Glass Cylinder Research Articles

Fragmentation of brittle material by shock wave lithotripsy. Momentum transfer and inertia: a novel view on fragmentation mechanisms

Shock wave lithotripsy is the only non-invasive stone therapy and in clinical use since 1980. In spite of decades with millions of patients treated, the mechanism of fragmentation is still under debate. Detailed knowledge of the fragmentation process is required for improvements regarding safety and efficiency. The purpose of this paper is to gain a deeper insight into the mechanism of fragmentation by drawing attention to basic physical laws of inertia and momentum transfer. Many fragmentation experiments are based on the overall efficiency of multiple shock waves in crushing kidney stones or artificial model stones utilizing small baskets or latex pouches. Due to the high dynamic nature of the fragmentation process, in vitro and in vivo, a detailed action of a single shock wave on a particular stone target is difficult to investigate. We utilized a bifilar stone suspension, which allowed us to observe horizontal movements of model stones, their return to the initial position and orientation for repeated exposure of separate identical shocks. The method does not describe the entire fragmentation process in detail but elucidates a mechanism, which may be effective throughout shock wave lithotripsy in general. Measurements on model stones in water revealed forces in the range of 370 N, acceleration values of 100,000–200,000 m/s2 (≈ 10,000 g) and gained momentum of 3.7 × 10− 4 kg m/s we consider sufficient to break most human urinary stones. Fracture patterns of repeated identical shock waves show typical features supporting spallation (Hopkinson effect) and the mechanism of momentum transfer. Schlieren and photo-elastic images provide a visual impression of spatial stress in a transparent acrylic glass cylinder, cavitation fields outside and at the surface of the cylinder, which are compatible with the inertia model. The proposed mechanism covers coarse as well as fine fragmentation. Collapsing cavitation bubbles may have an impact on the fragmentation process but although expected, a direct action of micro-jets on sample surfaces could not be detected.

Photocatalytic inactivation of microalgae: efficacy and cell damage evaluation by growth curves modeling

Ballast water in ocean transportation is an important vector for species transferring between areas not connected naturally. Ultraviolet irradiation is a common treatment to inactivate organisms in ballast water. A primary disadvantage inherent to ultraviolet treatment is photoreactivation. This study evaluates the possibility to enhance the efficacy of ultraviolet disinfection with the addition of TiO2 photocatalysis by using the microalga Tisochrysis lutea as an indicator organism. The culture was treated with different ultraviolet doses using a tubular flow-through UV-C reactor equipped with a glass cylinder coated with fixed TiO2. To study the influence of the photoreactivation, an aliquot from every sample was exposed to light immediately after the treatment and another aliquot was kept in the dark for 5 days and subsequently exposed to light. The growth curves were modeled and disinfection kinetics parameters were consequently obtained in order to compare the photocatalytic and ultraviolet disinfection. Results indicated an increase in the disinfection rate by a factor of 4.18 using the photocatalytic reactor, in comparison with the UV-only treatment, in samples exposed to light immediately after the treatment. On the other hand, the disinfection rate was increased, but not significantly, in samples stored in dark after irradiation using the photocatalytic reactor. Data also showed the high extent of photoreactivation, which was reduced by the photocatalytic treatment.

Strong angular dependence of resonant states in 2D dielectric cylinder rings

We investigate collective resonators made of dielectric cylinders assembled as two-dimensional regular octagons and decagons. These structures exhibit collective resonance states that change their intensity with the incident radiation angle. While most parts of the spectra present small or even null variation, one of these resonances presents high-sensitivity to the incidence angle. This strong variation is well characterized in terms of the electric field intensity distribution of a resonant state where all the cylinders show the lowest order Mie resonance and the neighbors alternate their polarities. The collective state is optimally excited when radiation impinges on a vertex of the polygonal arrangement of cylinders, while the response decreases to its minimum when the incident field hits an edge (two cylinders at the same time). The resonant state and its high dependence on the excitation incidence angle have been found in both octagonal and decagonal configurations for different dielectric permittivity values. In addition, the scalability of Maxwell equations warranties the same behavior if the whole system is downscaled to terahertz or optic frequencies. The study was performed by finite integration time domain calculations of scattering and transmission for different incidence angles. Experimental measures in the microwave range were taken from photonic molecule prototypes made of centimeter-scale glass cylinders (ɛ = 4.5). We find an overall excellent agreement between measurements and simulations. We propose that photonic molecules made of polygonal rings of dielectric cylinders are an ideal structure to build angle sensors using the strongly varying state that they present.

