Simple Static Method Research Articles

Seismic inspection and countermeasures for existing embankments in Japan

Many embankments have been constructed in Japan, but most have lacked seismic design, except for important embankments, such as earth dams. However, because embankments are often damaged by large earthquakes, seismic inspections have recently been carried out on existing embankments, and countermeasures have been taken to deal with unstable embankments. This paper describes the seismic inspection methods and countermeasures currently implemented in Japan for river dikes, tailings dams, and embanked residential lands. River dikes are dangerous when they subside and their crests become lower than the river water levels. Therefore, seismic inspections are being carried out using a simple static method to analyze the amount of subsidence against level 2 seismic motion. Countermeasures are being taken, such as compacting the ground under the vicinity of the toe of a dike. For tailings dams, dynamic analysis is performed for level 2 seismic motion, and seismic inspection is performed based on the amount of slip displacement. As countermeasures, solidification etc. have been implemented. There are 51,306 large residential areas embanked in hilly valleys in Japan. Soil investigations and stability analyses will be conducted in these areas as secondary screenings, and these areas are currently being prioritized for such screenings. It will likely be many years before the screenings and countermeasures are completed.

Experimental measurement and correlation of solubility of ethosuximide in supercritical carbon dioxide

Ethosuximide is a succinimide anticonvulsant active pharmaceutical ingredient. A simple static method by determining the cloud point pressure is employed to measure the solubility of ethosuximide in supercritical carbon dioxide (SC-CO2) at various temperatures T/K = (313.15, 318.15, 323.15 and 328.15) and in pressures P/MPa = (9–15). The experimental solubility of ethosuximide in SC-CO2 is found to be between 3.45E-03 and 8.71E-03 in terms of mole fraction under the experimental conditions. The measured solubility data are successfully correlated by four semi-empirical models including Chrastil, Bartle et al., Kumar and Johnston (K-J) and Mendez-Santiago-Teja (MST). The correlation results show good agreement with the experimental data. The average absolute relative deviation (AARD) between the measured values and the calculated ones are 2.64%, 2.98%, 3.02% and 3.25% for Chrastil, Bartle, K-J and MST respectively. The results of this study provide the effective fundamental for the probable processes based on SC-CO2.

Solubility of capecitabine and docetaxel in supercritical carbon dioxide: Data and the best correlation

The solubility values of some chemotherapeutic agents such as capecitabine (CPT), docetaxel (DTX), and 5-fluorouracil (5-FU) were evaluated in supercritical carbon dioxide (SC-CO2) at pressures in the range of 15.2–35.4MPa and temperatures ranging from 308 to 348K, using a simple static method. The solubility values observed ranged from y=0.37×10−4 to 7.02×10−4 for DTX and y=0.32×10−5 to 15.88×10−5 for CPT. The mole fraction solubility of 5-FU was less than 10−6 and was not detectable by the proposed solubility determination method. The solubility values measured for pure drugs were correlated using semiempirical density-based models (Chrastil's, VA, Yu's, Gordillo's, Jouyban's, Bartle's, MST, KJ, and Tan's models). The results showed that these models, with an overall average absolute relative deviation (AARD%) lower than 21%, could be applied for satisfactory solubility prediction at different pressures and temperatures. Among different models, the Tan's equation is more suitable to describe the solubility of CPT and DTX in SC-CO2.

Measurement and correlation of antifungal drugs solubility in pure supercritical CO 2 using semiempirical models

In the present study the solubilities of two antifungal drugs of ketoconazole and clotrimazole in supercritical carbon dioxide were measured using a simple static method. The experimental data were measured at (308 to 348) K, over the pressure range of (12.2 to 35.5) MPa. The mole fraction solubilities ranged from 0.2 · 10 −6 to 17.45 · 10 −5. In this study five density based models were used to calculate the solubility of drugs in supercritical carbon dioxide. The density based models are Chrastil, modified Chrastil, Bartle, modified Bartle and Mendez-Santiago and Teja (M–T). Interaction parameters for the studied models were obtained and the percentage of average absolute relative deviation (AARD%) in each calculation was displayed. The correlation results showed good agreement with the experimental data. A comparison among the five models revealed that the Bartle and its modified models gave much better correlations of the solubility data with an average absolute relative deviation (AARD%) ranging from 4.8% to 6.2% and from 4.5% to 6.3% for ketoconazole and clotrimazole, respectively. Using the correlation results, the heat of drug–CO 2 solvation and that of drug vaporization was separately approximated in the range of (−22.1 to −26.4 and 88.3 to 125.9) kJ · mol −1.

