Critical Analysis of Problems of School Teachers in Pakistan: Challenges and Possible Solutions

The education system of Pakistan, in terms of quality teaching and learning, stands in the lowest rank in the world. Numerous reasons can be held responsible for this state of affairs. Teacher is one of these factors. Teacher is an important part of the teaching and learning process, who faces various problems due to which they cannot play their roles effectively in the education process. This paper, based on a thorough review of the existing literature, critically analyses the problems faced by school teachers in the Khyber-Pakhtunkhwa province of Pakistan. Findings of the study revealed that teachers are less motivated towards teaching profession, because  their appointments, transfers, placements and promotions are decided on nepotism, corruption and political affiliations rather than on merit. In many cases teachers are posted in remote areas, faced with accommodation and transportation problems. The study further found that teachers are overburdened with more classes due to shortage of staff in schools, teachers face shortage of teaching and learning resources in schools, there are fewer professional development opportunities for teachers, servant-master environment and a culture of leg-pulling and flattering prevails in schools, and that teachers often rely on other activities such as property business, shop-keeping etc for living. This has gravely affected the process of teaching and learning in schools. This study recommends that the problems of teachers could be solved by creating an environment of trust and strengthening the mechanism of accountability, providing teaching and learning resources to schools, providing ongoing professional development opportunities and incentives to teachers, making appointments and promotions on merit,  providing enough staff to schools and eradicating the evil of political interference. Keywords: education, problems of teachers, critical analysis, possible solutions, quality of teaching and learnin

Degradation assessment of nuclear power plant extraction steam piping after long term service

Degradation due to ageing in a Nuclear Power Plant’s Extraction Steam Piping has been assessed. Samples of twelve years old seamless carbon steel SA 106B pipe have been taken and subjected to metallographic examination, hardness testing, radiographic examination and ultrasonic thickness measurement to investigate and analyze ageing in piping material. Metallographic examination of aged sample revealed irregularly distributed graphite nodules in ferrite grains and on grain boundaries as well, the reduction in pearlite phase has also been observed from 40% to 25%. This Transformation in microstructure has reduced hardness of steel. Reduction in hardness has found 20.4% and 0.7% on inner and outer layer of the pipe material respectively. Corrosion pits having average depth of 0.07 mm have been found on external surface. Radiograph of aged pipe revealed material removal and wall thinning due to erosion on inner surface of pipe. The extent of erosion had been checked, which has found 8.7%

Augmentation of Fatigue and Tensile Strength of AA-6061 Processed through Equal Channel Angular Pressing

ECAP (Equal Channel Angular Pressing) is a technique used to enhance the strength of material by grain refinement. In this research, an aerospace grade aluminum alloy-6061 is investigated. The specimens were pressed through ECAP die channels, intersecting each other at an angle of 90oC where a shear plane of 45oC was developed, that results grains refinement. Fatigue strengths and CGR (Crack Growth Rate) for the stress ratio R 0.7 and 0.1 are found and compared with the as-received material.It was observed that the CGR is slower at stress ratio R=0.1, as compared to stress ration R=0.7. An electric furnace was embedded with ECAP die to regulate the material flow through this die. The temperature of the die was maintained at 450oC during ECAP pressing and the specimens were also preheated at this temperature using another furnace. The ECAP die consistsof two channels intersecting at 90o provided with safe inner and outer corner radius to avoid scaling.The microstructural observations revealed that the deformation was perfectly plastic. The ECAPed and as-received materials were also characterized by tensile tests, micro-hardness tests, and 3-point bend fatigue tests

Application of sayong ball clay membrane filtration for Ni (II) removal from industrial wastewater

