Rheology of StelliteTM 21 Alloy in Semi-Solid State

The main objective of this study was to conduct an analysis of the rheological properties of StelliteTM 21 alloy in the semi-solid state, as the results could be used for identifying the appropriate temperature range for thixoforming of this alloy, and a secondary objective of the experimental work was the development of mathematical model of the alloy’s apparent viscosity. Such viscosity models are necessary for numerical simulations of the thixoforming processes. The StelliteTM 21 alloy exhibits high hardness and thus shaping in the semi-solid state is promising route of production of parts from this alloy. Within the confines of experimental work the measurement methods of the rheological properties at high temperatures was developed. They are based on the use of specially designed viscometer equipped with high temperature furnace. Keywords: thixoforming, rheological properties, viscosity, thixotropy, StelliteTM alloy

Book review: English-Medium Instruction from an English as a Lingua Franca Perspective: Exploring the Higher Education Context, by K. Murata (Ed). Oxford: Routledge (2019). 289 pp.

Kumiko Murata’s book provides a timely contribution to the rapidly expanding literature on English Medium Instruction (EMI) in higher education (HE). EMI is the use of English to teach and learn academic subjects in contexts where English is not the majority language of the population. In such contexts, English as a Lingua Franca (ELF) is used; that is, the use of English to communicate between speakers with different first languages. This is relevant to an EMI context where lecturers and students may not share the same first language, and therefore rely on English to communicate.This book is part of the Routledge Research in Language Education series which aims to provide a platform for scholars at any career stage to discuss key issues in Language Education. This series is recommended for a wide variety of stakeholders; students, teachers, teacher educators, teaching material designers, applied linguists, as well as policymakers

Heat transfer through a constant-property laminar boundary layer Part 1 - calculations based on Lighthill's method Part 2 - calculations based on Stratford's method

Part I. Two methods are derived for calculating the heat transfer through a constant-property laminar boundary layer, that depend respectively on approximations valid at low and high values of σ, the Prandtl number. The high σ approach is a development of an earlier method, due to Lighthill; an additional term is now retained in the assumed form of the velocity profile near the wall. The low σ approach is effectively an extension to Prandtl numbers of order unity of the limiting solution of Morgan et al, valid as σ -> 0. A certain amount of empirical fitting ensures good agreement with the 'similar' solutions When the methods are used to calculate heat transfer in flow past a circular cylinder, a comparison with experiment suggests that the high a approximation is at least as good as other methods of calculating heat transfer, and that the low σ approximation may be even better. Part II. The now well-known technique of Stratford is used to calculate heat-transfer rates through a constant-property laminar boundary layer with an arbitrary adverse pressure gradient. The velocity profiles are assumed to have been calculated by Stratford's method, linking solutions valid respectively in the inner and outer parts of the boundary layer, and a similar division is made in analysing the temperature profiles. A particularly simple formula is obtained for the heat-transfer rate at the wall. The accuracy of the method, estimated by comparison with such exact solutions as are available, is found to be reasonable

