Excess Volumes Research Articles

A new activity model for Fe\u2013Mg\u2013Al biotites: I\u2014Derivation and calibration of mixing parameters

A new activity model for Fe–Mg–Al biotites is formulated, which extends that of Mg–Al biotites (Dachs and Benisek, Contrib Mineral Petrol 174:76, 2019) to the K2O–FeO–MgO–Al2O3–SiO2–H2O (KFMASH) system. It has the two composition variables XMg = Mg/(Mg + Fe2+) and octahedral Al, and Fe–Mg and Mg–Al ordering variables resulting in five linearly independent endmembers: annite (Ann, K[Fe]M1[Fe]2M2[Al0.5Si0.5]2T1[Si]2T2O10(OH)2, phlogopite (Phl, K[Mg]M1[Mg]2M2[Al0.5Si0.5]2T1[Si]2T2O10(OH)2, ordered Fe–Mg biotite (Obi, K[Fe]M1[Mg]2M2[Al0.5Si0.5]2T1[Si]2T2O10(OH)2, ordered eastonite (Eas, K[Al]M1[Mg]2M2[Al]2T1[Si]2T2O10(OH)2, and disordered eastonite (Easd, K[Al1/3Mg2/3]M1[Al1/3Mg2/3]2M2[Al]2T1[Si]2T2O10(OH)2. The methods applied to parameterize the mixing properties of the model were: calorimetry, analysis of existing phase-equilibrium data, line-broadening in powder absorption infrared (IR) spectra, and density functional theory (DFT) calculations. For the calorimetric study, various biotite compositions along the annite–phlogopite, annite–siderophyllite (Sid, K[Al]M1[Fe]2M2[Al]2T1[Si]2T2O10(OH)2), and annite–eastonite joins were synthesized hydrothermally at 700 °C, 4 kbar and logfO2 of around − 20.2, close to the redox conditions of the wüstite–magnetite oxygen buffer at that P–T conditions. The samples were characterised by X-ray powder diffraction (XRPD), energy-dispersive scanning electron microprobe analysis, powder absorption IR spectroscopy, and optical microscopy. The samples were studied further using relaxation calorimetry to measure their heat capacities (Cp) at temperatures from 2 to 300 K. The measured Cp/T was then integrated to get the calorimetric (vibrational) entropies of the samples at 298.15 K. These show linear behaviour when plotted as a function of composition for all three binaries. Excess entropies of mixing are thus zero for the important biotite joins. Excess volumes of mixing are also zero within error for the three binaries Phl-Ann, Ann-Sid, and Ann-Eas. KFMASH biotite, therefore, has excess enthalpies which are independent of pressure and temperature (WGij = WHij). A least-squares procedure was applied in the thermodynamic analysis of published experimental data on the Fe–Mg exchange between biotite and olivine, combined with phase-equilibrium data for phlogopite + quartz stability and experimental data for the Al-saturation level of biotite in the assemblage biotite–sillimanite–sanidine–quartz–H2O to constrain enthalpic mixing parameters and to derive enthalpy of formation values for biotite endmembers. For Fe–Mg mixing in biotite, the most important binary, this gave best-fit asymmetric Margules enthalpy parameters of WHAnnPhl = 14.3 ± 3.4 kJ/mol and WHPhlAnn = −8.8 ± 8.0 kJ/mol (3-cation basis). The resulting asymmetric molar excess Gibbs free energy (Gex) departs only slightly from ideality and is negative at Fe-rich and positive at Mg-rich compositions. Near-ideal activity–composition relationships are thus indicated for the Ann–Phl binary. The presently used low value of − 2 kJ/mol for the enthalpy change of the reaction 2/3 Phl + 1/3 Ann = Obi is generally confirmed by DFT calculations that gave − 2 ± 3 kJ/mol for this ∆HFe–Mg order, indicating that Fe–Mg ordering in biotite is weak. The large enthalpy change of ∆HMg-Al disorder = 34.5 kJ/mol for the disordering of Mg and Al on the M sites in Eas (Dachs and Benisek 2019) is reconfirmed by additional DFT calculations. In combination with WHPhlEas = 10 kJ/mol, which is the preferred value of this study describing mixing along the Phl–Eas join, Mg–Al disordering over the M sites of biotite is predicted to be only significant at high temperatures > 1000 °C. In contrast, it plays no role in metamorphic P–T settings.

