To identify the physical effects, behavioral changes, and gene expression profiles of the phase 1 detoxification-related gene (cyp 1a) and oogenesis-related gene (vtg 1) induced by microplastics, ...high-density polyethylene microplastics of various sizes were used because of their dominance in coastal areas and effluent samples in Hong Kong. Adult zebrafish were used as the model organism to identify the upper and lower boundaries of microplastics ingestion and were exposed to individual polyethylene microplastics in five size ranges (10–22 μm, 45–53 μm, 90–106 μm, 212–250 μm, and 500–600 μm) at a concentration of 2 mg/L for 96 h. To study behavioral changes and targeted gene expression profiles via real-time PCR (qPCR), a mixture of microplastics in three size ranges at effluent-related (11 particles/L), moderate (110 particles/L), and high concentrations (1,100 particles/L) were applied for 96 h. The zebrafish behavior was recorded by a video camera and by two observers (interrater reliability, >85%). The results implied that the upper and lower size boundaries for microplastic ingestion were 558.4 ± 26.2 μm (yellow) and 19.7 ± 3.1 μm (red), respectively. In addition, 61 ± 10% of fish in medium concentration treatments and 61 ± 10% of fish in high concentration treatments were found with the microplastic ingestion and remaining in their intestine. In addition, 28 ± 10% of fish in high concentration treatments were found with microplastic retaining in their gills (No. of fishes = 18 in each treatment). The presence of microplastics, which occupied 89 ± 6% of intestine area, reduced the voids inside the intestine for feed. The expression of cyp1a in the intestine (medium concentration) and vtg1 in the liver (medium and high concentration) showed significant up-regulation, and abnormal behavior (i.e., seizures and tail bent downward) was observed (medium and high concentration). In summary, the effects on the aryl hydrocarbon receptor (AHR) pathway, disruption of the oogenesis process, and neurotoxicity could be caused by acute exposure of adult zebrafish to microplastics.
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•Different sizes of polyethylene (PE) pellets were exposed to adult zebrafish.•Behavioral changes were noticed in fish exposed to PE.•Level of cyp1a in the intestine (medium concentration) showed up-regulation.•Level of vtg1 in the liver (medium and high concentration) also showed up-regulation.
•A framework of a ubiquitous thermal comfort assessment for energy-efficient HVAC.•The framework infers human thermoregulation states using RGB video images.•The framework draws on thermoregulation ...mechanisms and Eulerian video magnification.•Subtle blood flow variations to facial skin due to thermoregulation are inferred.•The feasibility was evaluated for 21 participants under low and high temperatures.
HVAC systems account for more than 40% of energy consumption in buildings to provide satisfactory indoor environments for occupants. The integration of personalized thermal comfort in the operation of HVAC systems has been shown to be highly effective in enhancing energy efficiency of buildings. To this end, research efforts have proposed personalized thermal comfort assessment through voting (i.e., occupant feedback) and profiling as well as physiological response measurement. In this study, we have proposed a novel approach for enabling RGB video cameras as sensors for measuring personalized thermoregulation states – an indicator of thermal comfort. If their feasibility for thermoregulation state inference could be established, optical cameras provide a cost-effective and omnipresent solution for distributed measurement of thermal comfort and consequently control of HVAC systems for energy saving. Accordingly, we have proposed a framework that draws on the concepts of thermoregulation mechanisms in the human body as well as the Eulerian video magnification approach. The framework is composed of several components including face detection, skin pixels isolation, image magnification. And calculation of detection index to infer subtle blood flow variations to the facial skin surface (i.e., blood perfusion), which is due to thermoregulation adjustments. In order to minimize the impact of variable illumination condition and the ambient noise on the results, different combinations of methods for framework components were taken into account. The feasibility assessments were conducted through an experimental study with 21 participants under low (20 °C) and high (30 °C) temperatures. In total, 16 positive cases out of 18 statistically significant cases were observed resulting in 89% of success rate using the most promising combinations of the methods. The results demonstrate that the proposed framework could contribute to realization of a non-intrusive, cost-effective, and ubiquitous distributed thermal comfort assessment that has been proven critical in increasing energy efficiency of the HVAC system through distributed control feedback.
•An increased level of turbulence around ramps is the result of different manoeuvres.•Turbulence is mainly characterised by an increased number of lane changes.•Most lane changes are performed by ...merging and diverging drivers.•The effects of discretionary lane changes, cooperation and relaxation are mild.
In the vicinity of ramps, drivers make route choices, change lanes and in most cases also adjust their speeds. This can trigger anticipatory behaviour by the surrounding vehicles, which are also reflected in lane changes and/or changes in speed. This phenomenon is called turbulence and is widely recognised by the scientific literature and various design guidelines. However the knowledge about the characteristics of turbulence is limited. This study investigates the microscopic characteristics of driving behaviour around 14 different on-ramps (3), off-ramps (3) and weaving segments (8) in The Netherlands, based on unique empirical trajectory data collected from a video camera mounted underneath a hovering helicopter. The data analysis reveals that lane changes caused by merging and diverging vehicles create most turbulence, that an increase in the amount of traffic results in a higher level of turbulence and that an increase in the available length for merging and diverging results in a lower level of turbulence. The results of this study are useful for improving the road design guidelines and for modelling driving behaviour more realistically.
