Search results for: sound absorption coefficients

Authors: Malinda Sabrina, Khoerul Anwar

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Railway noise generated by pass-by train has been described as a form of environmental pollutants especially for the residential area near the railway. Many studies have shown, that environmental noise particularly transportation noise has negative effects on people which resulting in annoyance and specific health problems such as cardiovascular disease, cognitive impairment and sleep disturbance. Therefore, various attempts are made to reduce the noise. One method of reducing such noise to acceptable noise levels is to build acoustically barrier walls. The objective of this study was to review the method of reducing railway noise and obtain the preliminary design of the acoustics barrier on the edge of railway tracks close to the residential area. The design of this barrier is using the Maekawa's method. Measurements have been performed in residential areas around the railroads in the Karawang - Indonesia with the absence of an acoustical barrier. From the observation, it was found that the railway was passed by five trains within thirty minutes. With the limited distance between the railway tracks and the location of the residential area as well as the street of residents, then it was obtained that a reduction in sound pressure level is 25 dBA. Maximum sound pressure level obtained is 86.9 dBA then by setting the barrier as high as 4 m at a distance, 2.5 m from the railway, the noise level received by residents in the settlement around the railway line becomes 61.9 dBA.

Keywords: acoustics barrier, Maekawa's method, noise attenuation, railway noise

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Authors: Faezeh Mosallat, Eric L. Bibeau, Tarek El Mekkawy

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Availability of a wide variety of renewable resources, such as large reserves of hydro, biomass, solar and wind in Canada provides significant potential to improve the sustainability of energy uses. As buildings represent a considerable portion of energy use in Canada, application of distributed solar energy systems for heating and cooling may increase the amount of renewable energy use. Parabolic solar trough systems have seen limited deployments in cold northern climates as they are more suitable for electricity production in southern latitudes. Heat production by concentrating solar rays using parabolic troughs can overcome the poor efficiencies of flat panels and evacuated tubes in cold climates. A numerical dynamic model is developed to simulate an installed parabolic solar trough facility in Winnipeg. The results of the numerical model are validated using the experimental data obtained from this system. The model is developed in Simulink and will be utilized to simulate a tri-generation system for heating, cooling and electricity generation in remote northern communities. The main objective of this simulation is to obtain operational data of solar troughs in cold climates as this is lacking in the literature. In this paper, the validated Simulink model is applied to simulate a solar assisted absorption cooling system along with electricity generation using organic Rankine cycle (ORC) and thermal storage. A control strategy is employed to distribute the heated oil from solar collectors among the above three systems considering the temperature requirements. This modeling provides dynamic performance results using real time minutely meteorological data which are collected at the same location the solar system is installed. This is a big step ahead of the current models by accurately calculating the available solar energy at each time step considering the solar radiation fluctuations due to passing clouds. The solar absorption cooling is modeled to use the generated heat from the solar trough system and provide cooling in summer for a greenhouse which is located next to the solar field. A natural gas water heater provides the required excess heat for the absorption cooling at low or no solar radiation periods. The results of the simulation are presented for a summer month in Winnipeg which includes the amount of generated electric power from ORC and contribution of solar energy in the cooling load provision

Keywords: absorption cooling, parabolic solar trough, remote community, validated model

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Authors: Dalhat Binta Dan - Ali

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The reality of the new world economic order and the ever increasing importance of biotechnology in the global economy have necessitated the ratification of the Cartagena Protocol on Biosafety and the recent promulgation of Biosafety Act in Nigeria 2015. The legal regimes are anchored on the need to create an enabling environment for the flourishing of bio-trade and also to ensure the safety of the environment and human health. This paper critically examines the legal framework on biosafety by taking a cursory look at its philosophical foundation, key issues and milestones. The paper argues that the extant laws, though a giant leap in the establishment of a legal framework on biosafety, it posits that the legal framework raises debate and controversy on the difficulties of risk assessment on biodiversity and human health, other challenges includes lack of sound institutional capacity and the regimes direction of a hybrid approach between environmental conservation and trade issues. The paper recommend the need for the country to do more in the area of stimulating awareness and establishment of a sound institutional capacity to enable the law ensure adequate level of protection in the field of safe transfer, handling, and use of genetically modified organisms (GMOs) in Nigeria.

Keywords: Cartagena protocol, biosafety, issues, challenges, biotrade, genetically modified organism (GMOs), environment

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Authors: Ravi Teja Mandapaka, Prasanna Kumar Kukkamalla

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Poor absorption of calcium, elevated levels in serum and loss of bone are major problems of astronauts during space travel. Supplementation of calcium could not reveal this problem. In normal condition only 33% of calcium is absorbed from dietary sources. In this paper effect of space environment on calcium metabolism was discussed. Many surprising study findings were found during literature survey. Clinical trials on ovariectomized mice showed that reduction of calcium particles to nano level make them more absorbable and bioavailable. Control of bone loss in astronauts in critical important In Fortification of milk with nana calcium particles showed reduces urinary pyridinoline, deoxypyridinoline levels. Dietary calcium and supplementation do not show much retention of calcium in zero gravity environment where absorption is limited. So, the fortification of foods with nano calcium particles seemed beneficial for astronauts during and after space travel in their speedy recovery.

Keywords: nano calcium, astronauts, fortification, supplementation

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Authors: Nguyen J. M., Lucas G., Brunner M., Ruan S., Antonioli D.