MOLECULAR INTERACTION STUDIES OF PHENOL WITH ACETALDEHYDE USING ULTRASONIC AND FTIR TECHNIQUE

The densities ( ), viscosities ( ) and ultrasonic velocities (U) were measured for the binary mixtures of Phenol with Acetaldehyde at 303K.Excess volumes (VmE), isentropic compressibilities (ksE) and isentropic compressibilities (ksE) were determined from these experimental findings. To obtain their coefficients and standard deviations, the excess or deviation properties were based on Redlich-Kister polynomial equation. Depending on the molecular interactions between the components of hetero molecules, the excess or deviation properties were considered either negative, and the nature of liquid mixtures was studied in terms of molecular interactions by steric and electronic effects. The FTIR provides support to thermodynamic studies to classify different interactions between molecules that are unlike them.

Estimation of Thermodynamic Properties and Phase Equilibria in Systems of Deep Eutectic Solvents by PC-SAFT EoS

This study examines the capabilities and shortcomings of perturbed-chain-statistical associating fluid theory equations of state (PC-SAFT EoS) applied for predicting properties and phase equilibria in systems of deep eutectic solvents. Treating deep eutectic solvents as pseudo-pure compounds and describing them as mixtures of two independent constituents are explored. Examples of choline chloride as the hydrogen bond acceptor (HBA) and levulinic acid, ethylene glycol, and phenol as hydrogen bond donors (HBDs) in a 1:2 molar ratio are considered. Excess properties of deep eutectic solvents with n-alkanols and water along with solubilities of carbon dioxide and ammonia are also considered. Besides that, liquid–liquid ternary systems of deep eutectic solvents with n-alkanes and 1-alkanols are analyzed. It has been found that although the pseudo-pure compounds approach with 2B associative scheme correctly estimates excess volumes, it exhibits poor accuracy in predicting excess enthalpies, solubility data, and liquid–liquid equilibria in ternary systems. When a temperature-dependent binary interaction between HBA and HBDs is applied, the individual approach predicts these properties in a more accurate manner.

Spectrum of embrittling potencies and relation to properties of symmetric-tilt grain boundaries

Grain boundaries in metallic materials can exist in a wide range of stable and metastable structures. In addition, the properties of a grain boundary may be altered through solute segregation. In this work, we present a formulation that combines the spectrum of embrittling potencies associated with solute segregation with site-occupancy statistics. As a prototype problem, we illustrate the relation between segregation and embrittlement in the case of S segregation to grain boundaries in Ni. To obtain a population of site segregation energies, we perform molecular statics calculations on 378 different symmetric-tilt grain boundaries and their free surface equivalents, using an embedded-atom method interatomic potential developed specifically for studying embrittlement. Our results show that it is important to consider both the energies associated with embrittlement and the probability of occupancy to describe the general embrittling nature of a grain boundary. When analyzed in isolation, certain grain boundaries show large embrittling potencies; however, that effect is diminished when the probability of S segregation to that grain boundary is considered within a polycrystal. We propose a new quantity, the embrittling estimator, which not only categorizes grain boundaries as embrittling or strengthening, but also considers site occupancy probabilities, so that the embrittlement behavior of grain boundaries within a network of grain boundaries can be compared. Finally, we examine the relationship between embrittlement behavior and innate grain boundary properties, such as the free volume, and find statistical evidence that the complex nature of embrittlement cannot be explained by linear correlations with excess volumes or energies. Ultimately, this combined approach provides a theoretical tool to assist grain boundary engineering of metastable alloys.

