Polyvinylpyrrolidone-bromine complex: An efficient polymeric reagent for selective preparation of benzyl bromides in the presence of hexamethyldisilane

Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone-bromine complex (PVPP-Br2)/hexamethyldisilane in chloroform at reflux condition. Selective conversion of benzyl alcohol to benzyl bromide in the presence of primary aliphatic alcohols, e.g. 2-phenylethanol was also achieved. KEY WORDS: Polyvinylpyrrolidone-bromine, Benzyl bromide, Hexamethyldisilane, Selective bromination Bull. Chem. Soc. Ethiop. 2012, 26(2), 305-309.DOI: http://dx.doi.org/10.4314/bcse.v26i2.1

Violating Bell inequality using weak coherent states

We present an experimental investigation of two-photon interference using a continuous-wave laser. We demonstrate the violation of the CHSH inequality using the phase randomized weak coherent states from a continuous wave laser. Our implementation serves as an approach to reveal the quantum nature of a source that is considered to be a classical source.Comment: 6 pages, 2 figure

Nonlinear structures: explosive, soliton and shock in a quantum electron-positron-ion magnetoplasma

Theoretical and numerical studies are performed for the nonlinear structures (explosive, solitons and shock) in quantum electron-positron-ion magnetoplasmas. For this purpose, the reductive perturbation method is employed to the quantum hydrodynamical equations and the Poisson equation, obtaining extended quantum Zakharov-Kuznetsov equation. The latter has been solved using the generalized expansion method to obtain a set of analytical solutions, which reflect the possibility of the propagation of various nonlinear structures. The relevance of the present investigation to the white dwarfs is highlighted.Comment: 7 figure

Dynamics of laser-bumped electron–hole semiconductor plasma

Electron–hole pairs in semiconductors can be stimulated by a laser beam with energy larger than the energy gap of the semiconductor. The interaction between an electron–hole plasma with a laser beam can be a source of instability. The dependence of the instability on the electron and hole temperatures and the unperturbed potential of the incident laser are examined. Using Maxwell’s equations along with electron–hole fluid equations, an evolution equation describing the system is obtained. The latter is reduced to an energy equation that characterizes localized pulse propagation

Controlling the Density of Plasma Species in Ar/CF4 Radiofrequency Capacitively Coupled Plasma Discharges

In this manuscript, a fluid model is utilized to calculate the density of plasma species assuming geometrically symmetric Ar/CF4 Radiofrequency Capacitively Coupled Plasmas. The electrodes are driven by a sinusoidal waefront with an amplitude of 200 V and a frequency of 13.56 MHz. The gap between the electrodes is 5cm. The plasma species density is calculated as a function of the gas pressure, electron temperature, and the gas composition. In a good agreement with recent experimental results, $CF^+_3$ and F are dominant for all considered simulation parameters. The results explain the pathways to perform atomic layer etching and nanolayer deposition processes. In order to reveal the effect of electron heating on the discharge dynamics, The spatiotemporal electron energy equation is coupled to the fluid model. Tailoring the driven potential has been found to control the concentration of some plasma species. When the plasma is driven with the fundamental frequency, Ohmic and stochastic heating allows electrons to be heated symmetrically. Higher harmonics give rise to an electrical asymmetry and electron heating asymmetry between the powered and grounded sheaths. The electron temperature depends on the driven harmonics; it adjusts gain and loss rates and some plasma species densities

Analytical model of asymmetrical Mixed-Mode Bending test of adhesively bonded GFRP joint

This paper presents new analytical model of asymmetric mixed-mode bending (MMB) specimen of adhesively bonded pultruded GFRP joints. An easily applicable relationship for the calculation of the strain energy release rate of the asymmetric MMB specimens is proposed based on the beam theory. The model is capable to analyze stacking sequence as well as various crack propagation paths. In the paper the effect of the various fiber bridging length and different crack propagation paths is analyzed analytically and supported by experimental results. The methodology and results presented in this paper could be utilized for the design of both joint geometry and lay-up of the laminates constituting the joint or for the prediction of the fracture behavior of such structures