Solubilities of some 9,10-anthraquinone derivatives in supercritical carbon dioxide: A cubic equation of state correlation

The solubilities of some 9,10-anthraquinone derivatives in supercritical carbon dioxide were measured at 308, 318, 328, 338 and 348 K over the pressure range from 15.2 to 35.5 MPa, using a simple static method. The solubilities were found to be in the range 8.1 × 10 −6 and 5.8 × 10 −4 mole fractions. The experimental results were correlated by the Peng–Robinson equation of state (PR-EOS) with the one and two adjustable parameter conventional mixing rules. The physical properties of pure components, critical temperatures and pressures and sublimation pressures were estimated using the group contribution methods. The proposed model was able to correlate the experimental solubility data with good agreement by adjusting binary interaction parameters k ij and l ij . Deviations of calculated results from experimental data were presented as averaged absolute relative deviation percentage, AARD (%), the values of which being in the range of 3.9–13.9%.

Measurement and Correlation of Solubilities of Some Disperse Azo Dyes in Supercritical Carbon Dioxide

The solubilities of three novel disperse azo dyes, ethyl 2-[6-{(E)-2-[4-(diethylamino)-2-methylphenyl]-1-diazenyl}-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl] acetate (Dye 1), ethyl 2-[6-{(E)-2-3-hydroxy-2-naphthyl-1-diazenyl}-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl] acetate (Dye 2), and 6-{(E)-2-[4-(diethylamino)phenyl]-1-diazenyl}-2-propyl-1H-benzo[de]isoquinoline-1,3(2H)-dione (Dye 3), in supercritical carbon dioxide were measured at T = (308, 318, 328, 338, and 348) K and various pressures in the range of (122 to 355) bar. The measurements were performed using a simple static method. On the basis of the obtained experimental results, the solubilities increased by increasing the density of supercritical CO2. Also, the solubilities of the dyes in supercritical CO2 at high pressure were decreased in the order of Dye 3 > Dye 1 > Dye 2, which parallels the order of their relative melting points. The higher the melting point, the lower the solubility. The mole fraction solubilities, y2, and solubilities, s, of the disperse dyes ranged from [(0.01 to 20.7)·10−6 and (0.01 to 15.8)·10−2] g·L−1, respectively. The solubility data were correlated using a semiempirical density-based Chrastil model with an overall average absolute relative deviation of 18.6 %. Using the correlation results, the enthalpy of CO2-dye solvation approximated in the range of (29 to 225) kJ·mol−1 for different dyes. The calculated results show satisfactory agreement with the experimental data.

Solubility of some statin drugs in supercritical carbon dioxide and representing the solute solubility data with several density-based correlations

Accurate experimental determination of a solid drug's solubility in supercritical fluids (SCFs) and its correlation is crucially important to the development of supercritical technologies for the pharmaceutical industry. In this work, the solubilities of lovastatin, simvastatin, atorvastatin, rosuvastatin and flovastatin in supercritical carbon dioxide (SC-CO 2) were obtained using a simple static method. The solubility measurements were performed at pressures in the range of 121.6–354.6 bar and temperatures in the range of 308–348 K. The mole fraction solubilities ranged from 1.12 × 10 −6 to 1.45 × 10 −3. Solubility data were correlated using four semi-empirical density-based models (Chrastil model, Bartle model, K–J model and M–T model). The results showed that by using three temperature-independent parameters these models can be applied for satisfactory solubility predictions at different pressures and temperatures. A comparison among the four models revealed that the Bartle and M–T models gave much better correlations of the solubility data with an overall average absolute relative deviation (AARD%) of 6.3 and 8.8%, respectively. Using the correlation results, the heat of drug–CO 2 solvation and that of drug vaporization were separately approximated in the range of 13.2–21.3 and 50.5–101.3 kJ/mol.

