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This paper describes an experimental program of study on the sliding characteristics of Teflonstainless steel interfaces. The effects of normal pressure, sliding distance, normal pressure history, sliding velocity, sliding velocity history, normal pressure rate, and sliding work are identified and interpreted. Test results show that the friction force is independent of the normal pressure history and the sliding velocity history, and is also irrelevant to the normal pressure rate. In addition, the dependence of dynamic friction force on the normal contact pressure and the sliding velocity can be uncoupled. The dynamic friction force can be determined by multiplying the quasistatic friction force by an amplification factor. The reciprocal of the quasistatic friction coefficient is linearly dependent on the normal pressure only, and the amplification factor is solely a function of velocity. Moreover, the dynamic friction force decays during sliding, and the decaying is a function of excess dynamic sliding work.

This paper reports the dynamic responses of a onefifthscale gableframe structure composed of tapered members subjected to El Centro earthquake ground motions, using a shaking table. The test structure was designed according to the American Institute of Steel Construction AISC working stress design method. The widththickness ratio of the flange and the depththickness ratio of the web of the members satisfy the requirements of a compact section. The unbraced length also meets the criteria for a compact section based on the dimensions of the shallowend cross section. Failure of the test structure is due to lateral buckling of rafters. No local buckling prior to the lateral buckling is observed. The experimentally determined ultimate strength of the test structure is compared with those predicted by the codes AISC load and resistance factor design LRFD, AS 1250, and BS 5950. The experimental results are also compared with those of a similarly designed gable frame composed of prismatic members, tested under similar conditions.

In this paper, the guide specifications for bridge base isolation published in 1991 by the American Association of State Highway Transportation Officials (AASHTO) are briefly summarized and discussed. The effective stiffness and equivalent damping ratio given in the AASHTO isolation specifications are evaluated. Based on this study, it is concluded that the equivalent damping ratio determined using the AASHTO procedure may decrease with respect to the increase of the inelastic deformation of leadrubber bearings. In addition, the equivalent damping ratios calculated for a singledegreeoffreedom system subjected to a generated AASHTO design earthquake may be larger than 30% for a wide fundamental period range. As a result, a threedimensional inelastic timehistory analysis as required by the AASHTO provisions may be necessary. However, to require a threedimensional inelastic timehistory analysis could be a dilemma for the current bridge engineering design practice. As an alternate approach, an empirical method is proposed for the determination of the effective period shift and equivalent damping ratio.

In the United States, design of steel gable frames normally follows the guidelines prescribed by the American Institute of Steel Construction for assumed wind and gravity loadings. In this study, a pinnedbase steel gable frame structure composed of prismatic members is constructed, and the dynamic characteristics of that structure are investigated using the shaking table. The tests are carried well into the inelastic range so that ultimate lateral strength under seismic excitation can be quantified. It is observed that for such structures the response modification factor adopted by the Applied Technology Council ATC should be assumed with caution. In addition, the excessive elastic and inelastic story drifts, which are attributed to the pinnedbase condition, require careful evaluation to ensure structural safety against large sidesways. The excessive story drift is likely one of the major reasons for the severe nonstructural damage of steel gable frames during the 1985 Chile earthquake and the 1987 Edgecumbe earthquake.

For over a decade, bisphosphonate administration has evolved and become the cornerstone of the prevention and treatment of fragility fractures. Millions of post-menopausal women have relied on, and continue to depend on, the long-acting, bone density-maintaining pharmaceutical drug to prevent low-energy fractures. In return, we have seen the number of fragility fractures decrease, along with associated costs and emotional benefits. However, with any drug, there are often concerns with side effects and complications, and this unique drug class is seeing one such complication in atypical subtrochanteric femoral fracture, counterproductive to that which it was designed to prevent. This has created concern over long-term bisphosphonate administration and its potential link to these atypical fractures. There is controversial evidence surrounding such a definitive link, and no protocol for managing these fractures. This review offers the latest information regarding this rare but increasingly controversial adverse effect and its potential connection to one of the most successful forms of treatment that is available for the management of fragility fractures.

