oil transmission pipelines, chokes valves, pipe fittings etc; resulting in considerable economic loss as well as safety and environmental concerns. In this study, a 3-D simulations are performed using CFD code ANSYS FLUENT to predict sand erosion rates under different engine-oil viscosity conditions for multiphase liquid, in a 90-degree standard (R/D = 1.5) elbow pipe. The CFD utilizes Eulerian-Lagrangian method to model the multiphase flow oil-water-sand in elbow. The realizable k-ε model is adopted for the fluid turbulence effects. The velocity and pressure distributions are analysed as contours for the fluid flow. In order to understand the dynamics of the erosion process, the motion of the solid particles are also investigated based on Stokes number as well as the effect of secondary flows. The results indicated that erosion rates decrease with the increase in oil viscosity. Additionally, erosion mainly occurs in two locations; at the extrados near the bend exit and also on the side walls of the downstream straight pipe. The unusual distribution of erosion on the side walls occurred as a result of the effect of secondary flows due to centrifugal force. The numerical results are in qualitative good agreement with the experimental data available in the literature for elbows in order to validate the presented modelling approach.

Wall chemical effect of metal surfaces on DME/air cool flame in a micro flow reactor

Wall chemical effect on DME/air weak flames (Uin = 1.5 cm/s, ϕ = 0.85) was investigated using a micro flow reactor with a streamwise temperature gradient experimentally. The quartz channel used in this study has a rectangular cross-section of 1.5 × 5 mm, which offers a good optical access for the planar laser-induced fluorescence (PLIF) measurement. The walls can be replaced for examining wall chemical effects of different wall materials. Wall surface materials, quartz, SiC, type 321 stainless steel (SUS321), iron, nickel and chromium, were employed. For SiC, SUS321 and metals, a 150-nm-thick film is deposited on the inner surface of the quartz channel to achieve different wall chemical boundary with identical thermal boundary condition. Streamwise distributions of DME, CO and CO2 in the weak flame were measured with the gas chromatography (GC), and HCHO and OH distributions were measured through PLIF. It is found that species distributions in both the low- and high-temperature oxidation zones of the weak flame are significantly altered for different wall surface materials. Comparing with that in the quartz and SiC-coated channel, DME in the SUS321-coated channel has a much higher concentration in the negative temperature coefficient (NTC) region, while CO and HCHO have lower concentrations. The peak of OH is shifted downstream, and so as the rising of CO2. According to the results of the pure metal-coated channels, iron and nickel in the SUS321 should be responsible for the changes. These results suggest that the wall chemical effect of metal may exert strong influence on the low-temperature oxidation, which changes the species pool in the cool flame and leads to a modification of the hot flame region downstream.

Fashion retail store facades and the creation of store image and store attitude

Successful use of displays in stores arouses consumers' curiosity, and induces them to purchase a product after a visit. Facade is a word meaning an external front wall of a building, and is usually the first point of visual contact for the consumers. The present study is an empirical investigation of external appearance of a clothing store, with a factorial design of facade, show window, and wall surface material designed for the purpose of the study. Dependent variables were store image variables and attitude toward store. A total of 320 questionnaires from male and female consumers were used for the analysis. Facade type and material had significant main and interaction effects, while show window type had no meaningful effects overall. A facade of irregular design prompted significantly higher levels of perceived 'elegance', 'uniqueness', and 'attractiveness' of the store. Material itself did not have significant influence but did have significant interaction effect with facade design. The interaction effect was found in store attitude as well. In order to create a positive store attitude, a concrete material facade should have an irregular design. Companies owning fashion brands should carefully select facade type and wall surface material in the visual merchandising strategies of a store.

Influence of Surface Emissivity on the Heat Loss through the Wall Behind the Heater

The paper presents a solution to a problem of heat transfer through the external wall region behind the heater, which is actively warming up and through which additional heat loses occur. Author developed a method for temperature calculations on the inner surface of the external wall region behind the heater, that takes into account inner wall surface material reflection coefficient. According to the author's conducted calculations it is possible to show, that due to application of a baffle, made of aluminum foil with low emission coefficient, temperature of the wall surface behind the heater declines as well as the heat loses through this part of the wall. Calculations made by proposed method allows us to estimate efficiency of materials with low surface emission coefficient application in the exterior walls.

