Small Hematite Nanoparticles from the Kiruna-Type Ore; Evaluation of Declined Balance Limit of the Attrition Process and Their Catalytic Properties

2021 ◽  
Vol 21 (12) ◽  
pp. 6000-6006
Author(s):  
Majid Mostaghelchi ◽  
Mohammad Zendehbad ◽  
Christian L. Lengauer

Hematite nanoparticles possess unique properties which have motivated substantial attention for numerous applications, including environmental remediation and wastewater treatment as a promising novel technology. The magnetite-silicate raw material of Kiruna-type ore has been introduced as an innovative precursor, decreasing the attrition balance limit for large-scale production of the ball-mill-derived hematite nanoparticles below the critical size. In this study, the hypothesis and the postulated role of quartz in the effective size reduction process were further investigated. The prepared samples were characterized in detail via X-ray fluorescence (XRF) and powder X-ray diffractometry (pXRD) to be compared with the previous results. Furthermore, the catalytic and photocatalytic activities of the obtained nanoparticles were evaluated in the oxidation reaction of a common persistent sulfo-organic contaminant. The results exposed outstanding reactivity, particularly in their photocatalytic performance, suggesting them as a strong oxidizing agent and active photocatalyst, which greatly promises many possible applications including water and environmental remediation.

Author(s):  
Samira Nuhanovic-Ribic ◽  
Ermanno C. Tortia ◽  
Vladislav Valentinov

Over the last decades, agricultural co-operatives grew substantially in most developed and developing countries, often reaching dominant market positions. We inquire into the economic mechanism behind this growth, by elaborating on the relation between co-operative identity and co-operative benefits. We highlight the ability of agricultural co-operatives to co-ordinate large-scale production, to monitor work contributions and product quality, and to ensure economic independence of farmer members. Following the two principal streams in the economic literature, we distinguish between the conceptions of agricultural co-operatives as units of vertical integration and as firms characterized by common governance of collective entrepreneurial action and ability to reduce transaction costs and economic risk. We describe the financial and governance limitations of agricultural co-operatives while taking account of new co-operative models presenting institutional tools introduced to overcome these limitations. We conclude by suggesting directions for enhancing the role of co-operatives in agricultural and rural development.


2012 ◽  
Vol 517 ◽  
pp. 430-436
Author(s):  
J.L. Akasaki ◽  
E.J. Silva ◽  
L.C. Sousa ◽  
J.L.P. Melges ◽  
M.M. Tashima ◽  
...  

Rice production in Brazil in 2010 was approximately 12,2 million tons, and to reach that amount several planting techniques were used with different strains of rice in different rice-growing areas. Since Rice Husk Ash (RHA) is the pozzolan of vegetable origin most studied by researchers working in the area of pozzolanic materials, the present paper evaluates the influence that the form of planting, the climate, the soil, the strain of rice and the origin/amount of nitrogen-based fertilizers used in rice cultivation has on the chemical composition and crystallographic properties of RHA. The results obtained in this paper, confirm the importance of carrying out routine chemical analysis and X-Ray diffraction to maintain the quality control of the CCAs produced, because in situations of large-scale production, husks of different origins may be used.


Author(s):  
Filippo Romoli ◽  
Estelle Mossou ◽  
Maxime Cuypers ◽  
Peter van der Linden ◽  
Philippe Carpentier ◽  
...  

A novel vitreous carbon mount for macromolecular crystallography, suitable for neutron and X-ray crystallographic studies, has been developed. The technology described here is compatible both with X-ray and neutron cryo-crystallography. The mounts have low density and low background scattering for both neutrons and X-rays. They are prepared by laser cutting, allowing high standards of production quality, the ability to custom-design the mount to specific crystal sizes and large-scale production.


2006 ◽  
Author(s):  
S. Kraft ◽  
M. Collon ◽  
M. W. Beijersbergen ◽  
M. Bavdaz ◽  
D. H. Lumb ◽  
...  

1969 ◽  
Vol 70 (4) ◽  
pp. 346-354
Author(s):  
D. A. Long ◽  
D. C. Edwards ◽  
A. W. Phillips ◽  
A. J. Woiwod

The Wellcome Foundation is part of the M.R.C. Working Party on A.L.S. and the main role of the Foundation, as agreed with the Working Party as a whole, is to produce A.L.S. on a large scale for use in man.In Great Britain, the use of any new therapeutic agent is controlled by authority, in this case the Dunlop Committee. Before this committee could be approached for a licence to market such a product, it would be necessary for the pharmaceutical company concerned to have established conditions for large-scale production.


