Clear Layer Research Articles

Exploration of Shape Memory Polymer for Automotive Coating Applications

Shape memory polymer (SMP) is one special kind of polymer which can recover back to permanent shape after being mechanically deformed. As for automotive coating, most of the defects occurs on the clear coat layer, if it can be replaced by shape memory polymer, the defects can be easily removed due to the self-healing ability of shape memory polymer. In this experiment, the self-healing ability of epoxy based shape memory polymer thin lm (around 100μm) is examined. Five indents on the thin lm shape memory polymer with depths from 4.9μm to 5.5μm are all disappeared after 15 minutes heating at 70 o C. The average hardness of the polymer is 165 ± 2MPa and the modulus is 5.76 ± 0.02GPa (assume Possion’s ratio 0.4).

High performance FeSe0.5Te0.5 thin films grown at low temperature by pulsed laser deposition

We report on fully epitaxial FeSe0.5Te0.5 (FST) thin films of high quality grown on CaF2 (00l) substrate at a low temperature of 300 °C by pulsed laser deposition. The transport Jc of thin films is up to 1.36 MA cm−2 in self-field and 0.97 MA cm−2 in 9 T at 4.2 K, indicating very weak field dependence. A near isotropy of Jc (γ = as low as 1.09 at 9 T is achieved in the FST thin films. Moreover, there is no clear amorphous interfacial layer between the film and the substrate, probably due to low temperature and low laser repetition rate, while the thickness of the reaction layer is approximate 5 nm in many other works. The transmission electron microscopy evidence shows that some lattices with lateral size <5 nm × 20 nm seem to be disturbed. These location defects are thought to be responsible for the nearly isotropic behavior of the superconductivity.

Use of a non-volatile agent to stabilize severely incinerated dental remains.

The aim of this study was to identify volatile-free products that would be suitable for stabilizing incinerated dental remains at the scene of an incident, and that would not compromise any postmortem examination. The anterior mandibles of sheep were incinerated, sprayed unilaterally with stabilizing agents, vibrated for 30s, and assessed. The effect of the stabilizing solutions on radiographic examination was also recorded. Tests for volatility and the effect on human mandibles were also conducted. A flour/water mixture of one part flour to two parts water, and a paste mixture of one part Clag™ glue to one part water both produced significant stabilization results. The flour mixture left an opaque layer on the samples that it was applied to, which still allowed dental examination, but the glue paste mixture resulted in a clearer layer. Both solutions allowed radiographic examination and were free of volatiles. Diluted Clag™ paste, when sprayed on to incinerated remains, assists in their stabilization for transportation. When Clag™ paste is unavailable a mixture of two parts water to one part plain flour could be utilized for stabilization.

Searching for cold-adapted microorganisms in the underground glacier of Scarisoara Ice Cave, Romania

Scarisoara Ice Cave (Romania) hosts one of world’s largest and oldest underground glacier. While no studies were carried out on the existence of microorganisms in this cave’s ice block, our interest is to investigate the presence of microorganisms and their chronological distribution in the cave’s subterranean ice in relationship with past climatic changes. Samples were collected from ice layers of different age (from present to ~900 cal. yrs. BP), and the diversity of embedded microbial communities was assessed by classical cultivation and molecular techniques. The microorganisms from icesediments were cultivated at 4 °C and 15 °C, in the presence and absence of light. Epifluorescence microscopy analysis indicates the presence of autotrophic prokaryotes and eukaryotes in sunlightexposed ice and water samples. Total DNA was isolated from each ice sample and the bacterial and eukaryotic SSU-rRNA genes were amplified by PCR. The chemical composition and organic content of both deeply buried (>10 m inside the ice block) and surface (supra- glacial pond water) habitats were analyzed in relation to their age and organic composition. This study is the first to report on the presence of both prokaryotic and eukaryotic microorganisms in the subterranean ice block of Scarisoara Ice Cave, thriving in both organic-rich ice and clear ice layers. Phototrophic prokaryotes and eukaryotes were identified in sun-exposed recent ice. The composition of cold-adapted ice embedded microbiota varied with the habitat age and organic content, as resulting from dissimilarities in growth curve profiles at two different temperatures. The presence of bacteria and eukaryotes in all the analyzed samples was asserted by PCR amplification of SSU-rRNA gene fragments. These findings can be further used to reconstruct changes in the microbial diversity over the past approximately 5000 years, in correlation with climatic and environmental changes recorded by the ice block.

