1,741 research outputs found
Investigation of thin n-in-p planar pixel modules for the ATLAS upgrade
In view of the High Luminosity upgrade of the Large Hadron Collider (HL-LHC),
planned to start around 2023-2025, the ATLAS experiment will undergo a
replacement of the Inner Detector. A higher luminosity will imply higher
irradiation levels and hence will demand more ra- diation hardness especially
in the inner layers of the pixel system. The n-in-p silicon technology is a
promising candidate to instrument this region, also thanks to its
cost-effectiveness because it only requires a single sided processing in
contrast to the n-in-n pixel technology presently employed in the LHC
experiments. In addition, thin sensors were found to ensure radiation hardness
at high fluences. An overview is given of recent results obtained with not
irradiated and irradiated n-in-p planar pixel modules. The focus will be on
n-in-p planar pixel sensors with an active thickness of 100 and 150 um recently
produced at ADVACAM. To maximize the active area of the sensors, slim and
active edges are implemented. The performance of these modules is investigated
at beam tests and the results on edge efficiency will be shown
Magnetic field tunable terahertz quantum well infrared photodetector
A theoretical model and a design of a magnetic field tunable CdMnTe/CdMgTe terahertz quantum
well infrared photodetector are presented. The energy levels and the corresponding wavefunctions
were computed from the envelope function Schr¨odinger equation using the effective mass
approximation and accounting for Landau quantization and the giant Zeeman effect induced by
magnetic confinement. The electron dynamics were modeled within the self-consistent coupled rate
equations approach, with all relevant electron-longitudinal optical phonon and electron-longitudinal
acoustic phonon scattering included. A perpendicular magnetic field varying between 0 T and 5 T,
at a temperature of 1.5 K, was found to enable a large shift of the detection energy, yielding a
tuning range between 24.1 meV and 34.3 meV, equivalent to 51.4 μm to 36.1 μm wavelengths. For
magnetic fields between 1 T and 5 T, when the electron population of the QWIP is spin-polarized,
a reasonably low dark current of ≤1.4×10–² A/cm² and a large responsivity of 0.36−0.64 A/W
are predicted
Lost in optimisation of water distribution systems? A literature review of system operation
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Optimisation of the operation of water distribution systems has been an active research field for almost half a
century. It has focused mainly on optimal pump operation to minimise pumping costs and optimal water
quality management to ensure that standards at customer nodes are met. This paper provides a systematic
review by bringing together over two hundred publications from the past three decades, which are relevant to
operational optimisation of water distribution systems, particularly optimal pump operation, valve control
and system operation for water quality purposes of both urban drinking and regional multiquality water
distribution systems. Uniquely, it also contains substantial and thorough information for over one hundred
publications in a tabular form, which lists optimisation models inclusive of objectives, constraints, decision
variables, solution methodologies used and other details. Research challenges in terms of simulation models,
optimisation model formulation, selection of optimisation method and postprocessing needs have also been
identified
Lost in optimisation of water distribution systems? A literature review of system design
This is the final version of the article. Available from MDPI via the DOI in this record.Optimisation of water distribution system design is a well-established research field, which has been extremely productive since the end of the 1980s. Its primary focus is to minimise the cost of a proposed pipe network infrastructure. This paper reviews in a systematic manner articles published over the past three decades, which are relevant to the design of new water distribution systems, and the strengthening, expansion and rehabilitation of existing water distribution systems, inclusive of design timing, parameter uncertainty, water quality, and operational considerations. It identifies trends and limits in the field, and provides future research directions. Exclusively, this review paper also contains comprehensive information from over one hundred and twenty publications in a tabular form, including optimisation model formulations, solution methodologies used, and other important details
Human-Evolutionary Problem Solving through Gamification of a Bin-Packing Problem
This is the author accepted manuscript. The final version is available from ACM via the DOI in this recordMany complex real-world problems such as bin-packing are
optimised using evolutionary computation (EC) techniques.
Involving a human user during this process can avoid producing
theoretically sound solutions that do not translate to the real world
but slows down the process and introduces the problem of user
fatigue. Gamification can alleviate user boredom, concentrate user
attention, or make a complex problem easier to understand. This
paper explores the use of gamification as a mechanism to extract
problem-solving behaviour from human subjects through
interaction with a gamified version of the bin-packing problem,
with heuristics extracted by machine learning. The heuristics are
then embedded into an evolutionary algorithm through the
mutation operator to create a human-guided algorithm.