Micro Direct methanol fuel cell (μDMFC) has attracted wide attention in the field of portable electronic equipment because of its unique advantages such as no charge, environment friendliness, simple ...structure and convenient fuel storage. It has obtained important applications in laptop, mobile phones, micro-satellites, electric vehicles, MEMS devices, video camera and other aspects. So, it is significant to study in depth its structure, functional characteristics and applications. This review shows the progress on the recent development of micro direct methanol fuel cell. Lots of functional components including micro flow field plate, membrane electrode assembly, proton exchange membrane, catalytic layer, diffusion layer and collector are studied and discussed. The supplies management and packaging technology are also explained and discussed in detail. A mass of portable devices whose power are supplied by μDMFC are researched and discussed. This work will provide an comprehensive guide to those who want to study μDMFC.
Benthic community succession patterns at whale falls have been previously established by means of punctual submersible and ROV observations. The contribution of faunal activity rhythms in response to ...internal tides and photoperiod cues to that community succession dynamism has never been evaluated. Here, we present results from a high-frequency monitoring experiment of an implanted sperm whale carcass in the continental slope (500 m depth) offshore Sagami Bay, Japan. The benthic community succession was monitored at a high frequency in a prolonged fashion (i.e. 2-h intervals for 2.5 months) with a seafloor lander equipped with a time-lapse video camera and an acoustic Doppler profiler to concomitantly study current flow dynamics. We reported here for the first time, to the best of our knowledge, the occurrence of strong 24-h day-night driven behavioral rhythms of the most abundant species (Simenchelys parasitica; Macrocheira kaempferi, and Pterothrissus gissu). Those rhythms were detected in detriment of tidally-controlled ones. Evidence of a diel temporal niche portioning between scavengers and predators avoiding co-occurrence at the carcass, is also provided. The high-frequency photographic and oceanographic data acquisition also helped to precisely discriminate the transition timing between the successional stages previously described for whale falls' attendant communities.
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•Classification of a binary mixture of two different particle sizes and densities.•Two relatively pure layers formed as the end result of the segregation process.•A good qualitative ...agreement between the experiments and the simulation results.•CPFD modelling can be useful to design and analyze fluidized bed classification.
The main objectives of this study were to quantify the classification efficiency of a binary mixture of two different particle types and to demonstrate that CPFD can be used to simulate the main features of the classification process. A lab-scale cylindrical fluidized bed (8.4 cm inner diameter, 150 cm height), equipped with pressure sensors and a video camera for recordings, was applied in the experiments. The particles used in the study were ceramic beads (median diameter 70 µm, skeletal density 3830 kg/m3) and steel shot (290 µm, 7790 kg/m3). Ambient air was used as the fluidization medium.
The minimum fluidization velocities of pure ceramic beads and steel shot were found to be 0.015 m/s and 0.240 m/s, respectively. In the experiments with a binary mixture of the two materials, the fluidization column was filled by alternating layers of ceramic beads and steel shot. In principle, segregation of the two particle types can be obtained by applying a suitable gas velocity within the interval defined by the two minimum fluidization velocities, resulting in a top layer of mainly lighter and smaller particles (flotsam) and a bottom layer of mainly heavier and larger particles (jetsam). In the experiments, the air velocity was gradually increased until the entire bed was fluidized. A gradual rearrangement of the multi-layer structure into a two-layer structure was observed. The rearrangement started at the top and then progressed downwards until most of the steel particles were collected at the bottom of the bed and practically all the ceramic beads were gathered at the top. The velocity at which the flotsam and jetsam layers were clearly segregated was found to be 0.180 m/s. The jetsam layer contained less than 0.3 wt% ceramic beads indicating that an almost pure steel shot fraction could be produced through fluidized bed classification. The flotsam layer was, however, less pure, with a steel shot content up to 24 wt%, suggesting that this layer may need a second classification stage for improved purity.
Computational particle-fluid dynamics (CPFD) simulations of the same setup were performed using the commercial software Barracuda. The simulated minimum fluidization velocity of steel shot, applying the Ergun drag model, perfectly matched the experimental value. For the ceramic beads, however, the simulations, applying the Wen-Yu drag model, gave a value lower than the experimental value. Still, the simulations were able to capture the general behavior of the particles in the bed observed in the classification experiments, i.e. the rearrangement of the layers, even if a higher gas velocity was required for complete classification of the particles. The formation of air pockets was also observed in the simulations, as in some of the experiments. The results suggest that Barracuda CPFD simulations can be a useful tool in design and evaluation of fluidized bed classifiers.
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The wetting behavior of an electrolyte solution on the separator, determined by contact-angle measurements, has a significant effect on the internal resistance of the battery and on ...its cycle life. The solvent, the lithium-salt type and its concentration may affect the wettability. However, few systematic studies address the effect of salt concentration on surface tension and contact angle.
