Discrete choice in commuter space: Small area analysis of diurnal population change in the Tokyo Metropolitan Region

Considerations of metropolitan commuting have often related to urban space as a continuum, and to commuting itself as a process. This approach has led to escalating complexity in the measurement, modeling and analysis of commuting, often with no commensurate results. The present study extends an alternative approach that considers commuter space of a metropolis as a discrete set of small areas. Each small area throughout the metropolis is a nighttime location of some households and, as a possible discrete destination choice of individuals within households, each subarea is also a daytime location of some persons. Each subarea, therefore, may be thought of as attaining two values, corresponding to its daytime (e.g., noontime) and nighttime (e.g., midnight) populations. The diurnal demographic shift of subareas, as a set of binary events, or toggles, between daytime and nighttime populations, is associated with commuter access throughout the metropolis. Diurnal shift offers structural simplicity aimed at estimating small-area daytime populations across a metropolitan region that might suitably precede and complement conventional continuum considerations of commuting. Using data for the Tokyo Metropolitan Region, we identify average household size as the nighttime indicator of small-areas, and daytime population density as their daytime indicator. The potential for the estimation of daytime populations across metropolitan regions where daytime population data are unavailable, is underscored by the clear tendency towards inverse relation of these two indicators of diurnal shift.     

The role of continuity in residual-based variational multiscale modeling of turbulence

This paper examines the role of continuity of the basis in the computation of turbulent flows. We compare standard finite elements and non-uniform rational B-splines (NURBS) discretizations that are employed in Isogeometric Analysis (Hughes et al. in Comput Methods Appl Mech Eng, 194:4135–4195, 2005). We make use of quadratic discretizations that are C ⁰-continuous across element boundaries in standard finite elements, and C ¹-continuous in the case of NURBS. The variational multiscale residual-based method (Bazilevs in Isogeometric analysis of turbulence and fluid-structure interaction, PhD thesis, ICES, UT Austin, 2006; Bazilevs et al. in Comput Methods Appl Mech Eng, submitted, 2007; Calo in Residual-based multiscale turbulence modeling: finite volume simulation of bypass transition. PhD thesis, Department of Civil and Environmental Engineering, Stanford University, 2004; Hughes et al. in proceedings of the XXI international congress of theoretical and applied mechanics (IUTAM), Kluwer, 2004; Scovazzi in Multiscale methods in science and engineering, PhD thesis, Department of Mechanical Engineering, Stanford Universty, 2004) is employed as a turbulence modeling technique. We find that C ¹-continuous discretizations outperform their C ⁰-continuous counterparts on a per-degree-of-freedom basis. We also find that the effect of continuity is greater for higher Reynolds number flows.     

On the weld strength of in situ tape placed reinforcements on weave reinforced structures

Unidirectionally reinforced thermoplastic tapes were welded onto woven fabric reinforced laminates using a laser assisted tape placement process. A mandrel peel setup was used to quantify the interfacial fracture toughness between the tape and the laminate as a measure for weld strength. The tape placement process was compared to a conventional press molding process in terms of interfacial fracture toughness. The tape placed specimens were found to outperform the press molded specimens. Additional experiments were performed to investigate the influence of the degree of crystallinity and the process induced weld interface on the measured fracture toughness.     

Design of polymeric dispersants for waterborne coatings

Block and random copolymers of ammonium methacrylate and dimeth-ylaminoethyl methacrylate have been synthesized and tested as dispersants of various organic and inorganic pigments in formulations for waterborne paints. Blockiness of the co-monomer distribution is a prerequisite for good color characteristics in the final paint. It is however noteworthy that a tapered diblock (one-step anionic synthesis), a diblock copolymer with a regular change in composition from one block to the other one, has an interfacial activity quite comparable to the parent “pure” diblock copolymer (two-step anionic synthesis). The most interesting observation is that the poly(dimethylaminoethyl methacrylate) anchoring block can impart stability to dispersions of pigments as different as iron oxide, a blue Cu-phthalocyanine pigment, and a red organic pigment based on pyrrole in representative aqueous paint formulations. This type of diblock copolymer is promising for the design of universal dispersants. Center for Education and Research on Macromolecules (CERM), Sart-Tilman, B6, 4000 Liège, Belgium. Rijksstraatweg 31, P.O.Box 3, 2170 BA Sassenheim, The Netherlands.     

Beyond imprisonment of meaning: Technology facilitating redefining

Defining is a natural and necessary response to an ambiguous world, but causes fixation of categories and perspectives. On the basis of two earlier studies of project groups, we came to argue that redefining, and hence constructing various ways in which one perceives and understands something, enables groups to overcome imprisonment in meaning, establishing continuous development and flexibility. In this article, we first build a rationale for facilitating a process of redefining, to be taken into account when designing technology. Departing from this rationale, we discuss features of groupware technology that permit change by being flexible, and evoke redefining by engaging the user more actively. In so doing, we argue to think along new lines in the design of communication and collaboration technology. This paper proposes a specific perspective on technology, facilitating groups to engage in a productive, creative fashion of exploiting meaning potential.     

On the complexity of drawing trees nicely: corrigendum

In this journal, Supowit and Reingold [1] have given a proof that it is NP-complete to decide whether a binary tree can be drawn on a grid with width 24 if certain æsthetic requirements are obeyed. We identify and repair a mistake in their proof.Received: 19 November 2003, Published online: 21 April 2004     

Preparation of concentrated platelet suspensions by dehydration against polyethyleneglycol 20,000

Thirty-two patients, 28 women and 4 men aged from 17 to 57 years were treated surgically for obesity. Their body weight ranged from 90 to 184 kg, with an excess weight from 42% to 180%. In 6 cases the Salmon operation and in 26 the Payne-de Wind operation were performed. Two patients died. In the remaining cases the postoperative course was uneventful and relatively mild. The longest follow-up period was 22 months. Weight loss rate was highest in the first period after the operation and the monthly rate of the weight loss in the first year after the operation was 3.5 to 6 kg. Diarrhea disappeared usually after 4 months. In some patients a transient fall in serum potassium and calcium level was observed. Other favorable results included a significant fall in the serum levels of cholesterol and beta-lipoproteins and improved value of BSP retention test. The condition of the patients is good and they have returned to work.     

A Methodology Based on Pulse-Velocity Measurements to Quantify the Chemical Degradation Levels in Thin Mortar Specimens

In this research, ultrasonic pulse echo measurements are used to quantify through thickness chemical degradation in thin mortar specimens. The degradation level is predicted using the time of travel of the acoustic wave through the thickness of the structure. The front and back wall interaction reflections are used to obtain additional information from very early stage degradation. The pulse-velocity of sound waves as a function of the thickness of the layers within the structure is described. With knowledge of the pulse-velocity in pristine and fully degraded conditions, it is possible to determine the complete range of degradation length over the layer thickness. The method is applicable for leaching of calcium and acidic attack. The acoustic measurements were verified with destructive testing. The correlation between the acoustic and non-acoustic experiments agree with the described pulse-velocity and degraded depth function. The method based on ultrasonic measurements can be implemented in other thin-layered structures.