Densities and Viscosities of Ionic Liquid with Organic Solvents

The ionic liquid (IL) of 1-hexyl-3-methylimidazolium acetate is widely used in chemical and bio-chemical processes. In this work, due to the high viscosity of IL, the promising chemicals (i.e., N, N-dimethylacetamide, N, N-dimethylformamide, and dimethyl sulfoxide) were selected as the additives to lower IL viscosity. The thermophysical properties of density and viscosity for IL with solvents were measured using a digital vibrating U-tube densimeter and an Ubbelohde capillary viscometer from 303.15 to 338.15 K at atmospheric pressure (0.0967 MPa), respectively. The influences of the solvents on the thermophysical properties of ionic liquid were quantitatively studied. Furthermore, based on the measurement values, the derived properties of excess molar volumes, thermal expansion coefficient, and the energy barrier were calculated, and the results showed that the mixture composition had great impact on excess volume change and viscosity. The hard-sphere model was employed to reproduce the viscosity. The infrared spectroscopy was performed to study the chemical structure to further understand the interactions between IL and the solvents.

Study on the thermophysical properties of waste cooking oil biodiesel fuel blends with 1-butanol

An Anton Paar vibrating tube densimeter HPM DMA calibrated with an uncertainty of ±0.7 kg•m−3 has been used for accurate measurements of liquid densities of Waste Cooking Oil Biodiesel (WCOB) and 1-butanol as pure fluids and binary liquid mixtures. The densities measurements were performed at temperatures (298.15 K to 393.15 K) and pressures (0.1 MPa to 140 MPa) and showing an absolute deviation of less than 0.007 g/cm−3 compared to the literature data. Using these new experimental data (908 points), excess molar volumes VE, isobaric thermal expansivity, αp, and isothermal compressibility, кT, have been calculated. The Tait and PC-SAFT equations correlate successfully the densities with a small absolute average deviation (AAD), the PC-SAFT model performs very well in all concentration range with a global absolute average deviation (AAD) of 0.325% and for Tait equation a global absolute average deviation of 0.086% for each concentration. PC-SAFT equation correlates satisfactorily the density and shows that it can explain the same interactions between fluid molecules contrary to the Tait equation. Excess volumes values were calculated from the experimental data and show a positive parabolic shape in all composition range almost symmetrical in the fraction molar 0.5. Furthermore, VE values were fitted to the Redlich-Kister equation and showed satisfactory correlation with very small standard deviation values with a global of 4.23·10−5 cm3·mol−1.

РЫНОЧНЫЙ ПОТЕНЦИАЛ ИННОВАЦИОННЫХ ПРОДУКТОВ ЛЕСНОЙ ПРОМЫШЛЕННОСТИ

The article summarizes the data on the competitive advantages of innovative forest products in Russia and abroad. It is noted that the Russian market is not completely ready for innovative products that have been intensively developed recently. To ensure universal promotion of new products, it is necessary to use a system of product standardization, improve staff skills, and increase consumer literacy. The problem is that many innovative products are developed abroad and enter the Russian market as a result of foreign investment in the Russian timber industry. The production of composite structural wood materials is due to the fact that in some regions of the world there is a large proportion of low-quality wood raw materials, which cannot be used in industry in the form of balances, technological raw materials and firewood. Innovative technologies make it possible to obtain construction and structural materials from low-quality wood raw materials, in which there are no shortcomings of solid wood. New structural wood materials fill specific market niches, leading to deeper market differentiation. The price factor largely determines the demand for innovative products in the domestic market, otherwise, excess volumes of products are exported to foreign markets.

Comments on “Interpretation of hydrogen bonding formation through thermodynamic, spectroscopic and DFT studies between isoamyl alcohol and benzyl alcohol at T = (293.15 to 318.15) K”

A polemic is given regarding the volumetric properties reported in the published by Satheesh and coworkers. The authors' calculated partial molar volumes and partial molar excess volumes of the individual mixture components are both found to be thermodynamically inconsistent with the respective excess molar volumes of the binary mixtures containing isoamyl alcohol and benzyl alcohol.

