Visual perception of absolute distance (between an observer and an object) is based upon multiple sources of information that must be extracted during scene viewing. The viewing duration needed to fully extract distance information, particularly in navigable real-world environments, is unknown. In a visually-directed walking task, a sensitive response to distance was observed with 9-ms glimpses when floor- and eye-level targets were employed. However, response compression occurred with eye-level targets when angular size was rendered uninformative. Performance at brief durations was characterized by underestimation, unless preceded by a block of extended-viewing trials. The results indicate a role for experience in the extraction of information during brief glimpses. Even without prior experience, the extraction of useful information is virtually immediate when the cues of angular size or angular declination are informative.
Although there are many well-known forms of visual cues specifying absolute and relative distance, little is known about how visual space perception develops at small temporal scales. How much time does the visual system require to extract the information in the various absolute and relative distance cues? In this article, we describe a system that may be used to address this issue by presenting brief exposures of real, three-dimensional scenes, followed by a masking stimulus. The system is composed of an electronic shutter (a liquid crystal smart window) for exposing the stimulus scene, and a liquid crystal projector coupled with an electromechanical shutter for presenting the masking stimulus. This system can be used in both full-and reduced-cue viewing conditions, under monocular and binocular viewing, and at distances limited only by the testing space. We describe a configuration that may be used for studying the microgenesis of visual space perception in the context of visually directed walking.Visual space perception research has identified a variety of stimulus cues that specify absolute distance (between an object and an observer) and relative distance (between two objects). This research has populated a list of cues that includes binocular parallax (the stimulus to convergence), binocular disparity, relative motion parallax, angular declination, linear perspective, texture gradients, and so forth (Sedgwick, 1986). More recently, research has been aimed at understanding how visual space perception is used to control actions-behaviors directed at objects and locations in the nearby environment. For example, in the visually directed walking paradigm (or, simply, blind walking), participants view a target, then cover their eyes and attempt to walk to the remembered target location without further visual input (Thomson, 1980(Thomson, , 1983. In well-lit, natural viewing conditions, performance in this task is typically quite accurate and precise out to at least 22 m (e.g., Loomis, Da Silva, Fujita, & Fukusima, 1992). This good performance has been interpreted by several authors as indicating that the initial target location was perceived accurately (Loomis, Da Silva, Philbeck, & Fukusima, 1996;Philbeck, Loomis, & Beall, 1997).How long does it take the visual system to extract the spatial information needed to control spatially directed behaviors? Does extraction of information proceed at the same speed for all visual cues, or are some cue combinations processed faster than others? These questions are crucial for understanding how vision is used to control behavior, but, as yet, the answers are largely unknown. In this article, we describe a system that can be used to address a wide variety of fundamental issues surrounding the microgenesis of visual space perception.
The Kelvin-Plank statement of the Second Law of Thermodynamics states that work cannot be taken from a constant temperature reservoir without putting energy in first. This means a device cannot be built that produces work from ambient air temperature without a constant supply of work or heat into the device. However, this paper presents the analysis of a particular coupling of two cycles that appears to do just that. The machine combines two thermodynamically matched cycles: a heat-pump cycle and a Rankine cycle. Each cycle runs the other, with the net result being shaft work available to the ambient and an exhaust product of cold air. The only input to the machine is 12°C air from the ambient atmosphere. The heat-pump uses ammonia as the working fluid, absorbing heat from ambient atmosphere and supplying heat to the Rankine engine boiler. The Rankine cycle expansion engine uses propane as the working fluid, and supplies shaft work to power the heat-pump compressor. Using standard, well-known analysis, the net result is a machine that, once started, supplies work and cold air to the ambient with no further work input. Under ideal analysis, the heat-pump operates with a coefficient of performance of 6.85 and the Rankine cycle operates with an efficiency of 21%. Multiplying these gives a combined cycle efficiency of 1.44. The heat-pump superheater operates at an average temperature of −44°C, with a mass flow rate of 1.00 kg/s. It absorbs 106 kW of heat from ambient temperature air and supplies that heat to the Rankine cycle boiler. The Rankine cycle expansion engine has a mass flow rate of 2.51 kg/s, and produces 364 kW of work. Of this, 254 kW is supplied to the heat-pump compressor, 4 kW to the Rankine cycle feed-pump, and the remaining 106 kW of work to the ambient. This equals the heat extracted from the ambient; there is no unexplained creation of energy. All analysis was performed from standard engineering text books, and all thermodynamic data was taken from common industry charts. The cycles are common and well known, and the temperatures, pressures, and expansion ratios well within believable values. The analysis has been peer reviewed and no errors found. Yet when these two cycles with these two working fluids are combined, the result is net work to the environment and cold air, with no work or heat input. The authors do not believe the second law is flawed. We expect an error will be discovered, either in our analysis or in the thermodynamic tables of the two fluids that we used. We present the analysis and result in the hopes of having the error pointed out.
This paper describes a theoretical device called a Petroleum Synthesizer, which absorbs the greenhouse gas carbon dioxide from the atmosphere and converts it into a synthetic petroleum fuel. The device has four parts: First, a CO2 Scrubber using sodium carbonate reversibly absorbs CO2 from the atmosphere. Simultaneously, a Hydrogen Generator separates water electrolytically to produce hydrogen (H2). Third, a Carbon Monoxide Generator mixes the H2 and the CO2 over a nickel catalyst, changing the constituents into carbon monoxide (CO) and water. Finally, the CO and additional H2 are combined in a cobalt-catalyst Fischer-Tropsch (F-T) Processor to produce gaseous and liquid petroleum products. Calculations show that one watt of electricity supplied for one year would allow the Synthesizer to create 0.420 kg of petroleum products, and absorb 1.314 kg of CO2 from the atmosphere. An acre of solar voltaic panels powering Synthesizers could produce 46,000 kg, or about 14,000 gallons, of petroleum products per acre per year, and absorb 140,000 kg of CO2. By contrast, an acre of corn produces less than 400 gallons of ethanol per year.
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