41 research outputs found

    mmWave Four-Element MIMO Antenna for Future 5G Systems

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    This paper presents an S-shape four-port Multiple Input Multiple Output (MIMO) wideband mmWave antenna with bandwidth of 25 GHz to 39 GHz. The antenna is designed on 0.254 mm ultra-thin RO5880 with permittivity of 2.3. The dimensions of proposed S-shape antenna are 10 12 mm for single element and 24 24 mm for four-port MIMO configuration. A decoupling network is introduced to further compress mutual coupling among MIMO elements. The peak gain achieved is 7.1 dBi and MIMO assembly delivers diversity scheme. The proposed MIMO antenna is fabricated, and simulated results are found to be in excellent agreement with simulations. Through the results obtained, the proposed MIMO antenna system can be considered as a potential candidate for future mmWave devices.This project has received funding from Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant 801538

    A Four Element mm-Wave MIMO Antenna System with Wide-Band and High Isolation Characteristics for 5G Applications

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    In this article, we propose a light weight, low profile Multiple Input Multiple Output (MIMO) antenna system for compact 5th Generation (5G) mmwave devices. Using a RO5880 substrate that is incredibly thin, the suggested antenna is made up of circular rings stacked vertically and horizontally on top of one another. The single element antenna board has dimensions of 12 × 12 × 0.254 mm3 while the size of the radiating element is 6 × 2 × 0.254 mm3 (0.56λ0 × 0.19λ0 × 0.02λ0). The proposed antenna showed dual band characteristics. The first resonance showed a bandwidth of 10 GHz with a starting frequency of 23 GHz to an ending frequency point of 33 GHz followed by a second resonance bandwidth of 3.25 GHz ranging from 37.75 to 41 GHz, respectively. The proposed antenna is transformed into a four element Linear array system with size of 48 × 12 × 0.254 mm3 (4.48λ0 × 1.12λ0 × 0.02λ0). The isolation levels at both resonance bands were noted to be >20 dB which shows high levels of isolation among radiating elements. The MIMO parameters such as Envelope Correlation Co-efficient (ECC), Mean Effective Gain (MEG) and Diversity Gain (DG) were derived and were found to be in satisfactory limits. The proposed MIMO system model is fabricated and through validation and testing of the prototype, the results were found to be in good agreement with simulations

    mmWave four-element mimo antenna for future 5G systems

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    This paper presents an S-shape four-port Multiple Input Multiple Output (MIMO) wide-band mmWave antenna with bandwidth of 25 GHz to 39 GHz. The antenna is designed on 0.254 mm ultra-thin RO5880 with permittivity of 2.3. The dimensions of proposed S-shape antenna are 10 × 12 mm for single element and 24 × 24 mm for four-port MIMO configuration. A decoupling network is introduced to further compress mutual coupling among MIMO elements. The peak gain achieved is 7.1 dBi and MIMO assembly delivers diversity scheme. The proposed MIMO antenna is fabricated, and simulated results are found to be in excellent agreement with simulations. Through the results obtained, the proposed MIMO antenna system can be considered as a potential candidate for future mmWave devices

    Integrating humanities in healthcare: a mixed-methods study for development and testing of a humanities curriculum for front-line health workers in Karachi, Pakistan

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    Lady health workers (LHWs) provide lifesaving maternal and child health services to >60% of Pakistan’s population but are poorly compensated and overburdened. Moreover, LHWs’ training does not incorporate efforts to nurture attributes necessary for equitable and holistic healthcare delivery. We developed an interdisciplinary humanities curriculum, deriving its strengths from local art and literature, to enhance character virtues such as empathy and connection, interpersonal communication skills, compassion and purpose among LHWs. We tested the curriculum’s feasibility and impact to enhance character strengths among LHWs. We conducted a multiphase mixed-methods pilot study in two towns of Karachi, Pakistan. We delivered the humanities curriculum to 48 LHWs via 12 weekly sessions, from 15 June to 2 September 2021. We developed a multiconstruct character strength survey that was administered preintervention and postintervention to assess the impact of the training. In-depth interviews were conducted with a subset of randomly selected participating LHWs. Of 48 participants, 47 (98%) completed the training, and 34 (71%) attended all 12 sessions. Scores for all outcomes increased between baseline and endline, with highest increase (10.0 points, 95% CI 2.91 to 17.02; p=0.006) observed for empathy/connection. LHWs provided positive feedback on the training and its impact in terms of improving their confidence, empathy/connection and ability to communicate with clients. Participants also rated the sessions highly in terms of the content’s usefulness (mean: 9.7/10; SD: 0.16), the success of the sessions (mean: 9.7/10; SD: 0.17) and overall satisfaction (mean: 8.2/10; SD: 3.3). A humanities-based training for front-line health workers is a feasible intervention with demonstrated impact of nurturing key character strengths, notably empathy/connection and interpersonal communication. Evidence from this study highlights the value of a humanities-based training, grounded in local literature and cultural values, that can ultimately translate to improved well-being of LHWs thus contributing to better health outcomes among the populations they serve

