True Path Research Articles

North Webster: A Photographic History of a Black Community.

Morris and Ambrose tell an embattled but triumphant story of strong families, old-time religion, and an emphasis on education as the true path to freedom. Extraordinary photographs. -- BooklistInformal photographs taken from family albums and collections provide a warm, intimate look at several decades of middle-class African-American life. -- Los Angeles Times Book Review... a fascinating history of the achievements and tribulations... of North Webster, a small African-American community in an upper middle-class suburb of St. Louis.A -- Journal of American History... a gloriously positive story which disproves past, present, and future notions that America's black population cannot effectively embrace love, family commitment, religious fervor, industriousness, career advancement, and academic achievement.A -- Julius K. Hunter, KMOV-TV Channel 4 News, St. LouisThis book should serve as an inspiration to people of all races. -- Gateway HeritageMore than 140 period photographs illustrate this history of a remarkable, successful black community near St. Louis. North Webster Grove is a black middle-class suburb which began at the end of the Civil War. Its residents have suffered the discrimination of a southern border state, and yet they accomplished great things.

Test of an Automatic Precision Guidance System for Cultivation Implements

By guiding implements accurately various field activities can be performed very precisely, such as row crumbling, band fertilizing, row spraying, drilling and hoeing. This means that no inputs are applied at places where they are not needed or would cause undue pollution of the environment. In the work reported here, the accuracy of a laser guidance system was examined when a hoe was used. On a level and slightly pressed band of soil approximately 1 m wide and full-field length, three paper sheets were spread with dimensions of approximately 15 m × 1 m. These pieces of paper were placed at approximately 35, 120 and 220 m from the laser transmitter. The centre element of the hoe carried a writing device, suspended to allow free vertical movement, which produced traces on the paper of the true path followed by the implement. Automatic guidance of an agricultural implement mounted on a vehicle by means of a side-shift facility, proved to be accurate within an average of ±6 mm on a track length of 220 m on arable land.

Graphics Based Humour: Its Contribution to Learning and Understanding

The educational use of humour, when it is used during live teaching, appears to be mainly that of maintaining attention and improving audience attitude. It may be unplanned, opportunist and driven by events, or consciously worked into a presentation, lecture or demonstration, nevertheless the quality, pertinence and effectiveness of the humour is very much due to the individual's sense of humour, timing and sensibilities.Some teacher's views on humour are that it is in some way divorced from learning (which is a properly serious thing) and only useful to alleviate boredom and stress. A typical response might run as follows:1. Humour is flippant, deconstructive and diverts from the true path of knowledge, 2. If this paper is about humour then it is going to be terribly dull, 3. OK then, make me laugh.This current research, which is at an early stage, is concerned with applications of textual and illustrative humour in teaching materials for 18–22 year old undergraduate students. It will consider the possibility that humour can positively contribute to understanding, creativity and learning, and whether an application model can be constructed to help teachers, authors and learners.

Validation of volume blood flow measurements using three-dimensional distance-concentration functions derived from digital x-ray angiograms.

The authors present phantom validation of a method for computing pulsatile flow waveforms in arterial vessels from high-frame-rate biplane x-ray angiograms. The three-dimensional course of a blood vessel is constructed from biplane digital x-ray angiograms. A parametric image of contrast mass versus time and true three-dimensional path length is generated. Adjacent contrast mass-distance profiles are matched to compute instantaneous velocity, which is multiplied by cross-sectional area to yield volume flow. An electromagnetic flowmeter was used to validate flow estimates in a phantom consisting of 150-mm tubes 3, 4, and 6 mm in diameter, orientated 15 degrees, 30 degrees, and 35 degrees to the imaging plane, with flow rates and waveforms expected in vivo. Mean and peak flows were accurate to within 9% and 10%, respectively, for velocities of less than 1 meter/second at a frame rate of 25 frames per second. A practical method for computing highly pulsatile flow waveforms in vivo in tortuous vessels is presented.

