The Elements of Magnetics

2013 ◽  
Vol 1492 ◽  
pp. 35-46 ◽  
Author(s):  
Steve Constantinides

ABSTRACTThe 20th century saw rapid and dramatic improvements in permanent magnet materials. It has been 31 years since the discovery of neodymium-iron-boron and numerous companies and laboratories are seeking to produce a new and superior material. Topics discussed herein are material options, economics of selected materials and market drivers in material selection. Market issues include manufacturability by shape, size, and material yield; raw material supply including cost and dependability of the supply chain; raw material and magnet product price stability; development of applications based on commercial needs, government legislation and consumer demand. “Need is the mother of invention” and no discussion would be complete without covering why a new material would be beneficial from an applications point of view especially in energy production and consumption. Therefore, an introduction will be provided for select, major applications using permanent magnets and the growth forecasts for these.

Author(s):  
Anders Melin ◽  
David Kronlid

Energy production and consumption give rise to issues of justice for future humans. By analysing a specific case – Swedish energy politics – this article contributes to the discussion of how consideration for future humans should affect energy policy making. It outlines three different energy scenarios for the period 2035-2065 – the nuclear-renewables, the renewables-low and the renewables-high scenarios – and assesses them from the point of view of justice for future individuals by using the capabilities approach as a normative framework. We cannot make a definitive assessment of the different scenarios due to the great uncertainties involved in determining the impacts on individuals living between 2035 and 2065 and individuals born thereafter, but we still conclude that we have certain reasons to prefer the renewables-low scenario since it avoids certain risks connected with the other scenarios. The economic growth in this scenario is lower than in the others, but we question whether this is a disadvantage from the point of view of the capabilities approach. Keywords: energy scenarios, justice, future generations, capabilities approach


2011 ◽  
Vol 1 (6) ◽  
pp. 17 ◽  
Author(s):  
J. W. Hoyle ◽  
G. T. King

One should not lose sight of the fact that the origin of beaches goes back into antiquity. The story "begins with the origin of matter and continues through the aeons with the evolution of the solar system and the appearance of the Earth as a fiery ball gyrating in space. As one's focus narrows there is to be seen the cooling of that ball, the formation of dense clouds of water vapour in the atmosphere, the torrential rains and the beginnings of the seas. Perhaps it is at this point that the introduction is completed and the real story of the beaches begins, for with the rains came erosion of the land masses, and the transportation of the eroded material by river and rivulet towards the sea. At the brink of the ocean a brief halt is called in its journey, for here a portion of this eroded material takes position as beaches around die coast, before ultimately joining the remainder in the depths of the sea. For many thousands of years the sediment so formed and transported collected on the sea bed, consolidated and hardened and was transformed into the sedimentary rocks which, by adjustments in the Earth's crust, were later lifted above the surface of the sea to form new islands and continents. Still the rains fall, although perhaps not so heavily as before; still the processes of erosion continue upon the land masses, old and new, still a part of the products of this erosion remain for a while at the coastal fringe before they pass on to the ocean depths - the raw material of what may be, by completion of the cycle, the continents of tomorrow. Such is the sequence of events over a period of millions of years and, as the process continues during the millions of years which the future holds, the existing land masses will no doubt be eroded away and the materials of which they are composed will finally rest again on the bed of the sea. For so long as the seas have washed the shores, and the rains have fallen and reduced the mountains and high places, there have been beaches. Those beaches, which are found today may have existed from time immemorial in some form or other, perhaps since before life appeared on the surface of the Earth. Due to their position in the pattern of Nature they will have changed as the coastline changed, and as the eroded ingredients of the land which formed them changed. They will have grown when the new material supply exceeded the wastage, and they will have diminished when the wastage was more rapid than the replenishment. The changes which are taking place today and which are engaging the attention of the Civil Engineer, form an infinitesimally small incident in the history of the beaches; and in the considerations of the Engineer they should be related to the whole, of which they form a part.