Wastewater containing heavy metals, such as nickel ions (Ni2+), discharged from industry to water streams poses a serious threat because even at low concentrations, it does not naturally degrade and is toxic to human and aquatic life. This article reviews a novel technique for wastewater treatment using a Sayong ball clay (SBC) membrane to remove nickel from industrial waste water. SBC powder was achieved through milling using a planetary ball mill (milling time; 10, 20 and 30 h), further labelled as SBC 10, SBC 20 and SBC 30, with a ball-to-powder of ratio 7: 1 and rotation speed of 300 rpm. The physical characteristics of the apparent porosities, bulk density and shrinkage were investigated. XRD was used to study the phase, while FESEM was used to analysethe microstructure of the fired membrane. The FESEM microstructure indicates a decreased particle size (SB30). Filtration was conducted using a dead-end filtration system. The fabricated SBC 10, 20 and 30 membranes showed significant removal of nickelfrom industrial wastewater-88.87%, 82.96% and 85.13%, respectively. This study revealed that the SBC membrane is a promising membrane to remove nickel from industrial wastewater. The results also indicate the possibility of highlighting the introduced technique as a new technique for the treatment of industrial wastewater. As a new trend for waste management, pollution prevention could be applied in Malaysia as one of the advanced biotechnologies to solve various environmental problems

Siting Consideration for Nuclear Power Plant: A Review

The purpose of this research is to study in detail about the site selection process in nuclear power plant (NPP) construction. There are various factors that contribute to the site selection which involves in-depth investigation and detailed evaluation before the site is being finalized and proposed. There are two main objectives in siting of NPP; ensuring the technical and economic feasibility of the plant and minimising potential adverse impacts on the community and environment. Geographical environment also plays an important role in siting of NPP where the source of water should be abundance. Country requirement for siting of NPP would be different for every country where they are controlled by their own regulatory bodies. About 64 published studies (1967-2017) are reviewed in this paper. It is marked from the literature survey articles that siting process is extremely crucial step in constructing NPP where public acceptance is one of the main factors, that need to be considered. Malaysia is one of the new countries embark in nuclear industry that still is in the planning phase to plan and construct its first NPP

Neuroprotective Effect of Quercetin Against the Detrimental Effects of LPS in the Adult Mouse Brain

Chronic neuroinflammation is responsible for multiple neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. Lipopolysaccharide (LPS) is an essential component of the gram-negative bacterial cell wall and acts as a potent stimulator of neuroinflammation that mediates neurodegeneration. Quercetin is a natural flavonoid that is abundantly found in fruits and vegetables and has been shown to possess multiple forms of desirable biological activity including anti-inflammatory and antioxidant properties. This study aimed to evaluate the neuroprotective effect of quercetin against the detrimental effects of LPS, such as neuroinflammation-mediated neurodegeneration and synaptic/memory dysfunction, in adult mice. LPS [0.25 mg/kg/day, intraperitoneally (I.P.) injections for 1 week]-induced glial activation causes the secretion of cytokines/chemokines and other inflammatory mediators, which further activate the mitochondrial apoptotic pathway and neuronal degeneration. Compared to LPS alone, quercetin (30 mg/kg/day, I.P.) for 2 weeks (1 week prior to the LPS and 1 week cotreated with LPS) significantly reduced activated gliosis and various inflammatory markers and prevented neuroinflammation in the cortex and hippocampus of adult mice. Furthermore, quercetin rescued the mitochondrial apoptotic pathway and neuronal degeneration by regulating Bax/Bcl2, and decreasing activated cytochrome c, caspase-3 activity and cleaving PARP-1 in the cortical and hippocampal regions of the mouse brain. The quercetin treatment significantly reversed the LPS-induced synaptic loss in the cortex and hippocampus of the adult mouse brain and improved the memory performance of the LPS-treated mice. In summary, our results demonstrate that natural flavonoids such as quercetin can be beneficial against LPS-induced neurotoxicity in adult mice

Identification of vibration and elastic properties of aluminum foam using modal testing and analysis

