Parameter analysis and modification of transmission loss models for multi-layered cavity walls

2021 ◽  
pp. 1351010X2098735
Author(s):  
Yaw-Shyan Tsay ◽  
Chuan-Hsuan Lin
Keyword(s):  
Transmission Loss ◽  
Attenuation Factor ◽  
Single Layer ◽  
Theoretical Models ◽  
Parameter Analysis ◽  
Cavity Wall ◽  
Predictive Capability ◽  
Proposed Model ◽  
Loss Models ◽  
Steel Stud

Multi-layer cavity wall (MCW) systems, which refer to each panel in the structure being made up of two or more layers of lightweight board, have become more widely used. However, unlike the detailed approaches that were available for predicting single-layer cavity walls (SCW), few studies have addressed the MCW involving different layers attached together. In this research, we applied two theoretical models of SCW, analyzed the key parameters and modify to have appropriate application for MCW. The predictive capability of the models was then evaluated by comparing them with results of experiment and commercial software. The results showed that Sharp’s model was suggested only when the thickness of the steel stud of about 0.75 mm. Through modifying the input values of the compliance of steel ( CM), attenuation factor ( F) and the limiting angle of incident (θ L) in Davy’s model, and the prediction of the proposed model showed great consistent with experiments.

Technical textiles for protection against Arc-flash fire: Savesplash®

2020 ◽  
pp. 67-78
Author(s):  
Nandan Kumar ◽  
Sainath Shrikant Pawaskar
Keyword(s):  
Attenuation Factor ◽  
Threshold Energy ◽  
Single Layer ◽  
Weather Conditions ◽  
Electric Arc ◽  
Risk Category ◽  
Technical Textiles ◽  
Flash Fire ◽  
Level 3 ◽  
Arc Flash

Flash fire caused by electric arc is different than that caused by flammable liquids/fumes or combustible dusts. A suitable protective clothing for protection against electric arc-flash must be designed as per Indian weather conditions. Currently available garments are manufactured using two or three layers of woven/nonwoven combinations to achieve higher Hazard Risk Category (HRC) rating (level 3 and above). However, they are heavy and not comfortable to the end users. Savesplash® is a single layer inherent flame-retardant knitted fabric. Its arc rating was determined using ASTM standards. It achieved arc thermal performance value (ATPV) of 41 cal/cm2, breakopen threshold energy (E_BT) of 42 cal/cm2 and heat attenuation factor (HAF) of 94% when tested as per ASTM F1959/F1959M-14 which translated into an arc rating of 41 cal/cm2. This is equivalent to HRC level 4 ratings as per National Fire Protection Association’s NFPA 70E standard (USA). Further, cut and sewn gloves (HM-100) developed using Savesplash® fabric reinforced with leather on palm area achieved ATPV of 63 cal/cm2 and HAF of 94.5% when tested as per ASTM F2675/F2675M-13.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Analysis of the transmission loss of double-leaf panels with an equivalent spring–mass model for studs

2020 ◽  
Vol 37 ◽  
pp. 126-133
Author(s):  
Yuan-Wei Li ◽  
Chao-Nan Wang
Keyword(s):  
Distribution Curve ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Experimental Results ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Mass Model ◽  
Steel Stud ◽  
Panel Thickness ◽  
Stiffness Distribution

Abstract The purpose of this study was to investigate the sound insulation of double-leaf panels. In practice, double-leaf panels require a stud between two surface panels. To simplify the analysis, a stud was modeled as a spring and mass. Studies have indicated that the stiffness of the equivalent spring is not a constant and varies with the frequency of sound. Therefore, a frequency-dependent stiffness curve was used to model the effect of the stud to analyze the sound insulation of a double-leaf panel. First, the sound transmission loss of a panel reported by Halliwell was used to fit the results of this study to determine the stiffness of the distribution curve. With this stiffness distribution of steel stud, some previous proposed panels are also analyzed and are compared to the experimental results in the literature. The agreement is good. Finally, the effects of parameters, such as the thickness and density of the panel, thickness of the stud and spacing of the stud, on the sound insulation of double-leaf panels were analyzed.

scholarly journals An Empirical Study of S-commerce Adoption on WeChat Platform

2020 ◽  
Vol 5 (3) ◽  
pp. 80
Author(s):  
Mei Ge ◽  
Zhongping Deng ◽  
Jing He
Keyword(s):  
Empirical Study ◽  
Behavioral Intention ◽  
Online Survey ◽  
Theoretical Models ◽  
Utaut Model ◽  
Performance Expectancy ◽  
Proposed Model ◽  
Effort Expectancy ◽  
Pls Analysis ◽  
And Performance

