121 research outputs found

    A Hierarchal Planning Framework for AUV Mission Management in a Spatio-Temporal Varying Ocean

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    The purpose of this paper is to provide a hierarchical dynamic mission planning framework for a single autonomous underwater vehicle (AUV) to accomplish task-assign process in a limited time interval while operating in an uncertain undersea environment, where spatio-temporal variability of the operating field is taken into account. To this end, a high level reactive mission planner and a low level motion planning system are constructed. The high level system is responsible for task priority assignment and guiding the vehicle toward a target of interest considering on-time termination of the mission. The lower layer is in charge of generating optimal trajectories based on sequence of tasks and dynamicity of operating terrain. The mission planner is able to reactively re-arrange the tasks based on mission/terrain updates while the low level planner is capable of coping unexpected changes of the terrain by correcting the old path and re-generating a new trajectory. As a result, the vehicle is able to undertake the maximum number of tasks with certain degree of maneuverability having situational awareness of the operating field. The computational engine of the mentioned framework is based on the biogeography based optimization (BBO) algorithm that is capable of providing efficient solutions. To evaluate the performance of the proposed framework, firstly, a realistic model of undersea environment is provided based on realistic map data, and then several scenarios, treated as real experiments, are designed through the simulation study. Additionally, to show the robustness and reliability of the framework, Monte-Carlo simulation is carried out and statistical analysis is performed. The results of simulations indicate the significant potential of the two-level hierarchical mission planning system in mission success and its applicability for real-time implementation

    Electrical and Optical Properties of Flexible Transparent Silver Nanowires electrodes

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    AgNWs were produced by the one-pot polyol method, and it had been produced by reduction of AgNO3 by ethylene glycol in presence of polyvinylpyrrolidone (PVP) and KCl at high temperature of about 160 oC. AgNWs suspension were purified by centrifuging at 3000 rpm for three times then re-depressed in deionized water with a concentration of 1%. The purified suspension was diluted to different concentrations (2-5) mg. mL-1 using 1% of hydroxy methylcellulose to design different AgNWs transparent conductive films (AgNWs-TCFs). AgNWs suspension inks were coated on the glass and polyethylene terephthalate (PET) substrates. Different AgNWs diameters were obtained by changing the synthesis conditions. It has been observed that the wire diameter will greatly affect both the optical and electrical properties of the obtained AgNWs-TCFs. The best obtained AgNWs-TCFs had high transparency of about 91.5 %, small sheet resistance of about 14 .03 Ω and optical haze less than 2%, which met the requirements for the manufacture of optoelectronic and sensor equipment. Keywords: Silver nanowires, transparent conductive electrode, flexible electrodes, polyol method, AgNWs size control, AgNWs size-dependent and one-pot synthesis

    A conditionally immortalized cell line from murine proximal tubule

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    A conditionally immortalized cell line from murine proximal tubule. We have developed a conditionally immortalized murine cell line with proximal tubule characteristics (tsMPT) and a background suitable for genetic manipulations. tsMPT was derived from the F1 progeny of crosses between: [1] a transgenic mouse harboring a γ-interferon (IFN-γ)-inducible, temperature sensitive SV40 large T antigen gene (tsA58) and [2] mice of the 129/SvEv strain, the background from which most embryonic stem (ES) cells are derived. Under permissive conditions (33°C and in the presence of IFN-γ), tsMPT cells grow rapidly as monolayers with a doubling time of 23 hours; the large T antigen can be detected by immunocytochemistry and by Western blotting. When transferred to non-permissive conditions (39°C, without IFN-γ), the cells undergo differentiation coinciding with the disappearance of the large T antigen. By electron microscopy, tsMPT cells are polarized and show microvilli at their apical surface. tsMPT cells express brush border enzymes γ-glutamyl transpeptidase and carbonic anhydrase IV. They possess Na+-dependent transport systems for Pi, D-glucose and L-proline as well as an amiloride-insensitive Na+-H+ exchanger. Intracellular cAMP generation is stimulated by parathyroid hormone but not by arginine vasopressin. Angiotensinogen mRNA and protein are present in tsMPT with markedly higher levels at non-permissive conditions. tsMPT cells should be a useful model for investigation of the functional features of the proximal tubule epithelium in relation to cellular differentiation

