Calibration approach to electron probe microanalysis: A study with PWA-1480, a nickel base superalloy

The utility of an indirect calibration approach in electron probe microanalysis is explored. The methodology developed is based on establishing a functional relationship between the uncorrected k-ratios and the corresponding concentrations obtained using one of the ZAF correction schemes, for all the desired elements in the concentration range of interest. In cases where a very large number of analyses are desired, such a technique significantly reduces the total time required for the microprobe analysis without any significant loss of precision in the data. A typical application of the method in the concentration mapping of the transverse cross-section of a dendrite in directionally solidified PWA-1480, a nickel-based superalloy, is described

Secondary arm coarsening and microsegregation in superalloy PWA-1480 single crystals: Effect of low gravity

Single crystal specimens of nickel base superalloy PWA-1480 were directionally solidified on ground and during low gravity (20 sec) and high gravity (90 sec) parabolic maneuver of KC-135 aircraft. Thermal profiles were measured during solidification by two in-situ thermocouples positioned along the sample length. The samples were quenched during either high or low gravity cycles so as to freeze the structures of the mushy zone developing under different gravity levels. Microsegregation was measured by examining the solutal profiles on several transverse cross-sections across primary dendrites along their length in the quenched mushy zone. Effect of gravity level on secondary arm coarsening kinetics and microsegregation have been investigated. The results indicate that there is no appreciable difference in the microsegregation and coarsening kinetics behavior in the specimens grown under high or low gravity. This suggests that short duration changes in gravity/levels (0.02 to 1.7 g) do not influence convection in the interdendritic region. Examination of the role of natural convection, in the melt near the primary dendrite tips, on secondary arm spacings requires low gravity periods longer than presently available on KC-135. Secondary arm coarsening kinetics show a reasonable fit with the predictions from a simple analytical model proposed by Kirkwood for a binary alloy

Comparative Study of Changes in Pharyngeal Airway Dimension and Hyoid Bone Position following Nonsurgical Orthodontic Treatment in Class I and Class II Subjects.

BACKGROUND: Pharyngeal airway dimensions, narrowing of pharyngeal passage and hyoid bone positions are of interest in orthodontics .It is evident that there exists a mutual correlation between position of the hyoid bone, volume of pharyngeal airway and dentofacial structures. Therefore it is relevant to evaluate the changes in nasopharyngeal airway and hyoid bone position in subjects with moderate dentofacial deformities, who had orthodontic treatment. This retrospective, analytical cephalometric study had been undertaken to investigate correlation in skeletal Class I and skeletal Class II subjects who had undergone non-surgical orthodontic treatment. AIM: The aim of this study was to evaluate and compare the changes in pharyngeal airway dimension and hyoid bone position following non-surgical orthodontic treatment in Class I and Class II dentofacial deformities. MATERIALS AND METHODS: 40 sets (pre & post treatment ) of lateral cephalograms of subjects (20 skeletal Class I & 20 skeletal Class II malocclusion) were analysed. The control group consisting of 20 lateral cephalograms of subjects with normal occlusion and good visibility of hyoid bone were used .All cephalograms were taken in natural head position, with PLANMECA PM 2002 CC PROLINE machine. All the radiographs were scanned with CANON D520 MF scanner and digitized. A Cephalometric analysis software AX CEPH version 2.3.0.74 was used to analyse the radiographs. RESULTS: Pretreatment hypopharynx area was significantly constricted in both Class I and Class II groups with highly significant reduction (p value < 0.001) in Class II groups in comparison with normoocclusion group. In Class I malocclusion group there was a significant decrease in overall upper airway dimensions, with more reduction in glossopharynx and hypopharynx areas following orthodontic treatment with only velopharynx and glossopharynx areas approximating to the values of the normoocclusion group. In Class II malocclusion the glossopharynx and hypopharynx areas were widened significantly, still the hypopharynx area was not widened to the level of normoocclusion group. After treatment the hyoid was retracted postero inferiorly in Class I group and in Class II group the hyoid bone was shifted anterosuperiorly. Still the hyoid position was not approximated to that of normoocclusion group. There was no statistically significant (p value > 0.05) sexual dimorphism in both pharyngeal airway dimensions and hyoid bone positions in all three groups. CONCLUSION: There is a definite difference in pharyngeal airway dimension and hyoid bone position in different malocclusions. It was evident that Non-surgical orthodontic treatment had a significant influence on the pharyngeal airway dimensions and hyoid bone positions in Class I and Class II malocclusion corrections

