Design of a Legged and Clamper-Based Capsule Robot with Active Locomotion Function

This paper presents a legged and clamper-based capsule robot with active locomotion function. The capsule robot (CR) utilizes the extension and contraction of the anchoring legs to expand the collapsed intestinal wall, crawl in the intestinal tract, and stand in large spaces such as the stomach and large intestine organs. The mechanical structure design, kinematic analysis, principle of locomotion and force analysis of the CR are presented. The design concept and locomotion principles of the proposed CR are verified by a prototype with the diameter of 13 mm and length of 39 mm. Three experiments were conducted to test the locomotion performance of the proposed CR. In the experiments, the prototype successfully expands the collapsed phantom intestine, stands on the plane and moves forward in transparent tube at a promising speed. Experimental results indicate that the CR has good locomotion capabilities.

Personality traits covary with individual differences in inhibitory abilities in 2 species of fish

In a number of animal species, individuals differ in their ability to solve cognitive tasks. However, the mechanisms underlying this variability remain unclear. It has been proposed that individual differences in cognition may be related to individual differences in behavior (i.e., personality); a hypothesis that has received mixed support. In this study, we investigated whether personality correlates with the cognitive ability that allows inhibiting behavior in 2 teleost fish species, the zebrafish Danio rerio and the guppy Poecilia reticulata. In both species, individuals that were bolder in a standard personality assay, the open-field test, showed greater inhibitory abilities in the tube task, which required them to inhibit foraging behavior toward live prey sealed into a transparent tube. This finding reveals a relationship between boldness and inhibitory abilities in fish and lends support to the hypothesis of a link between personality and cognition. Moreover, this study suggests that species separated by a relatively large phylogenetic distance may show the same link between personality and cognition, when tested on the same tasks.

Optimizing root measurements in rhizotrons

Background and AimsThe line intersect method is widely used in rhizotron and minirhizotron studies to quantify roots and study cultivar and treatment differences in root growth. We investigated ways to optimize the line intersect method and root depth measurements with respect to data variability and the time spent on counting roots.MethodsRoot intensity was measured with three different grid patterns and different lengths of counting line on 2 m long transparent tube rhizotrons. Rooting depth was recorded by measuring the depth of the deepest root and by measuring the depth below which 5, 10 and 25 roots were observed.ResultsFor root intensity the coefficient of variation (CV) was reduced 10-50 percentage points for grids that distributed counting lines equally across the measured area compared to using a restricted centralized area. In addition, the CV approached an asymptote of around 40 % when more than 50 root intersections per grid were observed. Further we show that recordings of the deepest root gave the most variance and least difference between means with a p-value of 0.65 for difference between cultivars. In contrast, a significant difference between cultivar rooting depths (p = 0.01) was found when using the depth below which 25 roots were observed.ConclusionWe propose the use of grid designs adapted to different root densities to decrease time spent on counting roots at high root intensities, and minimize data variability at low root intensities. Further on rooting depth measurements including more roots may be a more useful parameter statistically to reveal variety or treatment differences in rooting depth.

Динамика горения пропан-воздушной газовой смеси при ее поджиге стримерным сверхвысокочастотным разрядом

The results of experimental studies of combustion of propane–air gaseous mixture when it was ignited by a microwave discharge have been described. The mixture with different propane content fills a sealed radio-transparent tube placed along the axis of a focused linearly polarized quasi-optical microwave beam at atmospheric pressure. Multi-point ignition of the mixture is carried out near one end of the tube by a pulsed microwave discharge with a surface-developed streamer structure. The growth of gas pressure in the tube as propane burned was recorded in the experiments. The microwave pulse energy being invested in high-temperature discharge plasma has been estimated in them. The minimum percentage of propane in the mixture at which the microwave discharge ignites it has been determined in experiments. The time dependence of the pressure increase in the tube as the propane burns determines the combustion process dynamics.

Innovative flat-plate solar collector (FPC) with coloured water flowing through a transparent tube

Light absorption rates depends on the color of a substance. In this study, a new type of FPC was suggested, which utilizes the light absorption rate of the working fluid passing through a transparent collecting tube.

The Characteristic of Two-Phase Flow Pattern on Air-Water Countercurrent Flow in Vertical Pipe

Two-phase flow is widely encountered in several engineering and industrial facilities. The purpose of this study is to investigate the characteristic of slug countercurrent flow pattern in a vertical small diameter pipe. An experimental investigation in this study has been performed toward a transparent tube of 19 mm diameter (outside diameter 22 mm, length 200 mm), water and air as the liquid and gas fluid in the vertical pipe followed by taking a picture of flow pattern in the transparent pipe using the high-speed camera. Two differential pressure sensors were set in transparent tube in order to receive slug countercurrent flow rate associated with the acquisition data as media to record data and then displayed on the screen. The two-phase flow was always preceded by the instability of flow rate and bubbles appearance. It occurred after the steady flow data acquisition rate was turned on for recording the differential pressure. The result showed that the flow pattern characteristic of two-phase flow (air-water) in the vertical pipe caused by the superficial velocity of air.

