A comparative study of hygroscopic moisture content,electrical conductivity and ion chromatography for salt assessment in plasters of historical buildings

It has long been known that highly soluble salts or hydrate-forming salts can damage porous building material. There is a real challenge to provide salt assessment in compliance with good monuments diagnosis and restoration practices. The salts present in the masonry can be analysed qualitatively and quantitatively by means of several techniques. Nowadays, the standard analytical equipment as ion chromatography (IC) found in several laboratories is a reliable method for analysing a large variety of anions and cations in solutions (or building materials water extracts), in order to meet international standards and regulations. However, preliminary study and diagnosis of soluble salt present in monuments do not necessarily require such a precise (SD < 5%) and sensitive (ppm or ppb range) analyses. Some simple-to-use techniques, such as hygroscopic moisture content (HMC) and electrical conductivity (EC) of extracted salt solutions, are widely in use to provide indications on the presence of salts.This paper presents a comparison of salt assessment obtained by IC, HMC and EC methods, and provides the domain of their application to specific questions linked to the damaged building diagnosis and preservation.The comparison of the results obtained by IC, EC and HMC analyses highlights the limits of the EC method in providing quantitative information on soluble salt content. The EC technique seems to require some cautions when used for materials containing other high soluble phases such as portlandite. On the other hand, the HMC technique seems to be very useful in the field of historical masonry investigation since it can provide reliable semi-quantitative distribution of hygroscopic salts.     

Implications of the new National Energy Basic Plan for nuclear waste management in Korea

The Korean National Energy Committee has recently adopted a new National Energy Basic Plan according to which the electricity generated by nuclear power plants is to increase from the current 35.5% of total electricity production to 59% by 2030. This large increase in nuclear power will inevitably accelerate the accumulation of spent fuel; if the direct disposal option is pursued, spent fuel arisings in Korea are expected to exceed 100,000 tHM in 2100. It is estimated that the country will require between 10–22 disposal sites, each with an area equal to the Gyeongju low- and intermediate-level radioactive waste (LILW) disposal site, to accommodate this amount of spent fuel. However, considering Korea's geographic profile, securing this number of sites will be almost impossible, and will ultimately create a serious problem for the sustainability of nuclear energy in the country. In view of this dilemma, this paper recommends that the volume of Korean nuclear waste for disposal be significantly reduced, and offers sodium fast reactor (SFR)-based recycling as a potentially viable solution.     

The effect of cooking on the glucosinolates content in white cabbage

The effect of different cooking times on the GLS content in white cabbage (Brassica oleracea L. var. capitata f. alba) was determined. Cooking of cabbage for 5-30 min caused a gradual decrease in the GLS content. The most efficient reduction of the GLS content (by about 35%) occurred during the first minutes of cooking. As the cooking time was extended by another 5 min, each time the GLS content decreased by 10-15%. Higher losses in indole GLS, as compared to those of aliphatic ones, resulted from more efficient diffusion of those compounds to cooking water. The GLS content in cooking water, irrespective of the cooking time of white cabbage, remained rather stable, whereas the content of indole GLS was between 3.5- and 4-fold higher in comparison to that of aliphatic GLS. Taking into consideration the rate of changes in the content of particular GLS in cabbage and the GLS content in cooking water, it can be stated that glucoiberin was more thermolabile than other GLS.     

Exposure to antibiotics induces expression of the Mycobacterium tuberculosis sigF gene: implications for chemotherapy against mycobacterial persistors

BACKGROUND: Although many studies have investigated macromolecular uptake in the stomach and small intestine, little is known about macromolecular uptake in the colon. AIMS: To investigate the mechanisms involved in the transport of large antigenically intact macromolecules across the proximal and distal colonic epithelium in the rabbit. METHODS: The mucosal to serosal movement of bovine serum albumin (BSA) was examined in modified Ussing chambers under short circuited conditions. The mucosal surface was exposed to varying concentrations of BSA, and after a 50 minute equilibration period, the mucosal to serosal flux of immunologically intact BSA was determined by ELISA. Total BSA flux was determined by the transport of radiolabelled 125I-BSA. RESULTS: Intact BSA transport in proximal and distal colonic tissue showed saturable kinetics. Intact BSA transport in the proximal and distal segment was 7% and 2% of the total 125I-BSA flux respectively. Immunologically intact BSA transport in the distal segment was significantly less than that in the proximal segment. Intact BSA transport in the proximal colon was significantly reduced following treatment with sodium fluoride, colchicine, and tetrodotoxin. Cholinergic blockade had no effect on the uptake of intact BSA. Conclusion: The findings indicate that the transport of intact macromolecules across the proximal and distal large intestine is a saturable process. Further, intact BSA transport in the proximal colon is an energy dependent process that utilises microtubules and is regulated by the enteric nervous system.     

Enhancement of solid dissolution process under the influence of rotating magnetic field

The main objective of this work is to study the effect of rotating magnetic field (RMF) on the dissolution process of NaCl-cylindrical sample. The experimental investigations are provided for the explanation of the influence on the dissolution process of a solid body to surrounding its dilute solution in the experimental set-up with the RMF generator. The analysis indicated the strong influence of the localization NaCl-cylindrical sample on the enhancement of mass transfer process. The mass transfer process under the action of RMF is described by means of the dimensionless equation with the local magnetic Taylor number.     

Modeling of program, erase and retention characteristics of charge-trap gate all around memories

This paper describes the effect of geometry in charge-trap (CT) memory devices. We first theoretically analyze the impact of the curvature radius on the behavior of the gate current in Gate-All-Around devices, and then describe the change to make to planar model in order to fit the cylindrical devices characteristics. This model is used to simulate Nanocrystal and SONOS program, erase and retention behaviors. The dynamics enhancement during program/erase due to the bending of the active region in such cylindrical devices is explained. The scaling perspectives conclude this paper.     

Deformation behavior of cold-rolled and annealed Zr-1.5Nb and Zr-1.5Nb-S alloys

In this study, the effect of sulphur on the deformation behavior of cold rolled and annealed Zr-1.5Nb, Zr-1.5Nb-S alloys were studied. The beneficial effect of sulphur on the strengthening was observed both in the cold rolled and annealed Zr-1.5Nb-S alloys. The loss of ductility was intensified with the addition of sulphur in the annealed Zr-1.5Nb-S alloys in the region of dynamic strain aging, implying the interdependent effect of oxygen and sulphur. The activation volumes, V^∗, for the cold rolled alloys are not much different from those of annealed alloys. The activation volume, V^∗, decreased slightly with the increase of the sulphur content at room temperature and 300 °C. Insensitivity of the activation volume to the dislocation density and the decrease of the activation volume with the addition of sulfur support the suggestion linking the activation volume with the activated bulge of dislocations limited by segregation of oxygen and sulphur atoms. The higher flow stress increase with the addition of sulfur in Zr-1.5Nb alloy of the present study with the higher oxygen content (∼1600 ppm) is compatible with the suggestion of the interdependent strengthening effect of sulfur and oxygen.