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We developed an integrated device composed of a single-probe Electroencephalogram (EEG) and Charge Coupled Device (CCD) based motion sensors for objective measurement of Attention-deficit Hyperactivity Disorder (ADHD). While the measurement of attention-deficit hyperactivity disorder (MAHD) relies on the EEG signal for the assessment of attention during a given structured task, the CCD sensor depicts the movement pattern of the subjects engaged in a continuous performance task. A statistical analysis of attention and movement patterns was performed, and the accuracy of completed tasks was analyzed using indigenously developed software. The device with the embedded software is intended to improve certainty with criterion E. We used the EEG signal from a single-channel dry sensor placed on the frontal lobe of the head of the subjects (3–5 year old pre-schoolers). During the performance of the task power for delta and beta, EEG waves from the subjects are found to be correlated with relaxation and attention/cognitive load conditions. While the relaxation condition of the subject hints at hyperactivity, a more direct CCD-based motion sensor is used to track the physical movement of the subject engaged in a continuous performance task. We used our indigenously developed software for statistical analysis to derive a scale for the objective assessment of ADHD. We also compared our scale with clinical ADHD evaluations and found a significant correlation between the objective assessment of the ADHD subjects and the clinician’s conventional evaluation. MAHD, the integrated device, is supposed to be an auxiliary tool to improve the accuracy of ADHD diagnosis by supporting greater criterion E certainty.

The current COVID-19 pandemic has increased the use of facial masks globally, which of late have registered their presence as a part of our civilization. The N95 mask is one of the most popular choices under the current situation. However, the available masks cannot provide breathing comfort for an extended period, which results in rebreathing of exhaled air that is CO2 rich, and which remains in the breathing space of the respirator. Furthermore, problems like moisture settlement on the covered area of the face due to the multiple layers of fabric-like material causes significant discomfort. Hence, the need for a mask with an air-purification activity is the need of the hour. The present innovation relates to the invention of a mask that is battery-powered or solar-operated and addresses the aforementioned problems. This mask not only regulates the airflow, which is beneficial to our body in every way, but also lowers the discomfort of sweating and heating. The effect of the addition of the self-developed active respirator to the commercially available masks on the inspired CO2 level, thermal comfort, and speech clarity has been demonstrated in this study. We have exhibited through in vitro experiments that the filtration capability of the active-respirator improvised mask, we call the Bose shield, does not deter from that of the standard N95 mask. To our understanding, the use of this novel mask can reduce the occurrence of CO2 rebreathing in respiratory protective devices and its impact on workers who inevitably wear them for a prolonged period of time.

The measurement of mechanical properties of rocks is an essential task to be carried out during the projects involving the rock engineering activities such as civil constructions, tunneling, excavations etc. Although the quantification of uniaxial compressive strength in the laboratory is much faithful, the availability of rock samples and their preparation according to ISRM standards is the major limitation. In this experimental investigation, the quantification of the uniaxial compressive strength (UCS) of rocks using the measurement while drilling (MWD) technique was attempted. During the drilling of dissimilar strength rocks for various combinations of drilling operational parameters, the value of thrust and torque were collected using the digital type drilling dynamometer. The prediction of the UCS was performed by developing a mathematical model considering the parameters used for operating the machine and corresponding thrust and torque values. The prediction capacity of developed model was evaluated using the value account for (VAF), root mean square error (RMSE) and mean absolute percentage error (MAPE). From the results it was concluded that the MWD technique could be a prominent tool for estimation of rock strength properties in future.

Tuning of the photoluminescence emission over a wider range of optical telecommunication wavelength (1.38 μm–1.68 μm) has been achieved by employing a GaAs1 − xSbx capping layer to the strain coupled bilayer InAs quantum dot (QD) heterostructures. It is shown that the modulation of strain between the two dot layers through variation in Sb-content and thickness of the capping layer strongly influence the dot size. The band alignment transformation from type-I to type-II is observed for high Sb-content in the capping layers. In addition, the carrier lifetime is improved by a factor of three in the QD heterostructures having type-II band alignment. This, we believe, is of importance for optoelectronic device applications.

The carrier dynamics study of emerging near infrared (NIR) absorbing materials is an essential need to develop device technology toward enhanced NIR light harvesting. In this study, we have documented the design of an indigenously developed time correlated single photoncounting (TCSPC) system working in the NIR (900 nm-1700 nm) spectral region. The system is compatible to study transient photoluminescence of device samples under tunable bias voltages. The liquid nitrogen cooling and electrical heating of the sample chamber provides additional flexibility of temperature dependent study starting from -196 °C to 400 °C. As a model system to study, we have chosen a multilayer InAs/InGaAs/GaAs/AlGaAs dot in the dual well device sample as the thin film quantum dot heterostructures are of huge relevance in various NIR harvesting devices. We have investigated the detail carrier dynamics of the device sample using the transient photoluminescence upon varying temperature (80 K-300 K), varying emission energy and different bias voltages (0 V-15 V). The critical temperature (160 K) and critical bias (12 V) of achieving longest excited state lifetime has been mechanistically explained using various competing photophysical phenomena such as hole diffusion, energy relaxation, etc. The emission wavelength dependent study at below and above critical temperature further provides an insight into the dominance of carrier capture and thermal escape at the two different temperature zones. Along with the detail understanding of the carrier dynamics, the results can be helpful to get an idea of the electrical stability of the device and the operability temperature as well. The reasonable good resolution of the NIR TCSPC system and considerable good results ensure the future application of the same for other devices also.

A noninvasive or minimally invasive optical approach for theranostics, which would reinforce diagnosis, treatment, and preferably guidance simultaneously, is considered to be major challenge in biomedical instrument design. In the present work, we have developed an evanescent field-based fiber optic strategy for the potential theranostics application in hyperbilirubinemia, an increased concentration of bilirubin in the blood and is a potential cause of permanent brain damage or even death in newborn babies. Potential problem of bilirubin deposition on the hydroxylated fiber surface at physiological pH (7.4), that masks the sensing efficacy and extraction of information of the pigment level, has also been addressed. Removal of bilirubin in a blood-phantom (hemoglobin and human serum albumin) solution from an enhanced level of 77 μM/l (human jaundice >50 μM/l) to ∼30 μM/l (normal level ∼25 μM/l in human) using our strategy has been successfully demonstrated. In a model experiment using chromatography paper as a mimic of biological membrane, we have shown efficient degradation of the bilirubin under continuous monitoring for guidance of immediate/future course of action.

Wide band gap metal oxide semiconductors such as zinc oxide (ZnO) show visible band photolysis that has been employed, among others, to degrade harmful organic contaminants into harmless mineral acids. Metal oxides show enhanced photocatalytic activity with the increase in electronic defects in the crystallites. By introducing defects into the crystal lattice of ZnO nanoparticles, we observe a redshift in the optical absorption shifting from the ultraviolet region to the visible region (400-700 nm), which is due to the creation of intermediate defect states that inhibit the electron hole recombination process. The defects were introduced by fast nucleation and growth of the nanoparticles by rapid heating using microwave irradiation and subsequent quenching during the precipitation reaction. To elucidate the nature of the photodegradation process, picosecond resolved time correlated single photon count (TCSPC) spectroscopy was carried out to record the electronic transitions resulting from the de-excitation of the electrons to their stable states. Photodegradation and TCSPC studies showed that defect engineered ZnO nanoparticles obtained through fast crystallization during growth lead to a faster initial degradation rate of methylene blue as compared to the conventionally synthesized nanoparticles.