Latent disciplinal clashes concerning the batch dissolution of minerals, and their wider implications

2018 ◽  
Vol 15 (2) ◽  
pp. 113 ◽  
Author(s):  
Victor W. Truesdale ◽  
Jim Greenwood
Keyword(s):  
Large Scale ◽  
Dissolution Kinetics ◽  
Mineral Dissolution ◽  
Atomic Scale ◽  
Rate Equations ◽  
Silicate Mineral ◽  
Waste Products ◽  
Calcite Dissolution ◽  
Macro Scale ◽  
Made In

Environmental contextMineral dissolution kinetics are important to understand natural processes including those increasingly used to store waste carbon dioxide and highly radio-active nuclides, and those involved in the amelioration of climate change and sea-level rise. We highlight a mistake made in the fundamental science that has retarded progress in the field for over 40 years. Its removal suggests improved ways to approach dissolution studies. AbstractMineral dissolution kinetics are fundamental to biogeochemistry, and to the application of science to reduce the deleterious effects of humanity’s waste products, e.g. CO2 and radio-nuclides. However, a mistake made in the selection of the rate equation appropriate for use at the macro-scale of the aquatic environment has stymied growth in major aspects of the subject for some 40 years. This paper identifies the mistake, shows how it represents a latent disciplinal clash between two rate equations, and explores the misunderstandings that resulted from it. The paper also briefly explores other disciplinal clashes. Using the example of calcite dissolution, the paper also shows how the phenomenon of ‘non-ideal’ dissolution, which is prevalent in alumino-silicate mineral dissolution, as well as with calcite, has obscured the clash. The paper provides new information on plausible mechanisms, the absence of which has contributed to the problem. Finally, it argues that disciplinal clashes need to be minimised so that a rigorous description of dissolution at the large scale can be matched to findings at the atomic, or near-atomic, scale.

Preliminary studies on the batch-dissolution kinetics of calcite with reactors open and closed to CO2

2019 ◽  
Vol 16 (2) ◽  
pp. 101
Author(s):  
Victor W. Truesdale ◽  
Jim Greenwood
Keyword(s):  
Climate Change ◽  
Rate Equation ◽  
Dissolved Inorganic Carbon ◽  
Preliminary Investigation ◽  
Dissolution Kinetics ◽  
Mineral Dissolution ◽  
Calcite Dissolution ◽  
Global Issues ◽  
Environmental Consequences ◽  
Reliable Solution

Environmental contextThe dissolution of minerals in fresh or sea-waters is a critical environmental process. The rate at which substances dissolve, from the dissolution of calcite crystals to the weathering of mountains, can influence major global issues such as climate change and sea-level rise. This paper explores a new solution-based rate equation for mineral dissolution that has profound environmental consequences. AbstractThis paper continues the search for a reliable, solution-based, rate equation for mineral dissolution, as the one dominant for over 40 years has recently been challenged by the Shrinking Object (SO) model. This study is needed to remedy several major environmental problems of immense social and economic importance including climate change, ocean acidification and industrial waste disposal. This paper describes the preliminary investigation of how reactors open and closed to CO2, which are used to study calcite dissolution, ought to be used with the SO model to gain maximum advantage. The open reactor is re-conceptualised as a constant head device for dissolved inorganic carbon, to give the kineticist a mechanistic description of it, to flesh out the thermodynamic categorisation. Application of this reveals that the recent experiments conducted in a reactor blown with CO2-free N2, which were central to the establishment of the concept of non-ideal dissolution of calcite, would have exaggerated the effect. Although this current study was still unable to determine conditions where the effect was absent, it does seem that it will be possible to skirt around this in the future, by approximating the classic works on the variation with pH of the initial rate of dissolution to full reaction curves from the SO model, which are exponential. To guide workers towards a further round of laboratory investigation on this, practical work on the dissolution of calcite crystallites in 0.311M Tris buffer at pH 8 or 9, under various partial pressures of CO2, in different reactors, and under various stirring and filtration strategies, is presented. Improved data runs, with unparalleled, strategically-spaced samplings, which show up the finer details of dissolution, can now be anticipated.

