Admixture Of Water Research Articles

Ocean circulation and freshwater pathways in the Arctic Mediterranean based on a combined Nd isotope, REE and oxygen isotope section across Fram Strait

The water masses passing the Fram Strait are mainly responsible for the exchange of heat and freshwater between the Nordic Seas and the Arctic Ocean (the Arctic Mediterranean, AM). Disentangling their exact sources, distribution and mixing, however, is complex. This work provides new insights based on a detailed geochemical tracer inventory including dissolved Nd isotope (εNd), rare earth element (REE) and stable oxygen isotope (δ18O) data along a full water depth section across Fram Strait.We find that Nd isotope and REE distributions in the open AM primarily reflect lateral advection of water masses and their mixing. Seawater-particle interactions exert important control only above the shelf regions, as observed above the NE Greenland Shelf. Advection of northward flowing warm Atlantic Water (AW) is clearly reflected by an εNd signature of −11.7 and a Nd concentration ([Nd]) of 16pmol/kg in the upper ∼500m of the eastern and central Fram Strait. Freshening and cooling of the AW on its way trough the AM are accompanied by a continuous change towards more radiogenic εNd signatures (e.g. −10.4 of dense Arctic Atlantic Water). This mainly reflects mixing with intermediate waters but also admixture of dense Kara Sea waters and Pacific-derived waters. The more radiogenic εNd signatures of the intermediate and deep waters (reaching −9.5) are mainly acquired in the SW Nordic Seas through exchange with basaltic formations of Iceland and CE Greenland. Inputs of Nd from Svalbard are not observed and surface waters and Nd on the Svalbard shelf originate from the Barents Sea. Shallow southward flowing Arctic-derived waters (<200m) form the core of the East Greenland Current above the Greenland slope and can be traced by their relatively radiogenic εNd (reaching −8.8) and elevated [Nd] (21–29pmol/kg). These properties are used together with δ18O and standard hydrographic tracers to define the proportions of Pacific-derived (<∼30% based on Nd isotopes) and Atlantic-derived waters, as well as of river waters (<∼8%). Shallow waters (<150m) on the NE Greenland Shelf share some characteristics of Arctic-derived waters, but exhibit less radiogenic εNd values (reaching −12.4) and higher [Nd] (up to 38pmol/kg) in the upper ∼100m. This suggests local addition of Greenland freshwater of up to ∼6%. In addition to these observations, this study shows that the pronounced gradients in εNd signatures and REE characteristics in the upper water column provide a reliable basis for assessments of shallow hydrological changes within the AM.

The chemistry and isotopic composition of waters in the low-enthalpy geothermal system of Cimino-Vico Volcanic District, Italy

Geothermal energy exploration is based in part on interpretation of the chemistry, temperature, and discharge rate of thermal springs. Here we present the major element chemistry and the δD, δ18O, 87Sr/86Sr and δ11B isotopic ratio of groundwater from the low-enthalpy geothermal system near the city of Viterbo in the Cimino-Vico volcanic district of west-Central Italy. The geothermal system hosts many thermal springs and gas vents, but the resource is still unexploited. Water chemistry is controlled by mixing between low salinity,HCO3-rich fresh waters (<24.2°C) flowing in shallow volcanic rocks and SO4-rich thermal waters (25.3°C to 62.2°C) ascending from deep, high permeability Mesozoic limestones. The (equivalent) SO4/Cl (0.01–0.02), Na/Cl (2.82–5.83) and B/Cl ratios (0.02–0.38) of thermal waters differs from the ratios in other geothermal systems from Central Italy, probably implying a lack of hydraulic continuity across the region. The δ18O (−6.6‰ to −5.9‰) and δD (−40.60‰ to −36.30‰) isotopic composition of spring water suggest that the recharge area for the geothermal system is the summit region of Mount Cimino. The strontium isotope ratios (87Sr/86Sr) of thermal waters (0.70797–0.70805) are consistent with dissolution of the Mesozoic evaporite-carbonate units that constitute the reservoir, and the ratios of cold fresh waters mainly reflect shallow circulation through the volcanic cover and some minor admixture (<10%) of thermal water as well. The boron isotopic composition (δ11B) of fresh waters (−5.00 and 6.12‰) is similar to that of the volcanic cover, but the δ11B of thermal waters (−8.37‰ to −4.12‰) is a mismatch for the Mesozoic reservoir rocks and instead reflects dissolution of secondary boron minerals during fluid ascent through flysch units that overlie the reservoir. A slow and tortuous ascent enhances extraction of boron but also promotes conductive cooling, partially masking the heat present in the reservoir. Overall data from this study is consistent with previous studies that concluded that the geothermal system has a large energy potential.

