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Quantum photodetachment of hydrogen negative ion in a harmonic potential subjected to static electric field

Chinese Physics B 2019年第2期28卷 179-184页

作者： Azmat Iqbal Kiran Humayun Sana Maqsood saba jawaid Afaq Ahmad Amin Ur Rahman Bakht Amin Bacha Department of Physics The University of LahoreRaiwind Road CampusLahorePakistan Center of Excellence in Solid State Physics University of the PunjabLahorePakistan Department of Physics RIPHAH International University IslamabadPakistan Department of Physics University of Malakand Chakdara Dir(L)Pakistan

Photodetachment of negative ions has attracted immense interest owing to its fundamental nature and practical implications with regard to technology. In this study, we explore the quantum dynamics of the photodetachment cross section of negative ion of hydrogen H-in the perturbed one dimensional linear harmonic potential via static electric field. To this end,the quantum formula for total photodetachment cross section of the H-ion is derived by calculating the dipole matrix element in spherical coordinates. In order to obtain the detached electron wave function, we have solved the time-independent Schr¨odinger wave equation for the perturbed Hamiltonian of the harmonic oscillator in momentum representation. To acquire the corresponding normalized final state detached electron wave function in momentum space, we have employed an approach analogous to the WKB(Wenzel–Kramers–Brillouin) approximation. The resulting analytical formula of total photodetachment cross section depicts interesting oscillator structure that varies considerably with incident-photon energy,oscillator potential frequency, and electric field strength as elucidated by the numerical results. The current problem having close analogy with the Stark effect in charged harmonic oscillator may have potential implications in atomic and molecular physics and quantum optics.

关键词： photodetachment cross section harmonic oscillator potential Stark effect time-independent Schrodinger equation WKB approximation

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Flexural and Dynamic Mechanical Properties of Alkali-Treated Coir/Pineapple Leaf Fibres Reinforced Polylactic Acid Hybrid Biocomposites

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Journal of Bionic Engineering 2021年第6期18卷 1430-1438页

作者： Ramengmawii Siakeng Mohammad jawaid Mohammad Asim Hassan Fouad Sameer Awad Naheed saba Suchart Siengchin Department of Mechanical and Process Engineering The Sirindhorn International Thai-GermanGraduate School of Engineering(TGGS)King Mongkut’s University of Technology North BangkokBangkok10800Thailand Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra Malaysia43400 UPMSerdangSelangorMalaysia Applied Medical Science Department Community CollegeKing Saud UniversityP.O.Box 10219Riyadh11433Saudi Arabia Chemistry School of Science and TechnologyUniversity of New EnglandArmidaleNSW2351Australia

Polylactic acid(PLA)possesses good mechanical and biodegradability properties which make it a suitable material for polymer composites whereas brittleness and high costs limit its utilization in various *** reinforcement of natural fibres with biopolymers has been formed to be an efficient technique to develop composites having the ability to be fully *** study concerns with the incorporation of various percentages of untreated and alkali-treated Coir Fibres(CF)and pineapple leaf fibres(PALF)in PLA biocomposites and characterizations of flexural,morphological and dynamic mechanical *** properties showed that the treated C1P1 hybrid composites(C1P1A)displayed highest flexural strength(35.81 MPa)and modulus(5.28 GPa)among all hybrid *** Electron Microscopy(SEM)revealed a behaviour of fibre-matrix adhesion in untreated treated *** observation revealed good dispersion of the fillers in *** mechanical analysis revealed that C1P1A showed highest glass transition temperature(Tg)and storage modulus(E')while untreated C3P7 displayed the least Tg and E'.Overall findings showed that alkali-treated hybrid biocomposites(CF/PALF/PLA)especially C1P1A have improved flexural properties,dynamic and morphological properties over untreated *** of these findings will provide attracting consideration of these hybrid biocomposites for various lightweight uses in a broad selection of industrial applications such as biomedical sectors,automobile,construction,electronics equipment,and hardware tools.

关键词： Coir fibres Pineapple leaf fibres Biocomposites Polylactic acid Mechanical properties Dynamic mechanical properties

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Effect of Fiber Loadings and Treatment on Dynamic Mechanical, Thermal and Flammability Properties of Pineapple Leaf Fiber and Kenaf Phenolic Composites

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Journal of Renewable Materials 2018年第4期6卷 383-393页

作者： M.Asim M.jawaid M.Nasir N.saba Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra Malaysia43400 SerdangSelangorMalaysia Department of Chemical Engineering College of EngineeringKing Saud UniversityRiyadhSaudi Arabia Composite Wood Forest Product DivisionForest Research Institute248006 DehradunIndia

This study deals with the analysis of dynamic mechanical,thermal and flammability properties of treated and untreated pineapple leaf fiber(PALF)and kenaf fiber(KF)phenolic *** indicated that storage modulus was decreased for all composites with increases in temperature and pattern of slopes for all composites,having almost the same values of E′at glass transition temperature(Tg).The peak of the loss modulus of pure phenolic composites was shown to be much *** the addition of kenaf/PALF,peaks were higher and shifted towards a high *** Tan delta peak height was low for pure phenolic composites and maximum for 60%PALF phenolic ***-Cole analysis was carried out to understand the phase behavior of the composite *** analysis(TGA)results indicated that pure phenolic composites have better thermal stability than PALF and kenaf phenolic *** and horizontal UL-94 tests were conducted and showed pure phenolic resin is highly fire *** overall results showed that treated KF composites enhanced the dynamic mechanical and thermal properties among all PALF/KF composites.

