Novel algebraic meal disturbance estimation based adaptive robust control design for blood glucose regulation in type 1 diabetes patients

This study designs a robust closed‐loop control algorithm for elevated blood glucose level stabilisation in type 1 diabetic patients. The control algorithm is based on a novel control action resulting from integrating algebraic meal disturbance estimator with back‐stepping integral sliding mode control (BISMC) technique. The estimator shows finite time convergence leading to accurate and fast estimation of meal disturbance. Moreover, compensation of the estimated disturbance in controller provides significant reduction in chattering phenomenon, which is inherent drawback of sliding mode control (SMC). The controller is applied to one of the most reliable models of type 1 diabetic patients, named Bergman''s minimal model. The effectiveness and superiority of the designed controller is shown by comparing it to classical SMC and super‐twisting sliding mode control. The designed controller is subject to three different cases for detailed analysis of the controller''s robustness against meal disturbance. The three cases considered are hyperglycaemia, hyperglycaemia combined with meal disturbance and three meal disturbance. The simulation results confirm superior performance of algebraic disturbance estimator based BISMC controller for all the cases mentioned above.Inspec keywords: closed loop systems, robust control, sugar, medical control systems, variable structure systems, control system synthesis, blood, nonlinear control systems, adaptive control, diseasesOther keywords: adaptive robust control design, blood glucose regulation, type 1 diabetes patients, closed‐loop control algorithm, elevated blood glucose level stabilisation, type 1 diabetic patients, novel control action, algebraic meal disturbance estimator, mode control technique, accurate estimation, estimated disturbance, super‐twisting sliding mode control, algebraic disturbance estimator, BISMC controller, algebraic meal disturbance estimation, back‐stepping integral sliding mode control technique     

A Novel Compact Highly Isolated UWB MIMO Antenna with WLAN Notch

This paper presents a compact Multiple Input Multiple Output (MIMO) antenna with WLAN band notch for Ultra-Wideband (UWB) applications. The antenna is designed on 0.8 mm thick low-cost FR-4 substrate having a compact size of 22 mm × 30 mm. The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer. The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure. The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports. A slot is etched in the radiating patch for WLAN band notch. The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz. The results show that the proposed antenna has a very good impedance bandwidth of |S11| < −10 dB within the frequency band from 3.1–14 GHz. A low mutual coupling of less than −23 dB is achieved within the entire UWB band. Furthermore, the antenna has a peak gain of 5.8 dB, low ECC < 0.002 and high Diversity Gain (DG > 9.98).     

Experimental and analytical study of carbon fiber-reinforced polymer (FRP)/autoclaved aerated concrete (AAC) sandwich panels

The structural behavior of hybrid fiber-reinforced polymer (FRP)–autoclaved aerated concrete (AAC) panels has been investigated. FRP laminates can be used to reinforce externally the plain AAC producing a very high stiff panel. The resulting hybrid FRP/AAC panel can be used as structural or non-structural member for the housing construction. In order to accomplish this, FRP/AAC panels have been fabricated and prepared for testing. The specimens have been processed using the advanced semi-mechanical processing technique VARTM (Vacuum Assisted Resin Transfer Molding). The concept of the FRP/AAC panel is based on the theory of sandwich construction with strong and stiff skins, like FRP composites, bonded to a core material, like AAC panel. The FRP composite material was made of carbon reinforcing fabrics embedded in an epoxy resin matrix. The panels were tested under four-point bending test to investigate their strength and ductility responses using a Tinius–Olsen Universal Testing Machine. Experimental results showed a significant influence of FRP laminates on both strength and ductility of the FRP/AAC panels. A theoretical analysis was conducted to predict the strength of the FRP/AAC member and results found were in good accordance with the experimental ones.     

High‐Performance Polymers Sandwiched with Chemical Vapor Deposited Hexagonal Boron Nitrides as Scalable High‐Temperature Dielectric Materials

