90 research outputs found
Pilot scale application of ozonated water wash - effect on microbiological and sensory quality parameters of processed iceberg lettuce during self-life
The aim of the study was to assess the effect of ozonated water wash on the microbiological and sensory quality parameters of minimally processed iceberg lettuce in pilot scale in comparison to aqueous chlorine wash. Alternative solutions for chlorine are needed, since its use is prohibited in organic food processing. Iceberg lettuce samples were washed with three different ozone solutions and the water wash and the 100 ppm chlorine wash were used as control. Ozone generator based on corona discharge was used to produce ozone at level 7 ppm. The samples (150 g) packed in oriented polypropylene pouches were stored for 10 days at +5C and the microbiological and sensory quality was analysed on days 1, 6 and 10. There was no significant difference between chlorine wash samples and the samples washed 1 min in a machine with ozonated water concerning the microbiological quality. Compared with the chlorine with lower concentrations of ozone it is possible to control the microbial load. Concerning the sensory quality all samples endured all of the treatments well except the treatment with 7 ppm ozone for 5 min. As a conclusion the bubbling gaseous ozone in water can be as effective disinfection method as chlorine wash when the following processing parameters are taken into account: concentration of ozone during the whole process, exposure time, water temperature and the amount and type of the organic material
Assessing the opportunities of landfill mining as a source of critical raw materials in Europe
Many of the metals in landfill constitute valuable and scarce natural resources. It
has already been recognised that the recovery of these elements is critical for the sustainability
of a number of industries. Arsenic (which is an essential part of the production of transistors and
LEDs) is predicted to run out sometime in the next five to 50 years if consumption continues at
the present rate. Nickel used for anything involving stainless steel and platinum group metals
(PGMs) used in catalytic converters, fertilisers and others are also identified as critical materials
(CM) to the EU economy at risk of depletion However, despite the increasing demand, none of
this supply is supported by recycling. This is due to the high cost of recovery from low
concentrations when compared to conventional mining. As demonstrated by the two pilot case
studies of this study, mining landfill sites only for their metals content is not expected to be
financially viable. However, other opportunities such as Waste-derived fuels from excavated
materials exist which if combined , form the concept of ‘enhanced landfill mining’. have the
potential to be highly energetic. The energy potential is comparable to the levels of energy of
Refuse-Derived Fuels (RDF) produced from non-landfilled wastes
Quantifying uncertainty, variability and likelihood for ordinary differential equation models
<p>Abstract</p> <p>Background</p> <p>In many applications, ordinary differential equation (ODE) models are subject to uncertainty or variability in initial conditions and parameters. Both, uncertainty and variability can be quantified in terms of a probability density function on the state and parameter space.</p> <p>Results</p> <p>The partial differential equation that describes the evolution of this probability density function has a form that is particularly amenable to application of the well-known method of characteristics. The value of the density at some point in time is directly accessible by the solution of the original ODE extended by a single extra dimension (for the value of the density). This leads to simple methods for studying uncertainty, variability and likelihood, with significant advantages over more traditional Monte Carlo and related approaches especially when studying regions with low probability.</p> <p>Conclusions</p> <p>While such approaches based on the method of characteristics are common practice in other disciplines, their advantages for the study of biological systems have so far remained unrecognized. Several examples illustrate performance and accuracy of the approach and its limitations.</p
An advanced Bayesian model for the visual tracking of multiple interacting objects
Visual tracking of multiple objects is a key component of many visual-based systems. While there are reliable
algorithms for tracking a single object in constrained scenarios, the object tracking is still a challenge in
uncontrolled situations involving multiple interacting objects that have a complex dynamics. In this article, a novel
Bayesian model for tracking multiple interacting objects in unrestricted situations is proposed. This is accomplished
by means of an advanced object dynamic model that predicts possible interactive behaviors, which in turn depend
on the inference of potential events of object occlusion. The proposed tracking model can also handle false and
missing detections that are typical from visual object detectors operating in uncontrolled scenarios. On the other
hand, a Rao-Blackwellization technique has been used to improve the accuracy of the estimated object trajectories,
which is a fundamental aspect in the tracking of multiple objects due to its high dimensionality. Excellent results
have been obtained using a publicly available database, proving the efficiency of the proposed approach
Coherent control of three-spin states in a triple quantum dot
Spin qubits involving individual spins in single quantum dots or coupled
spins in double quantum dots have emerged as potential building blocks for
quantum information processing applications. It has been suggested that triple
quantum dots may provide additional tools and functionalities. These include
the encoding of information to either obtain protection from decoherence or to
permit all-electrical operation, efficient spin busing across a quantum
circuit, and to enable quantum error correction utilizing the three-spin
Greenberger-Horn-Zeilinger quantum state. Towards these goals we demonstrate
for the first time coherent manipulation between two interacting three-spin
states. We employ the Landau-Zener-St\"uckelberg approach for creating and
manipulating coherent superpositions of quantum states. We confirm that we are
able to maintain coherence when decreasing the exchange coupling of one spin
with another while simultaneously increasing its coupling with the third. Such
control of pairwise exchange is a requirement of most spin qubit architectures
but has not been previously demonstrated.Comment: 12 pages, 13 figures, and 2 table
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External ballistics of Pleistocene hand-thrown spears: experimental performance data and implications for human evolution
The appearance of weaponry - technology designed to kill - is a critical but poorly established threshold
in human evolution. It is an important behavioural marker representing evolutionary changes in
ecology, cognition, language and social behaviours. While the earliest weapons are often considered
to be hand-held and consequently short-ranged, the subsequent appearance of distance weapons is a
crucial development. Projectiles are seen as an improvement over contact weapons, and are considered
by some to have originated only with our own species in the Middle Stone Age and Upper Palaeolithic.
Despite the importance of distance weapons in the emergence of full behavioral modernity, systematic
experimentation using trained throwers to evaluate the ballistics of thrown spears during fight and at
impact is lacking. This paper addresses this by presenting results from a trial of trained javelin athletes,
providing new estimates for key performance parameters. Overlaps in distances and impact energies
between hand-thrown spears and spearthrowers are evidenced, and skill emerges as a signifcant factor in
successful use. The results show that distance hunting was likely within the repertoire of hunting strategies
of Neanderthals, and the resulting behavioural flexibility closely mirrors that of our own specie
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