16,602 research outputs found
Nanofiller Fibre-Reinforced Polymer Nanocomposites
In this work, the technology of nano and micro-scale particle reinforcement
concerning various polymeric fibre-reinforced systems including polyamides (PA),
polyesters, polyurethanes, polypropylenes and high performance/temperature
engineering polymers such as polyimide (PI), poly(ether ether ketone) (PEEK),
polyarylacetylene (PAA) and poly p-phenylene benzobisoxazole (PBO) is reviewed.
When the diameters of polymer fibre materials are shrunk from micrometers to
submicrons or nanometers, there appear several unique characteristics such as
very large surface area to volume ratio (this ratio for a nanofibre can be as
large as 103 times of that of a microfibre), flexibility in surface
functionalities and superior mechanical performance (such as stiffness and
tensile strength) compared with any other known form of the material. However,
nanoparticle reinforcement of fibre reinforced composites has been shown to be a
possibility, but much work remains to be performed in order to understand how
nanoreinforcement results in dramatic changes in material properties. The
understanding of these phenomena will facilitate their extension to the
reinforcement of more complicated anisotropic structures and advanced polymeric
composite systems
Preparation, Characterization and NO-CO Redox Reaction Studies over Palladium and Rhodium Oxides Supported on Manganese Dioxide
The catalytic activity of PdO/MnO2 and Rh2O3/MnO2 is investigated for NO-CO redox reaction. Supported catalysts are prepared by wet impregnation method. Among the tested catalysts, PdO/MnO2 shows higher activity for this reaction. Active metal dispersion on MnO2 enhances the selectivity for N2 over N2O in this reaction. The XRD substantiate the formation of MnO2 monophasic phase. SEM images show the formation of elongated particles. TEM images indicate nano-size rod-like morphologies. An increase in the catalytic activity is observed on supported Pd and Rh oxides on MnO2. Temperature programed desorption studies with NO and CO are undertaken to investigate the catalytic surface studies. © 2015 BCREC UNDIP. All rights reserve
Life Extension of Aircraft Components - An IAF Perspective
Due to escalating cost of aircraft and feasibility for upgrading existing fleet with advance technology insertions at comparatively lesser cost, a trend is
observed world over to extend the life of aircraft. IAF is no exception to this.Since OEMs have started demanding exhorbitant fees for giving life extension technology of their aircraft, a number of life extension projects have been undertaken by IAF with the help of various R&D, Public Sector, academic,certification and inspection agencies. These studies have highlighted the need to carry out basic and applied research for life extension of various aircraft components like airframe structures, aeroengine, undercarriage, canopies /perspex and rotables. A core group formed at the instance of IAF has
identified these proposals under a project code named `Project LIFEX'. It is the perception of IAF that adequate expertise is available within the country to meet all her life extension requirements
Harmonious Healing: A Review of Music Therapy, a Humanities-Based Approach to Alzheimer’s Disease Treatment
Alzheimer’s Disease (AD) is a progressive neurodegenerative disease often characterized by memory loss, confusion, and overall cognitive decline. The aging global population has, in recent years, highlighted the fundamental lack of pharmacological treatments for individuals facing an AD diagnosis. In response, a growing body of research has shifted focus to non-pharmacological humanities-based interventions. One such intervention has been music therapy (MT). Music-focused measures have shown great promise as a method of slowing cognitive decline, but mixed results in the literature warrant the need for further investigation. Often, socioeconomic barriers can limit an individual’s access to drug-related treatments, but the affordable and straightforward nature of music therapy circumvents these issues and further establishes the prospect for widespread use. In particular, these measures have been shown to rescue episodic and semantic memory, and due to their non-invasive nature, can be utilized as a proactive treatment strategy for young individuals at a higher risk for cognitive decline. This review aims to showcase the efficacy of music therapy as a novel humanities-based approach to AD management and indirect mechanism for improving emotional well-being
Two Dimensional Clustering of Gamma-Ray Bursts using durations and hardness
Gamma-Ray Bursts (GRBs) have been conventionally bifurcated into two distinct
categories: ``short'' and ``long'' with durations less than and greater than
two seconds respectively. However, there is a lot of literature (although with
conflicting results) regarding the existence of a third intermediate class. To
investigate this issue, we extend a recent study (arXiv:1612.08235) on
classification of GRBs to two dimensions by incorporating the GRB hardness in
addition to the observed durations. We carry out this unified analysis on GRB
datasets from four detectors, viz. BATSE, RHESSI, Swift (observed and intrinsic
frame), and Fermi-GBM. We consider the duration and hardness features in
log-scale for each of these datasets and determine the best-fit parameters
using Gaussian Mixture Model. This is followed by information theoretic
criterion (AIC and BIC) to determine if a three-component fit is favored
compared to a two-component one or vice-versa. For BATSE, we find that both AIC
and BIC show preference for three components with decisive significance. For
Fermi and RHESSI, both AIC and BIC show preference for two components, although
the significance is marginal from AIC, but decisive using BIC. For Swift
dataset in both the observed and rest frame, we find that three components are
favored according to AIC with decisive significance, and two are preferred with
BIC with marginal to strong significance.Comment: 13 pages, 10 figures. This is an extension of arXiv:1612.08235 to
two-dimension
Cosmic Neutrino Bound on the Dark Matter Annihilation Rate in the Late Universe
How large can the dark matter self-annihilation rate in the late universe be?
This rate depends on (rho_DM/m_chi)^2 , where rho_DM/m_chi is the
number density of dark matter, and the annihilation cross section is averaged
over the velocity distribution. Since the clustering of dark matter is known,
this amounts to asking how large the annihilation cross section can be.
Kaplinghat, Knox, and Turner proposed that a very large annihilation cross
section could turn a halo cusp into a core, improving agreement between
simulations and observations; Hui showed that unitarity prohibits this for
large dark matter masses. We show that if the annihilation products are
Standard Model particles, even just neutrinos, the consequent fluxes are ruled
out by orders of magnitude, even at small masses. Equivalently, to invoke such
large annihilation cross sections, one must now require that essentially no
Standard Model particles are produced.Comment: 4 pages, 2 figures; to appear in the proceedings of the TeV Particle
Astrophysics II Workshop, Madison, Wisconsin, 28-31 Aug 200
Mahim Bay: a polluted environment of Bombay
Distribution of the marine life in relation to the extent of pollution at and outside Mahim Bay was studied. A poor marine fauna at stations A and B was associated with a relatively high intensity of pollution accompanied by high BOD and nutrients and low DO levels. A distinct deterioration in the marine life and water quality along the northern part of the bay as compared to the southern part was evident. An increasing trend in the marine fauna with decreasing intensity of pollution from inside to outside the bay was noticed
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