Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 129 for “"Absorption coefficient"”.
-
Application of cepstral techniques to the automated determination of the sound power absorption coefficient
… of using cepstral analysis to determine the absorption coefficient of elastic porous materials. Jongens, in his Masters thesis, applied this technique to determine the absorption coefficient of asphalt samples mounted in a sample holder at the end of a tube. Jongens and others identified …
-
A Wide Band Model for the Absorption Coefficient Cumulative Distribution Function of Water Vapor and Carbon Dioxide
… results. The explicit formulation of the absorption coefficient in terms of the wide band cumulative distribution function represents an efficient and accurate method for use in complex radiative transport problems.
-
Application of cepstral signal processing techniques and a guard tube to the in-situ measurement of the normal incidence sound absorption coefficient
… measurement of the normal incidence sound power absorption coefficient of homogenous materials. The work stemmed from an International Standards Organisation (ISO) working group, ISO/TC 43/SCJ WG38, tasked to formulate a new international standard: " Procedure for measuring sound absorption …
-
Application of cepstrum techniques and a guard tube to the measurement of the normal incident sound power absorption coefficient of road surfaces in-situ
… that was to measure the plane wave sound power absorption coefficient of road surfaces in-situ. Road traffic noise has been identified as the greatest noise pollutant in the industrialised world with the tyre/road interaction being the major source of noise for traffic speeds in excess of 50 …
-
The effect of repetitive firing cycles on physical and optical properties of zirconia reinforced lithium silicate ceramics
… cycles’ effects on the translucency, light’s absorption coefficient, and flexural strength of zirconia-reinforced lithium silicate ceramics. Two zirconia-reinforced lithium silicate ceramics and one lithium disilicate glass-ceramic were tested. Blocks of all materials were sectioned into tiles …
-
Experimental and theoretical studies of surface and volume changes in dielectrics induced by long-pulse RF CO₂ laser irradiation
… to polymers is strongly dependent on the absorption coefficient at the emission wavelength. These properties are widely known and used to inform experimental practice but the absorption coefficient used in the literature is usually that measured at room temperature and low power. In this …
-
Compressional wave speed and absorption measurements in a saturated kaolinite-water artificial sediment.
The absorption coefficient for compressional waves in a water-saturated kaolinite clay was measured in the frequency range 100 to 150 kHz using a pulse technique with spherically diverging waves. The measurement also permitted determination of the sound speed, V . For one condition of the clay with …
-
Study on single and double layers micro-perforated panel absorbers and optimal design by genetic algorithm
… of micro-perforated panel absorber, the acoustic absorption performance of single and double layers MPP absorbers are investigated. The analytical formula for calculating the absorption coefficient of single and double layers micro-perforated panel are derived by the equivalent circuit method. …
-
EVALUATION OF TERAHERTZ TECHNOLOGY TO DETERMINE CHARACTERISTICS AND CONTAMINANTS IN ENGINE OIL
… by measuring refractive index and absorption coefficient on different conditions. Four experiments were performed to identify the ability of terahertz technology on various engine oil grades, engine oil types, and engine oil contaminants by using terahertz time-domain spectroscopy …
-
Sound absorption characteristic of lightweight brick containing Expanded Polystyrene Beads (EPS) and Palm Oil Fuel Ash (POFA)
… of this research is to identify the sound absorption characteristic of lightweight bricks containing expanded polystyrene beads (EPS) and palm oil fuel ash (POFA). In order to fulfill the standard of a lightweight brick to be used as a building element, the physical and mechanical …
-
Physical and acoustic properties of petroleum and renewable based polyurethane foam filled with shorea leprosula
… of polymer foam composites (PF) towards sound absorption coefficient (SAC) based on the wood fiber size with range of 150-200 μm (powder), 250-300 μm (fibrous) and 900-1000 μm (flakes). 5 wt%, 10 wt%, 15 wt% and 20 wt% of SL filler content and thickness of 10 mm, 20 mm and 30 mm were used for …
-
The effect of Meranti Merah wood fiber loading and sizes to the absorption property of polymer foam composites
… Polymer foam composites (PFC) were developed for absorption material based on epoxy, renewable monomer from waste cooking oil, isocyanates and wood fiber fillers. The polymer foam composite (PFC) were fabricate based on four percentages of wood fiber filler loading which are 5, 10, 15, and 20 wt% …
-
Theory and Experiment of Antimony-Based Type-Ii Superlattice Infrared Photodetectors
… is developed to model the band structures and absorption coefficient. The calculated absorption coefficient spectra agree very well with our experimental curves, validating the effectiveness of the eight-band k · p method. Second, quantum efficiency (QE), an important figure of merit for …
-
Studies on structural, electronic and optical properties of SnO2 doped with nitrogen, chloeine, antimony and indium
… such as the dielectric function, reflectivity, absorption coefficient, and energy-loss spectrum, are in good agreement. According to the predicted absorption coefficient, doped SnO2 has a noticeable band of absorption. Doped SnO2 exhibits superior absorption in the visible area of the …
-
Theoretical Study of the Transverse Dielectric Constant of Superlattices and Their Alloys (Refraction, Absorption)
… of the index of refraction. (eta)((omega)) and absorption coefficient, (alpha)((omega)).
-
Enabling Biomedical Imaging Diagnostics using Optical Methods
… ultrasound resolution, the qualitative optical absorption distribution that reveals optical contrast. The location information of the imaged target is then used as a-priori information for the image reconstruction in diffuse optical tomography. Diffuse optical tomography systems have the ability …
-
ΕΠΑΓΟΜΕΝΗ ΜΕ ΚΡΟΥΣΕΙΣ ΑΠΟΡΡΟΦΗΣΗ ΜΙΚΡΟΚΥΜΑΤΩΝ ΑΠΟ ΤΟ CO2 ΣΤΟΥΣ 2.7, 6.5 ΚΑΙ 14.8 GHZ
… THE MOLECULAR COLLISIONS HAVE A CHARACTERISTIC ABSORPTION SPECTRUM WITH AN ASSOCIATED ABSORPTION COEFFICIENT SEVERAL ORDERS OF MAGNITUDE LESS THAN THE ORDINARY SPECTRA. THE MEASUREMENT OF COLLISION INDUCED ABSORPTION AT LOW MICROWAVE FREQUENCIESALTHOUGH INVOLVES SEVERAL EXPERIMENTAL …
-
Probing the Superconducting Gap of Lead With Ballistic Phonons
… results for temperature dependences of phonon absorption. Instead, we assume that the phonon-imaging experiment creates small regions of raised temperature that contribute non-equilibrium quasiparticles to the system. Accounting for these quasiparticles, we extract consistent values of both the …
-
Wavelength tuneable frequency domain photon migration spectrometer for tissue-like media
… indicated that the spectrometer estimates absorption with an accuracy of 10%. The instrument estimates the absorption and reduced scattering coefficients with a precision of 3% and 6%, respectively. Optical properties of Intralipid were measured from 710-850 nm in the therapeutic window. …
-
Acoustic metamaterials comprised of dead-end pores and black hole effect for low frequency sound absorption in linear and nonlinear regimes
… for the frequency and the peak value of the absorption coefficient at the lowest frequency resonance in the linear regime, depending on the geometrical parameters. This model is complemented by a Transfer Matrix Model (TMM) and Finite Element Model (FEM) for both pancake and profile …
Page 1 of 7