The syntheses of two nanoporous nickel phosphates, VSB-1 and VSB-5, have been investigated to elucidate the effect of various synthesis parameters such as pH, type of base, reaction time, and heating method. The pH is found to be the most important factor to direct the structure in the synthesis. These molecular sieves are easily synthesized in a suitable pH range even without organic template molecules. VSB-1 is crystallized only in acidic conditions (pH = 3.5−4.8), while VSB-5 is prepared in weakly basic conditions (pH = 7.5−9.2). The reaction yield of VSB-1 increases with increasing pH, while VSB-5 shows the opposite trend. Compared with conventional hydrothermal synthesis, the microwave irradiation method increases the reaction rates of the two nickel phosphates by about 60 times, and the synthesis of VSB-1 and VSB-5 can be completed within 1 min at 190 and 180 °C, respectively. It is demonstrated that the molecular sieves can be synthesized continuously under microwave irradiation due to these fast crystallizations.

Pentacene films with submicron thickness, deposited by molecular beam deposition, were fabricated and characterized using X-ray diffraction, atomic force microscopy, and Raman spectroscopy. Organic thin-film transistors (OTFTs) were fabricated on a p-type silicon substrate, using an active layer of highly ordered small pentacene molecules grown at room temperature. Pentacene film was aligned using the photoaligned polyimide method, which is usually employed to align liquid crystals. Improved field-effect mobility, in the range 0.4−0.75 cm²/V·s, was obtained in pentacene-based OTFTs with photoaligned polyimide layers in which the pentacene molecules were aligned parallel to the direction of the transport of the carriers. The mobility was improved when the current flowed parallel or perpendicular to the orientation of the pentacene films with anisotropic ratios of 2.7−8.3. The thin-film structures of pentacene on the photoaligned polyimide surface depend on the dose of UV light that irradiates on the polyimide surface. X-ray analyses reveal that the structure of the highly ordered pentacene films includes only a single “thin-film phase”, generated by optimizing the energy of irradiation of the photoaligned polyimide. However, the poorly aligned films include two phases:  a “single-crystal phase” and a “thin-film phase”.

An analytical model for high damping elastomeric isolation bearings is presented in this paper. The model is used to describe mathematically the damping force and restoring force of the rubber material and bearing. Ten parameters to be identified from cyclic loading tests are included in the model. The sensitivity of the ten parameters in affecting the model is examined. These ten parameters are functions of a number of influence factors on the elastomer such as the rubber compound, Mullins effect, scragging effect, frequency, temperature and axial load. In this study, however, only the Mullins effect, scragging effect, frequency and temperature are investigated. Both material tests and shaking table tests were performed to validate the proposed model. Based on the comparison between the experimental and the analytical results, it is found that the proposed analytical model is capable of predicting the shear force–displacement hysteresis very accurately for both rubber material and bearing under cyclic loading reversals. The seismic response time histories of the bearing can also be captured, using the proposed analytical model, with a practically acceptable precision. Copyright © 2002 John Wiley & Sons, Ltd.

This paper presents a new beamforming technique, in which ultrasound waves are focused at the display pixels on the Cartesian coordinates, rather than sampling points located on the uniformly-separated scanlines on either the polar or Cartesian coordinates. Consequently, this method does not require a digital scan converter (DSC) and therefore completely eliminates the distortions due to the DSC. A new imaging system based on the proposed method is also presented, which is advantageous over conventional systems in hardware complexity, especially when high-density imaging is required. The new method can also be used effectively to achieve high frame rates for real-time 3D imaging and cardiac applications. To verify the proposed method, we modified a commercial ultrasound scanner and performed experiments with a 3.5MHz convex array and a 7.5MHz linear array. The experimental results with in vivoand in vitrodata show that the proposed technique provides much smoother and finer images than the conventional dynamic focusing methods.

