Mass attenuation coefficient

In this work, polymer composites of high density polyethylene reinforced by micro-sized and nanosized cadmium oxide, lead oxide, and a mixture of both with filler weight fraction of 30% were prepared by compression molding technique and characterized by scanning electron microscope. This investigation aims to present a comparative study between cadmium oxide and lead oxide according to their sizes as fillers in high density polyethylene polymeric matrix for gamma-radiation shielding applications. The mass and linear attenuation coefficients of the investigated composites were measured as a function of g-ray energies ranging from 59.53 keV to 1408.01 keV using standard radioactive point sources (241Am, 133Ba, 137Cs, 60Co, and 152Eu). The measurements were made with a narrow beam geometry setup using a well calibrated hyper pure germanium cylindrical detector. The theoretical values of the mass attenuation coefficients were evaluated using the XCOM program database. The experimental r...

Tungsten-containing bismuth borate glass was made by melt quenching and its dosimetry and X/gamma protection properties were evaluated. The glass's formability was assessed using X-ray diffraction (XRD). The Makishima-Mackenzie approach was used to compute the mechanical properties of the prepared glass samples. As the tungsten trioxide (WO 3) concentration increases from 0 to 20 wt %, the prepared glass samples become denser (4.256 g cm-3 to 7.041 g cm-3). The values of Young's modulus (Y), bulk modulus (B), shear modulus (S), and longitudinal modulus (L) rose with increasing WO 3 content from 23.39 to 47.62 GPa, 12.92-37.94 GPa, 9.76-18.45 GPa, and 20.24-51.77 GPa, respectively. Additionally, the glass network's micro-hardness increased from 0.35 to 1.04 GPa while Poisson's ratio (σ) decreased from 0.436 to 0.408 as the content of WO 3 rose. In addition, the refractive index of the prepared glasses increase, while the energy band gap decreases with increasing WO 3 addition. Experimental measurements of γ-ray protection parameters were determined using radioactive sources and a NaI(TL) detector while the dosimetry parameters were simulated using MCNP code. The S5-sample showed the highest dosimetry parameters and X/γ-ray attenuation characteristics. Compared to other radiation shielding materials and newly investigated glasses, the prepared glass samples offer perfect X-ray safety and effective γ-ray shielding, making them suitable for nuclear shielding in various applications industrial, medicinal applications, and storage of nuclear waste.

The study focused on investigating the optical absorption properties of bismuth borate glass samples, including characteristics such as Urbach energy, steepness parameter, optical band gap, and refractive index. Bismuth borate glasses were made using the standard melting procedure, with separate doping of cobalt and copper. The optical absorption of the glass samples, both before and after being exposed to gamma-ray radiation, indicates that the doped transition metal ions exist in an octahedral state and function as modifiers by enhancing the level of disorder in the glass matrix where wavelengths of 297 nm and 390 nm, and another peak at 451 nm were detected for Cu + ions in the glass matrix beside two peaks at 540 nm and 720 nm which are attributed to cupreous ions with octahedral coordination. While wavelengths at 220, 348, and 465 nm were appeared in case of adding cobalt oxide, with the peak at 483 nm indicating an octahedral form of cobalt ions. The investigation of the impact of various gamma-ray dosages on the distinct characteristics of the manufactured glass samples has been examined. The samples exhibit slight variations in absorbance when exposed to varying levels of gammaray irradiation, indicating that these glasses are very suitable for immobilizing low levels of radiation. In addition, calculations were performed for the mean free path, effective atomic number, half-value layer, and radiation protection efficiency. The findings demonstrated that glass incorporating Cu exhibited the most effective shielding outcomes within the photon energy range of 1-10 MeV where the linear attenuation coefficient values increased from 0.319 cm 2 /g for a glass containing CoO to 0.344 cm 2 /g for a glass containing CuO at an energy of 1.333 MeV.

Due to their unique features, perylenediimide derivatives attracted much interest in optical and optoelectronic applications. Along this line, we report herein the optical nonlinearity of a water-soluble perylenediimide derivative, namely, N, N'-di(2-(trimethylammonium iodide)ethylene) perylenediimide (TAIPDI), using a femtosecond (fs) laser pulse at various excitation wavelengths and incident powers. The optical features of lightharvesting TAIPDI in both water and methanol were examined using steady-state absorption and emission and time-resolved emission techniques. The linear and third-order nonlinear optical (NLO) properties of TAIPDI dye have been examined. When changing the solvent from water to methanol, the NLO properties of TAIPDI dye were significantly changed. The TAIPDI dye's nonlinear refractive index (n 2) ascribes self-defocusing, while the nonlinear absorption coefficient (β) shows reverse saturable absorption. The magnitudes of β were on the order of 10-10 and 10-9 cm/W for the 7.2 × 10-6 M solutions of this dye in water and methanol, respectively. The n 2 of the TAIPDI dye in methanol is three times greater than that of the dye in water at the same excitation power, wavelength, and dye concentration. The variations in the nonlinear absorption coefficient and nonlinear refractive index of water and methanol may be due to the strong aggregative behavior of dye molecules in water. The third-order NLO susceptibility of TAIPDI dye in water and methanol was measured on the order of 10-13 esu. The results also show that TAIPDI solutions present a relatively high two-photon absorption cross section (2PACS) at different excitation wavelengths, making them attractive for photonics applications. The dye's optical limiting (OL) effects at different concentrations in solution were studied. The optical results revealed that the TAIPDI dye is a good candidate for optical limiter applications.