Heatline visualization of forced convection in porous media

The patterns of heatlines reported in this paper illustrate for the first time the true path of convective heat transfer through a saturated porous medium. Heatline patterns are reported for the following fundamental configurations: the boundary layer near an isothermal wall, the boundary layer near a wall with uniform heat flux, and the two-dimensional porous layer confined by two parallel plates. Emphasis is placed on the convection features that are being visualized for the first time by the heatline method, i.e., not by traditional methods such as the use of isotherms. It is shown that the heatlines of a flow in which the wall serves as heat sink are unlike the heatlines of the same flow with a wall that serves as heat source. The seepage flow with slip at the boundary is visualized by heatlines that leave a hot wall at an angle. The wall heat-flux distribution is visualized by the density of the heatlines that intersect the wall. The heatline pattern in fully developed flow of a pure fluid through a parallel-plate channel is also reported in order to emphasize that the pure-fluid pattern is not exactly the same as the pattern in the corresponding two-dimensional space filled with seepage flow through a porous medium.

Heatline visualization of forced convection laminar boundary layers

This paper reports in closed form the similarity heatfunctions H for laminar boundary layer flow on a flat wall. Plots of the constant-H lines (‘heatlines’) show that the path of convection from a hot free stream to a cold wall is unlike the path of convection from a hot wall to a cold fluid. The true path of convection in laminar boundary layer flow is visualized in charts drawn for both heat transfer modes (cold wall, hot wall), several Prandtl numbers (0.02, 0.72, 7) and isothermal walls and constant-flux walls. The paper stresses the heat transfer features that are brought into view for the first time by the heatline patterns. As a supplementary contribution, the paper reports the exact similarity solution for the wall with uniform flux in the Pr→ 0 limit, and proposes a closed-form local Nusselt number correlation that covers the entire Pr range.

A return to “converting the natives,” or antifoundationalist faith in the composition class

In 1976 Mina Shaughnessy invoked the phrase converting the natives (235) describe an undesirable attitude for a teacher of composition. In her article Diving In: An Introduction Basic Writing, she outlines four stages of development for composition teachers, of which converting the natives is the second. The tendency of teachers at this stage is see themselves as missionaries who initiate the unenlightened into the true path of correct writing. At this stage the teacher's goal is to carry the technology of advanced literacy the inhabitants of an underdeveloped country (235). Joseph Harris also mentions the term conversion in his 1989 critique of the use of discourse communities in the composition classroom (16). We have, Harris suggests, pictured various discourse communities as fundamentally different, in fact, so fundamentally different that we are at a loss explain how students make the break with former communities in order enter new communities. Harris describes the way we have tended think of students

Every recursive boolean algebra is isomorphic to one with incomplete atoms

The theorem of the title is proven, solving an old question of Remmel. The method of proof uses an algebraic technique of Remmel-Vaught combined with a complex tree of strategies argument where the true path is needed to figure out the final isomorphism.

Computation of floating mode delay in combinational circuits: theory and algorithms

Addresses the problem of accurately computing the delay of a combinational logic circuit in the floating mode of operation. (In this mode the state of the circuit is considered to be unknown when a vector is applied at the inputs.) It is well known that using the length of the topologically longest path as an estimate of circuit delay may be pessimistic since this path may be false, i.e., it cannot propagate an event. Thus, the true delay corresponds to the length of the longest true path. This forces one to examine the conditions under which a path is true. The authors introduce the notion of static cosensitization of paths which leads to necessary and sufficient conditions for determining the truth or falsity of a single path, or a set of paths. The authors apply these results to develop a delay computation algorithm that has the unique feature that it is able to determine the truth or falsity of entire sets of paths simultaneously. This algorithm uses conventional stuck-at-fault testing techniques to arrive at a delay computation method that is both correct and computationally practical, even for particularly difficult circuits.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An improved collapse axis on the R6 FAD for combined tension and bending loading