<p>The purpose of this paper is empirically to examine two theoretical models in the context of social electronic commerce (s-commerce). The study tries to extend TAM and UTAUT model with trust to explain consumer behavior in the acceptance of s-commerce on WeChat platform which is the Chinese largest social platform. Through an online survey, 501 valid respondents were collected. A Partial Least Squares (PLS) analysis was used to conduct the proposed model and hypothesis testing with TAM and UTAUT models. The results revealed that trust is the most significant factor affecting behavioral intention and the second significant factor is effort expectancy, then social influence and performance expectancy. The integration of trust factor into the UTAUT model best interprets the adoption of s-commerce among the pure TAM and UTAUT models and extended models with trust. It will provide guidance for marketers and professionals, especially in China.</p>

scholarly journals Comparasion of prediction and measurement methods for sound insulation of lightweight partitions

2012 ◽  
Vol 10 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Momir Prascevic ◽  
Dragan Cvetkovic ◽  
Darko Mihajlov
Keyword(s):  
Transmission Loss ◽  
Road Traffic ◽  
Theoretical Models ◽  
Measurement Methods ◽  
Experimental Results ◽  
Sound Insulation ◽  
Acoustic Absorption ◽  
Noise Levels ◽  
Overall Design ◽  
Acoustic Comfort

It is important to know the sound insulation of partitions in order to be able to compare different constructions, calculate acoustic comfort in apartments or noise levels from outdoor sources such as road traffic, and find engineer optimum solutions to noise problems. The use of lightweight partitions as party walls between dwellings has become common because sound insulation requirements can be achieved with low overall surface weights. However, they need greater skill to design and construct, because the overall design is much more complex. It is also more difficult to predict and measure of sound transmission loss of lightweight partitions. There are various methods for predicting and measuring sound insulation of partitions and some of them will be described in this paper. Also, this paper presents a comparison of experimental results of the sound insulation of lightweight partitions with results obtained using different theoretical models for single homogenous panels and double panels with and without acoustic absorption in the cavity between the panels.

scholarly journals A Trans-Scale Young’ Modulus Calculation Model of ITZ Based on Void Shape Randomness and Calcium Hydroxide Enrichment

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Junqing Liu ◽  
Fan Zuo ◽  
Chao Liu
Keyword(s):  
Calcium Hydroxide ◽  
Random Distribution ◽  
Young Modulus ◽  
Theoretical Models ◽  
Calculation Model ◽  
Interfacial Transition Zone ◽  
Morphological Parameters ◽  
Proposed Model ◽  
Three Phase ◽  
Void Shape

The randomness of void shape and enrichment of calcium hydroxide are significant in interfacial transition zone (ITZ) of concrete; however, current theoretical models of ITZ do not include these features. In this article, ITZ was regarded as a three-phase composite material, and the pore morphological parameters were defined according to the characteristics of microscopic pores, and the corresponding random distribution function was constructed. The calcium hydroxide enrichment factor was introduced, and a cross-scale ITZ Young’s modulus calculation model was established in combination with the Mori–Tanaka method. The reliability of the proposed model in this paper was verified through comparison to experimental results in a reference.

scholarly journals Numerical and Theoretical Models for NFRCM-Strengthened Masonry

2019 ◽  
Vol 817 ◽  
pp. 44-49
Author(s):  
Claudia Brito de Carvalho Bello ◽  
Daniele Baraldi ◽  
Giosuè Boscato ◽  
Antonella Cecchi ◽  
Olimpia Mazzarella ◽  
...  
Keyword(s):  
Parametric Analysis ◽  
Numerical Models ◽  
Pushover Analysis ◽  
Single Layer ◽  
Theoretical Models ◽  
Layer Model ◽  
Cementitious Matrix ◽  
Reinforced Masonry ◽  
Homogenized Model ◽  
Fabric Reinforced Cementitious Matrix

The shear behavior of masonry strengthened with natural fabric-reinforced cementitious matrix (NFRCM-strengthened masonry) is investigated through two different numerical models: a multi-layer model considering masonry and reinforcement as different materials and a multi-step homogenized model, where reinforced masonry is considered as a whole. The approaches are compared by performing nonlinear numerical pushover analysis with an increasing shear action applied to the panels. The parametric analysis shows the capacity and limits of both continuous diffused models – defined as a multi-or a single layer - to represent reinforced masonry in-plane behavior.

