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Influence of stretch and temperature on the energy density of dielectric elastomer generators

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Applied Mathematics and Mechanics(English Edition) 2019年第11期40卷 1547-1560页

作者： h.KhAJEhSAEID h.BAGhShOMAL AZAR School of Engineering-Emerging Technologies University of Tabriz

Application of dielectric elastomers (DE) has remarkably increased in mechatronics because they are suitable candidates for energy harvesting due to their low cost,light weight,and high energy *** dielectric elastomer generators (DEGs) exhibit high performance regardless of the applications ***,functioning as a generator,a DE may lose its efficiency due to several failure modes including material rupture,loss of tension (LT),electrical breakdown (EB),and electromechanical instability (EMI).The failure modes confine the area of allowable states for generation *** constant and dielectric strength of such elastomers depend on the amount of applied deformation and also working temperature,which are often ignored in theoretical *** this paper,variations of the above-mentioned parameters are considered in mechanical and electrical modellings to investigate their effects on energy density and efficiency of *** results show that,ignoring the variations of material dielectric constant and dielectric strength leads to overestimation of the specific ***,it is shown that,for an acrylic-based generator,the specific energy sharply decreases with temperature rise.

关键词： renewable energy dielectric elastomer generator (DEG) stretch temperature

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

Quantitative hazard assessment for Zonguldak Coal Basin underground mines

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International Journal of Mining Science and Technology 2019年第3期29卷 453-467页

作者： h.h.Erdogan h.S.Duzgun A.S.Selcuk-Kestel Directorate for Strategy Development Ministry of Energy and Natural ResourcesAnkara 06520Turkey Department of Mining Engineering Colorado School of MinesIL 80401USA Institute of Applied Mathematics Middle East Technical UniversityAnkara 06531Turkey

Underground coal mining is one of the most dangerous occupations throughout the *** reasons behind an underground occupational accident are too complex to analyze mainly due to many uncertainties which may arise from geological,operational conditions of the mine or individual characteristics of *** study proposes implementing a quantitative methodology for the analysis and assessment of hazards associated with occupational *** application of the proposed approach is performed on the mines of Turkish hard Coal Enterprises(TTK).The accidents in TTK between the years 2000 and 2014 are firstly statistically analyzed with respect to the number,type and location of accidents,age,experience,education level and main duty of the casualties and also injuries resulting from such *** hazards are classified as individual,operational and locational hazards and quantified using contingency tables,conditional and total probability *** and upper boundaries of hazards are determined and event trees for each hazard class are *** hazard evaluation results show that Armutcuk,Karadon and Uzulmez mines have relatively high hazard levels while Amasra and Kozlu mines have relatively lower hazard values.

关键词： Underground coal mining Occupational accidents hazard assessment Contingency tables Zonguldak Coal Basin

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

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Chinese Physics B 2017年第2期26卷 313-319页

作者： h Vosoughian Z Riazi h Afarideh G Sarri Laser and Optic Institute Nuclear Science and Technology Research Institute Tehran Iran physics and Accelerator School Nuclear Science and Technology Research Institute Tehran Iran Department of Energy Engineering and Physics Amirkabir University of Technology P. O. Box 15875-4413 Tehran Iran School of Mathematics and Physics The Queen's University of Belfast BT7 INN Belfast United Kingdom

The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longitudinal size shorter than the plasma wavelength, λp, instead of a periodic plasma wave, a cavity free from cold plasma electrons, called a bubble, is formed behind the laser pulse. An intense charge separation electric field inside the moving bubble can capture the electrons at the base of the bubble and accelerate them with a narrow energy spread. In the nonlinear bubble regime, due to localized depletion at the front of the pulse during its propagation through the plasma, the phase shift between carrier waves and pulse envelope plays an important role in plasma response. The carrier–envelope phase（CEP） breaks down the symmetric transverse ponderomotive force of the laser pulse that makes the bubble structure unstable. Our studies using a series of two-dimensional（2D） particle-in-cell（PIC） simulations show that the frequency-chirped laser pulses are more effective in controlling the pulse depletion rate and consequently the effect of the CEP in the bubble regime. The results indicate that the utilization of a positively chirped laser pulse leads to an increase in rate of erosion of the leading edge of the pulse that rapidly results in the formation of a steep intensity gradient at the front of the pulse. A more unstable bubble structure, the self-injections in different positions, and high dark current are the results of using a positively chirped laser pulse. For a negatively chirped laser pulse, the pulse depletion process is compensated during the propagation of the pulse in plasma in such a way that results in a more stable bubble shape and therefore, a localized electron bunch is produced during the acceleration process. As a result, by the proper choice of chirping, one can tune the number of self-injected electrons, the size of accelerated bunch

关键词： bubble regime plasma wake field positively chirped laser pulse

SYNThESIS, ChARACTERIZATION AND SPECTROSCOPIC INVESTIGATION OF PYRAZINOPORPhYRAZINE NETWORK POLYMER-SUPPORTED METAL (Ⅱ)-BASED CATALYSTS

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Chinese Journal of Polymer Science 2013年第2期31卷 242-250页

