Parkinson's disease (PD) is a chronic progressive disease caused by loss of dopaminergic neurons in the substantia nigra, degenerating the nervous system of a patient over time. Freezing of gait (FOG), which is a form of akinesia, is a symptom of PD. Meanwhile, recent studies show that the gait of PD patients experiencing FOG can be significantly improved by providing the regular visual or auditory patterns for the patients. In this paper, we propose a gait-aid system built upon smart glasses. Our system continuously monitors the gait and so on of a PD patient to detect FOG, and upon detection of FOG it projects visual patterns on the glasses as if the patterns were actually on the floor. Conducting experiments involving ten PD patients, we demonstrate that our system achieves the accuracy of 92.86 % in detecting FOG episodes and that it improves the gait speed and stride length of PD patients by 15.3  ∼  37.2% and 18.7   ∼  31.7%, respectively.

The present study has been focused on the environment-friendly corrosion inhibitor. Conifer cone (Pinus resinosa) has been used as a novel corrosion inhibitor to mitigate the corrosion of steel rebars in simulated concrete pore solutions (SCPS) in the presence and absence of chloride ions. The corrosion inhibitor is extracted by simple chemical methods. The functional groups present in the extracted conifer cone (ECC) powder are characterized as well as the surface morphology of ECC has been examined. The corrosion inhibition performance has been evaluated by the electrochemical and weight loss methods. The experimental results indicate that ECC possesses a corrosion inhibition efficiency of 81.2% at a dosage of 1000 mg·L–1, after 720 h of immersion in chloride-contaminated SCPS. Adsorption isotherm and their standard Gibbs free energy (ΔG ads 0) values are calculated by Langmuir, Freundlich, and Temkin isotherm methods, and the results indicate that the ECC is initially adsorbed on the steel rebar surface by physisorption and then it turns to chemisorption. The steel rebar surfaces have been characterized after exposure to the ECC containing SCPS, and the results indicate that the ECC containing cationic adsorbate molecules, which interact with steel rebar, leads to retardation of metal dissolution in corrosive chloride medium.

In the present study, different amounts, i.e., 1–3 v/v% of 1 M ammonium phosphate monobasic, were used as an eco-friendly corrosion inhibitor to mitigate the corrosion of steel rebar exposed to simulated concrete pore (SCP) + 3.5 wt% NaCl solution at a prolonged duration. Potentiodynamic polarization results show that as the amount of inhibitor is increased, the corrosion resistance of steel rebar is increased. The steel rebar exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution exhibited nobler corrosion potential (Ecorr), the lowest corrosion current density (icorr), and 97.62% corrosion inhibition efficiency after 1 h of exposure. The steel rebars exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution revealed higher polarization resistance (Rp) and film resistance (R0) with exposure periods compared to other samples owing to the formation of passive film. The scanning electron microscopy (SEM) of steel rebar exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution showed homogenous and uniform dendritic passive film which covers all over the surface, whereas, bare, i.e., SCP + 3.5 wt% NaCl solution exposed samples exhibited pitting and irregular morphology. Raman spectroscopy results confirm the formation of goethite (α-FeOOH), maghemite (γ-Fe2O3), and iron phosphate (FePO4) as a passive film onto the steel rebar surface exposed to 3% inhibitor-containing SCP + 3.5 wt% NaCl solution. These phases are responsible for the corrosion mitigation of steel rebar which are very protective, adherent, and sparingly soluble.

In the present study, different contents, i.e., 1–3% of 0.5 M ammonium phosphate mono basic (APMB), were used as corrosion inhibitor to reduce the corrosion of steel rebar. Electrochemical impedance spectroscopy (EIS) results showed that up to 24 h of exposure, polarization resistance (Rp) and passive/oxide film resistance (Ro) gradually decreased in simulated concrete pore (SCP) + 3.5 wt.% NaCl solution owing to the reduction in pH of the solution. The steel rebar exposed in 2% inhibitor containing SCP + 3.5 wt.% NaCl solution exhibited 90% inhibition efficiency after 1 h of exposure. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the formation of thermodynamically very stable and sparingly soluble goethite (α-FeOOH), maghemite (γ-Fe2O3), and iron phosphate (FePO4) as passive/oxide film onto the steel rebar surface exposed to 2% inhibitor containing SCP + 3.5 wt.% NaCl solution.

Supplementary cementitious materials (SCMs) and chemical additives (CA) are incorporated to modify the properties of concrete. In this paper, SCMs such as fly ash (FA), ground granulated blast furnace slag (GGBS), silica fume (SF), rice husk ash (RHA), sugarcane bagasse ash (SBA), and tire-derived fuel ash (TDFA) admixed concretes are reviewed. FA (25–30%), GGBS (50–55%), RHA (15–20%), and SBA (15%) are safely used to replace Portland cement. FA requires activation, while GGBS has undergone in situ activation, with other alkalis present in it. The reactive silica in RHA and SBA readily reacts with free Ca(OH)2 in cement matrix, which produces the secondary C-S-H gel and gives strength to the concrete. SF addition involves both physical contribution and chemical action in concrete. TDFA contains 25–30% SiO2 and 30–35% CaO, and is considered a suitable secondary pozzolanic material. In this review, special emphasis is given to the various chemical additives and their role in protecting rebar from corrosion. Specialized concrete for novel applications, namely self-curing, self-healing, superhydrophobic, electromagnetic (EM) wave shielding and self-temperature adjusting concretes, are also discussed.