Degradation and toxicity reduction of textile dyestuff by ultrasound

Degradability of four textile dyes was investigated in deionized water solutions during 520 kHz ultrasonic irradiation. It was found that for all dyes, the rate of color decay was first order in the visible absorption of the dye, and related to the type of functional groups that characterized the chromophore in the dye molecules. The destruction of aromatic/olefinic carbons in azo dyes was slower than that of color--to be attributed to the priority of hydroxyl radical attack on the N=N bonds, and to the formation of numerous oxidation intermediates of organic character during the course of dye degradation. Toxicity analysis of the dye solutions prior to sonolysis revealed that "reactive" dyes were non-toxic, but "basic" ones were toxic at the test concentrations employed in the study. Significant degrees of toxicity reduction were accomplished along with color and aromatic carbon degradation.     

Development and investigation of ultrasound linear phased arrays for transrectal treatment of prostate

We used the rectangular radiator method as a numerical solution to the Rayleigh-Sommerfeld diffraction integral for calculating the acoustic fields produced by linear arrays. The appropriate phases and amplitudes of voltages applied to the elements were computed using the pseudo-inverse method. We have developed and acoustically evaluated several constructions of planar linear ultrasound phased arrays for transrectal thermotherapy of prostate diseases. The designs of the linear phased arrays used in this work were the result of compromise in terms of the choice of frequency and number and size of elements, in order to investigate a means of improving array performance which might lead to increased efficacy and safety of the thermal treatment. The results obtained are in agreement with the data of other studies and show that a linear plane phased array may be potentially useful for thermal therapy.     

The effects of industrial airborne ultrasound on humans

Reported physiological effects resulting from the exposure of small animals to ultrasound cannot be transposed directly to man. There is no evidence of permanent biological changes, including hearing loss, as a result of normal industrial exposures to pure ultrasound, although some effects may occur as a result of experimental laboratory exposures. The high levels of high-frequency audible sound which accompany many industrial processes, particularly those producing cavitation, may cause unpleasant subjective effects, including headaches, nausea, tinnitus, and possibly fatigue in persons without hearing loss at those frequencies.     

Determination of the Klein-Cook parameter in ultrasound light diffraction

For weak and strong acousto-optic interaction analytical solutions are available which describe the diffraction problem. In the intermediate range between these limiting cases, however, the light-sound interaction is far more difficult to analyze for two reasons: (i) Only numerical approaches are available and (ii) the diffraction problem depends on two parameters: the Raman-Nath parameter and the Klein-Cook parameter. This paper describes a technique which makes possible the determination of the Klein-Cook parameter with an adequate accuracy for many fields of application. Once the Klein-Cook parameter is known, the Raman-Nath parameter can easily be obtained from numerical approaches.     

Mapping of an ultrasonic bath for ultrasound assisted extraction of mangiferin from Mangifera indica leaves

The present work deals with the mapping of an ultrasonic bath for the maximum extraction of mangiferin from Mangifera indica leaves. I₃⁻ liberation experiments (chemical transformations) and extraction (physical transformations) were carried out at different locations in an ultrasonic bath and compared. The experimental findings indicated a similar trend in variation in an ultrasonic bath by both these methods. Various parameters such as position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power which affect the extraction yield have been studied in detail. Maximum yield of mangiferin obtained was approximately 31 mg/g at optimized parameters: distance of 2.54 cm above the bottom of the bath, 7 cm diameter of vessel, flat bottom vessel, 6.35 cm liquid height, 122 W input power and 25 kHz frequency. The present work indicates that the position and depth of vessel in an ultrasonic bath, diameter and shape of a vessel, frequency and input power have significant effect on the extraction yield. This work can be used as a base for all ultrasonic baths to obtain maximum efficiency for ultrasound assisted extraction.     

