Sound Material Research Articles

Analysis of noise reduction in natural gas pressure-boosted power generation equipment

Abstract To address the issue of excessive noise from the natural gas pressure-boosted power generation equipment, this paper conducts a noise analysis on the equipment at a natural gas purification plant in the Southwest oil and gas field. It identifies the primary sources and mechanisms contributing to the noise from the pressure-boosted power generation equipment. The paper clarifies the effectiveness of the existing noise control measures. It proceeds to conduct indoor experimental research on the noise reduction effects of different combinations of sound insulation and absorption materials. It selects optimal noise reduction strategies suitable for different frequency spectra of noise sources and proposes recommendations for noise reduction measures. Additionally, it employs CadnaA software to simulate and validate the noise reduction effects.

Study on the properties of anorthite-based porous sound-absorbing materials prepared by steel slag and fly ash

The efficient utilization of solid wastes, such as fly ash and steel slag, has attracted significant attention across the globe. In this paper, these two kinds of waste materials are used to prepare porous sound-absorbing materials, so as to achieve efficient resource utilization and environmental protection, and promote green manufacturing and circular economy. In this study, steel slag and high-alumina fly ash were used as the primary raw materials to prepare green bodies via organic foam impregnation. Subsequently, a high-temperature sintering process was implemented to get the porous sound absorption material product from the green bodies. The effects of several factors, including the ratio of steel slag and fly ash, sintering temperature, and pore structure, on the sound absorption and mechanical properties of the product were investigated. Based on the anorthite region in the CaO–Al2O3–SiO2 ternary phase diagram region, the composition ratio of the material was designed. The composition and microstructure of the material were characterized by X-ray diffraction and scanning electron microscopy. From the results, with the increase of the ratio of fly ash and steel slag, the composition of low melting point substances in the system decreases, and the amount of liquid phase decreases, which weakens the pore blocking phenomenon inside the material, resulting in the increase of pore size and noise reduction coefficient of the material. Besides, higher sintering temperature tends to correlate to greater density and higher compressive and flexural strengths but lower porosity, and the sound absorption coefficient demonstrated a peak with respect to sintering temperature. Furthermore, when the reduction of polyurethane sponge body pore size was taken into account, the product's sound absorption coefficient also showed a peak. The optimal parameters for our porous materials are as follows: fly ash:steel slag = 48 : 25, polyurethane sponge pore size = 40 ppi, sintering temperature = 1160 °C at 1-h duration (bulk density = 573.98 kg/m3), compressive strength = 1 MPa, porosity = 79.35 %, and noise reduction coefficient = 0.47.

Feasibility Test of Guided Inquiry Model Learning Devices Assisted by 3D Experimental Media on Sound Wave Material

This research aims to determine the feasibility of a guided inquiry model physics learning device assisted by 3D experimental media on sound wave material. The type of research used is research and development with a 4D research model. The products developed are syllabi, learning implementation plans (RPP), student worksheets (LKPD), and test instruments. Data collection was carried out through validation sheets of learning tools by expert validators and practitioners, and reliability analysis using percentage of agreement (PA). The validation results obtained show that the syllabus, RPP, LKPD and test instruments with an overall average of 86.29% are in very valid criteria and the results of the reliability analysis show that the overall average value of the learning tools is 93.32% in reliable criteria. Based on this, it can be concluded that the guided inquiry learning tool assisted by 3D experimental media is suitable for application in learning sound waves in the classroom.

VALIDITY OF GUIDED INQUIRY-BASED PHYSICS LEARNING MODULE

The learning resources used in learning physics class XI SMAN 1 Namorambe is only a package book. In fact, teachers and students are not satisfied with the existing learning resources, therefore a new learning resource is needed and is expected to meet the needs of teachers and students. This research focuses on the development of physics learning modules on sound waves material class XI SMA. This study aims to determine the validity level of the guided inquiry-based module on the subject of sound waves that have been developed. This research is an R & D (Research and Development) development research using the 4-D model which has four main stages, namely the defining stage (define), the design stage (Design), the development stage (Development), and the dissemination stage (disseminate). The research instruments used are validation instruments consisting of validation instruments by material experts and media expert validation instruments. The results showed that the validity level of the guided inquiry-based physics learning module produced was on very valid criteria so it was feasible to use in learning.