Zsfassung in dt. SpracheGeschäumtes Aluminium wird zunehmend als Alternative für herkömmliche Materialien eingesetzt, vor allem wegen der hohen Festigkeit, spezifischen Steifigkeit, geringen Masse sowie der anpassbaren Eigenschaften. Bevor jedoch dieses vielversprechende Material in industriellen Anwendungen eingesetzt werden kann, ist eine vollständige Charakterisierung der Materialeigenschaften erforderlich.Aufgrund der Vielzahl und der damit einhergehenden Variabilität der Materialeigenschaften von Aluminium Schaumstoffen ist eine experimentelle Charakterisierung sehr aufwändig, da entsprechend viele Proben untersucht werden müssten. Dieser Problematik kann durch den gemeinsamen Einsatz von numerischen und experimentellen Methoden, die in Kombination ein sehr leistungsfähiges Werkzeug für die Abschätzung unbekannter Materialkoeffizienten darstellen, entgegengewirkt werden. In dieser Arbeit wird eine Methode zur numerisch-experimentellen Identifikation, basierend auf der modalen Strukturantwort von Aluminiumschaum, vorgestellt. Dieses Verfahren basiert auf der Minimierung der Abweichungen der Eigenwerte und Eigenschwingungsformen zwischen einem numerischen Finite-Elemente-Modell und den entsprechenden experimentell ermittelten modalen Größen.Um eine möglichst hohe Qualität zur Identifikation der Materialparameter zu erreichen wird die experimentelle Bestimmung der modalen Parameter unter optimalen experimentellen Bedingungen durchgeführt. Die Proben, mit elastischen weichen Bändern aufgehängt, werden mit einem Shaker breitbandig angeregt, während die dynamische Strukturantwort mit einem Laser Scanning Vibrometer gemessen wird. Anschließend werden die erfassten Übertragungsfunktionen mit dem Modalanalyse Software-Paket LMS Test.Lab zu modalen Daten weiterverarbeitet.Da die Genauigkeit der Identifikation unmittelbar von der Präzision des FE-Modells abhängt, wurde zur Annäherung der Aluminiumschaumstruktur an eine kontinuierliche Größe ein spezielles Verfahren, die sogenannte Density Mapping Method, eingesetzt. Die Transformation von Aluminiumschaum, eine diskret heterogene Struktur, in eine annähernd homogene Struktur war eine der großen Herausforderungen. Die mikroskopische Dichteverteilung des Aluminiumschaums wurde mit Hilfe der Computer Tomographie erfasst, über bestimmte Bereiche gemittelt und als Eingangsgröße für das FE-Modell der entsprechenden Probe verwendet. Das elastische Verhalten wird durch das in das FE-Modell implementierte Gibson- und Ashby- Modell repräsentiert. Die numerische Modalanalyse erfolgt in ANSYS.Die Lösung des inversen Problems zur Bestimmung der grundlegenden elastischen Paremeter, die den experimentell ermittelten modalen Daten am besten entsprechen, wird nach dem nichtlinearen Levenberg-Marquardt Algorithmus zur Minimierung der kleinsten Fehlerquadrate ermittelt. Als Basis für den Vergleich zwischen den berechneten und den gemessenen Werten werden die relativen Unterschiede zwischen den Eigenfrequenzen, modale Dämpfung, Diagonal- und Nichtdiagonal-Termen hinsichtlich der modalen Qualitätssicherung sowie geometrische Eigenschaften der Schwingungsformen wie Knotenlinien verwendet. Der Ablauf der Identifizierung wird an Hand von Blockdiagrammen erläutert. Einige numerische Untersuchungen werden vorgestellt, um die variable Dichteverteilung hinsichtlich des modalen Verhaltens von Aluminium-Schaum zu prüfen.Das dynamische Verhalten von ALPORAS, ein Material mit geschlossenen Zellen, wurde experimentell und numerisch untersucht. Modale Untersuchungen von vier ALPORAS Proben zeigen, dass Inhomogenitäten in der Massenverteilung ein entscheidender Faktor bei der Beurteilung des dynamischen Verhaltens zellularer Werkstoffe sind. Eine umfassende Methode für die Identifizierung des dynamischen und elastischen Verhaltens zellularer Werkstoffe wurde vorgeschlagen. Im Rahmen der Werkstofftechnik, kann der vorliegende Ansatz für die Gestaltung von zellularen Werkstoffen sehr nützlich sein. Er ermöglicht die Vorhersage der besten Kombination aus mechanischen Eigenschaften des festen Materials und realisierbaren Mikrostrukturen, um die gewünschten mechanischen Eigenschaften zu erhalten.Aluminum foams are being increasingly used as alternatives for conventional materials primarily because of their high strength, specific stiffness, light weight, and adjustable properties. However, before using this type of material with confidence in industrial applications a thorough characterization of the material properties is needed. Because of the number and the inherent variability of the constitutive properties of aluminum foam materials, the experimental characterization is quite cumbersome and requires a large number of specimens to be tested. An elegant way to circumvent this lack consists in using mixed numerical-experimental methods which constitute a powerful tool for estimating unknown constitutive coefficients. In this work, a mixed numerical-experimental identification technique based on the modal response of aluminum foam is presented. This technique is based on the minimization of the discrepancies between the eigenvalues and eigen mode shapes computed with a finite element model and the corresponding experimental quantities.In order to maximize the quality of identification, optimal experimental conditions are selected for experimental determination of modal parameters. The specimens suspended by elastic soft bands are excited by a mini shaker, while the dynamic response is measured with a scanning laser vibrometer. The measured frequency response functions are then treated in modal analysis software package LMS Test.Lab to obtain modal data.As accuracy of the identification technique directly depends on precision of the finite element model, a special procedure called density mapping method, has been applied to approximate the aluminum foam structure with continuum. The transformation of a discretely heterogeneous structure of aluminum foam to an approximated continuum was one of the major challenges. The microscopical density distribution of aluminum foam recorded by X-ray computed tomography has been averaged over a certain domain and is used as input to the finite element model of corresponding specimen. Gibson and Ashby model is implemented in FE model to present the elastic behavior. Numerical modal analysis is performed in ANSYS.Levenberg-Marquardt nonlinear least squares minimization algorithm is used to solve the inverse problem of finding elastic constitutive parameters, which are best matching the experimental modal data. For comparing the computed and measured values, the implemented objective functions are based upon relative differences between the eigen frequencies, modal damping ratio, diagonal and off-diagonal terms of modal assurance criteria, and upon geometrical properties of the mode shapes such as nodal lines. The identification procedure is explained with the help of block diagrams. Some numerical investigations are presented to study the variable density distribution effect on modal behavior of aluminum foam.Dynamic behavior of closed cell material ALPORAS is investigated experimentally and numerically. Modal test on four ALPORAS specimens shows that inhomogeneties in the mass distribution are a key factor in evaluating dynamic behavior of cellular materials. A comprehensive methodology for the identification of dynamic and elastic behavior of cellular materials has been proposed. In the context of materials engineering, the present approach can be very useful for designing cellular materials. Indeed, it enables the prediction of best way of combining the mechanical properties of solid material with feasible microstructures, in order to obtain expected mechanical properties.<br /