Heat transfer under high-power heating of liquids. 4. The effect of water admixtures on the heat transfer in superheated hydrocarbons

The a priory unknown peculiarities of heat transfer in superheated hydrocarbons with water traces have been studied experimentally. The approach was based on the relative version of the method of controlled pulse heating of a wire probe at constant current mode. The pulse duration was varied in the range of 1–120ms. A region of probe temperature rise was limited from above by the value of spontaneous boiling-up temperature of a substance. The objects of study were n-hexane, n-decane, and n-hexadecane. The water content was varied in the range from 5ppm (initial sample) to 35ppm (watered sample). A sharp increase in the heat transfer intensity for watered sample with respect to that of initial one has been revealed. The observed effect was manifested solely at temperatures close to the values of boiling-up temperature of watered sample.

Evaluation of the Carbon Dioxide Uptake of Slag-Blended Concrete Structures, Considering the Effect of Carbonation

During the production of concrete, cement, water, aggregate, and chemical and mineral admixtures will be used, and a large amount of carbon dioxide will be emitted. Conversely, during the decades of service life of reinforced concrete structures, carbon dioxide in the environment can ingress into concrete and chemically react with carbonatable constitutes of hardened concrete, such as calcium hydroxide and calcium silicate hydrate. This chemical reaction process is known as carbonation. Carbon dioxide will be absorbed into concrete due to carbonation. This article presents a numerical procedure to quantitatively evaluate carbon dioxide emissions and the absorption of ground granulated blast furnace slag (GGBFS) blended concrete structures. Based on building scales and drawings, the total volume and surface area of concrete are calculated. The carbon dioxide emission is calculated using the total volume of concrete and unit carbon dioxide emission of materials. Next, using a slag blended cement hydration model and a carbonation model, the carbonation depth is determined. The absorbed carbon dioxide is evaluated using the carbonation depth of concrete, the surface area of concrete structures, and the amount of carbonatable materials. The calculation results show that for the studied structure with slag blended concrete, for each unit of CO2 produced, 4.61% of carbon dioxide will be absorbed during its 50 years of service life.

Production of nitric/nitrous oxide by an atmospheric pressure plasma jet

Absolute densities of nitrous species were studied in an atmospheric pressure RF plasma jet. The measurement of NO and N2O densities has been performed mainly by means of ex situ quantum-cascade laser absorption spectroscopy via a multi-pass cell in Herriot configuration.The dependence of the species’ production on individual parameters such as power, flow and oxygen, nitrogen and water admixture is shown. NO and N2O densities are found to increase with absorbed power, while an increase in the gas flow induces a decrease of these densities due to a reduction in residence time of the gas in the plasma. Actually, a change of these two parameters, absorbed power and gas flow, induces a variation of energy density. The higher energy density, the higher NO and N2O densities.The NO and N2O densities are strongly gas mixture dependent. A change of that parameter allows to choose between a NO-rich or a N2O-rich regime. NO and N2O densities increase as a function of the N2 admixture, while increasing oxygen, above a minimum value, reduces the densities of both NO and N2O. When adding water instead of oxygen to the gas mixture the reduction in the NO density is much less.For maximal NO and N2O formation a ratio of about He/N2/O2 = 99.5/0.36/0.07 is found to be the most efficient in the μ-APPJ. However, it was found that the absorbed power in the plasma always reduces with increasing admixtures.The validation of the results obtained with quantum-cascade absorption spectroscopy with mass spectrometry shows how the two measurement techniques can complement each other.Finally a comparison of our results and others works is presented.

Enhancement the Strength of Pervious Concrete with Different Water Cement Ratio and Admixture

Enhancement the Strength of Pervious Concrete with Different Water Cement Ratio and Admixture

The thermodynamic balance of the Weddell Gyre

AbstractThe thermodynamic balance of the Weddell Gyre is assessed from an inverse estimate of the circulation across the gyre's rim. The gyre experiences a weak net buoyancy gain that arises from a leading‐order cancelation between two opposing contributions, linked to two cells of water mass transformation and diapycnal overturning. The lower cell involves a cooling‐driven densification of 8.4 ± 2.0 Sv of Circumpolar Deep Water and Antarctic Bottom Water near the gyre's southern and western margins. The upper cell entails a freshening‐driven conversion of 4.9 ± 2.0 Sv of Circumpolar Deep Water into lighter upper ocean waters within the gyre interior. The distinct role of salinity between the two cells stems from opposing salinity changes induced by sea ice production, meteoric sources, and admixture of fresh upper ocean waters in the lower cell, which contrasts with coherent reductions in salinity associated with sea ice melting and meteoric sources in the upper cell.

