Canadian Field Soils I. Mineral Composition by XRD/XRF Measurements

Forty Canadian soils were laboratory tested for the presence of quartz and other minerals using X-ray diffraction/X-ray fluorescence techniques. On average, the highest quartz content was observed in soil samples from sites in Nova Scotia followed by Prince Edward Island sites, whereas soil sample from British Columbia sites had the lowest quartz content. The second most abundant mineral was albite that mainly occurred in soil samples from Ontario and Quebec sites. Illite was the third most abundant and prevailed in soils mainly from British Columbia and New Brunswick sites. Soil samples from British Columbia sites had the highest combined clay and silt content and were composed of illite, albite, kaolinite, and chlorite. The lowest clay content was found in the samples from the Quebec sites. The highest microcline (a potassium feldspar) content was observed in Quebec, Ontario, and Prince Edward Island sites. In contrast to other provinces, samples from Quebec and Ontario sites also included amphibole. Soil samples from Saskatchewan and Manitoba sites also comprised carbonates, i.e., calcite and dolomite. Iron oxides (e.g., goethite) were present in all soils, except the Quebec sites, but their occurrence was rather insignificant.     

Lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan as a new strategy for oral delivery of insulin: in vitro,ex vivo and in vivo characterizations

Objective: The purpose of this research was the development, in vitro, ex vivo and in vivo characterization of lyophilized insulin nanoparticles prepared from quaternized N-aryl derivatives of chitosan.

Methods: Insulin nanoparticles were prepared from methylated N-(4-N,N-dimethylaminobenzyl), methylated N-(4 pyridinyl) and methylated N-(benzyl). Insulin nanoparticles containing non-modified chitosan and also trimethyl chiotsan (TMC) were also prepared as control. The effects of the freeze-drying process on physico-chemical properties of nanoparticles were investigated. The release of insulin from the nanoparticles was studied in vitro. The mechanism of the release of insulin from different types of nanoparticles was determined using curve fitting. The secondary structure of the insulin released from the nanoparticles was analyzed using circular dichroism and the cell cytotoxicity of nanoparticles on a Caco-2 cell line was determined. Ex vivo studies were performed on excised rat jejunum using Frantz diffusion cells. In vivo studies were performed on diabetic male Wistar rats and blood glucose level and insulin serum concentration were determined.

Results: Optimized nanoparticles with proper physico-chemical properties were obtained. The lyophilization process was found to cause a decrease in zeta potential and an increase in PdI as well as and a decrease in entrapment efficiency (EE%) and loading efficiency (LE%) but conservation in size of nanoparticles. Atomic force microscopy (AFM) images showed non-aggregated, stable and spherical to sub-spherical nanoparticles. The in vitro release study revealed higher release rates for lyophilized compared to non-lyophilized nanoparticles. Cytotoxicity studies on Caco-2 cells revealed no significant cytotoxicity for prepared nanoparticles after 3-h post-incubation but did show the concentration-dependent cytotoxicity after 24?h. The percentage of cumulative insulin determined from ex vivo studies was significantly higher in nanoparticles prepared from quaternized aromatic derivatives of chitosan. In vivo data showed significantly higher insulin intestinal absorption in nanoparticles prepared from methylated N-(4-N, N-dimethylaminobenzyl) chitosan nanoparticles compared to trimethyl chitosan.

Conclusion: These data obtained demonstrated that as the result of optimized physico-chemical properties, drug release rate, cytotoxicity profile, ex vivo permeation enhancement and increased in vivo absorption, nanoparticles prepared from N-aryl derivatives of chitosan can be considered as valuable method for the oral delivery of insulin.     

怀化市食品包装用箬叶所属物种调查和7种元素含量测定

目的 对怀化市食品包装用箬叶所属物种开展调查,测定其中铜、锌、铅、镉、铬、汞和砷7种金属元素的含量,为制定食品包装用箬叶的安全标准提供基础数据。方法 以民间走访和标本采集的方法,调查怀化市13个行政县市区的食品包装用箬竹叶所属物种;以茶叶标准物质成分测定为质量控制方式,用原子吸收光谱法和氢化物发生原子荧光光谱法测定箬叶中铜、锌、铅、镉、铬、汞和砷7种金属元素含量。结果 通过调查和物种鉴定发现,怀化市食品包装用箬叶所属物种主要有5个,分别是阔叶箬竹、箬竹、美丽箬竹、广东箬竹和硬毛箬竹。箬叶中7种元素的含量差别较大,且与物种没有关联,锌含量为12.93～47.10 mg/kg,汞含量为0.012～0.94 mg/kg,铜含量为3.02～9.39 mg/kg,铬含量为2.10～15.96 mg/kg,铅含量为0.33～2.55 mg/kg,镉含量为0.015～0.37 mg/kg,砷含量为0.044～0.44 mg/kg。结论 怀化市食品包装用箬叶所属物种主要有5个,其中以阔叶箬竹分布最广,阔叶箬竹叶使用最广泛,箬叶中7种元素含量差别较大,该研究结果为箬竹栽培的物种选择和箬叶安全标准制定提供...     

