An insect’s eyes may make up to 40% of its body’s surface, and are in danger of being coated by foreign particles such as dust and pollen. To protect them, several insect species possess an array of ...ocular hairs evenly spaced between each photoreceptor unit. Although these hairs have been observed for over 50 years, their purpose remains a mystery. In this study, we elucidate the function of ocular hairs using a combination of experiments, numerical simulation and micro-fabrication. We measure the eyes of 18 species of insects and find that the length of their ocular hairs is equal to their spacing. We conduct wind tunnel experiments using both an insect eye mimic and an at-scale fabricated micro-pillar array of the same dimensions as the insect eye. Our experiments and simulations show that ocular hairs reduce airflow at the eye surface by up to 90%. We conclude that ocular hairs act similarly to mammalian eyelashes: as insects fly, ocular hairs deflect incoming air and create a zone of stagnant air. Airflow and particle deposition are reduced dramatically, while light is only minimally occluded. Micro-scale ocular hairs may find application in the deployment of sensors outdoors, for which accumulation of airborne dust and pollen has no current solution.
The results of studying the distributions of stable radiogenic and cosmogenic isotopes of noble gases in ordinary chondrites are reviewed here: the distributions of gas-retention and exposure ages ...are analyzed, the chronology and consequences of catastrophic destruction of the parent bodies of H and L chondrites are discussed, the fallen and preatmospheric masses of Antarctic and non-Antarctic meteorites are compared, the diffusion losses of noble gases in meteorites are considered, the ablation of meteorites and their mean lifetime after separation from the parent bodies are estimated, and a number of other problems are discussed.
Mirror alignment control for COMPASS RICH-1 detector Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2011, Letnik:
639, Številka:
1
Journal Article
Recenzirano
The focusing system of the COMPASS RICH-1 detector consists of two segmented spherical mirror surfaces, formed by 68 hexagonal and 48 pentagonal individual elements. All individual mirrors have two ...degrees of freedom to adjust the angular alignment in order to obtain a continuous spherical surface. Relative angular misalignments can be monitored on-line by the CLAM method, based on the optical reconstruction of line images. Complementing the CLAM measurements with photogrammetry, the absolute mirror orientation and position in space can be determined too. The method is described, as well as the algorithms used to access the relative and absolute mirror alignment.
Purpose of the study. To study the relationship between the gut microbiota composition, the state of the vascular wall and nutrient intake in patients without clinical manifestation of cardiovascular ...disease.Materials and methods. The study included 92 residents from Moscow and the Moscow region, men and women aged 25 to 76 y.o., without clinical manifestations of chronic diseases, with no medical treatment but with possible presence of cardiovascular risk factors. All the participants were examined with duplex scanning of the carotid arteries with the definition of the thickness of the intima-media complex (IMC), the presence of atherosclerotic plaques, measuring carotid-femoral pulse wave velocity (PWV), the measurement of interleukin-6 (IL-6) and C-reactive protein (C-RP) and sequencing of the V3-V4 variable regions of 16S rRNA genes of the gut microbiota.Diet was studied by quantitative assessment of consumer products using a standardized computer program «Analysis of Human Nutrition states» (version 1.2.4 Research Institute of Nutrition 2003-2006).Results. The study revealed that in the investigated cohort IMC thickness was greater in those with a large number of bacterial genera Serratia and Blautia. Bifidobacterium representation was increased and Blautia representation was decreased in those who consumed a lot of starch.Conclusion. The composition of the gut microbiota is associated with both vascular wall stiffness and atherosclerosis. In addition, the bacteria associated with subclinical atherosclerosis were more represented among those who consumed smaller amounts of complex carbohydrates.
When a swollen, thermoresponsive polymer gel is heated in a solvent bath, it expels solvent and deswells. When this heating is slow, deswelling proceeds homogeneously, as observed in a toroid-shaped ...gel that changes volume while maintaining its toroidal shape. By contrast, if the gel is heated quickly, an impermeable layer of collapsed polymer forms and traps solvent within the gel, arresting the volume change. The ensuing evolution of the gel then happens at fixed volume, leading to phase separation and the development of inhomogeneous stress that deforms the toroidal shape. We observe that this stress can cause the torus to buckle out of the plane, via a mechanism analogous to the bending of bimetallic strips upon heating. Our results demonstrate that thermodynamic instabilities, i.e., phase transitions, can be used to actuate mechanical deformation in an extreme thermodynamics of materials.
PDF
