THE DEVELOPMENT OF A MANDREL PEEL TEST FOR THE MEASUREMENT OF ADHESIVE FRACTURE TOUGHNESS OF EPOXY–METAL LAMINATES

A mandrel peel test is established for measuring the adhesive fracture toughness of a metal/rubber-toughened epoxy laminate system. By adopting an energy balance analysis it is possible to determine directly both adhesive fracture toughness and plastic work in bending the peel arm around the mandrel. The suitability of the procedure is examined for various types of metal peel arms, which are classified in terms of their ability to deform plastically during the test. The plastic work is also predicted theoretically, and comparisons are made between the measured and calculated values. The fracture energies determined from the mandrel tests are compared with those obtained from 90° fixed-arm peel tests. For the calculations of plastic work in bending in the fixed arm test, various options are used when modelling the tensile stress-strain behaviour of the peel arm material. In addition, the adhesive layer thickness is considered in terms of its influence on the calculation of adhesive fracture toughness.     

THE DIFFUSION COEFFlCIENT OF HEHEHP IN HEPTANE MEASURED BY THE MODIFIED STOKES CELL TECHNIQUE AT TEMPERATURES BETWEEN 25 AND 55°C.

The diffusion coefficient of HEHEHP in heptane has been measured by the modified Stokes cell technique at temperatures between 25 and 55^°C. The Stokes cell was calibrated by measuring acetic acid diffusion with the pH-stat technique. The average diffusion coefficient of HEHEHP in heptane was determined to be 0.97 × 10 ^?9 m²/s at 25 ^°C for HEHEHP concentrations of 0 - 0.1 kmol/m³. The diffusion coefficient did not vary significantly with HEHEHP concentration. The Wilke-Chane relationship was used to predict D values of 1.53 × lO^?9m²/s and 1.01 × 10 ^?9m²/s for the monomelic and dimeric species respectively. Comparison of the measured and predicted diffusion coefficients led to the conclusion that the HEHEHP was substantially dimenzed over the concentration range studied

An activation energy of 6.90 kJ/mol was calculated from the diffusion coefficient measurements at elevated temperature.     

AN INVESTIGATION ON THE MATHEMATICAL MODEL OF ELECTRODE DIFFUSION PROCESS IN THE DETERMINATION OF DISSOLVED OXYGEN BY POLAROGRAPHIC METHOD

The mathematical model of diffusion process in polarographic determination of dissolved oxygen hasbeen thoroughly studied with an electric simulator.It is found that the combination of microelectrodeand impulse operating technique is a possible way to improve the characteristics of present Clark electrode.The quantitative relations between the electrode size and operating condition are given in this paper indimensionless form,and the range of the optimum condition has been discussed.     

THE DETECTION OF POLYCYCLIC AROMATIC COMPOUNDS IN AIR SAMPLES BY GC×GC-TOFMS

Multidimensional Gas Chromatography-Time of Flight Mass Spectrometry is a relatively new, highly versatile and productive technique that is ideally suited for the detection of PACs in environmental samples. Air samples collected in Slocan Park in Vancouver and in Langley, BC (a semi-rural site) during the PACIFIC 2001 field study and aerosol samples from St. Anicet in Quebec (a rural site) collected in 2006 were analyzed for their PAC content. In addition to the parent PAH, many alkylated-PAH, oxygen, sulphur and nitrogen heterocyclic analogues of the parent PAH were detected. Many of the PAHs observed at these sites were also found in diesel exhaust.     