Numerical Study on the Critical Frequency Response of Jet Engine Rotors for Blade-Off Conditions against Bird Strike

Vibrations are usually induced in aero engines under their normal operating conditions. Therefore, it is necessary to predict the critical frequencies of the rotating components carefully. Blade deformation of a jet engine under its normal operating conditions due to fatigue or bird strike is a realistic possibility. This puts the deformed blade as one of the major safety concerns in commercially operating civil aviation. A bird strike introduces unbalanced forces and non-linearities into the engine rotor system. Such dynamic behavior is a primary cause of catastrophic failures. The introduction of unbalanced forces due to a deformed blade, as a result of a bird strike, can change the critical frequency behavior of engine rotor systems. Therefore, it is necessary to predict their critical frequencies and dynamic behavior carefully. The simplified approach of the one-dimensional and two-dimensional elements can be used to predict critical frequencies and critical mode shapes in many cases, but the use of three-dimensional elements is the best method to achieve the goals of a modal analysis. This research explores the effect of a bird strike on the critical frequencies of an engine rotor. The changes in critical mode shapes and critical frequencies as a result of a bird strike on an engine blade are studied in this research. Commercially available analysis software ANSYS version 18.2 is used in this study. In order to account for the material nonlinearities, a Johnson Cook material model is used for the fan blades and an isotropic&ndash;elastic&ndash;plastic&ndash;hydrodynamic material model is used for modeling the bird. The bird strike event is analyzed using Eularian and smoothed particle hydrodynamics (SPH) techniques. A difference of 0.1% is noted in the results of both techniques. In the modal analysis simulation of the engine rotor before and after the bird strike event, the critical failure modes remain same. However, a change in the critical frequencies of the modes is observed. An increase in the critical frequencies and excitation RPMs (revolution per minute) of each mode are observed. As the mode order is increased, the higher the rise in critical frequency and excitation RPMs. Also, a change in the whirl direction of the different modes is noted