An evaluated compilation of equilibrium relative humidities in air versus temperature from pure phase to approximately 105 pascal (1 atm) in pressure is presented for 28 binary saturated aqueous solutions. The relative humidities of the solutions range from about 3 to 98 percent. Using a data base from 21 separate investigations comprising 1106 individual measurements, fits were made by the method of least squares to regular polynomial equations with two through four coefficients. Equations and tables are presented along with the estimated uncertainties in the correlated results.
{"title":"Humidity Fixed Points of Binary Saturated Aqueous Solutions","authors":"L. Greenspan","doi":"10.6028/jres.081A.011","DOIUrl":"https://doi.org/10.6028/jres.081A.011","url":null,"abstract":"An evaluated compilation of equilibrium relative humidities in air versus temperature from pure phase to approximately 105 pascal (1 atm) in pressure is presented for 28 binary saturated aqueous solutions. The relative humidities of the solutions range from about 3 to 98 percent. Using a data base from 21 separate investigations comprising 1106 individual measurements, fits were made by the method of least squares to regular polynomial equations with two through four coefficients. Equations and tables are presented along with the estimated uncertainties in the correlated results.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1977-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81436992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The standard pH values of the solution of potassium hydrogen phthalate (molality 0.05 mol kg−1) have been redetermined over the temperature range 0 to 60 °C, using SRM 185d. Extensive measurements were made of the emf of cells of the type Pd;H2(g,1atm)|KH phthalate(m=0.05),KCl(m)|AgCl;Agwhere mKCl was 0.015, 0.01, or 0.005 mol kg−1, from which values of the acidity function p(aHγCl) were derived. The pH convention defines γCl the range of ionic strengths 0 to 0.1 mol kg−1 and permits conventional values of paH be obtained. According to NBS procedures, paH for selected reference solutions is identified with the standard pH(S) in the operational definition of pH. The new values, given in terms of the thermodynamic temperature (T) by PH(S)=2073.44T−13.3270+0.045199T−3.4846×10−5T2differ, on the average, by 0.003 unit from the results based on the 1944 data of Hamer and Acree.
{"title":"Standard pH Values for the Potassium Hydrogen Phthalate Reference Buffer Solution from 0 to 60 °C","authors":"H. Hetzer, R. Durst, R. Robinson, R. Bates","doi":"10.6028/jres.081A.005","DOIUrl":"https://doi.org/10.6028/jres.081A.005","url":null,"abstract":"The standard pH values of the solution of potassium hydrogen phthalate (molality 0.05 mol kg−1) have been redetermined over the temperature range 0 to 60 °C, using SRM 185d. Extensive measurements were made of the emf of cells of the type Pd;H2(g,1atm)|KH phthalate(m=0.05),KCl(m)|AgCl;Agwhere mKCl was 0.015, 0.01, or 0.005 mol kg−1, from which values of the acidity function p(aHγCl) were derived. The pH convention defines γCl the range of ionic strengths 0 to 0.1 mol kg−1 and permits conventional values of paH be obtained. According to NBS procedures, paH for selected reference solutions is identified with the standard pH(S) in the operational definition of pH. The new values, given in terms of the thermodynamic temperature (T) by PH(S)=2073.44T−13.3270+0.045199T−3.4846×10−5T2differ, on the average, by 0.003 unit from the results based on the 1944 data of Hamer and Acree.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1977-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87799533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new formulation is presented for the vapor pressure of ice from the triple point to −100 °C based on thermodynamic calculations. Use is made of the definitive experimental value of the vapor pressure of water at its triple point recently obtained by Guildner, Johnson, and Jones. A table is given of the vapor pressure as a function of temperature at 0.1-degree intervals over the range 0 to −100 °C, together with the values of the temperature derivative at 1-degree intervals. The formulation is compared with published experimental measurements and vapor pressure equations. It is estimated that this formulation predicts the vapor pressure of ice with an overall uncertainty that varies from 0.016 percent at the triple point to 0.50 percent at −100 °C.
