Autor: Rashid, M. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Cover of Cylinder Lattice Plastic Convert into Fuel
Autorzy:: Sarker, M.
Rashid, M. M.
Tematy:: plastic lattice
conversion
fuel
hydrocarbon
waste plastics material
GC-MS; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/412122.pdf Link otwiera się w nowym oknie
Opis:: Waste plastic of cylinder lattice to liquid fuel production process was performing two step processes. 1st step process was perform muffle furnace with ceramic crucible and 2nd step process was perform glass reactor with condensation unit. Thermal degradation process was performing with furnace and temperature was 410 ?C and reactor temperature was 420 ?C. Muffle furnace was use for solid hard shape of plastic melting purpose and glass reactor was use for liquid slurry to produce vapor purpose. Liquid slurry to produce vapor was condensed and collected liquid fuel and fuel density is 0.75 g/ml. Liquid fuel production conversation rate was 71.05 %. Fuel was analysis by GC/MS and carbon chains obtain C3 to C23 from GC/MS chromatogram. Fuel color is light yellow and fuel is ignited.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: On Theoretical Study of Magnetic Behavior of Diamond Doped with Transition Metals
Autorzy:: Hussain, F.
Ullah, M.
Ullah, H.
Rashid, M.
Imran, M.
Ahmad, E.
Tematy:: 75.10.Kt
75.10.Pq
75.30.Hx; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1399279.pdf Link otwiera się w nowym oknie
Opis:: We study the magnetic behavior of the diamond system. In this system diamond bulk is involved which is doped with different transition metals, namely Cu, Cd, Hg, and Zn. The VASP code is employed for all calculations which are based on density functional theory. The substitutional point defects is introduced in the diamond bulk and occupied by the transition metals. Results exhibit that all transition metals show ferromagnetism behavior and Cu is a good advocate of conductivity among all transition metals. The range of magnetic moments is 2.89, 1.99, 1.96, and 1.80 $μ_{B}$ per Cu, Cd, Hg, and Zn atom in diamond bulk, respectively. Strong magnetic behavior points out that these materials could be used for spintronics.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Improving machining performance against regenerative tool chatter through adaptive normal pressure at the tool clamping interface
Autorzy:: Fu, Q.
Rashid, A.
Nicolescu, C. M.
Tematy:: chatter
tool
internal turning
vibration
clamping
damping
interface; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/99845.pdf Link otwiera się w nowym oknie
Opis:: Chatter in machining process is one of the common failures of a production line. For a cantilever tool, such as a boring bar, the rule of thumb requires the overhang length of the tool to be less than 4 times the diameter. The reason is because longer overhang will induce severe tool vibration in the form of chatter during machining. When a longer overhang than 4 times diameter is necessary for performing special machining operations, damping methods are needed to suppress tool chatter. One of the methods is the constrained layer damping method. Materials, such viscoelastic material, are applied in the vibration node regions of the structure to absorb the concentrated vibration strain energy and transform the mechanical energy to heat. With a cantilever tool clamped in a tool holder, the clamping interface is usually the vibration node region. The friction in the joint interface with low normal pressure became another source of damping and can be used for tool chatter suppression in mechanical structures. Joint interfaces are well known to possess normal pressure dependent stiffness and damping. The normal pressure's effect on the structures frequency response function had been observed by H. Akesson [1] et al, and L.Mi [2] et al. However, the direct effect of the joint interface normal pressure on machining process stability hasn't been investigated. In this paper, a cantilever tool with 6,5 overhang length to diameter ratio is investigated. The direct effect of the tool clamping interface's normal pressure on the machining process stability is studied. Three different levels of clamping normal pressure are tested with an internal turning process. The machining results indicate another adaptable solution on shop floor for suppressing tool chatter.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Experimental analysis of a machining system with adaptive dynamic stiffness
Autorzy:: Frangoudis, C.
Nicolescu, C. M.
Rashid, A.