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Deep learning based on convolutional neural networks (CNN) is a very powerful technique for classifying information from an image. We propose a new method, DeepNic, to transform each variable of a tabular dataset into an image where each pixel represents a set of conditions that allow the variable to make an error-free prediction. The contrast of each pixel is proportional to its prediction performance and the color of each pixel corresponds to a sub-family of NICs. NICs are probabilities that depend on the number of inputs to each neuron and the range of coefficients of the inputs. Each variable can therefore be expressed as a function of a matrix of 2 vectors corresponding to an image whose pixels express predictive capabilities. Our objective is to transform each variable of tabular data into images into an image that can be analysed by CNNs, unlike other methods which use all the variables to construct an image. We analyse the NIC information of each variable and express it as a function of the number of neurons and the range of coefficients used. The predictive value and the category of the NIC are expressed by the contrast and the color of the pixel. We have developed a pipeline to implement this technology and have successfully applied it to genomic expressions on an Affymetrix chip.

Keywords: tabular data, deep learning, perfect trees, NICS

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Authors: Marina Karaseva

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The beginning of our century became a new digital epoch in the educational situation. Last decade the newest stage of this process had been initialized by the touch-screen mobile devices with program applications for them. The touch possibilities for learning fundamentals of music are of especially importance for music majors. The phenomenon of touching, firstly, makes it realistic to play on the screen as on music instrument, secondly, helps students to learn music theory while listening in its sound elements by music ear. Nowadays we can detect several levels of such mobile applications: from the basic ones devoting to the elementary music training such as intervals and chords recognition, to the more advanced applications which deal with music perception of non-major and minor modes, ethnic timbres, and complicated rhythms. The main purpose of the proposed paper is to disclose the main tendencies in this process and to demonstrate the most innovative features of music theory applications on the base of iOS and Android systems as the most common used. Methodological recommendations how to use these digital material musicologically will be done for the professional music education of different levels. These recommendations are based on more than ten year ‘iTheory’ teaching experience of the author. In this paper, we try to logically classify all types of ‘iTheory’mobile applications into several groups, according to their methodological goals. General concepts given below will be demonstrated in concrete examples. The most numerous group of programs is formed with simulators for studying notes with audio-visual links. There are link-pair types as follows: sound — musical notation which may be used as flashcards for studying words and letters, sound — key, sound — string (basically, guitar’s). The second large group of programs is programs-tests containing a game component. As a rule, their basis is made with exercises on ear identification and reconstruction by voice: sounds and intervals on their sounding — harmonical and melodical, music modes, rhythmic patterns, chords, selected instrumental timbres. Some programs are aimed at an establishment of acoustical communications between concepts of the musical theory and their musical embodiments. There are also programs focused on progress of operative musical memory (with repeating of sounding phrases and their transposing in a new pitch), as well as on perfect pitch training In addition a number of programs improvisation skills have been developed. An absolute pitch-system of solmisation is a common base for mobile programs. However, it is possible to find also the programs focused on the relative pitch system of solfegе. In App Store and Google Play Market online store there are also many free programs-simulators of musical instruments — piano, guitars, celesta, violin, organ. These programs may be effective for individual and group exercises in ear training or composition classes. Great variety and good sound quality of these programs give now a unique opportunity to musicians to master their music abilities in a shorter time. That is why such teaching material may be a way to effective study of music theory.

Keywords: ear training, innovation in music education, music theory, mobile devices

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Authors: Khadijat Ayanpeju Abdulsalam, Bolanle Mary Olawoye, Paul Babatunde Ayoola

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The potential of Baobab leaves is understudied and not yet fully documented. The purpose of this work is to highlight the important nutritional value and practical qualities of baobab leaves. In this research, proximate analysis was studied to determine the macronutrient quantitative analysis in baobab leaves. Studies were also conducted on other characteristics, such as moisture content, which is significant to the food business since it affects food quality, preservation, and resistance to deterioration. Dietary fiber, which was also studied, has important health benefits, such as lowering blood cholesterol levels by lowering low-density lipoprotein or "bad" cholesterol. It functions as an anti-obesity and anti-diabetic agent, lowering the likelihood of haemorrhoids developing. Additionally, increasing face bulk and short-chain fatty acid synthesis improves gastrointestinal health and overall wellness. Baobab leaves had a moisture content of 6.4%, fat of 16.1%, ash of 3.2%, protein of 18.7%, carbohydrate 57.2% and crude fiber of 4.1%. The minerals determined in the sample of baobab leaves are Ca, Fe, Mg, K, Na, P, and Zn with Potassium (347.6±0.70) as the most abundant mineral while Zn (9.31±0.60) is the least abundant. The functional properties studied include pH, gelation temperature, bulk density, water absorption capacity, oil absorption capacity, foaming property, emulsifying property, and stability and swelling capacity, which are 8.72, 29, 0.39, 138, 98.20, 0.80, 72.80, and 73.50 respectively. The Fourier Transform InfraRed absorption spectra show bands like C=O, C-Cl and N-H. Baobab leaves are edible, nutritious, and non-toxic, as the mineral contents are within the required range.