Surfactant Assisted Separation Spectrophotometric Procedure for the Trace Analysis of Copper (II) in Drug and Water Samples Using a Heterocyclic Pyridyl Azo Dye

4-(2-pyridyl-Azo) resorcinol mono sodium mono hydrate (NaPAR), a heterocyclic azo dye, was investigated for the flotation of copper (II). The metal ion forms a faint red complex with NaPAR in aqueous solution. An intense clear red layer was formed in the scum, after flotation, by adding an oleic acid (HOL) surfactant. The composition of the float is 1:2 (Cu(II): NaPAR). A highly selective and sensitive spectrophotometric procedure was proposed for the determination of micro-amounts of Cu(II) as its floated complex in the pH range 3.0-5.0. Beer’s law was obeyed up to 5x10-5 mol l-1. The Interferences from various foreign ions were avoided by adding excess NaPAR. The molar absorptivities of Cu-NaPAR and Cu-NaPAR-HOL systems are 5.3×104 and 6.1×105 mol-1cm-1 for the colored complexes in the aqueous and scum layers, respectively. The Cu-NaPAR complexes formed in aqueous solution and in the HOL were characterized by infrared spectral studies. The method was successfully applied to the analysis of Cu(II) in water and drug samples with a recovery >95% and a RSD <1.5%. The separation mechanism is explained.

Differentiating bubble-free layers from melt layers in ice cores using noble gases

AbstractMelt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method to detect melt events, based on the analysis of Kr/Ar and Xe/Ar ratios in ice cores, and apply it to the detection of melt in clathrate ice from the Eemian at NEEM, Greenland. Additionally, melt layers in ice cores can compromise the integrity of the gas record by dissolving soluble gases, or by altering gas transport in the firn, which affects the gas chronology. We find that the easily visible 1 mm thick bubble-free layers in the WAIS Divide ice core do not contain sufficient melt to alter the gas composition in the core, and do not cause artifacts or discontinuities in the gas chronology. The presence of these layers during winter, and the absence of anomalies in soluble gases, suggests that these layers can be formed by processes other than refreezing of meltwater. Consequently, the absence of bubbles in thin crusts is not in itself proof of a melt event.

Optical coherence tomography accurately identifies patients with penile (pre) malignant lesions: A single center prospective study.

Introduction:Currently, (multiple) biopsies are taken to obtain histopathological diagnosis of suspicious lesions of the penile skin. Optical coherence tomography (OCT) provides noninvasive in vivo images from which epidermal layer thickness and attenuation coefficient (μoct) can be quantified. We hypothesize that qualitative (image assessment) and quantitative (epidermal layer thickness and attenuation coefficient, μoct) analysis of penile skin with OCT is possible and may differentiate benign penile tissue from (pre) malignant penile tissue.Materials and Methods:Optical coherence tomography-imaging was performed prior to punch biopsy in 18 consecutive patients with a suspicious lesion at the outpatient clinic of the NKI-AVL. Qualitative analysis consisted of visual assessment of clear layers and a visible lower border of the lesions, quantitative analysis comprised of determination of the epidermal layer thickness and μoct. Results were grouped according to histopathology reports.Results:Qualitative analysis showed a statistically significant difference (P = 0.047) between benign and (pre) malignant lesions. Quantitative analysis showed that epidermal layer thickness and attenuation coefficient was significantly different between benign and (pre) malignant tissue, respectively, P = 0.001 and P < 0.001.Conclusion:In this preliminary study, qualitative and quantitative analysis of OCT-images of suspicious penile lesions shows differences between benign lesions and (pre) malignant lesions. These results encourage further research in a larger study population.

Ultrastructural Assessment of Granulomas in the Liver of Perch (Perca fluviatilis) Infected by Tapeworm

Granulomas caused by migration of larvae of a helminth parasite, Triaenophorus nodulosus, within the liver of perch (Perca fluviatilis) from Rimov Dam Lake (Czech Republic) were assessed by transmission electron microscopy. Lesions were found in the liver of 29 out of 34 perch examined (85.2%) and there were between 1 and 15 T. nodulosus larvae identified per host. Pathological changes were more severe in livers containing more granulomas. Within the granulomas, there were three concentric regions: an outer layer of fibrous connective tissue, a middle clear epithelioid layer and a central dark spindle cell layer. The outer layer contained mast cells, fibroblasts, thick collagen bundles and epithelioid cells. The granulomas contained few lymphocytes and macrophages. Hepatocytes adjacent to the granulomas showed pronounced degeneration (ranging from vacuolar degeneration to acute cellular swelling).

