Differences In Peak Intensities Research Articles

Links Between Steepened Mach Waves and Coherent Structures for a Supersonic Jet

The links between coherent structures in the shear layer of an isothermal Mach 2 jet and steepened Mach waves just outside the jet are investigated using large-eddy simulation. Conditional averages triggered by the detection of high-intensity pressure peaks on a conical surface near the jet flow are computed. Averages obtained for peaks of different intensities are presented to identify the factors favoring the steepened aspect of the waves, which are not likely due to nonlinear propagation effects given the surface radial position. The Mach waves just outside the jet are shown to be correlated with coherent structures in the supersonic side of the mixing layers. Their steepened aspect is found to increase with their intensity. The variations of the wave properties with the convection speed, strength, and geometrical shape of the mixing layer structures are then discussed. These properties do not depend much on the convection speed but are closely related to the two other parameters. The wave intensity and steepened aspect increase because the shear-layer structures are stronger, but also because they are more inclined relative to the jet direction. In the latter case, the asymmetric shape of the structure appears to promote the formation of positively skewed Mach waves.

Early evaluation of treatment response to transarterial chemoembolization in patients with advanced hepatocellular carcinoma: The role of dynamic three-dimensional contrast-enhanced ultrasound.

Dynamic three-dimensional contrast-enhanced ultrasound (3D-CEUS) with quantitative analysis is available in recent years. It can reduce the quantitative sampling error caused by the inconsistency of different sections in order to evaluate local treatment response of hepatocellular carcinoma (HCC) accurately. To investigate the value of dynamic 3D-CEUS in evaluating the early response to transarterial chemoembolization (TACE) treatment in patients with advanced HCC lesions. In this prospective study, both two-dimensional (2D) CEUS and dynamic 3D-CEUS were performed on 40 HCC patients who scheduled for TACE at baseline (T0) and 1-3 days (T1) after treatment. Tumor microvascular perfusion changes were assessed by CEUS time-intensity curve (TIC) and quantitative parameters. According to contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging 1 month after treatment results, patients were divided into responders and non-responders groups. The changes of perfusion parameters of both 2D-CEUS and 3D-CEUS were compared between responders and non-responders groups before and after TACE treatment. Before and after TACE treatment, no significant difference in maximum diameter of HCC lesions between the two groups could be found. There were more significant differences and ratios of perfusion parameters in 3D-CEUS quantitative analysis than in 2D-CEUS. The mutual significant differences and ratios of 2D-CEUS and 3D-CEUS included peak intensity (PI) difference, PI ratio, ratio of area under the curve (A), ratio of area under the wash-out part (AWO) and slope (S) difference. The former 4 corresponding parameters were better on 3D-CEUS than on 2D-CEUS. Dynamic 3D-CEUS can be used as a potential imaging method to evaluate early treatment response to TACE in advanced HCC patients.

Differential Scanning Calorimetry as a Method for the Control of Vegetable Oils

Differential scanning calorimetry (DSC) was used to study the thermophysical properties of oils of amaranth, corn, flax, sunflower, rapeseed, milk thistle, camelina, and pumpkin seed, liquid at room temperature. The characteristic thermal effects of these oils (temperatures of the maxima of endothermic peaks and their areas in the DSC thermograms) were determined. Endothermic peaks of different intensities on the melting curves of liquid vegetable oils in the ranges from –40 to –15°C, from –25 to –8°C, from –19 to +6°C, and from –10 to +4 °C as identification factors are discussed. The coordinates of the maxima of these peaks on the abscissa axis (Ti) and their areas (Si) significantly correlate with the concentrations of basic fatty acids and triacylglycerols (Wi, %), determined by reversed-phase HPLC. We demonstrated that the authenticity of vegetable oils could be effectively controlled by DSC.