Revista CERES ◽  
2014 ◽  
Vol 61 (6) ◽  
pp. 983-988 ◽  
Author(s):  
Vivian Pupo de Oliveira Machado ◽  
Ana Claudia Pacheco ◽  
Marcia Eugenia Amaral Carvalho

The production of medicinal plants as raw material for industry must associate quality with biomass formation and, with this purpose, the application of plant growth regulators has been studied in these crops. The objective of this study was to evaluate the effect of a biostimulant on growth, inflorescence production and flavonoid content in marigold. The experiment was conducted in a greenhouse and the treatments consisted of increasing doses of the biostimulant (0, 3, 6, 9, 12 and 15 mL L-1) applied by foliar spraying in ten consecutive applications. The experiment was arranged in a completely randomized design, with six treatments and ten repetitions. The number of leaves and flowerheads and dry matter of roots increased linearly with increasing doses of the growth promoter, with 20%, 36.97% and 97.28% increases, respectively, compared with the control. The total dry mass and shoot dry mass showed maximum values at the highest dose tested of 15 mL L-1 (with increases of 40.09% and 46.30%, respectively). Plant height and flavonoid content reached the highest values at a dose of 6 mL L-1. The biostimulant promoted the development of marigold and positively influenced the synthesis of the secondary compound of medicinal interest. Among the tested doses, the application of rates between 6 and 9 mL L-1 of the biostimulant is recommended for more efficient large-scale production of marigold.


2021 ◽  
Vol 75 (9) ◽  
pp. 752-756
Author(s):  
Jakob J. Mueller ◽  
Hans H. Wenk

Biosurfactants are surface-active molecules, developed by nature through evolution and naturally produced by different microorganisms. The most prominent examples are rhamnolipids and sophorolipids, molecules which contain hydrophilic sugar head groups and hydrophobic alkyl residues leading to an amphiphilic behavior with unique properties. Recent developments in the field of biotechnology enable the large-scale production of these biological molecules. The raw material basis is 100% renewable since sugars and oils are used as major raw materials. Additionally, biosurfactants are fully biodegradable, which allows the path back into the natural cycles. In comparison to established standard surfactants like SLES/SLS (sodium laureth (ether) sulfates) or betaines, rhamnolipids are much milder and, at the same time, show similar or even better performance in household or personal care applications. Foam behavior, solubilization and cleaning effectiveness are examples where these natural substances give excellent results compared to the synthetic benchmarks. The commercialization of biosurfactants at industrial scale now offers alternatives to consumers seeking sustainable solutions, without compromising performance. Biosurfactants combine both and set a new standard for surfactant applications.


2020 ◽  
Vol 20 (10) ◽  
pp. 6525-6531
Author(s):  
Majid Mostaghelchi ◽  
Jani Kotakoski ◽  
Christian Rentenberger ◽  
Christian L. Lengauer

The wide range of actual and potential applications of nanoparticles, highlight the necessity of a reliable production method for both quality and quantity of the products. Mechanical attrition is one of the first well-known techniques used to produce nanoparticles. However, these approaches have been restricted to produce uniform particles below the critical size of 15 nm because of the attrition balance limit. This paper introduces the magnetite–silicate raw material of a Kiruna-type ore deposit as a novel precursor, which enables the production of small iron oxide nanoparticles below the critical size by mechanical attrition. X-ray fluorescence (XRF), powder X-ray diffractometry (pXRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used for characterization of the precursor and obtained nanoparticles. The results indicate that the particles with a mean diameter of 10.7(2.7) nm consist of mainly less than one crystallite. The significant size reduction below the attrition balance limit can be attributed to the quartz content of the raw material, which operated as supporting micro-balls for transferring the energy during the milling process.


2011 ◽  
Vol 675-677 ◽  
pp. 223-226
Author(s):  
Hong Zhao ◽  
Jin Hua Yao ◽  
Shu Bao Jin ◽  
Li Jun Liang

Strong alkali anion exchange resin was employed as a hydroxyl source in the synthesis. OH- releasing rates were easily controlled by varying precursor salts, salt concentrations and temperatures, etc. The ratio between the nucleation speed and the speed of oxide crystallite growth was adjusted to favor the anisotropic growth of the crystal. Zinc and aluminum nano-sized oxide were obtained in various morphologies. X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersion Spectroscopy (EDS) were employed to characterize the products. It is ascertained that the surface reaction on the resin and the mechanical grinding are the key steps in controlling the product morphology. The results show the flexibility and possibility of large scale production of various nano metal oxides and as well as mixed oxides.


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