Eco-friendly Concrete Using Local Materials From Sudan

This study is aimed at investigating the potentiality for utilizing some locally available eco-friendly materials to replace some concrete constituents as a possible opportunity to introduce sustainable construction in Sudan. Six suggested scenarios were explored to visualize the possible outcomes : (1) 100% recycled aggregates (RA) and natural pozzolana in replacement of coarse aggregates (2) steel slag replacing fine aggregate or cement (3) treated sawdust replacing fine aggregates (4) sawdust ash in partial replacement of cement (5) meta-kaolin (MK) in partial substitution for ordinary Portland cement (OPC) (6) quarry dust (QD) in partial replacement of sand or cement. Laboratory experiments were conducted and concrete workability and compressive strength were determined. The results confirmed the suitability of RA for full replacement of natural coarse aggregates. Steel slag was more appropriate in replacing sand than cement when added in small percentages not exceeding 15%. Sawdust needed treatment to eliminate the unfavorable properties before using it as a substitute for sand but when the ash was used to replace cement, it was not possible to achieve the required strength at early ages and better results were achieved in 28 days. With a chemical composition comparable to cement, MK showed impressive results when used in partial replacement of OPC. The addition of QD in replacement of 15% of sand offered a reasonable workability but the compressive strength was only approaching the targeted value. According to these results, it could be inferred that the tested options offer reasonable evidence to confirm their potentiality for producing green concrete in Sudan

Imperceptible electrooculography graphene sensor system for human-robot interface

Electrooculography (EOG) is a method to record the electrical potential between the cornea and the retina of human eyes. Despite many applications of EOG in both research and medical diagnosis for many decades, state-of-the-art EOG sensors are still bulky, stiff, and uncomfortable to wear. Since EOG has to be measured around the eye, a prominent area for appearance with delicate skin, mechanically and optically imperceptible EOG sensors are highly desirable. Here, we report an imperceptible EOG sensor system based on noninvasive graphene electronic tattoos (GET), which are ultrathin, ultrasoft, transparent, and breathable. The GET EOG sensors can be easily laminated around the eyes without using any adhesives and they impose no constraint on blinking or facial expressions. High-precision EOG with an angular resolution of 4 degrees of eye movement can be recorded by the GET EOG and eye movement can be accurately interpreted. Imperceptible GET EOG sensors have been successfully applied for human-robot interface (HRI). To demonstrate the functionality of GET EOG sensors for HRI, we connected GET EOG sensors to a wireless transmitter attached to the collar such that we can use eyeball movements to wirelessly control a quadcopter in real time

Energy-Efficient Control Adaptation with Safety Guarantees for Learning-Enabled Cyber-Physical Systems

Neural networks have been increasingly applied for control in learning-enabled cyber-physical systems (LE-CPSs) and demonstrated great promises in improving system performance and efficiency, as well as reducing the need for complex physical models. However, the lack of safety guarantees for such neural network based controllers has significantly impeded their adoption in safety-critical CPSs. In this work, we propose a controller adaptation approach that automatically switches among multiple controllers, including neural network controllers, to guarantee system safety and improve energy efficiency. Our approach includes two key components based on formal methods and machine learning. First, we approximate each controller with a Bernstein-polynomial based hybrid system model under bounded disturbance, and compute a safe invariant set for each controller based on its corresponding hybrid system. Intuitively, the invariant set of a controller defines the state space where the system can always remain safe under its control. The union of the controllers' invariants sets then define a safe adaptation space that is larger than (or equal to) that of each controller. Second, we develop a deep reinforcement learning method to learn a controller switching strategy for reducing the control/actuation energy cost, while with the help of a safety guard rule, ensuring that the system stays within the safe space. Experiments on a linear adaptive cruise control system and a non-linear Van der Pol's oscillator demonstrate the effectiveness of our approach on energy saving and safety enhancement

Idiopathic short-coupled ventricular tachyarrhythmias: Systematic review and validation of electrocardiographic indices

Introduction: Idiopathic short-coupled ventricular tachyarrhythmias make up a considerable proportion of ventricular tachyarrhythmias in structurally normal hearts and are the cause of 5–10% of unexpected sudden cardiac deaths. There is disparity in the literature regarding their description and a lack of formal diagnostic criteria to define them. Objective: To validate ECG indices for the diagnosis of these ventricular tachyarrythmias and to subsequently unify their differing descriptions in the literature under a new terminology: Idiopathic Short-Coupled Ventricular Tachyarrhythmias. Methods: We conducted a systematic review of all published studies describing short-coupled torsades de pointes, idiopathic ventricular fibrillation and polymorphic ventricular tachycardia. Published tracings were analysed using a standard set of criteria to define the different ECG intervals. Previously proposed diagnostic indices were validated using a control group of previously published long-coupled torsades de pointes cases. Results: Validation of the ECG indices revealed that a coupling interval < 400 ms was the most reliable measurement (sensitivity 100%, specificity 97%), followed by a coupling interval/QT < 1 (sensitivity 96%, specificity 100%). Conclusion: Idiopathic short-coupled ventricular tachyarrhythmias encompass all previous descriptions of this tachyarrhythmia including idiopathic ventricular fibrillation, short-coupled torsades de pointes, Purkinje-related torsades de pointes and idiopathic polymorphic ventricular tachycardia. This arrhythmia can be diagnosed by newly proposed criteria with high sensitivity and specificity. Keywords: Ventricular tachyarrhythmia, Purkinje fibres, Reentry, Delayed afterdepolarization, Electrocardiography, Sudden cardiac deat