Green Materials Comparison of Sawdust and Coconut Fiber Acoustical Waffle Panel

2015 ◽  
Vol 747 ◽  
pp. 221-225 ◽  
Author(s):  
Erni Setyowati ◽  
G. Hardiman ◽  
Sugeng Tirta Atmaja
Keyword(s):  
Absorption Coefficient ◽  
Natural Resources ◽  
Research Method ◽  
Building Materials ◽  
Transmission Loss ◽  
Coconut Fiber ◽  
A Value ◽  
Green Materials ◽  
Absorber Material ◽  
Wide Range

The natural wealth of Indonesia produces a wide range of natural resources. This research will discuss sawdust and coconut fiber for example from natural resources which can be processed into building materials. Various researches have studied the absorber made from sawdust and coconut fiber, but only a few studies that made the absorber material that had the texture of waffle on its surface. The research method used was the method comparisons of density, absorption coefficient and Sound Transmission Loss (STL). The result is that the waffle panel from sawdust has a higher density than the waffle panel made of coconut fiber. The STL of the coconut fiber panel has ranged between 46,134 – 51,312 dB. This value is lower than the STL material of sawdust that has a value between 47,301 – 62,688 STL. The absorption coefficient of coconut fiber panels is 0,432–0,511, while the absorption coefficient of sawdust panel has range of 0,469 – 0,529.

Sound Absorption Characteristics of a Single Micro-Perforated Panel Backed by a Natural Fiber Absorber Material

2020 ◽  
Vol 307 ◽  
pp. 291-296 ◽  
Author(s):  
Meifal Rusli ◽  
Fakhrur Rahman ◽  
Hendery Dahlan ◽  
Gusriwandi ◽  
Mulyadi Bur
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Natural Fibers ◽  
Absorption Characteristic ◽  
Coconut Fiber ◽  
Single Leaf ◽  
Absorber Material ◽  
Resonance Absorber ◽  
Absorption Characteristics

A micro-perforated panel (MPP) works as a Helmholtz-type resonance absorber formed by an air-gab cavity in order to minimize the reflected sound effectively at a selective resonance frequency. Furthermore, the use of natural fibers as sound absorbing materials recently has attracted more attention because it is completely biodegradable, environmental friendly and more economical. In this paper, the combination of MPP and natural fiber as sound absorptive material is investigated. The MPP is made of a transparent acrylic board with 1.5 mm thickness and backed by a coconut fiber panel. The effect of the fiber panel that inserted in the air-gab cavity to the sound absorption characteristic of a single leaf MPP is observed. Sound absorption coefficient is measured by transfer function method using two microphones-impedance tube. It is found that the sandwich model of MPP backed by a coconut fiber changes the sound absorption characteristics of MPP by shifting the maximum absorption coefficient into the lower frequency and making a wider band of frequency absorption. Moreover, the air-gab cavity between MPP and fiber panel give fewer contribution to construct the MPP frequency resonant than the natural fiber panel one.

scholarly journals Characteristics of Coconut Coir Composite Acoustic with Epoxy Matrix

2017 ◽  
Vol 1 (2) ◽  
pp. 46
Author(s):  
Lia Solikhatul Amalia ◽  
Andi Fadllan ◽  
Abdul Wahib
Keyword(s):  
Composite Material ◽  
Absorption Coefficient ◽  
Natural Resources ◽  
Epoxy Matrix ◽  
Crude Fiber ◽  
Font Size ◽  
Coconut Fiber ◽  
Fine Fiber ◽  
Coconut Coir

<p style="text-align: justify;"><span style="font-size: 10.0pt; line-height: 115%; font-family: 'Cambria','serif';">The aim of this research is to measure the absorption coefficient of composite material synthesized from coconut fiber as filler and epoxy matrix and to discover the alternative interval of sound reducer material from natural resources, i.e (coconut fiber : fine fiber, rough fiber and crude fiber). After pressing, the sample was then cutted and examined using Bruel and Kjaer characterization. From the characterization process, the absorption coefficient of composite with filler of fine, rough and crude coconut fiber is calculated and found to be 0.997, 0.97 and 0.96, respectively. </span><span style="font-size: 10.0pt; line-height: 115%; font-family: 'Cambria','serif'; color: black;">© 2015 JNSMR UIN Walisongo. All rights reserved.</span></p>

scholarly journals Vibration Damping and Acoustic Behavior of PU-Filled Non-Stochastic Aluminum Cellular Solids

