95 research outputs found

    Generator voltage stabilisation for series-hybrid electric vehicles

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    This paper presents a controller for use in speed control of an internal combustion engine for series-hybrid electric vehicle applications. Particular reference is made to the stability of the rectified DC link voltage under load disturbance. In the system under consideration, the primary power source is a four-cylinder normally aspirated gasoline internal combustion engine, which is mechanically coupled to a three-phase permanent magnet AC generator. The generated AC voltage is subsequently rectified to supply a lead-acid battery, and permanent magnet traction motors via three-phase full bridge power electronic inverters. Two complementary performance objectives exist. Firstly to maintain the internal combustion engine at its optimal operating point, and secondly to supply a stable 42 V supply to the traction drive inverters. Achievement of these goals minimises the transient energy storage requirements at the DC link, with a consequent reduction in both weight and cost. These objectives imply constant velocity operation of the internal combustion engine under external load disturbances and changes in both operating conditions and vehicle speed set-points. An electronically operated throttle allows closed loop engine velocity control. System time delays and nonlinearities render closed loop control design extremely problematic. A model-based controller is designed and shown to be effective in controlling the DC link voltage, resulting in the well-conditioned operation of the hybrid vehicle

    Production Ratios of Strange Baryons from QGP with Diquarks

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    Assuming that vector and scalar diquarks exist in the Quark-Gluon Plasma near the critical temporature TcT_c, baryons can be produced through the processes of quarks and diquarks forming (1/2)+({1/2})^+ baryon states. Ratios of different baryons can be estimated through this method, if such kind of QGP with diquarks can exists.Comment: Correct some expressions of equation

    Comparison of artifacts between paste and collodion method of electrode application in pediatric EEG

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    © 2019 International Federation of Clinical Neurophysiology Objectives: Children pose challenges to obtain quality EEG data due to excessive artifact. Collodion is used in EEG electrodes due to its water resistance and strong adhesive qualities. This study was done to evaluate differences in artifacts between the collodion and paste method. Methods: 115 subjects (children age \u3e3 years) were randomized into paste and collodion groups and artifacts evaluated at baseline and every hour over 30 s increments. Age, sleep state, and number of electrodes with artifact were also documented. T-test was performed to determine differences in the various parameters between the two groups. Results: 61 subjects were in the paste group and 54 in the collodion group. Mean of total seconds of artifact from 0 to 24 h were 41.8 s in paste group versus 30.3 s in collodion group (P = 0.02). Children \u3e11 years old had less artifact than younger children from 0 to 24 h (24.3 versus 41.2 s, P = 0.03), and from 24 to 48 h (33.1 versus 43.1 s, P = 0.03). There was a significant effect of sleep vs. awake state recordings on artifact from 0 to 24 h (30.3 versus 50.2 s, P = 0.01). Conclusion: Electrode problems are common with both collodion and paste in prolonged AEEG monitoring. However, for studies less than 24 h, collodion may be a better alternative. Significance: Our study provides evidence that in some cases collodion may be a better alternative to paste in terms of decreased artifacts

    Energy-aware Georouting with Guaranteed Delivery in Wireless Sensor Networks with Obstacles

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    International audienceWe propose, EtE, a novel end-to-end localized routing protocol for wireless sensor networks that is energy-efficient and guarantees delivery. To forward a packet, a node s in graph G computes the cost of the energy weighted shortest path between s and each of its neighbors in the forward direction towards the destination which minimizes the ratio of the cost of the shortest path to the progress (reduction in distance towards the destination). It then sends the message to the first node on the shortest path from s to x: say node x′. Node x′ restarts the same greedy rout- ing process until the destination is reached or an obstacle is encountered and the routing fails. To recover from the latter scenario, local minima trap, our algorithm invokes an energy-aware Face routing that guarantees delivery. Our work is the first to optimize energy consumption of Face routing. It works as follows. First, it builds a connected dominating set from graph G, second it computes its Gabriel graph to obtain the planar graph G′. Face routing is invoked and applied to G′ only to determine which edges to follow in the recovery process. On each edge, greedy rout- ing is applied. This two-phase (greedy-Face) End-to-End routing process (EtE) reiterates until the final destination is reached. Simulation results show that EtE outperforms several existing geographical routing on en- ergy consumption metric and delivery rate. Moreover, we prove that the computed path length and the total energy of the path are constant factors of the optimal for dense networks

    Alzheimer's disease and type 2 diabetes: the association study of polymorphisms in tumor necrosis factor-alpha and apolipoprotein E genes

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    Type 2 diabetes (T2D) and Alzheimer's disease (AD) are two progressive disorders with high prevalence worldwide. Polymorphisms in tumor necrosis factor-alpha (TNF-?) and apolipoprotein E (ApoE) genes might be associated with both T2D and AD, representing possible genetic markers for the development of the AD in subjects with T2D. The aim was to determine ApoE and G-308A TNF-? gene polymorphisms in unrelated Croatian Caucasians: 207 patients with sporadic AD, 196 T2D patients and 456 healthy controls. Patients with AD had higher frequency of ApoE4 allele compared to T2D patients and controls. The significant association, observed between ApoE2 allele and T2D, disappeared after the data were adjusted for age and sex. The genotype or allele frequencies of G-308A TNF-? gene polymorphism were similar among the patients with AD, T2D and healthy controls. In conclusion, these results do not support the hypothesis that the A allele of G-308A TNF-? gene polymorphism is associated either with AD or T2D. Our data confirm the association between the ApoE4 allele and AD, and point out the E2 allele of ApoE gene as the possible risk factor for T2D
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