Tubular adsorption reactors have been used in solar cooling systems since 1983. The original design consisted in a metal screen tube concentrically inserted into a copper tube;granules of solid adsorbent are packed in...
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ISBN:
(纸本)9782362150128
Tubular adsorption reactors have been used in solar cooling systems since 1983. The original design consisted in a metal screen tube concentrically inserted into a copper tube;granules of solid adsorbent are packed in the space between the two tubes. Two experimental setups were used to measure the degree of contribution provided by radial adsorbate flow through the metal screen on adsorption kinetics: the first setup was composed by a tube fully filled with adsorbent, resulting in mainly axial adsorbate flow, while the second one was composed by an external tube with an internal, coaxial metal mesh tube leading to free adsorbent flow lengthwise, resulting in predominant radial flow through the adsorbent bed. The adsorption working pair was constituted by silica gel and water. This particular pair is preferred for adsorption chillers due to its superior thermodynamic characteristics. Temperature and mass measurements were made along the adsorption process to compare the heat and mass transfers obtained with each reactor configuration.
This paper presents a computational system to perform, simultaneously, the control of th 3D position and trajectory of two commercial unmanned aerial vehicles (UAVs), the Parrot AR. Drone quad copter. The developed sy...
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Background: Experimental and epidemiological studies indicate an association between exposure to particulate matter (PM) air pollution and increased risk of type 2 diabetes. In view of the high and increasing prevalen...
Background: Experimental and epidemiological studies indicate an association between exposure to particulate matter (PM) air pollution and increased risk of type 2 diabetes. In view of the high and increasing prevalence of diabetes, we aimed to quantify the burden of type 2 diabetes attributable to PM2·5 originating from ambient and household air pollution. Methods: We systematically compiled all relevant cohort and case-control studies assessing the effect of exposure to household and ambient fine particulate matter (PM2·5) air pollution on type 2 diabetes incidence and mortality. We derived an exposure–response curve from the extracted relative risk estimates using the MR-BRT (meta-regression—Bayesian, regularised, trimmed) tool. The estimated curve was linked to ambient and household PM2·5 exposures from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, and estimates of the attributable burden (population attributable fractions and rates per 100 000 population of deaths and disability-adjusted life-years) for 204 countries from 1990 to 2019 were calculated. We also assessed the role of changes in exposure, population size, age, and type 2 diabetes incidence in the observed trend in PM2·5-attributable type 2 diabetes burden. All estimates are presented with 95% uncertainty intervals. Findings: In 2019, approximately a fifth of the global burden of type 2 diabetes was attributable to PM2·5 exposure, with an estimated 3·78 (95% uncertainty interval 2·68–4·83) deaths per 100 000 population and 167 (117–223) disability-adjusted life-years (DALYs) per 100 000 population. Approximately 13·4% (9·49–17·5) of deaths and 13·6% (9·73–17·9) of DALYs due to type 2 diabetes were contributed by ambient PM2·5, and 6·50% (4·22–9·53) of deaths and 5·92% (3·81–8·64) of DALYs by household air pollution. High burdens, in terms of numbers as well as rates, were estimated in Asia, sub-Saharan Africa, and South Am
The present paper focuses on the effect of air jets through a perforated thin plate on the characteristics of an acoustic absorption coefficient. We measured the flow rate, internal pressure, acoustic pressure, and tr...
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The present paper focuses on the effect of air jets through a perforated thin plate on the characteristics of an acoustic absorption coefficient. We measured the flow rate, internal pressure, acoustic pressure, and transfer function by using an improved acoustic impedance tube. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. As a result, the frequency characteristics of the acoustic absorption coefficient against the frequency showed a maximum value at the local frequency. The peak frequency of the acoustic absorption coefficient depended on the thickness of the background air space and the thickness of the perforated plate. As the flow rate increased through the micropores, the peak level of the acoustic absorption coefficient also increased until a flow rate of 80?l /min. As the flow rate further increased, the peak level of the acoustic absorption coefficient decreased and that of the high frequency band increased.
This paper presents a robotic gait training system for neuro-motor rehabilitation of hemiplegic stroke survivors. The system is composed of a treadmill consisting of two separated belts, footprint array sensor attache...