Inovasi Pembelajaran Fisika: Integrasi Problem Based Learning dan Simulasi PhET pada Materi Gelombang Bunyi

This research is motivated by the low learning outcomes of physics students, especially on sound waves material. The purpose of this research is to evaluate the effectiveness of Problem Based Learning (PBL) learning model assisted by PhET simulation in improving students' physics learning outcomes. The research method used was a pseudo experiment with a sample of 28 students of class XI IPA 2 at SMA Negeri 2 Kupang. The data obtained were analyzed by quantitative descriptive method. The results showed that after the application of PBL learning model with PhET simulation there was a significant increase in student learning outcomes. From the results of cognitive tests before treatment (pre-test), there were no students who reached the average percentage level of scores ≥ 75%, with an average score of 19. After the treatment (post-test), 25 out of 28 students were declared complete with an average percentage level of 95 or ≥ 75%. At the stage of observation and observation of affective abilities, 25 students reached an average percentage level ≥ 75%, and 3 students were still below 75%. In the follow-up observation on the psychomotor spec, 26 students reached an average percentage level ≥ 75%, and 2 students were still below 75%. The application of PBL model assisted by PhET simulation is effective in improving students' physics learning outcomes on sound wave material.

Underwater sound absorption characteristics of water-saturated porous materials

In this research, the underwater sound absorption performance of porous media saturated with water is investigated through long straight tubes (LSTs) with circular cross-section and sintered fibrous metals (SFMs) containing complex pores, and effective underwater sound absorption capability is demonstrated theoretically, numerically and experimentally. Specifically, the theoretical model for LSTs, verified by direct numerical simulations (DNSs), reveals that much smaller pore diameter and much larger layer thickness of porous material is needed to gain high waterborne sound absorption coefficient than to obtain large airborne sound absorption coefficient. Besides, to examine the sound absorption capacity of realistic porous materials, SFMs backed with a finite cavity are experimentally measured under 7 different hydrostatic pressures in a water-filled tube, and numerically characterized via multi-physics couplings. Insensitivity of effective sound absorption capability to high pressure is established, which stems from the different underwater wave energy consumption mechanism (i.e. viscous-thermal effect) of porous materials from conventional rubber kind of underwater sound absorption materials. Physically, porous materials possess great potential in developing the next generation of high-performance underwater sound absorption materials.

Advanced acoustic design: 3D printed thermoplastic folded core sandwich structures with porous materials and microperforations for enhanced sound absorption

This study introduces a novel sound-absorbing sandwich structure with a folded core, created through 3D printing technology, to address the challenge of weak sound absorption in the low-frequency range in sound absorption materials (SAMs). The structure comprises chopped carbon fiber–dispersed thermoplastic polyamide (CF-PA), continuous carbon fiber (CCF) filaments, and polyurethane (PU) foam coated with graphene oxide (GO). Simulation studies revealed that optimized structural parameters and microperforation diameters resulted in enhanced sound absorption coefficient (SAC) of 99 % or more at 1250 Hz, within the low-frequency range (160–1600 Hz). The GO-coated PU foam SAMs demonstrated excellent sound absorption performance measured in the high-frequency range (1600–6000 Hz), achieving 99 % SAC at 2400 Hz. Furthermore, the manufactured folded core structure exhibited outstanding sound absorption performance, achieving SAC of 99 % at 732 Hz measured in the low-frequency (160–1600 Hz) band and 99 % at 600 Hz, showcasing broad absorption capabilities measured in the high-frequency band (160–6000 Hz). Additionally, a flatwise compression test on the structure filled with GO-coated PU foam demonstrated a 32 % improvement in compressive load, indicating the structure’s versatility for various applications.