Experimental and computational studies were made of a number of single edge notch (SEN) specimens loaded through eccentric pins with notch depth ratios 0.21 and 0.52. It was found that as the applied load was increased the formation of a plastic hinge mechanism caused the ligament to shift sideways and in turn alter the ratio of bending to tension loading. The two different assumptions, constant and variable bending to tension ratio, gave very different paths in the moment-load ( M-Q) space, and failure lines when plotted on the R6 Fracture Analysis Diagram (FAD). An improved expression for normalized load, Sr, for SEN geometries under a linear loading system was obtained by including a plastic constraint factor in the uncreacked lower bound solution. For the pin-loaded SEN specimens under a non-linear loading system, it was shown that Sr based on ‘true path lengths’ in the yield diagram gave a failure curve which was in good agreement with the R6 Rev3 solution.

Period Paramount? A Critique of the Cohort Approach to Fertility

The aim of this discussion of cohort and period fertility estimation was to clarify the issue and resolve the conflict between 2 approaches. The typical view of these approaches is that fluctuations in period fertility represented in the total fertility rate (TFR) are due to the timing and pace of cohort fertility; these TFR changes distort. TFR appears high when the pace of cohort fertility increases. This tempo component of fertility must be removed through adjustment in cohort and period measures. Intercohort change reflects the true time path of fertility. The conventional view has been comprehensively discussed by such persons as Hajnal and others who have pointed out that age specific fertility rates are more consistent in period than in cohort analysis. The weight of statistical evidence supports the notion that all birth and marriage cohorts react as a single unit to the factors that determine the general level of fertility at that time. The cohort approach continues to be used because it offers more options for interpretation complements period analysis and has stronger arguments for its use. The resilience in the use of the cohort approach was examined historically by focusing on the demographic role of the cohort perspective and identifying the parts of current thinking on the demography of the period/cohort issue. Ryder has concertedly argued that fertility is affected by past reproductive history or life cycle stage that cohorts are distinctive that theories of fertility use a cohort framework that time series of cohort TFRs are smoother that the cohort framework is a natural approach to behavior and that changes in cohort fertility reflect changes in period amount. Several other views are indicated but the 6 arguments are discussed individually at some length. The problems with period fertility are indicated and an alternative approach to fertility measurement is presented: the period parity progression approach not as an index for a period but as the schedule of duration specific probabilities. The data issues and the role for the cohort method are discussed. The conclusion is that the confusion that has arisen is 2-fold: confusion between time trends in fertility and time trends in reproductivity. Confusion has also arisen due to Hajnals solution to short-term fluctuations in period fertility.

Discussion on Hercynian tectonometamorphic evolution of the Bosost dome (French–Spanish central Pyrenees)

R. L. Gibson writes: Pouget invokes a diapiric model for the development of structural–metamorphic domes in the Hercynian terrane of the Pyrenees. His model is based on conclusions drawn from the Bosost dome, namely that the core of this dome rose relative to the margins during regional metamorphism (deduced from P–T paths) and that the syn-metamorphic regional foliation formed in a dome-shaped attitude (from structural studies). Some comment is required, however, both on the methodology Pouget uses to construct the P–T paths presented in his paper and on his extension of the model to other domes in the Pyrenees. Pouget uses P–T estimates obtained from 4 garnet-bearing metapelite samples to construct P–T paths for different parts of the Bosost dome (fig. 4). Two P–T estimates were obtained from each sample using garnet core and rim compositions together with appropriate matrix phases and a straight-line vector was drawn linking the plotted results. Pouget maintains that this vector represents part of the P–T path followed by the sample during metamorphism. Such reasoning is, however, seriously flawed in that no guarantee exists that this straight line represents the true evolutionary path for the assemblage (see Spear et al. 1990 ). Pouget does not provide supplementary evidence, either from the analysis of continuous garnet zoning profiles or from the analysis of the metapelitic assemblages in terms of the KFMASH reaction grid (Harte &amp; Hudson 1979) to corroborate his ‘shortest-line’ assumption. Based on this assumption, Pouget discerns two types