The lattice parameter – composition relationship of the body centered cubic uranium-niobium alloys

In-situ time-of-flight neutron diffraction experiments were performed on uranium-niobium alloy with 6 wt% Nb to study the lattice parameter-composition relationship for the body centered cubic (bcc) alloys. Based on lattice-parameter measurements of Nb-supersaturated γs phase over the range of 450 – 790 °C, an improved Vegard's-type relationship was established for determination of Nb concentrations at elevated temperatures. Neutron diffraction data were also collected as a function of aging time over the 450 - 600 °C range when γs phase decomposed isothermally into the mixture of orthorhombic α-U and Nb-rich bcc phase, as well as at room-temperature on the alloys aged ex-situ at 500 °C up to five years. From these measurements, the average Nb concentrations in the bcc phase were determined based on the Rietveld refinements of weight fraction and mass conservation relations (lever rule). Over the 15at% – 78at% range of Nb concentrations that correspond to different experimental aging times, the lattice parameters at constant temperatures exhibit a nonlinear S-shaped variation with Nb concentration, and the associated excess volumes of mixing can be described by a subregular solution model of the Redlich–Kister type of polynomial. Over the full range of composition the S-shaped deviation from Vegard's law can be modeled using a combination of an elastic continuum model and a perturbation to the radii of the solute atoms in the solvent, suggesting that electronic interactions between solute and solvent atoms could play an important role in the compositional dependence of lattice parameter for the γ-phase U-Nb alloys. While Vegard's law is a straightforward and reasonably good approximation for the bcc solid solutions in the U-Nb system, the Nb concentrations determined from the weight fraction refinements of diffraction data provide internally consistent, mass-conserving estimates of solute redistribution for the monotectoid reaction.

Meme Koruyucu Cerrahi Sonrası (MKC) Simultane İntegre Boost (SIB) Tekniğinin Farklılığı

Whole breast irradiation after breast conserving surgery (BCS) is the standard treatment for early stage breast cancer. For early-stage breast cancer, breast-conserving surgery and subsequent postoperative radiotherapy are as effective as mastectomy. An early stage 10 breast cancer patient admitted to the Radiation Oncology Clinic of Sisli Hamidiye Etfal Training and Research Hospital was included in the study. The study is a retrospective study and patients were not treated with the plans and techniques used in the studies. In the study, the planning target volume (PTV) and the organs at risk (OAR) planned with Sequential Intensity Modulated Radiotherapy (IMRT) and Simultaneous Integrated Supplement (Boost) Intensity Modulated Radiotherapy (SIB IMRT) techniques in patients who have undergone breast conserving surgery due to breast cancer. It is aimed to be compared dosimetrically. For the study, patients with consecutive IMRT were given 50 Gy / 25 fraction to the whole breast and 10 Gy / 5 fraction to the boost area, while patients with SIB IMRT were given a total of 50.4 Gy / 28 fractions to the entire breast, while additional dose to the boost volume was given 60 Gy / 28 fraction dose. Ipsilateral lung, heart, the minimum and maximum doses of the PTV breast and PTV boost areas and the homogeneity index (HI), conformity index (CI) values were matched with the help of the t - test minitab program. SIB IMRT technique and Sequential IMRT technique the ipsilateral lung; When the average doses of V5 value for 10 patients are compared, the results are not statistically significant, while the V20 value is statistically significant when the average dose values for 10 patients are compared, it has been demonstrated that SIB IMRT technique can be performed with a lower dose in the ipsilateral lung V20. When the heart average and heart V20 values are compared for the two techniques, the SIB IMRT technique was not statistically significant, and it has no superiority over the Sequential IMRT technique. While dose homogeneity was better with SIB IMRT in whole breasts, there was no difference in boost area homogeneity and whole breast conformity index SIB IMRT technique for decreasing excess normal tissue volumes irradiated, shortening the treatment process, dose reduction in organs at risk, reducing the dose per fraction for the breast and increasing the dose per fraction to the boost area due to the low incidence of acute skin toxicity, standard use in breast protector RT it can be recommended for.