Keywords: dietary fibre, proximate analysis, macronutrients, minerals, baobab leaves, frequency range

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Authors: Alaa El-Din Rezk

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For organic xenobiotics, sorption to Aldrich humic acid is a key process controlling their mobility, bioavailability, toxicity and fate in the soil. Hydrophobic organic compounds possessing either acid or basic groups can be partially ionized (deprotonated or protonated) within the range of natural soil pH. For neutral and ionogenicxenobiotics including (neutral, acids and bases) sorption coefficients normalized to organic carbon content, Koc, have measured at different pH values. To this end, the batch equilibrium technique has been used, employing SPME combined with GC-MSD as an analytical tool. For most ionogenic compounds, sorption has been affected by both pH and pKa and can be explained through Henderson-Hasselbalch equation. The results demonstrate that when assessing the environmental fate of ionogenic compounds, their pKa and speciation under natural conditions should be taken into account. A new model has developed to predict the relationship between log Koc and pH with full statistical evaluation against other existing predictive models. Neutral solutes have displayed a good fit with the classical model using log Kow as log Koc predictor, whereas acidic and basic compounds have displayed a good fit with the LSER approach and the new proposed model. Measurement limitations of the Batch technique and SPME-GC-MSD have been found with ionic compounds.

Keywords: humic acid, log Koc, pH, pKa, SPME-GCMSD

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Authors: Tibor Ajtai, Máté Pintér, Noémi Utry, Gergely Kiss-Albert, Andrea Palágyi, László Manczinger, Csaba Vágvölgyi, Gábor Szabó, Zoltán Bozóki

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According to the best knowledge of the authors, here we experimentally demonstrate first, a quantified correlation between the real-time measured optical feature of the ambient and the off-line measured toxicity data. Finally, using these correlations we are presenting a novel methodology for real time characterisation of ambient toxicity based on the multi wavelength aerosol phase photoacoustic measurement. Ambient carbonaceous particulate matter is one of the most intensively studied atmospheric constituent in climate science nowadays. Beyond their climatic impact, atmospheric soot also plays an important role as an air pollutant that harms human health. Moreover, according to the latest scientific assessments ambient soot is the second most important anthropogenic emission source, while in health aspect its being one of the most harmful atmospheric constituents as well. Despite of its importance, generally accepted standard methodology for the quantitative determination of ambient toxicology is not available yet. Dominantly, ambient toxicology measurement is based on the posterior analysis of filter accumulated aerosol with limited time resolution. Most of the toxicological studies are based on operational definitions using different measurement protocols therefore the comprehensive analysis of the existing data set is really limited in many cases. The situation is further complicated by the fact that even during its relatively short residence time the physicochemical features of the aerosol can be masked significantly by the actual ambient factors. Therefore, decreasing the time resolution of the existing methodology and developing real-time methodology for air quality monitoring are really actual issues in the air pollution research. During the last decades many experimental studies have verified that there is a relation between the chemical composition and the absorption feature quantified by Absorption Angström Exponent (AAE) of the carbonaceous particulate matter. Although the scientific community are in the common platform that the PhotoAcoustic Spectroscopy (PAS) is the only methodology that can measure the light absorption by aerosol with accurate and reliable way so far, the multi-wavelength PAS which are able to selectively characterise the wavelength dependency of absorption has become only available in the last decade. In this study, the first results of the intensive measurement campaign focusing the physicochemical and toxicological characterisation of ambient particulate matter are presented. Here we demonstrate the complete microphysical characterisation of winter time urban ambient including optical absorption and scattering as well as size distribution using our recently developed state of the art multi-wavelength photoacoustic instrument (4λ-PAS), integrating nephelometer (Aurora 3000) as well as single mobility particle sizer and optical particle counter (SMPS+C). Beyond this on-line characterisation of the ambient, we also demonstrate the results of the eco-, cyto- and genotoxicity measurements of ambient aerosol based on the posterior analysis of filter accumulated aerosol with 6h time resolution. We demonstrate a diurnal variation of toxicities and AAE data deduced directly from the multi-wavelength absorption measurement results.

Keywords: photoacoustic spectroscopy, absorption Angström exponent, toxicity, Ames-test

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Authors: Nader Ghareeb, Rüdiger Schmidt

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Minimizing the weight in flexible structures means reducing material and costs as well. However, these structures could become prone to vibrations. Attenuating these vibrations has become a pivotal engineering problem that shifted the focus of many research endeavors. One technique to do that is to design and implement an active control system. This system is mainly composed of a vibrating structure, a sensor to perceive the vibrations, an actuator to counteract the influence of disturbances, and finally a controller to generate the appropriate control signals. In this work, two different techniques are explored to create two different mathematical models of an active control system. The first model is a finite element model with a reduced number of nodes and it is called a super-element. The second model is in the form of state-space representation, i.e. a set of partial differential equations. The damping coefficients are calculated and incorporated into both models. The effectiveness of these models is demonstrated when the system is excited by its first natural frequency and an active control strategy is developed and implemented to attenuate the resulting vibrations. Results from both modeling techniques are presented and compared.

Keywords: damping coefficients, finite element analysis, super-element, state-space model

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Authors: Aylin Mohammadalipour Tofighi

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Marine-based geoengineering methods, proposed to mitigate climate change, operate primarily through two mechanisms: reducing atmospheric carbon dioxide levels and diminishing solar absorption by the oceans. While these approaches promise beneficial outcomes, they are fraught with environmental, legal, ethical, and political challenges, necessitating robust international governance. This paper underscores the critical role of international cooperation within the governance framework, offering a focused analysis of existing international environmental mechanisms applicable to marine-based geoengineering governance. It evaluates the efficacy and limitations of current international legal structures, including treaties and organizations, in managing marine-based geoengineering, noting significant gaps such as the absence of specific regulations, dedicated international entities, and explicit governance mechanisms such as monitoring. To rectify these problems, the paper advocates for concrete steps to bolster international cooperation. These include the formulation of dedicated marine-based geoengineering guidelines within international agreements, the establishment of specialized supervisory entities, and the promotion of transparent, global consensus-building. These recommendations aim to foster governance that is environmentally sustainable, ethically sound, and politically feasible, thereby enhancing knowledge exchange, spurring innovation, and advancing the development of marine-based geoengineering approaches. This study emphasizes the importance of collaborative approaches in managing the complexities of marine-based geoengineering, contributing significantly to the discourse on international environmental governance in the face of rapid climate and technological changes.