Experimental investigation of the utilization of quarry dust for the production of microcement-based building elements by self-flowing molding casting

The management and disposal of fine by-products produced by the aggregate industry, ready-mix concrete and asphalt concrete installations (also known as filler or quarry dust), emerges as a major environmental problem of quarrying and construction sector. Even though considerable research has been undertaken for the utilization of this fine by-product in several applications, it still remains under-utilized, while its disposal and stabilization is also problematic due to resulting emissions of airborne particle pollutants. In this study the production of self-flowing castable cement-based building elements incorporating high amounts of quarry dust was investigated in laboratory scale. Quarry dust, microcement, water and concrete admixtures were mixed and casted in steel molds for the production of the specimens. The initial study of mixtures composition was based on the Andreassen particle packing model, while the final mix design was determined via Box–Behnken fractional factorial design of experiments, in combination with the response surface method. The compressive strength and water absorption values of hardened specimens exceed the relevant technical requirements currently in force, regarding load-bearing as well as decorative building elements, thus opening a new promising field for the utilization of this by-product.

Effect of Coarse Aggregate size on strength of high performance concrete

The development of new methodologies for manufacturing high performance concrete has led to massive increase in its usage worldwide. The higher strength development in concrete has increased the construction of skyscraper, bridges and special structures. Apart from higher strength and better performance the usage of this concrete also lends technical and economical viability to the entire project. The main criteria of making high strength concrete are to reduce the water content and increase the cement proportions. This however leads to reduced workability which can be overcome by the use of different mineral admixtures like rice husk ash, silica fume and fly ash apart from chemical admixtures. In our study, an attempt has been made to determine the effect of varying size of aggregate on high strength concrete using silica fume with and without fly ash. The concrete was manufactured using usual ingredients like cement, coarse aggregates, fine aggregates, water, and mineral admixture in the form of silica fume and fly ash and super plasticizer. Three sizes of coarse aggregates i.e, 10 mm, 12.5mm and 16mm with two types of fine aggregates with fineness modulus 2.65 and 2.88 were used in concrete. The percentage of silica fume and fly ash that replaced cement by weight was 7.5% and 10% respectively. It was concluded that concrete made from 10 mm coarse aggregate and with fine aggregate of fineness modulus 2.88 with silica fume showed higher compressive strength at 28 day curing.

Reaction of thiols and organic disulfides with iron group metals and their oxides

The reactivity of individual BuSH, DdSH (Dd is dodecyl), BnSH (Bn is benzyl), PhSH, and Pr2S2 toward iron group metals under static conditions (without mechanical activation of reaction) and dynamic conditions (with mechanical activation of reaction) was determined. Under static conditions, only BnSH and PhSH are reactive toward iron group metals, while DdSH, BnSH, PhSH, and Pr2S2 are reactive under dynamic conditions. It was shown that oxygen and water admixtures under static conditions favor the formation of iron group metal thiolates and their effect decreases from iron to nickel. The ability of iron group metals to form thiolates when reacted with Pr2S2 increases from iron to nickel.

Fabrication of a superhydrophobic surface on copper foil based on ammonium bicarbonate and paraffin wax coating

A simple and low cost approach was developed to fabricate a superhydrophobic surface on copper foil. The oxidation and etching of the copper foil surface were promoted in NH4HCO3 solution using a water and ethanol admixture as a component solvent. After 28 h in this solution, a hydrophilic rough surface structure was obtained on the copper foil surface. With modification using a paraffin wax coating, the hydrophilic rough copper surface changed to become hydrophobic or superhydrophobic. The surface morphology and wettability were characterized by scanning electron microscopy (SEM) and contact angle measurements, respectively. When the optimum concentration of paraffin wax was about 2 g L−1, its water contact angle could reach about 152 ± 1.5° and its sliding angle was around 7°. The formation mechanism of the rough copper surface was also explored in detail. Both the experimental process and the material are environmentally friendly.

Effect of the content of salt admixtures on integral characteristics of evaporation of water drops moving through high-temperature gas media

Experimental research on the influence of the content of typical salt admixtures in water on integral characteristics of its evaporation while moving through a high-temperature gas medium was carried out using NaCl nanopowder. Experiments were conducted with single large (more than 1 mm) drops and an aggregate of (more than one hundred) small (under 0.3 mm) water droplets moving through a channel filled with high-temperature combustion products. Conditions were determined under which the content of salt admixtures in water has a strong effect (the decrease of mass changes several times) on the intensity of evaporation of the latter in the region of hightemperature gases.