Analysis of frass extracts and aerations from adult beetles confirmed earlier studies identifying 1-heptanol as a principal pheromone constituent produced by female Dendroctonus jeffreyiHopkins. The aerations also indicated that males produced 33% (+) and 67% (−)-frontalin, previously unreported for this species, and >99% (+)-exo-brevicomin. Both males and females were responsive to these compounds in electrophysiological studies. Laboratory bioassays and field trapping experiments indicated that males and females were attracted to a mixture of 1-heptanol plus the principal host resin component heptane, but females were less attracted than males. Inclusion of racemic exo-brevicomin at 0.1% concentration in the traps increased the response of females. Inclusion of racemic frontalin above a 1% concentration in the normally attractive lures blocked arrival of beetles to the traps. While the female-produced pheromone components and host synergists are very different between the sibling species D. jeffreyiand Dendroctonus ponderosaeHopkins, the principal male-produced compounds are the same, and the response of the female beetles to those compounds appears to be similar.

If f(z) = Σckznk, where nk+1/nk⩾ q > 1, and f(z)is analytic in |z| < 1, the f(z)is an annular function if and only if sup |ck| = ∞. This answers a question posed by L. R. Sons and D.M. Campbell simplifies the proofs of many known examples of annular functions.

Let $ \mathcal{D}(\rho )$f in the unit disc $ \Delta $ and there exists an arc $ {\Upsilon _f} \subseteq \partial \Delta $ $ \vert{\Upsilon _f}\vert \geqslant \rho $ $ \underline {\lim } \vert f(z)\vert \geqslant 1,z \to \tau \in {\Upsilon _f}$ $ \{ \left\Vert f \right\Vert = {\sup _{z \in \Delta }}\vert f'(z)\vert(1 - \vert z{\vert^2})\} $ $ \mathcal{D}(\rho )$ $ f \in \mathcal{D}(\rho )$ $ {z_f} \in \Delta $

For any fixed $ 0 &lt; \rho &lt; 2\pi ,\mathcal{D}(\rho )$ which satisfy (i) $ f(0) = 0$ $ {\underline {\lim } _{z \to \tau }}\vert f(z)\vert \geqslant 1$ lying on some arc $ {\Gamma _f} \subseteq \partial \Delta $ $ \vert{\Gamma _f}\vert \geqslant \rho $ $ f \in \mathcal{D}(\rho )$ $ {z_f} \in \Delta $

$\displaystyle \vert f'({z_f})\vert(1 - \vert{z_f}{\vert^2}) \geqslant \frac{2}{e}\frac{{\sin (\pi - (\rho /2))}}{{(\pi - (\rho /2))}}.$ In this paper we improve this estimate by replacing the quantity $ \pi - (\rho /2)$ $ \theta (\rho )$ $ \pi - (\rho /2)$ $ \theta (\rho )$ .

After Choquet (see Brelot and Doob [6, p. 404]), we recently have presented an alternative answer of Doob's problem [8] by showing that there is a Blaschke product $ B$. In our construction, the zeros of lie on both the first and fourth quadrant. Naturally, we may ask if a product having the same property, but having zeros which lie on only one quadrant, can be constructed. We show that the answer to this question is no for the minimal fine topology, but yes for the ordinary one. There is a significant difference between these two topologies in function theory.

Following Doob, we say that a function $ f(z)$ has the property $ K(\rho )$ and for some arc $ \gamma $ 0$ --> $ \left\vert \gamma \right\vert \geqslant 2\rho > 0$

Recent measurements on the V2O5-GeO2 glass system consisting of an equimolar mixture of V2O5 and GeO2 revealed that increase in electrical conductivity of these glasses upon annealing could be attributed to the increase in V4+ and V3+ content which accompanied the microstructure formation. In the present work we report a similar study on V2O5-TeO2 and V2O5-P2O5 glass systems. It was found that in tellurite glass V3+ content increased upon annealing and V4+ content remained unchanged. In phosphate glass some increase in V4+ and no significant change in V3+ contents were observed. V3+ and V4+ contents in glasses could be best estimated from optical and electron paramagnetic resonance spectra, respectively.