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

    Four port tri-circular ring MIMO antenna with wide-band characteristics for future 5G and mmWave applications

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    MIMO (Multiple-Input-Multiple-Output) antenna systems are promising for fifth-generation (5G) networks, offering lower latency and higher data rates. These systems utilize millimeter-wave (mmWave) frequency bands for efficient transmission and reception of multiple data simultaneously, enhancing overall efficiency and performance. This article presents a compact size, wide band tri-circular ring mmWave MIMO antenna with suitable performance characteristics for next-generation communication systems. The MIMO system consists of a tri-circular ring patch with slots on a ground plane. The four elements of the antenna are arranged together in the polarization diversity configuration with overall dimensions of 23×18×0.254 mm3, and designed on a 0.254 mm thin, flexible RO5880 substrate with a relative permittivity of 2.3 using Computer Simulation Technology (CST) 2022. The proposed antenna design shows the impedance bandwidth of 14 GHz with isolation >18 dB throughout the 26-40 GHz resonance band. The obtained gain is 6.6 dBi at 28 GHz with radiation efficiency > 90%. Several MIMO parameters are also investigated, such as Envelope Correlation Coefficient (ECC), Mean Effective Gain (MEG), Diversity Gain (DG), Total Active Reflection Co-efficient (TARC), and Channel Capacity Loss (CCL), and are found to be within the accepted limits for a practical MIMO system. Furthermore, the fabricated MIMO antenna was tested, and the measured results aligned favorably with the simulated results, confirming the suitability of the proposed design. Through the obtained results, the mmWave MIMO antenna is suitable for practical 5G as well as mmWave applications due to its lightweight, simple design, and wideband characteristics, which cover the 5G frequency bands of 26, 28, 32, and 38 GHz

    Enrichment and distribution of trace elements in Padhrar, Thar and Kotli coals from Pakistan: Comparison to coals from China with an emphasis on the elements distribution

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    This paper reports the mineralogical and geochemical compositions of the Padhrar (salt-range), Thar (Block Nos. 3 and 5) and Kotli coals. The coal investigated in this study is lignite to sub-bituminous coal, with a broad range of ash yields, volatile matter content and sulfur contents. The mineralogical characteristic, major and trace elements were determined by X-ray diffraction, inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry, respectively. The mineral assemblages, sulfur contents, ash yields, and (CaO + MgO + Fe2O3)/(SiO2+ Al2O3) ratio varied significantly in the coal, which is attributed mainly to variation in the depositional environment. Pyritic sulfur is the main form of sulfur in the coals from Padhrar, Kotli and Thar coalfield. The minerals in the studied coals are dominated by quartz, pyrite, kaolinite, illite, along with calcite, feldspar, siderite, montmorillonite and gypsum. Sixteen trace elements, including Li, Be, B, Ti, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, and Ba and five major elements P, Ca, Al, Fe, and Si, were investigated in this study. The trace element concentrations show variety within the coal seams in the Thar coals and the affinities vary among locations. The concentration of Sr, Ti, Zn, Li, Ni, Cu, Sc, As, Be, and B in the present study are within the range of average Chinese coal values, with the exception of V, Cr, Fe, P, and Rb. On the other hand, compared with world coals, the studied coals have higher contents of B, Cr, Li, Fe, V, Rb, P, and Sc. Based on statistical analyses, most of the trace elements, show an affinity to ash yield and possible association with pyrite, kaolinite, and calcite

