40,351 research outputs found
Project Tektite 1 - A multiagency 60 day saturated dive conducted by the United States Navy, the National Aeronautics and Space Administration, the Department of the Interior, and the General Electric Company Summary report
Underwater research in ocean floor habitat for 60 day evaluation of supporting facilities at Virgin Islands for Tektite 1 projec
Beyond capitalism and liberal democracy: on the relevance of GDH Cole’s sociological critique and alternative
This article argues for a return to the social thought of the often ignored early 20th-century English thinker GDH Cole. The authors contend that Cole combined a sociological critique of capitalism and liberal democracy with a well-developed alternative in his work on guild socialism bearing particular relevance to advanced capitalist societies. Both of these, with their focus on the limitations on ‘free communal service’ in associations and the inability of capitalism to yield emancipation in either production or consumption, are relevant to social theorists looking to understand, critique and contribute to the subversion of neoliberalism. Therefore, the authors suggest that Cole’s associational sociology, and the invitation it provides to think of formations beyond capitalism and liberal democracy, is a timely and valuable resource which should be returned to
System and method for moving a probe to follow movements of tissue
An apparatus is described for moving a probe that engages moving living tissue such as a heart or an artery that is penetrated by the probe, which moves the probe in synchronism with the tissue to maintain the probe at a constant location with respect to the tissue. The apparatus includes a servo positioner which moves a servo member to maintain a constant distance from a sensed object while applying very little force to the sensed object, and a follower having a stirrup at one end resting on a surface of the living tissue and another end carrying a sensed object adjacent to the servo member. A probe holder has one end mounted on the servo member and another end which holds the probe
Overview of SERI's high efficiency solar cell research
The bulk of the research efforts supported by the Solar Energy Research Institute (SERI) High Efficiency Concepts area has been directed towards establishing the feasibility of achieving very high efficiencies, 30% for concentrator and more than 20% for thin film flat plate, in solar cell designs which could possibly be produced competitively. The research has accomplished a great deal during the past two years. Even though the desired performance levels have not yet been demonstrated, based on the recent progress, a greater portion of the terrestrial photovoltaics community believes that these efficiencies are attainable. The program will now allocate a larger portion of resources to low cost, large area deposition technology. The program is currently shifting greater emphasis on to the study of crystal growth in order to provide the understanding and tools needed to design a large area process
Community repair: enabling repair as part of the movement towards a circular economy
Executive summary:
Repair in the context of the circular economy.
The growth in sales of household electrical and electronic equipment in recent years, combined with faster product obsolescence, has resulted in waste electrical and electronic equipment becoming the fastest growing waste stream globally (Baldé, Wang, Kuehr, & Huisman, 2015). Many products develop simple faults which are challenging for the amateur to repair; this quite often results in replacement
products being purchased and equipment with small faults being disposed of, or hoarded (Green Alliance, 2015; WRAP, 2011a). It is within this context that innovative approaches to repair are emerging in the UK, with communitybased
organisations focused on enabling consumers to attempt to repair a variety of products including clothing and electrical equipment. Access to information, spare parts and tools is being made available by companies like iFixit, providing consumers with the resources they need to attempt their own repairs. Some consumers, however, lack the skills, knowledge or confidence to attempt repairs, even when the resources are available. This report focuses on the work of the London-based Restart Project, who organise community-based events to assist these consumers. Volunteers acting as "Repair Coaches" at Restart Project repair events offer support and guidance to participants, enabling
them to attempt to repair items that they may not have had the knowledge, skills or confidence to undertake previously.
This report presents the findings from a survey with 99 participants undertaken at Restart Project events in late 2016.
Key points to emerge are:
- Many people (45%) cannot name a commercial repairer that they trust. The lack of knowledge of existing repair ventures and lack of trust in commercial repairers is a key issue to address.
- Very few respondents were "extremely" confident in undertaking repairs at home (8%), many more were "somewhat" or "moderately" confident (33%) and 47% were only "slightly"
or "not at all" confident.
- Many of the respondents reported that they have previously attempted some kind of repairs at home (56%). However, they report varying levels of success with previous repairs and cite knowledge, skills and confidence as major barriers to further attempts at repair. It is these very barriers that The Restart Project addresses.