Tematy:: vibrations
milling
damping
stiffness
adaptive structure; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/100189.pdf Link otwiera się w nowym oknie
Opis:: A main consideration in the operation of machine tools is vibrations occurring during the cutting process. Whether they are forced vibrations or self-excited ones, they have pronounced effects on surface quality, tool life and material removal rate. This work is an experimental study of interactions between natural characteristics, control parameters and process parameters of a machining system designed with adaptive dynamic stiffness. In order to comprehend these interactions, the effect of changes in dynamic stiffness on the system's response is examined. The system under study consists of an end-milling tool, a steel workpiece and a work holding device with controllable stiffness. Natural dynamic characteristics of the system components are determined through modal impact testing. Then the behaviour of the whole machining system is examined under both high and low cutting speed conditions by analysing vibration levels using acceleration signals acquired through a tri-axial sensor mounted on the workpiece. Cutting is performed in both directions of the horizontal plane of a CNC milling machine. In both cases the results are presented for two extremes of stiffness and damping in the work holding device. The effect of control parameters on the system's natural characteristics could be identified together with a relation between these parameters and the system's response in high and low cutting speed conditions. The high-damping configuration reduces the vibration amplitudes significantly, while the increase of pre-stress has a different effect depending on the cutting conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Study the internal cracks effect on vibration of laminated composite square plates
Autorzy:: Hassan, M.S.
Rashid, Z.H.
Sarhan, R.A.
Tematy:: laminate plate
natural frequency
boundary condition
cracked plate
finite element
ANSYS
płyta laminowana
częstotliwość drgań własnych
warunek brzegowy
pęknięta płyta
element skończony; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/24200571.pdf Link otwiera się w nowym oknie
Opis:: Purpose: The study of cracks behaviour in a composite plate is of significant importance in the dynamics of the Mechanical parts in order to avoid design failures due to resonance or high amplitude vibrations. Design/methodology/approach: In this paper, a square glass-epoxy composite plate is adopted. The plate has four layers with symmetric and asymmetric lamination. Assuming the cracks are profound as defects. The results were obtained by using a numerical solution of mechanical APDL from ANSYS. Findings: It has been found for different boundary conditions that the rank of natural frequencies is decreased by increasing the crack ratio due to the reduction of the plate’s stiffness, whereas the crack direction has no mentioned effect for a small angle of rotation. Research limitations/implications: The accuracy of results is verified by comparing a single case of the current work with other previous investigations. value: Evaluate the influence of the crack length ratio, angle of the crack rotation, boundary conditions and lamination angles on the natural frequencies of the square composite plate with glass-epoxy materials.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Active alignment chuck for ultra-precision machining
Autorzy:: Daghini, L.
Archenti, A.
Rashid, A.
Nicolescu, C. M.
Tematy:: ultraprecision machining
high damping interface
active alignment; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/99849.pdf Link otwiera się w nowym oknie
Opis:: Ultraprecision (UP) components have become common in everyday life products such as mobile phones or compact high resolution digital cameras. Thus the need of producing such components with high accuracy and low production cost. UP machine tools are capable of extremely high accuracy in tool positioning but still today the workpiece is positioned by hand, hence the high production cost of UP components. A fully automated chain of production has been developed within the EU-IP project "Production 4 micro". This paper describes the active alignment chuck for workholding in UP machining. The chuck has been provided with a high damping interface (HDI) and to evaluate its efficiency the chuck has undergone an experimenta modal analysis (EMA) as well as machining tests. The chosen operation was grooving by fly cutting using a diamond tool. The EMA showed that the HDI was effective for those modes where there was relative displacement between one side and the other of the HDI. This result was confirmed by the machining tests as well. The HDI resulted being effective in damping high frequency modes (around 4 - 5 kHz), hence one expected benefit would be a longer tool life.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Preconditiong and Inoculation of Low Sulphur Grey Iron
Autorzy:: Hossain, Md Sojib S.
Bazlur B. Rashid, A. K. M.
Tematy:: grey iron
metallography
mechanical properties
cementite
preconditioner
inoculant
żeliwo szare
metalografia
właściwości mechaniczne
cementyt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/380548.pdf Link otwiera się w nowym oknie
Opis:: For quality grey cast iron production, the challenging issues are to avoid cementite structure and obtain the desired graphite morphology with proper matrix as well as hardness. The objective of the present research is to find out the right combination of preconditioner and inoculant that may help to overcome the challenges. In this work, sulphur content is kept low (0.01%). Two preconditioners namely metallurgical SiC and zirconium bearing FeSi with two types of inoculant are individually used to make four combinations of sample and for each case metal is poured into the green sand mould. Finally Brinell hardness and graphite morphology is observed in the thickest and thinnest portions of the castings. Metallurgical SiC with barium bearing inoculant gives better graphite morphology and hardness than strontium bearing inoculant, on the other hand zirconium bearing FeSi gives more satisfying result than SiC with every type of inoculant. Among all of the combinations Zr bearing preconditioner with Ba bearing inoculant gives good graphite morphology with best mechanical properties in both thickest and thinnest portions of the casting.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: New Paradigm in Control of Machining Systems Dynamics
Autorzy:: Nicolescu, M.