Transparent conducting oxide (TCO) materials have unique electrical and optical features. One of many TCOs widely employed in practical optoelectronic devices is indium tin oxide (ITO). Many characterization techniques are used to study materials' nonlinear optical (NLO) properties. The simplest and most accurate technique among these is the Z-scan technique, which is widely used. This article introduces a comprehensive review of the optical nonlinearity of the interaction of a high-intensity laser source with an ITO semiconductor material as a promising material for NLO applications.

In this paper, we present results from the measurements of the optical Kerr nonlinearity of indium tin oxide (ITO) thin films of different thicknesses using the femtosecond (fs) Z-scan technique. ITO thin films were prepared by radio frequency magnetron sputtering on a glass substrate at room temperature. The coated ITO thin films were subsequently characterized by UV-visible absorption spectroscopy, x-ray diffraction, and scanning electron microscopy. Using ∼100 fs pulses at 80 MHz repetition rate, the optical Kerr nonlinearity in ITO with different thicknesses was investigated at different excitation wavelengths and incident pulse energies. The optical Kerr nonlinearity was found to be dependent on excitation wavelength, incident power, and ITO thickness, with a maximum value of ∼9 × 10-12 cm 2 /W at a wavelength of 820 nm, power of 1 W, and 170 nm ITO thickness. These results suggest that Kerr nonlinearity in ITO can be tailored by varying the film thickness, which would be ideal for ultrafast all-optical switching in future optoelectronic devices.

Nonlinear optics has become an essential area of study for understanding and harnessing the complex light-matter interactions that occur in molecules, nanostructures, and advanced materials. This review introduces a summary of the latest advancements, with a particular focus on the nonlinear optical characteristics of noble metal nanoparticles, especially silver nanoparticles (AgNPs). These nanomaterials have gained significant interest due to their typical plasmonic features and size-dependent behavior. Silver nanoparticle colloids demonstrate enhanced light absorption at high intensities, known as reverse saturable absorption, along with a selfdefocusing optical response characterized by a negative nonlinear refractive index. It has been observed that the size of noble metal nanoparticles significantly influences their nonlinear optical properties. The thermal lens phenomenon was addressed utilizing a unique approach that considers the

We have studied the structural, optical, electronic and electrical properties of pure and Mg doped ZnO nanosheets compared to bulk ZnO, using the Density Functional Theory (DFT) within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. The calculated band structure, total and partial densities of states show that the ZnO nanosheet have a large band gap than the other found in the bulk ZnO, which increases with increasing concentration of Mg. The absorption coefficient and optical transmittance show a red-shift after doping ZnO, whereas, the reflectivity and electrical conductivity are reduced. These good optical properties of ZnO nanosheets make it promising in optoelectronic devices, especially in solar cell application.

The paper describes the X-ray attenuation in materials according to their atomic number, using six different materials from low atomic number to higher atomic number, Iron (Fe-26) as low atomic number, silver (Ag-47), tin (Sn-50), platinum (Pt-78), gold (Au-79) and lead (Pb-82) as high atomic number. Using the data were taken from the NIST Standard Reference Database 126. From the J. H. Hubbell and S. M. Seltzer work, a table of contents was used. Whereas The mass attenuation coefficient for the above six elements was taken and compared with each other.

The paper describes the X-ray attenuation in materials according to their atomic number, using six different materials from low atomic number to higher atomic number, Iron (Fe-26) as low atomic number, silver (Ag-47), tin (Sn-50), platinum (Pt-78), gold (Au-79) and lead (Pb-82) as high atomic number. Using the data were taken from the NIST Standard Reference Database 126. From the J. H. Hubbell and S. M. Seltzer work, a table of contents was used. Whereas The mass attenuation coefficient for the above six elements was taken and compared with each other.

The process of melt quenching is utilized in the preparation of the PbO-TeO2-MgO-Na2O-B2O3 glasses. The effect of PbO and B2O3 on the physical, structural, and radiation shielding properties of present glasses have been presented in this study. As the lead concentration rises, both the density and the molecular weight rise, climbing from 3.283 to 3.923 g/cm3 and from 105.638 to 128.675 g, respectively. The utilization of PbO as an alternative to B2O3 contributes to an increase in the overall number of at-oms, which in turn contributes to an increase in the molar volume. The XRD spectra show that the samples are amorphous. The different bending and stretching vibrations of the bonds present in the samples are shown by the FTIR spectra. The mass attenuation coefficient (MAC), linear attenuation coefficients (LAC), half-value layers (HVL), and effective atomic number (Zeff) were calculated using Phy-X software within the energy range 0.284–2.506 MeV. These obtained verdicts advocate th...