作者： h.h. Abdel-Razik B.h. Asghar E. Kenawy Chemistry Department Faculty of Science Mansoura University Chemistry Department Faculty of Science Taif University Chemistry Department Faculty of Applied Sciences Umm Al-Qura University Chemistry Department Polymer Research Group Faculty of Science Tanta University

Chloranil through condensation reaction with vicinal diamine such as diaminomaleonitrile produced heterocyclic monomer, p-benzoquinonebis[2,3-b; 2＇,3＇-b＇]pyrazine-5,6-dinitrile. The tetranitrile monomer was cyclo-tetramerised using lithium/pentanol and acetic acid affording the corresponding tetrap-benzoquinone bis[2,3-b; 2＇,3＇-b＇]pyrazinoporphyrazine）]- based network polymer （2h-Pz）. The tetranitril monomer was cyclo-tetramerised using metal salt and quinoline affording the corresponding porphyrazinato-metal II-based network polymers （M-Pz）, M = Co, Ni or Cu. Elemental analytical results, IR and NMR spectral data of the prepared molecules are consistent with their assigned formulations. Molecular masses and metal contents of the synthesized polymers proved to be of high molecular masses which confirm the efficiency of tetramerization polymerization and complexation reactions. The prepared pyrazinoporphyrazines were used as efficient catalysts for the oxidation of thiophenol and benzylthiol to their disulfides in the presence of air atmosphere. The results of oxidation of thiophenol and benzylthiol show that after 15 min the maximum yield of the corresponding disulfides reached 95%, 91%, respectively.

关键词： Pyrazinoporphyrazine Polymer-supported metal (II)-based catalysts Chloranil.

Comment on 'Mathematical structure of the three-dimensional (3D) Ising model'

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Chinese Physics B 2013年第8期22卷 356-360页

作者： Jacques h. h. Perk Department of Physics Oklahoma State UniversityStillwater OK 74078-3072 USA

The review paper by Zhang Zhi-Dong （Zhang Z D 2013 Chin. Phys. B 22 030513, arXiv：1305.2956） contains many errors and is based on several earlier works that are equally wrong.

关键词： Ising model Lie algebra series analysis thermodynamic limit

Quantum correlations and optical effects in a quantum-well cavity with a second-order nonlinearity

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Communications in Theoretical Physics 2021年第11期73卷 93-101页

作者： h Jabri higher Institute of Biotechnology of Beja University of JendoubaBeja 9000.Tunisia

In this paper,we investigate the photon correlations and the statistical properties of light produced by an optical cavity with an embedded quantum well interacting with squeezed *** show that the squeezed source substantially improves the intensity of the emitted light and generates a narrowing and a duplication of the spectrum *** a strong dependence on frequency detuning,the cavity produces considerably squeezed radiation,and perfect squeezing is predicted for weak light–matter ***,the system under consideration presents a bunching effect of the transmitted radiation resulting from weak pumping of the coherent *** results obtained may have potential applications in the fields of very accurate measurement and quantum computing.

关键词： quantum-well cavity second-order nonlinearity quantum fluctuations nonclassical effects

Calculation of the Specific heats for the Ⅱ—Ⅲ and Ⅱ—Ⅳ Phase transitions in Nh4I

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Chinese Physics Letters 2003年第1期20卷 35-38页

作者： h.Yurtseven h.Kaya Departmentofphysics IstanbulTechnicalUniversityMaslakIstanbulTurkey

This study gives our calculation for the specific heats CVI due to an Ising model using the observed CP data for the II-III and II-IV phase transitions in Nh4I. By fitting to the CP data we determine the values of the critical exponent for the pressure of 0.14 GPa (II-III phase transition) and for the pressures of 0.75, 1.35 and 1.97 GPa (II-IV phase transition) in Nh4I. Our exponent values are close to the predicted values of the specific heat in a three-dimensional Ising model. Our calculated CVI are in good agreement with the experimental CP for Nh4I in most cases.

关键词： Specific heat

Chronic disseminated candidiasis complicated with a ruptured intracranial fungal aneurysm in ALL

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World Journal of hematology 2014年第2期3卷 44-48页

作者： Teppei Okawa Toshiaki Ono Akifumi Endo Masatoshi Takagi Masayuki nagasawa Department of Developmental Biology Post Graduate School Tokyo Medical and Dental University Department of hematology Oncology and Immunology Tokyo Bay Urayasu/Ichikawa Medical Center

An 11-year-old boy with acute lymphocytic leukemia(ALL) contracted disseminated candidiasis during induction therapy, which was complicated with rupture of a fungal cranial aneurysm. Ventricular drainage and coil embolization of a residual aneurysm in combination with intensive antifungal therapy rescued the patient. Although clinical improvement was achieved, high fever and elevated levels of C-reactive protein and β-D-glucan continued for more than 10 mo. One year later, the ALL relapsed during maintenance therapy with methotrexate and 6-mercaptopurine. After salvage chemotherapy, the patient received unrelated bone marrow transplantation(BMT) in a non-complete remission condition and survived. During subsequent chemotherapy and BMT, no recurrence of the fungal infection was observed under the prophylactic anti-fungal therapy with micafungin.

关键词： Disseminated candidiasis β-D-glucan Fungal cranial aneurysm Acute lymphocytic leukemia Bone marrow transplantation