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[en] Two methods are described used in on-line sludge analysis, i.e., the method using neutron thermalization and the method based on the detection of prompt gamma radiation. The neutron thermalization method is suitable for the determination of the water content in Fe oxide sludges provided the solid phase has a constant composition and large-volume sampling is carried out. The prompt gamma detection method is suitable for the simultaneous multi-element determination of the composition of water sludges containing iron, copper, zinc and sulfur oxides and is independent of the sludge flow rate. (J.P.)
[en] Highlights: • The HOC-contaminated soil treatment using soil slurry bioreactors is reviewed. • The main HOC-removal mechanisms, such as biodegradation, gas-liquid and solid-liquid transfer are identified and explained. • HOC removal depends on the pollutant type and nature, the soil or sediment characteristics and the operational parameters. • Volatilization and oxygen transfer are the less studied processes in these systems. • Research directions regarding bioslurry technology are highlighted. - Abstract: Hydrophobic organic compound (HOC)-contaminated soils are a great environmental and public health concern nowadays. Further research is necessary to develop environmental friendly biotechnologies that allows public and private sectors to implement efficient and adaptable treatment approaches. Aerobic soil-slurry bioreactor technology has emerged as an effective and feasible technique with a high remediation potential, especially for silt and clay soil fractions, which often contain the highest pollutant concentration levels and are usually difficult to remove by implementing conventional methods. However, the mechanisms involved in the HOC removal in bioslurry reactor are still not completely understood. Gas-liquid and solid-liquid mass transfer, mass transport and biodegradation phenomena are the main known processes taking place in slurry bioreactors. This review compiles the most up-to-date information available about these phenomena and tries to link them, enlightening the possible interactions between parameters. It gathers the basic information needed to understand the complex bioremediation technology and raises awareness of some considerations that should be made.
[en] A plant that is particularly suitable for treating clarified sludge is described. The container for holding the radiation sources is provided with a circular upper end and is closed by a common closure member. This member is, in turn, clamped onto the container by a holder via a bayonet connection. A clamping tool is also provided to remove the holder and permit replacement of the radiation sources. This tool also enables the holder and closure member to be pre-stressed before removing the holder and after re-asssembly of the holder
[en] The purpose of this invention is to make a vessel which allows a safe and simple method of transporting and emptying radioactive liquids which have a high content of solids likely to form sediments. This object is achieved by installing in the vessel a submersible pump which can be moved vertically up and down and which can be used for both the churning up and emptying actions. (K)
[en] A model of the associated layer on the surface of nanoparticles in a fluid, which makes up mechanically integrated inclusions with them, has been proposed. Such inclusions can primarily be considered as solid particles with a diameter larger than their nucleus. This can be interpreted as the effective increase in the volume concentration of primary particles, which makes it possible to adapt the existing Bachelor formula to describe the results of measurements of the nano fluid viscosity. The inevitability of the agglomeration of nanoparticles in view of the associated fluid layer being present on their surface has also been demonstrated. It has been shown that the effective volume concentration depends on the size of primary nanoparticles and the degree of their agglomeration. Furthermore, data have been presented according to which the associated-layer thickness for particles with a diameter under 20 mm becomes dependent on the nanoparticle size. (authors)
[en] Slurry walls have become an accepted subsurface remediation technique to contain contaminated zones. However, situations develop where conventional slurry wall excavation techniques are not suitable. The use of conventional containment wall construction methods may involve removal and disposal of contaminated soils, stability concerns and the risk of open excavations. For these reasons, other installation techniques have received further consideration. Deep Soil Mixing (DSM) has emerged as a viable alternative to conventional slurry wall techniques. In situations dictating limited soil removal for contamination or stability concerns, or where space is a limitation, DSM can be used for installation of the barrier. Proper installation of a DSM wall requires sufficient monitoring and sampling to evaluate the continuity, mixing effectiveness, permeability and key into the confining layer. This paper describes a case study where DSM was used to cross major highways to avoid open excavation, and along slopes to reduce stability concerns. The DSM barrier was tied to an existing conventional slurry wall that had been installed in more stable areas without highway traffic
[en] Highlights: • Recent studies conducted on use of nanofluids in heat exchangers are reviewed. • Fascinating aspects on combination of nanofluid with heat exchanger are presented. • Challenges and opportunities for future research are addressed and discussed. - Abstract: Heat exchangers have already proven to be important devices for thermal systems in many industrial fields. In order to improve the efficacy of heat exchangers, nanofluids are recently employed as coolants in them. Regarding unique characteristics of nanofluids, research studies in this area have witnessed a remarkable growth. This paper reviews and summarizes recent investigations conducted on use of nanofluids in heat exchangers including those carried out on plate heat exchangers, double-pipe heat exchangers, shell and tube heat exchangers, and compact heat exchangers. Meanwhile, some fascinating aspects about combination of nanofluids with heat exchangers are introduced. In addition, the challenges and opportunities for future research are presented and discussed.
[en] The erosive wear performance of AA5083 and AA1050 has been investigated under dry and slurry erosion condition. The current work insights the erosive wear behaviour of Al alloys by changing the impact velocity and impingement angle. AA5083 exhibited remarkable erosion resistance compared to AA1050 by a factor of 2.5 to 3 in both the tests. The surface roughness of the eroded surface for impingement angle 15, 60° was an average of 450, 170 μm respectively for dry and slurry erosion test. Hardness of the eroded surface after the erosion test was measured to be 128.6 and 111.5 Hv for AA5083 and 63.9 and 52.9 Hv for AA1050 respectively for dry and slurry erosion. Wear surface studies reveals that cutting as well as abrasion grooves were dominant at lower impingement angle for both the tests. As the impingement angle increased, the material removal process was tuned by ploughing and formation of a crater in dry erosion and cracking in slurry erosion was witnessed. The subsurface study reveals that the affected region beneath the wear surface was an average of 40 and 25 μm for AA1050 and AA5083. Erosion data was correlated with the published empirical erosion model to analyse the dependence of the impingement angle. (paper)