    An Ultra-Wide Band MIMO Antenna System with Enhanced Isolation for Microwave Imaging Applications

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    This paper introduces a novel two-port ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna system with enhanced isolation characteristics. The antenna, designed on a thin 0.787 mm RO5880 substrate, achieves a compact form factor of 52 × 26 mm2 and offers a wide bandwidth of 9.2 GHz (2.3 GHz to 11.5 GHz) while meeting the VSWR 2:1 criterion. Notably, the proposed antenna demonstrates an impressive increase in isolation, up to 16 dB, through the integration of a shared radiator with small rectangular slots, effectively reducing interference and improving overall performance. Furthermore, a comprehensive analysis of additional MIMO performance parameters, including the envelope correlation coefficient (ECC) and diversity gain, confirms their satisfactory limits, validating the potential of the proposed UWB-MIMO antenna for various UWB applications. The time domain analysis of the UWB antenna is also analyzed, and results are found to be within satisfactory limits. Simulation and measurement results further support the practicality and effectiveness of the antenna design, highlighting its compact size, wide bandwidth, and enhanced isolation characteristics, positioning it as a promising solution for advanced UWB microwave imaging systems

    A systematic review on global pollution status of particulate matter-associated potential toxic elements and health perspectives in urban environment

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    Airborne particulate matter (PM) that is a heterogeneous mixture of particles with a variety of chemical components and physical features acts as a potential risk to human health. The ability to pose health risk depends upon the size, concentration and chemical composition of the suspended particles. Potential toxic elements (PTEs) associated with PM have multiple sources of origin, and each source has the ability to generate multiple particulate PTEs. In urban areas, automobile, industrial emissions, construction and demolition activities are the major anthropogenic sources of pollution. Fine particles associated with PTEs have the ability to penetrate deep into respiratory system resulting in an increasing range of adverse health effects, at ever-lower concentrations. In-depth investigation of PTEs content and mode of occurrence in PM is important from both environmental and pathological point of view. Considering this air pollution risk, several studies had addressed the issues related to these pollutants in road and street dust, indicating high pollution level than the air quality guidelines. Observed from the literature, particulate PTEs pollution can lead to respiratory symptoms, cardiovascular problems, lungs cancer, reduced lungs function, asthma and severe case mortality. Due to the important role of PM and associated PTEs, detailed knowledge of their impacts on human health is of key importance

    Synergistic effects of biochar and processed fly ash on bioavailability, transformation and accumulation of heavy metals by maize (Zea mays L.) in coal-mining contaminated soil

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    In the paper, hydrothermally (HT) treated, sulfuric acid (H2SO4), and hydrochloric acid (HCI) washed fly ashes (FA) were used to examine the applied effects with and without biochar (BC) on the bioavailability of heavy metals (HMs) and growth of maize (Zea mays L) plants in coal -mining contaminated soil. Addition of BC in combination with these processed fly ashes (PFA) significantly increased the soil pH, EC, and soil organic carbon (SOC). Individual application of BC and PFA increased the available contents of Mg, Mn, and Fe, while the combination of BC and PFA significantly decreased the bioavailability of HMs in soil compared to control. The BC + HT-FA and BC + H2SO4-FA were most efficient treatments followed by BC + HCl-FA in promoting plant growth parameters (i.e., fresh and dry biomass, root and shoot lengths), reduction in the uptake of HMs and increase in the uptake of macronutrients. The results established that the combined application of BC and PFA synergistically increased HMs immobilization and maize biomass yields. The lowest transfer rate (TR), bioconcentration factor (BCF), and translocation factor (TF) for Cr, Co, Ni, Cu, Zn, Cd, and Pb were detected in BC + HT-FA, followed by BC + H2SO4-FA and BC + HCl-FA treatments after 60 days of maize crop harvesting. It could be suggested that using BC along with PFA as a soil stabilizer may be a promising source to immobilize HMs in a coal -mining contaminated soil. (C) 2019 Elsevier Ltd. All rights reserved
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