Investigations on the solubilities of some disperse azo dyes in supercritical carbon dioxide

The solubilities of three disperse azo dyes, 4-(N,N-dimethylamino)-4′-nitroazobenzene (D1), 4-(N,N-diethylamino)-4′-nitroazobenzene (D2) and Parared (D3) in supercritical carbon dioxide have been measured at different temperatures (308, 318, 328, 338, 348 and 358 K) and in the pressure range of 122–355 bar. The measurements were performed using a simple static method. As evidenced from the experimental results, the solubilities increase with increasing density of supercritical CO2. The solubilities in supercritical CO2 decrease in the order D2>D1>D3, which parallel the order of their relative melting points; the higher the melting point, the lower the solubility. The equilibrium solubility data were correlated using a semiempirical model. The calculated results show satisfactory agreement with the experimental data.

Comparative evaluation of coagulase-negative staphylococci (CoNS) adherence to acrylic by a static method and a parallel-plate flow dynamic method

The main goal of this work was to evaluate the adhesion to acrylic of several clinical strains of Staphylococcus epidermidis and Staphylococcus haemolyticus using both static and dynamic adhesion methods, and to compare the results obtained with these two methods. Adhesion was evaluated using the static slide method with different washing procedures, and the parallel plate flow chamber method. The extent of S. epidermidis adhesion, assessed by both methods, was greater than that of S. haemolyticus. The number of bacteria which adhered using the static method was lower than that using the dynamic method. It was found that the simple static method, when performed with an accurate washing procedure, can be as effective as the dynamic flow method for assessing differences in the adherence capacity of strains. Although the dynamic flow method yielded more overall information, its greater complexity and cost may not always justify its use for certain experimental comparisons. This investigation has shown that simple static adhesion methods, when performed accurately, can be used to evaluate differences in adhesion capacity.

Investigations on the solubilities of some disperse azo dyes in supercritical carbon dioxide

The solubilities of three disperse azo dyes, 4-( N, N-dimethylamino)-4′-nitroazobenzene (D 1), 4-( N, N-diethylamino)-4′-nitroazobenzene (D 2) and Parared (D 3) in supercritical carbon dioxide have been measured at different temperatures (308, 318, 328, 338, 348 and 358 K) and in the pressure range of 122–355 bar. The measurements were performed using a simple static method. As evidenced from the experimental results, the solubilities increase with increasing density of supercritical CO 2. The solubilities in supercritical CO 2 decrease in the order D 2>D 1>D 3, which parallel the order of their relative melting points; the higher the melting point, the lower the solubility. The equilibrium solubility data were correlated using a semiempirical model. The calculated results show satisfactory agreement with the experimental data.

Solubilities of Some Aminoanthraquinone Derivatives in Supercritical Carbon Dioxide

The equilibrium solubilities of four recently synthesized aminoanthraquinones in supercritical CO2 have been measured over a temperature range of 308 to 358 K and a pressure range of 122 to 358 bar, using a simple static method. The solubility data were correlated by a semiempirical model. The calculated results show satisfactory agreement with the experimental data.

A new simple static method for the determination of solubilities of condensed compounds in supercritical fluids

A simple static method based on gravimetric measurements has been adopted to measure the solubility of benzenecarboxylic acid, 2-hydroxy-benzenecarboxylic acid, 4-hydroxy-benzenecarboxylic acid and 1,8-dihydroxyanthraquinone along several isotherms in the temperature range 318–357 K and the pressure interval 7–23 MPa. Solubility data have been correlated with the Zieger–Eckert approach, using the Fedor atomic and group contribution method to estimate the solubility parameter and the molar volume of the solutes. A good agreement was obtained between data reported in the literature and those determined using the proposed method which allows one to measure solubility mole fraction as low as 10 −5. Provided that a suitable analytical technique is adopted the method can be extended also to multicomponent systems.

Solubility of dihydroxybenzene isomers in supercritical carbon dioxide

The equilibrium solubilities of dihydroxybenzene isomers pyrocatechol, resorcinol and hydroquinone have been measured in supercritical carbon dioxide using a simple static method. The measurements were performed in the pressure range from 120 to 400 atm at temperatures 35, 45, 55 and 65°C for pyrocatechol and resorcinol and in the pressure range from 120 to 200 atm at temperature 35°C for hydroquinone. The solubility of the isomers in supercritical CO 2 was found to vary in the order pyrocatechol>resorcinol≫hydroquinone. The experimental data were correlated by use of the density based model proposed by Chrastil.