Keywords: climate change, environmental law, international cooperation, international governance, international law, marine-based geoengineering, marine law, regulatory frameworks

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Authors: K. Shahril, A. Nizam, M. Sabri, A. Siti Rohana, H. Salmah

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Chemical modifier (Acrylic Acid) is used as filler treatment to improve mechanical properties and swelling behavior of polypropylene/coconut fiber (PP/CF) composites by creating more adherent bonding between CF filler and PP Matrix. Treated (with chemical modifier) and untreated (without chemical modifier) composites were prepared in the formulation of 10 wt%, 20 wt%, 30 wt%, and 40 wt%. The mechanical testing indicates that composite with 10 wt% of untreated composite has the optimum value of tensile strength, and the composite with chemical modifier shows the tensile strength was increased. By increasing of filler loading, elastic modulus was increased while the elongation at brake was decreased. Meanwhile, the swelling test discerned that the increase of filler loading increased the water absorption of composites and the presence of chemical modifier reduced the equilibrium water absorption percentage.

Keywords: coconut fiber, polypropylene, acid acrylic, ethanol, chemical modifier, composites

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Authors: Rabinder Singh Bharj, Sandeep Kumar

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This investigation presents preparation of sample and analysis of results of ballistic impact test as per EN 1063 on the size, thickness, number, position, and type of the bonding interlayer Polyvinyl Butyral, Poly Carbonate and Poly Urethane on bullet proof glass. It was observed that impact energy absorbed by bullet proof glass increases with the increase of the total thickness from 33mm to 42mm to 51mm for all the three samples respectively. Absorption impact energy is greater for samples with more number of bonding interlayers than with the number of glass layers for uniform increase in total sample thickness. There is no effect on the absorption impact energy with the change in position of the bonding interlayer.

Keywords: absorbed energy, bullet proof glass, laminated glass, safety glass

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Authors: Christina Eleftheria Tzeliou, Demeter Tzeli

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Introduction: Molecular Logic Gates (MLGs) are molecular machines that can perform complex work, such as solving logic operations. Molecular switches, which are molecules that can experience chemical changes are examples of successful types of MLGs. Recently, Quintana-Romero and Ariza-Castolo studied experimentally six stable pseudo-hemi-indigo-derived MLGs capable of solving complex logic operations. The MLG design relies on a molecular switch that experiences Z and E isomerism, thus the molecular switch's axis has to be a double bond. The hemi-indigo structure was preferred for the assembly of molecular switches due to its interaction with visible light. Z and E pseudo-hemi-indigo isomers can also be utilized for selective isomerization as they have distinct absorption spectra. Methodology: Here, the photophysical properties of pseudo-hemi-indigo derivatives are examined, i.e., derivatives of molecule 1 with anthracene, naphthalene, phenanthrene, pyrene, and pyrrole. In conjunction with some trials that were conducted, the level of theory mentioned subsequently was determined. The structures under study were optimized in both cis and trans conformations at the PBE0/6-31G(d,p) level of theory. The absorption spectra of the structures were calculated at PBE0/DEF2TZVP. In all cases, the absorption spectra of the studied systems were calculated including up to 50 singlet- and triplet-spin excited electronic states. Transition states (cis → cis, cis → trans, and trans → trans) were obtained in cases where it was possible, with PBE0/6-31G(d,p) for the optimization of the transition states and PBE0/DEF2TZVP for the respective absorption spectra. Emission spectra were obtained for the first singlet state of each molecule in cis both and trans conformations in PBE0/DEF2TZVP as well. All studies were performed in chloroform solvent that was added as a dielectric constant and the polarizable continuum model was also employed. Findings: Shifts of up to 25 nm are observed in the absorption spectra due to cis-trans isomerization, while the transition state is shifted up to about 150 nm. The electron density distribution is also examined, where charge transfer and electron transfer phenomena are observed regarding the three excitations of interest, i.e., H-1 → L, H → L and H → L+1. Emission spectra calculations were also carried out at PBE0/DEF2TZVP for the complete investigation of these molecules. Using protonation as input, selected molecules act as MLGs. Conclusion: Theoretical data so far indicate that both cis-trans isomerization, and cis-cis and trans-trans conformer isomerization affect the UV-visible absorption and emission spectra. Specifically, shifts of up to 30 nm are observed, while the transition state is shifted up to about 150 nm in cis-cis isomerization. The computational data obtained are in agreement with available experimental data, which have predicted that the pyrrole derivative is a MLG at 445 nm and 400 nm using protonation as input, while the anthracene derivative is a MLG that operates at 445 nm using protonation as input. Finally, it was found that selected molecules are candidates as MLG using protonation and light as inputs. These MLGs could be used as chemical sensors or as particular intracellular indicators, among several other applications. Acknowledgements: The author acknowledges the Hellenic Foundation for Research and Innovation for the financial support of this project (Fellowship Number: 21006).

