The whistler nozzle phenomenon

The whistler nozzle is a simple device which can induce jet self-excitations of controllable amplitudes and frequencies and appears highly promising for many applications involving turbulent transport, combustion and aerodynamic noise. The characteristics of this curious phenomenon are documented for different values of the controlling parameters and attempts to explain the phenomenon. It is shown that the whistler excitation results from the coupling of two independent resonance mechanisms: shear-layer tone resulting from the impingement of the pipe-exit shear layer on the collar lip, and organ-pipe resonance of the pipe-nozzle. The crucial role of the shear-layer tone in driving the organ-pipe resonance is proven by reproducing the event in pipe-ring and pipe-hole configurations in the absence of the collar. It is also shown that this phenomenon is the strongest when the self-excitation frequency matches the preferred mode of the jet

Merajut Kerukunan Dalam Keragaman Agama Di Indonesia (Perspektif Nilai-nilai Al-quran)

Religious diversity is sunnatullah, something that is given. As well as thediversity in language, culture and the like. It is recognized by al-Quran clearly. Forthat al-Quran has given instructions to his people in addressing religious diversity inform two clear and unequivocal manner. That is the attitude Exclusive (al-inghilaq) inthings that are aqidah (belief) and ‘ubudiah (worship) and inclusive attitude (alinfitah)in the realm of socially interactive. In the applicative level, the teachings ofIslam which is sourced to al-Quran and Sunnah has taught his people how to live sideby side with members of different communities faith. Medina Charter is among thehistorical evidence of how Islam since the beginning wantrealization inter-religiousharmony. In the context on Indonesia, noble values al-Quran can be developed inorder uphold various pillars that need to be agreed together and actualized to buildinter-religious harmony. Among these pillars is to improve the correct tolerance, mutualrespect with full religious attitudes in certain maturity, increased cooperation in mattersof religion become destination together, without having to mutual suspicion andstrengthen the three pillars of state (Pancasila, UUD 45 and Unity in Diversity).Keywords: harmony, religious diversity,Keragaman beragama merupakan sunnatullah, sesuatu yang sifatnya given.Sebagai halnya keragaman dalam bahasa, suka dan budaya.Hal ini diakui oleh Al-Quran secara jelas.Untuk itu,Al-Quran telah memberikan petunjuk kepada umatnyadalam menyikapi keragaman beragama dalam wujud dua sikap yang jelas dantegas

Recanalization of the Chronically Occluded Internal Carotid Artery: Review of the Literature.

Introduction: We reviewed the literature on interventions for patients with medically refractory chronically occluded internal carotid artery (COICA) to assess the risks and/or benefits after recanalization via an endovascular technique (ET) or hybrid surgery (HS, i.e., ET plus carotid endarterectomy). Methods: A systematic search of the electronic databases was performed. Patients with COICA were classified into 4 different categories according to Hasan et al classification. Results: Eighteen studies satisfied the inclusion criteria. Only 6 studies involved an HS procedure. We identified 389 patients with COICA who underwent ET or HS; 91% were males. The overall perioperative complication rate was 10.1% (95% confidence interval [CI]: 7.4%-13.1%). For types A and B, the successful recanalization rate was 95.4% (95% CI: 86.5%-100%), with a 13.7% (95% CI: 2.3%-27.4%) complication rate. For type C, the success rate for ET was 45.7% (95% CI: 17.8%-70.7%), with a complication rate of 46.0% (95% CI: 20.0%-71.4%) for ET and for the HS technique 87.6% (95% CI: 80.9%-94.4%), with a complication rate of 14.0% (95% CI: 7.0%-21.8%). For type D, the success rate of recanalization was 29.8% (95% CI: 7.8%-52.8%), with a 29.8% (95% CI: 6.1%-56.3%) complication rate. Successful recanalization resulted in a symmetrical perfusion between both cerebral hemispheres, resolution of penumbra, normalization of the mean transit time, and improvement in Montreal Cognitive Assessment (MoCA) score (ΔMoCA = 9.80 points; P = 0.004). Conclusions: Type A and B occlusions benefit from ET, especially in the presence of a large penumbra. Type C occlusions can benefit from HS. Unfortunately, we did not identify an intervention to help patients with type D occlusions. A phase 2b randomized controlled trial is needed to confirm these findings

Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO3_3

Improvement in magnetic and electrical properties of multiferroic BiFeO$_3$ in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles of different sizes ranging from $\sim$ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe$^{2+}$ state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO$_3$ nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for $\sim$ 49 nm Bi$_{0.9}$Ba$_{0.1}$FeO$_3$ nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO$_3$.Comment: