169 research outputs found
Management of Foundries in Small Scale Industries
The liberalisation and globalisation of the Indian economy having gained momentum since 1991, a number of strategic challenges have to be faced by Indian industry. Organisat-ions which succeed in addressing these challenges head on are quite likely to gain enormously as they become compe-titire and make good use of strategic opportunities
Modulacijska nestabilnost visokofrekventnih površinskih valova na granici plazma – vakuum
Nonlinear propagation of surface waves in a cold electron-plasma half-space is theoretically investigated by using the method of multiple scale. It is shown that high-frequency surface waves are modulationally unstable at a plasma - vacuum interface. The growth of the modulational instability of the surface waves is discussed. It is also shown that the electric field associated with a finite amplitude surface wave can take the form of an envelope soliton which propagates along the plasma - vacuum interface with a velocity independent of the soliton height.Teorijski istražujemo nelinearno širenje površinskih valova u poluprostoru s hladnom elektronskom plazmom metodom višestruke ljestvice. Pokazuje se da su visokofrekventni površinski valovi modulacijski nestabilni na granici plazma – vakuum. Raspravlja se rast modulacijske nestabilnosti površinskih valova. Također pokazujemo da električno polje, koje je povezano s površinskim valovima konačne amplitude, može primiti oblik anvelopnog solitona koji se širi duž granice plazma – vakuum brzinom koja ne ovisi o visini solitona
Inhomogeneous polarization evolution resolves a fundamental issue in non-Hermitian transverse optical beam shifts
Depending on the system parameters, the transverse optical beam shift in
reflection can be non-Hermitian with real eigenvalues and non-orthogonal
eigenstates. We reveal that such an unusual resemblance with typical PT
(parity-time)-symmetric systems originates from the beam's momentum domain
polarization evolution. Specifically, for partial reflection, the momentum
domain inhomogeneous polarization evolution of the beam is at the heart of all
the peculiarities in the corresponding eigenspectrum of the transverse shift
operator. These findings put forward the notion of novel non-Hermitian
spin-orbit photonics and enable common polarization optical elements to act as
PT-symmetric non-Hermitian systems
Influence of the coherence of spectral domain interference of Fano resonance on the degree of polarization of light
We show an intriguing connection between the coherence of spectral domain
interference of two electromagnetic modes in Fano resonance and the resulting
degree of polarization of light. A theoretical treatment is developed by
combining a general electromagnetic model of partially coherent interference of
a spectrally narrow and a broad continuum mode leading to Fano resonance and
the cross-spectral density matrix of the interfering polarized fields of light.
The model suggests a characteristic variation of the degree of polarization
across the region of spectral dip and the peak of Fano resonance as an
exclusive signature of the connection between the degree of polarization and
the coherence of the interfering modes. The predictions of the model is
experimentally verified in the partially polarized Fano resonance spectra from
metal Chalcogenides systems, which emerged due to the interference of a narrow
excitonic mode with the background continuum of scattered light in the
reflectance spectra from the system. The demonstrated connection between
polarization and coherence in the spectral domain Fano-type interference of
electromagnetic modes is fundamentally important in the context of a broad
variety of non-trivial wave phenomena that originate from fine interference
effects, which may also have useful practical implications
The role of NGOs in improving sanitation status in the rural areas of Bangladesh: challenges and expectations
NGOs are playing a significant role to ameliorate the sanitation situation in Bangladesh. Multi-stage 30 cluster sampling was adopted to collect quantitative data and 4,200 households were visited from 10 purposively selected sub-districts with and without NGO-led WASH programme. In every sub-district a focus group discussion was conducted to collect relevant information supplementing the findings from quantitative study. The overall sanitation coverage in areas with NGO intervention was significantly (p<0.001) higher than the areas without any such intervention. Logistic regression analyses showed that the existence of NGO-led programme, the level of education, poverty, land ownership and access to media had significant (p<0.001) influence on sanitation practice. Financial crisis was reported to be the predominant reason for households not having their own sanitary latrine, where NGO assistance was sought for. People acknowledged the role of NGOs in raising awareness, increasing sanitary latrine use and reported NGO assistance necessary for 100 per cent sanitation
Diffraction of an Off-axis Vector-Beam by a Tilted Aperture
Manifestations of orbital angular momentum induced effects in the diffraction
of a radially polarized vector beam by an off-axis tilted aperture are studied
both experimentally and theoretically. Experiments were carried out to extract
the degree of circular polarization, which was shown to be proportional to the
on-axis component of the spin angular momentum density. We report a clear
separation of the regions of dominance of the right and left circular
polarizations associated with positive and negative topological charges
respectively, which is reminiscent of the standard vortex-induced transverse
shift, albeit in the diffraction scenario. The experimental results are
supported by model simulations and the agreement is quite satisfactory. The
results are useful to appreciate the orbit-orbit related effects due to
unavoidable misalignment problems (especially for vortex beams)
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