Development of E-Module Learning Media based on SETS (Science, Environment, Technology, and Society) on Sound Wave Material

Electronic Module (E-Module) is a type of interactive multimedia teaching material presented electronically which contains images, text and videos arranged systematically which are useful for forming a more creative learning process. The learning process at State Islamic Senior High School of 3 North Aceh currently still uses the conventional model and teachers have never conducted learning using interactive learning media such as e-modules. This research aims to determine the feasibility and practicality of SETS-based e-module learning media products as media that make it easier for students to learn sound wave material for class XI at the State Islamic Senior High School of 3 North Aceh. This development research method refers to Research and Development (R&D) with the ADDIE model (Analysis, Design, Development, Implementation and Evaluation). The research subjects were physics subject teachers at the State Islamic Senior High School of 3 North Aceh and students in class XI MIA 3 with a total of 16 students. The results obtained are: 1) The results of validation by the media obtained a percentage of 85.23% in the "Very Eligible" category, and the validation results from material experts obtained a percentage of 85.06% in the "Very Eligible" category. 2) The results of student responses (small scale) obtained a percentage of 89.08% in the "very practical" category. 3) The results of teacher responses obtained a percentage of 82.96% in the "Very Practical" category and the results of student responses (large scale) obtained a percentage of 86. 97% in the "Very Practical" category.

THE PIANO PHENOMENON IN KARMELLA TSEPKOLENKO’S CREATIVITY: FROM CONTENT TO RECORD

The study is focused on the main works of the piano creativity by Carmella Tsepkolenko. This concerns her Concerto-drama No. 1 and Concerto-drama No. 2 for piano and orchestra, which are seen as one megastructure that is open to further continuation. The compositional techniques used in them are described. It has been found that the presentation of musical material by means of modern notation gives the performer the opportunity to more clearly define his own attitude to the work and opens wide prospects for a unique interpretation. The role of the piano in Carmella Tsepkolenko's work is emphasized as a leading tool for searching for new means of self-expression and communication with the listener. It has been established that the rejection in avant-garde music of traditionally established principles of notation and changes in the organization of sound material, as well as its presentation on paper, took place under the influence of deep crisis phenomena of the 20th century and changes in society's consciousness. Emphasis is placed on the inevitability of establishing empathic connections between the author and the performer, taking into account the specifics of the presentation of the musical material. It was established that Carmella Tsepkolenko's individual compositional style is characterized by the use of not only traditional means of notation, but also the wide use of such types of modern compositional techniques as atonality, aleatorics, pointillism, sonoristics. The main feature of the composer's individual compositional style is characterized — the presence of obligatory scenario development of each work. The general orientation of Carmella Tsepkolenko's work towards theatricality in music of all genres is emphasized. It is proven that in order to create a convincing artistic image, the author sometimes turns to the artistic medium so-called Performance, which requires certain acting skills from the performer. The expediency of using a performing gesture as a special artistic tool that enhances the emotional impact on the listener is substantiated. Emphasis is placed on the need for performers to familiarize themselves with the basics of modern musical notation in educational institutions.

PENERAPAN MODEL PEMBELAJARAN GUIDED INQUIRY BERBANTUAN PRAKTIKUM TERHADAP KETERAMPILAN PROSES SAINS SISWA PADA MATERI GELOMBANG BUNYI

This research aims to determine the effect of students' science process skills using the guided inquiry learning model assisted by practicum on sound wave material at SMA Negeri 6 Serang City. The research method used is quasi-experimental with a one group pretest-posttest design approach. The research results show that the average N-gain value is 0.11 in the low category for the pretest and the posttest N-gain is 0.49 in the medium category. The average percentage result on the students' science process skills observation sheet is 78.40% in the good category. Based on the research results, there is an influence of the application of the guided inquiry learning model assisted by practicum on students' science process skills in the material of sound waves.

