CSD Method Research Articles

Electrostatic spraying for fine-tuning particle dimensions to enhance oral bioavailability of poorly water-soluble drugs

While spray-drying has been widely utilized to improve the bioavailability of poorly water-soluble drugs, the outcomes often exhibit suboptimal particle size distribution and large particle sizes, limiting their effectiveness. In this study, we introduce electrostatic spraying as an advanced technology tailored for poorly water-soluble drugs, enabling the fabrication of nanoparticles with fine and uniform particle size distribution. Regorafenib (1 g), as a model drug, copovidone (5 g), and sodium dodecyl sulfate (0.1 g) were dissolved in 200 ml ethanol and subjected to conventional-spray-dryer and electrostatic spray dryer. The electrostatic spray-dried nanoparticles (ESDN) showed smaller particle sizes with better uniformity compared to conventional spray-dried nanoparticles (CSDN). ESDN demonstrated significantly enhanced solubility and rapid release in water. In vitro studies revealed that ESDN induced apoptosis in HCT-116 cells to a greater extent, exhibiting superior cytotoxicity compared to CSDN. Furthermore, ESDN substantially improved oral bioavailability and antitumor efficacy compared to CSDN. These findings suggest that ESD shows potential in developing enhanced drug delivery systems for poorly water-soluble drugs, effectively addressing the limitations associated with CSD methods.

Local contribution to the somatosensory evoked potentials in rat's thalamus.

Local Field Potential (LFP), despite its name, often reflects remote activity. Depending on the orientation and synchrony of their sources, both oscillations and more complex waves may passively spread in brain tissue over long distances and be falsely interpreted as local activity at such distant recording sites. Here we show that the whisker-evoked potentials in the thalamic nuclei are of local origin up to around 6 ms post stimulus, but the later (7-15 ms) wave is overshadowed by a negative component reaching from cortex. This component can be analytically removed and local thalamic LFP can be recovered reliably using Current Source Density analysis. We used model-based kernel CSD (kCSD) method which allowed us to study the contribution of local and distant currents to LFP from rat thalamic nuclei and barrel cortex recorded with multiple, non-linear and non-regular multichannel probes. Importantly, we verified that concurrent recordings from the cortex are not essential for reliable thalamic CSD estimation. The proposed framework can be used to analyze LFP from other brain areas and has consequences for general LFP interpretation and analysis.

Chemical solution deposition of a (GaAl)2O3 single layer with high thickness and silver-enhanced crystal quality

A new study presents a revolutionary CSD method to create thick (180 nm) single-layer (GaAl)2O3 films with enhanced crystal quality through silver doping.

Comparison of Structural and Optical Properties of CdSe Films Grown by CSD and CBD Methods

Comparison of Structural and Optical Properties of CdSe Films Grown by CSD and CBD Methods

ANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS

ANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS. Ferroelectric materials, one of which is Barium Strontium Titanate (BST), can be applied for photovoltaic. Ferroelectric films function as the P-type semiconductor in the P-N junction. BST (Ba0.95Sr0.05TiO3) films have been deposited on Pt/Si (111) and quartz substrates via the CSD method prepared by spin coater. The films were annealed at various temperatures of 800 °C, 900 °C, and 1000 °C to observe the annealing temperatures' effects on the microstructure and optical properties of the BST films. From the XRD results, the intensity of diffraction peaks gets higher along with the higher annealing temperature. It thus causes the level of crystallization and the crystal size of the Ba0.95Sr0.05TiO3 films to increase. The morphology results reveal that the grains size of the Ba0.95Sr0.05TiO3 films is getting larger with the higher annealing temperature. The optical properties examined in the Ba0.95Sr0.05TiO3 films include absorbance and bandgap energy values. Values of bandgap energy show a decrease with increasing sintering temperature. The smallest bandgap energy of the Ba0.95Sr0.05TiO3 film is achieved at 1000 °C of 3.20 eV. BST films were annealed at temperature 1000 °C attained from this study can be considered as candidate for a photovoltaic ferroelectric material.

Polarization behavior of` lead-free 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 thin films with enhanced ferroelectric properties

(Bi0.5Na0.5)TiO3 based ferroelectric lead-free thin films have great potential for modern micro-devices. However, the multicomponent feature and volatile nature of Bi/Na makes the achievement of high quality films challenging. In this work, the morphotropic phase boundary composition, 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 thin films were successfully prepared by CSD method. Dense films with low dielectric loss and low leakage current density were obtained. A well-defined polarization hysteresis loop with a high remnant polarization was observed in the thin films. Moreover, the polarization behavior of the film at original state, under electric field and upon heating was investigated by PFM. A self-polarization and asymmetric domain switching behavior were observed. High temperature induced depolarization and the self-polarization recovered upon cooling. The thin films with good quality show a promising potential for the application in electrical devices, and the in-depth investigation of the polarization behavior improves the understanding of ferroelectric and piezoelectric properties of thin films.