Predicting Compressive Strength of Concrete

This paper deals with development of regression models for prediction of compressive strength of concrete. The compressive strength of concrete is predicted using four variables, namely, water-binder ratio, fine aggregate-binder ratio, coarse aggregate-binder ratio and binder content. Linear regression models have been developed for variations in fly ash replacements (0 and 15 percent), Zones of aggregates (A, B and C) and curing ages (28, 56 and 91 days). An effort has also been made to modify the linear models using a two step approach. First step is to develop quadratic models (termed as full models) by identifying the suitable combinations of the four variables described above. The second step is to select the best minimal subset of the predictors in full models using Mallow's Cp statistic. The proposed quadratic regression models yielded coefficient of determination R 2 ≥ 0.99 in almost every case except for concrete with Zones A and B of aggregates without fly ash for 91 days curing period and for concrete with Zone C of aggregates without fly ash for 56 days curing period. Concrete is a strong building material composed of sand, gravel, cement and water. Additional admixtures are also added sometimes to enhance certain properties of fresh or hardened concrete. In the construction industry, among the various properties of the concrete determination of compressive strength has received a large amount of attention because concrete is primarily meant to withstand compressive stresses. The compressive strength of concrete is controlled by proportioning of cement, coarse and fine aggregates, water and various admixtures. Prediction of concrete compressive strength has been an active area of research and a considerable number of studies have been carried out in this direction. Many attempts have been made to develop a suitable mathematical model which is capable of predicting compressive strength of concrete at various ages with acceptable accuracy. Multiple regression models have been used by researchers to improve accuracy of predictions of concrete compressive strength. Nipatsat and Tangtermsirikul (1) developed equations for estimating compressive strength of concrete containing fly ash with curing ages from 3 days up to 1 year. Kazberuk and Lelusz (2) proposed regression models to predict compressive strength of concrete with fly ash replacement percentages up to 30%. Namyong et al. (3) proposed the regression equations for predicting compressive strength of in-situ concrete. They have selected

Modeling the permittivity of electrolyte solutions

Solution of a strong electrolyte in a high‐density polar fluid gives rise to a dielectric saturation that decreases the orientation polarizability of the solvent molecules in close proximity to the ions wherefore the relative permittivity in this region is determined solely by the atomic and electronic polarization. This causes a substantial decrease in the static permittivity of the solution. By considering the dielectric saturation, a model for the permittivity of an electrolyte solution have been developed and the parameters, the relative permittivities at dielectric saturation in close proximity to the ions, for 17 ions in water at 298.15 K were determined. By scaling these relative permittivities in proportion to the permittivity of the solvent, the model could be extended to calculate the permittivity of solutions of electrolytes in methanol and admixtures of water and ethanol. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2854–2860, 2015

Influence of water addition on the structure of plasma-deposited allyl alcohol polymer films

One hundred and fifty nanometre thick polymer films made of allyl alcohol and H2O addition were deposited onto aluminium substrates using the radio-frequency (rf) pulsed plasma mode. The structure–property relationships of polymer films were studied in dependence on the precursor ratio allyl alcohol-water. Both the regularity of structure and composition of such thin films in comparison to chemically polymerized allyl alcohol were investigated using by bulk-sensitive Fourier transform infrared spectroscopy (FTIR) in the spectral range of 4000–500 cm−1 as well as surface-sensitive X-ray photoelectron spectroscopy (XPS). The intention of this work was to increase the yield in OH groups by addition of water to the allyl alcohol precursor. For an unambiguous identification of the functionality of the deposited films, the OH groups were labelled with trifluoroacetic anhydride and subsequently measured by XPS as well as quantitatively by FTIR. As expected, the O/C ratio grew with increasing water admixture by oxidation of both the plasma polymerized allyl alcohol layer to preferably aldehyde and/or carboxylic acid groups. In contrary, the concentration of OH groups in the deposited polymer film decreases dramatically with increasing admixture of water to the allyl alcohol plasma. It has been shown that the additional water has produced preferably higher oxidized C-Ox species with two or three C–O bonds. This fits also very well with the observation that almost no deuterium is introduced into the surface of plasma polymer if D2O was added instead of H2O.

