1,721,862 research outputs found
Pemikiran politik Khalid Muhammad Khalid
Full text linkArtikel ini membahas tentang pemikiran politik Khalid Muhammad Khalid. Khalid Muhammad Khalid mengalami dualisme pemikiran politik. Pada tahun 1950an, ketika menulis “Min Hunā Nabda’” beliau berpandangan agama bukan negara, maka harus ada pemisahan antara agama dan negara. Menurutnya, harus ada pemurnian agama (Islam) dari kependetaan, menegakkan konsep sosialisme dalam kehidupan masyarakat, menjauhkan keinginan untuk memiliki pemerintahan relijius, dan memberikan kebebasan berpolitik bagi perempuan. Namun, pada tahun 1980an Khalid menulis buku “al-Daulah fi al-Islām”. Dalam bukunya tersebut, beliau merevisi pandangannya terdahulu tentang pemisahan agama dan negara, dan mengatakan bahwa agama juga mengatur negara. Maka, Islam adalah agama dan negara. Pemikirannya dipengaruhi oleh kondisi sosial politik Mesir ketika itu, dan kedekatannya dengan Ikhwan al-Muslimin. Dualisme pemikiran politik Islam Khalid Muhammad Khalid merupakan hal yang wajar dalam konteks pemikiran. Berdasarkan konsep hubungan agama dan negara, diketahui bahwa pemikiran Khalid Muhammad Khalid yang tertuang dalam buku “Min Hunā Nabda’” yang memisahkan agama dan negara termasuk tokoh dari golongan yang bersifat sekularistik. Namun, setelah perubahan pemikirannya tentang negara dalam buku “al-Daulah fi al-Islam”, yang menyatukan agama dan negara, maka Khalid Muhammad Khalid menjadi tokoh dari golongan yang bersifat simbiotik, bahwa agama dan negara saling membutuhkan
La Palmyra di Khalid Muhammad al-As'ad
No full textAnalisi delle principali ricerche svolte da Khalid al-As'ad a Palmira, nella seconda metà del Novecento
Electric-Magnetic Uniaxial Lossy Medium and its Applications to Boundary Conditions and Metamaterials
No full textIn this dissertation, properties of a general electric-magnetic uniaxial lossy medium and its applications to boundary conditions and metamaterials are investigated. In the first part of the dissertation, electromagnetic reflection from the interface of an electric-magnetic uniaxial lossy medium is studied. It is assumed that the uniaxial medium is characterized by complex permittivity and permeability tensors, and has an arbitrarily directed optic axis. The propagation of both homogeneous and inhomogeneous waves in the uniaxial lossy medium is discussed. Many metamaterials proposed in literature can be homogenized as electric-magnetic uniaxial media. We investigate their characteristics and try to understand their limitations due to presence of the material losses. The interface of the uniaxial medium with a simple isotropic medium is analyzed by applying the general soft-and-hard and DB boundary conditions. The reflection is investigated under different circumstances by considering various orientations of the plane of incidence with respect to the plane containing the optic axis of the medium. The results obtained in the lossy case are compared with those of lossless one, available in the literature.
Subsequently, we present a reflection analysis of a plane wave striking on an interface of a novel uniaxial medium characterized by extreme constitutive parameters: very large transverse and very small longitudinal components of the diagonal permittivity and permeability tensors. The novelty of the medium is specified by enforcing particular conditions on the material properties. The reflection is studied by assuming that the optic axis of the uniaxial material is arbitrarily oriented. We discuss the effect of the direction of the optic axis on the reflection characteristics and emphasize on its importance for the realization of electromagnetic absorbers. The behavior of the medium is also examined by varying the direction of the plane of incidence with respect to the plane of the optic axis. It is observed that, in this case, there exists a Brewster-like angle where the interface activates zero reflection for the co-component of the incident field while total reflection for the cross-component. An analytical expression for this angle is also presented. From the numerical results it is noticed that the medium shows very interesting properties of behaving as a perfect reflector, a perfect transmitter and a polarization inverter depending upon the direction of the optic axis and the plane of incidence.