2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sara Cura ◽  
Stefano Grimaldi ◽  
Pedro Cura ◽  
Pierluigi Rosina

The lithic assemblage of Ribeira da Ponte da Pedra site (OIS8-9) was produced, almost exclusively, through the exploitation of good quality quartzite fluvial pebbles with a regular morphology. Quartzite fluvial pebbles are the most common raw material found in the Middle Pleistocene occupation sites in Portugal. Such feature results from the easy availability of these pebbles in the valleys where the great majority of the archaeological sites within this chronology are located, and also because of the quartzite’s physical properties and suitability for knapping. In a techno-typological point of view, its lithic assemblage is characterized by the application of two main reduction sequences that result in abundant worked pebbles, retouched pebbles, cortical and semi-cortical flakes, retouched flakes, a few cores and rare bifacial artefacts. Some artefacts present irregular and variable edge modifications described as ‘atypical’ edge modifications that could edge damage resultant from their utilization. From a strictly technical point of view the assemblage can be described as quite simple, however we can envisage an inherent complexity starting in an accurate selection and exploitation of the quartzite pebbles, whose regular morphology allows a ‘predetermined’ production of regular blanks through simple actions. In order to better understand patterns of raw material selection and technical schemes adopted in the exploitation of the quartzite pebbles we compared a sample of pebbles collected in the same deposits identified in the site (t4 fluvial terrace deposits) with worked pebbles that have 1 or 2 removals that had not altered significantly the original morpho-volumetry of the pebbles. The goal of this comparison was to verify if there was a selection of the fluvial pebbles based on texture and morpho-volumetry and if so, relate such selection with the technical schemes identified by technological study of the assemblage.


2015 ◽  
Vol 2 (1) ◽  
pp. 6-12
Author(s):  
Agus Sugiarta ◽  
Houtman P. Siregar ◽  
Dedy Loebis

Automation of process control in chemical plant is an inspiring application field of mechatronicengineering. In order to understand the complexity of the automation and its application requireknowledges of chemical engineering, mechatronic and other numerous interconnected studies.The background of this paper is an inherent problem of overheating due to lack of level controlsystem. The objective of this research is to control the dynamic process of desired level more tightlywhich is able to stabilize raw material supply into the chemical plant system.The chemical plant is operated within a wide range of feed compositions and flow rates whichmake the process control become difficult. This research uses modelling for efficiency reason andanalyzes the model by PID control algorithm along with its simulations by using Matlab.


2008 ◽  
Vol 59 (2) ◽  
pp. 129-134
Author(s):  
Ion Teoreanu ◽  
Roxana Lucia Dumitrache ◽  
Stefania Stoleriu

Any change of the raw material sources for glazes, economically, ecologically motivated, and also from the glaze quality point of view, is conditioned by the molecular formula rationalization and by the variation limits of the molecular formula, respectively. The proper glaze compositions are placed within their limit variation intervals with optimized processing and utilization properties. For this purpose, the rationalization criteria and procedures of molecular formulas are summarized in the present paper, as well as the results referring to their rationalization obtained in the authors� previous work. Thus, one starts from a base of raw materials that are selected, usable and also accessible for the design and producing of the glazes. On these bases the groundwork and the design equation for the glaze recipes are developed, exemplified for a single glaze. For an easy access to results, computer programs are used for an easy access to results.


Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 682
Author(s):  
Zita Szabó ◽  
Viola Prohászka ◽  
Ágnes Sallay

Nowadays, in the context of climate change, efficient energy management and increasing the share of renewable energy sources in the energy mix are helping to reduce greenhouse gases. In this research, we present the energy system and its management and the possibilities of its development through the example of an ecovillage. The basic goal of such a community is to be economically, socially, and ecologically sustainable, so the study of energy system of an ecovillage is especially justified. As the goal of this community is sustainability, potential technological and efficiency barriers to the use of renewable energy sources will also become visible. Our sample area is Visnyeszéplak ecovillage, where we examined the energy production and consumption habits and possibilities of the community with the help of interviews, literature, and map databases. By examining the spatial structure of the settlement, we examined the spatial structure of energy management. We formulated development proposals that can make the community’s energy management system more efficient.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.


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