7,563 research outputs found

    Exchange bias effect in the phase separated Nd_{1-x}Sr_{x}CoO_3 at the spontaneous ferromagnetic/ferrimagnetic interface

    Full text link
    We report the new results of exchange bias effect in Nd_{1-x}Sr_{x}CoO_3 for x = 0.20 and 0.40, where the exchange bias phenomenon is involved with the ferrimagnetic (FI) state in a spontaneously phase separated system. The zero-field cooled magnetization exhibits the FI (T_{FI}) and ferromagnetic (T_C) transitions at ~ 23 and \sim 70 K, respectively for x = 0.20. The negative horizontal and positive vertical shifts of the magnetic hysteresis loops are observed when the system is cooled through T_{FI} in presence of a positive static magnetic field. Training effect is observed for x = 0.20, which could be interpreted by a spin configurational relaxation model. The unidirectional shifts of the hysteresis loops as a function of temperature exhibit the absence of exchange bias above T_{FI} for x = 0.20. The analysis of the cooling field dependence of exchange bias field and magnetization indicates that the ferromagnetic (FM) clusters consist of single magnetic domain with average size around \sim 20 and ~ 40 \AA ~ for x = 0.20 and 0.40, respectively. The sizes of the FM clusters are close to the percolation threshold for x = 0.20, which grow and coalesce to form the bigger size for x = 0.40 resulting in a weak exchange bias effect.Comment: 9 pages, 9 figure

    On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films

    Full text link
    The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO_{2} films was observed to increase systematically while that for SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO_{2} while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed modifications in the optical properties of both the TiO_{2} and the SnO_{2} systems with irradiation can be attributed to controlled structural disorder/defects in the system.Comment: 6 pages, ICAMD-201

    DEM simulation of effect of confining pressure on ballast behaviour

    Get PDF
    In this paper, an attempt has been made to investigate the influence of confining pressure on deformation and degradation behaviourof railway ballast using the Discrete Element Method (DEM). A novel approach has been employed to model the two dimensionalprojection of field size ballast particles as cluster of bonded particles. Bonded particles are held together by a bond, and debonding isconsidered as particle breakage. A series of cyclic loading simulations using DEM were carried out on an assembly of angular ballast particles at different confining pressures (10 kPa to 240 kPa). The results highlight that the development of axial strain during cyclicloading as a function of initial confining pressure and number of cycles. Very high axial strain and breakage of particles have been observed at low confining pressure (\u3c 30 kPa) owing to dilative volumetric strain behaviour. In terms of particle breakage, there existsan optimum range of confining pressures where breakage is minimal. In addition, the evolution of particle displacement vectors explains the breakage mechanism and associated deformations during cyclic loading

    6-[(Dimethyl­amino)methyl­ene­amino]-1,3-dimethyl­pyrimidine-2,4(1H,3H)-dione dihydrate

    Get PDF
    Uracil, the pyrimidine nucleobase, which combined with adenine forms one of the major motifs present in the biopolymer RNA, is also involved in the self-assembly of RNA. In the title compound, C9H14N4O2·2H2O, the asymmetric unit contains one dimethyl­amino­uracil group and two water mol­ecules. The plane of the N=C—NMe2 side chain is inclined at 27.6 (5)° to the plane of the uracil ring. Both water mol­ecules form O—H⋯O hydrogen bonds with the carbonyl O atoms of the uracil group. Additional water–water hydrogen-bond inter­actions are also observed in the crystal structure. The O—H⋯O hydrogen bonds lead to the formation of a two-dimensional hydrogen-bonded network cage consisting of two dimethyl­amino­uracil groups and six water mol­ecules

    The Integration of Lean and Human Resource Management Practices as an Enabler for Lean Deployment- A Systematic Literature Review