Phytoremediation potential of some abundantly growing indigenous herbs of crude oil contaminated sites

Aim: To study the total oil and grease (TOGs) removal potential of three abundant herb species of crude oil contaminated sites, namely Xanthium strumarium (L.), Ageratum conyzoides (L.) and Polygonum hydropiper (L.) from oil contaminated soils. Methodology: The pot experiment was carried out by taking soil samples of crude oil contaminated agricultural field. For each experimental plant, three replicas were maintained and a similar control setup was maintained without plants for comparing the results. Another control set up was maintained in non-contaminated soils to compare the plant growth parameters. Total oil and grease (TOG) contents, physico-chemical profiles of contaminated soil, plant growth/productivity parameters and functional groups were analyzed following the standard methods. Results: The results showed that total oil and grease (TOG) contents decreased significantly after treatments by plants against the initial level and control. Plant height, number of leaves, chlorophyll contents and biomass were found to be lower in all the three plant species that were grown in contaminated soil as against the control treatment. The improved physico-chemical profiles of contaminated soil samples after treatment indicated the positive effect of plants in treated soil samples. FTIR data revealed difference in peak intensities and the presence of petroleum hydrocarbons in plants that were grown in oil-contaminated soils. Interpretation: The herb species Xanthium strumarium, Ageratum conyzoides and Polygonum hydropiper showed the potential for removal of hydrocarbons from crude oil contaminated soil. Key words: Crude oil, Hydrocarbons, Indigenous herbs, Phytoremediation

Study on crystalline phases and degree of crystallinity of the melt compounded PVA/MMT and PVA/PVP/MMT nanocomposites

Polymer nanocomposite (PNC) films comprised poly(vinyl alcohol) (PVA) and also its blend with poly(vinylpyrrolidone) (PVP) (i.e., PVA/PVP = 75/25 wt/wt%) as host matrices loaded with different amounts of montmorillonite (MMT) nanoclay up to 10 wt% were prepared by melt compounded method. X-ray diffraction (XRD) patterns of these PNC films were recorded in the appropriate angular range of 2θ values 3.8°–26° for their crystalline phase structural characterization. In comparison to the broader-type single diffraction peak for the aqueous solution cast prepared pure PVA film and that of the PVA/PVP blend film which is attributed to the hydrogen bonded isotactic and syndiotactic PVA crystals, five sharp diffraction peaks of different intensities corresponding to the evolution of various crystallites in the melt compounded PVA and PVA/PVP blend films were observed. Further, these peaks intensities were found significantly affected by the amounts of loaded MMT in these polymer matrices-based nanocomposites. It was observed that the prominent crystalline phase of the pure PVA converted into alternative tactic phases in the PVA/MMT films with the variation of MMT concentration. The prime crystalline phase of the PVA/PVP/MMT nanocomposites underwent alternative crystal structures formation abruptly on the initial loading of the 1 wt% amount of MMT in the PVA/PVP blend matrix reflecting a substantial alteration in the direction and nature of hydrogen bonding within the PVA crystal structures, and less changes were found with the further increase of MMT concentration up to 10 wt%. The effect of MMT loading on the crystallite sizes, degree of crystallinity, and the exfoliated and intercalated MMT structures in these PNC materials were analyzed in detail.

DIFFERENTIAL SCANNING CALORIMETRY OF LIQUID VEGETABLE

The thermophysical properties of vegetable oils were studied by differential scanning calorimetry method was used to study the fatty acid composition of vegetable oils liquid at room temperature, such as amaranth (Amaránthus), corn (Zea mays), flax (Línum usitatíssimum), sunflower (Helianthus), rape (Brusss napor), milk thistle (Sílybum mariánum), saffron milk cap (Camelina sativa) and pumpkin (Cucurbita pepo). The temperatures of the endothermic peak maxima and their area on the DSC thermograms of these oils were established as characteristic thermal effects. The interconnection between thermal effects and fatty acid composition are revealed. On the melting curves of liquid vegetable oils, up to 5 endothermic peaks of different intensities were selected in the ranges -80÷-55 °C, -40÷-15 °C, -25÷-8 °C, -19÷+6 °C and -10÷+4 °C. The coordinates of the maxima of these peaks (Ti) and their area (Si) significantly correlate with the content (Wi,%) in the oils, primarily oleic, linoleic and linolenic acids, the total proportion of which in oils is from 75 to 92%. Using the DSC thermograms of rapeseed oil as an example, it is shown that the program separation of DSC peaks allows a multiple increase in the number of analytical signals, an increase in the reliability of identification of the fat phase, and identification of the main fractions of triglycerides. DSC as a method for identifying vegetable oils using modern thermal analysis instruments is simple to sample, has good reproducibility and can be an independent method for identifying and controlling the quality of vegetable oils.