Keywords: absorption spectra, DFT calculations, isomerization, molecular logic gates

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Authors: Dalila Hocine, Mohammed Said Belkaid, Abderahmane Moussi

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In this study, pure rutile TiO2 thin films were directly synthesized on silicon substrates by Atmospheric Pressure Chemical Vapor Deposition technique (APCVD) using TiCl4 as precursor. We studied the physicochemical properties and the optical properties of the produced coatings by means of standard characterization techniques of Fourier Transform Infrared Spectroscopy (FTIR) combined with UV-Vis Reflectance Spectrophotometry. The absorption peaks at 423 cm-1 and 610 cm-1 were observed for the rutile TiO2 thin films, by FTIR measurements. The absorption peak at 739 cm-1 due to the vibration of the Ti-O bonds, was also detected. UV-Vis Reflectance Spectrophotometry is employed for measuring the optical band gap from the measurements of the TiO2 films reflectance. The optical band gap was then extracted from the reflectance data for the TiO2 sample. It was estimated to be 3.05 eV which agrees with the band gap of commercial rutile TiO2 sample.

Keywords: titanium dioxide, physicochemical properties, APCVD, FTIR, band gap

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Authors: Der Chyan Lin

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Since the early introduction by Ormondroyd and Den Hartog, vibration absorber (VA) has become one of the most commonly used vibration mitigation strategies. The strategy is most effective for a primary plant subjected to a single frequency excitation. For continuous systems, notable advances in vibration absorption in the multi-frequency system were made. However, the efficacy of the VA strategy for systems under multi-frequency excitation is not well understood. For example, for an N degrees-of-freedom (DOF) primary-absorber system, there are N 'peak' frequencies of large amplitude vibration per every new excitation frequency. In general, the usable range for vibration absorption can be greatly reduced as a result. Frequency modulated harmonic excitation is a commonly seen multi-frequency excitation example: f(t) = cos(ϖ(t)t) where ϖ(t)=ω(1+α sin⁡(δt)). It is known that f(t) has a series expansion given by the Bessel function of the first kind, which implies an infinity of forcing frequencies in the frequency modulated harmonic excitation. For an SDOF system of natural frequency ωₙ subjected to f(t), it can be shown that amplitude peaks emerge at ω₍ₚ,ₖ₎=(ωₙ ± 2kδ)/(α ∓ 1),k∈Z; i.e., there is an infinity of resonant frequencies ω₍ₚ,ₖ₎, k∈Z, making the use of VA strategy ineffective. In this work, we propose an absorber frequency placement strategy for SDOF vibration systems subjected to frequency-modulated excitation. An SDOF linear mass-spring system coupled to lateral absorber systems is used to demonstrate the ideas. Although the mechanical components are linear, the governing equations for the coupled system are nonlinear. We show using N identical absorbers, for N ≫ 1, that (a) there is a cluster of N+1 natural frequencies around every natural absorber frequency, and (b) the absorber frequencies can be moved away from the plant's resonance frequency (ω₀) as N increases. Moreover, we also show the bandwidth of the VA performance increases with N. The derivations of the clustering and bandwidth widening effect will be given, and the superiority of the proposed strategy will be demonstrated via numerical experiments.

Keywords: Bessel function, bandwidth, frequency modulated excitation, vibration absorber

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Authors: Veriko Jeladze, Besarion Partsvania, Levan Shoshiashvili

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This paper addresses a very topical issue today. The frequency range 2.5-100 GHz contains frequencies that have already been used or will be used in modern 5G technologies. The wavelengths used in 5G systems will be close to the body dimensions of small size biological objects, particularly insects. Because the body and body parts dimensions of insects at these frequencies are comparable with the wavelength, the high absorption of EMF energy in the body tissues can occur(body resonance) and therefore can cause harmful effects, possibly the extinction of some of them. An investigation into the impact of radio-frequency nonionizing electromagnetic field (EMF) utilized in the future 5G on insects is of great importance as a very high number of 5G network components will increase the total EMF exposure in the environment. All ecosystems of the earth are interconnected. If one component of an ecosystem is disrupted, the whole system will be affected (which could cause cascading effects). The study of these problems is an important challenge for scientists today because the existing studies are incomplete and insufficient. Consequently, the purpose of this proposed research is to investigate the possible hazardous impact of RF-EMFs (including 5G EMFs) on insects. The project will study the effects of these EMFs on various insects that have different body sizes through computer modeling at frequencies from 2.5 to 100 GHz. The selected insects are honey bee, wasp, and ladybug. For this purpose, the detailed 3D discrete models of insects are created for EM and thermal modeling through FDTD and will be evaluated whole-body Specific Absorption Rates (SAR) at selected frequencies. All these studies represent a novelty. The proposed study will promote new investigations about the bio-effects of 5G-EMFs and will contribute to the harmonization of safe exposure levels and frequencies of 5G-EMFs'.

Keywords: electromagnetic field, insect, FDTD, specific absorption rate (SAR)

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Authors: Md. Moinul Islam, N. M. Golam Zakaria

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Seakeeping analysis of catamaran vessels in the earlier stages of design has become an important issue as it dictates the seakeeping characteristics, and it ensures safe navigation during the voyage. In the present paper, a 3D numerical method for the seakeeping prediction of catamaran vessel is presented using the 3D Green Function method. Both steady and unsteady potential flow problem is dealt with here. Using 3D linearized potential theory, the dynamic wave loads and the subsequent response of the vessel is computed. For validation of the numerical procedure catamaran vessel composed of twin, Wigley form demi-hull is used. The results of the present calculation are compared with the available experimental data and also with other calculations. The numerical procedure is also carried out for NPL-based round bilge catamaran, and hydrodynamic coefficients along with heave and pitch motion responses are presented for various Froude number. The results obtained by the present numerical method are found to be in fairly good agreement with the available data. This can be used as a design tool for predicting the seakeeping behavior of catamaran ships in waves.