scholarly journals Synthesis of Metal Organic Frameworks by Ball-Milling

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Cheng-An Tao ◽  
Jian-Fang Wang
Keyword(s):  
Ball Milling ◽  
Large Scale ◽  
Raw Materials ◽  
Metal Organic Frameworks ◽  
Research Topic ◽  
Mass Ratio ◽  
Time Consumption ◽  
Metal Organic ◽  
Short Time ◽  
Made In

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.

scholarly journals Land Use Transition and Driving Forces in Chinese Loess Plateau: A Case Study from Pu County, Shanxi Province

Land ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 67
Author(s):  
Han Huang ◽  
Yang Zhou ◽  
Mingjie Qian ◽  
Zhaoqi Zeng
Keyword(s):  
Land Use ◽  
Food Security ◽  
Loess Plateau ◽  
Large Scale ◽  
Driving Forces ◽  
Chinese Loess Plateau ◽  
Shanxi Province ◽  
Forest Land ◽  
Land Use Transition ◽  
Macro Scale

Land use transition is essentially one of the manifestations of land use/cover change (LUCC). Although a large number of studies have focused on land use transitions on the macro scale, there are few studies on the micro scale. Based on the data of two high-resolution land use surveys, this study used a land use transfer matrix and GeoDetector model to explore the spatial-temporal patterns and driving forces of land use transitions at the village level in Pu County over a ten-year period. Results show that Pu County has experienced a drastic process of land use transition. More than 80% of cropland and grassland have been converted to forest land, and over 90% of the expansion of built-up land came from the occupation of forest land, cropland, and grassland. The driving forces of land use transition and its magnitude depended on the type of land use. The implementation of the policy of returning farmland to forest, or grain-for-green (GFG) was the main driving force for the large-scale conversion of cultivated land to forest land in Pu County. In the context of policy of returning farmland to forests, the hilly and gully regions of China’s Loess Plateau must balance between protecting the ecology and ensuring food security. Promoting the comprehensive consolidation of gully land and developing modern agriculture may be an important way to achieve a win-win goal of ecological protection and food security.

scholarly journals Learning As It Happens: A Decade of Analyzing and Shaping a Large-Scale Online Learning System

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Matthieu J. S. Brinkhuis ◽  
Alexander O. Savi ◽  
Abe D. Hofman ◽  
Frederik Coomans ◽  
Han L. J. Van der Maas ◽  
...  
Keyword(s):  
Online Learning ◽  
Large Scale ◽  
Response Times ◽  
Learning System ◽  
Learning Gains ◽  
Online Experimentation ◽  
Quality Of Fit ◽  
Item Reliability ◽  
Made In

With the advent of computers in education, and the ample availability of online learning and practice environments, enormous amounts of data on learning become available. The purpose of this paper is to present a decade of experience with analyzing and improving an online practice environment for math, which has thus far recorded over a billion responses. We present the methods we use to both steer and analyze this system in real-time, using scoring rules on accuracy and response times, a tailored rating system to provide both learners and items with current ability and difficulty ratings, and an adaptive engine that matches learners to items. Moreover, we explore the quality of fit by means of prediction accuracy and parallel item reliability. Limitations and pitfalls are discussed by diagnosing sources of misfit, like violations of unidimensionality and unforeseen dynamics. Finally, directions for development are discussed, including embedded learning analytics and a focus on online experimentation to evaluate both the system itself and the users’ learning gains. Though many challenges remain open, we believe that large steps have been made in providing methods to efficiently manage and research educational big data from a massive online learning system.