Field of Rods: Part 2. Mockup and Performance Testing of TSSA

ABSTRACTEric Owen Moss Architects has designed a glass cylinder roof for the 8511 Warner Drive project in Culver City, CA. Curved laminated glass tubes suspended from a structural frame provide a striking structure unequalled in structural glass design. Their pursuit of discovering methods that bring projects to public prominence is evident in this design of hanging tubes. The engineering design and redundancy was presented at Engineered Transparency 2016 and this is a continuation of the mockup and validation. The project uses nearly 200 curved annealed laminated tubes (of various lengths) suspended from a structure where mechanical fastening of the glass tube by drilled holes and bolts is architecturally unappealing. The top of the tube is designed with conventional structural silicone and a “Yoke” inside the middle of the tube is attached with TSSA. The Yoke is bonded to curved steel 65 mm × 125 mm rectangular patches with TSSA. The curved fittings attached to the glass have to be machined to match the glass that has a 305 mm radius. The engineering challenge is to use the TSSA to resist the rotational stresses between the two halves of the cylinder during wind and seismic events. Mockup challenges with glass fracture due to heat capacity of large metal fittings were resolved with engineered steel fittings that were smaller in mass and dimensionally adjusted. Additional challenges include dimensional tolerances in glass and machined fittings that resulted in trapped air in the adhesive. The aesthetic trapped air issues were overcome by layering TSSA films upon each other to resolve the tolerances. A customized quality assurance process was implemented to validate performance of the cured adhesive. Results of quality assurance tests are presented. The design team is in the process of executing the design through mockup and validation for full scale production.

Pressure Wave Elimination in Iraqi Crude Oil Pipelines Using Novel Porous Filter and Electronic Control System

The pressure wave is a serious problem in crude oil transportation pipelines. It is generated at the beginning and at the end of crude oil pumping process or as a result of sudden closing of valves. The high turbulence fluid particles in presence of pressure wave resulting in sever stresses on pipe walls needing for maintenance and replacement after a period of time. It is also leading to dissipation of flow energy consuming much more power for oil pumping. The objective of the present work is to decrease and eliminate the pressure wave in Iraqi crude oil pipelines through designing, manufacturing, and testing of a novel pressure wave filter with optimum design. The experimental system consists from: porous filter, oil pipe, pump, AC drive, and digital pressure transducers. The porous filter that was tested to eliminate the pressure wave is composed from various pipes (0.5 inch Perspex pipe, 1 inch PVC pipe, and 2 inches stainless steel pipe) with different porous materials to absorb the pressure energy from the fluid particles. These porous media are (1.5cm, 1cm, 0.4cm glass beads, and glass cylinders of 2cm length, 2cm outer diameter, and 2mm thickness). The experimental results proved the successful of the invented porous filter for eliminating the pressure wave by 99% using optimum design without suppressing the flow rate of crude oil in the pipe. The results obtained are quite significant since it awards a simple and low-cost solution for a real and practical problem in crude oil transportation sector.

A Robust Two-axis Tilt Angle Sensor Based on Air/Liquid Two-phase Dielectric Capacitive Sensing Structure

ABSTRACT This paper presents the design, fabrication, and characterization of a two-axis tilt angle sensor based on the air/liquid two-phase dielectric capacitive sensing structure. The sensor consists of five electrodes, one serves as the exciting electrode and two pairs of electrodes as sensing ones, which are arranged at identical positions surrounding a glass cylinder tube. The glass cylinder tube is partly filled with dielectric liquid to form the air/liquid two-phase dielectric medium. Based on this arrangement, the proposed sensor can detect roll and pitch angles, simultaneously. A computational simulation and experimental measurements are performed to study the performance of the sensor. The numerical simulation is carried out with a finite element analysis using COMSOL. A prototype of the sensor was fabricated, and its performance was evaluated. The tilt angle sensor was employed on a printed circuit board with a conditioning circuit, consisting of a sine wave generator, pre-amplifiers, rectifiers, and low pass filters. The experiment results confirmed that the roll angle detection has a linear range in the range of −60° to +60° with non-linearity error of 6.6%. The sensitivity and resolution in this range are 18.2 mV/° and 0.55°, respectively. For pitch angle detection, the linear range is −16° to +16° with non-linearity of 10%, and sensitivity and resolution of 58.2 mV/° and 0.17°, respectively.

