453 research outputs found
Gyroscopic stabilisers for powered two-wheeled vehicles
© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. This paper illustrates the potential of a gyroscopic stabiliser for the stabilisation of single-track vehicles, at low and high speed as well as during braking. Alternative systems are considered, including single and twin counter-rotating gyroscopes, spinning and precessing with respect to different axes, either freely (passive stabilisers) or in a controlled way (active stabilisers). A suitable mathematical model has been developed and stability has been investigated both by eigenvalue calculation and time domain simulations. It has been found that the most effective configuration is one where the gyroscope(s) spin with respect to an axis parallel to the wheels' spin axis and swing with respect to the vehicle yaw axis. Passive systems may effectively stabilise both weave and wobble at medium and high speed, but cannot stabilise the vehicle at low and zero speed. On the contrary, actively controlled gyroscopes are capable of stabilising the vehicle in its whole range of operating speed, as well as during braking. The alteration of the original vehicle handling characteristics is negligible when active counter-rotating gyroscopes are used, and still acceptable if a single gyroscope is adopted instead
Series Hybrid Electric Vehicle Simultaneous Energy Management and Driving Speed Optimization
The energy management (EM) and driving speed
co-optimization of a series hybrid electric vehicle (S-HEV) for
minimizing fuel consumption is addressed in this article on the
basis of a suitably modeled series powertrain architecture. The
paper proposes a novel strategy that finds the optimal driving
speed simultaneously with the energy source power split for
the drive mission specified in terms of the road geometry and
travel time. Such a combined optimization task is formulated
as an optimal control problem that is solved by an indirect
optimal control method, based on Pontryagin’s minimum principle. The optimization scheme is tested under a rural drive
mission by extensive comparisons with conventional methods that
deal with either speed optimization only or EM strategies with
given driving cycles. The comparative results show the superior
performance of the proposed method and provide further insight
into efficient driving
Effectiveness of different modalities of psychotherapeutic treatment for patients with cluster C personality disorders: results of a large prospective multicentre study.
Abstract
BACKGROUND: No previous studies have compared the effectiveness of different modalities of psychotherapeutic treatment, as defined by different settings and durations, for patients with cluster C personality disorders. The aim of this multicentre study wa
Modelling different penetration rates of automated eco-driving electric vehicles in an urban area
Eco-driving strategies have proven to be effective in providing energy savings for the vehicle that is utilising them. This paper explores the underinvestigated impact of eco-driving vehicles on other network participants adhering to conventional driving styles. An eco-driving strategy designed for an electric vehicle that trades off energy savings with naturalistic driving without relying on vehicle-to-infrastructure or vehicle-to-vehicle communication is extended using Gaussian Process Regression for real-time predictive speed optimization. It enables the assessment of its network effects in two scenarios: 1) a platoon and 2) an urban network simulation with mixed-mode traffic and varying demand levels. Initial validation involves an eco-driving vehicle responding to a platoon leader, influencing following vehicles governed by the Intelligent Driver Model (IDM). Further analysis introduces eco-vehicles into an IDM-governed network under different traffic conditions. Energy savings of up to 21% were achieved in cars following a vehicle that prioritises energy savings and, of up to 13% if they followed a vehicle that attempts to balance energy savings and conventional driving style. In the urban scenario, positive effects on other users are observed in high density traffic even if only a small number of eco-vehicles are present in the network. The largest energy savings achieved in conventional vehicles were 5.1% and were obtained for highdensity traffic and a network consisting of 25% of eco-vehicles
Motivation of health surveillance assistants in Malawi: A qualitative study
Background: Motivation of health workers is a critical component of performance and is shaped by multiple factors. This study explored factors that influence motivation of health surveillance assistants (HSAs) in Malawi, with the aim of identifying interventions that can be applied to enhance motivation and performance of HSAs.Methods: A qualitative study capturing the perspectives of purposively selected participants was conducted in two districts: Salima and Mchinji. Participants included HSAs, health managers, and various community members. Data were collected through focus group discussions (n = 16) and in-depth interviews (n = 44). The study sample was comprised of 112 women and 65 men. Qualitative data analysis was informed by existing frameworks on factors influencing health worker motivation.Results: Our analysis identified five key themes shaping HSA motivation: salary, accommodation, human resource management, supplies and logistics, and community links. Each of these played out at different levels—individual, family, community, and organisational—with either positive or negative effects. Demotivating factors related primarily to the organisational level, while motivating factors were more often related to individual, family, and community levels. A lack of financial incentives and shortages of basic supplies and materials were key factors demotivating HSAs. Supervision was generally perceived as unsupportive, uncoordinated, and top-down. Most HSAs complained of heavy workload. Many HSAs felt further recognition and support from the Ministry of Health, and the development of a clear career pathway would improve their motivation.Conclusions: Factors shaping motivation of HSAs are complex and multilayered; experiences at one level will impact other levels. Interventions are required to enhance HSA motivation, including strengthening the supervision system, developing career progression pathways, and ensuring clear and transparent incentives. HSAs have unique experiences, and there is need to hear and address these to better enable HSAs to cope with the challenging conditions they work in
A systematic approach to generating accurate neural network potentials: the case of carbon
Availability of affordable and widely applicable interatomic potentials is the key needed to unlock the riches of modern materials modeling. Artificial neural network-based approaches for generating potentials are promising; however, neural network training requires large amounts of data, sampled adequately from an often unknown potential energy surface. Here we propose a self-consistent approach that is based on crystal structure prediction formalism and is guided by unsupervised data analysis, to construct an accurate, inexpensive, and transferable artificial neural network potential. Using this approach, we construct an interatomic potential for carbon and demonstrate its ability to reproduce first principles results on elastic and vibrational properties for diamond, graphite, and graphene, as well as energy ordering and structural properties of a wide range of crystalline and amorphous phases
Longitudinal study of computerised cardiotocography in early fetal growth restriction.