The Big Push Déjà Vu: A Review of Jeffrey Sachs's The End of Poverty: Economic Possibilities for Our Time

2006 ◽  
Vol 44 (1) ◽  
pp. 96-105 ◽  
Author(s):  
William Easterly
Keyword(s):  
New York ◽  
Development Economics ◽  
Large Scale ◽  
The Poor ◽  
World Poverty ◽  
Incentive Problems ◽  
The 1950S ◽  
Déjà Vu ◽  
Big Push ◽  
Made In

Jeffrey Sachs's new book (The End of Poverty: Economic Possibilities for Our Time, Penguin Press: New York, 2005) advocates a “Big Push” featuring large increases in aid to finance a package of complementary investments in order to end world poverty. These recommendations are remarkably similar to those first made in the 1950s and 1960s in development economics. Today, as then, the Big Push recommendation overlooks the unsolvable information and incentive problems facing any large-scale planning exercise. A more promising approach would be to design incentives for aid agents to implement interventions piecemeal whenever they deliver large benefits for the poor relative to costs.

scholarly journals Calcite dissolution kinetics at the sediment-water interface in natural seawater

2017 ◽  
Vol 195 ◽  
pp. 70-83 ◽  
Author(s):  
Olivier Sulpis ◽  
Claire Lix ◽  
Alfonso Mucci ◽  
Bernard P. Boudreau
Keyword(s):  
Dissolution Kinetics ◽  
Natural Seawater ◽  
Water Interface ◽  
Calcite Dissolution

Oosterweel – from an underground and even underwater road infrastructure plan to an urban transformation project

2021 ◽  
Author(s):  
Luc Hellemans
Keyword(s):  
Traffic Flow ◽  
Large Scale ◽  
Good Reason ◽  
Urban Transformation ◽  
Construction Site ◽  
Successful Completion ◽  
Road Infrastructure ◽  
Living Space ◽  
The City ◽  
Made In

<p>For the coming ten years, the heart of Europe will turn into a gigantic construction site for works on one of the largest hubs of the continent: Antwerp. The Oosterweel Link is the project whereby the motorway ring around Antwerp is undergoing a metamorphosis to reinvigorate traffic flow and add living space to the City. The project had come to a standstill for several years as a result of protests by assertive citizens, but was given a second lease of life following a large-scale participation project.</p><p>To ensure its successful completion, unparalleled efforts are being made in the field and in the area of digitization. It is therefore with good reason that in Belgium the project is referred to as “the construction site of the century”.</p>

On the Early Cambrian age of two late orogenic granites from. west-central Ahaggar (Algerian Sahara)

1969 ◽  
Vol 6 (1) ◽  
pp. 25-37 ◽  
Author(s):  
J. Boissonnas ◽  
S. Borsi ◽  
G. Ferrara ◽  
J. Fabre ◽  
J. Fabries ◽  
...  
Keyword(s):  
Random Sampling ◽  
Field Data ◽  
Large Scale ◽  
Early Cambrian ◽  
Basement Complex ◽  
West Central ◽  
Algerian Sahara ◽  
Igneous Activity ◽  
Made In

The Pharusian belt of west-central Ahaggar belongs to the 'basement complex' underlying the Paleozoic and later sediments of the Sahara. This paper reports and discusses the Rb–Sr ages obtained on total rocks and minerals from two granitic stocks of the belt: the Tioueiine and Iskel intrusions.Both plutons gave good whole-rock isochrons, which show that the systems were closed 560 ± 40 m.y. ago with respect to Rb and Sr. This is, most probably, the age of crystallization. Three of the four values obtained on biotites are somewhat lower and scattered in the range 502–526 m.y. The discrepancies are probably due to deuteric reactions or incipient weathering. They can be ascribed neither to the loss of 87Sr during the cooling down of the granites, nor to rejuvenation by some later thermal or tectonic event.These studies confirm previous results of random sampling in Ahaggar and prove that large-scale igneous activity took place during the Early Cambrian Epoch. Knowing from field data that the Tioueiine and Iskel are late orogenic granites, it must be concluded that the Pharusian orogeny came to an end at that time.Such a result contradicts early assumptions, made in the field, of a middle Precambrian age for the Pharusian orogeny. It gives further weight to modern ideas concerning the 700–500 m.y. events in Africa, and it leaves time for erosion to create the Saharian platform before the deposition of the first Paleozoic sandstones.

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