J dominance in mixed mode loading

Elastic-plastic plane-strain crack problems subject to combined mode I and mode II loadings have been analysed with modified boundary layer formulations using the first two terms, K and T of the asymptotic elastic field. Corresponding full field calculations have been performed on geometries in which the mode I component arises largely from bending or tension and in which the T stress varies from tensile to compressive. The conditions for J dominance have been considered in terms of the effect of the T stress on the asymptotic field. As in related work on the pure mode I problem, positive T stresses are shown to favour J dominance, while compressive T stresses cause the stresses to fall from the HRR field.     

Influence of ion current on plasma electron temperature and density determined by probe methods

It is established that the electron temperature (T _e) of plasma as determined from the slope of the current-voltage (I-U) characteristic or from the second derivative of the probe current (Druyvesteyn method) is overstated. By taking into account the ion current contribution, it is possible to refine the T _e value determined from the slope of the I-U curve. Analysis confirms that the concentration of ions determined from I-U curves for a collisional regime in the near-probe space-charge region is also overstated.     

Chryseobacterium meningosepticum in a parapneumonic effusion in a chronic kidney disease patient on hemodialysis

Chryseobacterium meningosepticum is an uncommon human pathogen, which is an inhabitant of soil and water. It should be included in the list of suspected nosocomial infections, especially in patients with immunocompromised status. C. meningosepticum infections are not common but are clinically important because the organism is naturally resistant to multiple antibiotics. We report a case where the bacterium was isolated from the pleural fluid from a chronic kidney disease patient on hemodialysis, who developed pneumonia with complicated parapneumonic effusion. To the best of our knowedge, this is the first case where C. meningosepticum is isolated from the pleural effusion, from India.     

Liquid phase epitaxial growth of pure and doped GaSb layers: morphological evolution and native defects

Undoped and Te-doped gallium antimonide (GaSb) layers have been grown on GaSb bulk substrates by the liquid phase epitaxial technique from Ga-rich and Sb-rich melts. The nucleation morphology of the grown layers has been studied as a function of growth temperature and substrate orientation. MOS structures have been fabricated on the epilayers to evaluate the native defect content in the grown layers from theC-V characteristics. Layers grown from antimony rich melts always exhibitp-type conductivity. In contrast, a type conversion fromp- ton- was observed in layers grown from gallium rich melts below 400 C. The electron mobility of undopedn-type layers grown from Ga-rich melts and tellurium doped layers grown from Sb- and Ga-rich solutions has been evaluated. Paper presented at the poster session of MRSI AGM VI. Kharagpur. 1995     

Formation of microstructure resulting from quasi-peritectic reactions during freezing of Bi–Pb–Sn and Cu–Ni–Sn ternary alloys

Abstract

The quasi-peritectic reaction, frequently observed in ternary alloy systems, takes the form L + α?β + γ, where L indicates the liquid phase, and α, β and γ indicate solid phases. The formation of microstructure resulting from the kinetics of this reaction is considered from a theoretical point of view and compared with experimental observations of microstructures formed by quasi-peritectic reactions in two ternary alloy systems, Bi–Pb–Sn and Cu–Ni–Sn. Based on these considerations, an explanation is proposed for experimental observations previously reported in literature concerning phase transformations from the liquid in multicomponent ferrous alloys.     

Cellulosic solid films exhibiting cholesteric liquid crystalline order

Static tensile, dynamic mechanical, and stress relaxation properties of ethyl cellulose (EC) films cast from liquid crystalline and non-liquid crystalline solutions at various conditions were determined.EC films exhibited a marked tensile yield behaviour at room temperature. The yield stress depended on strain rate and an activated volumeV could be evaluated from the data of the yield stress. The dependence ofV obtained from the yield behaviour on the casting conditions was almost the same as that from creep behaviour.There was a phenomenological correlation between the dynamic modulusE and the activated volumeV: the higher the value ofE, the lower the value ofV; but there was no clear correlation between the relaxation modulus andV. From the stress relaxation behaviour,V was also evaluated; however, the dependence ofV evaluated from the stress relaxation data on the casting conditions was not similar to that from the creep or yield stress data.     

