Modification of structure and conductivity of nanohorns by toluene addition in carbon arc

Abstract

In the present work, we compare the structure and transport properties of carbon nanohorns (CNHs) synthesized by arc evaporation of graphite alone and with the addition of some portion of toluene. The materials have been investigated using transmission electron microscopy, Raman and infrared spectroscopies, thermogravimetric and BET analyses. The addition of a small amount of toluene during the evaporation of graphitic rod increases the length of CNHs, affects their hierarchical arrangement in aggregates and results in surface functionalization. All these features significantly enhance the conductivity of CNHs obtained with toluene additive in comparison with the pristine CNHs.     

An evaluation of Acacia mearnsii tannin as an aluminum corrosion inhibitor in acid,alkaline, and neutral media

The electrochemical behavior of aluminum in tannin from Acacia mearnsii bark was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in media under three different pH conditions: acid, alkaline, and neutral. A relationship among pH, polymerization grade (PG), zeta potential, surface, and electrochemical properties was observed in the inhibition performance of the tannin. At high pH, the oligomer structure of the tannin was affected, resulting in a low PG (4) and high zeta potential (−75 mV), and consequently, the inhibition efficiency decreased (68%) in comparison with that in acid (99%) and neutral media (96%). The values obtained indicate a physisorption mechanism for the aluminum corrosion inhibition in the studied conditions.     

Mine inonoations

The paper describes the types of inundations affecting underground mining operations together with their safety, operational, and stability implications. A critical analysis has highlighted three major causes of inundations. These have been classified as event controlled, accidental or spontaneous. The event controlled inundations are associated with the development of fracture zones around a longwall working and followed by main and periodic roof falls in caved mine workings, particularly in coal mines. An approximate theory to predict the event of main and periodic roof falls in the goaf behind the long wall face is given. These types of inundations have been illustrated with several case histories.     

Formation of new functional materials and device heterostructures on the basis of nanosystems of superionic conductors

Search for conditions of conservation of fast ionic transport (FIT) in nanosystems of advanced superionic conductors (ASIC)[1-4] and synthesis of new types of device thin-film heterostructures on this basis is a fundamental scientific problem. ASICs (α-AgI, solid electrolytes of the family RbAg4I5, etc. ) are crystals with a record high level of ionic conductivity and a low value of activation energy E～0. 1 eV.     

应用泡沫浮选萃取法从排放水中回收钼

根据实验室的试验结果，推荐应用浮选萃取联合工艺从水溶液中回收Mo(Ⅵ）。这一工艺包括制取以钼酸铵形式的商品，和对所有的有机试剂作再生处理。萃取Mo(Ⅵ）的准备系统，应包括在反萃取胺和用NaOH使水溶液碱化到pH=12以后，通过添加水溶液以使煤油、壬醇和AHII捕收剂按规定的比例进行混合等作业。对在萃取器中获得的混合液进行相分离后，有机溶液可用作泡沫浮选萃取Mo(Ⅵ）的萃取剂，而水溶液则加入到原始溶液中。     

Zu Fragen der Ausbildung und Weiterbildung im österreichischen Bergbau

Training and continuous education is today for the management of a mineral producing operation more important than ever before. The focus of education today in the field of mineral producing industry has not only to be dedicated versus the needs of the industry but also versus the importance of the ever increasing need of societal acceptance of industrial operations. Therefore it is expected that graduates from mining schools not only have a good knowledge of technical and economical subjects but also a good background for the realisation of environmental and safety targets for the people at work and in the neighbourhood of an operation. A strong request to the education and training at university level is therefore not only to deliver a broad knowledge but also the formation of a basis which allows to obtain authority for functions as “safety expert”, “Mine rescuer”, “waste disposal expert” and others. In the text the contents of the BSc study program “Natural resources” are reviewed and the training and education for a “Natural Resources Manager” together with the required continuous education is discussed.