The attenuation coefficient b is one of the most common ways to describe how strong the carbon flux is attenuated throughout the water column. Therefore, b is an essential input variable in many carbon flux and climate models. Marsay et al. (2015, ) proposed that the median surface water temperature (0-500 m) may be a predictor of b, but our observations from Arctic waters challenge this hypothesis. We found a highly variable attenuation coefficient (b = 0.43-1.84) in cold Arctic waters (<4.1 °C). Accordingly, we suggest that water temperature is not a globally valid predictor of the attenuation coefficient. We advocate instead that the phytoplankton composition and especially the relative abundance of diatoms can be used to parametrize the carbon flux attenuation in local and global carbon flux models.

We describe a spectroscopic technique called interferometric photothermal spectroscopy ͑IPTS͒ that can measure the absorption coefficient of pulsed laser radiation in nonscattering tissue samples. The technique is suitable for measuring effective absorption coefficients from 10 3 to 10 5 cm Ϫ1 . IPTS is particularly attractive because it requires minimal disturbance of the sample. These features indicate potential use for in vivo measurements of tissue absorption coefficients. To validate the technique, the absorption coefficient of pulsed Q-switched Er:YSGG ͑2.79-m͒ radiation in pure water was measured to be 5200 ͑Ϯ500͒ cm Ϫ1 when IPTS was used, in agreement with other published values. IPTS was also used to measure the absorption coefficient of pulsed ArF excimer laser radiation ͑193 nm͒ in bovine corneal stroma ͑in vitro͒, giving a value of 1.9 ͑Ϯ0.4͒ ϫ 10 4 cm Ϫ1 .

This study presents the complex relationship between film thickness and the properties of P3HT:PCBM thin films, looking at how different thicknesses affected their structural and optical properties. Poly(3, hexylthiophene) (P3HT) and poly(3, hexylthiophene) (PCMB) were blended in a 0.6:1 ratio and deposited using spin coating techniques. The research involve investigating the resulting changes in surface topography, optical properties, and electrical behaviour by systematically adjusting the film thickness through multiple coating repetitions ranging from one to three repetitions. Profilometric analysis revealed a direct relationship between film thickness and surface roughness, highlighting the importance of thickness in interfacial interactions within solar cells. Optical studies revealed fascinating trends in absorbance, transmittance, absorption coefficient, and extinction coefficient, highlighting the films' behaviour at various wavelengths. Surprisingly, regardless of thickness, the optical band gap remained constant, providing valuable insights for optimizing photon energy conversion. Measurements of the Hall effect revealed the effect of thickness on carrier mobility, concentration, conductivity, resistivity, and Hall voltage. Thinner films had higher mobility but lower carrier concentration, revealing a delicate balance critical for optimizing charge transport. The comprehensive analysis of the study sheds light on the complex interplay between film thickness and various properties, providing useful guidance for designing efficient P3HT:PCBM organic solar cells. This study's findings highlight the importance of precise control over film dimensions in improving the performance and efficiency of organic photovoltaic devices. This investigation paves the way for tailored approaches in the fabrication of next-generation organic solar cells, pushing the limits of renewable energy technology.

A method for determining the effective removal cross section (∑ R ) of fast neutrons and mass absorption coefficient (µ R ) for gamma rays at energies 661.6 keV and 1332.5 keV is proposed. It is based on relating the ratio (R) of ∑ R to µ R at 661.6 keV and 1332.5 keV to effective atomic number (Z eff ) for elements, compounds, composite materials and alloys. It is shown that the R-values versus Z eff for the most studied materials lie on two master curves. The method was tested by determining ∑ R and µ R for several materials. There is a good agreement between results obtained from the present developed method and the traditional method. Some deviations from the values obtained from the traditional method are discussed as well.

The present investigation deals with the propagation of waves in a micropolar transversely isotropic half space with an overlying inviscid fluid layer. Effects of fluid loading and anisotropy on the phase velocity, attenuation coefficient, specific loss and relative frequency shift. Finally, a numerical solution was carried out for aluminium epoxy material and the computer simulated results for the phase velocity, attenuation coefficient, specific loss and relative frequency shift are presented graphically. A particular case for the propagation of Rayleigh waves in a micropolar transversely isotropic half-space is deduced and dispersion curves are plotted for the same as functions of the wave number. An amplitude of displacements and microrotation together with the path of surface particles are also calculated for the propagation of Rayleigh waves in the latter case

Many light‐depth profiles based on measurements of photosynthetically available radiation (PAR) in the 0–20‐m zone of Lake Zürich were analyzed with respect to phytoplankton development in the epilimnion and the thermocline. Variations in the average value of the vertical attenuation coefficient with time were closely related to variations in biomass. Inspection of the depth distribution of the natural logarithms of light intensity reveals several straight‐line segments. These correspond to zones with differing phytoplankton densities. During the spring bloom and the late summer phytoplankton maximum the biomass development can be followed in detail by interpreting the light‐depth curves. The results show that the vertical attenuation coefficient Kd(PAR) is influenced considerably by chlorophyll a; nonchlorophyll‐related organic and inorganic suspensoids, however, also seem to be of some importance during periods of low productivity.