Effect of MgO Nano-oxide Additions on the Superconductivity and Dielectric Properties of Cu0.25Tl0.75Ba2Ca3Cu4O12?δ Superconducting Phase

The effect of MgO nano-oxide on both superconducting and dielectric properties of polycrystalline (Cu_0.25Tl_0.75)-1234 was studied. The MgO-content varied from x=0.0 up to 1.0 wt% of the sample’s total mass. The volume fraction of the prepared samples (x=0.0, 0.2, 0.6 and 1.0 wt%) was estimated from the room-temperature X-ray powder diffraction patterns. The superconducting transition temperature T _c, calculated from resistivity data, increased from 122 to 136 K as x increased from 0.0 to 0.8 wt% and then it decreased to 117 K for x=1.0 wt%. Also, the dielectric properties of all samples were measured in the frequency range from 100 Hz to 4 MHz at different temperatures from 113 to 300 K. The real part of dielectric constant ε′ was strongly dependent on both temperature and frequency for all x values. The imaginary part of dielectric constant ε″ and loss factor tan δ showed dispersion which shift toward lower frequencies with decreasing temperature. The ac conductivity σ _ac was derived from the admittance and sample dimensions in the same frequency range. It followed the power law σ _ac(ω)∼ω ^−γ with γ≈0.8.     

A Semiparametric Approach to the One-Way Layout

We consider m distributions in which the first m ? 1 are obtained by multiplicative exponential distortions of the mth distribution, which is a reference. The combined data fromm samples, one from each distribution, are used in the semiparametric large-sample problem of estimating each distortion and the reference distribution and testing the hypothesis that the distributions are identical. The approach generalizes the classical normal-based one-way analysis of variance in the sense that it obviates the need for a completely specified parametric model. An advantage is that the probability density of the reference distribution is estimated from the combined data and not only from the mth sample. A power comparison with the t and F tests and with two nonparametric tests, obtained by means of a simulation, points to the merit of the present approach. The method is applied to rain-rate data from meteorological instruments.     

On Jonckheere's k-Sample Test Against Ordered Alternatives

In this paper a k-sample non-parametric test for trend is considered. Given a sample of size n_i , i = 1, …, k respectively from each of k populations, the test rejects the hypothesis that the k populations are identical if S = Σ ^k _i=2 S_i ≥ S_i . Here Si is the Mann-Whitney statistic computed when each observation in the i-th sample is compared with the combined observations from the first (i – 1) populations. A recurrence formula is derived for computing the exact distribution of S. Tables of exact probabilities and critical values are given for nominal values of α = 0.5, 0.2, 0.1, 0.05, 0.025, 0.01, and 0.005 for k = 3 and all possible sample sizes from 2 to 8, and for equal sample sizes for values of n = 2(1)6, k = 4(1)6.     