An Efficient Score level Multimodal Biometric System using ECG and Fingerprint

Biometric system is a security system that uses human’s unique traits to identify and authenticate the user. Biometrics refers to biological traits of a human that are often categorized as physiological traits like fingerprint, iris, face and behavioral characteristics like signature style, voice and typing rhythm. The Biological signals like Electrocardiography (ECG), Electromyography(EMG), and Electroencephalography (EEG) have not been explored to biometric applications as their scope was limited to medical applications only. Recent survey suggests that these biological signals can be explored as a part of the biometric application. The main objective of this paper is to explore the possibility of using the ECG as a part of multimodal biometric. ECG has lower accuracy but fusing it with a traditional biometric like fingerprint yields a higher accuracy rate and it is really difficult to spoof the system. The proposed multimodal biometrics system has an accuracy of 98% with the false acceptance rate of 2% and almost 0% of false rejection rate

1,1′-[4-(4-Methoxy­phen­yl)-2,6-dimethyl-1,4-dihydro­pyridine-3,5-di­yl]diethanone

In the title compound, C18H21NO3, which belongs to the family of calcium channel blockers, the dihydropyridine ring assumes a flattened boat conformation. The two carbonyl units adopt a synperiplanar conformation with respect to the double bonds in the dihydro­pyridine ring. The methoxy­phenyl ring is almost perpendicular to the prydine ring [dihedral angle = 89.01 (7)°]. In the crystal, the mol­ecules are connected by inter­molecular N—H⋯O hydrogen bonds

Dendrite Spacings in Directionally Solidified Superalloy PWA-1480

Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys

Solutal Partition Coefficients in Nickel-Based Superalloy PWA-1480

Solutal profiles in dendritic single-crystal specimens of PWA-1480 nickel-base superalloy, which were directionally solidified and quenched, were examined on several transverse cross-sections to obtain the partition coefficients. Similar to their nickel-base binaries, the partition coefficients of tantalum, titanium, and aluminum were found to be less than unity; those of tungsten and cobalt were greater than unity. The partition coefficients were temperature independent in the range 1584-1608 K. The contribution of solid-state diffusion to microsegregation was observed to be negligible

Methyl 4-(3-eth­oxy-4-hydroxy­phen­yl)-6-methyl-2-oxo-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate monohydrate

In the title compound, C15H18N2O5·H2O, the pyrimidine ring adopts a flattened-boat conformation. The eth­oxy group attached to the benzene ring is in an extended conformation. The oxopyrimidine mol­ecules are linked into centrosymmetric R 2 2(20) dimers by O—H⋯O hydrogen bonds. The dimers are linked by N—H⋯O hydrogen bonds, forming a two-dimensional network parallel to the bc plane. Adjacent networks are cross-linked via N—H⋯O and O—H⋯O hydrogen bonds involving the water mol­ecules

Magnetic and Low Temperature Conductivity Studies in Oxidized Nano Ni Films

A set of single layered nanostructured Ni films of thickness, t = 25 nm, 50 nm, 75 nm and 100 nm have been deposited using electron beam gun evaporation technique at 473 K under high vacuum condition. From the grazing incidence X-ray diffraction (GIXRD) studies, NiO phase formation has been noted. Grain sizes of the films were determined. The microstructure was examined by scanning electron microscope (SEM) studies. Average surface roughness was determined by atomic force microscope (AFM). The room temperature magnetization has been measured using the vibrating sample magnetometer (VSM). The coercive field was observed to be increasing with increasing t and became maximum for t = 75 nm and decreases for further increase in t. The behavior of coercive field with t indicated softness of the films. Low temperature electrical conductivity in the range from 5 K to 300 K has been measured. Temperature dependence of electrical conductivity showed semiconducting behavior. At temperatures above θD/2 (θD is the Debye temperature), the conductivity behavior has been understood in the light of Mott’s small polaron hopping model and activation energies were determined. An attempt has been made to understand conductivity variation below θD/2 using variable range hopping models due to Mott and Greaves. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2371

Sodium-activated potassium channels shape peripheral auditory function and activity of the primary auditory neurons in mice

Potassium (K+) channels shape the response properties of neurons. Although enormous progress has been made to characterize K+ channels in the primary auditory neurons, the molecular identities of many of these channels and their contributions to hearing in vivo remain unknown. Using a combination of RNA sequencing and single molecule fluorescent in situ hybridization, we localized expression of transcripts encoding the sodium-activated potassium channels K(Na)1.1(SLO2.2/Slack) and K(Na)1.2 (SLO2.1/Slick) to the primary auditory neurons (spiral ganglion neurons, SGNs). To examine the contribution of these channels to function of the SGNs in vivo, we measured auditory brainstem responses in K(Na)1.1/1.2 double knockout (DKO) mice. Although auditory brainstem response (wave I) thresholds were not altered, the amplitudes of suprathreshold responses were reduced in DKO mice. This reduction in amplitude occurred despite normal numbers and molecular architecture of the SGNs and their synapses with the inner hair cells. Patch clamp electrophysiology of SGNs isolated from DKO mice displayed altered membrane properties, including reduced action potential thresholds and amplitudes. These findings show that K(Na)1 channel activity is essential for normal cochlear function and suggest that early forms of hearing loss may result from physiological changes in the activity of the primary auditory neurons