387 research outputs found
On-Site Wireless Power Generation
Conventional wireless power transfer systems consist of a microwave power
generator and a microwave power receiver separated by some distance. To realize
efficient power transfer, the system is typically brought to resonance, and the
coupled-antenna mode is optimized to reduce radiation into the surrounding
space. In this scheme, any modification of the receiver position or of its
electromagnetic properties results in the necessity of dynamically tuning the
whole system to restore the resonant matching condition. It implies poor
robustness to the receiver location and load impedance, as well as additional
energy consumption in the control network. In this study, we introduce a new
paradigm for wireless power delivery based on which the whole system, including
transmitter and receiver and the space in between, forms a unified microwave
power generator. In our proposed scenario the load itself becomes part of the
generator. Microwave oscillations are created directly at the receiver
location, eliminating the need for dynamical tuning of the system within the
range of the self-oscillation regime. The proposed concept has relevant
connections with the recent interest in parity-time symmetric systems, in which
balanced loss and gain distributions enable unusual electromagnetic responses.Comment: 10 pages, 13 figure
Nonlinear Control of Tunneling Through an Epsilon-Near-Zero Channel
The epsilon-near-zero (ENZ) tunneling phenomenon allows full transmission of
waves through a narrow channel even in the presence of a strong geometric
mismatch. Here we experimentally demonstrate nonlinear control of the ENZ
tunneling by an external field, as well as self-modulation of the transmission
resonance due to the incident wave. Using a waveguide section near cut-off
frequency as the ENZ system, we introduce a diode with tunable and nonlinear
capacitance to demonstrate both of these effects. Our results confirm earlier
theoretical ideas on using an ENZ channel for dielectric sensing, and their
potential applications for tunable slow-light structures
Computational Model of Artificial Neural Networks and its Applications in Data Mining
Data remain a very important ingredient required by any organization to make informed decision as it affects operations. Companies have been collecting data from various sources over the decades bringing about a very large volume of data warehouse. Unfortunately, most organizations build databases which are redundant and never used for any meaningful thing. While few companies use the data collected in their databases when taking strategic decisions others barely do same. However, for an organization to immensely derive benefits from the massive data warehouse, there is the need for an effective and efficient means of analysing the data with a view to extracting meaningful knowledge that is sufficient to achieve organizational goal. To achieve this, Artificial Neural Network (ANN) technique through the concept known as data mining is presented. The paper reviewed artificial neural network technique for data mining, examines the computational model behind this technique and analysed its use and application as a predicting or forecasting tool. Results shows that ANN’ has capability in data management, analysis and able to provide desirable knowledge for management decision making processes. It is therefore recommended that data mining tools like ANN and others be applied to organization’s databases which hitherto have not been minned in order to provide management with intelligence for decision makin
Tensile and Hardness Property Evaluation of Kaolin- Sisal Fibre- Epoxy Composite
In this work, the tensile and hardness properties of Kaolin- sisal fibre- epoxy composite were evaluated using standard methods. Epoxy type 3354A with its hardener was mixed in the ratio 2:1. Calcined kaolin particle with average size of 35µm and 3-4mm sisal fibre were added to the epoxy matrix during the composite manufacture in a proportion of: 60/40 wt %, 60/30/10 wt %, 60/20/20 wt %, 60/10/30 wt % for matrix, fibre and Kaolin respectively. The green mixtures were poured into aluminum mould and left for 24 hrs to cure. The results showed that the addition of kaolin and sisal fibre affected mechanical properties of the epoxy resin. The maximum strain observed for each specimen after tensile tests were as follows: 12% for specimen A; 12% for specimen B; 3.9% for specimen C; 11.5% for specimen D and 6% for specimen E. The Shore D hardness values were as follows: 79.1 for specimen A (control); 55.68 for specimen B; 42.82 for specimen C; 78.7 for specimen D and 81.34 for specimen E. The hardness values was reduced from 55.68 to 42.83 and increased to 81.34. Specifically, the tensile and hardness properties increased proportionately with the fibre quantity and inversely proportional to the kaolin content. These are attributed to the level of bonding strengths between the fibre-matrix-particulate interfacial adhesions.http://dx.doi.org/10.4314/njt.v34i4.1
The effect of funding strategy on the lending patterns of banks in Ghana
This article examines the effect of funding strategy on the lending patterns of banks in Ghana. We employ a panel dataset of banks from 2005 to 2011, to analyse the impact of funding sources on three sets of lending patterns employed by banks: Primary, secondary and tertiary economic sectors. The result shows that banks in Ghana use internally generated funds to finance loans to the primary and secondary sectors of the economy. In addition, our findings suggest that bank lending to the tertiary sector of the economy is significantly more sensitive to wholesale funding than to deposit and internally generated funds. The overall implication of this finding is that the bank funding structure needs to be considered in addition to the traditional bank-specific indicators when assessing banks’ ability to finance economic activities.Keywords: Africa, developing country, funding sources, Ghana, lending pattern
Management of Family’s Finances and Family Wholeness: Evidence from Ilishan-Remo Community, Ogun State, Nigeria.
This paper examined the extent to which couples are involved in the management of their family’s finances: Evidence from Ilishan-Remo Community. The study was driven by the fact that finance is one of the major complex factors leading to suspicion, disagreements, fighting, or worst still divorce in the home and many families have been shattered by lack of/ineffective management of it because of their misconception about the family’s financial officer. As a result of this, many questions have been raised: should couples maintain joint account? who manages the family’s finance for family wholeness? Could ineffective management of the family’s finance lead to couples unfaithfulness? In order to achieve the set objective(s) and answer the research questions, an explanatory survey research design was adopted. The study utilized the primary source of data by administering 80 questionnaires out of which 71 were duly completed and returned. Secondary data sources were consulted as well. The data was analyzed using descriptive statistics and the result showed that although the husband is seen as the head of the family, decisions concerning the family (including management of family finances) should not be taken solely by him, but by both parties. If the family finance is not managed in an effective and efficient manner, it could lead to couples unfaithfulness to one another. Therefore, the husband or wife should not see the money which he or she earns as his or her personal money but the family’s finance/income which should be pooled together based on their agreement and also spent together. However, they should not spend all their earnings no matter how little but, save some for the rainy day. This can only be achieved by proper planning/ budgeting. Keywords: family finance; financial management; family wholeness; planning and budgetin
Schrodinger's Hat: Electromagnetic, acoustic and quantum amplifiers via transformation optics
The advent of transformation optics and metamaterials has made possible
devices producing extreme effects on wave propagation. Here we give theoretical
designs for devices, Schr\"odinger hats, acting as invisible concentrators of
waves. These exist for any wave phenomenon modeled by either the Helmholtz or
Schr\"odinger equations, e.g., polarized waves in EM, pressure waves in
acoustics and matter waves in QM, and occupy one part of a parameter space
continuum of wave-manipulating structures which also contains standard
transformation optics based cloaks, resonant cloaks and cloaked sensors. For EM
and acoustic Schr\"odinger hats, the resulting centralized wave is a localized
excitation. In QM, the result is a new charged quasiparticle, a \emph{quasmon},
which causes conditional probabilistic illusions. We discuss possible solid
state implementations.Comment: 36 pages, 3 figure
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