Frangoudis, C.
Semere, D.
Archenti, A.
Rashid, A.
Tematy:: machining system
parametric identification
operational dynamic parameters
joint interface module; Pokaż więcej
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Powiązania:: https://bibliotekanauki.pl/articles/99497.pdf Link otwiera się w nowym oknie
Opis:: The increasing demands for precision and efficiency in machining call for effective control strategies based on the identification of static and dynamic characteristics under operational conditions. The capability of a machining system is significantly determined by its static and dynamic stiffness. The aim of this paper is to introduce novel concepts and methods regarding identification and control of a machining system’s dynamics. After discussing the limitations in current methods and technologies of machining systems’ identification and control, the paper introduces a new paradigm for controlling the machining system dynamics based on design of controllable structural Joint Interface Modules, JIMs, whose interface characteristics can be tuned using embedded actuators. Results from the laboratory and industrial implementation demonstrate the effectiveness of the control strategy with a high degree of repeatability.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Demographic dividend in Saudi Arabia: From age structural changes to economic gains
Autorzy:: Al-Khraif, Rshood M.
Abdul Salam, Asharaf
Abdul Rashid, Mohd Fadzil
Tematy:: Accounting effect
Age-sex structure
Demographic transition
Labor force
Median age; Pokaż więcej
Wydawca:: Uniwersytet Ekonomiczny w Katowicach
Powiązania:: https://bibliotekanauki.pl/articles/2028390.pdf Link otwiera się w nowym oknie
Opis:: Aim/purpose – The demographic dividend, defined as the proportion of working age to the rest of the population, is an opportunity seen mainly in developing countries, resulting from demographic transition. Efforts to maximize gains from it are crucial, especially for the Arabian Gulf states, where labor force demands are met at the danger of native youth unemployment that leads to issues of human resources utilization. This research on Saudi Arabian demographic dividend aims at tracking changes in the age structure, labor force participation, and prospects leading to economic gains. Design/methodology/approach – Data from various sources such as censuses (1974, 1992, 2004, and 2010), national labor force surveys 1999-2017 and United Nations (UN) Population Prospects are compiled and statistically analyzed with a historical approach for calculations of age distribution, median age, and labor force participation adopting standard procedures. Findings – An age structural transition occurred: percentage of population 15-64 years increased from 47.2% to 67.3%, increasing the dividend from 89.6% to 205.5%. This influenced the labor force’s sectoral distribution, and Gross Domestic Product (GDP) per working age population. Research implications/limitations – The dividend’s first phase, since 2000, is expected to last until 2050, followed by the second dividend which may last longer. Along with the dividend, there shall be policies executed to reap the benefits, including scientifically planned recruitment of potential candidates in various professions, both in public and private sectors. Originality/value/contribution – This research concerns a population, which is unexplored in detail, especially at a macro level. Thus, such an in-depth analysis seeks importance in revealing special demographic dimensions to a wider international audience. There are no such studies conducted in Saudi Arabia, with a national perspective helpful for revamping efforts to boost labor force reforms and to make maximum gain during the short-lived demographic dividend period.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Analytical analysis of thermal conductivity by laminar flow under the influence of mhd using Vogel’s model
Autorzy:: Nawaz, Rashid
Farooq, Muhammad
Rehman, Siddiq Ur
Ismail, Gamal M.
Ahmad, Hijaz
Tematy:: OHAM
HPM
couple stress fluid
magnetohydrodynamics
Vogel’s model; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/58907239.pdf Link otwiera się w nowym oknie
Opis:: The main aim of this work is to study the influence of thermal conductivity of uniform couple stress fluid of inclined Poiseuille flow in the presence of magneto hydrodynamic (MHD) between two parallel plates. A well-known Vogel’s viscosity model is used. The momentum and energy equations are solved analytically by utilizing Homotopy Perturbation method (HPM) and Optimal Homotopy Asymptotic Method (OHAM). The results include the velocity profile, average velocity, volume flux, Shear Stress, Skin friction and the temperature distribution between the plates. Particular attention is given to the effect of MHD Γ on the velocity field and temperature distribution. As can be seen, that there exists direct relation between MHD parameter Γ and velocity profile and bears inverse relation with temperature distribution. In addition to that, influence of non-dimensional parameters like G, A, a, B and γ on the velocity field and temperature distribution are also discussed graphically. The physical characteristics of the problem have been well discussed in graphs for several parameters of interest. The results reveal that both techniques are reliable and are in great agreement with each other.
Dostawca treści:: Biblioteka Nauki

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