Exploring the differences between forward osmosis and reverse osmosis fouling

A comparison of alginate fouling in forward osmosis (FO) with that in reverse osmosis (RO) was made. A key experimental finding, corroborated by membrane autopsies, was that FO is essentially more prone to fouling than RO, which is opposite to a common claim in the literature where deductions on fouling are often based solely on the water flux profiles. Our theoretical analysis shows that, due to a decrease in the intensity of internal concentration polarization (ICP), and thus an increase in the effective osmotic driving force during FO fouling tests, the similarity of experimental water flux profiles for FO and RO is in accordance with there being greater fouling in FO than RO. The specific foulant resistance for FO was also found to be greater than that for RO. Possible explanations are discussed and these include the influence of reverse solute diffusion from draw solution. Whilst this explanation regarding specific foulant resistance is dependent on the draw solution properties, the finding of greater overall foulant accumulation in FO is considered to be a general finding. Additionally, the present study did not find evidence that hydraulic pressure in RO plays a critical role in foulant layer compaction. Overall this study demonstrated that although FO has higher fouling propensity, it offers superior water flux stability against fouling. For certain practical applications this resilience may be important

On the absence of appreciable half-life changes in alpha emitters cooled in metals to 1 Kelvin and below

The recent suggestion that dramatic changes may occur in the lifetime of alpha and beta decay when the activity, in a pure metal host, is cooled to a few Kelvin, is examined in the light of published low temperature nuclear orientation (LTNO) experiments, with emphasis here on alpha decay. In LTNO observations are made of the anisotropy of radioactive emissions with respect to an axis of orientation. Correction of data for decay of metallic samples held at temperatures at and below 1 Kelvin for periods of days and longer has been a routine element of LTNO experiments for many years. No evidence for any change of half life on cooling, with an upper level of less than 1%, has been found, in striking contrast to the predicted changes, for alpha decay, of several orders of magnitude. The proposal that such dramatic changes might alleviate problems of disposal of long-lived radioactive waste is shown to be unrealistic.Comment: 27 pages, 12 figures, accepted for publication in Nucl.Phys.A. Revised version, including quantitative analysis of the sensitivity of nuclear orientation experiments, discussed in this work, to changes of alpha-decay lifetimes in metals at low temperatures. Conclusions remain unchange

Fouling and Cleaning in Osmotically Driven Membranes

Fouling is a phenomenon that occurs in all membrane processes. It is a complex problem, which limits the full operation of this technology. Fouling in pressure-driven membranes (PDMs) has been studied extensively, and the occurrence is well understood in that methods of mitigation have been proposed; however, limitations still occur for their full implementation. The use of osmotically driven membranes (ODMs) for water treatment is an emerging technology, which has shown some advantages such as low hydraulic pressure operation, high solute rejection and high recovery over PDMs. However, like in PDMs, fouling still presents a challenge. This chapter is aimed at evaluating the impact of fouling on the ODM performance, exploring the factors and mechanisms governing the fouling behaviour, developing approaches for mitigating fouling, elucidating the effect of membrane fouling and providing mitigation strategies as well as the causes of fouling in ODMs

Spin dynamics and disorder effects in the S=1/2 kagome Heisenberg spin liquid phase of kapellasite

We report $^{35}$Cl NMR, ESR, $\mu$SR and specific heat measurements on the $S=1/2$ frustrated kagom\'e magnet kapellasite, $\alpha-$Cu$_3$Zn(OH)$_6$Cl$_2$, where a gapless spin liquid phase is stabilized by a set of competing exchange interactions. Our measurements confirm the ferromagnetic character of the nearest-neighbour exchange interaction $J_1$ and give an energy scale for the competing interactions $|J| \sim 10$ K. The study of the temperature-dependent ESR lineshift reveals a moderate symmetric exchange anisotropy term $D$, with $|D/J|\sim 3$%. These findings validate a posteriori the use of the $J_1 - J_2 - J_d$ Heisenberg model to describe the magnetic properties of kapellasite [Bernu et al., Phys. Rev. B 87, 155107 (2013)]. We further confirm that the main deviation from this model is the severe random depletion of the magnetic kagom\'e lattice by 27%, due to Cu/Zn site mixing, and specifically address the effect of this disorder by $^{35}$Cl NMR, performed on an oriented polycrystalline sample. Surprisingly, while being very sensitive to local structural deformations, our NMR measurements demonstrate that the system remains homogeneous with a unique spin susceptibility at high temperature, despite a variety of magnetic environments. Unconventional spin dynamics is further revealed by NMR and $\mu$SR in the low-$T$, correlated, spin liquid regime, where a broad distribution of spin-lattice relaxation times is observed. We ascribe this to the presence of local low-energy modes.Comment: 15 pages, 11 figures. To appear in Phys. Rev.

On Recognizing Transparent Objects in Domestic Environments Using Fusion of Multiple Sensor Modalities

Current object recognition methods fail on object sets that include both diffuse, reflective and transparent materials, although they are very common in domestic scenarios. We show that a combination of cues from multiple sensor modalities, including specular reflectance and unavailable depth information, allows us to capture a larger subset of household objects by extending a state of the art object recognition method. This leads to a significant increase in robustness of recognition over a larger set of commonly used objects.Comment: 12 page

Regional specialisation in a transition country - Hungary

There has been a growing interest on regional issue over the last decade stimulated by increasing policy about reducing regional inequalities resulted from economic integration. In the last decade the free trade affected the post-communist countries, and predominantly among them those, which had a maturated level of stability, economical development and their geopolitical situation is favoured. Hungary is a considerable area to study the pattern of “new economic geography”. In paper we identify, explain and forecast the impact of globalisation, on regional and small unit /local level. The key question for the future development of the world economy is how will the economy choose its new place? Are regional inequalities likely to narrow or widen? And how the EU enlargement likely to lead to the relocation of industries? The regional indicators are verifying on NUTS level III. the regional concentration and describe the shifted new regional structure. The aim of the project to check the regularities and irregularities of the variables in an accession country. The relevant findings will be discussed concerning the policy. The questions to be addressed, which changes may be identified due to the trade reorientation towards the EU? Which new location an relocation of industrial activity may be identified? What types of regions are likely to be winners and losers who regulate the regulators? About the adaptation process we will draft some policy orientation for decision makers.

In-situ electron microscopy investigation of ferroelectric domain switching kinetics

Due to their ultra-high piezoelectricity, pyroelectric properties, mechanical/electrical hysteresis properties and their possessing of non-volatile polarization states, ferroelectric materials have been used in various electronic devices, including various sensors, actuators, transducers, micromotors, and non-volatile memories. The mechanical, electrical, electromechanical, and thermoelectric properties are crucial factors for device applications of ferroelectric materials. These properties are particularly sensitive to the change of the embedded microscopic structures. Therefore, the mechanical and electrical characterisation of ferroelectric materials and the observation of their microstructural evolution under external stimuli are necessary for understanding their unique properties. However, this is not an easy task because of the difficulty of mechanical and electrical testing of nano/microscale materials. Various techniques have been used to investigate the mechanical and electrical behaviours of ferroelectric materials, among which the in-situ transmission electron microscopy is one of the most effective techniques. This thesis aims to combine state-of-the-art in-situ transmission electron microscopy techniques, the scanning transmission electron microscopy high-angle annular dark-field imaging technique, and phase-field modelling to investigate microstructural evolution in ferroelectric materials under different external stimuli. One of the ultimate goals of this research is to improve the performance of non-volatile ferroelectric memory devices