Surface tensions and advancing contact angles were measured for dimethyl sulfoxide (DMSO), propylene carbonate (PC), dimethyl carbonate (DMC), and a PC/DMC mixture (1:1 mass ratio) with various concentrations of a lithium salt (LiClO4, LiPF6, and LiTFSI) at 23 °C. Measurements were made by a Krüss Drop Shape Analyzer 100, with a video camera mounted on a microscope to record the drop image.
For DMSO, PC and PC/DMC, surface tensions increase by adding LiClO4 or LiPF6 but decrease upon addition of LiTFSI. For DMC, the lithium salts have little impact on the surface tensions. For each solvent, contact angles and adhesion energies follow the same trend as those for surface tensions. The TFSI- anion reduces the surface tension of the solvent, favoring good wettability of the separator. The optimal surface tension for wettability of Celgard 2500 is at or below 26.1 mN/m.
•Bubble formation between μm and mm orifices are different under low gas flow rate.•Under high gas flow rate, coalescence bubbling regimes are observed at μm orifices.•The CFD can simulate the ...dynamic characteristics of bubbles at μm orifices well.
Visualization experiments and numerical simulations were carried out to investigate the bubble dynamic behavior at the submerged micron orifice. The diameters of the orifices varied from 0.136mm to 0.204mm. The bubble formation process was recorded by a high-speed video camera. The detailed bubble characteristics were obtained through image processing and a following Matlab analysis. The outcomes indicate that under a low gas flow rate, the bubble grows and detaches individually, and the bubble formation progress can be differentiated into three stages: nucleation, stable growth, and necking. The differences between micron and millimeter level orifices are obvious at the initial level of bubble formation. At the micron level, the bubble is strongly influenced by capillary pressure and it causes a longer waiting time. It is also found that the bubble shape only depends on the instantaneous bubble volume and has no relation with the gas flow under a high flow rate. We observed that the coalescence bubbling regimes are different from the multi-period formation mechanism at the millimeter level. The final bubble volume demonstrates an index increasing law with the gas flow rate. Additionally, the volume-of-fluid method was used for numerical simulation of the bubble formation process. It indicates that numerical simulations can finely predict the dynamic features of bubbles against the experiments, under low gas flow rate conditions (0.95–4.83ml/min).
•Phenomenon of heterogeneous droplet breakup has been found when heating.•Time of heating until an explosive disintegration has been determined.•Impact of gas temperature and inclusion sizes on ...droplet heating has been measured.•Conditions for intensive vaporization at solid/liquid interface have been stated.•Spherical, disk, parallelepiped and polyhedron inclusions have been considered.
Experimental investigation of evaporation and boiling was carried out on fixed water droplet containing a single nontransparent solid inclusion and placed in gaseous environment at high-temperature (500–1100K). We carried out experiments with water droplets (diameters 3–5mm) containing graphite inclusions of different shapes (sphere, disk, cone, parallelepiped and polyhedron) with sizes between 2 and 4mm. These droplets were in the hot flux on top of combustion of industrial ethanol. The behavior of the droplets was recorded by high-speed (up to 105 frames per second) video cameras “Phantom” and “TEMA Automotive” software. Conditions for intensive vaporization at solid/liquid interface inside droplets were determined. A phenomenon of explosive disintegration occurred when heating some of the heterogeneous droplets. Time of heating until an explosive disintegration and complete evaporation was recorded. Influence of gas temperature and inclusion sizes were measured.
•An intelligent fire detection approach through cameras based on computer vision methods is proposed.•A motion detection method based on background subtraction is used for reducing computations.•An ...object detection model and an image classification model are constructed and applied for fire detection.•The fire detection rate achieves 98.4% and the false alarm rate achieves 99.9% based on the fire image dataset.•The detection time for one frame achieves 27.4 ms.
Fire that is one of the most serious accidents in petroleum and chemical factories, may lead to considerable production losses, equipment damages and casualties. Traditional fire detection was done by operators through video cameras in petroleum and chemical facilities. However, it is an unrealistic job for the operator in a large chemical facility to find out the fire in time because there may be hundreds of video cameras installed and the operator may have multiple tasks during his/her shift. With the rapid development of computer vision, intelligent fire detection has received extensive attention from academia and industry. In this paper, we present a novel intelligent fire detection approach through video cameras for preventing fire hazards from going out of control in chemical factories and other high-fire-risk industries. The approach includes three steps: motion detection, fire detection and region classification. At first, moving objects are detected through cameras by a background subtraction method. Then the frame with moving objects is determined by a fire detection model which can output fire regions and their locations. Since false fire regions (some objects similar with fire) may be generated, a region classification model is used to identify whether it is a fire region or not. Once fire appears in any camera, the approach can detect it and output the coordinates of the fire region. Simultaneously, instant messages will be immediately sent to safety supervisors as a fire alarm. The approach can meet the needs of real-time fire detection on the precision and the speed. Its industrial deployment will help detect fire at the very early stage, facilitate the emergency management and therefore significantly contribute to loss prevention.
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