Safety analysis of intermittent hemodialysis in patients with continuous flow left ventricular assist devices

Dialysis centers adopt a cautious approach when it comes to performing intermittent hemodialysis (HD) on patients with continuous flow (CF) left ventricular assist devices (LVADs) because of the potential for volume flux‐related complications and absence of pulsatile blood pressure for monitoring. Many patients have to remain hospitalized because of the inability of the dialysis centers to accept them for outpatient dialysis. In this study, the effect of HD was observed in such patients. Between June 2009 and October 2012, 139 patients received LVADs, of which 10 patients (7%) required intermittent HD postoperatively. The mean age of the patients was 53 ± 14 years and 90% were men. A total of 281 dialysis sessions were administered amounting to 1025 hours of dialysis. The mean systolic blood pressure monitored with Doppler device was 97 ± 18 mmHg. Dialysis durations averaged 218 ± 18 minutes. Mean blood flow rate was 334 ± 38 cc/min, and 2.6 ± 1.1 L was ultrafiltrated during each session. Only 15 (5.3%) sessions were interrupted or terminated in six patients. The reasons for termination were symptomatic hypotension—6 (2.1%), asymptomatic hypotension—3 (1%), ventricular tachycardia—1 (0.36%), dialysis machine malfunction—2 (0.7%), low phosphorus—2 (0.7%), and abdominal cramps—1 (0.36%). Volume expansion was necessary on three occasions. Low‐flow device alarms were registered during two (0.71%) sessions. The results showed no serious adverse effects or deaths.     

Control of Grid Connected Photovoltaic Systems with Microinverters: New Theoretical Design and Numerical Evaluation

This paper addresses the problem of controlling grid connected photovoltaic (PV) systems that are driven with microinverters. The systems to be controlled consist of a solar panel, a boost dc–dc converter, a DC link capacitor, a single‐phase full‐bridge inverter, a filter inductor, and an isolation transformer. We seek controllers that are able to simultaneously achieve four control objectives, namely: (i) asymptotic stability of the closed loop control system; (ii) maximum power point tracking (MPPT) of the PV module; (iii) tight regulation of the DC bus voltage; and (iv) unity power factor (PF) in the grid. To achieve these objectives, a new multiloop nonlinear controller is designed using the backstepping design technique. A key feature of the control design is that it relies on an averaged nonlinear system model accounting, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of the PV panel. To achieve the MPPT objective, a power optimizer is designed that computes online the optimal PV panel voltage used as a reference signal by the PV voltage regulator. It is formally shown that the proposed controller meets all the objectives. This theoretical result is confirmed by numerical simulation tests.     

A Sensorless State Estimation for A Safety-Oriented Cyber-Physical System in Urban Driving: Deep Learning Approach

In today's modern electric vehicles,enhancing the safety-critical cyber-physical system(CPS)'s performance is necessary for the safe maneuverability of the vehicle.As a typical CPS,the braking system is crucial for the vehicle design and safe control.However,precise state estimation of the brake pressure is desired to perform safe driving with a high degree of autonomy.In this paper,a sensorless state estimation technique of the vehicle's brake pressure is developed using a deep-learning approach.A deep neural network(DNN)is structured and trained using deep-learning training techniques,such as,dropout and rectified units.These techniques are utilized to obtain more accurate model for brake pressure state estimation applications.The proposed model is trained using real experimental training data which were collected via conducting real vehicle testing.The vehicle was attached to a chassis dynamometer while the brake pressure data were collected under random driving cycles.Based on these experimental data,the DNN is trained and the performance of the proposed state estimation approach is validated accordingly.The results demonstrate high-accuracy brake pressure state estimation with RMSE of 0.048 MPa.     

Effects of hot water pre-extraction on surface properties of bagasse soda pulp

In this work, the effects of hot water pre-extraction of depithed bagasse on the soda pulping and surface properties were studied. The conditions of hot water pre-extraction were: maximum temperature 170 °C, heat-up time 90 min, time at maximum temperature 10 min, and solid to liquor ratio (S:L) 1:8. Consequently, the pre-extracted and un-extracted bagasse chips were subjected to soda pulping at 160 °C for 1 h with 11, 14 and 17% active alkali charge and an S:L of 1:5. The results showed that the hot water pre-extraction increased bagasse surface texture porosity by hemicellulose degradation. Therefore, the delignification was faster for pulping of pre-extracted samples. At a certain charge of alkali, pre-extracted samples showed higher screened yield and lower Kappa number. For instance, at 17% alkali charge, pre-extracted bagasse gave 11.3% higher pulp yield compared with the un-extracted ones. Inverse gas chromatography (IGC) results showed that the hot water pre-extraction changed the active sites on the bagasse surface, decreasing the dispersive energy and the basicity character, and affected the particle morphology. The pulping process decreased the hydrophobicity and the basicity of the bagasse surface. The surfaces of un-extracted and pre-extracted bagasse pulps had similar properties but different morphology. The pulps present higher surface area and permeability with more reactive capacity.     

