986 resultados para DIPOLE-MOMENTS


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Rapid development of plug-in hybrid electric vehicles (PHEVs) brings new challenges and opportunities to the power industry. A large number of idle PHEVs can potentially be employed to form a distributed energy storage system for supporting renewable generation. To reduce the negative effects of unsteady renewable generation outputs, a stochastic optimization-based dispatch model capable of handling uncertain outputs of PHEVs and renewable generation is formulated in this paper. The mathematical expectations, second-order original moments, and variances of wind and photovoltaic (PV) generation outputs are derived analytically. Incorporated all the derived uncertainties, a novel generation shifting objective is proposed. The cross-entropy (CE) method is employed to solve this optimal dispatch model. Multiple patterns of renewable generation depending on seasons and renewable market shares are investigated. The feasibility and efficiency of the developed optimal dispatch model, as well as the CE method, are demonstrated with a 33-node distribution system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background The use of dual growing rods is a fusionless surgical approach to the treatment of early onset scoliosis (EOS), which aims of harness potential growth in order to correct spinal deformity. The purpose of this study was to compare the in-vitro biomechanical response of two different dual rod designs under axial rotation loading. Methods Six porcine spines were dissected into seven level thoracolumbar multi-segmental units. Each specimen was mounted and tested in a biaxial Instron machine, undergoing nondestructive left/right axial rotation to peak moments of 4Nm at a constant rotation rate of 8deg.s-1. A motion tracking system (Optotrak) measured 3D displacements of individual vertebrae. Each spine was tested in an un-instrumented state first and then with appropriately sized semi-constrained growing rods and ‘rigid’ rods in alternating sequence. Range of motion, neutral zone size and stiffness were calculated from the moment-rotation curves and intervertebral ranges of motion were calculated from Optotrak data. Findings Irrespective of test sequence, rigid rods showed significantly reduction of total rotation across all instrumented levels (with increased stiffness) whilst semi-constrained rods exhibited similar rotation behavior to the un-instrumented (P<0.05). An 11% and 8% increase in stiffness for left and right axial rotation respectively and 15% reduction in total range of motion was recorded with dual rigid rods compared with semi-constrained rods. Interpretation Based on these findings, the semi-constrained growing rods do not increase axial rotation stiffness compared with un-instrumented spines. This is thought to provide a more physiological environment for the growing spine compared to dual rigid rod constructs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this chapter we consider how the iPad and selected applications such as Draw and Tell (Duck Duck Moose, 2013), Popplet (Notion Inc., 2013) and Puppet Pals (Polished Play LLC, 2013) can assist children in collaborative storying, retelling and sequencing story moments that can assist young children in their acquisition of oracy and their understanding of the world, both real and imagined, and their personal relationships. The data gathered from the project will also analysed through the lense of “critical and creative thinking” (ACARA, 2013, p.20-21) skills articulated as one of the general capabilities required in all subject areas of the Australian national curriculum, but which has particular application to The Arts subject areas. In this chapter, we consider artefacts created by preschool children using iPads and selected apps and interviews conducted with preschool children and their caregivers during our research project. We then offer examples of practice to assist preschool teachers in supporting children in their storymaking using the iPad and discuss approaches for engagement that twins the live and mediatised representation of a story.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper analyses qualitative data with LGBT young people to think about police-LGBT youth interactions, and the outcomes of these interactions, as pedagogical moments for LGBT young people, police, and public onlookers. Although the data in this paper could be interpreted in line with dominant ways of thinking about LGBT young people and police, as criminalization for instance, the data suggested something more complex. This paper employs a theoretical framework informed by poststructural theories, queer theories, and pedagogical theories, to theorise LGBT youth-police interactions as instruction about managing police relationships in public spaces. The analysis shows how LGBT young people are learning from police encounters about the need to avoid ‘looking queer’ to minimise police harm.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper presents an approach to mobile robot localization, place recognition and loop closure using a monostatic ultra-wide band (UWB) radar system. The UWB radar is a time-of-flight based range measurement sensor that transmits short pulses and receives reflected waves from objects in the environment. The main idea of the poposed localization method is to treat the received waveform as a signature of place. The resulting echo waveform is very complex and highly depends on the position of the sensor with respect to surrounding objects. On the other hand, the sensor receives similar waveforms from the same positions.Moreover, the directional characteristics of dipole antenna is almost omnidirectional. Therefore, we can localize the sensor position to find similar waveform from waveform database. This paper proposes a place recognitionmethod based on waveform matching, presents a number of experiments that illustrate the high positon estimation accuracy of our UWB radar-based localization system, and shows the resulting loop detection performance in a typical indoor office environment and a forest.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