{"title":"Vapor Pressure Formulation for Ice","authors":"A. Wexler","doi":"10.6028/jres.081A.003","DOIUrl":"https://doi.org/10.6028/jres.081A.003","url":null,"abstract":"A new formulation is presented for the vapor pressure of ice from the triple point to −100 °C based on thermodynamic calculations. Use is made of the definitive experimental value of the vapor pressure of water at its triple point recently obtained by Guildner, Johnson, and Jones. A table is given of the vapor pressure as a function of temperature at 0.1-degree intervals over the range 0 to −100 °C, together with the values of the temperature derivative at 1-degree intervals. The formulation is compared with published experimental measurements and vapor pressure equations. It is estimated that this formulation predicts the vapor pressure of ice with an overall uncertainty that varies from 0.016 percent at the triple point to 0.50 percent at −100 °C.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1977-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81385619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fluorescence efficiency of xanthene dyes, oxazine dyes, and 7-aminocoumarins is discussed. Relations with the molecular structure are pointed out and dependence on solvent and temperature is explained. Several new fluorescence standards are suggested.
{"title":"Fluorescence Efficiency of Laser Dyes*","authors":"K. Drexhage","doi":"10.6028/jres.080A.044","DOIUrl":"https://doi.org/10.6028/jres.080A.044","url":null,"abstract":"The fluorescence efficiency of xanthene dyes, oxazine dyes, and 7-aminocoumarins is discussed. Relations with the molecular structure are pointed out and dependence on solvent and temperature is explained. Several new fluorescence standards are suggested.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1976-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76042887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Long-time creep of natural rubber cured with a sulfur-accelerator recipe containing no filler can be conveniently represented by a plot of (E - E 1)/E 1 = ΔE/E 1 with a double-abscissa scale showing log t and t. E is the elongation at any time t, after application of the load, and E 1 its value at unit time. Experimental data conform to the equation except for a more rapid rise preceding rupture. The constants A and B can be evaluated from only three observations-at the longest time (about 70 days), at one minute, and at an intermediate time. ΔE/E 1 is approximately linear with log t when t is less than 0.1(A/B) and approximately linear with t when t is greater than 4.343(A/B). The observed modulus was about 1.4 MPa and A was about 2.4 percent/(unit log t) when the atmosphere was a vacuum, dry N2, or dry air. The modulus was lowered very slightly and A became about 4 percent/(unit log t) when the air was saturated with water. B was raised from about 2 × 10-5 percent/min to about 20 × 10-5 percent/min when the vacuum or dry N2 was replaced by dry air and to about 50 × 10-5 percent/min when the air was saturated with moisture. A is considered to be related to physical relaxation, while B corresponds to a chemical reaction, probably oxidative degradation.
{"title":"Long-Time Creep in a Pure-Gum Rubber Vulcanizate: Influence of Humidity and Atmospheric Oxygen.","authors":"L. Wood, G. W. Bullman, F. Roth","doi":"10.5254/1.3547441","DOIUrl":"https://doi.org/10.5254/1.3547441","url":null,"abstract":"Long-time creep of natural rubber cured with a sulfur-accelerator recipe containing no filler can be conveniently represented by a plot of (E - E 1)/E 1 = ΔE/E 1 with a double-abscissa scale showing log t and t. E is the elongation at any time t, after application of the load, and E 1 its value at unit time. Experimental data conform to the equation except for a more rapid rise preceding rupture. The constants A and B can be evaluated from only three observations-at the longest time (about 70 days), at one minute, and at an intermediate time. ΔE/E 1 is approximately linear with log t when t is less than 0.1(A/B) and approximately linear with t when t is greater than 4.343(A/B). The observed modulus was about 1.4 MPa and A was about 2.4 percent/(unit log t) when the atmosphere was a vacuum, dry N2, or dry air. The modulus was lowered very slightly and A became about 4 percent/(unit log t) when the air was saturated with water. B was raised from about 2 × 10-5 percent/min to about 20 × 10-5 percent/min when the vacuum or dry N2 was replaced by dry air and to about 50 × 10-5 percent/min when the air was saturated with moisture. A is considered to be related to physical relaxation, while B corresponds to a chemical reaction, probably oxidative degradation.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75240179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reactions of fluorocarbon ions in C2F6. Implications for the radiolysis","authors":"L. W. Sieck, R. Gorden, P. Ausloos","doi":"10.6028/JRES.078A.012","DOIUrl":"https://doi.org/10.6028/JRES.078A.012","url":null,"abstract":"","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1974-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78198247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silica-rich and boron-rich binary glasses resemble c1athrates in having host cavities in which modifier oxides may be inclosed without stress as inactive gues ts until the cavities are approximately fill ed. Additional modification results in stress both in the holes of the matrix and the cavities of vitrons. Then the structur e begins to disintegrate and mixing takes place. The r equired mole-percent modification is expressed by an equation of the form