    CHEMICAL CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF JORDANIAN PROPOLIS AND NIGELLA SATIVA SEED OIL AGAINST CLINICALLY ISOLATED MICROORGANISMS

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    Objective: Increasing use of medicinal plants in the treatment of infectious diseases are due to the development of multi-antibiotics resistant microorganisms, and had alerted our interest in the examination of some natural products. This study was carried out to investigate the antimicrobial activity of Jordanian propolis, black seed oil (Nigella sativa) extract, alone or in combination against clinically isolated microorganisms (bacteria and fungi).Methods: Jordanian propolis samples were collected. Aqueous and alcoholic extractions were done; black seed oil was extracted from Nigella sativa seeds. Seven clinical isolated microorganisms namely: Micrococcus luteus, Bacillus pumilus, Bordetella bronchisptica, Enterococcus fecalis, Bacillus subtilis, and Staphylococcus aureus, and one yeast strain namely Candida albicans were used. The antimicrobial activity was investigated by agar diffusion technique and microplate dilution to determine the MIC.Results: The results indicated that the alcoholic propolis extract showed higher antimicrobial activity than the aqueous propolis extract. The antimicrobial activity of black seed oil was significantly higher than that of the propolis. Mixing propolis with black seed oil showed synergism effects against some microorganisms as Enterococcus fecalis (24±1.1), Bordetella bronchisptica (20±0.9) and Candida albicans (40±2.3), and additive with others as Bacillus subtilis (28±1.8).Conclusion: Black seed oil and propolis might be used as a potential source of safe and effective natural antimicrobial in pharmaceutical and food industries

    Enhanced thermal performance of closed-cell rigid Polyurethane (PU) foam panels using phase change materials (PCMs)

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    The consequences of extreme energy consumption are seen both in the energy and environmental crisis. Subsequently, researchers are attempting to find methods to address this issue. Building envelopes and insulation materials are elements that can effectively influence consumption through their passive effect on thermal comfort levels. Strategies pertaining to this that rely on both, advanced and traditional materials, have been able to show good potential. However, the technical complexity of using such strategies can be impeded from the perspective of developing countries. With the aim of creating effective low-cost feasible insulations through using methods of minimal intricacies, the potentials of simple amalgamation of materials are empirically investigated in this study. In this context, closed-cell rigid Polyurethane (PU) foam is used as a base to hold phase change materials (PCMs) to create two PU/PCM panels, of different PCM content. The thermal performance of the panels is experimentally examined and compared, with hot-arid climates prevailing in developing countries in mind. Results revealed that panels containing PCMs were able to perform more effectively in comparison with regular PU foam panels, and, that increasing the amount of PCM has also shown to be advantageous in this regard

    Influence of Phase Change Materials (PCMs) on Polyurethane (PU) Foam Fire-Retardancy

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    Polyurethane (PU) foam is a material that has long been regarded as a good thermal insulator for building purposes due to many advantageous attributes, such as cost and feasibility. Yet, to further develop its performance, many studies have focused on the potential of using the micro-structure of PU foam as an encapsulation for PCMs. Despite the apparent advantageous outcome of this premise, from the perspective of thermal performance, fire-retardancy issues may pose as a threat. PU foam is known for its inherent poor fire-retardation properties. With the addition of PCMs, especially wax-based, it is possible that the fire-retardancy would worsen. This would translate into additional costs in terms of application of treatments to counter the disadvantageous hazardous properties. In this study, an empirical investigation is carried out with the aim of determining whether addition PCMs to PU foam would influence its retardation, and to which extent. In this context, granules of wax-based PCMs are encapsulated in to closed-cell rigid PU foam via a simplified amalgamation method. Two concentrations of PCM content are presented in this paper. Then, fire-retardancy testing is performed on specimens to compare the performance of the created PU/PCM specimens with this of regular PU specimens. The outcome of this empirical investigation further confirms that addition of PCM to PU foam is disadvantageous in terms of fire-retardancy, and that the amount of added PCM is of considerable influence on this