The second part of the thesis focuses on a numerical analysis of the three-dimensional unit-cell structure proposed for practical realization of the metamaterial, satisfying the DB boundary conditions. The realization of the DB boundary conditions require cancellation of the normal components of electric flux density vector \textbf{D} and magnetic flux density vector \textbf{B} on the boundary surface. The cancellation of these components happens if the components of both permittivity and permeability orthogonal to the interface are zero. We present free-space computer simulation results for the unit-cell structure consisting of two circular split-ring resonators and a metallic wire immersed in an ordinary dielectric medium. Moreover, a new composite design based on rectangular split-ring resonators which can imitate the DB behavior is also presented. From numerically calculated reflection and transmission parameters all components of the effective permittivity and permeability tensors, characterizing the DB material, are retrieved both in the axial as well as in the orthogonal directions to the metamaterial boundary. Such effective constitutive parameters are extracted using the scattering parameters inversion technique for a plane wave obliquely incident on a metamaterial slab
Report on Ideas and Work and Legacy of Islamic thinker Khalid Muhammad Khalid
No full textتقرير حول عطاء و أعمال و أفكار المفكر الإسلامي خالد محمد خالد بعد رحيله. جائت بهذا التقرير إيمان رافع.A report on the ideas and work and legacy of Islamic thinker Khalid Muhammad Khalid after his passing. Report by Iman Rafi
Enhancing second-harmonic generation with electron spill-out at metallic surfaces
Full text linkSecond-order nonlinear optical processes do not manifest in the bulk of centrosymmetric materials, but may occur in the angstroms-thick layer at surfaces. At such length scales, quantum mechanical effects come into play which could be crucial for an accurate description of plasmonic systems. In this article, we develop a theoretical model based on the quantum hydrodynamic description to study free-electron nonlinear dynamics in plasmonic systems. Our model predicts strong resonances induced by the spill-out of electron density at the metal surface. We show that these resonances can boost second-harmonic generation efficiency up to four orders of magnitude and can be arbitrarily tuned by controlling the electron spill-out at the metal surface with the aid of thin dielectric layers. These results offer a possibility to artificially increase nonlinear susceptibilities by engineering optical properties at the quantum level
Hybrid Rigid–Soft Industrial Gripper: Actuation, Design Enhancement, Multi-Modal Sensorization, and Real-Time Coordinated Control for Automotive Assembly
No full textThe growing complexity of industrial automation and the shift toward human–robot collaborative manufacturing demand robotic grippers that combine mechanical precision, adaptive compliance, and intelligent sensing. This doctoral thesis addresses these needs through comprehensive research on actuation mechanisms, kinematic analysis, design enhancement, advanced sensorization, and industrial implementation of a versatile universal gripper system capable of handling components from delicate items to complex rigid parts. In parallel, it contributes to industrial robot control within the EU Horizon SESTOSENSO project.
The work begins with a detailed kinematic analysis of a novel three-finger gripper architecture. Each rigid mechanical finger integrates a Chebyshev–parallelogram linkage mechanism with a thermoplastic polyurethane (TPU) contact interface. The mechanism produces near-linear trajectories with a deviation of ±0.033 mm and a mechanical advantage of 6.06:1. Independent actuation is achieved using JVL stepper motors with embedded programmable logic controllers (PLCs), communicating via Modbus remote terminal unit (RTU). The control architecture supports torque-based and velocity-based stall detection, both operating in real time with configurable thresholds. These strategies enable reliable grasping without dedicated force sensors by leveraging internal motor feedback parameters.
Gripper enhancement is guided by a quantitative deflection coefficient to assess finger wrapping and by quasi-static force–displacement testing. The original four-bar parallelogram was redesigned into a six-bar linkage with compliant pads. This eliminates link interference limitations while preserving the essential kinematics, resulting in adaptive grasping capability. Pull-out tests demonstrated improved force profiles for complex automotive parts and reliable manipulation of objects from 100 g to 7.5 kg.
Vision-based sensorization was achieved through an embedded Raspberry Pi Camera V3.
The integration of vision-based sensing within the additively manufactured soft finger structure establishes the feasibility of achieving multiple sensing modalities with a single compact embedded system while retaining the characteristic properties of the fingers. The proposed system successfully estimates normal interaction forces, measures internal deformation (Z-displacement), classifies the position of the applied force, and detects slip events with the complete sensing pipeline processed on an embedded platform while avoiding complex signal disambiguation challenges and occlusion issues. Complementing this, a fully flexible resistive sensor was fabricated via fused deposition modeling (FDM) printing and embedded in the finger for contact and bending detection. A novel light-angle sensor array was also developed using a custom four-layer rigid-flex printed circuit board (PCB), where prototype sensors successfully demonstrate distributed tactile sensing capabilities.
The universal gripper and sensing systems were validated on a COMAU six-degrees-of-freedom (6-DOF) industrial robot in diverse grasping trials, confirming adaptability, robustness, and sensing reliability. Separately, within the SESTOSENSO project, real-time control strategies were developed for coordinating a KUKA KR150 robot with a UR10 cobot via robot sensor interface (RSI) and robot operating system (ROS) in an automotive roof assembly task. This work addressed control architecture, real-time trajectory correction, and safe human–robot collaboration in confined, visually occluded environments.
This thesis advances the state of the art in hybrid gripper systems by integrating rigid precision, soft adaptability, and intelligent sensing with industrially validated control strategies. The outcomes directly support Industry 4.0/5.0 objectives, enabling flexible, high-performance automation adaptable to diverse manufacturing requirements
Numerical study of spherical nanomatryoshkas by using quantum hydrodynamic theory (Conference Presentation)
No full textUsman Khalid, Muhammad Shafiullah, Sajid M. Chaudhry: Súlyosbítja-e a konfliktus az energiaszegénységet?3
Full text linkSzerzők és a kutatás célja
A tanulmányt az Egyesült Arab Emírségek Egyetemén, a Bangladesi Brac Egyetemen, valamint az egyesült királyságbeli Aston Business Schoolban, a gazdaságtan és pénzügy
területén dolgozó Usman Khalid, Muhammad Shafiullah és Sajid M. Chaudhry készítette.
A cikk fő célja, hogy megvizsgálja a belső konfliktusok és az energiaszegénység közötti kapcsolatot, különös tekintettel arra, hogy a belső menekültek helyzete milyen hatással van az energiaellátásra
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