Artifacts in multilayer depth profiling: Origin and quantification of a double peak layer profile of Ag in ToF-SIMS depth profiles of an Ag/Ni multilayer

Depth profiles of a Ni/Ag multilayer with 25 nm nominal layer thickness obtained by Time-of-Flight Secondary Mass Spectrometry (ToF-SIMS) show the usual rounded top shape of the Ni layers, but a strange profile of Ag with two peaks of different intensities. Application of the Mixing-Roughness-Information depth (MRI)-model for quantification of both depth profiles revealed the fact that the only way to explain the measured Ag profile was the assumption of interfacial oxygen that promotes a strong matrix effect on the Ag ion intensity. Furthermore, it was demonstrated that the often applied normalizing of the elemental ions by the sum of the two ion intensities removes the double peak structure but results in a wrong quantification.

Untargeted-metabolomics differentiation between poultry samples slaughtered with and without detaching spinal cord

Chicken meat is among the common and relatively inexpensive source of protein consumed worldwide from the poultry industry. Many communities show concern regarding the procedure of slaughtering animals for meat consumption due to ethical, religious, or cultural reasons. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) based untargeted metabolomics of 40 chicken meat samples were evaluated to differentiate meat samples based on slaughtering methods. Samples were grouped into, Zabiha (cutting neck without detaching spinal cord) and Non-Zabiha (completely detaching neck). A volcano plot reveals at least 150 features found significantly different between the two groups having ≥ 2-fold changes in intensities with p-values ≤ 0.05. Among them 05 identified and 25 unidentified metabolites have clear differences in peak intensities. The identified features can be employed to differentiate meat obtained from different slaughtering methods. A characteristic pattern based on principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) was observed among the groups. The results will benefit Halal certification, food safety, and security agencies to curb food fraud.

Microstructural, rheological, gel-forming and interfacial properties of camel skin gelatin

Abstract The major challenge addressed in this study was to explore the effect of various extraction conditions for gelatin recovered from camel skin and investigate the effect on microstructural, rheological, gelation and interfacial properties. The results revealed that yield of gelatin extracted at high temperature (70 °C) was higher than that of gelatin extracted at low temperature (60 °C). However, the gel strength decreased with increase in extraction time from 5 to 9 h. Overall, it was found that gelatin extracted at 70 °C for 5 h displayed a very good gel strength (257 g) and high yield (14.1%). Protein patterns showed that all gelatin samples contained α1, α2 and β-chains. Structural analysis demonstrated that all gelatin samples showed a more or less similar spectrum with the presence of Amide I, II, amide III, Amide-A and Amide-B, but the intensity of different peaks were lowest at 70 °C and 9 h extraction conditions. Microstructural characterization revealed that gelatin extracted for 9 h displayed loose network with visible voids compared to those extracted for 5 and 7 h at both temperatures. Overall, gelatin extracted at 70 °C for 5 h displayed high gel strength, yield and compact microstructural features.

X-ray powder diffraction analysis of the phase composition of α- and near-α-titanium alloys

Titanium alloys are widely used as materials for the elements of nuclear power plants, which are subject to high reliability requirements. The goal of the study is to develop X-ray diffraction analysis of the phase composition of α - and near- α -titanium alloys. Surface treatment of the samples of titanium alloys PT-3V, PT-7M and VT1-0 was carried out by mechanical, electrochemical polishing and chemical etching. It is shown that PT-3V and PT-7M alloys are characterized by a mixed structure consisting of α - and α ’-phases with precipitation of submicron particles of the β -phase along the grain boundaries. The results of X-ray diffraction analysis of the samples obtained on an X-ray diffractometer Shimadzu XRD-7000 (Cu K α radiation) were compared with the data of metallography and electron microscopy. It is shown that the results of X-ray diffraction analysis strongly depend on the method, quality and duration of the surface treatment of the samples. Electrochemical polishing and acid treatment reduce the width of diffraction peaks and lead to a more pronounced manifestation of their «fine» structure thus demonstrating the presence of at least two crystalline phases in the alloys. «Splitting» of the main X-ray peaks of titanium is a consequence of the fine structure of primary X-ray radiation ( K α 1,2 -doublet). Presence of «fine» structure of X-ray peaks and correlation between the intensities of different peaks appears to depend essentially on the mode and quality of surface treatment of the titanium alloy thus reducing the reliability of quantitative analysis of the phase composition of titanium alloys without verification of the results by direct methods of studying alloy structure.