Insights into non-ideal behaviour of benzyl alcohol with (C2-C4) carboxylic acids through volumetric, ultrasonic and ATR-FTIR spectroscopic studies

ABSTRACT In the present work, experimental density (ρ) and speed of sound (u) data for the binary mixtures of benzyl alcohol with acetic acid, propionic acid, and n-butyric acid have been reported over the complete range of mole fraction at 298.15 K ≤ T ≤ 313.15 K. Excess volumes (VE ), excess isentropic compressibilities (κs E ), excess partial molar volumes (), and excess partial molar volumes at infinite dilution () have been computed from the experimental data. The excess thermodynamic properties are found to be negative over the entire range of composition at the investigated temperatures. The temperature dependence of the excess thermodynamic properties has been investigated. All the excess functions are correlated with the Redlich-Kister equation. Further, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra for the studied binary solutions have been recorded at the equimolar composition to evaluate the extent of cross-association between component molecules through intermolecular hydrogen bonding.

Towards Aqueous – Fluorous – Hydrogenous emulsions: Phase equilibria and liquid structure of (water + 1H,1H-Perfluorobutanol + 1-butanol) ternary mixture

The liquid-liquid equilibrium for the ternary mixture (1-Butanol + 1H,1H-Perfluorobutanol + Water) was determined at 298.6 K. The system displays a type 2 diagram (band-like) characterized by an immiscibility band resulting from the overlap of two regions of partial miscibility.The solubility of water in the binary mixtures of the two alcohols is very high, always above 0.34 mole fraction. The organic phase is thus a complex mixture of aqueous, fluorous and hydrogenous domains.Liquid densities were measured as a function of composition for (water + BuOH) and (water + HFB) binary mixtures and for the ternary mixtures along the organic saturation line. The excess volumes of the binary and ternary mixtures were calculated. The system displays remarkable volumetric effects: water dissolves in BuOH with volume contraction, in HFB with volume expansion and the excess volume of the ternary saturated organic mixtures is positive throughout most of the composition range.Atomistic molecular dynamics simulations were performed enabling a molecular level perception of the organization and interactions of the ternary system. The results accurately reproduce the experimental excess volumes data of the binary and ternary mixtures, fully validating the simulations. The simulation results reveal the existence of clusters of water molecules, coexisting with hydrogenated and fluorinated domains at concentrations near saturation.

Do Mutual Funds Flows Lead to Fire-sales and Pose Systemic Risk?

Assessing systemic risk of mutual funds as a result of liquidity transformation is difficult because the frequency of flow and holdings data available is too low to properly isolate the price impact of redemption-driven sales of portfolio assets. Exchange-traded funds (ETFs) offer the advantage of daily observations of redemptions as well as the exact assets which might be sold in the underlying market. Exploiting this advantage, we show for extreme redemptions from individual corporate bond ETFs during normal times and stressed markets as well as for the largest aggregate redemptions from all corporate bond ETFs that the concern of systemic risk is not supported by the data. For the most extreme daily redemptions between 2009 and 2017, we find that for many bonds received in-kind for ETF shares, customer sell volumes in excess of average past daily customer sell volumes are either negative or large multiples of the maximum potential redemption implied sale of bonds. Further, we show that among the bonds with positive excess customer sell volumes, the extreme redemption implied sale of bonds relative to the standard deviations of past daily customer sell volumes was large for only very few of them. Corroborating the results, using regression analyses we find no evidence that extreme redemption implied sales of bonds led to abnormal negative price impacts in the underlying bond market. These findings imply that extreme redemption implied asset sales in the corporate bond market have not triggered wide-spread fire sales.