Polarization-based range-gated imaging in birefringent medium:Effect of size parameter

We have investigated the effect of size parameter of the scatterer on the image quality obtained with polarization-based range-gated imaging in birefringent turbid medium. Both linearly and circularly polarized light were utilized for imaging.The simulated results indicate that the improvement of visibility is more pronounced using circularly polarized light for the birefringent medium composed of smaller-sized scatterers at lower values of optical thickness and the birefringent medium comprising larger-sized scatterers. In contrast, linearly polarized light provides better image quality for the birefringent medium composed of smaller-sized scatterers at larger values of optical thickness. The evolution of the polarization characteristics of backscattered light and target light under the conditions mentioned above was measured to account for these numerical results.     

A novel ultrasound instrument for investigation of arterial mechanics

The study of arterial mechanics concerns functional characteristics depending on wall elasticity and flow profile. Wall elasticity can be investigated through the estimation of parameters like the arterial distensibility, which is of high clinical interest because of its known correlation not only with the advanced atherosclerotic disease, but also with aging and major risk factors for cardiovascular disease. The flow velocity profile is also clinically relevant, because it modulates endothelial function and can be responsible for the development and distribution of atherosclerotic plaques. A clinically relevant variable extracted from the blood velocity profile is the wall shear rate (WSR), which represents the spatial velocity gradient near the vessel wall. This paper describes an integrated ultrasound system, capable of detecting both the velocity profile and the wall movements in human arteries. It basically consists of a PC add-on board including a single high-speed digital signal processor. This is dedicated to the analysis of echo-signals backscattered from 128 range cells located along the axis of the interrogating ultrasound (US) beam. Echoes generated from the walls (characterized by high amplitudes and low Doppler frequencies) and from red blood cells (characterized by low amplitudes and relatively high Doppler frequencies) are independently processed in real-time. Wall velocity is detected through the autocorrelation algorithm, while blood velocity is investigated through a complete spectral analysis of all signals backscattered by erythrocytes and WSR is extracted from the estimated velocity profile. Preliminary applications of the new system, including the simultaneous analysis of blood flow and arterial wall movement in healthy volunteers and in a diseased patient, are discussed, and first results are presented.     

A theoretical investigation of chirp insonification of ultrasound contrast agents

A theoretical investigation of second harmonic imaging of an Ultrasound Contrast Agent (UCA) under chirp insonification is considered. By solving the UCA’s dynamical equation analytically, the effect that the chirp signal parameters and the UCA shell parameters have on the amplitude of the second harmonic frequency are examined. This allows optimal parameter values to be identified which maximise the UCA’s second harmonic response. A relationship is found for the chirp parameters which ensures that a signal can be designed to resonate a UCA for a given set of shell parameters. It is also shown that the shell thickness, shell viscosity and shell elasticity parameter should be as small as realistically possible in order to maximise the second harmonic amplitude. Keller-Herring, Second Harmonic, Chirp, Ultrasound Contrast Agent.     

Finite element modeling and intravascular ultrasound elastography of vulnerable plaques: parameter variation