Imaging with deep‐water multiples

Acquisition of on‐bottom hydrophone data recording of a near‐surface source provides an opportunity to treat water column multiples as useful signal. A ray‐equation based Kirchhoff depth migration is used to image primary reflections and deep‐water multiples recorded on an Ocean Bottom Hydrophone (OBH). The image of the subbottom sediments is shown to be improved by inclusion of the deep‐water multiple in the imaging process. Field data, jointly acquired by Woods Hole Oceanographic Institute and University of Texas Institute for Geophysics at Austin and consisting of an OBH (2300 m depth) recording a 10 800 cubic inch air gun array, are used to illustrate the feasibility of the technique. Images are obtained from both the primary reflections and from energy that has undergone an additional passage through the water column. Comparison of these images reveals an excellent correlation of reflectors with the predicted polarity reversal observed in the multiple’s image. Synthetic data are used to examine the difficulties in identifying the true path of the water column multiple. For flat‐layered media there are two different multiple paths — one that reflects beneath the source and one that reflects over the receiver — which have identical traveltimes. They do not, however, have the same amplitude, and it can be shown that their amplitudes differ sufficiently to allow a reliable image to be extracted from the energy that reflects over the receiver. As a final step, the image obtained from the multiple is corrected for the π phase shift from the free surface and added to the image from the primary reflection. This approach is limited to areas where water depths allow reliable separation of primary reflections from water column multiples. Application of this technique allows the utilization of coherent deep water multiples and results in both extended lateral coverage and an increased signal‐to‐noise ratio in the final image.

Kinetics and mechanisms of oxidation by metalions. Part XI(1). Kinetics of the osmium(VIII)-catalysed oxidation of glycols by alkaline hexacyanoferrate(III)

The kinetics of the OsVIII-catalysed oxidation of glycols by alkaline hexacyanoferrate(III) ion exhibits zerothorder dependence in [Fe(CN)63−] and first-order dependence in [OsO4]. The order with respect to glycols is less than unity, whereas the rate dependence on [OH−] is a combination of two rate constants; one independent of and the other first-order in [OH−]. These observations are commensurate with a mechanism in which two complexes, [OsO4(H2O)G]− and [OsO4(OH)G]2−, are formed either from [OsO4(H2O)(OH)]− or [OsO4(OH)2]2− and the glycol GH, or by [OsO4(H2O)2] and [OsO4(H2O)(OH)]− and the glycolate ion, G−, which is in equilibrium with the glycol GH through the reaction between GH and OH−. Hence there is an ambiguity about the true path for the formation of the two OsVIII-glycol complexes. A reversal in the reactivity order of glycols in the two rate-determining steps, despite the common attack of OH− ion on the two species of OsVIII-complexes, indicates that the two complexes are structurally different because ΔS‡ changes from the negative (corresponding to k1β1) to positive (related to k2).

Intrinsic reaction coordinate calculations for reaction paths possessing branching points

A 3-21+G energy surface corresponding to the proton transfer reaction in the hydroperoxyl anion solvated by one water molecule presents interesting topological features. In particular the intrinsic reaction coordinate that begins at the transition state does not lead to a minimum but to a saddle point of second order passing through two branching points. A new strategy to obtain the true reaction path in these cases is proposed.

Environmental Faust Succumbs to Temptations of Economic Mephistopheles, or, Value by Any Other Name Is Preference

In several of the chapters to his new book, Mark Sagoff begins by telling some story to frame the remainder. One of these is particularly significant for the book: Sagoff retells a New Yorker joke in which the Devil tells the new entrants to Hell that they are leaving right and wrong behind, and entering a world of mere preferences (p. 99). The Devil signifies for Sagoff the economics-oriented policy analyst, and the story is prophetic because by the end of the book, that old preference-counting Devil has caught up with Sagoff. The word appeared in the titles of several of the earlier essays on which the book is based,1 but the book has wisely subordinated that E-word to a subtitle; despite the frequent invocation of natural wonders and scenic areas, the book doesn't really focus on the environment until the last chapter. Nope, this book is about that other E-word, Economics, which is so favored by the Devil. More specifically, at least until that last chapter, the book is about how devilishly daffy economists are when they talk about the environment. Sagoff thinks their clever confusions are at best distracting and at worst antidemocratic (pp. 10, 95-97), and if we don't watch out, they are going to lead us off the ethical path and straight down the road to perdition. Up to the book's end, only an occasional grudging concession2 relieves the hellfire-and-brimstone economics-bashing. Consequently, dear Reader, you will be ill-prepared for that last chapter where, lo and behold!, it turns out that the true path to environmental paradise is through tradeable emission rights (pp. 209-10). What? What? Tradeable emission rights have been pushed for years by those diaboli-