Apparent molal volumes and hydration numbers from viscosity studies for microemulsions with a nonionic surfactant derived from castor oil and a series of polar oils

The cloud point of a nonionic surfactant is related to the hydration of its polar shell. Viscosity data can be used to determine the total amount of water associated with micelles. The aim of this study was to apply this model to a more complex system comprising a series of oil-in-water microemulsions. These consisted of the nonionic surfactant, Kolliphor® RH 40, with and without polar oils. The oils used were isopropyl myristate (IPM), neopentyl glycol diethylhexanoate (NGDO), diisopropyl sebacate (DIS) and diisopropyl adipate (DIA) while the alcoholic solvents ethanol, 2-propanol and diethylene glycol monoethyl ether (DEG) were the co-surfactants. The apparent molal volumes were determined from the densities using a pycnometric method while the viscosities were measured using capillary viscometry. The partial excess volumes with IPM ranked as DEG>2-propanol>ethanol while the excess volumes varied as IPM>NGDO>DIS>DIA. These results were most likely related to the effect of the co-surfactant on the size and curvature of the micellar pseudophase and to the site of oil solubilization, respectively. The presence of oil induced increases in the intrinsic viscosities, the Huggins constants and the hydration numbers. The magnitudes of the latter two parameters were in excellent agreement with the values reported for micelles of nonionic surfactants. With DIS, the changes in the hydration numbers showed a good relationship with the excess volumes. Therefore, meaningful hydration values for microemulsions may be obtained with polar oils which are solubilized in the palisade layer rather than in the core as occurs with hydrophobic oils.

Elucidation of molecular interactions in the mixtures of 2-methoxyaniline with alkyl acetates through transport and thermodynamic properties at T = (303.15, 308.15 and 313.15) K

Abstract Densities, viscosities and speeds of sound of binary mixtures of 2‑methoxy aniline with aliphatic alkyl acetate (methyl acetate, ethyl acetate and butyl acetate) including those of pure liquids, over the entire composition range were measured at various temperatures and atmospheric pressure 0.1 MPa. Using these data, the excess volume, and deviation in viscosity, excess isentropic compressibility, excess partial molar volumes and excess partial molar isentropic compressibilities of the components at infinite dilution were calculated. The excess volume results have been analyzed in the light Prigogine-Flory-Patterson theory. The free volume effect and P* contribution are negative for all the mixtures.

Selection and characterization of non-ideal ionic liquids mixtures to be used in CO2 capture

Due to the costs involved, the capture of CO2 in post-combustion is not currently seen as economically viable. Aiming at changing the perception of post-combustion CO2 from a costly and non-profitable process to a valuable commodity and fostering the development of the next-generation of technologies, novel solvents and their mixtures have been investigated. In this work, mixtures of non-volatile ionic liquids were screened by COSMO-RS aiming to find mixtures with positive excess volumes that could present an increased CO2 capture by physical sorption. The most promising mixtures identified by COSMO-RS, [C4C1im][DMP] or [C4C1im][NTf2] + carboxylate-based protic ILs were characterized through the measurement of their thermophysical properties, namely density and viscosity. Both properties were measured for pure ILs and their binary mixtures at different temperatures and compositions. The temperature dependence of density of pure ILs was described using the Gardas and Coutinho model while viscosity was accurately described using the Vogel−Tammann−Fulcher equation. The Redlich-Kister equation was used to predict the excess molar volumes and the non-ideality of the mixtures’ viscosity was assessed using the Grunberg and Nissan mixing law. The excess molar volumes for mixtures containing [C4C1im][DMP] show large positive values all over the range of compositions and temperatures, making them good candidates for CO2 capture. To the best of our knowledge, the excess molar volumes obtained in this work were the highest reported so far. COSMO-RS was able to correctly predict the trend of the experimental excess molar volumes for these mixtures. Regarding viscosity, mixtures of [C4C1im][DMP] with the carboxylate-based protic ILs led to the desired viscosity decrease compared to the pure aprotic IL, and large deviations from ideality were observed. The mixing of ILs is thus an efficient way to fine-tune the properties, in this case decreasing the viscosity while increasing the sorption capacity.