Effects of superfine grinding on the physicochemical properties and antioxidant activities of Sanchi (Panax notoginseng) flower powders.

Sanchi flowers were traditionally used as functional medicinal ingredient in materials. The study was aimed at evaluating superfine powder product of Sanchi flower, hence in this study, five fractions of dried Sanchi flower powders (SFP) were prepared at variable particle sizes by superfine grinding and evaluated for changes in various properties. Superfine powder with median particle diameter of 25.57μm was produced through grinding. It was evident from the environmental scanning electron microscopy analysis that during superfine grinding, mechanical shear stress played its crucial role in breakdown of the SFP and causes increases in surface area owing to reduction of particle sizes. Superfine grinding could improve solubility, oil holding capacity, and brightness, but decrease the fluidity of SFP. SFP with smallest particle size exhibited highest saponin, minerals, total phenolic, and flavonoid contents accompanied with the best antioxidant activities. Size reduction beyond M200 and M400 led to increasing tendency in IR signature band patterns and marked differences in peak intensities while the powdered samples showed resemblance with respect to peak shapes. Differential scanning calorimetry indicated the lowest melting temperature for SFP fraction with smallest particle size. Conclusively, superfine SFP due to inherent improvement in properties may render several potential applications in manufacturing of food and pharmaceutical additives to impart improved functionalities of finally finished products with uniformity.

In Ukrainian

This paper presents the results of studying by spectral methods (IR transmittance spectroscopy, diffuse reflectance (DR) spectroscopy, luminesce spectroscopy) of solidified solutions-melts of LaF3 and EuF3 in the saline system NaCl-KCl. A preliminary assessment of fluoride solubility on the basis of thermodynamic calculations of exchange reactions in the melt gave values of about 0.74 and 0.29% by weight, respectively, for LaF3 and EuF3 at 700°C. IR spectra of solidified solutions-melts contain a clear band in the range of 250-260 cm-1, corresponding to NaCl, and a less expressive band at 206-210 cm-1 (KCl). At the same time, the IR spectra of the undissolved residues also contain bands in the range of 360-390 cm-1, corresponding to the Ln – F bonds. The DR spectra of LaF3 in NaCl-KCl contain a deep band in the negative region at 245 nm, which corresponds to the intrinsic luminescence of NaCl, in the absence of its own absorption bands of La3+ ions. An analogous band is observed in the EuF3 DR spectra in NaCl-KCl, while it overlaps with the luminescence excitation band of Eu2+ at 350 nm. These bands are also contained in the DR spectra of the undissolved residue, while their intensity is much lower. In the range of 1800-2200 nm, in this case, the absorption band characteristic of Eu3+, consisting of several peaks of different intensities, also manifests itself. The possibility of a redox reaction between Eu3+ and Cl- ions is shown. The luminescence spectrum of LaF3 in saline melt is a broad band of middle intensity with a maximum at 460 nm. In the case of salt melt with EuF3, the luminescence band has the form of a rather narrow peak of high intensity with a maximum at 430-440 nm. In addition, a low-intensity emission band is detected, consisting of several peaks in the range of 500–700 nm, which is due to its appearance to 4f - 4f electronic transition in Eu3+. A similar absorption band takes place in the undissolved residue, while its intensity is much higher.

Quantitative Analysis of Near-Infrared Indocyanine Green Videoangiography for Predicting Functional Outcomes After Spinal Intramedullary Ependymoma Resection.