1-Heptyne and 2-heptyne were reacted with Mo(CO)6 (M=Cr, Mo, W) under different conditions. All samples exhibit ESR signals only in the presence of spin traps. Both carbon-centered and metal-centered radicals have been observed. The radical intermediates were identified by isotropic g-values and splitting constants for nitrone spin adducts obtained from the reaction systems under various conditions.

This paper describes an experimental program of study on the sliding characteristics of Teflon‐stainless steel interfaces. The effects of normal pressure, sliding distance, normal pressure history, sliding velocity, sliding velocity history, normal pressure rate, and sliding work are identified and interpreted. Test results show that the friction force is independent of the normal pressure history and the sliding velocity history, and is also irrelevant to the normal pressure rate. In addition, the dependence of dynamic friction force on the normal contact pressure and the sliding velocity can be uncoupled. The dynamic friction force can be determined by multiplying the quasi‐static friction force by an amplification factor. The reciprocal of the quasi‐static friction coefficient is linearly dependent on the normal pressure only, and the amplification factor is solely a function of velocity. Moreover, the dynamic friction force decays during sliding, and the decaying is a function of excess dynamic sliding work.

Using the spin probe predeuterated-2,2,6,6-tetramethyl-4-piperidone-N-oxide (PD-Tempone) at mole fractions about 10-5 the transition temperatures of «pure' 4-cyano-4'-n-pentylbiphenyl (5CB) and four dilute solutions of 3,3-diethylpentane (Et4C) at mole fractions between 0.02 and 0.08 in 5CB were determined. This fast approach relies on the smaller coupling constant obtained for the spin probe in the orientationaly ordered nematic phase relative to the isotropic phase. Using an especially designed sample holder in conjunction with a temperature control and monitoring system the temperatures of our samples were controlled to within ± 0.02 °C. The results were used to obtain the phase diagram for the 5CB- Et4C system in the concentration range studied.

Early in the sixties, Joseph L. Doob proved that if $ f(z)$ It was pointed out by the referee that Choquet was the first one to show that the converse of the above theorem is false. His example was published by Brelot and Doob (see [2, p. 404]). Recently, the referee suggests the question as to whether a bounded analytic function can actually have an angular limit but not a fine limit. We construct a Blaschke product which has the fine cluster value 0 and the angular limit 1 at the same boundary point. This answers both questions of Doob and the referee.

For a function $ f$, and for each $ \lambda > 0$ $ L\left( \lambda \right) = \left\{ {z \in D:\left\vert {f\left( z \right)} \right\vert = \lambda } \right\}$. We introduce a class $ \mathcal{L}$ $ \left\{ {L\left( {{\lambda _n}} \right)} \right\}$ $ \left\{ {{\lambda _n}} \right\}$ $ {\mathcal{L}_1}$ $ \mathcal{L}$ $ {A_\infty }$ $ {e^{i\theta }}$ has $ \infty $ $ F\left( f \right)$. We prove that for a function $ f$ $ {\mathcal{L}_1}$ is an arc of the unit circle such that $ \Gamma \cap {A_\infty } = \emptyset $ belongs to .

AbstractIn this work we demonstrate that if ? Rn(n? 3) is either a half space or a unit ball, and if E? then Eis an ordinary thin set at a boundary point of ? (including the point at infinity if ? is a half space) if and only if it is a full-thin set at the corresponding Kuramochi boundary point of ?. The case for n= 2 has already been considered in an earlier work.1980 Mathematics subject classification (Amer. Math. Soc.): 31 B 05.