Ballistic fragmentation confinement of coated brittle transformer bushing models

Pressurized borosilicate glass cylinders were used to (1) simulate experimentally high-voltage transformer bushing behavior under high-velocity impact from an air gun, (2) investigate fragment dynamics to estimate the impact range of airborne fragments, and (3) evaluate the efficiency of an elastomeric coating on ballistic damage initiation and fragment confinement. Using high-speed cameras, the velocities and directions of ejected fragments from the cylinders were determined along with fragment distribution symmetry. Drop tower testing was added to independently verify the air gun results on the cylinders through a different test under similar impact energies using flat samples of the same glass. Elastomeric coatings were also applied to both the cylinders and flat samples to increase their resistance to high energy impact. It has been shown that internal pressure in the glass cylinders plays a major role in the failure modes during high-velocity impacts. This pressure affects velocities, directions, and symmetry of fragment distribution. The fragment impact range investigation turned out to be inconclusive due to highly erratic behavior of the fragments after the blast. Most importantly, it has been ascertained that fragment dynamics are drastically altered by elastomeric coatings, producing a high level of fragment confinement both in the drop tower and gun tests. By extrapolating the air gun and drop tower data out to high power rifle energy levels, unique predictions of the critical coating thicknesses to prevent the initiation of ballistic damage and to confine fragments in borosilicate glass cylinders and C-120 porcelain bushings were achieved for the first time.

Antimicrobial activity of phytoextracts on opportunistic oral bacteria, yeast and bacteria from probiotics

Developed experimental assays enable us to compare the antimicrobial activity of herbal medicinal drugs on Lactobacillus and Bacillus strains probiotics, which have been claimed to possess the ability of suppressing the growth of various oral pathogens. In the treatment of periodontal disease it is advisable to use a comprehensive approach which would include the application of herbal remedies and probiotics. The combination of such effects may be a new approach in dentistry due to their complementary antimicrobial activity. In this study, we researched antimicrobial effects of herbal medicinal drugs (tinctures of some medical plants, solutions Rotocanum and Chlorophyllipt) against collection strains and clinical strains isolated from the oral cavity of patients with periodontitis, and probiotic strains Bacillus subtilis UKM В-5007 and Bacillus licheniformis UKM В-5514 that are part of the active base of probiotic Biosporin (Ukraine), Bacillus clausii from the probiotic Normaflore (Hungary), as well as the strains Lactobacillus spp. – from probiotic Lactobacterinum (Biopharma, Ukraine). For investigation, the standard agar dilution method was used in modification with glass cylinders. The results of the research showed that among the studied herbal medicinal remedies, tinctures of Eucalypthus viminalis, Mentha piperita and Chlorophyllipt had the strongest antimicrobial activity. Probiotic strains are also sensitive to herbal tinctures (except the tinctura of wormwood), which indicate the possibility of only consecutive usage (with an interval of time) of herbal remedies and probiotics in combination therapy in the treatment of periodontal diseases.

Threshold angle and valid fracture of the sectored flexural specimen

AbstractThe sectored flexural specimen was developed over a decade ago to measure the strength of ceramic and glass tubes and cylinders in which flaws on a tube's or cylinder's outer surface are limiters of axial tensile failure stress. Using the specimen's geometry, the associated axial tensile failure stress can be analytically calculated from the failure force measured from simple uniaxial bending, and multiple specimens (and test data) can be harvested from a single tube or cylinder. The sector angles of specimens in previous studies were somewhat arbitrarily chosen and usually produced validly occurring fractures and data; however, if the angle used was too small (relative to the tube's or cylinder's geometry), then undesirable application‐irrelevant edge‐located failures resulted. To avoid such failures in specimen design, a threshold sector angle was identified to guide the selection of a minimum sector angle (and consequential cross section) for any arbitrary sector flexural specimen harvested from a tube or cylinder. If the sector angle of the specimen is larger than the threshold value, then fracture will not occur at a specimen's edge and the measured axial failure stress will be limited by surface‐located flaws on the tube's or cylinder's outer surface.