A physically based model for the electrical conductivity of partially saturated porous media

2020 ◽  
Vol 223 (2) ◽  
pp. 993-1006
Author(s):  
Luong Duy Thanh ◽  
Damien Jougnot ◽  
Phan Van Do ◽  
Nguyen Van Nghia A ◽  
Vu Phi Tuyen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Porous Media ◽  
Fractal Dimension ◽  
Water Saturation ◽  
Theoretical Models ◽  
Fluid Composition ◽  
Physically Based Model ◽  
Partially Saturated ◽  
Proposed Model ◽  
Physically Based

SUMMARY In reservoir and environmental studies, the geological material characterization is often done by measuring its electrical conductivity. Its main interest is due to its sensitivity to physical properties of porous media (i.e. structure, water content, or fluid composition). Its quantitative use therefore depends on the efficiency of the theoretical models to link them. In this study, we develop a new physically based model that takes into account the surface conductivity for estimating electrical conductivity of porous media under partially saturated conditions. The proposed model is expressed in terms of electrical conductivity of the pore fluid, water saturation, critical water saturation and microstructural parameters such as the minimum and maximum pore/capillary radii, the pore fractal dimension, the tortuosity fractal dimension and the porosity. Factors influencing the electrical conductivity in porous media are also analysed. From the proposed model, we obtain an expression for the relative electrical conductivity that is consistent with other models in literature. The model predictions are successfully compared with published experimental data for different types of porous media. The new physically based model for electrical conductivity opens up new possibilities to characterize porous media under partially saturated conditions with geoelectrical and electromagnetic techniques.

scholarly journals A Novel Integrated Approach of Relevance Vector Machine Optimized by Imperialist Competitive Algorithm for Spatial Modeling of Shallow Landslides

2018 ◽  
Vol 10 (10) ◽  
pp. 1538 ◽  
Author(s):  
Dieu Tien Bui ◽  
Himan Shahabi ◽  
Ataollah Shirzadi ◽  
Kamran Chapi ◽  
Nhat-Duc Hoang ◽  
...  
Keyword(s):  
Landslide Susceptibility ◽  
Imperialist Competitive Algorithm ◽  
Relevance Vector Machine ◽  
Support Vector ◽  
Predictive Capability ◽  
Competitive Algorithm ◽  
Susceptibility Modeling ◽  
Gis Database ◽  
Proposed Model ◽  
Soft Computing Techniques

This research aims at proposing a new artificial intelligence approach (namely RVM-ICA) which is based on the Relevance Vector Machine (RVM) and the Imperialist Competitive Algorithm (ICA) optimization for landslide susceptibility modeling. A Geographic Information System (GIS) spatial database was generated from Lang Son city in Lang Son province (Vietnam). This GIS database includes a landslide inventory map and fourteen landslide conditioning factors. The suitability of these factors for landslide susceptibility modeling in the study area was verified by the Information Gain Ratio (IGR) technique. A landslide susceptibility prediction model based on RVM-ICA and the GIS database was established by training and prediction phases. The predictive capability of the new approach was evaluated by calculations of sensitivity, specificity, accuracy, and the area under the Receiver Operating Characteristic curve (AUC). In addition, to assess the applicability of the proposed model, two state-of-the-art soft computing techniques including the support vector machine (SVM) and logistic regression (LR) were used as benchmark methods. The results of this study show that RVM-ICA with AUC = 0.92 achieved a high goodness-of-fit based on both the training and testing datasets. The predictive capability of RVM-ICA outperformed those of SVM with AUC = 0.91 and LR with AUC = 0.87. The experimental results confirm that the newly proposed model is a very promising alternative to assist planners and decision makers in the task of managing landslide prone areas.

Time-temperature and time-stress correspondence in nonlinear creep. Experimental behaviour of amorphous polymers and quantitative modelling approaches

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
José R. S. André ◽  
José J. C. Cruz Pinto
Keyword(s):  
Nonlinear Creep ◽  
Predictive Capability ◽  
Kinetic Formulation ◽  
Time Stress ◽  
Relative Contribution ◽  
Proposed Model ◽  
Fully Coupled ◽  
Experimental Behaviour ◽  
Modelling Approach

Abstract Non-linear creep is described by a non-simulative, analytical, dynamic molecular modelling approach. Elementary, molecular-scale, process-relevant frequencies are derived by adequate kinetic formulation. They follow almost exactly an Arrhenius-like behaviour with a range of activation enthalpies. Their relative contribution to the overall macroscopic behaviour of the materials is quantified to account for the materials’ retardation time spectra and final non-Arrhenius behaviour. A new creep compliance equation is derived, yielding a fully coupled timetemperature- stress formulation, with long-term predictive capability. Experimental data for poly(methyl methacrylate) are analysed to identify the extent to which timetemperature and time-stress correspondence relationships may be valid, and it is shown that they are approximations (especially the latter), limited to narrow ranges of experimental variables, in contrast to the proposed model, which more reasonably fits the experimental behaviour.

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