Combined Use of Graphical and Statistical Approaches for Analyzing Historical Precipitation Changes in the Black Sea Region of Turkey

Many statistical methods have been developed and used over time to analyze historical changes in hydrological time series, given the socioeconomic consequences of the changes in the water cycle components. The classical statistical methods, however, rely on many assumptions on the time series to be examined such as the normality, temporal and spatial independency and the constancy of the data distribution over time. When the assumptions are not fulfilled by the data, test results are not reliable. One way to relax these cumbersome assumptions and credibilize the results of statistical approaches is to make a combined use of graphical and statistical methods. To this end, two graphical methods of the refined cumulative sum of the difference between exceedance and non-exceedance counts of data points (CSD) and innovative trend analyses (ITA)-change boxes alongside the classical statistical Mann–Kendall (MK) method are used to analyze historical precipitation changes at 16 stations during 1960–2015 in the Black Sea region of Turkey. The results show a good match between the results of the graphical and statistical methods. The graphical CSD and ITA methods, however, are able to identify the hidden trends in the precipitation time series that cannot be detected using the statistical MK method.

Application of barium strontium titanate (BST) as a light sensor on led lights

Barium Strontium Titanate (BST) film has been successfully produced as a light sensor. The BST film was made by CSD method by reacting barium acetate, strontium acetate and titanium isopropoxide with mole fractions of 0.5; 0.5 and 1, respectively.The BST absorbance test showed that BST film is sensitive to visible light ranging from 475 to 750 nm. The film test showed maximum absorbance at three peak wavelengths, 475 nm, 593 nm, and 702 nm. The energy gap of the BST film was 1.9 eV which showed that the film produced was a semiconductor. The IV test showed that BST film is a photodiode. This was indicated by the shift of the curve when tested in light and dark conditions. The sensitivity test showed BST film is most sensitive to blue light, signified by the most significant change in resistance. The decrease in resistance of blue LED was 0.401KΩ/lux, while the resistance decrease of green light was 0.051KΩ/lux and red was 0.288KΩ/lux. By using optical and electrical properties, BST thin film could be used as light sensors to detect LED lights.

Surface Morphology Properties Doped RuO2 (0, 2, 4, 6%) of Thin Film LiNbO3

Successful LiNbO3 film was prepared with the variation of 0%, 2%, 4%, and 6% RuO2 concentration and annealing temperature variation above the p-type silicon substrate (100), using the CSD method with the spin coating at 8000 rpm for 30 seconds in solubility 2 M. Films in annealing at 850 °C for 8 hours with a temperature increase of 1.67 C/min. Samples were characterised using SEM and EDX spectrometer. We have obtained the morphology nonhomogenous surface and element stoichiometry. LiNbO3 thin film is a potential material for light sensors.

Rapid Pyrolysis of YBa2Cu3O7-δ Films by Fluorine-Free Polymer-Assisted Chemical Solution Deposition Approach

A rapid pyrolysis heat treatment was proposed to prepare YBa2Cu3O7-δ (YBCO) films by a self-developed fluorine-free polymer-assisted chemical solution deposition (PA-CSD) approach. Metal acetates and polyvinyl butyral (PVB) in YBCO wet films were pyrolyzed within 30 min, which is less than one-twentieth the pyrolysis time for conventional fluorine–free CSD methods. The influence of the rapid decomposition on the microstructures of YBCO precursor films was investigated compared to conventionally pyrolyzed films. Based on the rapidly pyrolyzed films, high-temperature firing process was further optimized to fabricate epitaxially grown YBCO films. The results demonstrate that most of the defects generated in the rapid pyrolysis process can nearly be eliminated by extending firing time to 2 h, and thus the textured YBCO films with denser and smoother morphologies were obtained with superconducting transition temperature Tc of 93.3 K and critical current density Jc of 3.1 MA/cm2 at 77 K and self-field. This is almost three times of the Jc of the conventionally pyrolyzed film.