BACKGROUND AND GOAL: More than 60% of all myocardial infarction is caused by rupture of a vulnerable plaque. A vulnerable plaque can be described as a large, soft lipid pool covered by a thin fibrous cap. Plaque material composition, geometry, and inflammation caused by infiltration of macrophages are considered as major determinants for plaque rupture. For diagnostic purposes, these determinants may be obtained from elastograms (i.e. radial strain images), which are derived from intravascular ultrasound (IVUS) measurements. IVUS elastograms, however, cannot be interpreted directly as tissue component images, because radial strain depends upon plaque geometry, plaque material properties, and used catheter position. To understand and quantify the influence of these parameters upon measured IVUS elastograms, they were varied in a finite element model (FEM) that simulates IVUS elastograms of vulnerable plaques. MATERIALS AND METHODS: IVUS elastography measurements were performed on a vessel mimicking phantom, with a soft plaque embedded in a hard wall, and an atherosclerotic human coronary artery containing a vulnerable plaque. Next, FEMs were created to simulate IVUS elastograms of the same objects. In these FEMs the following parameters were varied: Young's modulus (E), Poisson's ratio (nu) in range 0.49-0.4999, catheter position (translation of 0.8 mm), and cap thickness (t) in range 50-350 microm. Hereby the resulting peak radial strain (PRS) was determined and visualized. RESULTS: Measured static E for phantom was 4.2 kPa for plaque and 16.8 kPa for wall.Variation of E-wall in range 8.4-33.2 kPa and/or E-plaque in range 2.1-8.4 kPa using the phantom FEM, gave a PRS variation of 1.6%, i.e. from 1.7% up to almost 3.3%; for variation in nu this was only 0.07%, i.e. from 2.37% up to 2.44%. Variation of E-lipid in range 6.25-400 kPa and E-cap in range 700-2300 kPa using the artery FEM, gave a PRS variation of 3.1%, i.e. from 0.6% up to 3.7%. The PRS was higher for lower E-lipid and E-cap; it was located at a shoulder of the lipid pool. Variation of nu gave only a variation of 0.17%. Variation of t and E-cap resulted in a PRS variation of 1.4%, i.e. from 0.3% up to 1.7%; thinner and weaker caps gave higher PRS. Catheter position variation changed radial strain value. CONCLUSIONS: Measured IVUS elastograms of vulnerable plaques depend highly upon the Young's modulus of lipid and cap, but not upon the Poisson's ratio. Different catheter positions result in different IVUS elastograms, but the diagnostically important high strain regions at the lipid shoulders are often still detectable. PRS increases when cap weakens or cap thickness decreases.     

Plasma surface treatment of textile fibres for improvement of car tires

A new low-temperature plasma surface modification of advanced polyester tire cord at atmospheric pressure was tested. Plasma surface treatment was performed in the barrier discharge plasmas (BDPs, atmospheric pressure glow discharge (APG) and plasma of gliding are (Glid Arc). The surface properties were characterized by the electron spin resonance spectroscopy (ESR), measurements of the contact angle of various polar and non-polar liquids with polyester cords, H-test, peel test and partially by zeta potential measurements. Further tests have been performed at an industrial testingimpregnation line where the common technology was applied on both plasma treated and untreated fibres. The standard H-test and peel-tests were used to characterize the adhesion of the fibre to usual testingrubbers.     

紧凑高重复频率加速器的初级能源

介绍了一种输出脉冲峰值功率在GW量级,脉宽约6 ns,重复频率1~300 Hz可调的加速器的初级能源系统的设计与实验研究。它的初级能源由商用三相电源供能,利用硅堆整流,并通过固体开关及继电器等装置控制来实现对Tesla变压器初级线圈的重复谐振充电。实验表明该装置运行稳定,通过变压器升压之后可在120 W负载端得到300 kV的重复高电压脉冲。同时,该回路还利用了晶闸管拥有的自关断特性实现了能量的回收,提高了装置的能量利用率。     

The investigation of equations for the generalized order parameter in magnetic systems

Equations for the generalized order parameter in the presence of a disordered magnetic system are obtained in the framework of the exchange interaction model. The possibility of the occurrence of a superconducting state upon the destruction of an unstable soliton near the phase transition is considered.     

Simple treatment of cotton textile to impart high water repellent properties

We describe two methods to impart the water repellency for the surface of cotton fabric, using a commercially available and a laboratory synthesized fluoroalkylsiloxanes. To characterize the wettability and the durability of water repellent properties of hydrophobic coating produced, we have studied the advancing water contact angles, rolling angles and the evolution of water contact angle in time during a continuous contact of the surface with the water drop. The quality of the coatings was also assessed after the washing procedure. The analysis of the wettability of hydrophobized fabrics indicated that a better effect, leading to the superhydrophobic state of the surface, was observed when the surface relief of the fabric with the coating is determined by not only the structure and braiding of the fabric, but also the additional elements of texture created by the aggregates of molecules of hydrophobic agent.     