Süper iletken kütle MgB2-xSiCx (% 5) kütle soğurma katsayıları (% 5) 14,16 -36,37 keV enerji aralığında ölçülerek hesaplanmış ve etkili atom sayıları tahmin edilmiştir. Belirlenen enerjileri, 241-Am'in gama ışını fotonları ile ışınlanmış sekonder hedefler kullanılarak elde edildi. X ışınları 5.9 keV'de 150 eV çözünürlüğe sahip Canberra Ultra-LEGe dedektörü kullanılarak sayıldı. Sonuçlar teorik olarak hesaplanan değerlerle karşılaştırıldı ve ortalama bir deneysel hata ile uyumlu olduğu tespit edildi.

Anomalous absorption and the corresponding change in the optical band gap of a CO2-laser-ablated Si-rich SiO2 (SiOx) film are studied. The optical band gap energy of as-grown nonstoichiometric SiOx is slightly reduced by increasing Si–Si bonds as compared to quartz. After rapid thermal annealing using a CO2 laser, the dehydrogenation of SiOx film further increases the Si–Si bonding states and redshifts the optical band gap by 1eV. Laser ablation is initiated at a laser intensity of &gt;7.5kW∕cm2, leaving numerous luminescent centers that are related to neutral oxygen vacancy defects, increasing the absorption coefficient and related optical band gap energy, and reducing the refractive index in partially annealed SiOx.

The open-cell photoacoustic signal measured in the transmission configuration for aluminum thin plates with thicknesses of 280 μm, 197 μm, and 112 μm is experimentally and theoretically analyzed, in the 20 Hz–7 kHz modulation frequency range. It is shown that the observed differences between the predictions of the standard thermoelastic model and the experiment data of both the amplitude and phase of the photoacoustic signal can be overcome by considering the aluminum samples coated with a thin layer of black paint as volume-absorber materials. This new approach provides a quite good agreement with the obtained experimental data, in the whole frequency range, and yields an effective absorption coefficient of (16 ± 2) mm−1, for a 280 μm-thick sample. The introduction of the finite absorption coefficient led to the correct ratio between the thermal diffusion and thermoelastic components of the photoacoustic signal. Furthermore, it is found that the “volume-absorber” approach accuratel...

Understanding differences between laboratories in the measurement of absorption coefficients of phytoplankton, detrital and coloured dissolved organic material is important if we are to accurately validate MERIS data. Phytoplankton absorption coefficients (a phyto ) and the absorption coefficient of coloured dissolved organic material (a ys ) were determined by three laboratories on natural seawater samples taken from three stations off Plymouth Sound between 50 20.02 °N, 4 10.02 °W, during a second inter-comparison exercise (PlymCal 2). The absorption coefficient of an artificial CDOM sample composed of a coloured humic acid salt suspended in buffered MilliQ water was also determined by the three laboratories. For the natural seawater samples, good agreement was found between a phyto at 442 nm at three stations where a phyto varied between 0.066 and 0.145 m -1 . Over MERIS bands (412 to 680 nm) there was a 14 % difference between laboratories and the standard deviation was small (mean of all labs at MERIS bands ∼0.003 m -1 ). The range in coloured dissolved organic material absorption coefficient at 442 nm was from 0.1 at Station L4 (50 15 °N, 04 12.5 °W) when there was a 6 % difference between laboratories to 1.0 m -1 at Barnpool (50 21.3 °N, 04 10.1 °W), where there was a 48 % difference between laboratories. For the artificial CDOM sample the difference was 13 % at 442 nm and 20 % over MERIS bands. Using a phyto and a ys values at Station L4 for the three laboratories during PlymCal 2, above water surface reflectance and water leaving radiances were calculated and then SeaWiFS OC4 switching band ratios was applied to calculate corresponding SeaWiFS Chlorophyll a (Chla) concentrations. The results showed that the variation in a ys at L4 produced on average an 11 % variation in Chla and that the variation in a phyto resulted in an 18 % variation in Chla. The variation in Chla using in situ absorption coefficients at L4 was less than the accuracy of SeaWiFS Chla using the OC4 algorithm (∼35 %), which suggests that once methodologies have been fixed, the between laboratory variation in a phyto and a ys at L4 is acceptable and will not significantly affect the validation of MERIS data.

