Water In Various Forms Research Articles

Benchmarks of graph invariants for hydrogen-bond networks in water clusters of different topology

The diversity of the various forms of water stems from systems of hydrogen bonds. Cooperative behaviour of hydrogen-bond networks gives rise to unique properties of water systems. A number of approaches to understand and model the collective behaviour of hydrogen bonds and predict their properties on the basis of a small number of calculations have been put forward. Among them, the concept of graph invariants provides most general descriptors for hydrogen-bond networks, which are routinely used to predict properties of water systems. In the present work, we examine the formalism of graph invariants and propose its modification which may be beneficial for water structures with defects. To benchmark graph invariants, we carried out quantum-chemical calculations of more than 107 water clusters with different hydrogenbond configurations. The quality of the approximation is studied as a function of the type of graph invariant and its order. The results demonstrate that the method is applicable only to cage-like structures without significant strains.

The “Barbarous Game”: Entrudo and Its Critics in Rio de Janeiro, 1810s–1850s

Abstract This article examines the pre-Lenten festivities labeled entrudo in early nineteenth-century Rio de Janeiro and traces the efforts to repress them, which enjoyed a measure of success by the mid-1850s. During this period, the predominant form of pre-Lenten revelry involved various forms of water play that transgressed the boundaries between the sexes but tended to respect other social hierarchies. After independence, authorities and members of a self-proclaimed “civilized” elite sought to repress what they condemned as a “barbarous” game. These efforts obtained some success in the 1840s and 1850s as masked balls and parading by elite carnival societies came to dominate middle- and upper-class forms of celebration, although entrudo persisted longer among the lower classes. Based on travelers' accounts and the extensive newspaper debates about entrudo and its repression, this article analyzes a major cultural change among the Brazilian capital's elite.

Fate and Risk Assessment of Perfluoroalkyl Substances (PFASs) in Water Treatment Plants and Tap Water in Bangkok, Thailand

Perfluoroalkyland Polyfluoroalkyl Substances (PFASs), especially Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonate (PFOS), were found to contaminate the natural water sources serving as a raw material in producing tap water. The main purpose of this study was to measure the quantities of PFASs in both conventional and advanced water treatment processes, and of the PFASs contaminated tap water in various forms, with comparison made between tap water and water passing through drinking devices. It was found from the investigation that the conventional treatment process using coagulation, sedimentation, filtration and chlorination was incapable of removing PFASs, and that the concentration of effluent increased more than 27% compared to the influent. On the contrary, advanced water treatment process using GAC filter and RO was able to remove more than 86% of PFASs. The tap water was found to contain PFASs at 0.58-1.15 ng/L. However, a comparison between the average of the water passing through drinking devices and direct faucet showed insignificant difference, but the concentration of PFASs decreased by a small amount when passing a filter-equipped device.

Laser scanning microscopy in cryobiology.

Laser scanning microscopy is emerging as a powerful imaging tool in cryobiology. The basic microscopy system can be combined with various imaging modalities including Raman spectroscopy, fluorescence correlation spectroscopy, fluorescence lifetime imaging, or multiphoton imaging. Multiphoton imaging can be used to study intracellular ice formation at the subcellular level. A Raman imaging modality can be used for chemical mapping of frozen samples. A Raman spectrum gives information about characteristic molecular vibrations of specific groups in molecules. Raman images can be used to determine the localization of intra- and extracellular constituents and the various forms of water in freeze-concentrated solutions. Spectra can be collected during freezing and thawing of a sample using a temperature-controlled sample holder. In this chapter, various advanced cryoimaging methods are described. Special emphasis is given on the different imaging modalities that can be used to study the various aspects of cryopreservation.

Scientific evidence-based effects of hydrotherapy on various systems of the body.

The use of water for various treatments (hydrotherapy) is probably as old as mankind. Hydrotherapy is one of the basic methods of treatment widely used in the system of natural medicine, which is also called as water therapy, aquatic therapy, pool therapy, and balneotherapy. Use of water in various forms and in various temperatures can produce different effects on different system of the body. Many studies/reviews reported the effects of hydrotherapy only on very few systems and there is lack of studies/reviews in reporting the evidence-based effects of hydrotherapy on various systems. We performed PubMed and PubMed central search to review relevant articles in English literature based on “effects of hydrotherapy/balneotherapy” on various systems of the body. Based on the available literature this review suggests that the hydrotherapy has a scientific evidence-based effect on various systems of the body.

Water and other volatiles on the moon: A review

This paper presents a review of research findings on the various forms of water on the Moon. First, this is the water of the Moon’s interior, which has been detected by sensitive mass spectrometric analysis of basaltic glasses delivered by the Apollo 15 and Apollo 17 missions. The previous concepts that lunar magmas are completely dehydrated have been disproved. Second, this is H2O and/or OH in a thin layer (a few upper millimeters) of the lunar regolith, which is likely a result of bombardment of the oxygen contained in the lunar regolith with solar wind protons. This form of water is highly unstable and quite easily escapes from the surface, possibly being one of the sources of the water ice reservoirs at the Moon’s poles. Third, this is water ice associated with other frozen gases in cold traps at the lunar poles. Its possible sources are impacts of comets and meteorites, the release of gas from the Moon’s interior, and solar wind protons. The ice trapped at the lunar polars could be of practical interest for further exploration of the Moon.