One of the most critical steps in surgery for spinal intramedullary ependymomas is the resection of small feeding arteries from the anterior spinal artery with anatomical preservation of the normal circulation of the ventral spinal cord. To quantitatively analyze the microcirculation of the ventral spinal cord by near-infrared indocyanine green videoangiography (ICG-VA) after the spinal intramedullary ependymoma resection. This retrospective study included 12 patients (7 male and 5 female; average age 55.2 years, range 36-79 years). Patients' neurological conditions were assessed based on the modified McCormick functional schema of grade 1 (neurologically normal) to 5 (severe deficit). Postoperative functional assessment was conducted at least 3 months after surgery. Quantitative analysis of vascular flow dynamics was carried out following spinal intramedullary ependymoma resection. Fluorescence intensities were measured and the indocyanine green (ICG) intensity-time curves were analyzed and compared with the functional outcomes after surgery. Microscopically total or subtotal resection of the intramedullary ependymoma was achieved in all cases. Average peak time on ICG-VA was significantly shorter in the postoperative functional grade 1 to 2 group than in the postoperative functional grade 3 to 5 group, but there was no significant difference in average peak intensity between the 2 groups. Postoperative functional grade and the peak time of ICG, but not peak intensity, appeared correlated. To the best of our knowledge, this is the first report showing that quantitative analysis of ICG-VA may predict functional outcomes after spinal intramedullary ependymoma resection.

Fast and robust phase-shift estimation in two-dimensional structured illumination microscopy

A method of determining unknown phase-shifts between elementary images in two-dimensional Structured Illumination Microscopy (2D-SIM) is presented. The proposed method is based on the comparison of the peak intensity of spectral components. These components correspond to the inherent structured illumination spectral content and the residual component that appears from wrongly estimated phase-shifts. The estimation of the phase-shifts is carried out by finding the absolute maximum of a function defined as the normalized peak intensity difference in the Fourier domain. This task is performed by an optimization method providing a fast estimation of the phase-shift. The algorithm stability and robustness are tested for various levels of noise and contrasts of the structured illumination pattern. Furthermore, the proposed approach reduces the number of computations compared to other existing techniques. The method is supported by the theoretical calculations and validated by means of simulated and experimental results.

Evaluation of crystallization technique relating to the physicochemical properties of cinnamic acid

In this study, the crystallization by anti-solvent and sonocrystallization were used for recrystallization of the cinnamic acid (CA), in order to evaluate the influence of these techniques on the modification of the solid-state properties and the aqueous solubility of the CA, since this has low aqueous solubility. The obtained crystals were characterized by differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermogravimetry (TG), powder X-ray diffraction, Fourier transform infrared spectrophotometry (FTIR) and scanning electron microscope (SEM). The effect of recrystallization was also evaluated by particle size and saturation solubility study. In general, the results showed that by the DSC, DTA and TG techniques, the thermal profile of the CA was not altered, as there were no chemical changes in the structure of the CA for the FTIR data, nor any major changes in the crystalline pattern of CA, only some differences in peak intensity. For the analyses of SEM and particle size, a more regular shape and a more even distribution of crystal size were observed after the crystallization process. A slight increase in CA solubility was observed when the solvents methanol and acetic acid were used. Therefore, it is possible to infer that the crystallization techniques used have given modifications in the properties of the solid state that can contribute to the improvement of technological characteristics of the powder favoring the use of CA in several pharmaceutical formulations.

Effect of beam shape and spatial energy distribution on weld bead geometry in conduction welding

The size of a projected beam onto a workpiece and its intensity distribution profile defines the response of the material to the applied laser heat. This means that not only the processing parameters, but also the optical set-up and process tools define the process and the resulting weld profile. In high power laser delivery systems the beam propagation characteristics of the laser beam can vary during processing. A change of the focal distance, for instance, alters the spot size projected on the workpiece as well as its intensity distribution. Some dynamic optical systems can also change the shape of the projected beam. Galvo-scanners induce a small distortion to the projected beam from circular to elliptical when the mirrors deflect the beam across the working domain. This continuous change of the spatial energy distribution may affect the process stability and material response locally. This work examines the influence of changing the shape of the projected beam and its energy distribution on the weld bead profile in conduction laser welding, which is also relevant to laser cladding and additive manufacture. It has been found that for the same optical set-up and system parameters, different bead profiles can be obtained with different degree of distortion of the beam profile. In addition, different intensity distribution profiles led to different penetration depths for the same nominal beam diameter and energy density due to the difference in peak intensity.

