1,545 research outputs found

    A Technique for Collecting Water Samples Under Extreme Winter Conditions

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    A Review on Applications of Machine Learning in Shipping Sustainability

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    The shipping industry faces a significant challenge as it needs to significantly lower the amounts of Green House Gas emissions at the same time as it is expected to meet the rising demand. Traditionally, optimising the fuel consumption for ships is done during the ship design stage and through operating it in a better way, for example, with more energy-efficient machinery, optimising the speed or route. During the last decade, the area of machine learning has evolved significantly, and these methods are applicable in many more fields than before. The field of ship efficiency improvement by using Machine Learning methods is significantly progressing due to the available volumes of data from online measuring, experiments and computations. This amount of data has made machine learning a powerful tool that has been successfully used to extract information and intricate patterns that can be translated into attractive ship energy savings. This article presents an overview of machine learning, current developments, and emerging opportunities for ship efficiency. This article covers the fundamentals of Machine Learning and discusses the methodologies available for ship efficiency optimisation. Besides, this article reveals the potentials of this promising technology and future challenges

    Impact of the 2003 Illinois Gaming Tax Rate Increase on Marketing Spending

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    The purpose of this research is to investigate a potential consequence related to the 2003 Illinois Gaming Tax rate restructuring. Specifically, did the assessment of a higher gaming tax rate in the state of Illinois negatively impact promotional spending by an Illinois riverboat operator in an attempt to limit revenues and avoid incurring a higher tax rate? Data were contributed by a major Illinois riverboat operator and the researchers utilized an Autoregressive Integrated Moving Average (ARIMA) method for analysis of the data. The findings demonstrate that this particular operator reduced promotional spending when confronted with increases in gaming tax rates. These results suggest that legislators have a cause for concern when considering increases in a state’s gaming tax rate. This study confirms that operators may reduce their effort to attract gaming volume in response to gaming tax increases, and opens the door to questioning whether their business volume is diverted elsewhere to generate gaming revenues and the resulting gaming tax receipts

    Extremely narrow spectrum of GRB110920A: further evidence for localised, subphotospheric dissipation

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    Much evidence points towards that the photosphere in the relativistic outflow in GRBs plays an important role in shaping the observed MeV spectrum. However, it is unclear whether the spectrum is fully produced by the photosphere or whether a substantial part of the spectrum is added by processes far above the photosphere. Here we make a detailed study of the γ−\gamma-ray emission from single pulse GRB110920A which has a spectrum that becomes extremely narrow towards the end of the burst. We show that the emission can be interpreted as Comptonisation of thermal photons by cold electrons in an unmagnetised outflow at an optical depth of τ∼20\tau \sim 20. The electrons receive their energy by a local dissipation occurring close to the saturation radius. The main spectral component of GRB110920A and its evolution is thus, in this interpretation, fully explained by the emission from the photosphere including localised dissipation at high optical depths.Comment: 14 pages, 11 figures, accepted to MNRA

    Benefits and challenges to productive use of off-grid rural electrification: The case of mini-hydropower in Bulongwa-Tanzania

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    This paper presents a case study of a minigrid powered by a small hydro plant in the southern highlands of Tanzania. The approach was chosen to provide in-depth understanding on benefits and challenges facing a rural minigrid. The case focuses on productive use; i.e. electricity as a direct input to the production of goods or provision of services. The study applies an interdisciplinary approach consisting of a mix of qualitative and quantitative methods, which included stakeholder and user interviews and measurements of output power and water flow. The analysis shows that certain entrepreneurial activities emerged as an outcome of electricity access thru the minigrid; barber shops, welding machines, mobile phone charging, salons, photo copy, and lighting business centres. Major challenges are related to the initial set up of the mini-hydro power plant, i.e. to only service the hospital, as the idea and need for building a minigrid developed much later. A tentative conclusion is that subsidized electricity will not promote rural businesses unless other criteria are met. Moreover, the minigrid faced a number of technical problems partly because of lack of adequate technical resources such as technicians and spare parts but also from the poor-planning and non-saving culture. The study concludes that the minigrid has led to productive uses that are found elsewhere in grid-connected rural communities. The finite supply of energy however means that there are restrictions using electricity for certain productive use – there is a load shedding schedule in place for some of the power intensive machines - due to overload caused by the load and large number of connections. Finally, there is apparent room for improvement not the least regarding the tariffs, which do not reflect market price and hence may affect the sustainability of the system