Velocity of sound in solid hexagonal close-packed H2 and D2

Sound velocity measurements are reported on samples of hexagonal close-packed H₂ and D₂, believed to be single crystals. In the first part of the experiments, both the longitudinal and transverse velocities (v ₁ and v _t ) of crystals grown at a given melting pressureP _M were measured at 4.2 K. For each mode, the velocities plotted vs.P _M were found to lie between approximately parallel lines that represented the maximum and minimum observable velocities under the given experimental conditions set by the acoustic cell dimensions. From these extreme velocities v _1max, v _1min, v _tmax, and v _tmin an estimation of the elastic constants was made. Knowledge of these constants in turn permitted the calculation of the velocity surface, the bulk modulus, and the Debye temperature. In spite of the uncertainties in the analysis of the present data, a meaningful comparison could be made with results from other experiments. For both and D ₂ , the elastic constants are on the average 20% below those derived from neutron scattering data. The transverse velocities, both for H ₂ and D ₂ , are consistent with those of Bezuglyi and Minyafaev for polycrystalline samples, but the longitudinal velocities are about 10% smaller than those of these authors. The bulk modulus and the Debye temperature from our experiments are compared with those from equation-of-state and calorimetric experiments. In the second part of this research, we have investigated the temperature dependence of the sound velocities at constant volume for both H ₂ and D ₂ with low concentrationsX of molecules with rotational angular momentumJ=1. From the measurements in H ₂ , we are able to calculate the temperature change in the bulk modulus, which is then compared with that calculated from calorimetric data assuming the validity of the Grüneisen equation of state. Good agreement is obtained. In solid D ₂ , were were able to deduce the temperature dependence of the adiabatic and isothermal modulusc ₃₃ and make a rough estimation for that ofc ₁₃ . In the third part we present measurements of v ₁ and v _t at 42 K and at constant volume as a function ofX in solid H ₂ . It is found that as the orthopara conversion proceeds,v ₁ increases andv _t decreases. From these measurements the bulk modulus change withX is calculated. Comparison with the bulk modulus change calculated from static pressure measurements, assuming electric quadrupole-quadrupole interaction between the (J=1) molecules, shows very good agreement. The calculated dependence of the Debye temperature onX, as obtained from a combination of sound velocity and static measurements, is smaller than that reported from recent neutron scattering results. A short section is then devoted to absorption measurements in solid H ₂ , which gave only qualitative results. Finally, in Section 4, we present measurements of the sound velocity in liquid D ₂ at saturated vapor pressure as a function of temperature and for both liquid H ₂ and D ₂ along the melting curve.Work supported by grants from the National Science Foundation and from the Army Research Office, Durham.     

Saturated Liquid Densities for 33 Binary Refrigerant Mixtures Based on the ISM Equation of State

In this work, the ISM equation of state based on statistical-mechanical perturbation theory has been extended to liquid refrigerant mixtures by using correlations of Boushehri and Mason. Three temperature-dependent parameters are needed to use the equation of state: the second virial coefficient, B₂(T), an effective van der Waals covolume, b(T), and a scaling factor, α (T). The second virial coefficients are calculated from a correlation based on the heat of vaporization, ΔH_vap, and the liquid density at the normal boiling point, ρ_nb. α(T) and b(T) can also be calculated from second virial coefficients by a scaling rule. The theory has considerable predictive power, since it permits the construction of the PVT surface from the heat of vaporization and the liquid density at the normal boiling point. The equation of state was tested on 33 liquid mixtures from 12 refrigerants. The results indicate that the liquid densities can be predicted to at most 2.8% over a wide range of temperatures, 170–369 K.     

Solvable Brioschi Resolvents

 The Brioschi resolvent y ⁵ −10Zy ³ +45Z ² y−Z ² is a key component of an algorithm for calculating the roots of a general quintic polynomial. It is obtained from the general quintic polynomial by applying two Tschirnhausen transformations. In this paper it is shown that if the quintic polynomial is a solvable polynomial, then its associated parameter Z in the Brioschi resolvent satisfies Z=g(t) where g(t) is a rational function in ℚ(t) and t is chosen from an appropriate field. Received: July 23, 2001; revised version: October 14, 2002 Keywords: Solvable quintic, Brioschi quintic, resolvent sextic, parametrization. The author was supported by a research grant from the Natural Sciences and Engineering Research Council of Canada     

The minimum distance of parameterized codes on projective tori

Let X be a subset of a projective space, over a finite field K, which is parameterized by the monomials arising from the edges of a clutter. Let I(X) be the vanishing ideal of X. It is shown that I(X) is a complete intersection if and only if X is a projective torus. In this case we determine the minimum distance of any parameterized linear code arising from X.     

Superconductivity and Ferromagnetism of the Ru-1232 Compounds in the (Ru1?xNbx)Sr2(GdCe1.8Sr0.2)Cu2Oz System

The Ru-1232 compounds have been synthesized in the (Ru_1–xNb _x )Sr₂(GdCe_1.8Sr_0.2)Cu₂O _z system, and effects of Nb substitution for Ru on superconductivity and ferromagnetism of the Ru-1232 compounds have been investigated. First, X-ray powder diffraction study shows that nearly the single 1232 phase samples can be obtained in the x composition range from 0.0 to 0.3. Then, from the electrical resistivity study, it is found that each of the samples shows resistivity dropping phenomenon at two temperatures of T _c ^l and T _c ^h, which originates from superconductivity of the Ru-1232 phase and the Ru-1222 one, respectively. Both of the starting temperatures are lowering with increasing Nb content x. Lastly, from the magnetic susceptibility study, it is found that superconducting transition temperature T _c is 20 K for the Ru-1232 sample with x = 0.0 and the ferromagnetic transition temperature T _m is about 90 K. This study also shows that both of the values of T _c and T _m become low with increasing x from 0.0 to 0.3.     