My concern in this commentary is the discrepancy between cultural psychologists' theoretical claims that meanings are co-constructed by, with and for individuals in ongoing social interaction, and their research practices where researcher's and research participant's meaning-making processes are separated in time into sequential turns. I argue for the need to live up to these theoretical assumptions, by making both the initial research encounter and the researcher's later interpretation process more co-constructive. I suggest making the initial research encounter more co-constructive by paying attention to these moments when the negotiated flow of interaction between researcher and research participant breaks down, for it allows the research participant's meaning-making to be traced and makes the researcher's efforts towards meaning more explicit. I propose to make the later interpretation process more co-constructive by adopting a more open-ended and dialogical way of writing that is specifically addressed to research participants and invites them to actively engage with researcher's meaning-making.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper aims to provide a contextualised and embedded exploration of how the notions of "practice" and "participation", key concepts in the study of culture and media, are manifest in an example of a complex creative project. This project aimed to engage with refugees and asylum seekers through the co-creation of cultural material and is an outcome of an? ethnographic action research (Tacchi et al. 2003) partnership involving a community development worker in a settlement support agency and a storytelling/community media researcher (the author), along with other project collaborators. The discussion of this project focuses on the role of the facilitator and illustrates the processes of orchestrating a complex project involving a series of linked stages with cumulative effect. As practitioners at this site we are working in the space where personal narratives, participatory arts and media, and the staging of intercultural, civic dialogue events, intersect. Co-creative media facilitation in these contexts involves both managing hybrid communicative spaces and (re)combining the "integrative practices" (Schatzki 1996) of a range of professional approaches and creative roles. This is liminal work, located on the boundaries of several disciplines and practices. Drawing on reflections gathered from collaborative ethnographic descriptions (Bhattacharya 2008), this paper traces moments of practitioner uncertainty that can be linked to the way "practice" and “participation” is problematised within the community cultural development field in a way that is at times an uneasy fit with conventional ways of operating in social service roles. These moments of tension also indicate where this project pushed practitioners into spaces of improvisation and new learning. Keywords: Youth, refugees, community cultural development, co-creative media facilitation, ethnographic action research, intercultural dialogue.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper addresses the role of photography as a documentary medium and how this forms a basis for my practice-led studio investigations. In it, I will explore how photography is used to create histories and sustain specific notions of ‘legacy’ within the context of the family photo album. Family history is often based on stories to which the photo album provides a visual point of reference. Despite the ostensible ‘objectivity’ of the family photograph though it is nonetheless as subjective as the stories that surround it. In this way, the photo album perpetuates a hegemony of truth that obscures the fragmentary and highly selective nature of these documents and stories. The result is that every photo album implicitly documents the gaps or voids present in understandings of our own histories. Homi Bhabha refers to these kinds of voids as ‘disjunctive historical spaces’ – spaces of slippage that create the opportunity for new narratives and understandings to occur. Using Bhabha’s ideas as a chief point of reference, I will explore how these voids or gaps in information – and the opportunities for re-examination that they open up - can be explored through contemporary photomedia. Digital technologies such as camera phones and scanners generate a space in which photography’s own documentary conventions can be turned in on themselves to create a subterfuge. My current studio-based research involves using the scanner to navigate through my family’s sometimes-‘occulted’ history, in order to explore, document and recover my connection to this narrative. I am primarily interested in the scanner as a tool for capturing not simply surfaces, but objects, moments or movements in time. Objects or moments captured by the scanner can often be simultaneously distorted and consolidated, blurred and sharpened. This paper will propose that this ‘slippage’, literally expressed in the disruption of the pixelated field, can be used to create a space in which alternative readings or understandings of past events can be explored and new narratives produced.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The rehabilitation programs of bone-anchorage prostheses relying either on the OPRA (Integrum, Sweden) or the ILP (Orthodynamics, Germany) fixation involve some forms of static load bearing exercises (LBE). So far, most of biomechanical studies of these static LBEs focused on the direct measurements of the actual forces and moments applied on the OPRA fixation of individuals with transfemoral amputation (TFA). To date, the proof-of-concept of an apparatus to conduct these kinetic measurements has been presented, along with some preliminary data. The understanding of the kinetic data is essential to improve rehabilitation programs as well as the design of upcoming loading frames. However, kinetic information alone is difficult to interpret without concomitant kinematic data. The purpose of this preliminary study was to introduce a qualitative analysis describing the different body postures during LBE for a group of TFAs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Individuals with lower limb amputation fitted with an OPRA osseointegrated fixation are facing an extensive rehabilitation program including static load bearing exercises (LBE). The application of a suitable amount of stress stimulates osseointegration and prepares the bone to tolerate the forces and moments that will be incurred during activities of daily living (ADL. At present, the monitoring is typically carried out using a normal bathroom weighing scale. This scale provides information only on the magnitude of the vertical component of the applied force. The moment around the long axis of the fixation when the femur is perpendicular to the ground is not assessed and neither are the components of force and moment generated on the other two axes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Joint moments and joint powers are widely used to determine the effects of rehabilitation programs and prosthetic components (e.g., alignments). A complementary analysis of the 3D angle between joint moment and joint angular velocity has been proposed to assess whether the joints are predominantly driven or stabilized.