关键词： Pineapple leaf fiber kenaf fiber phenolic resin dynamic mechanical analysis thermogravimetric analysis flammability

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Performance Evaluation of Calcium Alkali-treated Oil Palm/Pineapple Fibre/Bio-phenolic Composites

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Journal of Bionic Engineering 2022年第5期19卷 1493-1503页

作者： Sameer A.Awad Hassan Fouad Eman M.Khalaf N.saba Hom N.Dhakal M.jawaid Othman Y.Alothman Department of Chemistry School of Science and TechnologyUniversity of New EnglandArmidaleNSW 2351Australia Department of Chemistry College of Education for Pure ScienceUniversity of Al-AnbarRamadi 31001Iraq Biomedical Engineering Department Faculty of EngineeringHelwan UniversityHelwan 11792Egypt Pharmacy Department Al-Maarif University CollegeAnbar 3001 RamadiIraq Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra Malaysia43400 SerdangMalaysia Advanced Polymers and Composites(APC)Research Group School of Mechanical and Design EngineeringUniversity of PortsmouthPortsmouth PO13DJUK Department of Chemical Engineering College of EngineeringKing Saud UniversityRiyadh 11433Saudi Arabia

The utilisation of oil palm fibre(OPF)and pineapple leaf fibres(PALF)as reinforcement materials for bio-phenolic composites is growing especially in automotive lightweight *** major aim of this current study is to investigate the influence of alkali(Ca(OH)_(2)) treatment on pure and hybrid *** effects of enhancements in chemical interactions were evaluated by the Fourier-Transform Infrared Spectrometer(FTIR).Dynamic Mechanical Analysis(DMA)and Thermogravimetric Analysis(TGA)performance of untreated reinforcements(OPF and PALF)and treated(OPF/OPF)composites at varying temperature and noted sufficient interfacial bonding contributing towards the improvements in thermal *** DMA results,the storage modulus improved with treated composites while the damping factor was ***,the treated hybrid composites exhibited significant improvements in thermal stability compared to untreated fibre *** results indicated that alkali calcium hydroxide(Ca(OH2(:T)incorporation in hybrid composites(OPF/PALF)results in increased tensile strength and modulus among all ***,the alkali-treated(Ca(OH)_(2))-treated pure composite(T/50%PALF),and hybrid composites(T/1OPF.1PALF)exhibited better flexural strength as compared with other *** contrast,the T/50%PALF showed higher flexural stress of 78.2 MPa,while the flexural modulus was recorded at 6503 *** can be proposed from the findings of this study that the alkali treatment(5%Ca(OH)_(2))can be utilised to improve the strength and efficiency of agriculture biomass to be used as reinforcements in ***,the hybridisation of bio-fibre composites has the potential as a novel variety of biodegradable and sustainable composites appropriate for several industrial and engineering applications.

关键词： Hybrid fibre composites Alkali treatments Surface modifications Mechanical properties Thermal stability

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The Effect of Fibre Length on Flexural and Dynamic Mechanical Properties of Pineapple Leaf Fibre Composites

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Journal of Renewable Materials 2020年第7期8卷 833-843页

作者： A.A.Mazlan M.T.H.Sultan S.N.A.Safri N.saba A.U.M.Shah M.jawaid Department of Aerospace Engineering Faculty of EngineeringUniversiti Putra MalaysiaSerdangSelangor Darul Ehsan43400 UPMMalaysia Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)SerdangSelangor Darul Ehsan43400 UPMMalaysia Aerospace Malaysia Innovation Centre(944751-A) Prime Minister’s DepartmentMIGHT Partnership HubJalan Impact63000 CyberjayaMalaysia

The present paper deals with the effect of loading different pineapple leaf fibre(PALF)length(short,mixed and long fibres)and their reinforcement for the fabrication of vinyl ester(VE)*** of PALF/VE composites was investigated through three-point bending flexural testing and viscoelastic(dynamic)mechanical properties through dynamic mechanical analysis(DMA).DMA results revealed that the long PALF/VE composites displayed better mechanical,damping factor and dynamic properties as compared to the short and mixed PALF/VE *** flexural strength and modulus of long PALF/VE composites were 113.5 MPa and 14.3 GPa,*** storage(E′)and loss(E″)moduli increased to 2000 MPa and 225 MPa respectively for PALF/VE *** result analysis indicated that increasing the length of the reinforcement fibre results in satisfactory mechanical performance and dynamic properties of composites.

关键词： Pineapple leaf fibre vinyl ester resin flexural strength dynamical mechanical properties damping factor

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