Polymer dielectrics are the preferred materials of choice for power electronics and pulsed power applications. However, their relatively low operating temperatures significantly limit their uses in harsh‐environment energy storage devices, e.g., automobile and aerospace power systems. Herein, hexagonal boron nitride (h ‐BN) films are prepared from chemical vapor deposition (CVD) and readily transferred onto polyetherimide (PEI) films. Greatly improved performance in terms of discharged energy density and charge–discharge efficiency is achieved in the PEI sandwiched with CVD‐grown h ‐BN films at elevated temperatures when compared to neat PEI films and other high‐temperature polymer and nanocomposite dielectrics. Notably, the h ‐BN‐coated PEI films are capable of operating with >90% charge–discharge efficiencies and delivering high energy densities, i.e., 1.2 J cm^?3, even at a temperature close to the glass transition temperature of polymer (i.e., 217 °C) where pristine PEI almost fails. Outstanding cyclability and dielectric stability over a straight 55 000 charge–discharge cycles are demonstrated in the h ‐BN‐coated PEI at high temperatures. The work demonstrates a general and scalable pathway to enable the high‐temperature capacitive energy applications of a wide range of engineering polymers and also offers an efficient method for the synthesis and transfer of 2D nanomaterials at the scale demanded for applications.     

Melt extrusion of polyethylene nanocomposites reinforced with nanofibrillated cellulose from cotton and wood sources

Replacing petroleum‐based materials with biodegradable materials that offer low environmental impact and safety risk is of increasing importance in sustainable materials processing. The objective of this study was to produce uniform nanofibrillated cotton from recycled waste cotton T‐shirts using microgrinding techniques and compare its performance as reinforcing agent in thermoplastic polymers constructs with wood‐originated materials. The effect of the microgrinding process on morphology, crystallinity, and thermal stability of materials was evaluated by transmission electron microscopy (TEM), scanning electron microscope (SEM), X‐ray diffraction (XRD), and thermogravimetry analysis (TGA). Nanofibrillated cotton resulted in higher crystallinity and thermal stability than fibrillated bleached and unbleached softwood. All the materials were extruded with low‐density polyethylene to fabricate nanocomposite films. Nanofibrillated cotton nanocomposites had a higher optical transparency than did the wood‐based composites. The mechanical properties of the nanofibrillated cotton nanocomposites were largely improved and showed 62.5% increase in strength over the wood‐based nanofibrillated containing composites, in agreement with the higher crystallinity of the nanosized cotton‐derived filler material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41857.     

Modification of Magnetite Cellulose Nanoparticles via Click Reaction for use in Controlled Drug Delivery

Superparamagnetic Fe₃O₄ nanoparticles (MNPs) were functionalized by modified cellulose. The modified cellulose was synthesized through bromoacetylation of cellulose (BACell) followed by the substitution of sodium azide to form BACell-N₃. The remaining methylene bromide groups on BACell-N₃ was further reacted with the MNPs to form Fe₃O₄/Cell-N₃. Then propargyl alcohol (PA) was immobilized on the azide-terminated Fe₃O₄ nanoparticles through copper (I)-catalyzed azide-alkyne cycloaddition (click reaction) to form Fe₃O₄/Cell/TAA nanoparticles. Doxorubicin (DOX) was loaded on prepared nanoparticles and release profiles of the DOX as a model drug from the Fe₃O₄/Cell/TAA nanoparticles and its loading capacity were determined by UV–Vis absorption at λ_max 483?nm.     

Oxygen‐releasing biomaterials for tissue engineering

Due to the increasing demand to generate thick and vascularized tissue‐engineered constructs, novel strategies are currently being developed. An emerging example is the generation of oxygen‐releasing biomaterials to tackle mass transport and diffusion limitations within engineered tissue constructs. Biomaterials containing oxygen‐releasing molecules can be fabricated in various forms, such as hybrid thin films, microparticles or three dimensional scaffolds. In this perspective, we summarize various oxygen‐releasing reagents and their potential applications in regenerative engineering. Moreover, we review the main approaches for fabricating oxygen‐releasing biomaterials for a range of tissue engineering applications. © 2013 Society of Chemical Industry     

Physical,mechanical, and transdermal diltiazem release analysis of nanosilica tailored various poly(vinyl alcohol) membranes

Hybrid membranes based on poly(vinyl alcohol) (PVA) of widely different molecular weights and ex situ nanosilica were synthesized and characterized as transdermal delivery device for Diltiazem hydrochloride. Investigations showed that change in PVA molecular weight strongly influenced physico‐mechanicals of the hybrids especially at low nanosilica content than at higher levels. As for example at 1 wt %, low molecular weight PVA induced finer dispersion of silica nanoparticles resulting into higher dry state crystallinity and mechanical strength but slightly lower biocompatibility as compared to high molecular weight PVA. Those variations in physico‐mechanicals finally affected Diltiazem retention and its elution from those membranes under physiological conditions. Low molecular weight PVA produced highest drug retention as well as slowest yet steady release than both high molecular weight PVA and neat PVA membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2076–2086, 2013