278 research outputs found

    Novel Dual Band Frequency Selective Surface and its Applications on the Gain Improvements of Compact UWB Monopole Antenna

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    In this work, a highly directional ultra-wideband (UWB) microstrip patch antenna as a single-element is suggested. The proposed antenna’s gain is enhanced with a novel dual-band frequency selective surface (FSS) placed beneath it. The FSS design has a hexagonal structure with meander line inductances and a capacitance-like structure connecting all of the corners to the middle. There is no metallic layer on the other side of the substrate, which shows transmission zeros at 4.95 GHz and 12.7 GHz, and a modified U-shaped monopole antenna is developed. First, the performance characteristics of the antenna and FSS are analyzed from the simulation results, and they are validated experimentally after fabrication, followed by measurement. The compact configuration comprises an antenna loaded with the proposed FSS results S11 less than -10 dB from 3.15 GHz to 22.65 GHz, covering the UWB band together with the X, Ku-band with a bandwidth of 19.5 GHz (151.16% FBW). The antenna’s overall physical dimensions would be 38.8 mm×38.8 mm×25.2 mm (0.407λo×0.407λo×0.265λo), with λo denoting the lowest frequency’s free-space wavelength. The FSS loading results in a 9.9 dBi maximum gain at 10 GHz. The antenna’s small size increases bandwidth, and its high peak gain makes it ideal for use in real-time applications

    Compact UWB Monopole Antenna with Tunable Dual Band Notched Characteristics for WiMAX and WLAN Applications

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    The present work shows a planar compact ultra-wideband (UWB) monopole antenna with controllable dualband-notch frequencies at 3.3 GHz for WiMAX and 5 GHz for WLAN. In the proposed antenna, the lower notchband (at a frequency of 3.3 GHz) is made by cutting a thin horizontal strip on top of the radiating patch. The uppernotch band (at a frequency of 5 GHz) is made by putting two narrow parasitic strips in the shape of an “I” oneither side of the radiating patch. The incorporation of three varactor diodes between the radiating patch and three metallic strips provides the flexibility of adjusting the notch frequencies. The notch band tunability between 3.15 GHz and 3.69 GHz and between 4.93 GHz and 5.59 GHz, respectively, is achieved by changing the bias voltageof the varactor diode between 0 V and 30 V. The gain and efficiency characteristics of the designed antenna alsoexhibit band rejection at the respective notch frequencies. The design principle is validated by fabricating andmeasuring a prototype of the proposed dual-band, notched UWB antenna. For three different bias voltages of thevaractor, the simulated and experimental findings are in reasonable agreement. The proposed works demonstratebetter-notch characteristics as compared with other reported works over the UWB rang

    Infected gap nonunion of fractures proximal humerus in adolescent: an outcome of 12 cases

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    Background: There is little data about the risk factors, demographics, and prognosis for nonunions in children. Previous literature has reviewed time periods when contemporary techniques of internal fixation and management of open injuries had not been available. Infected gap nonunion of proximal 1/3 humerus in adolescent is not much reported the in literature. The purpose of our study was to evaluate the outcome of infected gap nonunion in 12 cases of adolescent treated by debridement and fibular graft and plating.Methods: This study was conducted between 2009 to 2015, 12 cases of Infected gap nonunion of fractures proximal humerus was included in our study. Each child was followed up minimum for 12 months.  Although non unions in the pediatric population are rare, these data underscore the importance of careful evaluation and treatment of these fractures at risk for nonunion.Results: In our series of 12 cases of infected nonunion of fracture humerus which were treated by bone grafting using fibula strut graft and plating resulted 99% union rate. The rate of union is depending on thorough debridement and fixation along with bone grafting.Conclusions: Nonunion of pediatric fractures is a rare complication. Most studies on developing pediatric nonunions describe specific fractures that are particularly susceptible to nonunion and malunion, nonunion of humeral lateral condyle and open tibia fractures have received the most attention. Reports of nonunion among pediatric long bone fractures are rare, being either case reports or isolated entities in a larger series of predominantly adult fractures. Fibula is a popular substitute for this method because of its easy accessibility and minimal donor site morbidity

    Laryngeal Neuroendocrine Tumor - An Atypical Presentation

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    Neuroendocrine tumors of the larynx are the most common non-epidermoid tumors of the larynx and comprise less than 1% of the laryngeal tumors. Most of the symptoms and presentation mimic any usual laryngeal malignancy making the diagnosis difficult. Here, we report a case of laryngeal neuroendocrine carcinoma that was managed with total laryngectomy

    Investigation of Hazardous Materials in Firecrackers using LIBS Coupled with a Chemometric Method and FTIR Spectroscopy

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    This article reports the detection and quantification of toxic constituents in firecrackers using LIBS coupled with PCA and FTIR. Spectral signatures of lethal elements along with other elements and electronic bands of Cyanide, AlO, BaO, and CaO are seen in their LIBS spectra which confirms the presence of inorganic and organic compound in the fireworks. The concentration of each constituent/element is determined using the CF-LIBS method and results are compared with ICP-OES results. The concentration of Al is in adequate amount except S4 (b). Li and Ba are present in all samples with maximum amount in S4 (b) and S3 respectively. Molecular stretching of SO4-, C4 H8 - , CuCl- , CO3 - , and NO3 - are observed in the FTIR spectra of the samples. The combined results of LIBS and FTIR recommends the presence of BaNO3 , LiCO3 , SrCO3 , Al-chip, and charcoal in the firecrackers. To discriminate various firecrackers, PCA of the LIBS data is performed. The results show that S3 and S4 (b) are more harmful as they contain higher concentration the compounds of Al, Ba, Li, Sr i.e BaNO3 , LiCO3 , SrCO3 , (Cu3 As2 O3 Cu(C2 H3 O2 )2 )

    Socio-economic upliftment of farmers through model irrigated village approach in East Champaran (Bihar), India: A case study

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    In India, the precious freshwater resources are becoming scarcer due to the climate change effect coupled with their inappropriate planning and management at the field level. Development of water resources and sensitization of farming community/irrigators towards effective utilization of these resources is need of the hour and it is one of the most important factors in conservation and preservation water resources for future requirements. This case study has highlighted the direct and indirect benefits derived by implementation of National Innovations on Climate Resilient Agriculture (NICRA) scheme in Nawada, a village of the district East Champaran in Bihar state initiated by Krishi Vigyan Kendra, Piprakothi, East Champaran under Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar. Two groups of farmers of the village was chosen to evaluate the benefits derived from this scheme. Under this scheme, tube-wells were developed to facilitate assured irrigation. This study revealed that the total savings of approximate Rs.10,000 ($140) per hectare to irrigate wheat crop three times in Rabi season was achieved over conventional irrigation system. This scheme has also resulted in other intangible benefits which included a reduction in pollution, an increase in the number of crops- rabi , kharif and zaid  seasons and adequate time to carryout out other farm operations

    Low carbon warehouse management under cap-and-trade policy

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    © 2016 Elsevier Ltd Green warehouse management plays a significant part in developing a carbon efficient supply chain. This research examines the behaviour change in warehouse management decisions under the cap-and-trade emission policy and explores the role of green technology investment in managing the trade-offs between the economic and environment performances of warehousing operations. This study analyses the optimal decisions in warehouse management and technology investment under the cap-and-trade emissions policy to assist the practitioners in making efficient decisions. Moreover, this study also investigates the effect of initial carbon emission allowance and transaction costs of the unit carbon emission trading with the outside market, on the economic and environment performances of warehousing operations. The findings of this study provide useful insights in greening the warehousing operations and reducing the carbon emissions

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
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