Properties of R-HPDC AI-Zn-Mg-Cu aluminium alloys

Five different Al-Zn-Mg-Cu alloys were produced by rheo-high pressure die casting (R-HPDC) of which the as-cast microstructures were characterised with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The primary aluminium grains and eutectic phases were observed with SEM backscattered electrons (BSE). The overall compositions of the eutectics were measured with EDX and were found to be relatively similar, regardless of the alloy composition. Two further Al-Zn-Mg-Cu alloys were produced with the same compositions as the eutectics in the R-HPDC alloys. These eutectic alloys were also characterised with SEM and EDX. One of the R-HPDC alloys was also cooled in vacuum and characterised with SEM and EDX. The as-cast alloys were characterised with differential scanning calorimetry (DSC) and X-ray diffraction (XRD). DSC results showed that all the as-cast alloys had different melting points depending on the phases present in the solidified alloy. XRD showed that the as-cast alloy eutectics had one of two crystal structures for the second component besides the (Al) phase, which were hexagonal or cubic, or a combination of both depending on the overall composition and cooling rate. Modelling of non-equilibrium alloy solidification was also done using Thermo-Calc with the most recent aluminium database. It was found that the calculated and measured results compared favourably. The remaining phases in all the alloys, after homogenisation and artificial ageing, were characterised with SEM and EDX to assess the influence of impurity elements. It was found that Fe and Mn react with Cu, and Si with Mg. Experiments were also conducted to assess the effect of composition on the hardness and yield strength of all the alloys after homogenisation and artificial ageing. A precipitate composition for the T6 condition, from literature, was used for the calculations. It was found that there were reasonable straight line relationships if the impurity elements were neglected. On the other hand, there were near perfect linear fits when the influence of impurity elements was taken into account. The optimum Al-Zn-Mg-Cu alloying ratio for a dilute aluminium alloy is the composition of the precipitate modelled. The ratios were Al7.4Zn45.4Mg38.6Cu8.6 for the T6 condition and Al15Zn39Mg33Cu13 for the T73 condition

An Economic Analysis of the Predator Problem in the Range-Sheep Industry in Utah

The economic effects, to the Utah range-sheep operation and to the economy of the state of Utah, of predation upon sheep were studied by use of a personal interview survey. This survey sampled 20 percent of the range-sheep operations in Utah. The sheep and lamb death loss from predation was found to be 61.0 sheep and lambs per 1,000 head of ewes in fiscal 1969. The survey. also showed that 71.36 percent of the losses were lambs and 28.64 percent were ewes. The total economic·lpss to Utah sheep ranchers was calculated to be 1,062,502 dollars as a result of predation, in fiscal year 1969. Using the Type II multiplier of 4.330 for the livestock industry, published by the University of Utah, the total economic loss, resulting from predation upon sheep and lambs, to all sectors of the economy of the state of Utah, was determined as 3,901,854 dollars The bounty system was found to be the least costly method of controlling predators, followed by private control methods. The Utah District, Division of Wildlife Services, had the highest control cost per predator, and this increased drastically when a change of name and changes in personnel and policies were instituted for this federal predator control agency

Success in English Medium Instruction in China: Significant Indicators and Implications

This article reports a mixed-methods study that investigates academic success in English Medium Instruction (EMI) at a Chinese state university. Questionnaire, exam score (n=100), and semi-structured interview data (n=29) was collected from second-year undergraduate students majoring in Business Management. Content-related language proficiency, perceived success, and motivation were explored as possible significant predictors of academic success in EMI. Business English proficiency was a statistically significant predictor, highlighting that students with a lower level of proficiency need supplementary linguistic support in order to fully succeed in their EMI studies. Language learning motivation did not predict academic success, echoing previous findings (Rose et el., 2019). Perceived success in EMI did predict actual success in EMI, highlighting the need to enhance students’ perceptions of their own ability to succeed in EMI. Qualitative data revealed that students’ perceptions of success in EMI centred around content knowledge acquisition, improved English proficiency, knowledge application and transformation, and forming new modes of thinking. Practical implications for pedagogy are discussed

“I just wanted to learn Japanese and visit Japan”: The incentives and attitudes of international students in English-Medium Instruction programmes in Japan.

With growth in English-Medium of Instruction (EMI) in higher education, there have been increasing calls for research on this expansion, particularly the challenges facing students. Despite the growth in international students and ambitious target recruitment numbers in places like Japan, much of the EMI research to date focuses on home students. This article reports on a study with international students enrolled on EMI programmes in six Japanese universities. Data was collected using open-ended questionnaires (n=102), interviews (n=10) at four of the six universities, and 3 focus groups (Japanese and international students) at three of the six universities. Results show that unlike home students, international student enrollment in EMI programmes is not linked to goals to improve English proficiency; many are simply interested in Japan or learning Japanese. While students recognized the benefits of EMI, they discussed numerous challenges, particularly language-related issues in classrooms where they study with students of varying levels of English proficiency. This study provides key insights into EMI policy implementation and the needs of an important group of stakeholders who have long been high on the government’s internationalization agenda in Japan