Back to the basics: Diluted bleach for COVID-19

To the Editor: Since December 2019, COVID-19. a highly pathogenic novel human coronavirus severe acute respiratory syndrome coronavirus (SARS-Cov-2), has emerged from China harboring high human-to-human transmission rates and persistence on inanimate surfaces.1Kampf G. Todt D. Pfaender S. Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.J Hosp Infect. 2020; 104: 246-251Abstract Full Text Full Text PDF PubMed Scopus (2121) Google Scholar An analysis of 22 studies revealed that human coronaviruses similar to COVID-19, including SARS coronavirus, Middle East respiratory syndrome (MERS) coronavirus, and endemic human coronaviruses (HCoV), can persist on inanimate surfaces, such as metal, glass, or plastic, for up to 9 days, but are efficiently inactivated by 62% to 71% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite within 1 minute.1Kampf G. Todt D. Pfaender S. Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.J Hosp Infect. 2020; 104: 246-251Abstract Full Text Full Text PDF PubMed Scopus (2121) Google Scholar A study by van Doremalen et al2van Doremalen N. Bushmaker T. Morris D.H. et al.Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1.N Engl J Med. 2020; Crossref Scopus (5624) Google Scholar evaluating the stability of COVID-19 and SARS-CoV-1 suggests that COVID-19 may remain viable for hours to days on surfaces made from a variety of materials. To help identify commercial disinfectants against COVID-19, the United States Environmental Protection Agency (EPA) has created a list of adequate products by their EPA registration number.3United States Environmental Protection AgencyPesticide Registration. List N: disinfectants for Use Against SARS-CoV-2.https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2Date: 2020Date accessed: March 20, 2020Google Scholar Unfortunately, with exponentially rising COVID-19 cases in the United States, commercial disinfect supplies are in high demand and will unquestionably be limited in the near future. We will have to get creative with available resources, all the while taking safe precautions to ensure our efforts improve and not worsen the ongoing situation. Various dilutions of sodium hypochlorite, effectively Dakin's solution, have been tried and true in dermatology and wound care for many years. To achieve the formulation noted by Kampf et al,1Kampf G. Todt D. Pfaender S. Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.J Hosp Infect. 2020; 104: 246-251Abstract Full Text Full Text PDF PubMed Scopus (2121) Google Scholar ∼0.1% sodium hypochlorite can be made by a roughly 1:50 dilution of household bleach (∼5.25% to 6% sodium hypochlorite) in tap water. Although the Kampf et al analysis is a combination of non–COVID-19 studies, we expect the proposed formulation to similarly also disinfect surfaces of the novel coronavirus. The Centers for Disease Control and Prevention (CDC) also recommends an approximately 1:50 dilution to disinfect COVID-19, explicitly noting 5 tablespoons (one-third cup) bleach per gallon of water or 4 teaspoons bleach per quart of water.4Centers for Disease Control and PreventionClean & Disinfect-Coronavirus Disease 2019: interim Recommendations for U.S. Households with Suspected or Confirmed Coronavirus Disease 2019 (COVID-19).https://www.cdc.gov/coronavirus/2019-ncov/prepare/cleaning-disinfection.htmlDate accessed: March 20, 2020Google Scholar Different dilutions of sodium hypochlorite can vary in their in vivo fibroblast and keratinocyte cytotoxicity; however, dilutions of ∼0.1% sodium hypochlorite are clinically effective with minimal irritation or sensitization.5Ronco C. Mishkin G.J. Disinfection by Sodium Hypochlorite: Dialysis Applications. Karger, Basel, Switzerland2007Google Scholar One should be mindful that corrosive injury on mucous membrane/skin contact is possible with excess volumes or mishandling, so appropriate caution and moderation is necessary.6Slaughter R.J. Watts M. Vale J.A. Grieve J.R. Schep L.J. The clinical toxicology of sodium hypochlorite.Clin Toxicol (Phila). 2019; 57: 303-311Crossref PubMed Scopus (66) Google Scholar This solution should ideally be used within 1 month of preparation and stored in a closed, opaque container at room temperature.7National Research Council (US) and Institute of Medicine (US)Panel on Needle Exchange and Bleach Distribution Programs.in: Normand J. Vlahov D. Moses L.E. Preventing HIV Transmission: The Role of Sterile Needles and Bleach. National Academies Press (US), Washington, DC1995Google Scholar While the exact viral load on inanimate surfaces is unknown during an outbreak, it is critical to disinfect frequently touched surfaces.1Kampf G. Todt D. Pfaender S. Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.J Hosp Infect. 2020; 104: 246-251Abstract Full Text Full Text PDF PubMed Scopus (2121) Google Scholar With rapidly diminishing availability of commercial cleaning supplies, simple diluted bleach, which is readily available, can effectively disinfect our clinics, homes, and environment to prevent sustained transmission from inanimate objects. As with many disinfectants, minimizing long-term skin contact and ensuring good ventilation can minimize clinical toxicity. In Henry Dakin's spirit, we should strive to share with our colleagues the cost-effective, accessible, and relatively safe power of diluted bleach.

