3,561 research outputs found
Higgsino Dark Matter in a SUGRA Model with Nonuniversal Gaugino Masses
We study a specific SUGRA model with nonuniversal gaugino masses as an
alternative to the minimal SUGRA model in the context of supersymmetric dark
matter. The lightest supersymmetric particle in this model comes out to be a
Higgsino dominated instead of a bino dominated lightest neutralino. The thermal
relic density of this Higgsino dark matter is somewhat lower than the
cosmologically favoured range, which means it may be only a subdominant
component of the cold dark matter. Nonetheless, it predicts favourable rates of
indirect detection, which can be seen in square-km size neutrino telescopes.Comment: Version to appear in Phys. Rev. D. A few references added in the
bibliography and a comment added in Section 2. LaTex, 16 pages, 4 figure
Subsurface deformation during Vickers indentation of bulk metallic glasses
Bonded interface technique was employed to examine the nature of subsurface deformation during Vickers indentation in two kinds of bulk metallic glasses (BMGs), Pd42.1Ni39.77P18.13, and Zr56.69Cu26.96Al10.95Ni5.4. Quantitative information such as the shear band spacing, pile-up length, subsurface deformation zone size etc. was recorded for indentation loads ranging from 50 to 5000 g. Experimental results show that both the BMGs have an average hardness value of ~550 VHN with slightly higher hardness at low loads. Observations of deformation zones indicate that they deform appreciably through the shear band mechanism. For both bulk indentation, as well as the interface indentation, the normalized size of the deformation zone was found to be independent of the applied load. Two types of shear bands, radial, and semi-circular in nature, have been observed. These results are compared with similar studies made on ductile metals and silicate glasses
Hardness and plastic deformation in a bulk metallic glass
An experimental investigation into the Vickers hardness and associated plastic deformation in as-cast and annealed Pd42Ni40P18 bulk metallic glass was conducted. In addition to the bulk indentation behavior, the deformation morphology underneath the indenter and its variation with annealing time was examined by employing the bonded interface technique. For both the bulk and the interface indentations, the trends in the shear band induced plastic deformation zone sizes with the indentation load agree well with those predicted from the expanding cavity model. However, the yield strength extracted from the indentation data is higher than that measured in uniaxial compression, indicating pressure sensitive plasticity. Results show that the as-cast as well as the partially crystallized alloys deform appreciably through the shear band mechanism, with semi-circular and radial shear band morphologies. The latter gets increasingly prominent with increasing annealing time. Atomic force microscopy of the deformation region reveals increasing shear band heights with load, consistent with nanoindentation results. Whereas the spacing between semicircular shear bands was found to be independent of their distance from the tip of the indenter for the as-cast alloy, it was found to increase linearly, after a small zone of constant spacing, in the annealed alloys. Implications of this study in understanding the mechanical behavior of metallic glasses and their derivatives are discussed
Recycling and Treatment of Settling Pond Fines - A challenge to Industry and Environment
About 3.0 Million tonness of coking coal fines (-0.5mm) generated from various coal preparation plants are lying in the lagoons/settling ponds in the vicinity of these plants for quite some time . In addition, 60,0001t of slurries are being bled every month to these waste basins. These discarded coal fines which contain significant amount of vitrinite enriched coking materials, are not being properly utilised due to the following reasons.
(i)Inability of existing coal washing circuit to benef-
iciate these coal fines from the slurry economically
ii) Environmental restrictions regarding waste disposal
were not stringent; (iii) Non-availability of suit-
able technology to recover the coal fines at
desired quality.