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 725
Author(s):  
Vitor Hugo Carneiro ◽  
Hélder Puga ◽  
José Meireles
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Transmission Loss ◽  
Polyurethane Foams ◽  
Vibration Damping ◽  
Acoustic Properties ◽  
Sound Absorption Coefficient ◽  
Cellular Solids ◽  
Infiltration Process ◽  
Wide Range

Aluminum-based cellular solids are promising lightweight structural materials considering their high specific strength and vibration damping, being potential candidates for future railway vehicles with enhanced riding comfort and low fuel consumption. The filling of these lattices with polymer-based (i.e., polyurethane) foams may further improve the overall vibration/noise-damping without significantly increasing their density. This study explores the dynamic (i.e., frequency response) and acoustic properties of unfilled and polyurethane-filled aluminum cellular solids to characterize their behavior and explore their benefits in terms of vibration and noise-damping. It is shown that polyurethane filling can increase the vibration damping and transmission loss, especially if the infiltration process uses flexible foams. Considering sound reflection, however, it is shown that polyurethane filled samples (0.27–0.30 at 300 Hz) tend to display lower values of sound absorption coefficient relatively to unfilled samples (0.75 at 600 Hz), is this attributed to a reduction in overall porosity, tortuosity and flow resistivity. Foam-filled samples (43–44 dB at 700–1200 Hz) were shown to be more suitable to reduce sound transmission rather than reflection than unfilled samples (21 dB at 700 Hz). It was shown that the morphology of these cellular solids might be optimized depending on the desired application: (i) unfilled aluminum cellular solids are appropriate to mitigate internal noises due to their high sound absorption coefficient; and (ii) PU filled cellular solids are appropriate to prevent exterior noises and vibration damping due to their high transmission loss in a wide range of frequencies and vibration damping.

MANUFACTURE OF ACOUSTICAL ONE SIDE-WAFFLE PANEL MADE OF NATURAL RESOURCES WITH HYDRAULIC HOT PRESS MACHINE

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
E. Setyowati ◽  
A. Satyapratama ◽  
S. T. Atmadja ◽  
G. Hardiman
Keyword(s):  
Tensile Stress ◽  
Natural Resources ◽  
Transmission Loss ◽  
Structural Strength ◽  
Machine Design ◽  
Hot Press ◽  
Coconut Fiber ◽  
Wood Sawdust ◽  
Transverse Tensile ◽  
Steel Material

Waste generated from natural resources should be recycled as more useful materials. This research has produced acoustical waffle panel material which is useful as an absorber on the noisy housing. Acoustical waffle panels was made by Hydraulic Hot Press machine. The purpose of this discussion is to describe the machine design process and compare waffle panels made of coconut fiber and wood sawdust in the best acoustic performances. The result is that the hydraulic hot press machine has the structural strength and stability on the load of 2,500 N and 5,000 N. The hot press machine is safe for both the transverse tensile stress and longitudinal tensile stress which are smaller than the allowable stress of steel material of 40 at 1,100 kg/cm2. It also has the highest Sound Transmission Loss (STL) with the value of 40. 059 dB.

scholarly journals Acoustic Performance Evaluation of Sugarcane Bagasse Using Ambient Sound Meter and Scanning Electron Microscopy

2021 ◽  
Vol 9 (9) ◽  
pp. 1985-1996
Author(s):  
Aarushi Nigam
Keyword(s):  
Sugarcane Bagasse ◽  
Building Materials ◽  
Natural Fiber ◽  
Transmission Loss ◽  
Alkali Treatment ◽  
Low Cost ◽  
Agricultural Waste ◽  
Synthetic Materials ◽  
Green Materials ◽  
Sound Barriers

Abstract: Non-stop research is afoot to replace synthetic materials with green-materials for sound absorption purposes. Employing of agricultural waste as building materials has been a successful trend throughout the years. This research targets to utilize sugarcane bagasse (SB) fibers as sound barriers with sodium silicate as an adhesive. The SB fibers were treated in an alkaline solution for delignification and to improve the surface morphology. The SB fibers were casted into sheet and further tested for sound transmission loss. Experimentation revealed that the fabricated sheets can be viable option as a sound absorbing medium. A tubular porous structure was observed through Field Emission Scanning Microscope (FESEM). It has the capability to be used as a low-cost, biodegradable, and eco-friendly acoustic material as compared to glass wool and other synthetic acoustic materials. Keywords: Acoustic material, Alkali-treatment, Ambience, FESEM microscopy, Low-cost, Natural fiber, Performance, Sugarcane Bagasse, Sustainability