Destruction of Aqueous Phase Organic Pollutants Using Ultraviolet Light-Emitting Diodes and Photocatalysis

The photocatalytic degradation of dyes (Allura Red AC and Brilliant Blue FCF) in water using ultraviolet light-emitting diodes (UV-LED) and an immobilized titanium dioxide (TiO2) as a photocatalyst was investigated using a novel bench-top Teflon® reactor. This reactor has been uniquely designed to contain low-powered UV-LEDs combined with TiO2 immobilized substrates. A sol-gel method was used to anneal TiO2 to three different substrates: standard microscope quartz slides, quartz cylinders, and borosilicate beads. Scanning electron microscopy (SEM), Raman spectroscopy, and mass comparisons techniques were performed for TiO2 characterization. High-resolution images confirmed the presence and morphology of TiO2 on the substrates. These analyses demonstrated the TiO2 coating was uniform and predominantly had the anatase crystalline phase structure. The slide had the largest individual TiO2 surface area of 0.187 mg cm−2. Results indicated the size, shape, packing, and stirring properties were factors that determine overall photocatalytic properties and degradation inside the reactor. The adjusted rate constants for an ideal completely mixed batch reactor (CMBR) were 1.69 * 10−3, 5.39 * 10−3, and 4.46 * 10−3 min−1 for the slides, beads, and cylinders, respectively. Beads were the best-performing substrate as determined by the greatest degradation rate for the model organic compound, Allura Red AC. The beads and cylinders showed 58 and 51% degradation of Allura Red AC, respectively. Actinometry experiments revealed cylinders had the largest fluence rate of 0.0782 J·L−1 s−1. Optimization of the sol-gel application method and reactor operating parameters was performed to maximize the degradation rate and the overall degradation of Allura Red AC. Electric energy per order (EEO) was calculated and optimized at 9.20, 10.5, and 12.7 kWh·m−3 order−1 for the glass beads, cylinders, and slides, respectively.

Ozonated Water, Ozonated Water, Ozonated Oil and its Products

Ozonated Water, Ozonated Water, Ozonated Oil and its Products

Resonances of Surface Plasmons in an Elliptical Glass Cylinder Covered with a Layer of Silver

We study the plasmon resonances, which occur in the two-dimensional problem of diffraction of a plane wave on a glass cylinder encased in a silver layer, under the assumption that the media interface boundaries are confocal ellipses. Numerical methods are used to calculate the spectra of scattering and absorption in the optical wavelength range. The obtained analytical expressions allow determining the resonance parameters of the structure within the quasistatic approximation.

Segregation patterns in binary granular mixtures with same layer-thickness under vertical vibration

Inspired by the theoretical prediction [Phys. Rev. Lett. 86, 3423 (2001)] and the disputed experimental results [Phys. Rev. Lett. 89, 189601(2002), Phys. Rev. Lett. 90, 014302 (2003)] about the problem of granular segregation, we systematically investigate the pattern of binary granular mixtures consisting of same layer-thickness under vertical vibration. Various kinds of mixtures with different diameters and densities particles are poured into the glass cylinder that is sealed and evacuated to an air pressure less than 50Pa to observe separation patterns. It is found that these granular mixtures behave like five kinds of segregation patterns for different driving control parameters, i.e., Brazil nut (BN), reversed Brazil nut (RBN), Mixed states, light-BN (LBN), and light-RBN (LRBN). The latter two regimes are neither purely segregated nor completely mixed states. Moreover, BN phenomenon takes place in the area of low density ratio and found to be independent of layer-thickness, while RBN is sensitive to both the layer-thickness and frequency and occurs at the large density ratio area. Our result may be helpful for the establishment of theory about the segregation and mixing of granular mixtures.

Leaky modes of solid dielectric spheres

In the absence of external excitation, light trapped within a dielectric medium generally decays by leaking out (and also by getting absorbed within the medium). We analyze the leaky modes of a parallel-plate slab, a solid glass sphere, and a solid glass cylinder, by examining those solutions of Maxwell's equations (for dispersive as well as non-dispersive media) which admit of a complex-valued oscillation frequency. Under certain circumstances, these leaky modes constitute a complete set into which an arbitrary distribution of the electromagnetic field residing inside a dielectric body can be expanded. We provide completeness proofs, and also present results of numerical calculations that illustrate the relationship between the leaky modes and the resonances of dielectric cavities formed by a simple parallel-plate slab, a glass sphere, and a glass cylinder.

