Capillary forces in the acoustics of patchy-saturated porous media

A linearized theory of the acoustics of porous elastic formations, such as rocks, saturated with two different viscous fluids is generalized to take into account a pressure discontinuity across the fluid boundaries. The latter can arise due to the surface tension of the membrane separating the fluids. We show that the frequency-dependent bulk modulus $\tilde{K}(\omega)$ for wave lengths longer than the characteristic structural dimensions of the fluid patches has a similar analytic behavior as in the case of a vanishing membrane stiffness and depends on the same parameters of the fluid-distribution topology. The effect of the capillary stiffness can be accounted by renormalizing the coefficients of the leading terms in the low-frequency asymptotic of $\tilde{K}(\omega)$.Comment: 27 pages, 3 figure

Sabbatical Leave Proposal

I intend to study those aspects of planetarium education of which, at the time of the sabbatical, the college most urgently needs an understanding. I intend to do whatever is necessary to enable the Parkland Planetarium to commence successful operations in 1987. I also wish to attend meetings of those professional planetarium societies in which I hold membership, ·and to participate in two planetarium education workshops

Planning and policy implementation in the North St. Boniface community 1971-1985

69, [2], 3, 5, 13 leaves : maps ; 28 cm

Insider and Outsider Perspective in Ethnographic Research

Emic and etic perspectives are consequential for research because they impact the research process, the findings of a study, and the argument made by the researcher about the implications of these findings. Moreover, because the nature of ethnographic work involves the interpretation of cultures (Geertz, 1973), there is a responsibility on the part of the researcher to the culture being studied because the perspective the researcher takes impacts the knowledge produced about the cultural group that is studied.Contributors to this discussion represent a variety of research areas including rhetoric, library studies, family, media, and intercultural communication. Recurrant themes include awareness, bias avoidance, personal distance, appreciation of one\u27s insider/ outsider status

Rydberg and pulsed field ionization-zero electron kinetic energy spectra of YO

Journal ArticleA spectroscopic study of the Rydberg states of YO accessed from particular rotational levels of the A 2II1/2, v=0 state has been combined with a pulsed field ionization, zero electron kinetic energy (PFI-ZEKE) investigation. The results provide accurate values of the ionization energy of YO, ionization energy I.E.(YO)=49 304.316(31) cm-1 [6.112 958](4) eV], and of the rotational constant (and bond length) of the YO+ cation in its X 1?+, v=0 ground state, B0+=0.4078(3) cm21 [r0=1.7463(6) ?]. The improved value of I.E.(YO) combined with the known ionization energy of atomic yttrium then leads to the result D0 0 (Y+-O)2D0 0 (Y2O=0.1041?0.0001 eV. Combining this result with the value of D0 0 (Y+-O) obtained from guided ion beam mass spectrometry yields an improved value of D0 0 (Y+O)=7.14?0.18 eV. The PFI-ZEKE spectra display an interesting channel-coupling effect so that all rotational levels with J+?J'(A)+0.5 are observed with high intensity, where J+ is the angular momentum of the YO+ cation that is produced and J'(A) is the angular momentum of the A 2II1/2 state that is reached when the first photon is absorbed. This is thought to result from the interaction between the dipole moment of the rotating YO+ core and the Rydberg electron, which can induce changes in l and J+ subject to the dipolar coupling matrix element selection rule, ?J+=?1, ?l=?1. The channel-coupling mechanism also appears to induce an inverse autoionization process in which an unbound electron with a low value of l is captured either by its low-J+1 YO+ cation or by a second YO+ cation with the same value of J+. This inverse autoionization process is extremely sensitive to the electron kinetic energy, leading to narrow peaks in the PFI-ZEKE spectrum which are only slightly broader than the laser linewidth employed for this study (0.25 cm-1)

Off campus : developing co-operative housing for students

vi, 31 p. ; 28 cm.Based on the study: Off campus : a report on the feasibility of developing co-operative housing for students near the University of Winnipeg

Rental housing supply in Winnipeg : a spatial profile

xx, 141 p., [28] p. : map

Averaging of moment condition estimators

We establish the consistency and asymptotic normality for a class of estimators that are linear combinations of a set of √ n-consistent estimators whose cardinality increases with sample size. A special case of our framework corresponds to the conditional moment restriction and the implied estimator in that case is shown to achieve the semiparametric efficiency bound. The proofs do not rely on smoothness of underlying criterion functions