Second-Order Derivatives of the Gibbs Energy for Liquid Mixtures of Alcohol + Heptane at Pressures up to 100 MPa

Second-order thermodynamic derivative properties, such as isobaric thermal molar expansions, isothermal and adiabatic molar compressibilities, and isochoric molar heat capacities of (ethanol, decan-1-ol, 2-methyl-2-butanol) +  heptane mixtures at pressures up to 100 MPa and in the temperature range from 293.15 K to 318.15 K were derived from experimental speed-of-sound u(T, p), density ρ(T, p = 0.1 MPa), and isobaric heat-capacity C _p (T, p = 0.1 MPa) data using appropriate thermodynamic relations. Excess values for the given properties were calculated according to the criterion of thermodynamic ideality of a mixture (Douhéret et al., Chem. Phys. Chem. 2, 148 (2001)), i.e., assuming that the chemical potential of component i in the ideal liquid mixture is equal to the chemical potential of component i in the mixture of perfect gases. The deviations from ideality for the mixtures under test have been explained in terms of the self-association of alcohols in solution which produces a strong departure from random mixing, the change in the non-specific interactions during mixing, and the packing effects.     

NMR relaxation measurements in solid H2 at low ortho-H2 concentrations

Nuclear transverse and longitudinal relaxation time measurements in solid hcp H ₂ are presented for two frequencies, 5.3 and 29 MHz. The ortho molefractionX varied from 2×10^–3 to 0.1 and the temperature range extended from 0.4 K to near the triple point, 13.9 K. Over this range ofX andT, the longitudinal timeT ₁is representative of theintramolecular relaxation processes that reflect the orientational fluctuations of the molecules. On the other hand, the rates fromintermolecular dipolar coupling are calculated to be negligible. At concentrationsX0.008, the transverse timeT ₂is dominated by the contributions from intramolecular relaxation processes, and is found to increase quite strongly with temperature. This new effect is ascribed to a coupling between molecular rotation and lattice vibrations, brought into evidence by the narrow width of the fluctuation spectral density at lowX. ForX>0.01 in the nondiffusion region, the NMR line shape is dominated by the signal from isolated ortho-H₂ molecules broadened via intermolecular dipolar interactions, and by the signal from isolated ortho pairs and triangles, etc., configurations. Above 9 K, however, the thermally activated diffusion produces an averaging out of these broadening effects, making it possible to determine theT ₂fromintramolecular nuclear spin interactions. For these mixtures,T ₁also shows a temperature variation, but with a maximum near 7 K and a flat minimum at higher temperatures. The relaxation data are compared with previous experiments and some systematic discrepancies in the dependence onX are found. The frequency dependence ofT ₁extends to higher concentrations than one expects from the theory of Fujio, Hama, and Nakamura, where nuclear relaxation is treated in terms of the orientational fluctuations from intermolecular electric quadrupolar coupling and crystalline fields. In the appendix, results are presented of an earlier attempt in this laboratory to determine the crystalline field splitting inH ₂from the temperature variation of the NMR line shape. An upper bound of |V _C/k _B|=0.028 K is obtained at zero pressure.Research supported by a grant from the AROD and the NSF.     

Dynamic J-R curves and tension-impact properties of AISI 308 stainless steel weld

In this paper, instrumented tension-impact (dynamic tensile) and instrumented Charpy impact test results for AISI 308 stainless steel welds at room temperature are reported. A few Charpy specimens precracked to a/W (crack length to width ratio) ratios of 0.42 to 0.59 were also tested. Dynamic yield strength obtained from tension-impact test agrees well with that from Charpy V-notch specimens. The strain rates obtained during the tension-impact test are compared with the various estimates of strain rates for V-notch and precracked Charpy specimens. A variation of the compliance changing rate method was necessary for determining the crack initiation point while crack growth was determined by power law key-curve procedure. J-R curves thus obtained from Charpy (precracked and V-notch) specimens are compared with those computed using handbook procedures using dynamic tensile results. Key words: Tension-impact testing, 308 stainless steel weld, Charpy V-notch, dynamic fracture toughness, dynamic yield strength, J-R curve, strain rate, key-curve.