Complex deformation pattern of the Pamir–Hindu Kush region inferred from multi-scale double-difference earthquake relocations

The wide range of focal depths and the corresponding fault plane mechanisms in the Pamir–Hindu Kush region are believed to reflect the ongoing deformation along the Indian–Eurasian continental collision zone. Here we develop a multi-scale double-difference earthquake location algorithm to combine traveltime data recorded at local, regional and teleseismic distances. The 2906 relocated intermediate-depth earthquakes of MW≥4.5 we studied beneath the Hindu Kush show two groups of seismicity, with a separation of ca. 20–30km; these two groups exhibit thrust faults with different P-axes and different locations, reflecting the lateral geometry change of the seismic zone. Earthquakes beneath the Pamir present a clear south-dipping layer and unusual horizontal T-axes. There is a clear transition in direction of stress between the Hindu Kush and the Pamir regions. Here we focus on the complex deformation pattern beneath the continental collision zone arising from a combination of compression, tension, shearing and necking states.

Immunogold labeling shows that glycine-cysteine-rich beta-proteins are deposited in the Oberhäutchen layer of snake epidermis in preparation to shedding.

Shedding in snakes is cyclical and derives from the differentiation of an intraepidermal shedding complex made of two different layers, termed clear and Oberhäutchen that determine the separation between the outer from the inner epidermal generation that produces a molt. The present comparative immunocytochemical study on the epidermis and molts of different species of snakes shows that a glycine-cysteine-rich corneous beta-protein in a snake is prevalently accumulated in cells of the Oberhäutchen layer and decreases in those of the beta-layer. The protein is variably distributed in the mature beta-layer of species representing some snake families when the beta-layer merges with the Oberhäutchen but disappears in alpha-layers. Therefore, this protein represents an early marker of the transition between the outer and the inner epidermal generations in the epidermis of snakes in general. It is hypothesized that specific gene activation for glycine-cysteine-rich corneous beta-proteins occurs during the passage from the clear layer of the outer epidermal generation to the Oberhäutchen layer of the replacing inner epidermal generation. It is suggested that in the epidermis of most species glycine-cysteine-rich corneous beta-proteins form part of the dense corneous material that rapidly accumulates in the differentiating Oberhäutchen cells but decreases in the following beta-layer of the inner epidermal generation destined to be separated from the previous outer generation in the process of shedding. The regulation of the synthesis of these and other proteins is, therefore, crucial in timing the different stages of the shedding cycle in lepidosaurian reptiles.

Radiological assessment of bioengineered bone in a muscle flap for the reconstruction of critical-size mandibular defect.

This study presents a comprehensive radiographic evaluation of bone regeneration within a pedicled muscle flap for the reconstruction of critical size mandibular defect. The surgical defect (20 mm×15 mm) was created in the mandible of ten experimental rabbits. The masseter muscle was adapted to fill the surgical defect, a combination of calcium sulphate/hydroxyapatite cement (CERAMENT™ |SPINE SUPPORT), BMP-7 and rabbit mesenchymal stromal cells (rMSCs) was injected inside the muscle tissue. Radiographic assessment was carried out on the day of surgery and at 4, 8, and 12 weeks postoperatively. At 12 weeks, the animals were sacrificed and cone beam computerized tomography (CBCT) scanning and micro-computed tomography (µ-CT) were carried out. Clinically, a clear layer of bone tissue was identified closely adherent to the border of the surgical defect. Sporadic radio-opaque areas within the surgical defect were detected radiographically. In comparison with the opposite non operated control side, the estimated quantitative scoring of the radio-opacity was 46.6% ±15, the mean volume of the radio-opaque areas was 63.4% ±20. Areas of a bone density higher than that of the mandibular bone (+35% ±25%) were detected at the borders of the surgical defect. The micro-CT analysis revealed thinner trabeculae of the regenerated bone with a more condensed trabecular pattern than the surrounding native bone. These findings suggest a rapid deposition rate of the mineralised tissue and an active remodelling process of the newly regenerated bone within the muscle flap. The novel surgical model of this study has potential clinical application; the assessment of bone regeneration using the presented radiolographic protocol is descriptive and comprehensive. The findings of this research confirm the remarkable potential of local muscle flaps as local bioreactors to induce bone formation for reconstruction of maxillofacial bony defects.