Removal of Acid Orange 7 and Remazol Black 5 reactive dyes from aqueous solutions using a novel biosorbent

This study utilizes canola stalks (CS), an agro-residue, as a biosorbent to remove two different dyes, namely Acid Orange 7 (AO7) and Remozol Black 5 (RB5) from aqueous solutions. The effects of operational parameters on the efficiency of dye removal including pH, adsorbent mass, initial dye concentration and contact time have been investigated. For both tested dyes, the maximum absorption capacity was reached at initial pH 2.5 and 120 min contact time. The results showed that the absorption of both dyes depended on the pH of milieu, temperature, dye and CS concentrations. Freundlich and Langmuir models were used to analyze the obtained experimental data. The isotherms are found to be linear over the entire concentration range for both dyes. The highest value of linear correlation coefficients for AO7 (0.9926) and RB5 (0.9882) showed that the Langmuir is the best model to fit the experimental data. Kinetic study of absorption was done applying the pseudo first-order and the pseudo second-order equations. Absorption of both dyes could be well predicted by the pseudo second-order equation. The obtained results are very promising since: (i) high levels of dye removal (> 90%) were achieved with low contact times biosorbent/dye (less than 20 min contact); and (ii) the whole CS can be successfully used as biosorbent of AO7 and RB5 dyes in aqueous solution without needing any chemical modifications.     

Optical properties of poly(vinyl chloride)/poly(ethylene oxide) blend

The relatively high dielectric constant poly(vinyl chloride) (PVC) was blended with poly(ethylene oxide) (PEO) polymer electrolytes to improve their electrical conductivity from the optical spectra of the given polymeric system. The optical properties in the UV–visible region of PVC polymer containing 0%, 20%, 50% and 70% by weight PEO are reported. The optical results obtained were analyzed in terms of the absorption formula for non-crystalline materials. The absorption coefficient and the optical band energy gap (E_opt) have been obtained from direct allowed transitions in k-space at room temperature. The width of the tail of localized states in the band gap (ΔE) was evaluated using the Urbach-edges method. It was found that both (E_opt) and (ΔE) vary with the concentration of the PEO complex in the polymer matrix. In addition, a correlation between the energy gap and the ac-conductivity as a function of PEO complex concentration is also reported.     

Analysis of MWCNT/epoxy composites at microwave frequency: reproducibility investigation

A wide-band microwave characterization of nanocomposites based on commercial multiwalled carbon nanotubes (MWCNTs) and epoxy resin is presented. The sample preparation method is discussed in detail. Field emission scanning electron microscopy is used for morphological sample analysis of nanocomposites and MWCNTs. The complex permittivity is measured in a wide frequency band (3 to 18 GHz) using a commercial dielectric probe (Agilent 85070D) and a network analyzer (E8361A). A statistical analysis based on one-way analysis of variance (ANOVA) technique is performed. The aim of this statistical analysis is to investigate the influence of concentration of nanoparticles inside the polymer matrix on the complex permittivity. This can be significantly different in nanocomposites even if the samples have similar electrical properties.     

A comparative study on the effects of Coriolus versicolor on properties of HDPE/wood flour/paper sludge composites

In this study, the effects of white-rot fungus (Coriolus versicolor) on the properties of high density polyethylene (HDPE)/wood flour/paper sludge composites were examined. In addition, the effectiveness of using coupling agent on the durability of decayed and undecayed WPCs was investigated. Two different types of sludge materials, namely paper making waste water sludge (PS) and ink-eliminated sludge (IES) were used. The mechanical properties, morphology, and water absorption of fabricated composites were investigated. At a similar wood flour loading, except for modulus of elasticity, the fungi treated composites showed lower mechanical properties (such as modulus of rupture and unnotched Izod impact strength), and higher water absorption compared to untreated composites. According to the results, addition of wood flour decreased the resistance of the composites to moisture and fungal environment. The exposure of the composites to a 4-cycle (2, 24, 48 and 72 h) water immersion caused serious damage to the interfacial adhesion between wood flour and polymer matrix due to contraction and swelling stresses developed during the cyclic exposure. The detrimental effect of fungal treatment on the water uptake of the composites could be explained by the degradation of lignin which made the cellulose content more accessible. Further, it makes chains of cavities that accelerate water absorption. However, the weight losses of all cases of treated composites were low (less than 2.5%), while PS filled composites were more susceptible to white-rot fungi. The addition of coupling agent during the compounding of wood flour and HDPE prevented the colonization and proliferation of fungus on the surface of the composites, and had an advantageous effect on the water uptake and mechanical properties of both treated and untreated composites.     

Analysing Various Control Technics for Manipulator Robotic System (Robogymnast)

The Robogymnast is a highly complex, three-link system basedon the triple-inverted pendulum and is modelled on the human example ofa gymnast suspended by their hands from the high bar and executing largerand larger upswings to eventually rotate fully. The links of the Robogymnastcorrespond respectively to the arms, trunk, and lower limbs of the gymnast,and from its three joints, one is under passive operation, while the remainingtwo are powered. The passive top joint poses severe challenges in attainingthe smooth movement control needed to operate the Robogymnast effectively.This study assesses four types of controllers used for systems operation andidentifies how far response stabilisation is achieved with each. The system issimulated using MATLAB Simulink, with findings generated regarding risingand settling time, as well as overshoot. The research primarily seeks to examine the application of a linear quadratic regulator controller, proportionalintegral-derivative controller, fuzzy linear quadratic regulator controller andlinear quadratic regulator- proportional-integral-derivative controller for thistype of system and comparisons between the different controllers to demonstrate successful performance, which highlights the claimed advantages of theproposed system.