Method for quantitative determination of various forms of water in biologically active substances

The content of water in substances and preparations based on biologically active materials determines to a considerable extent their biopharmaceutical properties and stability. A new method has been developed for separate quantitative determination of water in various bound forms in biologically active substances isolated from raw plant materials. Dihydroquercetin is used as an example to demonstrate that the proposed method is capable of determining water fractions with various degrees of binding in a sample.

Water Loss Assessment and Remediation in South and Southeast Asia

One of the major challenges facing water utilities around the world but especially in Low and Middle Income Countries (LAMIC) is the high level of water losses either through physical losses (leakage) or commercial losses (customer meter under-registration and theft of water in various forms). This difference between the amount of water put into the distribution system and the amount of water billed to consumers is known as “Non-Revenue Water” (NRW). Levels of NRW in South and Southeast Asia are among the highest in the world. This paper will give an update of the general NRW situation in the various countries and the ongoing remediation measures.

Towards the complete understanding of water by a first-principles computational approach

The current state-of-the-art in theoretical investigations of water is reviewed. Emphasis is on first-principles approaches, i.e., those not using any experimental information to make predictions. These approaches have substantially advanced in the past few years, to the point of providing the currently most accurate description of the various forms of water, more accurate than empirical methods which fit parameters of water models to observations. The advantage of a first-principles approach is that it allows a deeper physical insight in the properties of water and therefore achieves a better understanding of this unusual medium.

Concentration of various forms of water in silica precipitated from a hydrothermal solution

The physicochemical properties of the surface of silica precipitated from a hydrothermal solution have been studied. The concentration of physically adsorbed water, and the net concentration of surface and bulk (internal) hydroxyl groups have been found by low-temperature adsorption of nitrogen and thermogravimetric data. The concentration of internal silicone (internal water) under different temperatures of the silica specimens under study has been estimated from the difference between the net concentration and the Zhuravlev physicochemical constants. The type of noncrystalline silica containing substantial amounts of internal water has been identified. The difference in mechanisms involved in internal and surface water extraction has been established.

X-Ray Study of Synthetic Alunite

Alunite, KΑl3(SO4)2(OH)6, crystallizing in space group R3m, is a mineral identified in numerous sites in the world. It belongs to a family of structurally related substances described by a general formula AB3(SO4)2(OH)6, where A may become Na+, K+, H3O+, Nu+4 or Ag+ and B either Al3+ or Fe3+ Natural and synthetic alunites have been subjects of extensive stuctural investigations employing single-crystal and powder X-ray techniques, NMR and other methods [1-16]. One of the reasons of this interest is a possibility of industrial applications of alunite and related minerals: The composition of the natural alunite depends on the formation conditions and on the environment while that of a synthetic one is influenced by the way of synthesis. A number of recent papers [5, 6, 9, 13-16] deal with the problem of the composition of natural and synthetic alunite. The existing synthesis methods yield alunite of composition often differing from the stoichiometric one; the reported differences concern the deficiency in K and Al as well as the presence of excess water. In our work the term excess refers to various forms of water (e.g. H3O+, H2O) which may be present in alunite unit-cell except for stoichiometric OHions. Dne to differences in synthesis method and observed differences in composition, the published unit-cell dimensions vary within a range of about 0.05 Α

Nitrogen Budget for the Rotifer Brachionus plicatilis

AbstractNitrogen ingested by the rotifer, Brachionus plicatilis (S type) is balanced by gain in body nitrogen (including reproduction), soluble excreted nitrogen, and nitrogen as egested feces. Every term in the budget was estimated independently, and measured as directly as possible. A comparison of the observed and calculated nitrogen as egested feces yielded a satisfactory result.The nitrogen ingested by the rotifer was distributed as follows: 15.6% for growth and reproduction, 42.0% for metabolic excretion, and 42.4% as feces. From these results, it was concluded that a large proportion (84%) of the nitrogen ingested by the rotifer is transferred to water in various forms and may cause deterioration of the water quality.

The type three ordinary chondrities: A review

The ordinary chondrites are the largest group of meteorites, and the type 3 ordinary chondrites are those which experienced only very mild parent metamorphism; their study provides a unique means of studying the first solid material to from in the early solar system which is either free from the effects of mild metamorphism, or in which the effects of mild metamorphism can be distinguished from primary, nebular effects. In this paper we list all known type 3 ordinary chondrites and references to their study, their compositional data and data relating to the metamorphic history. We review current theories on their formation and the effects of metamorphism, with emphasis on quantitative considerations. Studies on the thermoluminescence properties of these meteorites, which have provided many new insights into their metamorphic history, are reviewed. Some of the least metamorphosed meteorites show evidence for aqueous alteration, which provides a link between the type 3 ordinary chondrites and objects containing water in various forms the carbonaceous chondrites, comets and planets with ‘wet’ mantles.

EFFECTS OF PRECIPITATION ON CROP INSECTS

AbstractA review and analysis of the literature showed that precipitation, or its absence, can regulate the numbers of or the damage by insect pests of annual crops in Canada in essentially four main ways: as soil moisture, when the insects are in the ground; as a mechanical factor that impinges directly on them when they are exposed; through its effects on foodplants; and through its effects on natural enemies of the pests. Though any one pest species may be influenced by two or more of these processes and in different ways by each depending on the stage of its life cycle that is affected, usually only one way is significant. Precipitation is so far of little value in forecasting pest situations reliably, but water in various forms has much potential for use as a pest control agent.