OBJECTIVES: To explore if in early fetal growth restriction (FGR) the longitudinal pattern of short-term fetal heart rate (FHR) variation (STV) can be used for identifying imminent fetal distress and if abnormalities of FHR registration associate with two-year infant outcome. METHODS: The original TRUFFLE study assessed if in early FGR the use of ductus venosus Doppler pulsatility index (DVPI), in combination with a safety-net of very low STV and / or recurrent decelerations, could improve two-year infant survival without neurological impairment in comparison to computerised cardiotocography (cCTG) with STV calculation only. For this secondary analysis we selected women, who delivered before 32 weeks, and who had consecutive STV data for more than 3 days before delivery, and known infant two-year outcome data. Women who received corticosteroids within 3 days of delivery were excluded. Individual regression line algorithms of all STV values except the last one were calculated. Life table analysis and Cox regression analysis were used to calculate the day by day risk for a low STV or very low STV and / or FHR decelerations (DVPI group safety-net) and to assess which parameters were associated to this risk. Furthermore, it was assessed if STV pattern, lowest STV value or recurrent FHR decelerations were associated with two-year infant outcome. RESULTS: One hundred and fourty-nine women matched the inclusion criteria. Using the individual STV regression lines prediction of a last STV below the cCTG-group cut-off had a sensitivity of 0.42 and specificity of 0.91. For each day after inclusion the median risk for a low STV(cCTG criteria) was 4% (Interquartile range (IQR) 2% to 7%) and for a very low STV and / or recurrent decelerations (DVPI safety-net criteria) 5% (IQR 4 to 7%). Measures of STV pattern, fetal Doppler (arterial or venous), birthweight MoM or gestational age did not improve daily risk prediction usefully. There was no association of STV regression coefficients, a last low STV or /and recurrent decelerations with short or long term infant outcomes. CONCLUSION: The TRUFFLE study showed that a strategy of DVPI monitoring with a safety-net delivery indication of very low STV and / or recurrent decelerations could increase infant survival without neurological impairment at two years. This post-hoc analysis demonstrates that in early FGR the day by day risk of an abnormal cCTG as defined by the DVPI protocol safety-net criteria is 5%, and that prediction of this is not possible. This supports the rationale for cCTG monitoring more often than daily in these high-risk fetuses. Low STV and/or recurrent decelerations were not associated with adverse infant outcome and it appears safe to delay intervention until such abnormalities occur, as long as DVPI is in the normal range
Push-Pull Bis-Norbornadienes for Solar Thermal Energy Storage
The norbornadiene/quadricyclane (NBD/QC) photoswitch pair represents a promising system for application in molecular solar thermal energy storage (MOST). Often, the NBD derivatives have very limited overlap with the solar spectrum, and substitution to redshift the absorption leads to a decrease in the gravimetric energy density. Dimeric systems mitigate this factor because two switches can ‘share’ a substituent. Here, we present five new NBD dimers with red-shifted absorption spectra. One dimer features the most red-shifted absorption onset (539 nm) and a significantly red-shifted absorption maximum (404 nm) for NBD systems reported so far, without compromising thermal half-life. Promising properties for high-performance MOST applications are demonstrated, such as high absorption onsets reaching 539 nm, and energy densities of 379 kJ/kg, while still maintaining long half-lives of the metastable isomer, up to 23 hours at 25 °C
Abstracts of presentations on plant protection issues at the xth international congress of virology: August 11-16,1996 Binyanei haOoma, Jerusalem, Israel Part 2 Plenary Lectures
Genomic and biological characterization of chiltepin yellow mosaic virus, a new tymovirus infecting Capsicum annuum var. aviculare in Mexico.
The characterization of viruses infecting wild plants is a key step towards understanding the ecology of plant viruses. In this work, the complete genomic nucleotide sequence of a new tymovirus species infecting chiltepin, the wild ancestor of Capsicum annuum pepper crops, in Mexico was determined, and its host range has been explored. The genome of 6,517 nucleotides has the three open reading frames described for tymoviruses, putatively encoding an RNA-dependent RNA polymerase, a movement protein and a coat protein. The 5′ and 3′ untranslated regions have structures with typical signatures of the tymoviruses. Phylogenetic analyses revealed that this new virus is closely related to the other tymoviruses isolated from solanaceous plants. Its host range is mainly limited to solanaceous species, which notably include cultivated Capsicum species. In the latter, infection resulted in a severe reduction of growth, indicating the potential of this virus to be a significant crop pathogen. The name of chiltepin yellow mosaic virus (ChiYMV) is proposed for this new tymovirus
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