Design and simulation of cross-block structured radar absorbing metamaterial based on carbonyl iron powder composite

This paper reports the design and simulation of a three layered cross-block structured radar absorbing metamaterial (RAMM). The effective electromagnetic parameters of the designed structure are highly dependent on its geometric dimensions, subsequently behaving as a metamaterial. COMSOL Multiphysics simulation software was used to analyze the frequency dependent absorption response of the designed RAMM. The input impedance of multilayered absorber and strong fluctuation theory equations are used to theoretically verify the absorption response of the RAMM. The simulated result showed that the reflectivity of the RAMM is below -10dB from 4.2 – 18.0 GHz frequency band with absorber thickness of 4.2mm. The calculated reflectivity result is in close agreement with the simulated result, thus confirming the validity of the design. The operational bandwidth to thickness ratio of this RAMM was found to be 13.029 making it better than the recently reported one with a value of 9.745 and thus contributing significantly in overcoming the contradicting demand of broadband and thin thickness.Keywords: Bandwidth, COMSOL Multiphysics, Metamaterial, Radar Absorbing Metamaterial, Reflectivit

Impact of internally displaced persons on forest and vegetation of Jere LGA, Borno State, Nigeria

Deforestation is described as changes in the structure and composition of an area of forest after there has been some form of human intervention such as firewood, charcoal and logging. The study examined impact of internally displaced persons (IDPs) on forest and vegetation cover of Jere L.G.A. of Borno State, Nigeria. The objectives of the study were to determine the extent of impact of deforestation and depletion of vegetation cover caused by displaced persons to forest of Jere L.G.A. and also identifies the socio-economic needs of the displaced persons in camps. Data were collected from both primary and secondary sources. Primary data were generated through field observation and focused group discussion with displaced persons, while the secondary data was obtained from relevant available literature. Findings revealed that about 12 square kilometers of forest and vegetation cover were destroyed by displaced persons. The Findings also revealed that displaced persons engaged in cutting of trees for shelter, firewood, charcoal and debarking trees for medicinal purpose to earn money. The study revealed displaced persons conditioned in camps are deplorable far from the ideal situation. The study concluded that environmental impact assessment should be incorporated in the strategies for displaced persons welfare before their arrival. The study recommended that host governments, humanitarian agencies and NGOs should support the living conditions of displaced persons through socio-economic, education, skill and vocational training development that promotes lifelong learning opportunities.Keywords: Displaced persons, Deforestation, Vegetation, Firewood and Charcoa

Implications of the Top Quark Mass Measurement for the CKM Parameters, xsx_s and CP Asymmetries

Motivated by the recent determination of the top quark mass by the CDF collaboration, \mt =174 \pm 10 ^{+13}_{-12} GeV, we review and update the constraints on the parameters of the quark flavour mixing matrix $V_{CKM}$ in the standard model. In performing our fits, we use inputs from the measurements of the following quantities: (i) \abseps, the CP-violating parameter in $K$ decays, (ii) \delmd, the mass difference due to the \bdbdbar\ mixing, (iii) the matrix elements \absvcb and \absvub, and (iv) $B$-hadron lifetimes. We find that the allowed region of the unitarity triangle is very large, mostly due to theoretical uncertainties. (This emphasizes the importance of measurements of CP-violating rate asymmetries in the $B$ system.) Nevertheless, the present data do somewhat restrict the allowed values of the coupling constant product $f_{B_d}\sqrt{\hat{B}_{B_d}}$ and the renormalization-scale invariant bag constant $\hat{B}_K$. With the updated CKM matrix we present the currently-allowed range of the ratio $\vert V_{td}/V_{ts} \vert$, as well as the standard model predictions for the \bsbsbar\ mixing parameter \xs and the quantities $\sin 2\alpha$, $\sin 2\beta$ and $\sin^2\gamma$, which characterize the CP-asymmetries in $B$-decays. The ALEPH collaboration has recently reported a significant improvement on the lower limit on the \bs-\bsb mass difference, $\Delta M_s/\Delta M_d > 11.3$ (95\% C.L.). This has interesting consequences for the CKM parameters which are also worked out. NOTE: this is a revised and updated version of our previous paper.Comment: LaTeX, 27 pages, 16 uuencoded figures (enclosed), CERN-TH.7398/94, UdeM-GPP-TH-94-0

On the need for cultural sensitivity in digital wellbeing tools and messages: A UK-China comparison

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2020. The excessive and obsessive use of the internet and digital technologies, known as Digital Addiction (DA), is becoming a social issue. Given that it inherently involves the use of technological devices this provides the opportunity to deliver interactive, intelligent prevention and intervention strategies in real-time. However, for any large-scale, multi-national prevention campaign to be optimised cultural differences within the target population must be considered. This study aimed to contribute towards this literature by exploring cultural differences in the acceptance of DA prevention messages in the UK vs China. An initial series of exploratory interviews were conducted with a sample within the UK to determine what strategies may be used to address the overuse of digital devices. These interviews were subjected to content analysis, which was then used as the basis for an online survey that was disseminated throughout the UK and China. A total of 373 useable surveys were returned. There were several statistically significant differences in preferences over how an intervention system should operate. UK participants wished for the system to be easily under their control, whilst behaving largely autonomously when needed, and to also be transparent as to why a message had been triggered. Chinese participants, on the other hand, were less likely to state a preference for such a high degree of control over any such system. Overall, the preferred implementation of such systems does appear to vary between the UK and China, suggesting that any future prevention and intervention strategies take cultural dimensions into consideration