    Get PDF
    Purpose – The current research aims to map and investigate how Human Resource Management and Lean practices can be integrated. This investigation will help identify the Human Resource Management aspects critical in the success of Lean initiatives while exploring the research gaps in the existing literature. The review also aims to delineate the benefits and challenges of integrating Lean with Human Resource Management systems to discuss further research and practice areas. Design/methodology/approach – This study utilizes a Systematic Literature Review method to identify and synthesize the existing literature. As part of the process, a protocol that provided a plan for the review was followed, including the research questions and the data to be extracted. Findings– The study results indicate that aspects of Human Resources Management practice and policies such as Training & Development, Teamwork, Motivation, Communication, Leadership, are key enablers of Lean initiative deployment and success. The benefits of the integration of Human Resources with Lean 15 can help in Lean training and development, communication of Lean initiatives and successes, allocating and hiring continuous improvement personnel, and supporting leadership in Lean deployment. Challenges to integrating Lean and HRM practices included lack of integration and collaboration between disciplines. Further exploration areas in successful Lean deployment would be practical longitudinal case studies on Lean deployments with HR partnerships and involvement. Practical implications – This review paper has crucial implications for practice relating to, integration of Lean with Human resource management structures and tailoring Human resource management initiatives to ensure the success of Lean deployment and reduce risks of failure. Originality/value – The Systematic literature review study conducted in this paper is the first of its kind to integrate and map the human resource management concepts that can be integrated with Lean to deploy the initiative successfully. This mapping is critical for ensuring the success of Lean methodologies within an organization and paves the way for future research. In addition, managers and organizations can find support and guidance from this study to focus on vital areas of partnership between their Lean and HR programs

    Low temperature specific heat of La_{3}Pd_{4}Ge_{4} with U_{3}Ni_{4}Si_{4}-type structure

    Full text link
    Low temperature specific heat has been investigated in a novel ternary superconductor La_{3}Pd_{4}Ge_{4} with an U_{3}Ni_{4}Si_{4}-type structure consisting of the alternating BaAl_{4} (ThCr_{2}Si_{2})- and AlB2_{2}-type layers. A comparative study with the related ThCr_{2}Si_{2}-type superconductor LaPd_{2}Ge_{2}, one of the layers in La_{3}Pd_{4}Ge_{4}, is also presented. From the normal state specific heat, the Sommerfeld coefficient γn=27.0\gamma_{n} = 27.0 mJ/mol K^2 and the Debye temperature ΘD\Theta_{\rm D} = 256 K are derived for the La_{3}Pd_{4}Ge_{4}, while those for the LaPd_{2}Ge_{2} are γn=8.26\gamma_{n} =8.26 mJ/mol K^2 and ΘD\Theta_{\rm D} = 291 K. The La_{3}Pd_{4}Ge_{4} has moderately high electronic density of state at the Fermi level. Electronic contribution on the specific heat, CelC_{\rm el}, in each compound is well described by the BCS behavior, suggesting that both of the La_{3}Pd_{4}Ge_{4} and the LaPd_{2}Ge_{2} have fully opened isotropic gap in the superconducting state

    Manufacturing and characterization of sustainable and recyclable wood-polypropylene biocomposites:Multiprocessing-properties-structure relationships

    Get PDF
    In this study, sustainable polymeric materials with a polypropylene matrix reinforced with wood waste were developed for structural applications. The new polymer biocomposites (WPCs) were evaluated for their mechanical and structural properties regarding their susceptibility to multiple processing. As thermo-mechanical degradation processes are associated with the repeated processing of plastics, which causes changes in the properties and structure of these materials. Therefore, to determine the extent to which the composites can be used under operating conditions, the composites were examined by DMA. As a result of the study observed some effects caused by the repeated effects of shear stress and temperature on the rheological and mechanical properties of polymer composites. The first of these is related to a decrease in viscosity of WPC composites subjected to the six times processing and changes in flow conditions during extrusion and injection moulding due to the degradation of the polypropylene matrix. As the viscosity of the composites decreased, a reduction in tensile strength and other mechanical properties of the polypropylene matrix was noted. On the other hand, the second effect observed leads to the conclusion that, as the composites' processing cycles increase, the WPC composite's mechanical properties increase due to an increase in the degree of homogenization of the individual components of the WPC composition. This study aims to describe the relationship between these two primary processes and to determine the relationship between the properties and the structure of the new WPCs.</p

    Exploring metastability via the third harmonic measurements in single crystals of 2H2H-NbSe2NbSe_2 showing anomalous Peak effect

    Get PDF
    We explore the metastability effects across the order-disorder transition pertaining to the peak effect phenomenonon in critical current density (JcJ_c) via the first and the third harmonic ac susceptibility measurements in the weakly pinned single crystals of 2H2H-NbSe2NbSe_2. An analysis of our data suggests that an imprint of the limiting (spinodal) temperature above which JcJ_c is path independent can be conveniently located in the third harmonic data (χ3ω′\chi_{3\omega}^{\prime}).Comment: Accepted for publication in Phys. Rev.
    • …
    corecore