Research Activities on a MIR-FEL and Table-Top THz Generation in Kyoto University

H. Ohgaki,T. Kii,K. Masuda,M. A. Bakr,K. Higashimura,R. Kinjo,S. Ueda,T. Sonobe,Y. U. Jeong,K. Yoshida 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.21

Free Electron Lasers (FEL), which could be useful for developing energy materials, have been exploited at the Institute of Advanced Energy, Kyoto University. A mid-infrared FEL has been developed, and FEL gain saturation at 13.2 µm was achieved for the first time in May 2008. A FEL beam characterization was performed. A macro pulse energy of 5 mJ/pulse and a peak power of about 3 MW were achieved. A FEL beam transport system was constructed in the user room. Furthermore a tabletop THz FEL amplifier for the spectral range from 150 to 300 µm, which consists of a photocathode RF gun and an undulator, has been proposed to strengthen the materials research. For evaluation of the proposed design, a start-to-end simulation was carried out. An output power of about 350 kW is expected with the proposed system. Free Electron Lasers (FEL), which could be useful for developing energy materials, have been exploited at the Institute of Advanced Energy, Kyoto University. A mid-infrared FEL has been developed, and FEL gain saturation at 13.2 µm was achieved for the first time in May 2008. A FEL beam characterization was performed. A macro pulse energy of 5 mJ/pulse and a peak power of about 3 MW were achieved. A FEL beam transport system was constructed in the user room. Furthermore a tabletop THz FEL amplifier for the spectral range from 150 to 300 µm, which consists of a photocathode RF gun and an undulator, has been proposed to strengthen the materials research. For evaluation of the proposed design, a start-to-end simulation was carried out. An output power of about 350 kW is expected with the proposed system.

Eco-friendly Synthesis of New Polyfunctional Azo Dyes Using Shrimp Chitin as a Catalyst: Application on Polyester Fabrics and Their Biological Activities

Entesar A. Hassan,Hamada M. Mashaly,Zeinab M. Hashem,Salem E. Zayed,Ahmed M. Abo-Bakr 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

A series of varying and poly-functionalized heterocyclic compounds 3a-c, 4d-k, 6a,b, 8, 9, and 12 containing azofunction have been synthesized using 2-(1-(4-aminophenyl)ethylidene)malononitrile (1) and/or its diazonium salt as buildingblocks. In addition, new pyridazine derivatives 4a-c, 7a,b, and 13a-f were synthesized. Subsequent treating of the resultedazo dyes moieties with different reagents in conventional and green conditions using microwave irradiation and shrimp chitinas a green catalyst; homo- and hetero-molecules containing azo dyes were gathered. The obtained azo dyes were applied onfabrics at high temperatures and their properties such as washing fastness using standard soap (SDS) and rubbing fastness(wet and dry) under controlled conditions of pressure, speed, and moisture were studied. In addition, they were screened fortheir biological activities on two bacterial and two mycolic species. The synthesized products were characterized by theirelemental and spectral analyses such as IR, MS, 1H-NMR, and 13C-NMR spectra. The produced dyestuffs 3a-c, 4d, f, h, i, j,6a,b, 8, and 12 were dyed on polyester fabrics, and subsequently their dyeing properties and their light, washing, perspiration,rubbing, and sublimation fastness was determined and the dyed samples showed very good fastness levels to rubbing,washing, thermal fixation, good light, and possessed very good perspiration fastness.

First upper limits on the radar cross section of cosmic-ray induced extensive air showers

Abbasi, R.U.,Abe, M.,Abou Bakr Othman, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Besson, D.,Blake, S.A.,Byrne, M.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chib North-Holland 2017 Astroparticle physics Vol.87 No.-

<P>TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (similar to 10 mu s) and exhibit rapidly changing frequency, with rates on the order 1 MHz/mu s. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector. (C) 2016 Elsevier B.V. All rights reserved.</P>

A semi-analytical study on the nonlinear pull-in instability of FGM nanoactuators

Mohamed A. Attia,Rasha M. Abo-Bakr 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.4

