Spatially shaping waves to penetrate deep inside a forbidden gap

It is well known that waves incident upon a crystal are transported only over a limited distance - the Bragg length - before being reflected by Bragg interference. Here, we demonstrate how to send waves much deeper into crystals, by studying light in exemplary two-dimensional silicon photonic crystals. By spatially shaping the optical wavefronts, we observe that the intensity of laterally scattered light, that probes the internal energy density, is enhanced at a tunable distance away from the front surface. The intensity is up to $100 \times$ enhanced compared to random wavefronts and extends as far as $8 \times$ the Bragg length. Our novel steering of waves inside a forbidden gap exploits the transport channels induced by unavoidable deviations from perfect periodicity, here unavoidable fabrication deviations.Comment: 7 pages, 7 figure

Entanglement properties of a quantum-dot biexciton cascade in a chiral nanophotonic waveguide

We analyse the entanglement properties of deterministic path-entangled photonic states generated by coupling the emission of a quantum-dot biexciton cascade to a chiral nanophotonic waveguide, as implemented by {\O}stfeldt et al. [PRX Quantum 3, 020363 (2022)]. We model the degree of entanglement through the concurrence of the two-photon entangled state in the presence of realistic experimental imperfections. The model accounts for imperfect chiral emitter-photon interactions in the waveguide and the asymmetric coupling of the exciton levels introduced by fine-structure splitting along with time-jitter in the detection of photons. The analysis shows that the approach offers a promising platform for deterministically generating entanglement in integrated nanophotonic systems in the presence of realistic experimental imperfections.Comment: 12 pages, 5 figure

Fabrication, micro structural and mechanical characterization of Zircon Particles (ZrSiO4) reinforced Aluminum alloy (MMCs)

549-553This paper presents the review on fabrication, Microstructural analysis, and Mechanical Characterization of Zircon silicate Particles (ZrSiO4) / Aluminum Alloy composite using the stir casting method. Aluminum alloy is known for its low density, high ratio of strength and weight, improved mechanical property, and corrosion resistance. Particulate reinforcement is widely preferred because of its isotropic properties which ease the homogenous distribution with the aluminum and its alloy. Zirconparticles (ZrSiO4) are the combination of ZrO2, SiO2, Fe3O2, TiO2, and Al2O3. This review encapsulates the recent research work on different fabrication techniques, different characterizations, Microstructural analysis, and Fractroscopic studies on different Aluminum alloy matrix and ceramic materials reinforcement combination composites which improve physical, Corrosion resistant, microstructural, and mechanical properties

Cooling effectiveness measurements of film cooling configuration on the suction and pressure surface of nozzle guide vane

Detailed experiments were carried out to obtain the film cooling effectiveness distribution on the suction and pressure surface of a nozzle guide vane provided with two pairs of film cooling hole rows on each surface. Experiments were carried out varying the blowing ratio in the range of 0.35 to 2.5 and coolant to mainstream density ratio in the range of 0.97 to 1.57. The results indicate that the magnitude of the adiabatic effectiveness was lower and the decay of adiabatic effectiveness faster on the pressure surface in comparison to those on the suction surface indicating the effect of surface radius of curvature. The film cooling effectiveness data obtained on the suction surface indicate that at higher coolant to mainstream density ratio the film effectiveness decays faster and at larger downstream distances the magnitude was lower than that for lower coolant to mainstream density ratio. The results also indicate that on the suction surface in the case of flow through both the two pairs of hole rows the effectiveness distribution downstream of the second pair of row can be estimated with satisfactory accuracy using the correlation for additive effect of film cooling. Film cooling effectiveness data can be used to estimate the adiabatic wall temperature and hence the estimation of blade metal temperatures