Gale and Shapley have an algorithm for finding a stable marriage in a system of preferences. Recently, Dubins and Freedman have extended this result by showing the theorem that honest is the best policy, that is, no coalition of boys can simultaneously improve their fates by lying about their preferences. Their algorithm is quite complicated and therefore the main object here is to give a short proof of this "Honest Theorem".

Various equivalent elastic models specified in current bridge engineering practices for the seismic analysis of base-isolated bridges are summarized and evaluated. Two additional methods proposed by the California Department of Transportation (CALTRANS) are validated based on their predictions of the maximum inelastic seismic responses of base-isolated bridges. The CALTRANS proposed methods are implemented with an empirical model for the determinations of the effective stiffness and equivalent viscous damping ratios of isolation units and base-isolated bridges. A modal strain energy method combined with the concept of component energy ratio is utilized to formulate the “composite damping ratio” of an entire base-isolated bridge. A five-span regular bridge subjected to four design earthquakes and ten recorded ground motions is employed to investigate the accuracy of prediction using various equivalent elastic methods.

We construct a sequence $ \left\{ {{a_n}} \right\}$ $ {a_n} \to 0,\sum {\left\vert {{a_n} - {a_{n - 1}}} \right\vert &lt; \infty } $ $ f(z) = \sum {{a_n}{z^n}} $85 (1982), 335-341).

In the United States, design of steel gable frames normally follows the guidelines prescribed by the American Institute of Steel Construction for assumed wind and gravity loadings. In this study, a pinned‐base steel gable frame structure composed of prismatic members is constructed, and the dynamic characteristics of that structure are investigated using the shaking table. The tests are carried well into the inelastic range so that ultimate lateral strength under seismic excitation can be quantified. It is observed that for such structures the response modification factor adopted by the Applied Technology Council (ATC) should be assumed with caution. In addition, the excessive elastic and inelastic story drifts, which are attributed to the pinned‐base condition, require careful evaluation to ensure structural safety against large sidesways. The excessive story drift is likely one of the major reasons for the severe nonstructural damage of steel gable frames during the 1985 Chile earthquake and the 1987 Edgecumbe earthquake.

The transitional behaviour of binary mixtures, each containing a non-mesomorphic quasi-spherical solute at a low mole fraction in a nematogenic solvent, has been investigated by E.S.R. spectroscopy using 4-oxo-2,2,6,6-tetramethyl-4-piperidinyl-1-oxy (tempone) as a spin probe. This approach makes use of the smaller coupling constant obtained for the spin probe in the orientationally ordered nematic phase relative to that obtained in the isotropic phase. The solutes included Et4C (tetraethylmethane) and R4Sn (R = Cb2bH5, n-C3H7 and nCb4H9). The solvents were 4-n-pentyl-4'-cyanobiphenyl (5CB) 4-n-hexyl-4'-cyanobiphenyl (6CB) and 4-n-heptyl-4'-cyanobiphenyl (7CB). This fast approach compares favourably with other studies. In addition it provides the tempone spectral parameter, f, which is a relative measure of the fraction of the nematic phase at different temperatures within the two phase region.

ABSTRACTThe feasibility of the use of a petroleum vacuum-distillation residuum as a feedstock for carbon applications was investigated using a semicontinuous supercritical propane (C3H8) extraction system. Experiments were carried out under different conditions to ascertain the effects of system pressure and temperature on the yields of extracted oils and the properties of residual pitches. The extraction residue obtained near the critical temperature and over the critical pressure of propane solvent showed appropriate properties as a precursor pitch for carbon materials, representing superior yields, high asphaltene contents, low toluene insolubles and the adequate softening point of 401-424 K. The extraction yields of deasphalted oil were increased as the system pressure was increased corresponding to the increased density of propane solvent. No difference in the yields and properties of residual pitches were observed at the experiments performed in the vicinity of the critical temperature of propane.