The choice of the material base to which the material decomposition is performed in dual-energy computed tomography may affect the quality of reconstructed images. The aim of this work is to investigate how the commonly used bases (water, bone), (water, iodine) and (photoelectric effect, Compton scattering) affect the reconstructed linear attenuation coefficient in the case of the Alvarez–Macovski method. The performance of this method is also compared with the performance of the Dual-energy Iterative Reconstruction Algorithm (DIRA). In both cases, the study is performed using simulations. The results show that the Alvarez–Macovski method produced artefacts when iodine was present in the phantom together with human tissues since this method can only work with one doublet. It was shown that these artefacts could be avoided with DIRA using the (water, bone) doublet for tissues and the (water, iodine) doublet for the iodine solution.

Image artifacts from variable self-attenuation are recognized as major sources of diagnostic uncertainty in SPECT. For myocardial perfusion studies, an attenuation map is often obtained from a separate transmission study. However, for many applications such as bone SPECT, it has been believed to be unnecessary to obtain a transmission study to correct for the effects of attenuation. We have had significant success in clinical management of lower spine pain using bone SPECT. This success has led us to consider SPECT for the management of cervical spine pain. Cervical spine reconstructions without attenuation correction are difficult to interpret, because the high attenuation in the mandible and skull tends to decrease estimates of activity of the upper cervical spine, and the lower cervical/upper thoracic vertebrae are obscured by the shoulders. We present a technique that uses downscatter to provide attenuation correction for these acquisitions and compare it with other recognized a...

Despite the importance of the optical properties such as the downwelling diffuse attenuation coefficient for characterizing the upper water column, until recently no in situ optical measurements were published for the Red Sea. Kirby et al. 1 used observations from the Coastal Zone Color Scanner to characterize the spatial and temporal variability of the diffuse attenuation coefficient (K d ( )) in the Red Sea. To better understand optical variability and its utility in the Red Sea, it is imperative to comprehend the diffuse attenuation coefficient and its relationship with in situ properties. Two apparent optical properties, spectral remote sensing reflectance (R rs ) and the downwelling diffuse attenuation coefficient (K d ), are calculated from vertical profile measurements of downwelling irradiance (E d ) and upwelling radiance (L u ). K d characterizes light penetration into water column that is important for understanding both the physical and biogeochemical environment, including water quality and the health of ocean environment. Our study tests the performance of the existing K d (490) algorithms in the Red Sea and compares them against direct in situ measurements within various subdivisions of the Red Sea. Most standard algorithms either overestimated or underestimated with the measured in situ values of K d . Consequently, these algorithms provided poor retrieval of K d (490) for the Red Sea. Random errors were high for all algorithms and the correlation coefficients (r 2 ) with in situ measurements were quite low. Hence, these algorithms may not be suitable for the Red Sea. Overall, statistical analyses of the various algorithms indicated that the existing algorithms are inadequate for the Red Sea. The present study suggests that reparameterizing existing algorithms or developing new regional algorithms is required to improve retrieval of K d (490) for the Red Sea.

A polycrystalline CdSe thin films doped with (5wt%) of Cu was fabricated using vacuum evaporation technique in the substrate temperature range(Ts=RT-250)oC on glass substrates of the thickness(0.8?m). The structure of these films are determined by X-ray diffraction (XRD). The X-ray diffraction studies shows that the structure is polycrystalline with hexagonal structure, and there are strong peaks at the direction (200) at (Ts=RT-150) oC, while at higher substrate temperature(Ts=150-250) oC the structure is single crystal. The optical properties as a function of Ts were studied. The absorption, transmission, and reflection has been studied, The optical energy gap (Eg)increases with increase of substrate temperature from (1.65-1.84)eV due to improvement in the structure. The amorphousity of the films decreases with increasing Ts. The films have direct energy gap and the absorption edge was shift slightly towards smaller wavelength for CdSe:Cu thin film with increase of substrate tempe...

Effect of media temperature on the acousto-optic (AO) phase matching condition is examined both theoretically and experimentally by an example of tellurium dioxide crystal with 10.5° cut-angle. It is shown that variation of the AO crystal temperature changes the acoustic wave velocity that is involved into the AO interaction and shifts the AO diffraction phase matching frequency. We introduced the temperature coefficient of AO phase matching frequency shift. The measurements of frequency shift magnitude were carried out at the optical wavelengths from 0.44 µm to 1.52 µm. It is shown that the shift coefficient decreases with the optical wavelength. A method is proposed that makes it possible to calculate the temperature shift coefficients for AO devices in a wide range of optical wavelengths. The coefficients obtained by the proposed method are in good agreement with the experimental data. Ultrasound attenuation is also examined experimentally in the given AO cell in a wide range of acoustic wave frequencies.

