THE GRAIN COARSENING AND SUBSEQUENT TRANSFORMATION OF AUSTENITE IN THE HSLA STEEL DURING HIGH TEMPERATURE THERMOMECHANICAL PROCESSING

In heavy steel sections, fundamental properties such as strength and toughness are improved remarkably by refining and homogenizing the final ferrite microstructure. Conventionally, the microstructural refinement of the final ferrite depends mainly on the austenite grain size, morphology and composition prior to the phase transformation as well as the cooling rate during the transformation. The production of heavy sections by universal-type rolling mills takes place at elevated temperature (above 1200 ºC) followed by low cooling rates (<0.1 ºC/sec). These processing conditions produce coarse austenite grains and subsequently coarse ferrite grains in addition to other undesirable low temperature transformation products. In heavy steel sections, therefore, the refinement of the ferrite microstructure through modern TMP techniques is not feasible. The main objective of this study is to investigate the feasibility of refining the ferrite microstructure and eliminate the high-carbon low transformation products in heavy steel sections using the particle-stimulated nucleation, PSN, mechanism to enhance the nucleation of the intragranular ferrite, IGF.In this investigation, the MnS and Ti-oxide inclusions were used to promote the intragranular ferrite (IGF) nucleation mechanism in a typical ASTM A572 grade 50 Steel. This work included the study of the decomposition behavior of coarse grained austenite and nucleation of the IGF as a function of very slow cooling rate. In addition, the effects of the inclusions type, size and volume fraction on the kinetics (nucleation and growth) of IGF were investigated. The main findings of this research were that the refining of ferrite microstructure is achieved, successfully, through enhancing the IGF nucleation with implementing of the PSN mechanism. Additionally, the efficiency of the inclusion as an IGF nucleation site is mainly related to the inclusion size and type

Equivalences of comodule categories for coalgebras over rings

In this article we defined and studied quasi-finite comodules, the cohom functors for coalgebras over rings. linear functors between categories of comodules are also investigated and it is proved that good enough linear functors are nothing but a cotensor functor. Our main result of this work characterizes equivalences between comodule categories generalizing the Morita-Takeuchi theory to coalgebras over rings. Morita-Takeuchi contexts in our setting is defined and investigated, a correspondence between strict Morita-Takeuchi contexts and equivalences of comodule categories over the involved coalgebras is obtained. Finally we proved that for coalgebras over QF-rings Takeuchi's representation of the cohom-functor is also valid.Comment: 30 pages, xy-pic. To appear in Jornal of pure and applied algebr

Faster Motion on Cartesian Paths Exploiting Robot Redundancy at the Acceleration Level

The problem of minimizing the transfer time along a given Cartesian path for redundant robots can be approached in two steps, by separating the generation of a joint path associated to the Cartesian path from the exact minimization of motion time under kinematic/dynamic bounds along the obtained parameterized joint path. In this framework, multiple suboptimal solutions can be found, depending on how redundancy is locally resolved in the joint space within the first step. We propose a solution method that works at the acceleration level, by using weighted pseudoinversion, optimizing an inertia-related criterion, and including null-space damping. Several numerical results obtained on different robot systems demonstrate consistently good behaviors and definitely faster motion times in comparison with related methods proposed in the literature. The motion time obtained with our method is reasonably close to the global time-optimal solution along same Cartesian path. Experimental results on a KUKA LWR IV are also reported, showing the tracking control performance on the executed motions

ANN for Predicting Temperature and Humidity in the Surrounding Environment

Abstract: In this research, an Artificial Neural Network (ANN) model was developed and tested to predict temperature in the surrounding environment. A number of factors were identified that may affect temperature or humidity. Factors such as the nature of the surrounding place, proximity or distance from water surfaces, the influence of vegetation, and the level of rise or fall below sea level, among others, as input variables for the ANN model. A model based on multi-layer concept topology was developed and trained using data from several regions in the surrounding environment. The evaluation of testing the dataset shows that the ANN model is capable of correctly predicting the temperature with 100% accuracy

Egyptian Revolution of 2011 and the Power of Its Slogans: A Critical Discourse Analysis Study