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The desire to solve problems caused by socket prostheses in transfemoral amputees and the acquired success of osseointegration in the dental application has led to the introduction of osseointegration in the orthopedic surgery. Since its first introduction in 1990 in Gothenburg Sweden the osseointegrated (OI) orthopedic fixation has proven several benefits[1]. The surgery consists of two surgical procedures followed by a lengthy rehabilitation program. The rehabilitation program after an OI implant includes a specific training period with a short training prosthesis. Since mechanical loading is considered to be one of the key factors that influence bone mass and the osseointegration of bone-anchored implants, the rehabilitation program will also need to include some form of load bearing exercises (LBE). To date there are two frequently used commercially available human implants. We can find proof in the literature that load bearing exercises are performed by patients with both types of OI implants. We refer to two articles, a first one written by Dr. Aschoff and all and published in 2010 in the Journal of Bone and Joint Surgery.[2] The second one presented by Hagberg et al in 2009 gives a very thorough description of the rehabilitation program of TFA fitted with an OPRA implant. The progression of the load however is determined individually according to the residual skeleton’s quality, pain level and body weight of the participant.[1] Patients are using a classical bathroom weighing scale to control the load on the implant during the course of their rehabilitation. The bathroom scale is an affordable and easy-to-use device but it has some important shortcomings. The scale provides instantaneous feedback to the patient only on the magnitude of the vertical component of the applied force. The forces and moments applied along and around the three axes of the implant are unknown. Although there are different ways to assess the load on the implant for instance through inverse dynamics in a motion analysis laboratory [3-6] this assessment is challenging. A recent proof- of-concept study by Frossard et al (2009) showed that the shortcomings of the weighing scale can be overcome by a portable kinetic system based on a commercial transducer[7].

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study aimed at presenting the intra-tester reliability of the static load bearing exercises (LBEs) performed by individuals with transfemoral amputation (TFA) fitted with an osseointegrated implant to stimulate the bone remodelling process. There is a need for a better understanding of the implementation of these exercises particularly the reliability. The intra-tester reliability is discussed with a particular emphasis on inter-load prescribed, inter-axis and inter-component reliabilities as well as the effect of body weight normalisation. Eleven unilateral TFAs fitted with an OPRA implant performed five trials in four loading conditions. The forces and moments on the three axes of the implant were measured directly with an instrumented pylon including a six-channel transducer. Reliability of loading variables was assessed using intraclass correlation coefficients (ICCs) and percentage standard error of measurement values (%SEMs). The ICCs of all variables were above 0.9 and the %SEM values ranged between 0 and 87%. This study showed a high between-participants’ variance highlighting the lack of loading consistency typical of symptomatic population as well as a high reliability between the loading sessions indicating a plausible correct repetition of the LBE by the participants. However, these outcomes must be understood within the framework of the proposed experimental protocol.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper aims to develop a more nuanced analytic vocabulary to typify how and where classroom trouble can manifest in pedagogic discourse. It draws on classroom ethnographies conducted in non-academic secondary school pathways and alternative programs in Australian communities with high youth unemployment, where the policy of ‘earning or learning’ till age 17 has effectively extended compulsory schooling. Three concepts are developed and exemplified: ‘regulative flares’, being moments when teachers resort to explicitly reasserting the lesson’s social order; ‘moral gravity’ to describe the degree to which the moral order underpinning the regulative discourse is tied to the immediate context or beyond; and ‘instructional elasticity’ to account for trouble originating in the instructional register.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The consequences of falls are often dreadful for individuals with lower limb amputation using bone-anchored prosthesis.[1-5] Typically, the impact on the fixation is responsible for bending the intercutaneous piece that could lead to a complete breakage over time. .[3, 5-8] The surgical replacement of this piece is possible but complex and expensive. Clearly, there is a need for solid data enabling an evidence-based design of protective devices limiting impact forces and torsion applied during a fall. The impact on the fixation during an actual fall is obviously difficult to record during a scientific experiment.[6, 8-13] Consequently, Schwartze and colleagues opted for one of the next best options science has to offer: simulation with an able-bodied participant. They recorded body movements and knee impacts on the floor while mimicking several plausible falling scenarios. Then, they calculated the forces and moments that would be applied at four levels along the femur corresponding to amputation heights.[6, 8-11, 14-25] The overall forces applied during the falls were similar regardless of the amputation height indicating that the impact forces were simply translated along the femur. As expected, they showed that overall moments generally increased with amputation height due to changes in lever arm. This work demonstrates that devices preventing only against force overload do not require considering amputation height while those protecting against bending moments should. Another significant contribution is to provide, for the time, the magnitude of the impact load during different falls. This loading range is crucial to the overall design and, more precisely, the triggering threshold of protective devices. Unfortunately, the analysis of only a single able-bodied participant replicating falls limits greatly the generalisation of the findings. Nonetheless, this case study is an important milestone contributing to a better understanding of load impact during a fall. This new knowledge will improve the treatment, the safe ambulation and, ultimately, the quality of life of individuals fitted with bone-anchored prosthesis.