A great deal of research has been performed on refractive index n and extinction coefficient k due to varieties of applications in optical industries. The dispersion equation is described for the photons of varying energies and their interactions with materials since there is a strong correlation of n and k with wavelength. Measurements based on reflectance can be expensive and are very difficult due to compositional variations. We present a low-cost reflectance probe fiber optics designed in-house to determine the absorption coefficients and refractive index of solids. The solutions using a modified Beer-Lamberts Law and merging the concentration and extinction coefficient terms into an absorption coefficient, α, can be given by the equation I = I 0 exp (-α* d) where I is the transmitted intensity, I 0 is incident intensity and d is the thickness. We have experimented with several semiconductor compounds for this study.

 Eight soil samples were selected around Najaf governorate at depth levels 40-50 cm. X-Ray Fluorescence (XRF) was used to determine the concentrations of major and trace elements. Liner and mass attenuation coefficient (µ, µρ) have been determined at gamma energies (662, 1172,1332) keV using NaI (Tl) detector. The range of linear attenuation coefficients for calculated samples were (0.553-1.163) cm-1, (0.122-0.178) cm-1 and (0.049-0.105) cm-1 at (662, 1172,1332) keV respectively. The range of mass attenuation coefficients obtained (0.39-0.76) cm2/gm, (0.087-0.117) cm2/gm and (0.0336-0.074) cm2/gm at (662, 1172,1332) keV respectively. The results showed that Fe content in the samples has a strong effect on the mass attenuation coefficient and this parameter is inversely proportional to the gamma energy.

The high ultrasound frequencies namely 2 MHzand 10MHz frequencies were selected for disruption of cell density of A.niger based on Rayleigh-plesset's bubble activation theory. The A.niger suspensions of 10 ml each inoculated to cell density of 10 7 per ml were exposed to ultrasound of out power of 60 watts/ml for times of 1 min step up to 10 min. A sonotrode of 12mm diameter was used throughout the study. The sonication vessel kept inside the water bath which was maintained at constant temperature of 300 K by using automatic temperature control bath.

We report picosecond acoustic measurements of longitudinal sound dispersion and attenuation in an amorphous SiO 2 layer at temperatures from 20 to 300 K over frequencies ranging from about 40 to 200 GHz. The sample is a radio frequency cathodic sputtered silica layer grown on a sapphire substrate with an aluminum film transducer deposited on top. Acoustic attenuation is evaluated from the simultaneous analysis of three successive echoes using transfer matrix calculation. Results are found to follow rather well a model combining coupling to thermally activated relaxations of structural defects and interactions with thermal vibrations. This leads to a nontrivial variation of the attenuation coefficient with frequency and temperature. The number density of relaxing defects in the SiO 2 layer is found to be slightly higher than that in bulk v-SiO 2 . In contrast, similar anharmonic contribution to acoustic absorption is observed in both systems. The velocity variations are also measured and are compared to the dynamical velocity changes deduced from the sound attenuation.

Análisis experimental de las propiedades ópticas no lineales de los derivados del 1-aril-3-(4metoxifenil)-5-(Benzo(d)(1,3)Dioxol-5-yl)-2Hpirazolinas. Experimental analysis of the nonlinear optical properties of 1-aryl-3-(4methoxyphenyl)-5-(Benzo(d)(1,3)Dioxol-5-yl)-2H-pyrazolines derivatives.

The Alqueva reservoir (South of Portugal) in the Guadiana river basin constitutes the most important water resource in southern Portugal for domestic and agricultural consumption. We present a methodology developed to characterize spatial and temporal variations of Secchi depth and diffuse attenuation coefficient (both related to dissolved/suspended particles and to water transparency), using high spatial resolution satellite images from Sentinel-2 Multi-Spectral Instrument (MSI). Empirical relations between satellite retrievals of surface reflectances and in situ measurements of water parameters were defined and applied to the entire reservoir for spatial and temporal analysis in the period July 2017–June 2019, useful in the identification of microalgae blooms and rapid variations in water characteristics, which allowed us to differentiate five zones. Water estimates with lower transparency and higher attenuation of radiation were found in the northern area of Alqueva reservoir dur...

Normal incidence sound absorption coefficient of materials is usually calculated with the use of an impedance tube following the ISO 10534-2 international standard. The same is applied in the evaluation of the sound absorption characteristics of pavement mixtures. In this research an impedance tube which was specifically designed to be used in field conditions has been developed. In order test the tube six asphalt slabs were constructed in laboratory and its sound absorption coefficient measured with the new impedance tube. Then, several road sections, with different types of surface, among dense asphalt layers and thin layers, namely with rubberized asphalt were tested. In this paper, some considerations are made regarding the performance of the new impedance tube and the sound absorption coefficient of each asphalt mixtures.