- Respondents report that they are avid seekers of reuse options for their products when they no longer require them, with 82% reporting they looked for people to reuse items they no longer had a use for.
- Small electrical and electronic items were not recycled by as many of the respondents as other types of household items. The Restart Project appears to have a role to play as
'environmental educator' in inspiring additional recycling within the community.
Throughout the research, participants said they particularly valued the social aspect of the repair events. Feedback shows that there are high satisfaction levels with the events, even when repairs to the objects participants have brought along have been unsuccessful. Working in a social environment, meeting others with shared interests and learning or passing on repair skills in this way appears to
offer considerable potential to empower communities to attempt repairs and thereby extend the lifetime of products.
The repair network is complex and fragmented. Availability, location and consumer confidence in local repair networks, together with knowledge and skills are key issues that have emerged from this study. Informal community-based enterprises such as The Restart Project appear ideally placed to develop local responses to the gap in trust of existing networks revealed by this research, and that they have an important role to play in contributing to the circular economy
Measuring the temperature dependence of individual two-level systems by direct coherent control
We demonstrate a new method to directly manipulate the state of individual
two-level systems (TLS) in phase qubits. It allows one to characterize the
coherence properties of TLS using standard microwave pulse sequences, while the
qubit is used only for state readout. We apply this method to measure the
temperature dependence of TLS coherence for the first time. The energy
relaxation time is found to decrease quadratically with temperature for
the two TLS studied in this work, while their dephasing time measured in Ramsey
and spin-echo experiments is found to be limited at all temperatures.Comment: 4 pages, 5 figure
Single atom-scale diamond defect allows large Aharonov-Casher phase
We propose an experiment that would produce and measure a large
Aharonov-Casher (A-C) phase in a solid-state system under macroscopic motion. A
diamond crystal is mounted on a spinning disk in the presence of a uniform
electric field. Internal magnetic states of a single NV defect, replacing
interferometer trajectories, are coherently controlled by microwave pulses. The
A-C phase shift is manifested as a relative phase, of up to 17 radians, between
components of a superposition of magnetic substates, which is two orders of
magnitude larger than that measured in any other atom-scale quantum system.Comment: 5 pages, 2 figure
Dual-probe decoherence microscopy: Probing pockets of coherence in a decohering environment
We study the use of a pair of qubits as a decoherence probe of a non-trivial
environment. This dual-probe configuration is modelled by three
two-level-systems which are coupled in a chain in which the middle system
represents an environmental two-level-system (TLS). This TLS resides within the
environment of the qubits and therefore its coupling to perturbing fluctuations
(i.e. its decoherence) is assumed much stronger than the decoherence acting on
the probe qubits. We study the evolution of such a tripartite system including
the appearance of a decoherence-free state (dark state) and non-Markovian
behaviour. We find that all parameters of this TLS can be obtained from
measurements of one of the probe qubits. Furthermore we show the advantages of
two qubits in probing environments and the new dynamics imposed by a TLS which
couples to two qubits at once.Comment: 29 pages, 10 figure
Nonlinear interplay of Alfven instabilities and energetic particles in tokamaks
The confinement of energetic particles (EP) is crucial for an efficient
heating of tokamak plasmas. Plasma instabilities such as Alfven Eigenmodes (AE)
can redistribute the EP population making the plasma heating less effective,
and leading to additional loads on the walls. The nonlinear dynamics of
toroidicity induced AE (TAE) is investigated by means of the global gyrokinetic
particle-in-cell code ORB5, within the NEMORB project. The nonperturbative
nonlinear interplay of TAEs and EP due to the wave-particle nonlinearity is
studied. In particular, we focus on the nonlinear modification of the
frequency, growth rate and radial structure of the TAE, depending on the
evolution of the EP distribution in phase space. For the ITPA benchmark case,
we find that the frequency increases when the growth rate decreases, and the
mode shrinks radially. This nonlinear evolution is found to be correctly
reproduced by means of a quasilinear model, namely a model where the linear
effects of the nonlinearly modified EP distribution function are retained.Comment: Submitted to Plasma Phys. Control. Fusio
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