    Oral Focal Mucinosis: A case report

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    Oral focal mucinosis is a rare lesion with less than 60 cases reported in English literature so far, to the best of our knowledge. It is considered to be the oral counterpart of cutaneous focal mucinosis and/or cutaneous myxoid cyst. Histopathologically, Oral focal mucinosis is demonsterates a well-circumscribed area of myxomatous connective tissue containing mucinous material, surrounded by denser collagenous connective tissue. We present a case of Oral focal mucinosis occurring on the buccal gingiva of the lower jaw

    An improved indoor positioning based on crowd-sensing data fusion and particle filter

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    Due to the lack of global positioning system (GPS) signals in some enclosed areas, indoor localization has recently gained significant importance for academics. However, indoor localization has a number of challenges and defects, including accuracy, cost, coverage, and ease of use. This paper explores the integration between the inertial measurement unit (IMU) and Wi-Fi-based received signal strength indicator (RSSI) measurements, demonstrating their combined potential for robust indoor localization. IMUs excel at capturing precise short-term motion dynamics, offering insights into an object’s acceleration and orientation. Conversely, RSSI measurements serve as valuable indicators for relative positioning within indoor environments. By fusing data from these sources, our approach compensates for the inherent weaknesses of each sensor type. To achieve accurate indoor positioning, we employ techniques such as sensor fusion, Wi-Fi fingerprinting, and dead reckoning. Wi-Fi fingerprinting allows us to create a database that maps RSSI measurements to specific locations, while dead reckoning helps mitigate drift and inaccuracies. By combining these methods, we estimate a device’s position with increased precision. Through experimental evaluation, we assess the performance and efficiency of our integrated approach, comparing the estimated path or new location with a predefined reference path. The findings emphasise a significant improvement in accuracy, with the integration of crowd-sensing, particle filtering, and magnetic fingerprinting techniques resulting in a notable increase from 80.49% to 96.32% accuracy

    Association of Follicular Fluid Antioxidants Activity with Aging and In Vitro Fertilization Outcome: A Cross-Sectional Study

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    Background: This research was aimed at assessing the relationship between the follicular fluid (FF) antioxidantsactivity, aging and in vitro fertilization (IVF) outcome.Materials and Methods: The present cross-sectional study was carried out on 65 women undergoing IVF/intracytoplasmicsperm injection (IVF/ICSI) cycles due to unexplained infertility. Ovarian stimulation was performed using thelong gonadotropin-releasing hormone (GnRH) agonist protocol. After ovum pickup, FF was collected and processedto measure the level of superoxide dismutase (SOD), catalase (CAT) activity, total antioxidant capacity (TAC) andglutathione (GSH). Day 3 after ICSI, fresh embryos were transferred and later, possible pregnancy was assessed.Patients participating in this study were divided into four groups on the basis of age and pregnancy outcome.Results: SOD activity was not significantly different between the groups (P=0.218). GSH in the group whose participantswere aged ≤35 years and were pregnant was higher than that in other groups. CAT activity in groups withyounger participants was higher compared to the other groups. The mean TAC was higher in groups with pregnantparticipants compared to the non-pregnant women. Correlation analysis showed that: GSH level had a significantnegative correlation with age (P<0.001, R -0.55) and a significant positive correlation with pregnancy (P=0.015,R=0.30). CAT level also had a significant negative correlation with age (P<0.001, R=-0.42) and the level of TAC hada significant positive correlation with pregnancy (P<0.001, R=0.59).Conclusion: According to our results, the levels of TAC, GSH and CAT in younger and pregnant women were highercompared with those undergoing ICSI cycles. Given the correlation of FF antioxidant activity with age and pregnancy,it is necessary to carry out more research on these compounds and the maintenance of pregnancy
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