Static and dynamic properties of argon inside carbon nanotubes

By using the molecular dynamics simulations, the static and dynamic properties of the argon inside the (10, 10), (20, 20) and (40, 40) carbon nanotubes (CNTs) are investigated. Here, the temperatures of 90 K and 298 K are considered to examine the temperature dependence of the concerned properties of the confined argon. The simulation results reveal that there are two clear atomic layers inside the (10, 10) CNTs at the two temperatures. As the diameter of the CNTs increases, the atomic layers become detectable only in the boundary region with the increase in temperature. For the dynamic property, the motion of the argon along the axial direction follows the conventional Fickian diffusion in the most cases, which is very slow in the case of close packing. In the radial direction, the subdiffusion and the Fickian diffusion can only be observed in the initial stage and then the mean squared displacements gradually approach the saturated values. The diffusion coefficients of the confined argon have a consistent tendency with those of the bulk argon after considering the actual reduced density.

Regulation of expression of p57KIP2 gene in extravillous trophoblast cells

Regulation of expression of p57KIP2 gene in extravillous trophoblast cells

Effects of Ultrasonic Impact Treatment on Performance of Armor Steel Welded Joints

In this paper, the armor steel welds were treated by ultrasonic impact equipment. The stress, hardness and cross section morphologies of the samples under different impact frequencies were measured by electrolytic polishing machines, X-ray stress analyzer and scanning electron microscopy (SEM). The results show that a clear grain refinement layer is formed on the surface of armored steel weld after ultrasonic impact treatment. Its hardness and residual stress all significantly improve. The ultrasonic impact treatment of different frequencies has greatly affect on ultrasonic impact effect, the higher the frequencies are, the better the ultrasonic impact effects are.

Analysis of solid concentration distribution in dense solid–liquid stirred tanks by electrical resistance tomography

The knowledge of the spatial solids distribution is important for predicting the performance of various processes carried out in mechanically stirred equipment. In this work, the solid suspension in a stirred tank equipped with PBT and Lightnin A310 impellers is investigated by electrical resistance tomography (ERT). The analysis concerns dense solid–liquid systems, with mass ratio of suspended solid to liquid up to 0.43, with the main goal of obtaining detailed information on the spatial distribution of the dispersed phase and on the mixing quality. The shape of the interface between the solid mixture and the clear liquid layer is also determined. The results provide insight into the complex behaviour of dense suspensions and can be adopted as a benchmark for advanced modeling techniques based on CFD methods.Based on the experimental results, a method for the evaluation of the distribution of the solids under different working conditions and geometrical set-up is suggested. This criterion can provide a guideline for scale-up, when equal solid distribution at different scales is required.

Particle Size Effect on the Corona Resistant Properties of PI/TiO&lt;sub&gt;2&lt;/sub&gt; Composite Films

Polyimide-based (PI) nanocomposites possess excellent electrical and thermal performance, widely used in inverter motor. In the paper using different particle sizes made polyimide/titania (PI/TiO2) nanocomposite films in situ polymerization, including 20nm A series and 50nm B series. The results shows that A series have a larger specific surface, combination of the film and matrix is closer without affecting the imidization of PI, and there is a clear interface layer and the structure is more stable. According to the time of corona-resistant A Series films is significantly longer than B Series films, especially the A series films with 15% of which corona-resistant time is 15h, five times than the pure PI. By both SAXS and XRD particle size in the matrix can be calculated, proving small particles can be better combination of the matrix of PI, increasing the number of traps, more effectively cutting off charge corrosion and making corona resistance greater performance.

Improving PDQ database search strategies to enhance investigative lead information for automotive paints

Modern automotive paints have a thin clear coat which on a microscopic fragment is often too thin to obtain accurate chemical information. The small size of the fragment also makes it difficult to accurately compare it with the manufacturer's paint color standards. Because adhesion between paint layers is usually very strong, both primer layers are often transferred during a collision if the clear coat and color coat layers are also transferred. Applying low level data fusion techniques where spectra from multiple sources (e.g., IR spectra of clear coat and primer paint layers) are combined and class membership information is extracted, search prefilters have been developed to determine the assembly plant of the vehicle from which an unknown paint sample originated. Even in challenging trials where the clear coat and undercoat layers evaluated were all from the same make (General Motors) within a limited production year range, the respective assembly plants of the vehicles could be identified using only chemical information. The development of search prefilters for the PDQ database to exploit multiple sources of IR data is needed to extract investigative lead information from clear coat and primer paint layer smears.