Lime Hempcrete Composites Based on Unfired Binders. A Review

AbstractHempcrete has emerged as a viable and environmentally sound building material based on hemp lime mixture, whose properties render it a low Embodied Energy and Carbon (EE and EC) building material. Additionally, it allows a hempcrete building to achieve low Operational Energy and Carbon (OE and OC) by moderating indoor temperature and relative humidity fluctuations through the year with minimal auxiliary heating or cooling. Hemp shives used in hempcrete are a waste product, yet lime is an energy intensive material. This paper summarizes a research project the purpose of which was to investigate the possibility of substituting the lime in hempcrete with unfired binders, in part of whole, thus lowering the EE and EC of the mixture even further. Results of this research have shown that this is possible without compromising any of the traditional hempcrete properties, e.g., compressive strength and insulating value. A comprehensive Life Cycle Energy Analysis (LCEA) and Life Cycle Carbon Analysis (LCCA) has shown total energy requirements for a prototypical building’s lifespan (50 years) to be between ~ 50–10% of an identical building with conventional materials, and total carbon emissions to be respectively ~ 50–10%.

Advancing Sustainable Acoustic Solution: Exploring the Sound Absorption Characteristics of Biodegradable Agricultural Wastes, Coconut Fiber, Groundnut Shell, and Sugarcane Fiber

Among the world's greatest threats is noise pollution particularly in megacities that affect the quality of life. This problem can cause negative effects on human health, disturbing emotion as well as human behavior. Natural fiber sound insulation materials have been demonstrated to be a potential substitute for the synthetic products currently employed in the sound insulation industry. Coconut fiber and sugarcane fiber happen to be biodegradable, earth-friendly, and present lower risks to the environment and human health. The research examines the sound absorption characteristics of natural biodegradable waste fibers (coconut fiber & sugarcane fiber) to evaluate their suitability as sound absorbers. The paper seeks to discover the internal workings of the sound absorption mechanisms of these materials and also to help design environmentally friendly acoustic solutions.

Introduction to Magic E in Reading English Words CVCe

English vowels consist of five letters that have different pronunciations (sounds) in English words. There are 20 vowel sounds and 24 consonant sounds in English. It is a challenge for English teachers to teach English learners the concept of reading English words. English vowels with the symbols a, i, u, e, and o have different pronunciations when they are positioned between consonants in the word CVC and when the word CVC is added by the letter e in the word CVCe. Therefore, this paper analyzed the influence of the letter e (which is referred to as magic e) in the pronunciation of English vowel sounds. This research is qualitative research with documentation study methods to analyze and explain how the vowel sounds are pronounced in CVC and CVCe words so that English reading teaching steps are obtained that are easy to understand. The results showed that English vowels were pronounced as short vowel sounds in CVC words and pronounced as long vowel sounds in CVCe words. The steps to teach magic e that can be applied are to repeat the short vowel sound material, introduce the concept of sounds and letters, introduce the concept of short and long vowel sounds, read two words similar in the concept of CVC and CVCe, and practice reading the word CVCe regularly.

Mechanically robust poly(urethane-imide) aerogels with excellent thermal insulation and sound absorption by ambient drying

Polyimide (PI) aerogels are the great candidates for sound absorption, thermal insulation and mechanical cushioning materials due to their low density, excellent mechanical properties and good thermal stability. However, the high shrinkage and hydrophilicity of PI aerogels, as well as the time-consuming and complexity of the process directly limit their wide application in many fields. Herein, a facile one-step method for the synthesis of porous monolithic poly(urethane-imide) (PUI) aerogels was successfully developed. Hydrothermal synthesis and ambient drying methods were adopted in the construction of monolithic chemically cross-linked PUI aerogels, which avoids the complex imidization process. PUI aerogels were homogeneously produced by a chemical cross-linking copolymerization reaction between polyurethane (PU) oligomers, Benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA) and 1, 3, 5-tris (6-isocyanatohexyl)-1, 3, 5-triazine-2, 4, 6(1H, 3H, 5H)-trione without any catalysts. Interestingly, the introduction of linear flexible PU oligomers chain segments effectively prevented the shrinkage of the network backbone and enhanced the hydrophobicity of PUI aerogels. The obtained PUI aerogels have low density (0.196 g/cm3), low shrinkage (9.30%), high porosity (79.54%) and hydrophobicity (water contact angle of 129.2°). Under high pressure, PUI aerogel was compressed but not break and the compression Young's modulus as high as 3.638 MPa. Moreover, the thermal conductivity of PUI aerogels was only 59.92 mW/m/K at 150 °C. When the back cavity depth was 5 mm, the highest sound absorption coefficient of PUI aerogel was up to 0.7219. This work provides a new method for the development of lightweight, high-mechanical-strength polymer aerogels, and the prepared aerogels have a potential application in the field of multifunctional integrated sound absorption materials.