The diffusion coefficients of noble gases (He Ar) in a synthetic basaltic liquid: One-dimensional diffusion experiments

Diffusion coefficients of noble gases in silicate liquids are poorly known, and, as a result, it is difficult to quantify the importance of kinetic fractionation of noble gas abundances and isotopic compositions during magmatic processes. Nevertheless, diffusive fractionation has been invoked to explain noble gas signatures in MORBs and OIBs, with important implications for magma degassing and noble gas mantle geochemistry. In order to investigate the diffusion of noble gases in magmas, we developed an experimental protocol based on uniaxial diffusion of He and Ar through a column of synthetic basaltic liquid in a Pt tube. At the end of the experiment, the column of silicate liquid was rapidly quenched to a glass recording the diffusion profile. The glass cylinder was cut into a series of slices, which were analyzed for noble gases by traditional noble gas mass spectrometry following total gas extraction by fusion. Using this protocol, we measured He and Ar diffusivities in CMAS glass G1 (50 mol% SiO2, 9 mol% Al2O3, 16 mol% MgO, 25 mol% CaO) at temperatures of 1673 K and 1823 K: DHe = 2.75 ± 0.25 × 10− 6 cm2·s− 1 (T = 1673 K); DHe = 4.77 ± 0.42 × 10− 6 cm2·s− 1 (T = 1823 K); and DAr = 9.3 ± 1.3 × 10− 7 cm2·s− 1 (T = 1673 K). Combining these new high temperature data with diffusion coefficients measured on the same composition just above the glass transition temperature, we determined the activation energy Ea and the pre-exponential factor D0 for He and Ar diffusion in silicate liquids: D0 = 1.72 ± 0.9 × 10− 2 cm2·s− 1 and Ea = 136.5 ± 3.2 kJ/mol for Ar; D0 = 1.8 ± 0.5 × 10− 4 cm2·s− 1 and Ea = 57.6 ± 1.5 kJ/mol for He. Because He and Ar have very different activation energies for diffusion in the liquid state, the ratio DHe/DAr is strongly sensitive to temperature, decreasing from 145 at the glass transition temperature (1005 K) to 2 at 1823 K. The implication is that the kinetic fractionation of He relative to Ar in magmas is likely to be more important during the cooling stages than during the earlier, high temperature stages of magmatic history.

Mechanical study of the effect of fractional-wettability on multiphase fluid flow

Fractional wettability has been widely recognized in most of the oil reservoirs and it is a crucial factor that controls the fluid flow behavior in porous medium. The overall effect of the proportion of oil-wet grains on the fluid flow properties has been well discussed. However, recent studies found that the random distribution and coordination of oil-wet and water-wet grains could make multi-phase flow behaviors extremely complicated in such media. The multiphase flow mechanisms in fractional wettability media remains unclear. In this study, oil imbibition experiments were systematically conducted using glass cylinders packed with fractional-wet glass beads. To study the effect of fractional wettability on multiple-phase flow properties, samples with different oil-wet grain proportions were prepared, and fifteen repeated experiments were conducted for each oil-wet proportion. The experimental results showed that oil imbibition was largely dependent on but not strictly a function of the proportion of oil-wet grains in the medium. The imbibition behaviors of samples with the same fractional proportion could vary significantly, as some samples exhibited complete oil migration, while others did not. This probabilistic phenomenon is likely due to the random distribution of oil-wet and water-wet grains. A pore throat may behave as oil-wet or water-wet depending on the relative proportion of oil-wet grains the pore throat contains. When the grains that comprise the pore throat are dominated by oil-wet grains, the throat behaves as oil-wet, and vice versa. Only when these oil-wet pore throats are connected to form a complete oil-wet pathway throughout the medium can the oil continuously imbibe into the medium. Therefore, the extent of oil imbibition depends on the completeness of the oil-wet pathway, which is controlled by the proportion of oil-wet grains in the medium. The higher the proportion of oil-wet grains in the medium, the larger the number of oil-wet pore throats that can form; thus, the higher the possibility that those oil-wet pore throats can connect to form continuous oil-wet pathways.