Keywords: catamaran, hydrodynamic coefficients , motion response, 3D green function

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Authors: Y. H. Hwang, J. Won, Y. S. Kang

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Supported ionic liquid membranes (SILMs) have attracted due to the negligible vapor pressure of ionic liquids (ILs) as well as the high gas selectivity for specific gases such as CO2 or olefin. 1-ethyl-3-methylimidazolium tricyanomethanide ([EMIM][TCM]), 1-butyl-3-methylimidazolium tricyanomethanide ([BMIM][TCM]), show high CO2 solubility, CO2 absorption, rapid CO2 absorption rate and negligible vapor pressure, SILMs using these ILs have been good candidates as CO2 separation membranes. However, SILM has to be operated at a low differential pressure to prevent the solvent from being expelled from the pores of supported membranes. In this paper, we improve the mechanical strength by forming ion gels which provide the stability while it retains the diffusion properties of the liquid stage which affects the gas separation properties. The ion gel was created by the addition of tri-block copolymer, poly(styrene-ethylene oxide-b-styrene) in RTIL. SILM using five different RTILs, are investigated with and without ion gels. The gas permeance were measured and the gas performance with and without the SEOS were investigated.

Keywords: ion gel, ionic liquid, membrane, nanostructure

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Authors: Ghaem Zamani, Farveh Aghaye Nezhad, Amin Barari

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The installation process of caissons has usually been a challenging step in the design phase, especially in the case of suction-assisted installation. The engineering practice for estimating the caisson penetration resistance is primarily controlled by the resistance governed by inner and outer skirt friction and the tip resistance. Different methods have been proposed in the literature to evaluate the above components, while the CPT-based methodology has attained notable popularity among others. In this method, two empirical coefficients are suggested, k𝒻 and kp, which relate the frictional resistance and tip resistance to the cone penetration resistance (q𝒸), respectively. A series of jacking installation and uninstallation experiments for different soil densities were carried out in the offshore geotechnical laboratory of Aalborg University, Denmark. The main goal of these tests was to find appropriate values for empirical coefficients of the CPT-based method for the buckets with large embedment ratio (i.e., d/D=1, where d is the skirt length and D is the diameter) and increased tip area penetrated into dense sand deposits. The friction resistance effects were isolated during the pullout experiments; hence, the k𝒻 was back-measured from the tests in the absence of tip resistance. The actuator force during jacking installation equals the sum of frictional resistance and tip resistance. Therefore, the tip resistance of the bucket is calculated by subtracting the back-measured frictional resistance from penetration resistance; hence the relevant coefficient kp would be achieved. The cone penetration test was operated at different points before and after each installation attempt to measure the cone penetration resistance (q𝒸), and the average value of q𝒸 is used for calculations. The experimental results of the jacking installation tests indicated that a larger friction area considerably increased the penetration resistance; however, this effect was completely diminished when foundation suction-assisted penetration was used. Finally, the values measured for the empirical coefficient of the CPT-based method are compared with the highest expected and most probable values suggested by DNV(1992) for uniform thickness buckets.

Keywords: suction caisson, offshore geotechnics, cone penetration test, wind turbine foundation

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Authors: Razieh Shamsi, Mehdi Faezipour, Ali Abdolkhani

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In this research, the characteristics of composites prepared from waste silk fibers and recycled polycarbonate polymer (used compacted boards) at four levels of 0, 10, 20, and 30% (silk fibers) and using 2% N- 2-Aminoethyl-3-Aminopropyltrimethoxysilane was investigated as a coupling agent and melt process method. Silk fibers (carpet weaving waste) with dimensions of 8-18 mm were prepared, and recycled polymer with 9 mesh grading was ground. Production boards in 3 thicknesses, 3 mm (tensile test samples), 5 mm (bending test samples, water absorption, and thickness shrinkage), 7 mm (impact resistance test samples) ) with a specific weight of 1 gram per cubic centimeter, hot pressing time and temperature of 12 minutes and 190 degrees Celsius with a pressure of 130 bar, cold pressing time of 6 minutes with a pressure of 50 bar and using the coupling agent N- (2- Aminoethyl)-3-aminopropyltrimethoxysilane was prepared in a constant amount of 2% of the dry weight of the filler. The results showed that, in general, by adding silk fibers to the base polymer, compared to the control samples (pure recycled polycarbonate polymer) and also by increasing the amount of silk fibers, almost all the resistances increased. The amount of water absorption of the constructed composite increased with the increase in the amount of silk fibers, and the thickness absorption was equal to 0% even after 72 hours of immersion in water. The thermal resistance of the pure recycled polymer was higher than the prepared composites, and by adding silk fibers to the base polymer and also by increasing the amount of silk fibers from 10 to 30%, the thermal resistance of the composites decreased.

