In this work, the mechanical properties of the metal active gas (MAG) weld zone and heat affected zone (HAZ) were characterized utilizing the continuous indentation method together with its finite ...element (FEM) analysis. To verify the measured properties, uni-axial tension and three point bending tests were performed for DP590 welded specimens. For numerical simulations, the isotropic hardening law was assumed along with the non-quadratic anisotropic yield function, Yld2000-2d. As for the failure criterion of the base material and weld zones particularly for the failure evaluation in the uni-axial tension test, Hill’s bifurcation theory and the
M–
K theory were applied to calculate the forming limit diagrams considering all measured properties including strain-rate sensitivity.
In this study, S235JR structural steel samples in uncoated condition and coated (shop-primer) in different thicknesses were welded by MAG (Metal Active Gas) welding method, and the effects of these ...applications on the mechanical and microstructure properties of the material were investigated. In the experimental studies, the first specimen group were used without any sandblasting and coating application, the second group specimens were sandblasted at Sa 2 ½ degree, and 25 µm, 50 µm, and 75 µm coatings were applied to the specimens in the other group. Surface conditions and coating thicknesses were selected as the variable parameters. With the examination of the radiography films, it was observed that the surface conditions affected the welded joint. As a result of the study, it was observed that altered coating thicknesses caused defects in the welding zone. It was determined that the coating thickness partially affected the mechanical properties, and the highest hardness values occurred in the weld zone in all samples. Relatively low values were obtained in tensile, bending and Charpy impact tests performed on sample groups with 75 µm coating thickness. The results were verified by the surface fracture, SEM, and EDS studies.
El uso de “Dr.(c)” y de “Mag.(c)” en las presentaciones públicas de estudiantes de posgrado ha aumentado notablemente en Chile. Este artículo presenta dos estudios para determinar la magnitud de esta ...situación en sitios web universitarios y la confusión que este tipo de presentación podría acarrear en el público. El primer estudio recolectó las presentaciones de 915 profesores universitarios contenidas en los sitios web oficiales de 47 universidades. Los resultados indicaron que alrededor de un 18% de los profesores universitarios estaban haciendo un posgrado y que usan el Dr.(c) y el Mag.(c) como presentación a pesar de que es dudoso que se encuentren en la última etapa de sus programas, que sería la candidatura. El segundo estudio encuestó a 119 estudiantes universitarios buscando la comprensión que tenían del sufijo Dr.(c). Los resultados indicaron que alrededor de un tercio de la muestra interpretó el Dr.(c) como una credencial equivalente a Dr., lo que apoya la idea de que este tipo de presentación se presta para engaño y confusión.
Anti-Myelin Associated Glycoprotein (anti-MAG) neurological involvement classically manifests as a peripheral neuropathy with prominent sensitive symptoms. We describe a case report of a patient with ...positive anti-MAG antibodies presenting with clinical and neurophysiological evidence of spinal cord impairment. A 69-year-old woman came to our attention with subacute onset of dysesthesias at lower limbs and ataxia. Blood routine tests and hematological work-up led to a diagnosis of monoclonal gammopathy of undetermined significance. High titers of anti-MAG antibodies was revealed (34,594.70 BTU/ml, normal range 0-1000). Nerve conduction studies (NCS) ruled out a polyneuropathy at lower limbs. Somatosensory evoked potentials (SSEPs) showed prolonged central conduction time (CTT) at lower limbs, suggesting a dorsal column damage. Brain and spinal cord Magnetic Resonance Imaging (MRI) did not reveal any significant lesion. Analysis of cerebrospinal fluid (CSF) evidenced an albumin-cytologic dissociation. She was treated with corticosteroids with temporary remission of sensory symptoms and normalization of CTT. Subsequently, she developed a multineuropathy which was successfully treated with Rituximab. We discuss the potential role of anti-MAG antibodies in the pathophysiology of dorsal column impairment and the clinical usefulness of SSEPs in monitoring the evolution of anti-MAG neuropathy.
The main aim of this work was to evaluate the influence and optimize the factors of the TIG-MIG/MAG hybrid welding process on the geometry of the weld bead. An experimental design using the Taguchi ...methodology (robust design method) was used to conduct the experiments. The experiments were carried out according to an orthogonal matrix with 27 experiments, with three replicates each, totaling 81 test specimens. The factors (MIG/MAG shielding gas type, MIG/MAG voltage, MIG/MAG wire feed, gas flow rate of TIG, electric current intensity of TIG and welding speed) were varied with three levels each. Penetration, heat-affected zone (HAZ), bead width and bead height were the response variables analyzed. The results showed that the penetration was significantly influenced by the MIG/MAG wire feed, MIG/MAG shielding gas type, MIG/MAG voltage and welding speed. The HAZ has been influenced by MIG/MAG voltage, MIG/MAG shielding gas type, welding speed and electric current intensity of TIG. All factors had effects on the width, except the MIG/MAG wire feed. The bead height was significantly influenced by the MIG/MAG wire feed and by the electric current intensity of TIG. Optimizing the process was performed, so that for each output variable, the values of the factors that should be used were indicated, and the optimization was confirmed by welding test specimens.
