scholarly journals Acoustic Characterization of Some Steel Industry Waste Materials

2021 ◽  
Vol 11 (13) ◽  
pp. 5924
Author(s):  
Elisa Levi ◽  
Simona Sgarbi ◽  
Edoardo Alessio Piana
Keyword(s):  
Thermal Characteristic ◽  
Environmental Benefits ◽  
Acoustic Properties ◽  
Physical Parameters ◽  
Industry Waste ◽  
Acoustic Characterization ◽  
Minimization Procedure ◽  
The Difference ◽  
By Products

From a circular economy perspective, the acoustic characterization of steelwork by-products is a topic worth investigating, especially because little or no literature can be found on this subject. The possibility to reuse and add value to a large amount of this kind of waste material can lead to significant economic and environmental benefits. Once properly analyzed and optimized, these by-products can become a valuable alternative to conventional materials for noise control applications. The main acoustic properties of these materials can be investigated by means of a four-microphone impedance tube. Through an inverse technique, it is then possible to derive some non-acoustic properties of interest, useful to physically characterize the structure of the materials. The inverse method adopted in this paper is founded on the Johnson–Champoux–Allard model and uses a standard minimization procedure based on the difference between the sound absorption coefficients obtained experimentally and predicted by the Johnson–Champoux–Allard model. The results obtained are consistent with other literature data for similar materials. The knowledge of the physical parameters retrieved applying this technique (porosity, airflow resistivity, tortuosity, viscous and thermal characteristic length) is fundamental for the acoustic optimization of the porous materials in the case of future applications.

scholarly journals Predicting Compression Pressure of Knitted Fabric Using a Modified Laplace’s Law

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4461
Author(s):  
Yetanawork Teyeme ◽  
Benny Malengier ◽  
Tamrat Tesfaye ◽  
Simona Vasile ◽  
Wolelaw Endalew ◽  
...  
Keyword(s):  
Physical Parameters ◽  
Interface Pressure ◽  
Compression Pressure ◽  
Engineering Strain ◽  
Measuring Device ◽  
Laplace’S Law ◽  
The Difference ◽  
Experimental Pressure ◽  
Laplace's Law

The aim of this study is to develop a mathematical model for the prediction of compression pressure based on fabric parameters, such as engineering stress, engineering strain and engineering modulus of elasticity. Four knitted compression fabrics with different fibrous compositions and knit structures were used. Rectangular-cut strips were employed for the force–elongation characterization of the fabrics. The experimental pressure values between the fabric and rigid cylinder were assessed using a Picopress pressure measuring device. The mechanical and physical parameters of the fabric that influence the interface pressure, such as strain, elasticity modulus/stress and thickness, were determined and integrated into Laplace’s law. A good correlation was observed between the experimental and calculated pressure values for all combinations of fabrics, mounted with variable tension on the cylinder. Over the considered range of pressures, the difference between the two datasets was generally less than 0.5 mmHg. The effect of washing after five, ten and fifteen washing cycles on the fabric–cylinder interface pressure was found to be significant.

Acoustic Characterization of Automotive Mufflers - Part I: Test Rig Design and Evaluation of Acoustic Properties

2012 ◽  
Author(s):  
Giovanni Ferrara ◽  
Lorenzo ferrari ◽  
Giovanni Vichi ◽  
Giulio Lenzi ◽  
Davide Biliotti
Keyword(s):  
Acoustic Properties ◽  
Test Rig ◽  
Acoustic Characterization

Analisis Karakterisasi Teknologi Direct Sequence Spread Spectrum Dan Frequency Hopping Spread Spectrum

2019 ◽  
Vol 2 (2) ◽  
pp. 129-138
Author(s):  
Fawzan Galib Abdul Karim Bawahab ◽  
Elvan Yuniarti ◽  
Edi Kurniawan
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Multiple Access ◽  
Frequency Hopping ◽  
Direct Sequence Spread Spectrum ◽  
Direct Sequence ◽  
Frequency Hopping Spread Spectrum ◽  
Two Systems ◽  
The Difference