STUDIES ON THE RELATIONSHIP BETWEEN THE NETWORK STRUCTURE AND THE MECHANICAL PROPERTIES OF RUBBER VULCANIZATES (H) THE REINFORCEMENT OF ELASTOMERS BY CARBON BLACK FILLERS AND ITS CHARACTERIZATION

A satisfactory account of reinforcement of rubber through the application of the theory of elasticity forits vulcanizates with carbon black fillers has been obtained. A statistical theory of reinforcement by carbonblack fillers and its characterization was developed. Three methods for     

REVIEW OF RECENT ADVANCES IN TRANSITION AND LANTHANIDE METAL–DOPED GaN AND ZnO

Wide band gap semiconductors such as GaN and ZnO have continued to be at the forefront of spintronics research due to the demonstration of room-temperature ferromagnetism in these materials. A goal of this research is the fabrication of a spintronic device that may provide easy incorporation into existing GaN and ZnO technologies, higher integration density, and less power consumption that its electronic counterparts while achieving similar speeds. The progression of the ferromagnetic metals incorporated into GaN has moved from transition metals to rare earth metals such as the lanthanides. The properties of transition metal–doped ZnO thin films for the two most studied transition metal dopants, namely Mn and Co, are also discussed in this review.     

EFFECT OF SELECTED β-DIKETONES ON THE SYNERGICEXTRACTION OF COBALT(II) BY TRIPHENYL-PHOSPHINE OXIDE IN BENZENE

Abstract

Synergic extraction of Co(ll) by thenoyltrifluoroacetone (HTTA), Pivaroyltrilluoioacetone (HPvTA) or hexafiuoroacetylacetone (HHFA) mixed with triphenyiphosphine oxide (ph₃PO) in benzene from perchlorate media has been investigated. It ’ was found that in all the systems studied, Co(ll) is synergistically extracted as CoL₂.ph₃PO, where L stands for the different chelating ligands. The obtained equilibrum constants for the chelating and adduct systems indicated that: i- the weaker the acidity of the chelating ligand, the higher the overall aqueous phase formation constant of the metal chelate (β₂ ), ii- the sequence of the extraction constants (K_2,1 ) and the organic phase formation constants for the adduct ( β_2,1) as related to the chelating ligands is TTA> HFA > PvTA, iii- the stability of the adduct is related to both the structure and the pK_avalues of the chelating ligands.     

THE ROLE OF SOME COMPETITIVE ADSORBATES IN THE PREPARATION OF Pt/AI_2O_3 CATALYSTS WITH CONTROLLED Pt DISTRIBUTION BY IMPREGNATION

The results of adsorption equilibrium measurements show that the saturation adsorbed amounts (x/m)_Mof some organic acids increase in the following order:Acetic相似文献   

USE OF CROWN ETHERS AS SYNERGISTS IN THE SOLVENT EXTRACTION Of TRIVALENT ACTINIDES AND LANTHANIDES BY 1—PHENYL—3–METHYL—4 TRIFLUOROACETYL PYRAZOLONE—5

The synergistic extraction of trivalent Am, Cm, Cf and Eu with mixtures of 1—phenyl—3—methyl 1—4— trifluoroacetyl pyrazolone—5 ( HPMTFP) and a crown ether dicyclohexano—18—crown—6 (DCH18C6) or monobenzo—15—crown—5 ( B15C5) has been studied in chloroform. With DCH18C6 the synergistic species extracted are M(PMTFP)3 (HPMTFP) (DCH18C6) where N = Am, Cm and Eu and Cf ( PMTFP)3. (DCH18C6) whereas with B15C5 the species are M( PMTFP) 3.n( B15C5), n being 1 or 2 for all these metal ions. The possibility of high coordination numbere for theee metal ions in the above syeteme and the probable reaeone for the anbormel order of synergistic constants namely K2?81 have been discussed.     

STUDIES ON THE RELATIONSHIP BETWEEN THE NETWORK STRUCTURE AND THE MECHANICAL PROPERTIES OF RUBBER VULCANIZATES (Ⅰ) THEORY OF ELASTICITY FOR RUBBER VULCANIZATES WITH CARBON BLACK FILLERS IN LARGE DEFORMATION

A model structure formed by the combination of crosslinked, trapped entanglement and carbon black-polymer chain networks has been developed for rubber vulcanizates with carbon black fillers. Based on thisstructure and the proposed mechanism of large deformation, the elastic free energy     