Egypt, the most populated country in the Arab world, erupted in mass protests in January 2011 against the oppressive rule of President Hosni Mubarak. Protesters all over Egypt in general and in Tahrir Square in Cairo wanted Mubarak to leave. Protesters used different dialects, languages, and modes to get their message across. After 18 days of angry protests and after losing the support of the military and the US, Mubarak finally understood the message and resigned on Feb. 11, ending almost 30 years of dictatorial rule. This article builds on studies in Critical Discourse Analysis (CDA) and its implementation of interdisciplinarity to investigate the slogans―fixed expressions, usually chosen carefully by organizers and activists, which are often chanted by political groups and protestors at demonstrations that were used during the Egyptian revolution in late January and February 2011. Moreover, the article shows how CDA―through embracing text as a dialogue and site for interaction, social goods and social languages, interpersonal relations and discourse, multimodality, and intertextuality can help to produce theoretically sound interpretation that is appropriate for the analysis of how Egyptians used the power of language through these slogans to empower themselves, challenge their government, and overthrow the former president Hosni Mubarak

Evaluation of the pharmacist role in discharge from hospital

When patients are discharged from hospital it is vital that the information regarding their medication is provided to the General Practitioner (GP) as accurately and efficiently as possible. However errors frequently occur and the NHS is currently investigating how to improve discharge systems, one approach is to use pharmacists to write discharge prescriptions or To Take Out (TTOs). The aim of the audit was to compare discrepancies on TTOs (To take out) between different transcribers: doctors, pharmacists and nurses and identify factors which are predictors of discharge discrepancies. Discharge summaries written by different transcriber groups from three study wards at one hospital were selected. Discrepancies were identified by comparing the unauthorised TTO (TTO prior to final pharmacy check) to authorised TTOs, medical notes and prescription chart. Discrepancies were classified according to the CHUMS classification procedure. Logistic regression was used to identify predictors of discrepancies. Two hundred and fifteen TTOs were included in the audit written by pharmacists, doctors and nurses (n= 85, 81 and 49, respectively). Nearly 50% of TTOs contained at least one discrepancy, the most common of which was omission of a medicine. The significant predictors of discrepancies were if a TTO was written by a nurse or a doctor or if there was more than three hours between an unauthorised TTO being authorised (Odds ratios were 3.45, 2.26 and 3.88, respectively). Overall this study demonstrates the using pharmacist transcribers is at least as safe as previous systems and is unlikely to introduce additional discrepancies. Alternative approaches which support the healthcare team to work closer together at the time of discharge should reduce delays authorising the TTO and reduce discrepancies

Empirical investigation of water pollution control through use of Phragmites australis

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research study addresses a problem of water pollution caused by heavy and toxic metals Cd, Cr, Cu and Pb. The thesis proposes the use of the technique of phytoremediation using Phragmites australis (PA) plants that have the capacity to absorb and to accumulate such metals in their roots and leaves. The metal uptake and their location of accumulation in the PA plants were determined using flame atomic absorption spectroscopy (FAAS) and transmission electron microscopy (TEM) respectively. Leachates from contaminated plant biomass were mixed with silver nitrate to assess the manufacture of metal nanoparticles as an added value step in the process from remediation to biomass disposal. Silver nanoparticles were readily manufactured by the leachates without, with the exception of copper, any incorporation of the pollutant metal. The presence of copper in the manufactured silver nanoparticles may be of some commercial use. The results obtained show that PA plants will accumulate toxic metals when in hydroponic culture and that the majority of the accumulated metals are sequestered in the roots and do not enter the aerial parts of the plants in significant amounts. Silver nanoparticles were manufactured from the biomass using a low energy route with no additional chemicals, apart from silver nitrate thus reducing the environmental load that would otherwise be present if a chemical means of nanoparticle production was used

The Pollution of Water by Trace Elements Research Trends

Water pollution has been a growing issue for the last decades. This is mainly because of the boost in human population, and the motivations that lead to technological advances for the welfare of the society. Water pollution originates from different sources such as agricultural, municipal, industrial, and landfills drainage waters. These pollutants, which are either organic, nutrient, or heavy metals pollutants, are very deleterious to the natural ecosystems and eventually harmful to humans. Different procedures have been proposed for handling heavy metals water pollution, which encompass electro-osmosis, ion exchange, electro-kinetic, sludge activation, as well as phytoextraction. Water contaminants are also removed using flotation, membrane filtration, aeration, precipitation, coagulation—flocculation, ion exchange, and electrochemical treatment. These procedures are costly and have prompted the use of other techniques, such as phytoremediation. Phytoremediation involves the utilization of plant species to alleviate the impacts of environmental pollution. It could be implemented to eliminate pollutants from various natural ecosystems including water, soil, and air or to develop new vegetation growth on disturbed or barren ground. Different plant species have been used for phytoremediation. This chapter addresses trace elements pollution of natural water resources in details and the abilities of Aquatic plant communities such as Reed plants (Phragmites australis) to absorb soluble trace elements from water