205 research outputs found
Low electric field induction in BaTiO3-epoxy nanocomposites
Epoxy is widely used material, but epoxy has limitations in terms of brittleness in failure, and thus researchers
explore toughening and strengthening options such as adding a second phase or using electromagnetic fields
to tailor toughness and strength, on demand and nearly instantaneously. Such approach falls into the category
of active toughening but has not been extensively investigated. In this research, Si-BaTiO3 nanoparticles were
used to modify the electro-mechanical properties of a high-performance aerospace-grade epoxy so as to study
its response to electric fields, specifically low field strengths. To promote uniform dispersion and distribution, the Si-BaTiO3 nanoparticles were functionalised with silane coupling agents and mixed in the epoxy Araldite LY1564
at different content loads (1, 5, 10 wt%), which was then associated with its curing agent Aradur 3487. Real-time
measurements were conducted using Raman spectroscopy while applying electric fields to the nanocomposite
specimens. The Raman data showed a consistent trend of increasing intensity and peak broadening under
the increasing electric field strength and Si-BaTiO3 contents. This was attributed to the BaTiO3 particles’ dipolar displacement in the high-content nanocomposites (i.e., 5 wt% and 10 wt%). The study offers valuable insights on how electric field stimulation can actively enhance the mechanical properties in epoxy composites, specifically in
relatively low fields and thin, high-aspect-ratio composite layers which would require in-situ mechanical testing
equipped with electric field application, an ongoing investigation of the current research
Functional Antigenic Molecules of Different Life-Stages of Rodent Filariid, Acanthocheilonema viteae and Their Cross Reactivity with Human Filarial (Wuchereria bancrofti) Sera.
Proteins obtained by SDS-solubilisation of various developmental stages (adults, uterus contents, microfilariae and infective larvae) of the filariid Acanthocheilonema viteae were separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and electrophoretically transferred onto nitrocellulose filter sheets. The results showed minor differences in the protein pattern of adult worms, microfilariae, uterine contents and infective larvae. Immunoperoxidase staining of these antigens with infected mastomys sera showed that maximum number of antigens in infective larval stage were identified by the sera collected at prepatent stage of infection whereas in adult antigen maximum bands were recognized by sera from patent infection. A large number of microfilarial antigens were found to be immunoreactive during patent stage but only a few remained functional during latency. Uterine antigens possess a number of immunoreactive components which reacted with antibodies in sera of all stages of infection with maximum recognition by patent (microfilaraemic) serum. Cross reaction between A. viteae antigen and W. bancrofti human sera led to identification of a few common molecules which demonstrated the usefulness of antigens of rodent filariid A. viteae in immunodiagnosis or in evolving strategies for vaccination against human filariasis
Finite size effects with variable range exchange coupling in thin-film Pd/Fe/Pd trilayers
The magnetic properties of thin-film Pd/Fe/Pd trilayers in which an embedded
~1.5 A-thick ultrathin layer of Fe induces ferromagnetism in the surrounding Pd
have been investigated. The thickness of the ferromagnetic trilayer is
controlled by varying the thickness of the top Pd layer over a range from 8 A
to 56 A. As the thickness of the top Pd layer decreases, or equivalently as the
embedded Fe layer moves closer to the top surface, the saturated magnetization
normalized to area and the Curie temperature decrease whereas the coercivity
increases. These thickness-dependent observations for proximity-polarized
thin-film Pd are qualitatively consistent with finite size effects that are
well known for regular thin-film ferromagnets. The critical exponent of
the order parameter (magnetization) is found to approach the mean field value
of 0.5 as the thickness of the top Pd layer increases. The functional forms for
the thickness dependences, which are strongly modified by the nonuniform
exchange interaction in the polarized Pd, provide important new insights to
understanding nanomagnetism in two-dimensions.Comment: 14 pages, 5 figures, submitted to JMM
Real clocks and the Zeno effect
Real clocks are not perfect. This must have an effect in our predictions for
the behaviour of a quantum system, an effect for which we present a unified
description encompassing several previous proposals. We study the relevance of
clock errors in the Zeno effect, and find that generically no Zeno effect can
be present (in such a way that there is no contradiction with currently
available experimental data). We further observe that, within the class of
stochasticities in time addressed here, there is no modification in emission
lineshapes.Comment: 12 a4 pages, no figure
Dietary Pattern of Schoolgoing Adolescents in Urban Baroda, India
Diet plays a very important role in growth and development of
adolescents, during which the development of healthy eating habits is
of supreme importance. There is a dual burden of undernutrition and
overnutrition in this age-group. The study assessed the food habits,
food preferences, and dietary pattern of schoolgoing urban adolescents
in Baroda, India. Both quantitative and qualitative methods were used
in this study. A quantitative survey was carried out using a pre-tested
self-administered structured questionnaire among 1,440 students from
class 6 to 12 in 7 English medium and 23 Gujarati medium schools. Focus
group discussions, 5 each with adolescent boys and girls, were held,
along with 5 focus group discussions with teachers of Gujarati and
English medium schools. Nearly 80% of adolescents had consumed regular
food, like dal, rice, chapati, and vegetables, including green leafy
vegetables. Nearly 50% of them had consumed chocolates, and about
one-third consumed fast foods. Nearly 60% of adolescents had their
breakfast daily while the remaining missed taking breakfast daily.
Nearly one-third of adolescents were missing a meal once or twice a
week. A large majority had consumed regular foods. However, more than
half of them had consumed chocolates, soft drinks, and over one-third
had taken fast foods
Solar powered vapor absorption system using propane and alkylated benzene AB300 oil
This paper describes experimental work on a solar assisted vapour absorption air conditioning system using Propane (refrigerant) and Alkylated Benzene (AB300-refrigeration lubrication oil, absorbent). Preliminary experiments to assess the miscibility of propane in various lubricating oils namely Shell Clavus oils 32 and 64 and Alkylated Benzene oils AB150 and AB300 indicated that Propane is most miscible in Alkylated Benzene AB300. The vapour absorption system is a single stage absorption consisting of evaporator, absorber, generator and condenser. The system is equipped with heat pipes installed between the absorber and the pre-generator to recover the heat of absorption. The heat applied to the generator replicated the solar thermal energy based on the climatic conditions of Jamaica using flat plate collectors commonly used in Jamaica. Experiments at various evaporator, absorber and generator temperatures showed that the coefficient of performance of the system increases with increasing the generator temperature and with decreasing the absorber temperatures. The solar fraction for the flat plate collectors to produce the generator temperature needed to drive the absorption system is up to 50%
Improving community health through marketing exchanges: A participatory action research study on water, sanitation, and hygiene in three Melanesian countries
Diseases related to poor water, sanitation and hygiene (WaSH) are major causes of mortality and morbidity. While pursuing marketing approaches to WaSH to improve health outcomes is often narrowly associated with monetary exchange, marketing theory recognises four broad marketing exchange archetypes: market-based, non-market-based, command-based and culturally determined. This diversity reflects the need for parameters broader than monetary exchange when improving WaSH. This study applied a participatory action research process to investigate how impoverished communities in Melanesian urban and peri-urban informal settlements attempt to meet their WaSH needs through marketing exchange. Exchanges of all four archetypes were present, often in combination. Motivations for participating in the marketing exchanges were based on social relationships alongside WaSH needs, health aspirations and financial circumstances. By leveraging these motivations and pre-existing, self-determined marketing exchanges, WaSH practitioners may be able to foster WaSH marketing exchanges consistent with local context and capabilities, in turn improving community physical, mental and social health
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