USE OF BROMATE IN VOLUMETRIC ANALYSIS: IX,DETERMINATION OF ARSENIC AND ANTIMONY BY THE GYÖRY METHOD*

The determination of arsenic and of antimony by the oxidation of the hydrochloric acid solutions of their tervalent forms using standard bromate as oxidant by the Györy method has long been a preferred procedure. This method involves the use of strongly acid, hot solutions and nonreversible internal dye-stuff indicators. Difficulties result from the instability of the indicators under the required conditions. The published improvements as applied to the Györy method are discussed and evaluated. The new study of the old procedure shows that the use of a hot solution is not required. The experimental proof of this conclusion is given, and the use of the “electron beam sectrometer” and a modified “dead stop” equivalence-point determination has been applied to establish the concordance between the potentiometric and visual indicator applications. The performance of the various applicable internal indicators has been described and those preferred are specified.     

FACILE ANALYSIS OF CARBAZOLE IN COMMERCIAL ANTHRACENE BY HEAVY ATOM–INDUCED ROOM TEMPERATURE PHOSPHORESCENCE

The applicability of heavy atom–induced room temperature phosphorescence (HAI-RTP) in real samples is demonstrated in this work. In this methodology only two reagents, potassium iodide as heavy atom salt and sodium sulfite as oxygen scavenger, were used to obtain the phosphorescent signal of carbazole in solution while anthracene did not show phosphorescence under these experimental conditions. In this study a new simple, rapid, and selective phosphorimetric method is proposed, using HAI-RTP methodology for the determination of carbazole in high-purity anthracene. The phosphorescence intensity was measured at 438 nm with excitation at 290 nm. Phosphorescence was fully developed instantly. A linear concentration range between 0 and 250 ng/mL^?1 with a detection limit of 1.05 ng/mL^?1 (10.5 ng of CBZ in 600 ng of anthracene), an analytical sensitivity of 1.7 ng/mL^?1, and standard deviation of 0.71% at 150 ng/mL^?1 concentration level was obtained. The method has been successfully applied to the analysis of carbazole in spiked anthracene samples.     

SANS STUDY OF AGGREGATION OF THE COMPLEXES FORMED BY SELECTED METAL CATIONS AND P,P'-DI(2-ETHYLHEXYL) ETHANE- AND BUTANE-DIPHOSPHONIC ACIDS∗

ABSTRACT

The aggregation of several metal complexes formed during solvent extraction with P,P'-di(2-ethylhexyl) ethanediphosphonic acid, H₂DEH[EDP], and by P,P'-di(2-ethylhexyl) butanediphosphorac acid, H₂DEH[BuDP], in deuterated toluene, has been investigated by small angle neutron scattering (SANS). With H₂DEH[EDP], the extraction of Ca(II), La(IH) and U(VT) does not disrupt the cyclic hexameric structure of the ligand in solution. Fe(III) and Th(IV) complexes of H₂DEH[EDP], on the other hand, exhibit a very modest tendency to aggregate but only at very high metal loading in the organic phase. With H₂DEH[BuDP], the extraction of Ca(H), La(III), U(VI) and Th(IV) is not accompanied by significant aggregation of the metal complexes The Fe(HI)-H₂DEH[BuDP] complexes, however, form long cylindrical aggregates similar to those previously observed with P,P'di(2-ethylhexyl) methanediphosphonic acid, H₂DEH[MDP]. The aggregation behavior of the various metal-extractant species is discussed in light of the information obtained from earlier solvent extraction, vapor pressure osmometry, and infrared spectroscopy studies.     

THE DISTRIBUTION OF NOR-α-AMINOACIDS IN LIQUID TWO-PHASE TERNARY SYSTEMS FORMED BY SALTING-OUT OF LOW ALIPHATIC ALCOHOLS FROM AQUEOUS SOLUTIONS.

It is shown that the distribution of homologous series of nor-α-aminoacids in liquid two-phase three-component systems formed by salting-out of low aliphatic alcohols from their aqueous solutions by sodium chloride can be described by the following relation: 6nZ)=a + bln φ, where: D is the distribution coefficient expressed as the ratio of concentration of aminoacid in the upper and lower phases, respectively; φ is the ratio of alcohol concentration expressed in molar percent in the same phases; a and b are constants related to activity coefficients and salting-out constants of aminoacid and alcohol by sodium chloride.     