Influence of surface treatment on the electroless nickel plating of textile fabric

The present study is performed with an objective to acquire a deeper understanding of the properties of nickel-plated polyester fabric after conducing low temperature plasma treatment. Low temperature plasma treatment with oxygen and argon gases was employed to render a hydrophilic property of woven polyester fabrics and facilitate the absorption of a palladium catalyst in order to provide a catalytic surface for electroless nickel plating. The properties of plasma-induced electroless nickel-plated polyester fabrics were evaluated by various standard testing methods in terms of both physical and chemical performances.     

Nonlinear dynamics investigation in parameter planes of a periodically forced compound KdV-Burgers equation

Parameter plane plots related to a periodically forced compound Korteweg-de Vries-Burgers system, which is modeled by a third-order partial differential equation, are reported. It is shown that typical periodic structures embedded in a chaotic region in these parameter planes, organize themselves in different ways. There are bifurcation sequences whose periods have a well-defined law of formation, that may be written in a closed form, and there are bifurcation sequences self-organized in period-adding cascades.     

Study of the sonophotocatalytic degradation of basic blue 9 industrial textile dye over slurry titanium dioxide and influencing factors

The sonophotocatalytic degradation of basic blue 9 industrial textile dye has been studied in the presence of ultrasound (20 kHz) over a TiO(2) slurry employing an UV lamp (15 W, 352 nm). It was observed that the color removal efficiency was influenced by the pH of the solution, initial dye concentration and TiO(2) amount. It was found that the dye degradation followed apparent first order kinetics. The rate constant increased by decreasing dye concentration and was affected by the pH of the solution with the highest degradation obtained at pH 7. The first order rate constants obtained with sonophotocatalysis were twofold and tenfold than those obtained under photocatalysis and sonolysis, respectively. The chemical oxygen demand was abated over 80%.     

The application of high frequency ultrasound waves to remove ammonia from simulated industrial wastewater

This article aims at applying the ultrasound technique in the field of clean technology to protect environment. The principle of ultrasound was conducted here to remove and recover ammonia from industrial wastewater. Three different concentrations of ammonia namely 5%, 15% and 25% (vol.%) were used to study the efficiency of removing ammonia from water. These concentrations are exactly similar to what may be found in wastewater resulting from strippers at petroleum refinery. High ultrasound frequency device with 2.4 and 1.7 MHz was conducted to study the effect of waves on the removal of ammonia. It was found that the ultrasound has the ability to remove ammonia with 5% concentration to meet the local standard of treated wastewater within less than 2 h for 0.080 L solution. It was also found that as the concentration of the ammonia increases the removing of ammonia within 2 h decreases, still the concentration of the ammonia meets the standard of the treated wastewater. The ability of the ultrasound to remove the ammonia failed to produce any mist when the height of the liquid solution increased, namely when the height reached (0.0337 m). This is equivalent to liquid volume of 0.150 L. It means that the device capacity to remove ammonia has certain limitations based on liquid heights. The best condition for ammonia removal was obtained at 5% concentration and 0.080 L liquid volume (equivalent to 0.0165 m).     

Plasma treatment of polypropylene fabric for improved dyeability with soluble textile dyestuff

The impact of plasma treatment parameters on the surface morphology, physical-chemical, and dyeing properties of polypropylene (PP) using anionic and cationic dyestuffs were investigated in this study. Argon plasma treatment was used to activate PP fabric surfaces. Activated surfaces were grafted different compounds: 6-aminohexanoic acid (6-AHA), acrylic acid (AA), ethylendiamine (EDA), acryl amide (AAMID) and hexamethyldisiloxane (HMDS). Compounds were applied after the plasma treatment and the acid and basic dyeing result that was then observed, were quite encouraging in certain conditions. The possible formed oxidizing groups were emphasized by FTIR and ATR and the surface morphology of plasma treated PP fibers was also investigated with scanning electron microscopy (SEM).PP fabric could be dyed with acid and basic dyestuffs after only plasma treatment and plasma induced grafting, and fastnesses of the dyed samples were satisfactory.