Experimentation demonstrates that good human performers
augment EA performance, but that poorer performers can be
detrimental to it in certain circumstances. Overall, the introduction
of human expertise is seen to benefit the algorithm
Histologija jetre i variranje površine jedara hepatocita pastrmke gajene u kaveznom sistemu
U hidroakumulacionom jezeru ”Bočac” gajena je kalifornijska pastrmka (Oncorhynchus mykiss, Walbaum, 1792) u dva odvojena eksperimenta u trajanju od po 90 dana – jedan u periodu jesen – zima, a drugi u periodu proleće – leto. Pastrmke su hranjene sa šest različitih komercijalnih hraniva i ispitivan je njihov uticaj na histološku gradju jetre riba. U eksperimentu je preovladavala normalna histološka građa jetre, a malobrojne histopatološke promene koje su uočene se mogu pripisati periodu godine i sastavu hrane. Kvantifikacija rezultata je pokazala da se sa rastom temperature vode i količine hrane kojom su ribe hranjene, prosečna površina jedara hepatocita povećava, dok se sa opadanjem temperature i količine hrane prosečna površina jedara hepatocita povećava, nezavisno od tipa hrane koja je korišćena
Radiation hardness of small-pitch 3D pixel sensors up to HL-LHC fluences
A new generation of 3D silicon pixel detectors with a small pixel size of
5050 and 25100 m is being developed for the HL-LHC
tracker upgrades. The radiation hardness of such detectors was studied in beam
tests after irradiation to HL-LHC fluences up to
n/cm. At this fluence, an operation voltage of only 100 V
is needed to achieve 97% hit efficiency, with a power dissipation of 13
mW/cm at -25C, considerably lower than for previous 3D sensor
generations and planar sensors.Comment: 5 pages, 2 figures, Proceedings of TIPP 2017, Beijing (International
Conference on The Technology and Instrumentation in Particle Physics 2017
On the coherence/incoherence of electron transport in semiconductor heterostructure optoelectronic devices
This paper compares and contrasts different theoretical approaches based on incoherent electron scattering transport with experimental measurements of optoelectronic devices formed from semiconductor heterostructures. The Monte Carlo method which makes no a priori assumptions about the carrier distribution in momentum or phase space is compared with less computationally demanding energy-balance rate equation models which assume thermalised carrier distributions. It is shown that the two approaches produce qualitatively similar results for hole transport in p-type Si1-xGex/Si superlattices designed for terahertz emission. The good agreement of the predictions of rate equation calculations with experimental measurements of mid- and far-infrared quantum cascade lasers, quantum well infrared photodetectors and quantum dot infrared photodetectors substantiate the assumption of incoherent scattering dominating the transport in these quantum well based devices. However, the paper goes on to consider the possibility of coherent transport through the density matrix method and suggests an experiment that could allow coherent and incoherent transport to be distinguished from each other
Using a systematic, multi-criteria decision support framework to evaluate sustainable drainage designs
Open Access journalCopyright © 2013 The Authors. Published by Elsevier Ltd.12th International Conference on Computing and Control for the Water Industry, CCWI2013The conventional drainage design approach does not address sustainability issues. Moving forward, an alternative approach using green infrastructures is recommended. In addition to flow and flood management provided by the conventional methods, green infrastructures can bring multiple benefits such as increased amenity value and groundwater recharge. Unlike the traditional practice, the new approach lacks supporting technical references and software. Stakeholders are discouraged by the uncertainty of performance and costs associated with green infrastructures. We aim to bridge this knowledge gap by providing a systematic decision support framework. This paper provides an overview of the evaluation framework with some application examples
Influence of Intensive Animal Breeding to the Appearance of Infectious Diseases (Zoonoses)
Intensive animal breeding and production is based on farm breeding of animals which represents a major source of raw material for food production. Preserving health of animals requires a good practice during breeding, appropriate feeding and watering, adequate control of pests and wild animals. Animal breeding and production of food of animal origin requires significant engagement of veterinary services within the frame of epizootiological, epidemiological, veterinary and sanitary surveillance. Farm manner of cattle breeding can represent a danger of air, water and ground contamination. In the farms situated in a small space, overcrowded with animals there are ideal conditions for the appearance and spreading of causative agent of infectious diseases (prions, viruses, rickettsiae, chlamydia, bacteria, parasites and fungi), which can be transmitted also to humans and wild animals. From the aspect of public health, special attention should be given to the farms with large number of animals and farms with intensive breeding conditions. This is especially important in pig and poultry breeding, where moderate or high prevalence of infections such as salmonellosis and campylobacteriosis are often present, regardless of the fact that the level of clinical illness caused by these infections is relatively low. Intensive production in animal husbandry leads to increased animal waste, and the richest source of infectious agents represents animal feces
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