Spatially shaping waves to penetrate deep inside a forbidden gap

It is well known that waves incident upon a crystal are transported only over a limited distance - the Bragg length - before being reflected by Bragg interference. Here, we demonstrate how to send waves much deeper into crystals, by studying light in exemplary two-dimensional silicon photonic crystals. By spatially shaping the optical wavefronts, we observe that the intensity of laterally scattered light, that probes the internal energy density, is enhanced at a tunable distance away from the front surface. The intensity is up to $100 \times$ enhanced compared to random wavefronts and extends as far as $8 \times$ the Bragg length. Our novel steering of waves inside a forbidden gap exploits the transport channels induced by unavoidable deviations from perfect periodicity, here unavoidable fabrication deviations

A study of prognosis and outcome of COVID-19-infected hypertensive patients on angiotensin-converting enzyme inhibitors/angiotensin receptor blockers

Background and Objective: COVID-19 is a pandemic caused by the virus severe acute respiratory syndrome coronavirus-2. The mortality in susceptible populations with chronic pulmonary disease, cardiac ailments, kidney disease, diabetes, and hypertension is high. While the role of angiotensin-converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARBs) in contracting novel coronavirus has clearly been elucidated, there remains uncertainty in the prognosis and outcome of COVID-19-infected patients on ACE inhibitors and ARBs. The current study was conducted to find whether these medications bore any significance in the prognosis and outcome of hypertensive patients with COVID-19 infection. Materials and Methods: This is a retrospective cohort study. We studied 96-admitted hypertensive patients with pneumonia due to COVID-19 in Krishna Rajendra Hospital at Mysore during April 2021. Patients were categorized into two groups based on antihypertensive treatment: (1) Those on ACEi/ARBs (n = 33) and (2) Those on non-ACEi/ARBs (n = 66). We analyzed the parameters such as duration of hypertension, comorbidities, mode of oxygen/pressure support delivery, duration of hospital stay, and mortality among the two groups. Results: 65.6% of patients were on non-ACEi/ARBs, 10.4% on ACE inhibitors, and 24% on ARBs. Of the patients on non-ACEi/non-ARBs, 51% were on supplemental oxygen, 20.8% were on NIV, 6.3% were intubated, and 21.9% did not require oxygen. Of those on ACEi, 63.6% were on supplemental oxygen, 15.2% were on NIV, none were intubated, and 21.2% did not require oxygen. Of those on ARBs, 53.3% were on supplemental oxygen, 18.5% were on NIV, 5.4% were intubated, and 22.8% did not require oxygen. 62.5% of patients on non-ACEi/ARBs recovered, whereas 37.5% succumbed. 83.3% of patients on ACEi recovered, whereas 16.7% succumbed. 65.2% of patients on ARBs recovered, whereas 34.8% succumbed. There was no significant correlation between non-ACEi/ARBs, ACEi, and ARBs with duration of hypertension (P = 0.092), sex (P = 0.189), mode of oxygen/pressure support delivery (P = 0.313), ward/intensive care unit stay (P = 0.624), and the final outcome of the patient (P = 0.734). Conclusion: In the population studied, the use of ACEi/ARBs in COVID-positive hypertensives was not associated with adverse outcomes as compared to those on non-ACEi/non-ARBs

Experimental probe of a complete 3D photonic band gap

The identification of a complete three-dimensional (3D) photonic band gap in real crystals always employs theoretical or numerical models that invoke idealized crystal structures. Thus, this approach is prone to false positives (gap wrongly assigned) or false negatives (gap missed). Therefore, we propose a purely experimental probe of the 3D photonic band gap that pertains to many different classes of photonic materials. We study position and polarization-resolved reflectivity spectra of 3D inverse woodpile structures that consist of two perpendicular nanopore arrays etched in silicon. We observe intense reflectivity peaks $(R > 90\%)$ typical of high-quality crystals with broad stopbands. We track the stopband width versus pore radius, which agrees much better with the predicted 3D photonic band gap than with a directional stop gap on account of the large numerical aperture used. A parametric plot of s-polarized versus p-polarized stopband width agrees very well with the 3D band gap and is model-free. This practical probe provides fast feedback on the advanced nanofabrication needed for 3D photonic crystals and stimulates practical applications of band gaps in 3D silicon nanophotonics and photonic integrated circuits, photovoltaics, cavity QED, and quantum information processing.Comment: 11 pages, 12 figure