Investigation of Noise Reduction Coefficient of Organic Material as Indoor Noise Reduction Panel

Noise can cause a few types of effect to human health especially in hearing like hearing loss. Indoor noise pollution comes from many sources and places. The research focuses on the sound reduction wall surface material rather than any techniques available and using organic material like coconut coir fiber, rice husk and sawdust. These sound reduction material is suitable to apply as interior lining for homes and offices. This research conducted to compare the efficiency of coconut coir fiber, rice husk and sawdust as indoor noise reduction, to evaluate the effectiveness indoor noise level by using wall surface sound reducer material and to determine the best material that will reduce noise level. In preparation of board panel, two binders were used which is polyester resin and hardening catalyst, cement and sand. For board panel using binder of polyester resin and hardening catalyst, the binders were stirred for two minutes. Then, the mixture of polyester resin, hardening catalyst with raw material was mix uniformly. The suppression done for 24 hours in order to obtain a composite outcome that is denser. Then, the ratio for coconut coir fiber, cement and sand is 1.5:0.5:0.5, the same ratio used for sawdust and rice husk and the Noise Reduction Coefficient (NRC) will be determined. The parameter use to determine the NRC and the sound transmission are the frequency, speaker intensity and the distance from the speaker. If not absorbed, the sound can be reflected and this will prevent sound dispersed to other space. The results show rice husk is better with cement binder and sand, while for polyester resin and hardening catalyst binder, sawdust is the best. Therefore, currently organic materials present good alternative to synthetic material providing good health with green environment as well as enhancing natural agricultural and growth.

Research on Design Development of Eco-friendly Interior Finishing Materials - Focused on wall surface materials using Korean paper -

Research on Design Development of Eco-friendly Interior Finishing Materials - Focused on wall surface materials using Korean paper -

MNM-5B-4 マイクロ流路内予混合火炎における化学的壁面効果に関する研究(セッション 5B マイクロエネルギー)

Measurement of quenching distance for different wall temperature and surface material is conducted in parallel quartz plates with metal coating. It is found that quenching distance is decreased with increasing wall temperature, showing the wall thermal effect on flame quenching. Quenching distance become slightly larger between Cr-coated plates, thus the wall chemical effect does exist. In addition, phase-locked OH-PLIF measurement has been developed for investigation of detailed quenching mechanism of the oscillating flame in a planar micro channel.

Urban river wall habitat and vegetation: observations from the River Thames through central London

Along heavily engineered urban rivers, river walls and embankments represent the most common habitat available to riparian vegetation. This paper presents the first study into river wall vegetation and the influence of wall surface materials on plant diversity. We were concerned with investigating the plant diversity of such wall habitats, assessing relationships between different wall surface materials and plant diversity, and determining whether river wall and embankment habitats along the River Thames through central London could support native riparian species alongside more typical urban wall flora. Fifteen sites along the River Thames through central London were surveyed to describe wall flora and establish relationships between plant diversity and wall materials. Walls were not species rich, but contained a mix of terrestrial and riparian species. Stone walls with surface fractures and heterogeneous wall surfaces were conducive to plant diversity at the local scale, while wall surface heterogeneity was also important at the landscape scale. Some stratification of vegetation was observed based on wall position relative to flow disturbance. The potential exists for walls to act as sites for habitat improvement and reconciliation ecology within urban rivers.