The need to understand and monitor climate change has led to proposed radiometric accuracy requirements for space-based remote sensing instruments that are very stringent and currently outside the capabilities of many Earth orbiting instruments. A major problem is quantifying changes in sensor performance that occur from launch and during the mission. To address this problem on-orbit calibrators and monitors have been developed, but they too can suffer changes from launch and the harsh space environment. One solution is to use the Moon as a calibration reference source. Already the Moon has been used to remove post-launch drift and to cross-calibrate different instruments, but further work is needed to develop a new model with low absolute uncertainties capable of climate-quality absolute calibration of Earth observing instruments on orbit. To this end, we are proposing an Earth-based instrument suite to measure the absolute lunar spectral irradiance to an uncertainty 1 of 0.5 % (k=1) over the spectral range from 320 nm to 2500 nm with a spectral resolution of approximately 0.3 %. Absolute measurements of lunar radiance will also be acquired to facilitate calibration of high spatial resolution sensors. The instruments will be deployed at high elevation astronomical observatories and flown on high-altitude balloons in order to mitigate the effects of the Earth's atmosphere on the lunar observations. Periodic calibrations using instrumentation and techniques available from NIST will ensure traceability to the International System of Units (SI) and low absolute radiometric uncertainties.

Abstract- Crystallites of ZnO and Zn0.99Co0.01O have been grown on glass substrate by wet chemical decomposition of zinc/cobalt-amino complexes in aqueous medium. Structural properties of grown crystallites were investigated by the help of X-ray Diffractometer, Scanning Electron Microscope and Energy Dispersive X-ray spectroscope. Keywords- Doped ZnO; Different morphologies

Q -switched Nd:YAG laser ablation of a turbid medium (paint) is studied. The optical properties (absorption coefficient, scattering coefficient, and its anisotropy) of a paint are determined with a multiple scattering model (three-flux model), and from measurements of reflection-transmission of light through thin layers. The energy deposition profiles are calculated at wavelengths of 532nm and 1.064μm. They are different from those described by a Lambert-Beer law. In particular, the energy deposition of the laser beam is not maximum on the surface but at some depth inside the medium. The ablated rate was measured for the two wavelengths and compared with the energy deposition profile predicted by the model. This allows us to understand the evolution of the ablated depth with the wavelength: the more the scattering coefficient is higher, the more the ablated depth and the threshold fluence of ablation decrease.

A theoretical study of the electronic properties of the ground state and excited states and the linear and the third-order nonlinear optical properties (i. e., absorption coefficients and refractive indices) in a spherical GaAs pseudodot system is reported. The variational procedure has been employed in determining sublevel energy eigenvalues and their wave functions within the effective mass approximation. Our results indicate that the chemical potential of the electron gas and the minimum value of the pseudoharmonic potential have a great influence on the electrical and optical properties of hydrogenic impurity states. Also, we have found that the magnitudes of the absorption coefficient and the refractive index change of the spherical quantum dot increase for transitions between higher levels.

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This research, study the effect of the thickness on titanium dioxide (TiO2) , that prepared by the Sol-Gel Process method on the optical properties of (TiO2) thin film with different thickness (54, 64 and 89 nm), the thickness effect on optical properties (energy gap , absorbance spectrum, transmittance spectrum, reflectance, refractive index, extinction coefficient, absorption coefficient, real and imaginary dielectric constant) ,this study shows that thickness have an effect on all these parameters .  

We have shown that solutions to the radiative transfer equation for a homogeneous slab yield a zenith radiance reflectance that for collimated beam incidence in the nadir direction can be expressed in terms of the lidar ratio, defined as the extinction coefficient divided by the 180$$^\circ $$ ∘ backscattering coefficient. The recently developed QlblC method, which allows one to quantify layer-by-layer contributions to radiances emerging from a slab illuminated with a collimated beam of radiation, was used to show explicitly that in the single-scattering approximation the attenuated backscatter coefficient estimated by the new QlblC method gives the same result as the lidar equation. Originally developed for the continuous wave (CW) lidar problem, we have extended the new QlblC method to apply to the pulsed lidar problem. A specific example is provided to illustrate the challenge encountered for ocean property retrievals from space observations due to the fact that a very significan...

One of the most important challenges in the world is climate change causing the warming of oceans and its direct and indirect impacts on ecosystems. This fact makes it important to have and utilize regular data sets to increase understanding. This study, it is aimed to understand the descriptive properties of outer Izmir Bay by using alternative data sets from satellite technology. Remotely sensed data sets of the sea surface temperature, chlorophyll-a, and attenuation coefficient through satellite technology were analyzed over a long time period, between 01/2004 and 12/2021. Results showed stable properties of these variables and a significantly weak increasing trend in chlorophyll-a and attenuation coefficient. Even though no significant trends were detected in sea surface temperature, months from winter to summer showed a significant increasing trend for the temperature. Seasonal warming trends can be the cause of the successful settlement of warm-water species in Izmir Bay, as it is maybe the case in other parts of the Mediterranean Sea.