Abstrak. Pada penelitian ini, telah dilakukan analisa karakterisasi pada teknologi Direct Sequence Spread Spectrum dan Frequency Hopping Spread Spectrum, sebagai salah satu teknik multiple-access pada sistem komunikasi. Karakterisasi dilakukan untuk mencari bagaimana cara meningkatkan keoptimalan kedua sistem tersebut, dalam mengatasi masalah interferensi dengan sistem dan channel yang sama. Dan juga untuk menentukan veriabel apa yang mempengaruhi keoptimalan kedua sistem tersebut. Karakterisasi dilakukan dengan menentukan variabel-variabel yang mempengaruhi keoptimalan keduanya. Hasil dari karakterisasi, diketahui variabel-variabel yang mempengaruhi kemampuan sistem DSSS yaitu nilai frekuensi spreading (). Sedangkan untuk sistem FHSS yaitu nilai frekuensi spreading ( dan ) dan selisih antara frekuensi hopping data dengan frekuensi hopping interferensi . Kata Kunci: BER, DSSS, FHSS, Interference, Spread spectrum. Abstract. In this study, characterization of Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum technologies have been done, as one of the multiple-access techniques in communication systems. Characterization is done to find out how to improve the ability of the two systems, in solving interference problems with the same system and channel. And also to determine what veriabel affects the ability of the two systems. Characterization is done by determining the variables that affect the ability of both. The results of the characterization, known variables that affect the ability of the DSSS system are the spreading frequency value (). As for the FHSS system, the spreading frequency value ( and ) and the difference between frequency hopping data with frequency hopping interference .

Acoustic Characterization of Marine Sediments

1997 ◽  
Author(s):  
Anatoliy N. Ivakin ◽  
Darrell R. Jackson
Keyword(s):  
Marine Sediments ◽  
Acoustic Characterization

Characterization of the surface of hydrodesulphurization catalysts by adsorption of hydrocarbons

1984 ◽  
Vol 49 (2) ◽  
pp. 410-420
Author(s):  
Eva Hillerová ◽  
Miroslav Zdražil
Keyword(s):  
Hydrogen Sulphide ◽  
Chromatographic Method ◽  
Supported Catalysts ◽  
Alumina Surface ◽  
Reversible Adsorption ◽  
The Difference

Reversible adsorption of heptane and benzene on model and industrial hydrodesulphurization molybdena catalysts has been studied by elution chromatographic method at 150 °C. An increase in the adsorption of heptane on sulphidation of adsorbents was small for Al2O3 and great for MoO3. Supported catalysts behaved as mixture of Al2O3 and MoO3.The portion of surface which can be transformed by sulphidation into MoS2 ranged from 0 to 65% for individual commercial catalysts, as determined from the change in heptane adsorption after sulphidation of a given sample. The polarity of catalysts, including their acidity, was estimated from the difference between adsorption of benzene and heptane. The polarity of model and industrial catalysts in oxidic form was similar to that of alumina in most cases. The decrease in the polarity after sulphidation of the adsorbents was small for Al2O3 and great for MoO3. The decrease in polarity resulting from sulphidation of supported catalysts was relatively small, since the reaction of MoO3 monolayer with hydrogen sulphide leads to partial reformation of the alumina surface. The acidity of supported sulphided hydrodesulphurization catalysts has been shown by this method to be comparable with the acidity of the support itself.

scholarly journals Nonlinear stability of two-layer shallow water flows with a free surface

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190594
Author(s):  
Francisco de Melo Viríssimo ◽  
Paul A. Milewski
Keyword(s):  
Free Surface ◽  
Initial Data ◽  
Nonlinear Stability ◽  
Mathematical Proof ◽  
Passive Layer ◽  
Physical Parameters ◽  
Immiscible Fluid ◽  
Dimensional System ◽  
The Cauchy Problem ◽  
The Difference

The problem of two layers of immiscible fluid, bordered above by an unbounded layer of passive fluid and below by a flat bed, is formulated and discussed. The resulting equations are given by a first-order, four-dimensional system of PDEs of mixed-type. The relevant physical parameters in the problem are presented and used to write the equations in a non-dimensional form. The conservation laws for the problem, which are known to be only six, are explicitly written and discussed in both non-Boussinesq and Boussinesq cases. Both dynamics and nonlinear stability of the Cauchy problem are discussed, with focus on the case where the upper unbounded passive layer has zero density, also called the free surface case. We prove that the stability of a solution depends only on two ‘baroclinic’ parameters (the shear and the difference of layer thickness, the former being the most important one) and give a precise criterion for the system to be well-posed. It is also numerically shown that the system is nonlinearly unstable, as hyperbolic initial data evolves into the elliptic region before the formation of shocks. We also discuss the use of simple waves as a tool to bound solutions and preventing a hyperbolic initial data to become elliptic and use this idea to give a mathematical proof for the nonlinear instability.