Depletion of 1-MCP by ‘non-target’ materials from fruit storage facilities

The sorption of 1-methylcyclopropene (1-MCP) by a number of ‘non-target’ materials found in apple ( Malus × domestica Borkh.) and pear ( Pyrus communis L.) fruit storages was measured as a function of time, temperature, and moisture content. Materials included bin construction materials [high density polyethylene (HDPE), polypropylene (PP), extensively- and slightly-weathered oak ( Quercus sp.), weathered fir ( Abies sp.) plywood, and cardboard] and wall surface materials (polyurethane foam and cellulose-based fire retardant). Bin construction materials test pieces had an external surface area of 180 cm 2. We placed ‘non-target’ materials in 1-l glass jars and added 1-MCP gas to the headspace at an initial concentration of approximately 30 μl l −1. Gas concentrations were measured after 2, 4, 6, 8, 10, and 24 h. The concentration of 1-MCP in empty jars was stable for the 24-h holding period. There was little to no sorption by HDPE, PP, polyurethane foam, or fire retardant. However, plywood, cardboard, slightly-weathered oak, and extensively-weathered oak absorbed 16, 18, 55, and 75% of the 1-MCP after 24 h. Moistening the test material increased the rate of sorption of 1-MCP for cardboard, plywood, weathered oak, and non-weathered oak, resulting in a depletion of approximately 98, 70, 98, and 98%, respectively, in 24 h. For oak bin material, the rate of sorption was not impacted by temperature and increasing the surface area by approximately 100% only marginally increased the rate of sorption. When moistened oak bin material was included with apple fruit in a proportion similar to that found in fruit storage, 90% depletion occurred in 6 h compared to approximately 80% in 24 h for fruit alone. The data suggest that 1-MCP levels can be compromised by wooden and cardboard bin and bin liner materials, but not by plastic bin materials or wall surface materials commonly used in Michigan.

Effect of wall surface materials on deposition of particles with the aid of negative air ions

This work studied how wall surface materials influence the removal of airborne particles with negative air ions (NAIs) in indoor environments. Five wall surface materials—stainless steel, wood, PVC (polyvinyl chloride), wallpaper and cement paint—were applied to the inner surface of a test chamber. Two monodispersed solid NaCl particle sizes, 300 and 30 nm, were tested. The NAIs in the chamber were generated by negatively electric discharge in the range 3000–5000 ions cm - 3 . Experiments on the natural decay and application of NAIs were conducted at an air exchange rate of 1 h - 1 . The decay coefficient, the removal efficiency, the time to halve the concentration ( T 50 ) and the effective cleaning rate (ECR) were taken into account. The experimental data revealed that NAIs enhanced the removal of both 300 and 30 nm particles for each wall surface material. The decay coefficients of the NAI applications ( k a ) were 2.9–7.4 and 2.5–4.0 times higher than those of natural decay ( k n ) for 300 and 30 nm particles, respectively. However, the effect of the wall surfaces on the removal of particles was observed in both natural decay and NAI application experiments. The order of natural decay for 300 and 30 nm particles under different wall surfaces was cement paint > PVC ≅ wallpaper ≅ wood > stainless steel, as perhaps determined by the roughness of the wall materials. The overall removal efficiencies of 300 and 30 nm particles during 30 min of NAI emission were over 60% and 80%, respectively, in the chamber with wood and PVC wall surfaces. The half concentration times ( T 50 ) of NAI applications for various wall surfaces were less than 20 min, except for stainless steel and cement paint walls. The ECR demonstrated that the net effects of the NAIs for 300 nm particles followed the order wood (34.6 Lpm) > PVC (33.3 Lpm) > wallpaper (27.0 Lpm) > stainless steel (16.6 Lpm) > cement paint (14.8 Lpm). The ECR for 30 nm particles followed the order wood (41.4 Lpm) > PVC (30.4 Lpm) ≅ cement paint (30.3 Lpm) > wallpaper (27.7 Lpm) > stainless steel (20.1 Lpm). The NAI could remove particles from the wood and PVC wall surfaces substantially more effectively than from other wall materials. The various electrical characteristics and roughness of the wall materials may have been responsible for the associated of the various ECRs with the various wall surface materials.

Solid State NMR Studies on Inhomogeneous Structure of Fibre Wall in Kraft Pulp

Summary Solid state NMR spectroscopy was used to analyse the inhomogeneous structure of kraft fibre. Primary fines, isolated from the original kraft pulp, and secondary fines, isolated after refining, were compared with the corresponding long fibres. To fractionate fibre wall surface material, the kraft pulp was refined in stages. After each stage, the secondary fines and long fibres were separated and the long fibres refined again to peel off the surface material. It was found that the crystallinity of cellulose is lower in fines compared with the corresponding long fibres. When the fines fractions were compared with each other, the cellulose crystallinity was observed to increase towards the inner parts of the fibre surface. A very clear gradient was also seen in the amount of extractives, which was highest in the primary fines rich in ray cells. The contents of lignin and some hemicelluloses, mainly xylan and glucomannan, were also higher in fines. Residual lignin isolated from the fines was found to be slightly more condensed than residual lignin from long fibres.