A CFD/CSD coupled method with high order and its applications in flow induced vibrations of tube arrays in cross flow

Wear and tear are the most common failures of tubes in cross-flow during long time operation of a steam generator due to the fluid induced vibrations. A fluid-elastic approach with high order was developed by coupling the CFD method and the CSD method. In the method, fluid forces were predicted by the CFD method followed by structural response calculations, and data were transferred via fluid-structure interaction interface. The unsteady flow through normal triangular cylinder arrays with one single tube undergoing self-excited oscillations was simulated by the proposed method. Lifts, displacement and velocity of the particular cylinder were obtained followed by calculations of the corresponding frequency spectrums. Results showed that the proposed method can predict the flow induced vibrations with high accuracy. When the natural frequency of the cylinder increased to the dominant frequency of the flow, an abrupt increment of vibrational velocity was observed.

A Strain Based Method for Determining the Crack Closure and Initiation Stress in Compression Tests

The pre-peak loading stages of rock in compression tests are divided into four stages (i.e., crack closure, elastic deformation, stable crack growth and unstable crack growth) by identifying the Crack Closure stress (CC), Crack Initiation stress (CI), and crack damage stress. A new method for determining the CC and CI is presented in this paper and compared with previous methods. The new method is called “Continuous Strain Deviation” (CSD), and it solves two problems associated with other methods: 1) determining the limits for the elastic range in laboratory data, and 2) identifying where crack closure or initiation occurs from the subtle changes in the stress-strain data. Starting from an initial point corresponding to 30% to 40% UCS, the proposed algorithm provides a distinct indicator for CC and CI. The CC and CI for Badaling granite and Äspö diorite are determined with the proposed method, results from which are similar to other methods. Sensitivity analyses of the CSD method show that stable CC and CI values could be estimated using any initial point from 30% to 40% UCS. Comparison studies show that the CSD method predicts a smaller stress range and gives a more distinct indicator for both CC and CI.

Numerical Simulation of Horizontal Axis Wind Turbines with Vortex Generators

In the present study, a simulation about the effects of vortex generators on horizontal axis wind turbine rotor blade was numerically conducted using a static coupled CFD–CSD method. A Navier–Stokes CFD flow solver based on unstructured meshes was used to obtain the blade aerodynamic loads. A FEM-based CSD solver employing a nonlinear coupled flap-lag-torsion beam theory was utilized to calculate the blade elastic deformation. The coupling of the CFD and CSD solvers was accomplished in a loosely coupled manner by exchanging the information between the two solvers at infrequent intervals. The static coupled CFD–CSD method was applied to the NREL 5 MW reference wind turbine rotor under steady axial flow conditions. Triangular counter-rotating vortex generators were adopted to control flow separation and radial flow in the inboard section of the NREL 5 MW reference rotor blades. They were installed on the inboard part of the blade from 0.2 to 0.4 R. As a result of the flow analysis considering the counter-rotating vortex generators, strong vortices were generated by counter-rotating vortex generators. It can be seen that the regions where flow separation and radial flow occur in the inboard sections were reduced compared to the baseline wind turbine. For this reason, the maximum power improvement due to counter-rotating vortex generators was 1.04% at the rated wind speed.

Resistive switching and ferroelectric properties in BiFeO3 superlattice films

Bi0.89Ho0.08Sr0.03Fe0.97−aMn0.03NiaO3/Bi0.89Ho0.08Sr0.03Fe0.97−bMn0.03NibO3 (Nia/Nib) superlattice films were prepared via a CSD method. The influences of interface effects on ferroelectric properties and resistance switching behaviors of the superlattice films were investigated. There was a weak interface effect in the superlattice films, which was caused by the misfit dislocation generated at the interfaces between Nia and Nib. The results indicate that the superlattice films show superior ferroelectric properties and good resistance switching behaviors, which is caused by the interface effect. Those superlattice films may have potential applications in multifunctional devices due to their excellent electric properties.

Role of ferroelectric/ferromagnetic layers on the ferroelectric properties of magnetoelectric composite films derived by chemical solution deposition

Composite thin films with BiFeO3 (BFO), CoFeO4 (CFO) and/or BaTiO3 (BTO) layers as the components are fabricated via CSD method. XRD and Raman patterns show all the composite films can be indexed to perovskite and spinel structures. Except the interfaces between BTO and CFO layers, the other two-phase interfaces can be clearly observed. Interestingly, the BTO-CFO film has bigger polarization than BTO-BFO, especially the thickness of CFO layer is smaller than the BFO layer, implying the ferromagnetic layer has a significant impact on the ferroelectric properties of the composite films, which is too thin to be fully polarized. The variation of leakage currents show BTO-CFO film has the smallest value, corroborating the results of ferroelectric measurements. The leakage current is dominated by the space-charges-limited mechanisms according to the fitting results, and the oxygen vacancies in the BFO layers play an important role for the variations of ESCL and ETFL voltages.