{"title":"Relation of vitron theory to 2-layer-liquid immiscibility in binary silicate and borate glass melts","authors":"L. W. Tilton","doi":"10.6028/JRES.077A.018","DOIUrl":"https://doi.org/10.6028/JRES.077A.018","url":null,"abstract":"Silica-rich and boron-rich binary glasses resemble c1athrates in having host cavities in which modifier oxides may be inclosed without stress as inactive gues ts until the cavities are approximately fill ed. Additional modification results in stress both in the holes of the matrix and the cavities of vitrons. Then the structur e begins to disintegrate and mixing takes place. The r equired mole-percent modification is expressed by an equation of the form","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1973-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86034498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The yield and mode of formation of acetylene in the radiolysis of CH4 at atmospheric pressures have been a matter of speculation for many years [1-7]t. Ion pair yields of acetylene varying between 0.0 and 0.25 have been reported in various studies in which the dose rates were in the range 10 15 to 1022 eV/g·s. There are indications that M(C 2H2 )/N + increases with an increase in dose rate [5] or decreases in absorbed dose [1]. Actually, consistently high values for M(C 2H 2}/N+ have recently been reported in studies where a field emission source was employed [6-81 which delivered 3 to 60 ns electron pulses with average dose rates which were about five orders of magnitude higher than those in the linear accelerator studies [5]. In contrast with the lower dose rate studies the agreement between the three Febetron 2 studies r6-81 was excellent;
{"title":"Radiolysis of methane. Formation of acetylene","authors":"R. Rebbert, P. Ausloos","doi":"10.6028/jres.077a.005","DOIUrl":"https://doi.org/10.6028/jres.077a.005","url":null,"abstract":"The yield and mode of formation of acetylene in the radiolysis of CH4 at atmospheric pressures have been a matter of speculation for many years [1-7]t. Ion pair yields of acetylene varying between 0.0 and 0.25 have been reported in various studies in which the dose rates were in the range 10 15 to 1022 eV/g·s. There are indications that M(C 2H2 )/N + increases with an increase in dose rate [5] or decreases in absorbed dose [1]. Actually, consistently high values for M(C 2H 2}/N+ have recently been reported in studies where a field emission source was employed [6-81 which delivered 3 to 60 ns electron pulses with average dose rates which were about five orders of magnitude higher than those in the linear accelerator studies [5]. In contrast with the lower dose rate studies the agreement between the three Febetron 2 studies r6-81 was excellent;","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1973-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86584380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1972-11-01DOI: 10.1007/978-3-642-49204-4_23
G. Guilbault
{"title":"Newer Fluorometric Methods for the Analysis of Biologically Important Compounds.","authors":"G. Guilbault","doi":"10.1007/978-3-642-49204-4_23","DOIUrl":"https://doi.org/10.1007/978-3-642-49204-4_23","url":null,"abstract":"","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1972-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81001547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natural rubber mixed with varying amounts of dicumyl peroxide was cross-linked by heating 120 min at 149 °C. The quantitative measure of cross-linking was taken as the amount fp of decomposed dicumyl peroxide, the product of p, the number of parts added per hundred of rubber and f the fraction decomposed during the time of cure. The shear creep modulus G was calculated from measurements of the indentation of a flat rubber sheet by a rigid sphere. The glass transition temperature T g , was raised about 1.2 °C for each part of decomposed dicumyl peroxide. Above (T g + 12) the modulus-temperature relations were linear with a slope that increased with increasing cross-linking. The creep rate was negligible except near the glass transition and at low values of fp. Values of G, read from these plots at seven temperatures, were plotted as a function of fp. The linearity of the two plots permits the derivation of the general relation: G = S(fp + B)T + H(fp + B) + A where A, B, H, and S are constants. The lines representing G as a function of fp at each temperature all intersected near the point, fp = 0.45 phr, G = 2.70 Mdyn cm-2 (0.270 MN m-2). The constants were evaluated as A = 2.70 Mdyn cm-2, B = -0.45 phr, S = 5.925 × 10-3 Mdyn cm-2(phr)-1K-1 and H = 0.0684 (Mdyn cm-2) (phr)-1. This equation represented satisfactorily all the data obtained at temperatures from -50 to +100 °C for values of fp from about 1 to 24 phr.