Hot Corrosion Damage Modeling in Aeroengines Based on Performance and Flight Mission

Hot corrosion is a form of chemical damage that causes surface degradation, sound material loss, and reduced component life. A lifing analysis in aeroengines without considering hot corrosion can lead to unexpected damage findings and increased scrap rates due to blade thickness loss beyond repair. This paper presents a novel methodology to predict hot corrosion damage based on aeroengine performance and flight mission analysis while taking into account environmental exposure, fuel quality, and material factors. The participating mechanisms, from salt and sulfur ingestion to deposition and hot corrosion attack, are discussed to explain the phenomenon in aeroengine components. In the investigated engine type, the first stage of the low-pressure turbine is the most affected. The application of the new methodology provides insights into the damage progression during the flight, the most affected components and the importance of capturing variations in the fuel quality, environmental exposure at the flight region, and the thrust derate policy. For a representative 1500 n mile mission, the variations in environmental exposure, fuel quality, and derate policy within typical limits can result in up to +350% damage. The outputs of the new framework can inform the decision making for maintenance, repair, and overhaul contract costing and scheduling.

Development of Interactive Edugame Learning Media Based on Snakes & Ladders to Improve IPAS Learning Outcomes

The use of learning media that is a game has never been developed by teachers, resulting in low learning outcomes of IPAS light and sound material. The purpose of this study was to develop, test the feasibility, and effectiveness of interactive edugame learning media based on snakes & ladders to improve the cognitive learning outcomes of IPAS for fifth grade students of SD Negeri Candi 01 Semarang City. The type of research used is Research and Development (R&D) research with the Borg and Gall development model. The subjects of this research were 24 fifth grade students of SD Negeri Candi 01 Semarang City. Data collection techniques used non-test techniques (observation, interviews, questionnaires, data and documentation) and test techniques (pretest and posttest). The data analysis technique begins with the normality test, then the T test and the N-Gain test to show the final results. The results of this study are as follows 1) Snakes & ladders-based interactive edugame learning media was developed using Canva and Genially applications in the form of a flipbook with components, namely cover, preface, table of contents, character introduction, concept map, learning outcomes, learning objectives, materials, games, LKPD, images, animations, experimental videos, and HOTS questions. 2) The results of the feasibility test from media experts obtained a score of 91% with a very feasible category and material experts obtained a score of 93% with a very feasible category. 3) The effectiveness of snakes & ladders-based interactive edugame learning media comes from the results of the pretest and posttest, based on the cognitive learning outcomes of students showing an increase in change, namely the normality test analysis shows that the data is normally distributed. The T test results obtained Sig. (2-tailled) 0.001 <0.05. The N-Gain test results were 0.84 with high criteria. The conclusion of the development of interactive edugame media based on snakes & ladders was successfully developed with very feasible and effective to improve the cognitive learning outcomes of IPAS fifth grade students of SD Negeri Candi 01 Semarang City.

Down-film as a new non-frame porous material for sound absorption

Down-polyethylene film material has been introduced for the first time as an excellent non-frame sound absorber, showing a distinctively outstanding performance. It contains down fiber adjacent to each other without firm connection in between, forming a structure of elastic fiber network. The unique structure has broadband response to sound wave, showing non-synchronous vibration in low and middle frequency and synchronous vibration in middle and high frequency. The broadband resonance in middle and high frequency allows the structure to achieve complete sound absorption in resonance frequency band. Moreover, down-polyethylene film material possesses forced vibration, corresponding sound absorption coefficient has been obtained based on vibration theory. The down-film sound absorption material has the characteristics of light weight, soft, environment-friendly, and has excellent broadband sound absorption performance.