Plasma Adaptive Optics Evaluation Using Two-Wavelength Heterodyne Interferometry

The third part of a research program that investigates the possibility of using low-temperature ionized air (plasma) for adaptive optics in an airborne laser directed-energy system is presented. It involves a novel optical measurement method that consists of a dual-wavelength Michelson interferometer that includes a microactuated mirror to allow heterodyne operation. The heterodyne interferometry is an important element in extracting the individual effects of electrons and heavy particles on the optical properties of the plasma. The plasma is generated in a hollow glass cylinder that is sealed at both ends by optical glass. It uses an ac voltage source for which the amplitude is modulated in order to produce sideband phase modulations for heterodyne analysis. A robust demodulation scheme is developed to extract the modulated interferometric phase shifts to reveal the temporal evolution of electron and heavy particle densities within the plasma. The contributions of the electron and heavy particle densities to the plasma optical path difference, which is a measure of optical control, are calculated. Based on an aero-optic standard wavelength, for the conditions examined in the experiment with air, the combined contributions yield an optical path difference of , which is two times larger than nominal optical path difference values in aero-optic applications.

Reverse Engineering Eighth Century C.E. Window Glass Processing at Sardis, Turkey

ABSTRACTFrom the early eighth century CE Byzantine shops next to the Synagogue and Bath-Gymnasium Complex at Sardis, Turkey, were excavated from 1958 to 1969 more than 50 pounds, or about 350 panes of transparent flat glass sheets interpreted as window glass. Examination using optical microscopy showed little variation in size, shape, thickness, edge shape, tool marks, bubble and cord elongation and alignment. Microstructural and compositional variation of weathered surfaces and unweathered cross sections were studied using scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDS). Differential thermal analysis (DTA) was used to determine glass transition temperature range. Three traditional window-forming methods have been described in the glass technology literature: crown, plate and cylinder. The Sardis glass is most similar to criteria expected for cylinder glass, but significant differences were documented. Consistently patterned characteristics evidence a developed technological practice. Replicative tests were conducted using various forming sequences. Wooden and ceramic two-piece molds were made to overblow one or both ends, and hot glass threads were used to thermal shock the cylinder ends and to make a vertical crack that allowed opening during a reheating and slumping operation. These reconstructed methods fit the observed microstructural and macrostructural characteristics of the glass sheets. Analysis of glass manufacturing methods in antiquity contribute to the historical knowledge of craft practices and to the interpretation of industrial debris excavated at markets and industrial workshops.

Effects of Some Chemicals on Vase Life of Some Cut Flowers I. Effect of 8-Hydroxyquinoline Sulfate, Silver Nitrate, Silver Nano Particles and Chitosan on Vase Life and Quality of Cut Rose Flowers (Rosa hybrida. Cv. “Black Magic”)

This investigation was carried out during 2015 and 2016 seasons to determine whether the selected chemical agents could be used to improve the postharvest quality of Rosa hybrida L.cv. “Black Magic” cut flowers. Freshly cut flowers were placed in glass cylinders containing 100 ml of preservative solutions [8-hydroxyquinoline sulfate (8-HQS) at 200 ppm, silver nitrate (AgNO3) at 10 ppm, Chitosan at 50, 75 or 100 ppm silver nano-particles (SN) at 5, 10 or 15 ppm, and distilled water as a control treatment].All preservative solutions and the control treatment included sucrose at 20 g/l. Compared to the control, treatments which contained of (AgNO3) or (SN) improved the quality and vase life of the flowers. They were more effective in promoting water uptake, increasing fresh weight of the flower and water balance so that the vase life of cut flowers were extended to 13.67 and 12 days during the first and second seasons, respectively. The results of bacterial count in the vase solution and the Scanning Electron Microscopy (SEM) pictures of the cut base of the stem indicated that (AgNO3) or (SN) strongly reduced bacterial population in both the vase solution and the cut stem base. The results indicated that using (AgNO3) or (SN) combined with 20 g/l sucrose could be used as a commercial cut flower preservative solution for prolonging the vase life and enhancing post-harvest quality of selected rose cut flowers.

Simulation parameters of temperature in the process of manufacturing a glass-metal composite

A mathematical model is proposed for solving the problem of the glass cylinder deformation under the action of temperature and pressure in a confined region. Experimental investigations were made to confirm modeling parameters.