Keywords: wood composite, recycled polycarbonate, silk fibers, polymer

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Authors: Santanu Chattopadhyay, Gautam Sarkar, Arabinda Das

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This paper presents wavelet based classification of various heart diseases. Electrocardiogram signals of different heart patients have been studied. Statistical natures of electrocardiogram signals for different heart diseases have been compared with the statistical nature of electrocardiograms for normal persons. Under this study four different heart diseases have been considered as follows: Myocardial Ischemia (MI), Congestive Heart Failure (CHF), Arrhythmia and Sleep Apnea. Statistical nature of electrocardiograms for each case has been considered in terms of kurtosis values of two types of wavelet coefficients: approximate and detail. Nine wavelet decomposition levels have been considered in each case. Kurtosis corresponding to both approximate and detail coefficients has been considered for decomposition level one to decomposition level nine. Based on significant difference, few decomposition levels have been chosen and then used for classification.

Keywords: arrhythmia, congestive heart failure, discrete wavelet transform, electrocardiogram, myocardial ischemia, sleep apnea

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Authors: Badreddine Chemali, Boualem Tiliouine

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This article presents the main results of a numerical investigation on the uncertainty of dynamic response of structures with statistically correlated random damping Gamma distributed. A computational method based on a Linear Statistical Model (LSM) is implemented to predict second order statistics for the response of a typical industrial building structure. The significance of random damping with correlated parameters and its implications on the sensitivity of structural peak response in the neighborhood of a resonant frequency are discussed in light of considerable ranges of damping uncertainties and correlation coefficients. The results are compared to those generated using Monte Carlo simulation techniques. The numerical results obtained show the importance of damping uncertainty and statistical correlation of damping coefficients when obtaining accurate probabilistic estimates of dynamic response of structures. Furthermore, the effectiveness of the LSM model to efficiently predict uncertainty propagation for structural dynamic problems with correlated damping parameters is demonstrated.

Keywords: correlated random damping, linear statistical model, Monte Carlo simulation, uncertainty of dynamic response

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Authors: Ufuk Aydın

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The Coda attenuation and frequency dependency of seismic wave are strongly dependent on the effective stresses structures within the upper crust. In this study, the data of three different stations were used to examine the lateral variation of stress. The tectonic structures of these three areas have been examined comparatively using lateral coda tomography. In the study using the single scatter method, the window length selected to be 20 second. Coda values 80 with 94 and frequency dependency values obtained between 0.69 and 1.21. The 1/QC values for the three regions ranged from 0.0012 to 0.017, highlighting the regional differences in the seismotectonic activity of the crust. The lowest absorption values obtained from Erzurum station when the highest absorption values obtained at the Kemaliye station. The low Qc and high frequency dependency values obtained Kemaliye, which indicates that it has highest tectonic activity than other two regions. The seismo-dynamics data obtained from the study found to be in agreement with the tectonic structure of the region.

Keywords: regional coda attenuation, tectonic stress, crustal deformation

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Authors: Vincent Kheswa

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X-rays are ionizing electromagnetic radiation that is used in various industries such as computed tomography scans, dental X-rays, and screening freight trains. However, they pose health risks to humans if they are not shielded properly. In recent years, many researchers around the globe have been searching for nontoxic best possible glass materials for shielding X-rays. In this work, the x-ray shielding properties of 45Na₂O + 10 Bi₂O₃ + (5 - x)TiO₂+ (x) Nb₂O₅ + 40 P₂O₅, were x = 0, 1, 3, 5 mol%, glass materials were studied. The results revealed that the glass sample with the highest TiO2 content has the highest mass and linear attenuation coefficients and lowest half-value thickness, tenth-value thickness and mean-free path in the 20 to 80 keV energy region. The sample with 3 mol% of Nb₂O₅ has the highest mass and linear attenuation coefficients and the lowest half-value thickness, tenth-value thickness, and mean-free path at 15 keV and photon energies between 80 to 300 keV. It was, therefore, concluded that 45Na₂O + 10 Bi₂O₃ + 5 TiO₂ + 40 P₂O₅ glass is best for shielding x-rays of energies between 20 and 80 keV, while 45Na₂O + 10 Bi₂O₃ + 2 TiO₂ + 3 Nb₂O₅ + 40 P₂O₅ is best for shielding 15 keV x-rays and x-rays of energies between 80 keV and 300 keV.

Keywords: bismuth-titanium-phosphate glass, x-ray shielding, LAC, MAC, radiation shielding

Procedia PDF Downloads 59

Authors: Zhihui Liu, Dongmei Hao, Qian Qiu, Yang An, Lin Yang, Song Zhang, Yimin Yang, Xuwen Li, Dingchang Zheng

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Premature birth, defined as birth before 37 completed weeks of gestation is a leading cause of neonatal morbidity and mortality and has long-term adverse consequences for health. It has recently been reported that the worldwide preterm birth rate is around 10%. The existing measurement techniques for diagnosing preterm delivery include tocodynamometer, ultrasound and fetal fibronectin. However, they are subjective, or suffer from high measurement variability and inaccurate diagnosis and prediction of preterm labor. Electrohysterography (EHG) method based on recording of uterine electrical activity by electrodes attached to maternal abdomen, is a promising method to assess uterine activity and diagnose preterm labor. The purpose of this study is to analyze the difference of EHG signal features between term labor and preterm labor. Free access database was used with 300 signals acquired in two groups of pregnant women who delivered at term (262 cases) and preterm (38 cases). Among them, EHG signals from 38 term labor and 38 preterm labor were preprocessed with band-pass Butterworth filters of 0.08–4Hz. Then, EHG signal features were extracted, which comprised classical time domain description including root mean square and zero-crossing number, spectral parameters including peak frequency, mean frequency and median frequency, wavelet packet coefficients, autoregression (AR) model coefficients, and nonlinear measures including maximal Lyapunov exponent, sample entropy and correlation dimension. Their statistical significance for recognition of two groups of recordings was provided. The results showed that mean frequency of preterm labor was significantly smaller than term labor (p < 0.05). 5 coefficients of AR model showed significant difference between term labor and preterm labor. The maximal Lyapunov exponent of early preterm (time of recording < the 26th week of gestation) was significantly smaller than early term. The sample entropy of late preterm (time of recording > the 26th week of gestation) was significantly smaller than late term. There was no significant difference for other features between the term labor and preterm labor groups. Any future work regarding classification should therefore focus on using multiple techniques, with the mean frequency, AR coefficients, maximal Lyapunov exponent and the sample entropy being among the prime candidates. Even if these methods are not yet useful for clinical practice, they do bring the most promising indicators for the preterm labor.