Green sound-absorbing material prepared by using natural fiber for building acoustics

Natural fibers are recently seen as a replacement for synthetic fibers as core material to produce sound-absorbent materials. These are biodegradable and renewable, and using them as sound-absorbent material brings many environmental benefits as it is much greener compared to existing inorganic and synthetic fibers. Present exploration serves the purpose of investigation and comparison of the acoustic absorption characteristics of individual and mixed natural fibers; jute, coconut coir, and bamboo. Each fiber is reinforced with natural rubber in a certain weight ratio during the fabricating stage. The fibers are then compressed with the help of mould and ram piston in a hydraulic press. The compression is done in the form of cylindrical samples of 40 mm diameter. Each specimen is kept 36 mm thick, according to the given standards. The impedance tube technique is used to evaluate acoustical performances. Multilayered composites made of layers of coir, jute, and bamboo performed better in all the frequency ranges than composites made of individual fibers. Results establish that these fibers are promising and a viable option for light and environment-friendly sound absorption materials.

Nonwoven acoustic panels from Himalayan nettle (Girardinia diversifolia L.) fibre

Sound absorption panels are being used extensively to mitigate the problem of noise pollution in buildings. Conventional materials used for sound absorption include glass wool, rock wool, mineral wool, asbestos, melamine, and polyurethane foam. However, recent studies show these materials can cause respiratory and skin problems. This has led to the search for natural and ecofriendly alternatives for sound absorbing materials. Lignocellulosic materials are cheap, renewable, biodegradable, and abundantly available and thus provide a viable option for use as sound absorbing materials. In this study, fibres extracted from the bark of Himalayan Nettle (Girardinia diversifolia L.) were used to prepare nonwoven webs using needle punching technique. Punch density was varied to create webs with variable properties. The effect of punch density on acoustic properties was studied. A positive correlation was observed between sample thickness and the Noise Reduction Coefficient. Samples having punch density of 75needles/cm2 showed the highest Noise Reduction Coefficient, attributable to their greater porosity and lower compactness. The study demonstrates that the morphological traits of the Himalayan nettle fibre, that is, a rough surface, flat elliptical cross-section, and a hollow core, make it an excellent sound absorption material. The acoustic properties can be tuned by varying the properties of the nonwoven web.

Simultaneously enhanced the sound absorption coefficient and dimensional stability of Carboxymethyl cellulose/clay aerogel by impregnating polyurethane

Carboxymethyl cellulose (CMC) aerogel could be used in the manufacture of highly efficient sound-absorbing materials because of its low density and sustainability. However, owing to its low mechanical strength and brittleness, preparing porous sound absorption materials with excellent sound absorption performance has always been a challenging problem. Herein, carboxymethyl cellulose/organic exfoliation of montmorillonite/thermoplastic polyurethane (CMC/OMMT/TPU) composite aerogels were successfully obtained via a simple impregnation and freeze-drying process. The effect of TPU and OMMT on the sound absorption properties of cellulose aerogels was detailedly discussed. The results revealed that the CMC/OMMT/TPU composite aerogel had hierarchically porous structures, and the sound absorption performance was significantly improved. The average sound absorption coefficient of CMC/OMMT/TPU composite aerogel could reach as high as 0.807 (500–6500 Hz). The main reason for this improvement is caused by the multiple scattering of sound waves on the arranged porous surface, as well as the viscous damping of the air inside the structure between the TPU, CMC and OMMT. Furthermore, the dimensional stability of the prepared aerogel is also greatly enhanced after using TPU. This work provides a new approach for the development of aerogel with stable morphology and sound absorption performance, which would be widely used in construction and military fields.