Worked example for chemical dosing estimation

Keyword(s):  
2009 ◽  
Vol 23 (2) ◽  
pp. 129-138 ◽  
Author(s):  
Florian Schmidt-Weigand ◽  
Martin Hänze ◽  
Rita Wodzinski

How can worked examples be enhanced to promote complex problem solving? N = 92 students of the 8th grade attended in pairs to a physics problem. Problem solving was supported by (a) a worked example given as a whole, (b) a worked example presented incrementally (i.e. only one solution step at a time), or (c) a worked example presented incrementally and accompanied by strategic prompts. In groups (b) and (c) students self-regulated when to attend to the next solution step. In group (c) each solution step was preceded by a prompt that suggested strategic learning behavior (e.g. note taking, sketching, communicating with the learning partner, etc.). Prompts and solution steps were given on separate sheets. The study revealed that incremental presentation lead to a better learning experience (higher feeling of competence, lower cognitive load) compared to a conventional presentation of the worked example. However, only if additional strategic learning behavior was prompted, students remembered the solution more correctly and reproduced more solution steps.


2014 ◽  
Author(s):  
Charlyn W. Shaw ◽  
Rayne A. Sperling ◽  
David C. Falvo ◽  
Peter T. Olszewski

Author(s):  
Breen Creighton ◽  
Catrina Denvir ◽  
Richard Johnstone ◽  
Shae McCrystal ◽  
Alice Orchiston

The purpose of the research upon which this book is based was empirically to investigate whether the ballot requirements in the Fair Work Act do indeed impose a significant obstacle to the taking of industrial action, and whether those provisions are indeed impelled by a legitimate ‘democratic imperative’. The book starts from the proposition that virtually all national legal systems, and international law, recognise the right to strike as a fundamental human right. It acknowledges, however, that in no case is this recognition without qualification. Amongst the most common qualifications is a requirement that to be lawful strike action must first be approved by a ballot of workers concerned. Often, these requirements are said to be necessary to protect the democratic rights of the workers concerned: this is the so-called ‘democratic imperative’. In order to evaluate the true purpose and effect of ballot requirements the book draws upon the detailed empirical study of the operation of the Australian legislative provisions noted above; a comparative analysis of law and practice in a broad range of countries, with special reference to Canada, South Africa, the United Kingdom and the United States; and the jurisprudence of the supervisory bodies of the International Labour Organisation. It finds that in many instances ballot requirements – especially those relating to quorum – are more concerned with curtailing strike activity than with constructively responding to the democratic imperative. Frequently, they also proceed from a distorted perception of what ‘democracy’ could and should entail in an industrial context. Paradoxically, the study also finds that in some contexts ballot requirements can provide additional bargaining leverage for unions. Overall, however, the study confirms our hypothesis that the principal purpose of ballot requirements – especially in Australia and the United Kingdom – is to curtail strike activity rather than to vindicate the democratic imperative, other than on the basis of a highly attenuated reading of that term. We believe that the end-result constitutes an important study of the practical operation of a complex set of legal rules, and one which exposes the dichotomy between the ostensible and real objectives underpinning the adoption of those rules. It also furnishes a worked example of multi-methods empirical, comparative and doctrinal legal research in law, which we hope will inspire similar approaches to other areas of labour law.


2015 ◽  
Vol 9 (12) ◽  
pp. e0004211 ◽  
Author(s):  
Magali Teurlai ◽  
Christophe Eugène Menkès ◽  
Virgil Cavarero ◽  
Nicolas Degallier ◽  
Elodie Descloux ◽  
...  

Author(s):  
W. F. Carey ◽  
G. J. Williamson

On plants in which gases are processed, the gases are often brought into direct contact with water—usually in packed towers. The purpose may be to cool a hot gas, to increase the humidity of a gas, or, in the well-known special case of water-cooling towers, to cool water by contact with atmospheric air. These processes involve simultaneous transfers of sensible heat and water vapour, and existing methods of analysis are complex and laborious, except for the cooling of water, for which Merkel's total-heat method has long been available. Merkel's approximate solution offers the engineer a simple method of working out, for any operating conditions, the amount of heat transferred and the “driving force” available for transferring it. The present paper generalizes the total-heat method and, with a permissible sacrifice in accuracy, preserves the essential simplicity of the water-cooling treatment for gas-cooling and humidification processes. To complete the design of a packed tower, a knowledge is required of the characteristics of the packing. Information obtained in small towers is given for a number of packings, and a worked example shows how to apply the method of treatment, and the packing data presented, to the design of a large plant tower.


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