Interpretation of localized surface nano-structures

Recent experiment was done to create surface nano-structures by extrusion of slow highly charged ions with LiNbO_3 single crystal. In this paper, we suggest a mechanism based on plasma expansion approach to explain the formation of the surface nano-structures. Furthermore, the effects of the physical parameters of the non-Maxwellian plasma on the created structures are examined

PENGARUH PELATIHAN DARING DAN KESIAPAN TEKNOLOGI TERHADAP MOTIVASI BERWIRAUSAHA UMKM DI INDONESIA (STUDI PADA UMKM DI 5 DESTINASI SUPER PRIORITAS DAN BALI))

This study aims to determine the extent of the influence of online training and technology readiness on entrepreneurial motivation, especially for MSMEs from 5 Super Priority Destinations and Bali who take part in online training organized by Telkom University in collaboration with the Ministry of Tourism and Creative Economy. To increase MSMEs' knowledge of digital business management, online training is currently trending. One of the challenges in conducting online training is the readiness and understanding of the technology of the participants. Based on the description above, it is necessary to know how much influence training and technology readiness have on SME entrepreneurship motivation in 5 Super Priority Destinations (Lake Toba, Borobudur, Mandalika, Likupang, and Labuan Bajo) and Bali. The population in this study were 300 SMEs spread across 5 Super Priority Destinations and Bali who participated in online training activities. Structured questionnaires were given to MSME actors to test hypotheses. Data processing will be analyzed using path analysis. Based on the results of the study it can be concluded that online training has an effect on technological readiness, and technology readiness on entrepreneurial motivation, the rest is still influenced by other variables.Penelitian ini bertujuan untuk mengetahui sejauh mana pengaruh pelatihan online dan kesiapan teknologi terhadap motivasi berwirausaha khususnya bagi UMKM dari 5 Destinasi Super Prioritas dan Bali yang mengikuti pelatihan online yang diselenggarakan oleh Telkom University bekerjasama dengan Kementerian Pariwisata dan Ekonomi Kreatif. Untuk meningkatkan pengetahuan UMKM tentang manajemen bisnis digital, saat ini sedang tren pelatihan online. Salah satu tantangan dalam melakukan pelatihan online adalah kesiapan dan pemahaman teknologi peserta. Berdasarkan uraian di atas, perlu diketahui seberapa besar pengaruh pelatihan dan kesiapan teknologi terhadap motivasi berwirausaha UKM di 5 Destinasi Super Prioritas (Danau Toba, Borobudur, Mandalika, Likupang, dan Labuan Bajo) dan Bali. Populasi dalam penelitian ini adalah 300 UKM yang tersebar di 5 Destinasi Super Prioritas dan Bali yang mengikuti kegiatan pelatihan secara online. Kuesioner terstruktur diberikan kepada para pelaku UMKM untuk menguji hipotesis. Pengolahan data akan dianalisis menggunakan analisis jalur. Berdasarkan hasil penelitian dapat disimpulkan bahwa pelatihan online berpengaruh terhadap kesiapan teknologi, dan kesiapan teknologi terhadap motivasi berwirausaha, sisanya masih dipengaruhi oleh variabel lain

Two kinds of rogue waves of the general nonlinear Schr\"odinger equation with derivative

In this letter,the designable integrability(DI) of the variable coefficient derivative nonlinear Schr\"odinger equation (VCDNLSE) is shown by construction of an explicit transformation which maps VCDNLSE to the usual derivative nonlinear Schr\"odinger equation(DNLSE). One novel feature of VCDNLSE with DI is that its coefficients can be designed artificially and analytically by using transformation. What is more, from the rogue wave and rational traveling solution of the DNLSE, we get two kinds of rogue waves of the VCDNLSE by this transformation. One kind of rogue wave has vanishing boundary condition, and the other non-vanishing boundary condition. The DI of the VCDNLSE also provides a possible way to control the profile of the rogue wave in physical experiments.Comment: 8 pages, 5 figure