In this paper, with constant welding parameters, the droplet transfers at different positions have been studied by high speed video during CO
2
laser–MAG hybrid welding of E36 steel. The results ...indicated that the impact location of droplet was mainly affected by the electromagnetic force and gravity. At flat position, the droplet impacted into the weld pool near the keyhole. While at horizontal position, the impact locations of the droplet could be divided into three types: drop down, impact under the seam and impact into the weld pool. For vertical position, the large droplet impacted on the hump of weld pool. The results also showed that the droplet frequency depended on its growing speed and diameter. At flat, horizontal and vertical positions the mean droplet diameters were 2.2, 2.0 and 3.1 mm and the mean transfer frequencies were 27.0, 44.2 and 10.7 Hz, respectively. Furthermore, the optimisation of welding process has also been investigated.
Magnesium–aluminium spinel has been synthesized by citrate–nitrate route using hydrated nitrates of Mg and Al as the precursors with a citrate–nitrate ratio of 1:1. Self-ignition of the gel-like mass ...yielded a black mass, which crystallized to Mag–Al spinel on calcination at 650 °C for 9 h. The crystallized mass was a mixture of ordered and disordered phases of Mag–Al spinel. Phase pure-ordered spinel could be obtained for powders calcined at 1100 °C and above. The green compacts of the spinel powders could be sintered to near theoretical density at 1150 °C for 30 min. The activation energy for densification was calculated (16.4 kcal/mol) assuming Arrhenius type behaviour. The densification mechanism could be assigned to the ordering of the disordered spinel involving vacancy diffusion through the surface.
Complementary interacting molecules on myelin and axons are required for long-term axon–myelin stability. Their disruption results in axon degeneration, contributing to the pathogenesis of ...demyelinating diseases. Myelin-associated glycoprotein (MAG), a minor constituent of central and peripheral nervous system myelin, is a member of the Siglec family of sialic acid-binding lectins and binds to gangliosides GD1a and GT1b, prominent molecules on the axon surface. Mice lacking the ganglioside biosynthetic gene
Galgt1 fail to express complex gangliosides, including GD1a and GT1b. In the current studies, CNS and PNS histopathology and behavior of
Mag-null,
Galgt1-null, and double-null mice were compared on the same mouse strain background. When back-crossed to >99% C57BL/6 strain purity,
Mag-null mice demonstrated marked CNS, as well as PNS, axon degeneration, in contrast to prior findings using mice of mixed strain background. On the same background,
Mag- and
Galgt1-null mice exhibited quantitatively and qualitatively similar CNS and PNS axon degeneration and nearly identical decreases in axon diameter and neurofilament spacing. Double-null mice had qualitatively similar changes. Consistent with these findings,
Mag- and
Galgt1-null mice had similar motor behavioral deficits, with double-null mice only modestly more impaired. Despite their motor deficits,
Mag- and
Galgt1-null mice demonstrated hyperactivity, with spontaneous locomotor activity significantly above that of wild type mice. These data demonstrate that MAG and complex gangliosides contribute to axon stability in both the CNS and PNS. Similar neuropathological and behavioral deficits in
Galgt1-,
Mag-, and double-null mice support the hypothesis that MAG binding to gangliosides contributes to long-term axon–myelin stability.
The objective of the EuCARD2 WP10 (Future Magnets) research activity is to demonstrate high-temperature superconducting magnet technology for accelerator applications by building a short demonstrator ...dipole with an aperture of 40 mm, operating field of 5 T, and understood field quality. One of the magnet requirements is of small inductance, for use in long magnet strings; hence, the superconducting cable must have large current-carrying capacity, in the range of 10 kA at the operating conditions of 4.2 K and 5 T. An initial down-selection of the cable material and geometry resulted in the choice of REBCO tapes assembled in a Roebel cable as the baseline layout. In this paper, we described the requirements derived from magnet design, the selection process that led to the choice of material and geometry, the reference design of the cable, and its options. Activities have started to address fundamental issues, such as tape performance and tape processing through the cable construction, and key performance parameters such as cable critical current under stress or magnetization. Here, we report the main highlights from this work.
Amygdalin is a natural cyanogenic compound that plants produce in the fight against insects and herbivores. Excessive amounts of amygdalin by animals and humans can potentially lead to fatal ...intoxication. However, studies confirm that amygdalin has antitumor properties, including the ability to inhibit the proliferation of cancer cells and to induce their apoptosis. The analysis of amygdalin in various matrices is an important analytical problem today. The publication presents the methodology of direct determination of amygdalin in water, sewage, and biological materials using electrospray ionization mass spectrometry (ESI-MS) and a new analytical method using flowing atmospheric-pressure afterglow mass spectrometry (FAPA-MS). The methods of analyte pre-concentration using a magnetic, molecularly imprinted polymer (mag-MIP) and the influence of interferents on the recorded spectra were discussed. Analytical parameters in ESI-MS and FAPA-MS methods were established. The linearity range was 4.5 µg L
-45 mg L
in positive mode ESI-MS and FAPA-MS. The limit of detection (LOD) for ESI-MS was 0.101 ± 0.003 µg L
and the limit of quantification (LOQ) was 0.303 ± 0.009 µg L
. In FAPA-MS, the LOD was 0.050 ± 0.002 µg L
and the LOQ was 0.150 ± 0.006 µg L
. The content of amygdalin in various matrices was determined.
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