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ISBN:
(纸本)9781424492695
This paper presents a robotic gait training system for neuro-motor rehabilitation of hemiplegic stroke survivors. The system is composed of a treadmill consisting of two separated belts, footprint array sensor attached below each belt for gait data acquisition, and an electroencephalography (EEG) device for monitoring brain activities during gait training. The split belt treadmill allow physical therapists to set different treadmill belt velocities to modify physical workload of the patients during walking, thus being able to better improve the symmetry of gait phases between affected and unaffected (sound) legs in comparison with conventional treadmills where there is only one single belt. In contrast to in-shoe pressure sensors, the under-belt footprint sensor array designed in this study not only reduces the preparation complexity of gait training but also collects more gait data for motion analysis. Recorded EEG is segmented synchronously with gait-related events. The processed EEG data can be used for monitoring brain-activities during gait training, providing a neurological approach for motion assessment. One subject with simulated stroke using an ankle-foot orthosis participated in this study. Preliminary results indicate the feasibility of the proposed system to improve gait function and monitor neuro-motor recovery.
In this paper, a new kind of swarm-based metaheuristic search method, called Elephant Herding Optimization (EHO), is proposed for solving optimization tasks. The EHO method is inspired by the herding behavior of eleph...
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In this paper, a new kind of swarm-based metaheuristic search method, called Elephant Herding Optimization (EHO), is proposed for solving optimization tasks. The EHO method is inspired by the herding behavior of elephant group. In nature, the elephants belonging to different clans live together under the leadership of a matriarch, and the male elephants will leave their family group when they grow up. These two behaviors can be modelled into two following operators: clan updating operator and separating operator. In EHO, the elephants in each clan are updated by its current position and matriarch through clan updating operator. It is followed by the implementation of the separating operator which can enhance the population diversity at the later search phase. To demonstrate its effectiveness, EHO is benchmarked by fifteen test cases comparing with BBO, DE and GA. The results show that EHO can find the better values on most benchmark problems than those three metaheuristic algorithms.
We developed a search-and-rescue robot to locate people in buildings following an earthquake disaster. In such an environment, there may be obstacles such as slopes, stairs, and rubble;however, with remote control sys...
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ISBN:
(纸本)9781467396769
We developed a search-and-rescue robot to locate people in buildings following an earthquake disaster. In such an environment, there may be obstacles such as slopes, stairs, and rubble;however, with remote control systems, there can be a delay in obtaining an image, due to the wireless communications system, which makes maneuvering the robot challenging. In particular, it can be difficult to climb slopes and stairs. Here, we use an acceleration sensor to automate the negotiation of slopes and stairs and describe the experimental results of this approach.
According to the automobile industry's flexible manufacturing requirements, a novel flexible fixturing system for sheet metal assembly is proposed with parallel robots. A methodology of the structure synthesis is ...
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According to the automobile industry's flexible manufacturing requirements, a novel flexible fixturing system for sheet metal assembly is proposed with parallel robots. A methodology of the structure synthesis is presented by taking account simultaneously several performance indices. Taking the 3UPU/UPS parallel robot in the system as an example, models of inverse kinematics, Jacobian matrix and design space are developed. Thus, the structure synthesis of the parallel robot is simplified to a two-dimensional problem. Once the performance indices (workspace, singularity and stiffness) are established, the corresponding indices atlases are expressed in the design space. The structure parameters of the parallel robot are obtained by analyzing these atlases. The prototype of the fixturing system is developed, and the relevant clamping and stiffness experiments are conducted. The experimental results generally agree well with the simulation results and satisfy the flexible fixturing systems' requirements.
Over the past decades, dramatic increases in population and quality of life have led to an ever-growing need for wastewater infrastructure systems. Designing and applying novel pipelines with lower installation and lo...
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Over the past decades, dramatic increases in population and quality of life have led to an ever-growing need for wastewater infrastructure systems. Designing and applying novel pipelines with lower installation and long-term operation and maintenance expense will become crucial in the near future for the implementation of the best environmental management strategies. In this paper, a comparative life cycle analysis (LCA) was performed for four different types of wastewater pipe materials: composite fiber reinforced Polymer (FRP), PVC, ductile iron, and concrete. The functional unit in our analysis was defined as the infrastructure needed for the collection and transportation of one cubic meter of waste water from a city for a period of 50 years. Assuming a city that has a population of 200,000 and generates 0.3 cubic meter of wastewater per person per day, the reference flow for the above assumed functional unit can be deduced. Considering various life cycle stages, environmental impacts such as “ozone layer depletion”, eco-toxicity”, and “energy consumption” were quantified and compared for all pipe materials. The results show the production phase has the maximum impact among the different phases of all pipe manufacturing and within different environmental impacts; fossil fuel is the largely affected area in all piping systems and among the four pipes, ductile iron has the maximum impact and PVC has the minimum impact on most of these areas.
The prototyping of products by additive and subtractive technology can vary in: quality, time and costs, depending on the characteristics of the products. The selection of technology often is conditioned the decision ...
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