Cultivo de Arthrospira platensis (Spirulina) en fotobiorreactor tubular doblemente curvado a condiciones ambientales en el sur del Perú

<p><strong>Título en ingles: Cultivation of <em>Arthrospira platensis</em> (Spirulina) in curved</strong> <strong>doubly tubular photobioreactor to environmental conditions in the South of the Peru</strong><strong></strong><strong></strong></p><p><strong>Título corto: </strong><strong>Cultivo de <em>Arthrospira platensis </em>(Spirulina) en fotobiorreactor</strong></p><p><strong>Resumen: </strong>El presente trabajo investigó el cultivo de la microalga <em>Arthrospira platensis</em> (Spirulina) en valores de productividad cultivado en fotobiorreactor tubular doblemente curvado a condiciones ambientales con el fin de aprovechar la alta radiación solar de la región Arequipa en el sur de Perú (16°24´50´´ LS; 71°32´02´´ LO; 2344 msnm). El fotobiorreactor fue construido con un tubo transparente de policloruro de vinilo (PVC). La productividad del cultivo fue de 13.9 g/m² en 14 días ó 1 g/m²/día y una concentración de clorofila - “a” de 0.00785 mg/L con una máxima radiación de 1179 W/m², y una iluminación de 121500 lux, convirtiendo sus filamentos helicoidales a morfologías anormales, tales como formas irregulares curvas e incluso lineales con fragmentaciones, demostrando que el cultivo se vio afectado por la alta radiación y las variaciones de temperaturas de Arequipa.</p><p><strong>Palabras clave:</strong> cultivo, fotobiorreactor, productividad, sur de Perú, Spirulina.</p><p><strong>Abstract: </strong>The present work investigated the cultivation of microalgae <em>Arthrospira platensis</em> (Spirulina) in productivity values cultivated in doubly curved tubular photobioreactor to environmental conditions in order to take advantage of the high solar radiation of the Arequipa region in southern Peru (16°24´50´´ LS; 71°32´02´´LW; 2344 msnm.). The photobioreactor was built with a transparent tube of polyvinyl chloride (PVC). The productivity of the crop was 13.9 g/m² in 14 days or 1 g/m²/day and a concentration of chlorophyll - "a" 0.00785 mg/L with a maximum radiation of 1179 W/m², and a 121500 lux illumination, making its helical filaments abnormal morphologies, such as curves and linear even irregular shapes with fragmentation, demonstrating that the crop was affected by high radiation and variations in temperatures of Arequipa.</p><p><strong>Key words:</strong> culture, photobioreactor, productivity, South of Peru, Spirulina.</p><p><strong>Recibido:</strong> enero 22 de 2015<strong> Aprobado: </strong>abril 22 de 2015</p>

A Novel Design for a Cheap High Temperature Solar Collector: The Rotating Solar Boiler

In this work a novel type of high temperature solar collector is designed: the rotating solar boiler. This rotating solar boiler consists of two concentric tubes. The inner tube, called absorber, absorbs sunlight and boils water. The outer transparent tube, called cover, is filled with air. The boiler rotates to completely prevent convection in the insulating air layer in between the tubes. In this way, the heat loss is reduced considerably resulting in a solar collector that is more efficient than conventional flat plate solar collectors. The prototype built measured 1.20 m length and 0.50 m diameter (illuminated area is 0.60 m2) for the copper absorber with high performance sputtered coating. The cover with a diameter of 0.90 m was made of transparent polyvinylchloride film. The rotation speed was 60 rpm. The efficiency was 61% and the boiler delivered 0.34 kW of 100°C steam at an ambient temperature of 7°C. A model was developed to predict the performance of the prototype. The model predicts an efficiency of 62%, which is in agreement with the measured experimental efficiency. An economical analysis was performed as well. The rotating solar boiler is much cheaper than conventional evacuated tube collectors, especially because the rotating solar boiler is lightweight.

Fluid Transients in a Pipeline With One Open End

Water hammer during multi-phase flow is rather complex, but in some cases an upper limit to the pressure surge magnitude during water hammer can be estimated. In the case considered here, a two mile long pipeline with a single high point was permitted to partially drain. Due to gravitational effects, air bubbles up through the pipe line to its highest point, but the time required for air to reach the top of the pipe is rather long. Consequently, some transients caused by valve operations are affected by air entrapment and some are not. The intent of this research was to investigate the complex interactions between air, water vapor, and liquid during water hammer in a long pipe with one end of the pipe open to atmospheric conditions. To understand the system dynamics, experimental data was obtained from a long pipeline with an open end and also from a short, transparent tube. Transient calculations were performed for valve closures and pump operations as applicable. The limitations of available calculation techniques were considered in detail.