In this paper, a new semi-analytical solution for estimating the pull-in parameters of electrically actuated functionally graded (FG) nanobeams is proposed. All the bulk and surface material properties of the FG nanoactuator vary continuously in thickness direction according to power law distribution. Here, the modified couple stress theory (MCST) and Gurtin-Murdoch surface elasticity theory (SET) are jointly employed to capture the size effects of the nanoscale beam in the context of Euler-Bernoulli beam theory. According to the MCST and SET and accounting for the mid-plane stretching, axial residual stress, electrostatic actuation, fringing field, and dispersion (Casimir or/and van der Waals) forces, the nonlinear nonclassical equation of motion and boundary conditions are obtained derived using Hamilton principle. The proposed semi-analytical solution is derived by employing Galerkin method in conjunction with the Particle Swarm Optimization (PSO) method. The proposed solution approach is validated with the available literature. The freestanding behavior of nanoactuators is also investigated. A parametric study is conducted to illustrate the effects of different material and geometrical parameters on the pull-in response of cantilever and doubly-clamped FG nanoactuators. This model and proposed solution are helpful especially in mechanical design of micro/nanoactuators made of FGMs.

Application of MIR-FEL Irradiation to Selectively Excite Phonons in Wide-gap Semiconductors

Kyohei Yoshida,Taro Sonobe,M. A. Bakr,Y. W. Choi,Ryota Kinjo,M. Omer,Masato Takasaki,Satoshi Ueda,Naoki Kimura,Keiichi Ishida,Kai Masuda,Toshiteru Kii,Hideaki Ohgaki 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.51

A mid-infrared free electron laser (MIR-FEL) (5 - 20 μm) facility (KU-FEL: Kyoto University Free Electron Laser) was constructed to aid in various energy science researchers at the Institute of Advanced Energy, Kyoto University. In May 2008, the first power saturation at 13.2 μm was achieved. A pilot application to evaluate selective phonon excitation processes in solid materials by irradiating with MIR-FEL was implemented, and a preliminary experiment without FEL irradiation was conducted. N-doped silicon carbide (SiC) was selected as a sample material due to its unique electrical property where the lattice vibration and electronic structure are coupled. Two peaks at 1.8 - 2.4 eV and 2.4 - 2.8 eV, which showed strong temperature dependences in both their intensities and peak energy, were observed. These tendencies could be explained by a donor-acceptor pair luminescence (DAP) model with impurity and defects in the SiC sample. The results imply that we can verify the selective phonon excitation by investigating the change of PL spectrum introduced by MIR-FEL irradiation.

Factors affecting in vitro embryo production: insights into dromedary camel

Adel R. Moawad,Ibrahim M. Ghoneim,Gamal M. Darwish,Magdy R. Badr,Diya A. El-Badry,Abou Bakr A. EL-Wishy 사단법인 한국동물생명공학회 2020 한국동물생명공학회지 Vol.35 No.2

The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.

Factors affecting in vitro embryo production: insights into dromedary camel

Adel R. Moawad,Ibrahim M. Ghoneim,Gamal M. Darwish,Magdy R. Badr,Diya A. El-Badry,Abou Bakr A. EL-Wishy 한국동물생명공학회(구 한국동물번식학회) 2020 Journal of Animal Reproduction and Biotechnology Vol.35 No.2

The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.

Management of the Most Common Functional Gastrointestinal Disorders in Infancy: The Middle East Expert Consensus

Indrio, Flavia,Enninger, Axel,Aldekhail, Wajeeh,Al-Ghanem, Ghanem,Al-Hussaini, Abdulrahman,Al-Hussaini, Bakr,Al-Refaee, Fawaz,Al-Said, Khoula,Eid, Bassam,Faysal, Wafaa,Hijazeen, Ruwaida,Isa, Hasan M.A The Korean Society of Pediatric Gastroenterology 2021 Pediatric gastroenterology, hepatology & nutrition Vol.24 No.4

The occurrence of functional gastrointestinal disorders (FGIDs) is a formidable challenge for infants, parents, and healthcare professionals. Although data from the Middle East are scarce, experts consider FGIDs a prevalent condition in everyday clinical practice. The new Rome IV criteria revisited the definitions from a clinical perspective to provide a practical and consistent diagnostic protocol for FGIDs. However, the treatment practices for functional disorders vary considerably among Middle Eastern countries, often resulting in mismanagement with unnecessary investigations and treatments. In addition, the role of various treatment modalities, including probiotics such as Lactobacillus reuteri DSM 17938, in FGIDs requires further discussion and evaluation. During a consensus meeting, a locally relevant approach for treating common FGIDs such as infant regurgitation, infant colic, and functional constipation was discussed and approved by regional experts. The participants suggested a simplified treatment plan and protocol for general pediatricians and other primary care physicians managing FGIDs. This easy-to-follow standardized protocol will help streamline the initial management of this complex disorder in the Middle East region and even globally.