千鳥配置で施工されたジオグリッド急勾配補強土壁施工事例紹介

The use of geogrid steep-slope reinforced earth walls constructed using steel wall-surface material in road embankment work, is spreading rapidly. In Japan, more than 1, 000 such works have been executed with the reinforcement material (geogrid) arranged in a zigzag pattern. No significant deformation has been caused by the use of the zigzag pattern. This pattern enables all wall-surface material to be connected to the main reinforcement material (geogrid). This allows rational design and execution by eliminating the need for wall-surface stabilization reinforcement. This report contains the following information: ·Explanation of the zigzag pattern·Introduction of a design and an execution case

防護柵に作用する水平荷重がジオグリッド急勾配補強土壁に与える影響調査

The use of Geogrid steep-slope reinforced earth walls constructed using steel wall-surface material in road embankment work is spreading rapidly. However, many aspects of the installation of a guard rail in work of this kind are still not clearly understood. This paper introduces the results of a field test on a full-size embankment performed as a first step in making these points clear.The purpose of this experiment are as follows:(1) To study the effects of the installation of a guard rail on a Geogrid steep-slope reinforced earth wall(2) To study the effects of the installation of a guard rail on the GeogridTherefore, the following items were included in the experiment:(1) Measurement of the displacement of the reinforced earth wall and of the change in the horizontal earth pressure of the embankment when a static load and a dynamic load are applied to the guard rail(2) Measurement of the strain distribution of the reinforcing material when a static load is applied to the guard rail(3) Measurement of the state of the reinforcing material, and guard rail damage when a static load and a dynamic load are applied to the guard rail

天然ゼオライトを用いた呼吸性壁面材の使用評価 : 天然ゼオライトを用いた呼吸性壁面材の開発に関する研究 1

天然ゼオライトを用いた呼吸性壁面材の使用評価 : 天然ゼオライトを用いた呼吸性壁面材の開発に関する研究 1

A comparative evaluation with respect to the bacterial cleanability of a range of wall and floor surface materials used in the food industry

J. H. TAYLOR AND J. T. HOLAH. 1996. A range of floor and wall materials suitable for use in the food industry were selected for comparative bacterial cleanability tests. A standard cleaning regime was carried out on samples after biofilm development of Acinetobacter calcoaceticus (CRA 296). Cleanability was measured as the log reduction in bacterial numbers. The results for the wall materials showed that there were no statistical differences, whilst those for the floor materials were more variable. The grouted joints and texture did not compromise the cleanabilities of tiled surfaces.

Structural loads on bunker silo walls: Numerical study

The finite element method (FEM) of analysis was used to investigate wall pressures exerted by silage on bunker silo walls. Normal wall pressures determined by FEM analysis were in very good agreement with experimental values obtained in a field experiment on a large bunker silo. Both experimental and numerical results show that silage pressure increases linearly with depth and that an equivalent liquid pressure formula can be used for prediction. The density of the equivalent liquid can be calculated as the product of the silage bulk density and the pressure ratio (the ratio of the normal to vertical pressure). The pressure ratio is dependent on wall slope, silage surcharge angle and friction angle between wall surface and silage material. The pressure ratio increases by about 45% when the wall slope changes from 90 to 75 °, and by as much as 70% when the surcharge angle changes from 0 to 20 °. It is recommended that both the surcharge angle and the wall slope be taken into account in the design of bunker silos. Wall-silage friction reduces the pressure ratio by about 10% when the coefficient of friction increases from zero to 0·4. The effect of wall-silage friction is therefore of less importance in design calculations.

Transfer processes when the surface material of a body and an injected material react with a laminar boundary layer

The article constitutes an analytical investigation of an unsteady (due to a change in the boundary of the porous body) laminar boundary layer. There is a chemical reaction (for infinitely large rates of heterogeneous and homogeneous reactions) between the wall surface material together with the injected material and a coolant contained in the external flow. For the particular case Pr=Sci=1, a solution in closed form is obtained for problem (31)-(32).