Application of ellipsometry, spr-technic and raman-spectroscopy into diagnosis of colorectal cancer

Experiments with application of the “Ellips-SPEK” spectral ellipsometric SPR (Surface Plasmon Resonance) analyzer, validating the results on the basis of ProteOn XPR36, revealed the differences in the values of velocity constants of specific interactions of monoclonal highly specific antibodies with tumor M2-pyruvate kinase on the surface of blood serum biochips in patients with various stages colorectal carcinoma (CRC) and location of metastases (AUC 0.89). Scanning ellipsometry enabled to reveal a significant increase of biomolecule surface effective thickness resulting from the specific “antigen-antibody” interaction in the group of patients with extrahepatic and hepatic metastases, as compared to the control group with healthy patients (p<0.0001–0.05). Raman spectroscopy of blood serum demonstrated the differences in peak intensity within the range of 1005–1520 cm-1 in the same groups of patients (p<0.0001–0.05) with a 90% predictive accuracy of the method applied at early stages of the disease. The results obtained can be used for development of methods for early diagnosis of CRC, localization of different metastases, relapses and control of the quality of administered therapy.

Label-free self-referenced sensing of living cells by terahertz metamaterial-based reflection spectroscopy.

Terahertz (THz) metamaterial-based reflection spectroscopy is proposed for label-free sensing of living cells by a self-referenced method. When sensing the living Madin-Darby canine kidney cell monolayer and phosphate buffered saline solution, self-referenced signals showed significant differences in peak intensity because of inherent discrepancy in the imaginary part of their complex refractive indices, as confirmed by 3D-FDTD simulations. The resonance peak intensity was unaffected by cell monolayer thickness variation, demonstrating feasibility for sensing various cells. Simulations and experiments showed that saponin-induced changes in cell permeability could be monitored in real-time. The self-referenced signal was linearly dependent on the adherent cell density, illustrating a label-free in situ THz metamaterial-based cell sensor.

Surface Engineering Effect on Optimizing Hydrogenation Timing of Green Hydrogenated Chitosan-Mediated CuO (H-Cht-CuO) for Cashew-kernel-oil Hydrogenation

The effect of polycrystallite surface engineering on the time required to fully hydrogenate green chitosan-mediated CuO to form hydrogenated chitosan-mediated CuO (H-Cht-CuO) as well as the catalytic properties of both CuO and H-Cht-CuO have been investigated. The prepared chitosan mediated CuO was obtained from the reaction of copper (II) sulphatepentahydrate with green alkali (aqueous extract of ripe plantain peel ash) <i>via</i> sol-gel technique (chitosan-gel mediated) and heated at 550°C for 6 h. The resultant sample was divided into two portions. The first was used as the control experiment (0 min) while the second was hydrogenated at varying times of 2 to 8 mins to form the H-Cht-CuO samples. A second CuO (control) without chitosan was also synthesized for structural and surface morphological comparisons with the chitosan-mediated using the XRD and SEM techniques, respectively. The XRD reflections showed differences in peak intensities with the chitosan-mediated having broader peaks while its SEM pores were 8.5 times larger than those of CuO (non chitosan-mediated). UV-Vis analysis of the samples showed that the 2 mins H-Cht-CuO sample had the maximum absorptivity while CuO (control-chitosan mediated) had the least. Both samples were used as catalysts in the hydrogenation of Cashew kernel oil. The GC-MS results showed that the Oleic acid component was reduced from 84.36% to 0.06% and 0%, Linoleic acid from 8.68% to 3.63% and 0% with increase in Stearic acid (saturated C₁₈) from 4.88% to 34.97% and 84.76% by the CuO and H-Cht-CuO, respectively.

Synthesis of composite thin-film polymer consisting of tungsten and zinc oxide as hydrogen gas detector

A composite polymer consisting of polyaniline (PANI) was synthesised via oxidative polymerisation by varying concentrations of transitional metal oxides and the presence of a hydrogen dissociation catalyst, palladium (Pd). The metal oxides chosen for this study were tungsten oxide (WO3) and zinc oxide (ZnO). The composite polymer samples were characterised using Fourier transform infrared (FTIR) spectroscopy where ultraviolet-visible (UV-Vis) spectroscopy was used to observe the optical changes of the thin films due to exposure to hydrogen. The FTIR spectra obtained confirmed the synthesis of PANI composite. Based on the UV-VIS analysis, PANI-ZnO composite polymer showed the highest difference in peak intensity before and after exposure to hydrogen with 11.4% difference.