将天然橡胶与不同量的过氧化二氨基混合，在149℃下加热120 min交联。交联的定量指标为过氧化二氨基的分解量fp、产物p、每百橡胶加入的份数和固化过程中分解的分数f。用刚性球测量橡胶板的压痕，计算了剪切蠕变模量G。过氧化二氨基每部分的玻璃化转变温度提高1.2℃左右。在(T g + 12)以上，模量与温度呈线性关系，斜率随交联的增加而增大。除了在玻璃化转变附近和fp值较低时，蠕变速率可以忽略不计。在7种温度下从这些图中读取的G值被绘制为fp的函数。两个图的线性关系允许推导一般关系:G = S(fp + B)T + H(fp + B) + A，其中A, B, H和S是常数。在每个温度下，代表G作为fp函数的线都在点附近相交，fp = 0.45 phr, G = 2.70 Mdyn cm-2 (0.270 MN m-2)。测定常数为A = 2.70 Mdyn cm-2, B = -0.45 phr, S = 5.925 × 10-3 Mdyn cm-2(phr)-1K-1, H = 0.0684 (Mdyn cm-2) (phr)-1。该方程令人满意地表示了在-50至+100°C温度下fp值约为1至24 phr时获得的所有数据。
{"title":"Modulus of Natural Rubber Cross-Linked by Dicumyl Peroxide. I. Experimental Observations.","authors":"L. Wood, G. W. Bullman, G. Decker","doi":"10.5254/1.3544746","DOIUrl":"https://doi.org/10.5254/1.3544746","url":null,"abstract":"Natural rubber mixed with varying amounts of dicumyl peroxide was cross-linked by heating 120 min at 149 °C. The quantitative measure of cross-linking was taken as the amount fp of decomposed dicumyl peroxide, the product of p, the number of parts added per hundred of rubber and f the fraction decomposed during the time of cure. The shear creep modulus G was calculated from measurements of the indentation of a flat rubber sheet by a rigid sphere. The glass transition temperature T g , was raised about 1.2 °C for each part of decomposed dicumyl peroxide. Above (T g + 12) the modulus-temperature relations were linear with a slope that increased with increasing cross-linking. The creep rate was negligible except near the glass transition and at low values of fp. Values of G, read from these plots at seven temperatures, were plotted as a function of fp. The linearity of the two plots permits the derivation of the general relation: G = S(fp + B)T + H(fp + B) + A where A, B, H, and S are constants. The lines representing G as a function of fp at each temperature all intersected near the point, fp = 0.45 phr, G = 2.70 Mdyn cm-2 (0.270 MN m-2). The constants were evaluated as A = 2.70 Mdyn cm-2, B = -0.45 phr, S = 5.925 × 10-3 Mdyn cm-2(phr)-1K-1 and H = 0.0684 (Mdyn cm-2) (phr)-1. This equation represented satisfactorily all the data obtained at temperatures from -50 to +100 °C for values of fp from about 1 to 24 phr.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1972-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85112075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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