Real time hand gesture recognition for computer interaction

Hand gesture recognition is a natural and intuitive way to interact with the computer, since interactions with the computer can be increased through multidimensional use of hand gestures as compare to other input methods. The purpose of this paper is to explore three different techniques for HGR (hand gesture recognition) using finger tips detection. A new approach called 'Curvature of Perimeter' is presented with its application as a virtual mouse. The system presented, uses only a webcam and algorithms which are developed using computer vision, image and the video processing toolboxes of Matlab. © 2014 IEEE

Heuristic Multi-Agent Control for Energy Management of Microgrids with Distributed Energy Sources

The increased integration of distributed Renewable Energy Sources (RESs) and adoption of Electric Vehicles (EVs) require appropriate control and management of energy sources and EV charging. This becomes critical at the distribution system level, especially at a microgrid (MG) level. This control is required not only to mitigate the negative impacts of intermittent generation from RESs but also to make better use of available energy, reduce carbon footprint, maximize the overall profit of microgrid and increase energy autonomy by effective utilization of battery storage. This paper proposes a heuristic multi-agent based decentralized energy management approach for grid-connected MG. The MG comprises of active (controlled) and passive (uncontrolled) electrical loads, a photovoltaic (PV) system, battery energy storage system (BESS) and a charging post for electric vehicles. The proposed approach is aimed at optimizing the use of local energy generation from photovoltaic and smart energy utilization to serve electrical loads and EV as well as maximizing MG profit. The aim of the energy management is to supply local consumption at minimum cost and less dependency on the main grid supply. Utilizing energy available from RESs (PV and BESS), customers satisfaction (fulfilling local demand), considering uncertainty of renewable generation and load consumption and also taking into account technical constraint are the main strengths of the presented framework. Performance of the proposed algorithm is investigated under different operating conditions and its efficacy is verified

Charged bottomonium-like structures Zb(10610)Z_b(10610) and Zb(10650)Z_b(10650)

The observation of two charged bottomonium-like structures $Z_b(10610)$ and $Z_b(10650)$ has stimulated extensive studies of the properties of $Z_b(10610)$ and $Z_b(10650)$. In this talk, we briefly introduce the research status of $Z_b(10610)$ and $Z_b(10650)$ combined with our theoretical progress.Comment: 6 pages, 1 table, 5 figures. Plenary talk given at the international conference The Fifth Asia-Pacific Conference on Few-Body Systems in Physics 2011 (APFB2011), Seoul, Republic of Korea, 22-26 August 201

Perceptions and misperceptions of smartphone use: Applying the social norms approach

The social norms approach is an established technique to bring about behaviour change through challenging misperceptions of peer behaviour. This approach is limited by a reliance on self-report and a lack of interactivity with the target population. At the same time, excessive use of digital devices, known as digital addiction, has been recognized as an emergent issue. There is potential to apply the social norms approach to digital addiction and, in doing so, address some of the limitations of the social norms field. In this study, we trialled a social norms intervention with a sample of smartphone users (n = 94) recruited from the users of a commercial app designed to empower individuals to reduce their device usage. Our results indicate that most of the sample overestimated peer use of smartphone apps, demonstrating the existence of misperceptions relating to smartphone use. Such misperceptions are the basis for the social norms approach. We also document the discrepancy between self-report and smartphone usage data as recorded through data collected directly from the device. The potential for the application of the social norms approach and directions for future research are discussed

Tumeur stromale du mésentère: une cause inhabituelle d’une masse abdominale

Les tumeurs stromales gastro-intestinales (GIST) sont les tumeurs mésenchymateuses les plus fréquentes du tractus digestif. Elles représentent une entité nosologique individualisée depuis la découverte de l'expression quasi-constante de la protéine c-Kit détectée par la coloration immunohistochimique de l'antigène CD117. Des tumeurs avec les mêmes caractéristiques morphologiques et immuno-phénotypiques peuvent rarement apparaître en dehors du tractus gastro-intestinal. Nous rapportons le cas d'une jeune patiente de 34 ans présentant une masse tumorale mésentérique se révélant être de nature stromale sans aucun contact avec la paroi intestinale. Il s'agit d'une localisation très rare des tumeurs stromales à laquelle il faut penser en préopératoire afin d'avoir une conduite thérapeutique adaptée et efficace

Remarks on self-interaction correction to black hole radiation

In the work [P. Kraus and F. Wilczek, \textit{Self-interaction correction to black hole radiation, Nucl. Phys.} B433 (1995) 403], it has been pointed out that the self-gravitation interaction would modify the black hole radiation so that it is no longer thermal, where it is, however, corrected in an approximate way and therefore is not established its relationship with the underlying unitary theory in quantum theory. In this paper, we revisit the self-gravitation interaction to Hawking radiation of the general spherically symmetric black hole, and find that the precisely derived spectrum is not only deviated from the purely thermal spectrum, but most importantly, is related to the change of the Bekenstein-Hawking entropy and consistent with an underlying unitary theory.Comment: 14 page