    Phase composition and transformations in magnetron-sputtered (Al,V)2O3 coatings

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    Coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited by pulsed DC reactive sputter deposition on Si(100) at a temperature of 550 {\deg}C. XRD showed three different crystal structures depending on V-metal fraction in the coating: {\alpha}-V2O3 rhombohedral structure for 100 at.% V, a defect spinel structure for the intermediate region, 63 - 42 at.% V. At lower V-content, 18 and 7 at.%, a gamma-alumina-like solid solution was observed, shifted to larger d-spacing compared to pure {\gamma}-Al2O3. The microstructure changes from large columnar faceted grains for {\alpha}-V2O3 to smaller equiaxed grains when lowering the vanadium content toward pure {\gamma}-Al2O3. Annealing in air resulted in formation of V2O5 crystals on the surface of the coating after annealing to 500 {\deg}C for 42 at.% V and 700 {\deg}C for 18 at.% V metal fraction respectively. The highest thermal stability was shown for pure {\gamma}-Al2O3-coating, which transformed to {\alpha}-Al2O3 after annealing to 1100{\deg} C. Highest hardness was observed for the Al-rich oxides, ~24 GPa. The latter decreased with increasing V-content, larger than 7 at.% V metal fraction. The measured hardness after annealing in air decreased in conjunction with the onset of further oxidation of the coatings

    Is There a Relationship between Abdominal Aortic Aneurysms and Alpha1-antitrypsin Deficiency (PiZ)?

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    AbstractObjective:to determine if the frequency of α1AT deficiency (PiZ) is increased in patients with abdominal aortic aneurysm (AAA), and, to investigate whether aneurysmal stiffness and other clinical characteristics differ in AAA patients with and without α1AT deficiency.Methods:we identified α1AT-deficient individuals by a monoclonal-antibody ELISA technique, in 102 consecutive patients with AAA. Positive ELISA samples were further phenotyped by isoelectric focusing to differentiate between the heterozygosity (PiZ) and homozygosity (PiZZ) state. Aneurysmal diameter and stiffness was measured using echotracking sonography and blood pressure measurements.Results:the frequency of heterozygous α1AT deficiency (PiZ) in patients with AAA was similar to that in the general population (6.8% and 4.7%, respectively,p>0.3). The frequency of popliteal and femoral aneurysm was similar in male PiZ-carriers and non-carriers with AAA, as were age at diagnosis of AAA, aneurysmal diameter, aneurysmal stiffness, and presence of factors that may be associated with AAA (i.e. smoking, hypertension, diabetes mellitus, and family history of AAA). Occurrence of ischaemic heart disease was more frequent in male non-PiZ-carriers than in male PiZ-carriers with AAA (p=0.03).Conclusions:the frequency of α1AT deficiency (PiZ) was not increased in our series of patients with AAA and patients in whom the two disorders coexisted did not appear to have different clinical characteristics except for the lower occurrence of ischaemic heart disease among the PiZ-carriers

    Efficient management of virtualized information-centric networks

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    The Internet has rapidly evolved from a network, connecting a couple of dozens of computers, to a network containing billions of devices. Furthermore, the current Internet is mostly used to deliver complex services with increasingly stringent Quality of Service (QoS) requirements. However, the underlying network model has remained the same, making the Internet not well suited to optimally support the current user trends and services. Currently, a lot of effort is being made in the area of network virtualization and Information-Centric Networking (ICN) to support the evolution towards the QoS constraint distribution of large amounts of information. Even though both directions offer a lot of opportunities, multiple important challenges have to be faced when managing the placement of content inside the network and guaranteeing delivery efficiency. These challenges are further increased when a combination of both trends is considered. This paper gives an overview of these challenges and how this PhD will deal with the mutual influences of network virtualization and ICN in an efficient way

    Super congruences and Euler numbers

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    Let p>3p>3 be a prime. We prove that ∑k=0p−1(2kk)/2k=(−1)(p−1)/2−p2Ep−3(modp3),\sum_{k=0}^{p-1}\binom{2k}{k}/2^k=(-1)^{(p-1)/2}-p^2E_{p-3} (mod p^3), ∑k=1(p−1)/2(2kk)/k=(−1)(p+1)/28/3∗pEp−3(modp2),\sum_{k=1}^{(p-1)/2}\binom{2k}{k}/k=(-1)^{(p+1)/2}8/3*pE_{p-3} (mod p^2), ∑k=0(p−1)/2(2kk)2/16k=(−1)(p−1)/2+p2Ep−3(modp3)\sum_{k=0}^{(p-1)/2}\binom{2k}{k}^2/16^k=(-1)^{(p-1)/2}+p^2E_{p-3} (mod p^3), where E_0,E_1,E_2,... are Euler numbers. Our new approach is of combinatorial nature. We also formulate many conjectures concerning super congruences and relate most of them to Euler numbers or Bernoulli numbers. Motivated by our investigation of super congruences, we also raise a conjecture on 7 new series for π2\pi^2, π−2\pi^{-2} and the constant K:=∑k>0(k/3)/k2K:=\sum_{k>0}(k/3)/k^2 (with (-) the Jacobi symbol), two of which are ∑k=1∞(10k−3)8k/(k3(2kk)2(3kk))=π2/2\sum_{k=1}^\infty(10k-3)8^k/(k^3\binom{2k}{k}^2\binom{3k}{k})=\pi^2/2 and \sum_{k>0}(15k-4)(-27)^{k-1}/(k^3\binom{2k}{k}^2\binom{3k}k)=K.$
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