Modelling the thermodynamic properties and fluid-phase equilibria of n-perfluoroalkanes and their binary mixtures with the SAFT-γ Mie group contribution equation of state

The SAFT-γ Mie group-contribution approach is extended to describe the thermodynamic properties and fluid-phase behaviour of n-perfluoroalkanes and their binary mixtures. New molecular interaction parameters characterising the functional chemical groups forming these molecules (CF4, CF3 and CF2) are estimated from experimental vapour pressure and saturated-density data of the pure compounds. The vapour–liquid equilibria of four mixtures are then described predictively and compared to recent experimental data from the literature. Additionally, new experimental data for the excess volume of the (n-C6F14 + n-C8F18) mixture is measured over the whole range of compositions, between 278.15 and 318.15 K. The mixture presents small negative excess volumes, which increase in absolute value with increasing temperature. The results are compared with the excess volume for the corresponding mixture of n-alkanes of the same chain length, and with the SAFT-γ Mie predictions. The theory provides a very good description of the properties of both the pure compounds and their binary mixtures.

Excess molar heat capacity for the binary system n-propyl alcohol + water in the temperature range 278.15–358.15 K: new data and application for excess enthalpy calculation

In this work, the new set of the data on the excess heat capacity (CPE ), density (ρ) and excess volumes (VE) for binary system n-propanol + water in the temperature range 278.15–358.15 K are presented. The concentration dependence of CPE was correlated using Redlich–Kister equation. Obtained experimental data of CPE were used to calculate excess enthalpies at various temperatures.

Snow-avalanche boulder fans in Jotunheimen, southern Norway: Schmidt-hammer exposure-age dating, geomorphometrics, dynamics and evolution

ABSTRACTEleven snow-avalanche boulder fans were dated from two high-alpine sites in Jotunheimen using Schmidt-hammer exposure-age dating (SHD) and lichenometry. Average exposure ages of the surface boulders ranged from 2285 ± 725 to 7445 ± 1020 years and demonstrate the potential of SHD for dating active landforms and diachronous surfaces. Application of GIS-based morphometric analyses showed that the volume of rock material within 10 of the fans is accounted for by 16–68% of the combined volume of their respective bedrock chutes and transport zones. It is inferred that the fans were deposited entirely within the Holocene, mainly within the early- to mid Holocene, by frequent avalanches carrying very small debris loads. Relatively small transport-zone volumes are consistent with avalanches of low erosivity. Excess chute volumes appear to represent subaerial erosion in the Younger Dryas and possibly earlier. Debris supply to the fans was likely enhanced by early-Holocene paraglacial processes following deglaciation, and by later permafrost degradation associated with the mid-Holocene Thermal Maximum. The latter, together with the youngest SHD age from one of the fans, may presage a similar increase in geomorphic activity in response to current warming trends.