The objective of this study is to investigate the mass attenuation coefficients (μm) of lanthanumhexaborides and ceriumhexaborides over a wide photon energy range emitted from the main radioactive sources used in medicine and industry. 125 I, 99m Tc, 131 I, 137 Cs, 60 Co and 152 Eu gamma ray sources were used in the experiments. The materials synthesized in powder form were first pelletized and then irradiated by photon beams. At the end, it was seen that there is successful consistency between the obtained experimental data and the previous theoretical results. It was also observed that the investigated samples are comparable enough to the known standard gamma shielding materials, especially to lead which is one of the most common one. In conclusion, it is understood that the presently investigated samples have a promising aspect in terms of developing new shielding materials against gamma rays.

A critical parameter to assess the environmental status of water bodies is the transparency of the water, as it is strongly affected by different water quality related components (such as the presence of phytoplankton, organic matter and sediment concentrations). One parameter to assess the water transparency is the diffuse attenuation coefficient. However, the number of subsurface irradiance measurements obtained with conventional instrumentation is relatively low, due to instrument costs and the logistic requirements to provide regular and autonomous observations. In recent years, the citizen science concept has increased the number of environmental observations, both in time and space. The recent technological advances in embedded systems and sensors also enable volunteers (citizens) to create their own devices (known as Do-It-Yourself or DIY technologies). In this paper, a DIY instrument to measure irradiance at different depths and automatically calculate the diffuse attenuatio...

The design and slicing technique of artificial soft tissue are presented. Artificial soft tissue has optical penetration properties similar to biological tissues. The soft tissues are made of agar dissolved in water as a transparent tissue (control) incorporated with scatter materials such as polystyrene microspheres and absorbers such as artificial dairy substitute, coffee mate (Carnation Co.). The radiation&#39;s interaction with 20 and 40 keV X-ray, and visible light (400–800 nm) with different types of tissue phantoms has been investigated. The half value layer (HVL), attenuation coefficient, energy density and penetration depth through the artificial tissues has been calculated. X-ray radiation depth show significant reduction in soft tissue incorporated with polystyrene microspheres. At extremely low energy (E), the half value layer decreases with increasing the energy, while the attenuation coefficient increase. The calculated values of the half value layers are in very good ...

A primary aim of SOFAR propagation experiments conducted recently has been to obtain measurements of the acoustic attenuation coefficient in the ocean. However, the interpretation of the data gained in these experiments has been the subject of considerable debate. In particular, the relative importance of the scattering loss contribution to the total observed attenuation at low frequencies is an unresolved problem: Apart from relatively localized regions of deep scattering associated with water-mass movement, the distribution of scatterers (which may be either physical objects such as marine life and air bubbles or small changes in oceanographic parameters due to turbulence) is assumed to be concentrated in the region near the ocean surface. A propagation model which includes such a stratified scattering loss has been developed. The theoretical attenuation coefficient is found to be dependent on the velocity profile shape. This may account for regional variations in the observed att...

To study the doses received by patient submitted to ionizing radiation, several materials are used to simulate the human tissue and organs. The total mass attenuation coefficient is a reasonable way for evaluating the usage in dosimetry of these materials. The total mass attenuation coefficient is determined by photon energy and constituent elements of the material. Currently, the human phantoms are composed by a unique material that presents characteristics similar to the mean proprieties of the different tissues within the region. Therefore, the phantoms are usually homogeneous and filled with a material similar to soft tissue. We studied ten materials used as soft tissue-simulating. These materials were named: bolus, nylon ® , orange articulation wax, red articulation wax, PMMA, modelling clay, bee wax, paraffin 1, paraffin 2 and pitch. The objective of this study was to verify the best material to simulate the human cerebral tissue. We determined the elementary composition, mass density and, therefore, calculated the total mass attenuation coefficient of each material. The results were compared to the values established by the International Commission on Radiation Units and Measurements -ICRU, report n° 44, and by the International Commission on Radiation Protection -ICRP, report n° 89, to determine the best material for this energy interval. These results indicate that new head phantoms can be constructed with nylon ® .

In self-reinforced polymeric materials (SRPMs), the same polymer forms both the reinforcing and matrix phases. SRPMs are also referred to as single-phase or homocomposites. Moreover, in the open literature, such polymer composites in which the reinforcement and matrix polymers are different but belong to the same family of polymers are also termed as SRPMs. The basic concept of selfreinforcement is the creation of a one-, twoor three-dimensional alignment (1D, 2D or 3D, respectively) within the matrix to fulfill the role of matrix reinforcement. Reinforcing action requires that the generated structure possesses a higher stiffness and strength than the matrix and, in addition, is well “bonded” to the matrix polymer. As a consequence, the stress can be transferred from the “weak” matrix to the “strong” reinforcing structure, according to the “working principle” of all composites. [1] Current trends toward environmentally friendly composite systems focus on the use of natural fibers as...