To use these coal slurry fines, CFRI through decades long R&D efforts have developed an improved process technology, which can recover finest cleans (ash < 15%) from the said high ash (30-35%) coal slurry. Based on CFRI to Tech-nology, three mini flotation plants have been commissioned of throughput capacity 5 to 10 tph in small scale sector, which are successfully producing cleans (Yield 50-60%, and Moisture < 20%) from high ash coal slurry and dispatching the low ash cleans to M/s IISCO. Burnpur as one of their coking blend constituents for metallurgical coke making. Many irety mini flotation plants are coming into picture based upon this technology. This paper summarises data, concerning slurry pond quality estimate, floatability, material recovery, etc
Deformation morphology underneath the vickers indent in a Zr-based bulk metallic glass
Hardness and plastic deformation during Vickers indentation in as-cast, annealed, and fully crystallized Zr57Cu27Al11Ni5 bulk metallic glass was examined. Subsurface deformation morphology under the indenter tip was studied at various loads and for different annealing time. Appreciable plastic deformation, through shear banding, occurs in the as-cast and annealed alloys. Two different types of shear bands are observed. Their occurrence depends upon the amount of annealing and hence on the extent of crystallization. The fully crystallized alloy exhibits extensive cracking. Trends in the deformation zone size with load are consistent with the expanding cavity model, while the shear band morphology, particularly for the as-cast sample, attests the qualitative applicability of the slip line field theory
Estimates of genetic parameters of fruit quality traits in teasle gourd (Momordica subangulata Blume. subsp. renigera)
The present investigation was carried out to assess genetic variability, heritability and genetic advance in five genotypes of teasle gourd. The experiment was laid out in a randomized block design with four replications. High phenotypic coefficients of variation were observed for all characters except ascorbic acid in excoarp, ascorbic acid in mesocarp, total soluble solids (TSS) in exocarp, b-carotene in exocarp, acidity in mesocarp, b-carotene in mesocarp, TSS in mesocarp, acidity in exocarp which showed high heritability coupled with high genetic advance indicating that these traits were gene control and simple phenotypic selection can be used for further improvement of these traits. Fruit weight, which showed the highest positive direct effect on fruit yield also showed positive correlation with β-carotene in exocarp. The most important fruit quality influencing traits from the study includes TSS content of exocarp and mesocarp since these traits character showed positive correlations with most important fruit quality characters.Keywords: Teasle gourd, clones, variability, heritability, genetic advance, correlation coefficientAfrican Journal of Biotechnology, Vol. 13(2), pp. 257-264, 8 January, 201
WMAP Data and Recent Developments in Supersymmetric Dark Matter
A brief review is given of the recent developments in the analyses of
supersymmetric dark matter. Chief among these is the very accurate
determination of the amount of cold dark matter in the universe from analyses
using WMAP data. The implications of this data for the mSUGRA parameter space
are analyzed. It is shown that the data admits solutions on the hyperbolic
branch (HB) of the radiative breaking of the electroweak symmetry. A part of
the hyperbolic branch lies in the so called inversion region where the LSP
neutralino becomes essentially a pure Higgsino and degenerate with
the next to the lightest neutralino and the light chargino
. Thus some of the conventional signals for the observation of
supersymmetry at colliders (e.g., the missing energy signals) do not operate in
this region. On the other hand the inversion region contains a high degree of
degeneracy of , , leading to coannihilations
which allow for the satisfaction of the WMAP relic density constraints deep on
the hyperbolic branch. Further, an analysis of the neutralino-proton cross
sections in this region reveals that this region can still be accessible to
dark matter experiments in the future. Constraints from and from
are discussed. Future prospects are also discussed.Comment: 15 pages Latex. Invited talk at the IV International Conference on
Non-accelerator New Physics (NANP'03), Dubna, Russia, June 23-28, 200
Isocyanurate transformation induced healing of isocyanurate–oxazolidone polymers
Isocyanurate–oxazolidone (ISOX) polymers have been reported as a novel, intrinsically self‐healable thermoset, and their healing mechanism under the effect of nucleophiles, such as tertiary amines and pyridines during polymerization, is thoroughly investigated in this study. This work provides evidence that the healing behavior of the polymers results part from the transformation of isocyanurate to oxazolidone on the fracture surfaces of the ISOX polymers at elevated temperatures. The isocyanurate transformation is characterized by chemical composition of the ISOX polymers before and after a predetermined healing procedure, through a combination characterization of Fourier transform infrared spectroscopy and carbon nuclear magnetic resonance spectroscopy. From the chemical composition of the ISOX polymers, an increased oxazolidone fraction is observed after the healing event, which verifies the hypothesized healing mechanism. By correlating the change in oxazolidone fraction in the polymers during the healing event, with the corresponding healing performance of the polymers, healing efficiencies of the polymers are shown to be inversely proportional to the ratio of oxazolidone to isocyanurate in the polymers. The transformation to oxazolidone is also shown to be dependent on two variables, nucleophilicity of the polymerization catalyst and duration of the postcure. The isocyanate and epoxide polymerization mechanism in the presence of nucleophiles is also investigated to explain the effect of the catalyst nucleophilicity on the chemical composition as well as the healing performance of the ISOX polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48698.Isocyanurate‐to‐oxazolidone transformation within the polymers for healing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/1/app48695-sup-0001-FigureS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/2/app48698_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154270/3/app48698.pd
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