Keywords: electrohysterogram, feature, preterm labor, term labor

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Authors: Redouane Lombarkia

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To apply a new material model developed and validated for plain weave fabric CFRP composites usually used in stanchions in sub-cargo section in aircrafts. This work deals with the development of a numerical model of the fuselage section of commercial aircraft based on the pure explicit finite element method FEM within Abaqus/Explicit commercial code. The aim of this work is the evaluation of the energy absorption capabilities of a full-scale composite fuselage section, including sub-cargo stanchions, Drop tests were carried out from a free fall height of about 5 m and impact velocity of about 6 m∕s. To asses, the prediction efficiency of the proposed numerical modeling procedure, a comparison with literature existed experimental results was performed. We demonstrate the efficiency of the proposed methodology to well capture crash damage mechanisms compared to experimental results

Keywords: crashworthiness, fuselage section, finite elements method (FEM), stanchions, specific energy absorption SEA

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Authors: Spandan Sahu, Amiya Kumar Pati, Kishanjit Kumar Khatua

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Rivers are the backbone of human civilization as well as one of the most important components of nature. In this paper, a method for predicting lateral depth-averaged velocity distribution in a two-flow braided compound channel is proposed. Experiments were conducted to study the boundary shear stress in the tip of the two flow path. The cross-section of the channel is divided into several panels to study the flow phenomenon on both the main channel and the flood plain. It can be inferred from the study that the flow coefficients get affected by boundary shear stress. In this study, the analytical solution of Shiono and knight (SKM) for lateral distributions of depth-averaged velocity and bed shear stress has been taken into account. The SKM is based on hydraulic parameters, which signify the bed friction factor (f), lateral eddy viscosity, and depth-averaged flow. While applying the SKM to different panels, the equations are solved considering the boundary conditions between panels. The boundary shear stress data, which are obtained from experimentation, are compared with CES software, which is based on quasi-one-dimensional Reynold's Averaged Navier-Stokes (RANS) approach.

Keywords: boundary shear stress, lateral depth-averaged velocity, two-flow braided compound channel, velocity distribution

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Authors: Benmalek M. Larbi, R. Harbi, S. Boukor

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This paper reports an experimental work that aimed to investigate the effects of clay brick waste, as part of fine aggregate, on rendering mortar performance. The brick, in crushed form, was from a local brick manufacturer that was rejected due to being of-standard. It was used to replace 33.33 %, 50 %, 66.66 % and 100 % by weight of the quarry sand in mortar. Effects of the brick replacement on the mortar key properties intended for wall plastering were investigated; these are workability, compressive strength, flexural strength, linear shrinkage, water absorption by total immersion and by capillary suction. The results showed that as the brick replacement level increased, the mortar workability reduced. The linear shrinkage increases over time and decreases with the introduction of brick waste. The compressive and flexural strengths decrease with the increase of brick waste because of their great water absorption.

Keywords: clay brick waste, mortar, properties, quarry sand

Procedia PDF Downloads 262

Authors: U. Gunal, H. I. Turgut, H. Gurler, S. Kaya

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There are many ever-increasing and newly emerging problems with rapid population growth in the world. With the increase in people's quality of life in our daily life, acoustic comfort has become an important feature in the textile industry. In order to meet all these expectations in people's comfort areas and survive in challenging competitive conditions in the market without compromising the customer product quality expectations of textile manufacturers, it has become a necessity to bring functionality to the products. It is inevitable to research and develop materials and processes that will bring these functionalities to textile products. The noise we encounter almost everywhere in our daily life, in the street, at home and work, is one of the problems which textile industry is working on. It brings with it many health problems, both mentally and physically. Therefore, noise control studies become more of an issue. Besides, materials used in noise control are not sufficient to reduce the effect of the noise level. The fabrics used in acoustic studies in the textile industry do not show sufficient performance according to their weight and high cost. Thus, acoustic textile products can not be used in daily life. In the thesis study, the attributions used in the noise control and building acoustics studies in the literature were analyzed, and the product with the highest damping value that a textile material will have was designed, manufactured, and tested. Optimum values were obtained by using different material samples that may affect the performance of the acoustic material. Acoustic measurement methods should be applied to verify the acoustic performances shown by the parameters and the designed three-dimensional structure at different values. In the measurements made in the study, the device designed for determining the acoustic performance of the material for both the impedance tube according to the relevant standards and the different noise types in the study was used. In addition, sound records of noise types encountered in daily life are taken and applied to the acoustic absorbent fabric with the aid of the device, and the feasibility of the results and the commercial ability of the product are examined. MATLAB numerical computing programming language and libraries were used in the frequency and sound power analyses made in the study.

Keywords: acoustic, egg crate, fabric, textile

Procedia PDF Downloads 108