2,172 research outputs found

    Design a high gain UWB mimo uniplanar monopole antenna with FSS array for metallic object microwave imaging

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    Ultra-wideband (UMB) system plays an important role in microwave imaging (MWI) applications due to its broad bandwidth, non-ionizing radiation, and cost-efficiency. this study involves the design and development phases for the optimum solution of UMB antenna's issues. In the design phase, a compact uniplanar hexagon UMB monopole antenna with a coplanar waveguide (CPW) feed is designed. The proposed UMB antenna has an oscillate impedance (za) of 50Ω. A meander-line notch filter is loaded on the designed antenna that achieves a high rejection (S11=-1.75 dB) at the band of 3.0 GHz for 5G mid-band. A T-strip is inserted between the two proposed MIMO antennas to improve the isolation. Moreover, the smallest uniplanar UWB frequency selective surface (FSS) unit cell size (0.095λx0.095λ) is miniaturized on the FR4 substrate. The simulations are compared with the equivalent circuit models of the proposed solutions, then validate with the measurement results. In the development phase, the hexagonal monopole MIMO antenna, The CPW feed, the isolation T-strip, and the 3 x 7 FSS (IMAF) achieves a bandwidth of 3-11.7 GHz, unidirectional radiation patterns, mutual coupling (S21 about -27 dB) and gain (6-8.5 dBi), and it better than the existing antennas of 3.1-10.6 GHz, _20 dB, and 5.5 dBi, respectively. Additionally, the baggage-scanner scheme is developed as a case study to evaluate the IMAF is 55% higher than that of the MIMO antenna without an FSS array. Thus, the proposed IMAF detects the smallest (0.5 x 2 cm2 ) metallic object with a location accuracy of ¥ o.5 cm compared with the recent simulation study of (0.6 x 0.h cm2 and ±1.1 cm, respectively). A good agreement is observed between the simulated and measured images of the MWI. Consequently, the IMAF is proved to be applicable as part of the detection system for low-cost and non-intricate baggage-scanner imaging to detect metallic objects

    Prehistory to 1250: Languages

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    The Hemic group includes the Egyptian and Coptic languages, the Libyan and Barbarian languages, the Koshtia languages, and the languages of the original inhabitants of the eastern part of Africa. [excerpt

    Botanical insecticides prescription for fish pest control and infestation free protein yield

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    The dry powders of four local species namely Piper guineense Schum and Thonn, Aframomum melegueta Schum, Zingiber officinale Rose; Capsicum annum Miller at three concentrations of 15g, 20g and 25g.kg were evaluated for their insecticidal effects against the larval of the dried fish weevil Demestes maculates Degeer. All the four species showed some effectiveness with P. guineense given a 100% mortality at the end of 72 hours at the three concentrations. The other species though gave less mortality were able to slow down the rate of development of the larvae to the adult siz

    An Evaluation of the Wisconsin Breast Cancer Dataset using Ensemble Classifiers and RFE Feature Selection Technique

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    Breast cancer represents one of the deadliest diseases that records a high number of death rate annually. It is the most common type of cancer and the main cause of death among women worldwide. Machine learning (ML) approach is an effective way to classify data, especially in medical field. It is widely used for classification and analysis to make decisions. In this paper, a performance comparison between two ensemble ML classifiers: Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) on the Wisconsin Breast Cancer Dataset (WBCD) is conducted. The main objective of this study is to assess the correctness of the classifiers with respect to their efficiency and effectiveness in classifying the dataset. This was done by utilizing all and reduced features of the dataset that were generated with Recursive Feature Elimination (RFE) feature selection technique. Four metrics were used in the study: Accuracy, Precision, Recall and F1-Score to evaluate the classifiers. All experiments were executed within Anaconda Environment with Jupyter Notebook and conducted using Python programming language. Experimental result shows that XGBoost with 5 reduced feature using RFE feature selection technique gives the highest accuracy (99.02%) with lowest error rate

    Energy saving through load balancing of 3-wire loads

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    In this paper, static var compensators (SVCs) and many load compensation techniques are reviewed. A continuously and linearly controlled compensating susceptance is devised from a switched capacitor bank and a switched reactor bank. The switched capacitor bank is built of four binary weighted thyristor switched capacitors, while the switched reactor bank is built of three binary weighted thyristor switched reactors. Although few switched capacitors and reactor are used, their binary weighted values beside their control scheme make them respond as a continuously and linearly controlled reactive device in capacitive and inductive modes of operation. A load balancing system is constructed of three identical devised compensating susceptances connected in delta-form. It is designed for balancing an 11 kV 50 Hz distribution station. The proposed system is designed and tested on PSpice which is a computer program equivalent in performance to real hardware design. The simulation results of the proposed system have showed significant treatment of severe imbalance conditions

    Day case surgery in Nigeria

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    Patient care in Nigeria is mostly government funded, from primary to tertiary levels, with little contribution from private sector and non-governmental organizations. Healthcare provision has become more complex and expensive partly due to increasing population, aging, and frequent cancellations of electives, but also due to the increasing emergence of new diseases, as well as shrinkage of resources in many developing countries like Nigeria, resulting from recent economic downturn, and political instability. Therefore, it is important to introduce and popularize the concept of day case surgery, as this may help hospitals and healthcare providers to streamline resources by reducing length of hospital stay, decreasing morbidity and mortality, and providing valuable bed services to emergencies. It also helps to reduce time lost away from work and indirectly helps to decrease loss of revenue for the individual and state. Many hospitals in Nigeria provide day care services with patients admitted to the general surgical wards, and no dedicated day surgery units (DSUs), as currently practised in developed countries. DSUs are the best way to achieve results and so it is important for all to embrace this concept in order to improve healthcare delivery to the rapidly expanding populations. A systematic search of the current published literature was carried out to look for articles related to day case surgery (day care or day surgery) in Nigeria and to examine some published articles in relation to the surgical subspecialities, with a view to highlighting current practice in Nigeria and how it conforms to ideal practice elsewhere. Recommendations and suggestions are made on how to implement and popularize this concept in our hospitals
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