Epitaxial superconducting GdBa2Cu3O7−δ/Gd2O3 nanocomposite thin films from advanced low-fluorine solutions

We have employed the CSD method to synthesize GdBCO and GdBCO–Gd2O3 nanocomposite 250–300 nm thin films. For this we have designed a new low-fluorine solution never used before in the synthesis of GdBCO thin films that allows us to reduce the HF release by 80% and increase the reproducibility of the pyrolysis process. The growth of these thin films required a new thermal process to be designed, which we refer to as ‘flash-heating’, where the heating rate is extremely fast (∼600 °C min−1). The structure and the superconducting properties of the pristine GdBCO films are excellent, showing a (00 l) epitaxial orientation of the GdBCO grains and Tc values that reach 92.8 K, which means an enhancement of more than 1 K with respect to standard YBCO films. The calculated Jc inside the grains () also presents remarkable values: (5 K) ∼ 40 MA cm−2 and (77 K) ∼ 3.3 MA cm−2. Finally, the GdBCO–Gd2O3 nanocomposites films, with a 20% mol of Gd2O3, exhibit superior superconducting properties and pinning performances with respect to GdBCO pristine films.

Comparison XRD pattern of CoFe2O4 thin films and nanoparticles

In this study, preparation of CoFe2O4 coated film on glass using CSD method with spin coating technique. The films deposition were carried out at room temperature. The angular velocity on the spin coating process of CoFe2O4 films was selected for 1000 and 3000 rpm. The CoFe2O4 thin film was deposited using CoFe2O4 nanoparticles powder. The X-ray Diffraction (XRD) was utilized to characterizing of crystal structures. The XRD analysis of CoFe2O4 thin films was compared with the CoFe2O4 nanoparticles produced and resulting the exact same spectral. The result of XRD spectral corresponds to peak data from ICDD number 221086 that indicating the sample formed was CoFe2O4 with inverse spinel face center cubic (FCC) structure. Furthermore, the intensity of CoFe2O4 nanoparticles was greater than CoFe2O4 thin film. The crystallite size of the CoFe2O4 thin films sample with 1000 rpm obtained 70.6347 nm with the strain 0.00160, whereas for 3000 rpm it was obtained 60.5354 nm with the strain 0.00187.

Influence of magnetic annealing on the ferroelectric and dielectric properties of BaTiO3–CoFe2O4 multilayer films prepared by chemical solution deposition

BaTiO3–CoFe2O4 multilayer thin films with different thickness are deposited on Pt/Ti/SiO2/Si (100) substrates via CSD method. The magnetic annealing effect on the ferroelectric and dielectric properties of the multilayer thin films are investigated. It is found that both the ferroelectric and dielectric properties of the films are improved by the magnetic annealing. The changes of these two properties can be explained based on the variations of grain size, grain boundary, internal stress/strain as well as domain wall motion. A serial capacitor model is also used to analyze the influence of magnetic annealing on the dielectric properties. Leakage current densities are decreased after magnetic annealing and then fitted and explained with different leakage conduction mechanisms. Finally, comparing the ferroelectric and dielectric properties of the films with and without magnetic annealing, it can be concluded that the magnetic annealing effect is more significant on the thinner films.

Orientation-controlled BaTiO3 thin films fabricated by chemical solution deposition

We synthesized orientation-controlled (100), (110), and (111) BaTiO3 films by the CSD method and revealed the dielectric properties the films.

Aeroelastic analysis of wind turbines using a tightly coupled CFD–CSD method

This paper presents aeroelastic analyses of wind turbines, using the compressible flow Helicopter Multi-Block (HMB2) solver of Liverpool University, coupled with a Computational Structural Dynamics method. For this study, the MEXICO and NREL Phase VI wind turbines were employed. A static aeroelastic method was first employed for the analysis of the MEXICO blade and the effect of the torsional stiffness was studied at 10, 15 and 24m/s axial wind speeds. The torsional deformations showed strong dependency on this parameter and the blade region from mid-span to the tip was the most susceptible to aeroelastic effects. The work progressed by studying both the static and dynamic response on the NREL wind turbine, where the nacelle and the tower were considered. Mean deflections between the static and dynamic methods showed consistency and, due to the structural properties of this blade, flapping modes were dominant. The dynamic aeroelastic method enabled an assessment of the effect of flapping on the blade loads, in conjunction with the effect of tower. Aeroelastic effects were found to be secondary for the MEXICO blade, but had a stronger effect on the larger NREL Phase VI blade.