Estimating Pigment Concentrations from Spectral Images Using an Encoder‐Decoder Neural Network

2020 ◽  
Vol 64 (3) ◽  
pp. 30502-1-30502-15
Author(s):  
Kensuke Fukumoto ◽  
Norimichi Tsumura ◽  
Roy Berns
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Absorption Coefficient ◽  
Spectral Data ◽  
High Accuracy ◽  
Pigment Concentration ◽  
Scattering Coefficient ◽  
A Value ◽  
Input And Output ◽  
Pigment Concentrations

Abstract A method is proposed to estimate the concentration of pigments mixed in a painting, using the encoder‐decoder model of neural networks. The model is trained to output a value that is the same as its input, and its middle output extracts a certain feature as compressed information about the input. In this instance, the input and output are spectral data of a painting. The model is trained with pigment concentration as the middle output. A dataset containing the scattering coefficient and absorption coefficient of each of 19 pigments was used. The Kubelka‐Munk theory was applied to the coefficients to obtain many patterns of synthetic spectral data, which were used for training. The proposed method was tested using spectral images of 33 paintings, which showed that the method estimates, with high accuracy, the concentrations that have a similar spectrum of the target pigments.

Perempuan dan Liminalitas dalam Tradisi Perkawinan Adat di Timor Tengah Selatan

2020 ◽  
Vol 6 (1) ◽  
pp. 114
Author(s):  
Marsel Eliaser Liunokas
Keyword(s):  
Qualitative Research ◽  
Research Method ◽  
Literature Study ◽  
Qualitative Research Method ◽  
South Central ◽  
A Value ◽  
Traditional Marriage ◽  
The Village ◽  
As If

Timorese culture is patriarchal in that men are more dominant than women. As if women were not considered in traditional rituals so that an understanding was built that valued women lower than men. However, in contrast to the article to be studied, this would like to see the priority of women’s roles in traditional marriages in Belle village, South Central Timor. The role of women wiil be seen from giving awards to their parents called puah mnasi manu mnasi. This paper aims to look at the meaning of the rituals of puah mnasi maun mnasi and the role and strengths that women have in traditional marriage rituals in the village of Belle, South Central Timor. The method used for this research is a qualitative research method using interview techniques with a number of people in the Belle Villa community and literature study to strengthen this writing. Based on the data obtained this paper shows that the adat rituals of puah mnasi manu mnasi provide a value that can be learned, namely respect for women, togetherness between the two families, and brotherhood that is intertwined due to customary marital affrairs.

Recycling and Reuse in the Roman Economy

2020 ◽  
Keyword(s):  
Building Materials ◽  
Computational Modelling ◽  
Late Antique ◽  
Roman Economy ◽  
Wide Range ◽  
The Status ◽  
Recent Developments ◽  
Methodological Approaches ◽  
First Time ◽  
Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

Path Integral Calculations of Particle Self-Energy and Effective Mass in Coulomb Systems

1997 ◽  
Vol 11 (04) ◽  
pp. 129-138 ◽  
Author(s):  
V. Sa-Yakanit ◽  
V. D. Lakhno ◽  
Klaus Haß
Keyword(s):  
Effective Mass ◽  
Path Integral ◽  
State Energy ◽  
Coulomb Systems ◽  
Integral Approach ◽  
Coupling Region ◽  
Self Energy ◽  
Consistent Approximation ◽  
A Value ◽  
Wide Range

The generalized path integral approach is applied to calculate the ground state energy and the effective mass of an electron-plasmon interacting system for a wide range of densities. It is shown that in the self-consistent approximation an abrupt transition between the weak coupling and the strong coupling region of interaction exists. The transition occurs at low electron densities according to a value of 418 for rs, when Wigner crystallization is possible. For densities of real metals, the electron bandwidth is calculated and a comparison with experimental results is given.

scholarly journals Characterization of a Novel CaCO3-Forming Alkali-Tolerant Rhodococcus erythreus S26 as a Filling Agent for Repairing Concrete Cracks

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2967
Author(s):  
Seunghoon Choi ◽  
Sungjin Park ◽  
Minjoo Park ◽  
Yerin Kim ◽  
Kwang Min Lee ◽  
...  
Keyword(s):  
Building Materials ◽  
Culture Fluid ◽  
Natural Phenomenon ◽  
Environment Friendly ◽  
Wide Range ◽  
Filling Agent ◽  
Calcium Source ◽  
Alkali Tolerance ◽  
High Alkali

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4–10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20–60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4–0.6 mm width.

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