Surfactant-aided impregnation of MnF2 into CNT fabrics as cathode material with high electrochemical performance for lithium ion batteries

© 2018 Elsevier Ltd MnF2 infiltrated-CNT fabrics was prepared by surfactant-aided impregnation of MnSiF6 precursors in acid-treated CNT fabric followed by annealing MnSiF6-loaded CNT fabric. The structural and morphological characterizations by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the formation of MnF2 nanoparticles (average size: 20–30 nm) within CNT fabric structure. Galvanostatic charge-discharge tests of CNT-MnF2 nanocomposite fabrics showed excellent electrochemical performance and good cycle stability between 0.4 and 4.0 V vs Li/Li+. A specific capacity of 388 mAh/g was measured at 0.1C for CNT-MnF2 fabric with 70% MnF2 loading after 100 cycles. Stable cyclability and good rate performance were obtained at high charge-discharge cycling rates. MnF2 loading largely affect the performance of MnF2 infiltrated-CNT fabrics cathodes when lower than 70% MnF2 loaded-CNT fabrics were prepared. It can be concluded that nano-sized active materials infiltrated inside conductive carbon matrix in optimized content can lead to rapid kinetics and stable performance for flexible metal fluoride-based cathode materials.This work was funded by a grant from the Qatar National Research Fund under its National Priorities Research Program award number NPRP7-567-2-216 . Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Qatar National Research Fund . The authors are thankful to Prof Gleb Yushin from Georgia Institute of Technology for his collaboration in this subject

Bin stored wheat temperature simulation under South Mediterranean climate

Cereal quality preservation is traditionally the accountability of grain storekeepers who count on profound knowledge discovered through scientific research. The main purpose of this research study was to predict the evolution of wheat temperature in unaerated silo during storage period under Tunisia climate. First, a bidimensional mathematical combined model (silo wall model + heat transfer model in grain bulk), which describes the distribution of the unsteady temperature in a cylindrical grain storage system, was presented and simulated using the parabolic solver incorporated in the Matlab 2015a environment. Mesh refinement at the shortest boundaries, including triangular elements, was adopted to simulate storage temperatures. In this numerical model, the influence of Newman boundary conditions, which include solar irradiation and air convection, on the evolution and distribution of grain temperatures was considered. Second, the model was validated by conducting experiments in a weathered galvanized steel silo with conical bottom, preserving wheat during the period of autumn 2019. Utilizing the climatic data of the region of Medjez El Bab, located in Western North of Tunisia, the variations in stored grain temperatures were interpreted in detail. The obtained results when comparing the observed versus numerical data proved an excellent agreement according to the correlation coefficients  for different measurement points (from 0.85 to 0.98), confirming that the developed model is an outstanding tool to monitoring and to predicting wheat conservation for regions with similar climate conditions as Tunisia

Diagnosis of papilledema and pseudopapilledema using optical coherence tomography

Background: Papilledema is a common clinical problem where the ophthalmologist plays an important role in its diagnosis. Optical coherence tomography (OCT) provides high resolution images of the retina and the retinal nerve fiber layer (RNFL).Objective: The aim of the work was early and non- invasive diagnosis of papilledema and differentiating it from pseudopapilledema using optical coherence tomography (OCT).Patients and methods: This observational case control study included a total of 45 eyes stratified into 3 equally groups, 15 each, (Group-1): eyes of healthy normal subjects, (Group-2) eyes with papilledema and (Group-3) eyes with pseudo-papilledema. Patients presented at Ophthalmology Outpatient Clinic, Zagazig University Hospitals. Follow-up visits included an interview with the patient for assessing the presence of ocular symptoms, and for ophthalmologic examination to register all the clinical findings.Results: There is statistically significant difference between the studied groups regarding result of fundus examination. Normal control group had normal appearance of fundus. Concerning pseudo papilledema, 73.3% had crowded disc and 26.7% had dusen. Concerning papilledema, 40% had mild lesion, 20% had moderate and remaining 40% had severe lesion. There is statistically significant difference between the studied groups regarding morphological changes. Crowded disc and buried optic disc drusen occurred in 73.3% and 26.7% of pseudopapilledema group respectively). There is statistically significant difference between the studied groups regarding superior RNFL. On LSD comparison, the difference is significant between each individual groups. There is statistically significant difference between the studied groups regarding inferior RNFL.Conclusion: It could be concluded that spectral domain optical coherence tomography can differentiate between papilledema, pseudopapilledema, and a normal disc

A Disposable Microfluidic Device with a Screen Printed Electrode for Mimicking Phase II Metabolism

Human metabolism is investigated using several in vitro methods. However, the current methodologies are often expensive, tedious and complicated. Over the last decade, the combination of electrochemistry (EC) with mass spectrometry (MS) has a simpler and a cheaper alternative to mimic the human metabolism. This paper describes the development of a disposable microfluidic device with a screen-printed electrode (SPE) for monitoring phase II GSH reactions. The proposed chip has the potential to be used as a primary screening tool, thus complementing the current in vitro methods

Charge and Hydrophobicity Effects of NIR Fluorophores on Bone-Specific Imaging

Recent advances in near-infrared (NIR) fluorescence imaging enabled real-time intraoperative detection of bone metastases, bone growth, and tissue microcalcification. Pamidronate (PAM) has been widely used for this purpose because of its high binding affinity toward bone and remarkable therapeutic effects. Herein we describe the development of a series of PAM-conjugated NIR fluorophores that varied in net charges and hydrophobicity, and compared their bone targeting efficiency, biodistribution, and blood clearance. Since the targeting moiety, PAM, is highly negatively charged but small, the overall in vivo bone targeting and biodistribution were mediated by the physicochemical properties of conjugated fluorophores

Design technique to mitigate unwanted coupling in densely packed radiating elements of an antenna array for electronic devices and wireless communication systems operating in the millimeter-wave band

An innovative design is presented of a metamaterial inspired antenna array for millimeter-wave band applications where non-mechanical beam-steering is required such as in 5G and 6G communications, automotive and radar systems. In communication systems beam-steering antennas can significantly improve signal-to-noise ratio, spatial directivity, and the efficiency of data transmission. However, in tightly packed arrays the effects of mutual coupling between the radiating elements can severely limit the array’s performance. The proposed antenna array consists of a 3×3 matrix of patch radiators that are tightly packed and interconnected to each other. Rows of radiators are demarcated by a horizontal microstrip transmission-line whose ends are short-circuited to the ground-plane. This technique reduces unwanted surface waves that contribute to undesired coupling. Embedded in the square patch radiators is a rhombus shaped slot that increases the effective aperture of the antenna with no impact on the antenna’s size. As the antenna is excited via a single feedline the edge-to-edge spacing between the radiators and the interconnected feedlines are made such that there is phase coherency at the radiating elements. Measured results show that the effectiveness of the proposed array in simultaneously improving its impedance bandwidth and radiation characteristics. The measured peak gain and radiation efficiency are 13.6 dBi and 89.54%, respectively