Derivation of the electron inelastic mean free path from the elastic peak intensity

Measurements of the elastic peak intensity make possible estimation of the true inelastic mean free path (IMFP). Corresponding experiments are relatively simple and can be performed for any sample. The theoretical models can be used to derive the relation between elastic peak intensity and IMFP for single and multiple elastic scattering. In the present work both models were based on the differential scattering cross-sections calculated within the partial wave expansion method. Examples of calculations of the IMFP using both theoretical models are presented.

Moisture Intrusion in Sio2/Epoxy Interfaces

In-situ interfacial impedance measurements were used to study the effects of moisture at 80 ° C on the interface between oxidized silicon and a diglycidyl ether of bisphenol A (DGEBA) epoxy cured with diethylene triamine (DETA). Using two electrode configurations, admittances attributable to bulk and interfacial conduction processes were distinguished. Bulk impedance measurements followed Randles behavior; conduction in the bulk epoxy was ionic, and was diffusion controlled at low frequencies. Equivalent circuit models were used to demonstrate that an apparent interfacial conduction process was caused by distributed current leakage into the silicon subphase, not a true interfacial conduction path that would indicate water adsorption or interfacial aggregation. However, transitions in diffusivity and bulk epoxy permittivity behavior above a 70–80% relative humidity threshold were observed. Effective epoxy permittivity (εc) jumped to values indicative of a water cluster induced Maxwell-Wagner relaxation. The humidity threshold corresponds to a level that has been associated with adhesion loss in epoxies. It appears that epoxy adhesion losses result from bulk epoxy property changes at high humidity rather than interfacial bond displacement or delamination.

Moisture Intrusion in Sio2/Epoxy Interfaces

SummaryIn-situ interfacial impedance measurements were used to study the effects of moisture at 80 °C on the interface between oxidized silicon and a diglycidyl ether of bisphenol A (DGEBA) epoxy cured with diethylene triamine (DETA). Using two electrode configurations, admittances attributable to bulk and interfacial conduction processes were distinguished. Bulk impedance measurements followed Randles behavior; conduction in the bulk epoxy was ionic, and was diffusion controlled at low frequencies. Equivalent circuit models were used to demonstrate that an apparent interfacial conduction process was caused by distributed current leakage into the silicon subphase, not a true interfacial conduction path that would indicate water adsorption or interfacial aggregation. However, transitions in diffusivity and bulk epoxy permittivity behavior above a 70-80% relative humidity threshold were observed. Effective epoxy permittivity (∈c) jumped to values indicative of a water cluster induced Maxwell-Wagner relaxation. The humidity threshold corresponds to a level that has been associated with adhesion loss in epoxies. It appears that epoxy adhesion losses result from bulk epoxy property changes at high humidity rather than interfacial bond displacement or delamination.

Influence of Water-Desaturation Technique and Stress on Laboratory Measurement of Hydraulic Properties of Tight Sandstones

Summary Mercury porosimetry on unconfined sample chips and effective-gas-permeability measurements with evaporation used as the desaturating mechanism are two of the most common core-analysis measurements for tight sands. Data obtained with these two techniques have been compared with data on gas/water capillary pressure and effective gas permeability along a true drainage path at in-situ net confining stress. Results show that confining stress can have a significant effect on capillary pressure. Also, the use of evaporation to desaturate samples yields effective gas permeabilities much smaller than those obtained under true drainage conditions, suggesting that the evaporation method results in a pore-water distribution similar to that in an imbibition process.