The melting temperature, vapor density, and vapor pressure of molybdenum pentaflu oride

A sample of MoF 5 was prepared by reaction of MoF 6(g) and Mo(c). Melting curves of temperature against time established the melting temperature at zero impurity to be 318.85 K, the enthalpy of fusion to be 6.1 kJ mol −1 (±5 per cent), and the cryoscopic impurity of the sample to be 0.15 mole per cent. In the presence of MoF 6(g), which was added to suppress disproportionation, the vapor density of MoF 5 over the liquid was measured by the transpiration method at 343, 363, and 383 K, the total MoF 5 that evaporated being determined by permanganate titration. The total vapor pressure of MoF 5 oligomers over the liquid was measured by a simple static method at 373 and 392 K, while melting temperatures were taken alternately to monitor possible contamination of the sample. Although the vapor pressures were adjusted for disproportionation, solution of MoF 6 in MoF 5(1), and wall adsorption of MoF 6, their percentage uncertainty is probably several times that of the vapor densities. A combination of the two properties indicates the average extent of association of the saturated vapor to be near 2, which is the value for the dimer species (MoF 5) 2.

Evaluation of a simple static method for measuring vapor pressure

To complement transpiration and other methods when applied to partially dissociated or associated vapors, a direct static method was developed for measuring vapor pressures of around 1 kPa. A valve brings argon, originally at a little higher pressure, into direct contact with the pure vapor, whose pressure is very simply calculated from the reduction in pressure of the argon. Several types of systematic error were estimated; these include especially the effects of diffusion, viscosity, and steady-state gradients in gas temperature and molar mass, and indicate suitable dimensions of the capillary admitting the argon such that the vapor will remain confined essentially to its original volume during the time required for total-pressure equilibration. To test the method and apparatus, the vapor pressures of I 2 at 343 and 353 K (using saturated vapor) and that of MoF 6 at 237 K (using “superheated” vapor) were measured. The three mean values agree to better than 1 per cent with the most reliable published values, which themselves probably have absolute uncertainties this great. Further refinement of the method to give a general accuracy of 0.1 per cent seems feasible.

Piezoelectric Effect in Teflon Cable

Preliminary measurements of the piezoelectric effect in commercially produced Teflon cables have been performed using simple static methods. The effective piezoelectric constants for both uniaxial strain and torsional strain were determined. The effect, though 2–3 orders of magnitude smaller than those of good piezoelectric materials, is potentially useful as the basis of inexpensive but sensitive strain transducers.

The rigidity of solid unimolecular films

On evaporation at low temperatures of a benzene solution of palmitic or stearic acid on the surface of water an apparently solid film is left. The experiments of I. Langmuir and N. K. Adam have shown that these films are unimolecular in character, and inasmuch that they possess a fairly well defined melting point, although this varies with the acidity of the underlying solution, we may regard these films as unimolecular sheets of orientated solid acid. Anyone who examines these films even superficially cannot fail to notice their exceptional strength, all the more extraordinary when we consider their extreme thinness. Whilst the compressibility of such films, a property which can be readily determined by examination of the slope of the force area curve obtained with the well-known Langmuir trough apparatus, does not present any unusual features, being of the order anticipated for a hydrocarbon, yet we may expect that the coefficient of rigidity will be unexpectedly high. It seemed a matter of some importance to attempt to measure the rigidity of such films, by applying a suitable torque and determining the displacements effected, a method suggested to us by Prof. G. I. Taylor. In our preliminary experiments we endeavoured to employ a simple static method of placing a disc at the centre of a large circular film and applying torsion by means of a torsion head and wire on the disc to which a mirror is attached. We have to express our thanks to Prof. G. I. Taylor for the loan of an excellent and finely-calibrated head for this purpose. After numerous attempts with various modifications of the method we were reluctantly compelled to abandon it. The results were invariably the same; on applying a small torque to the disc no motion was visible on the image of the mirror attached to the disc. If the torque be increased the film is ruptured and the disc breaks loose and slips, generally forcing itself entirely from attachment to the film. Even with discs coated with wax or corrugated and milled on the circular edge no better results were obtained. Evidently the grip on the disc being only of one molecule thick is not sufficient to hold the slightest movement on the part of the shearing disc.