THE IDIOSYNCRASIES OF SPEED

The history of photography has produced a fascinating wealth of theoretical narratives. However, a surprising proportion of existing narratives relies on a rather problematic assumption: that it is possible and appropriate to equate photography and vision. In this article, I demonstrate that this questionable equation depends on certain physical circumstances and particular technological operations dictated thereby, and mediated by various constraints of speed. I dwell on a number of strategic moments in the history of photography for a critical reading of these circumstances, the applications and the interpretations of various types of speed, and their relationship to photography. This article concludes with the claim that in recent decades, one important type of speed, namely shutter speed, has undergone a transformation that now makes it possible to challenge the ontological model binding vision and photography together. The probable disappearance of the shutter in the near future, moreover, retrospectively opens up an alternative media history of photography that renounces the traditional hierarchy in which photographic images are less important than the technological and conceptual systems producing them.     

An integrated numerical simulator for thermal performance assessments of firefighters’ protective clothing

Research and development of firefighters’ protective clothing relies on a large number of fire disaster experiments in order to assess the thermal performance. It would be substantially advantageous to substitute a virtual numerical experiment for a real one in terms of time, cost and safety. The present article reports the development of an integrated numerical simulator that makes possible the estimation of burn injuries originating from fire disasters. In the simulator, a general-purpose computational fluid dynamics program computes the fluid flow and heat transfer in an in situ fire event, while a one-dimensional program calculates the radiative–conductive heat transfer through the clothing and human skin. A data interface combines the two simulations by loose coupling so as to give the real-time burn injury progress output. The predicted surface heat fluxes and burn degrees agree with experimental measurements reasonably well. Possible numerical error sources are discussed that call for potential improvements in the future.     

Trajectory control of incompletely restrained parallel-wire-suspended mechanism based on inverse dynamics

This paper discusses parallel wire mechanisms where an end-effector of the mechanism is suspended by multiple wires. The mechanisms enable not only three-dimensional (3-D) positioning but also 3-D orienting of the end-effector, unlike typical wire suspension-type mechanisms such as overhead crane. To discuss the parallel-wire-suspended mechanisms generally, two forms of basic dynamic equations are presented. Then the parallel wire mechanisms are classified into two types based on the basic equations. Dynamical properties of the two types of wire-suspended positioning mechanism are discussed. In this paper, one of the wire-suspended mechanism, incompletely restrained-type parallel wire mechanism, is mainly discussed on its inverse dynamics problem and its trajectory control problem. The inverse dynamics problem for the incompletely restrained-type mechanism plays an important role on its control problem, because the mechanism has low stiffness based on incomplete constraints on the suspended object which is governed by its dynamics. The paper proposes an antisway control method for the suspended object. In the method, the inverse dynamics calculation is used for nonlinear dynamics compensation to control the suspended object of the incompletely restrained parallel wire mechanism.     

A surface motor-driven planar motion stage integrated with an XYθZ surface encoder for precision positioning

This paper describes a surface motor-driven XY planar motion stage equipped with a newly developed XYθ_Z surface encoder for sub-micron positioning. The surface motor consists of four linear motors placed on the same surface, two pairs in the XY-axes. The magnetic array and the stator winding of the linear motor are mounted on the platen (the moving element) and the stage base, respectively. The platen can be moved in the X-direction by the X-linear motors, and in the Y-direction by the Y-linear motors. It can also be rotated about the Z-axis if the X- or Y-linear motors generate a moment about the Z-axis. The surface encoder consists of two two-dimensional angle sensors and an angle grid with two-dimensional sinusoidal waves on its surface. The angle grid is mounted on the platen of the stage which is levitated by air-bearings. The angle sensors and the air-bearing pads are fixed on the stage base so that the motion of the platen is not affected by the electronic cables and air hoses. The XY-positions and θ_Z rotation of the platen can be obtained from the angle sensor outputs with resolutions of approximately 20 nm and 0.2′′, respectively. The surface encoder is placed inside the stage so that the stage system is very compact in size. Experimental results indicate that precision positioning can be carried out independently in X, Y and θ_Z with resolutions of 200 nm and 1′′, respectively.     

Flow profile and void fraction of granular solids in a moving bed

In the system consisting of spheres of uniform size flowing downwards with a constant head through a vertical tube, the flow pattern and the void fraction of the descending particles were measured. The particles showed both a constant-velocity region in the central core of the bed and a shear region in the outer section of the core. On the basis of plasticity theory, the boundary surface between those two regions was approximately predicted with the aid of some assumptions. Concerning the void fraction of flowing solids, some interesting results were obtained and they were discussed by considering the “vibratory effect” that results from the random motion of individual particles in the shear region.     

New strategies for aspiration pneumonia

Aspiration pneumonia is associated with decreases in both swallowing and cough reflexes and is the most common cause of death in the elderly. Basal ganglia strokes might predispose these patients to develop pneumonia owing to reductions of both reflexes, resulting in frequent aspiration during sleep. An impairment of dopamine metabolism in the basal ganglia is observed in these patients and levodopa administration improves the impaired swallowing reflex. Both swallowing and cough reflexes are mediated by endogenous substance P (SP) released from vagal sensory nerves in the pharynx and upper airways. The addition of a low dose of capsaicin to liquid or food, which stimulates the release of SP, may help prevent aspiration pneumonia. Angiotensin-converting enzyme inhibitor decreases SP catabolism resulting in improvements in both reflexes. Oral care and the sitting position after meals may decrease aspiration pneumonia in the elderly.     

Pulmonary tuberculosis in the elderly

Clinical problems of pulmonary tuberculosis in the elderly patients were discussed. As for diagnosing tests, chest X ray sometimes shows atypical findings in patients with pre-existing pulmonary diseases (i.e. pulmonary emphysema, interstitial pneumonia and etc). It is most important to get bacteriologic evidence from suspected patients of pulmonary tuberculosis. Elderly patients have co-existing diseases except pulmonary tuberculosis. Controlling co-existing diseases is essential for treatment of pulmonary tuberculosis in the elderly patients. Treatment with standard chemotherapy leads to good result even in the elderly. However, we have to investigate the mechanism of rush cases, who dies in a few months in spite of adequate chemotherapy.