PREDICTION OF PRESSURE GRADIENT AND HOLDUP IN HORIZONTAL LIQUID–LIQUID SEGREGATED FLOW WITH SMALL EÖTVÖS NUMBER

This experiment utilized two-phase oil-water flows in a 26.1 mm diameter horizontal steel pipe to investigate segregated flow pattern. Data on pressure gradient and in situ phase distribution were obtained to come up with different combinations of phase superficial velocities, which ranged from 0.05 to 0.96 m/s. For the current liquid–liquid system having a small Eötvös number, we focused on identifying the effect of the interfacial tension and wall-wetting properties. Direct observation showed that oil and water started to mix when mixture velocity was increased. Also, at higher mixture velocities wherein the flows of two phases were initially separated, the droplets of one phase appeared in the mixed layer with negligible thickness. A closure relationship, which describes the interfacial mass transfer between liquid phases, was introduced into the framework of the two-fluid model. The model predictions agree well with the measured data. Similarly, an approach performance was evaluated based on the experimental data reported in previous literature.     

THE EXTRACTION OF SELECTED ACTINIDES IN THE ( III) (IV) AND ( VI) OXIDATION STATES FROM HYDROCHLORIC ACID BY Oπ D( iB) CMPO: THE TRUEX-CHLORIDE PROCESS∗

The extraction of tetravalent Th, Np, and Pu and hexavalent U from hydrochloric acid was studied using octyl(phenyl)-N,N-diiso-butylcarbamoylmethylphosphine oxides, 0π D(iB)CMP0 or CMPO, dissolved in tetrachloroethylene (TCE). A 0·5 MCMPO solution in TCE was found to be an extremely effective extractant for the tetravalent actinides and U(VI) from moderate to concentrated HC1. Extractant dependencies of the distribution ratios of Th(IV), U(VI), and Pu(IV) were 3rd, 2nd, and 3rd power, respectively, indicating the following species: ThCl₄’3CMPO, UO₂Cl₂2CMP0, and PuCl₄»3CMPO. The distribution ratios of a variety of non-actinide elements, including selected alkali, alkaline earths, Al, transition and post-transition metal ions were also measured from 2 Mand 6 M_ HC1. Based on the distribution ratios of tri-, tetra-, and hexavalent actinides from chloride media, a generic actinide extraction/recovery process was developed for the removal of actinides from chloride salt wastes. The process is called TRUEX-Chloride.     

THE SYNERGISTIC SOLVENT EXTRACTION OF RADIUM FROM ALKALINE NITRATE MEDIA BY DICYCLOHEXANO-21-CROWN-7 COMBINED WITH 2-METHYL-2-HEPTYL NONANOIC ACID EQUtUBRIUM REACTIONS AND METAL ION COMPETITION∗

The equilibria in the solvent extraction of radium from aqueous sodium nitrate/sodium hydroxide solutions by toluene solutions of dicyclohexano-21-crown-7 (DC21C7). 2-methyl-2-heptylnonanioc acid (HMHN). and mixtures of the two reagents are examined. The mixed reagents are synergistic in the extraction of radium and selective for radium over other alkali and alkaline earth elements. The dependencies of the extraction on pH and reagent concentration were utilized in computer modeling to estimate the stochiometry of the extracted complexes and equilibria involved the extraction. Three organic-phase species were identified in the extraction under basic (pH 11-13) conditions. With A = MHN^?. B = DC21C7 and assuming NaA is a 10-fold aggregate they are. RaA₂B.NaA. Log K = 3.57: RaA NaA. Log K = 0.99: and B 2NaA. Log K = ? 0.41. The effect of the presence of various concentrations of sodium     

THE MASS TRANSFER BEHAVIORS OF FE(Ⅲ), CO(Ⅱ) AND NI(Ⅱ) IN SULFURIC ACID WITH CYANEX302 BY USINGMICROPOROUS HOLLOW FIBER

In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.