Water Effect on Proton Exchange of X-cut Lithium Niobate in the Melt of Benzoic Acid

The influence of controllable amount of water admixture (up to 0.5 w.%) in benzoic acid on the proton exchange process of X-cut congruent lithium niobate was studied in this paper by means of mode spectroscopy, optical microscopy, optical profilometry, atomic force microscopy, XRD, and chemical etching. It has been determined that addition of 0.5 w.% Н2О to benzoic acid increases proton exchange rate and changes phase composition and number of defects of proton exchanged layer in lithium niobate.

Isomerization of light gasoline fractions: The efficiency of different catalysts and technologies

The experience gained from the industrial use of isomerization catalysts (chlorinated, zeolite, and sulfated oxides) at Russian plants is analyzed. Isomerization has been used in Russia since the late 1990s. Early technologies used zeolite catalysts. The subsequent development of isomerization followed two trends that employed chlorinated and sulfated oxide catalysts. In this work, the advantages and disadvantages of chlorinated catalysts are shown by citing specific examples. The main disadvantages are high sensitivity to water admixtures and sulfur compounds in the raw materials, along with side reactions that yield low octane products in C6 recycling. Sulfated oxide systems are free of such problems, as has been proved in the industrial use of SI-2 sulfated catalyst on different types of plants.

수중 구조물 골재 속채움 시 수중 불분리성 혼화제의 적용 효과

수중 구조물의 건설공사 수요 증가에 따라 구조물을 지반에 고정시키고 지지하기 위한 해양 기초 및 수중 그라우트재에 대한 관심이 높아지고 있고, 이에 대한 다양한 연구가 진행되고 있다. 수중에 시공되는 그라우트재는 물의 흐름에 의해 유실 교란되기 쉽고 양생 중에 재료분리 현상 등으로 인해 시공품질을 확보하기 어려워 설계 강도에 큰 영향을 미친다. 본 연구에서는 해상 모노파일 속채움과 같이 골재를 채운 후 그라우트재를 주입하는 프리플레이스트 공법에 대한 수중 불분리성 혼화제의 적용 효과를 파악하기 위해 골재 크기, 그라우트재의 종류, 물 시멘트비 및 혼화재 등 다양한 시험조건을 상정하여 블리딩 및 압축강도 등의 실내시험을 수행하였으며, 이에 따른 특성을 비교 평가하였다. With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.

Palaeogene non-marine molluscs from Oman: implications for the timing of uplift of the Dhofar Plateau and the opening of the Red Sea and Gulf of Aden

Abstract A collection of terrestrial and freshwater snails from the Late Eocene to earliest Early Oligocene Zalumah Formation at Wadi Darbat, near Salalah, Oman is of importance on account of its taxonomic composition, its palaeoecological indications and its biogeographic affinities which are clearly tropical African; these are very different from the extant non-marine snail fauna of Oman which is typical of the Mediterranean belt. In addition, these fossil snails are by far the oldest-known representatives of their respective genera. The Late Eocene Zalumah deposits which yielded the molluscs accumulated just above sea level, as revealed by the admixture of marine, brackish water and freshwater taxa as well as fully terrestrial gastropods. These deposits now vary in altitude from near sea level at Taqah (Wadi Darbat) to over 930 m at Thaytiniti. Uplift of the Dhofar Plateau therefore must have occurred later than the Early Oligocene. The biogeographic affinities of the snails confirms that the Arabian Peninsula was part of the African continent at the time of deposition and that the opening of the Red Sea and the Gulf of Aden occurred later than the Early Oligocene.

The Evaluation of Rapid Cooling As an Anesthetic Method for the Zebrafish

As zebrafish became a popular research system in contemporary biomedical research, effective anesthesia, which had low toxicity and high efficacy, was needed. The objective of this article was to evaluate the anesthetic effect of rapid cooling for embryo and larvae zebrafish with ice slush (ice and water admixture). The time to stage 5 anesthesia and maintaining for more than 5 s were detected and compared to MS-222 anesthesia. Besides, the time of recovery from anesthesia, mortality, and the survivability were measured and compared with MS-222 anesthesia. The results showed that anesthesia was generally achieved within 10 s for rapid cooling, which was more rapid than MS-222. The survivability assay demonstrated that rapid cooling was suitable for embryo and larvae zebrafish (1-14 days) and could be used for repeated anesthesia. The most important advantage was that this anesthesia could persist for 10 min and had no mortality. These findings suggested that rapid cooling provided advantages of improved safety, rapid anesthesia, and potentially low mortality rates and could be an effective anesthetic method for scientific research.