Synthesis and characterization of a series of 1-methyl-4-[2-aryl-1-diazenyl]piperazines and a series of ethyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates

2004 ◽  
Vol 82 (8) ◽  
pp. 1294-1303 ◽  
Author(s):  
Vanessa Renée Little ◽  
Keith Vaughan
Keyword(s):  
Free Energy ◽  
Chemical Shifts ◽  
Linear Free Energy Relationship ◽  
Piperazine Ring ◽  
Linear Free Energy ◽  
In Series ◽  
Methylene Groups ◽  
Diazonium Coupling ◽  
The Difference

1-Methylpiperazine was coupled with a series of diazonium salts to afford the 1-methyl-4-[2-aryl-1-diazenyl]piperazines (2), a new series of triazenes, which have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. Assignment of the chemical shifts to specific protons and carbons in the piperazine ring was facilitated by comparison with the chemical shifts in the model compounds piperazine and 1-methylpiperazine and by a HETCOR experiment with the p-tolyl derivative (2i). A DEPT experiment with 1-methylpiperazine (6) was necessary to distinguish the methyl and methylene groups in 6, and a HETCOR spectrum of 6 enabled the correlation of proton and carbon chemical shifts. Line broadening of the signals from the ring methylene protons is attributed to restricted rotation around the N2-N3 bond of the triazene moiety in 2. The second series of triazenes, the ethyl 4-[2-phenyl-1-diazenyl]-1-piperazinecarboxylates (3), have been prepared by similar diazonium coupling to ethyl 1-piperazinecarboxylate and were similarly characterized. The chemical shifts of the piperazine ring protons are much closer together in series 3 than in series 2, resulting in distortion of the multiplets for these methylenes. It was noticed that the difference between these chemical shifts in 3 exhibited a linear free energy relationship with the Hammett substituent constants for the substituents in the aryl ring. Key words: triazene, piperazine, diazonium coupling, NMR, HETCOR, linear free energy relationship.

scholarly journals Valorization of food industry waste and by-products using 3D printing: A study on the development of value-added functional cookies

Future Foods ◽  
2021 ◽  
pp. 100036
Author(s):  
Bhagya Jagadiswaran ◽  
Vishvaa Alagarasan ◽  
Priyadharshini Palanivelu ◽  
Radhika Theagarajan ◽  
J.A. Moses ◽  
...  
Keyword(s):  
3D Printing ◽  
Food Industry ◽  
Value Added ◽  
Industry Waste ◽  
Food Industry Waste ◽  
By Products

scholarly journals Analytical Characterization of Water-Soluble Constituents in Olive-Derived By-Products

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1299
Author(s):  
Pablo Doménech ◽  
Aleta Duque ◽  
Isabel Higueras ◽  
José Luis Fernández ◽  
Paloma Manzanares
Keyword(s):  
Olive Tree ◽  
Mediterranean Area ◽  
Water Soluble ◽  
Olive Pomace ◽  
Olive Leaves ◽  
Olive Stone ◽  
Olive Trees ◽  
Tree Pruning ◽  
By Products

Olive trees constitute one of the largest agroindustries in the Mediterranean area, and their cultivation generates a diverse pool of biomass by-products such as olive tree pruning (OTP), olive leaves (OL), olive stone (OS), and extracted olive pomace (EOP). These lignocellulosic materials have varying compositions and potential utilization strategies within a biorefinery context. The aim of this work was to carry out an integral analysis of the aqueous extractives fraction of these biomasses. Several analytical methods were applied in order to fully characterize this fraction to varying extents: a mass closure of >80% was reached for EOP, >76% for OTP, >65% for OS, and >52% for OL. Among the compounds detected, xylooligosaccharides, mannitol, 3,4-dihydroxyphenylglycol, and hydroxytyrosol were noted as potential enhancers of the valorization of said by-products. The extraction of these compounds is expected to be more favorable for OTP, OL, and EOP, given their high extractives content, and is compatible with other utilization strategies such as the bioconversion of the lignocellulosic fraction into biofuels and bioproducts.

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