Topochemical Synthesis of Alkali-Metal Hydroxide Layers within Double- and Triple-Layered Perovskites

The formation of alkali-metal hydroxide layers within lamellar perovskites has been accomplished by a two-step topochemical reaction strategy. Reductive intercalation of ALaNb2O7 with alkali metal (A = K, Rb) and RbCa2Nb3O10 with Rb leads to A2LaNb2O7 and Rb2Ca2Nb3O10, respectively. Oxidative intercalation with stoichiometric amounts of water vapor, produced by the decomposition of calcium oxalate monohydrate in a sealed ampule, allows the insertion hydroxide species. Compounds of the form (A2OH)LaNb2O7 (A = K, Rb) and (Rb2OH)Ca2Nb3O10 are accessible. X-ray diffraction data indicates a clear layer expansion of almost 3 Å on the insertion of hydroxide relative to that of the parent. Rietveld refinement of neutron diffraction data collected on deuterated samples of (Rb2OD)LaNb2O7 (P4/mmm space group, a = 3.9348(1) Å, c = 14.7950(7) Å) finds that both rubidium and oxygen species reside in cubic sites forming a CsCl-like interlayer structure between niobate perovskite blocks. Hydrogens, attached to the interlayer oxygens, are disordered over a 4-fold site in the x-y plane and have O-H bond distances (0.98 Å) consistent with known hydroxide species. This synthetic approach expands the library of available topochemical reactions, providing a facile method for the construction of alkali-metal hydroxide layers within receptive perovskite hosts.

Effect of blood in the cerebrospinal fluid on the accuracy of cerebral oxygenation measured by near infrared spectroscopy.

Near infrared spectroscopy (NIRS) is an optical technique used to examine the oxygenation state of tissues such as the brain in patients, including those with brain injury. We have examined the effect of a cerebrospinal fluid (CSF) contaminant, specifically haemoglobin, on the sensitivity of cerebral NIRS signals through computer simulation. Previous models of light transport in the head have shown that the clear CSF layer has a profound effect on the sensitivity profile of the NIRS signal due to its low absorbing, low scattering qualities. In subarachnoid haemorrhage, which may accompany brain injury, the principal near infrared chromophore, haemoglobin, is released into the CSF. Sensitivity was measured through forward modeling and the presence of haemoglobin within the CSF was modeled by increasing the absorption coefficient of the layer, with sensitivity quantified in terms of the partial pathlength of light within the brain. The model demonstrated that increases in the CSF absorption led to a marked decrease in the sensitivity to changes in the brain layer. This suggests that blood or other contaminants in the CSF may have a significant effect on the utility of NIRS for measurement of cerebral oxygenation, and merits further investigation.

Location of cation impurities in NGRIP deep ice revealed by cryo-cell UV-laser-ablation ICPMS

AbstractIn polar ice sheets, the average grain size varies with depth. Ice grain size increases due to several factors including ice temperature and impurity content, which in turn varies with climate. The effect of impurities on grain growth is thought to be crucial but has never been observed experimentally. Using a methodology recently developed at Royal Holloway University of London, in situ chemical analysis of frozen ice at sub-ppm concentrations with unprecedented spatial resolution (~150 μm) is achievable using ultraviolet laser ablation inductively coupled plasma mass spectrometry (UV-LA-ICPMS) featuring a two-volume cryo-LA-cell. Following surface cleaning with a custom-built vice equipped with a ceramic blade, NGRIP ice slabs (~86 ka before AD 2000) have been analysed using a series of one-dimensional profiles and two-dimensional maps of laser spots at a resolution of 200–300 μm. Results demonstrate that cation impurities are not uniformly distributed in ice layers and show significant variations in concentration on a sub-millimetre scale. Furthermore, a different pattern of elemental distribution between clear ice and layers enriched in impurities (cloudy bands) has been identified: while concentration differences for cloudy bands are not resolvable between boundaries and inner grain domains, within clear ice, grain boundaries and junctions are significantly (up to 100 times) impurity-enriched relative to corresponding grain interiors.