Enhanced photodegradation of methylene blue by silica coated ZnSe nanoparticles

Herein, we report synthesis of silica-coated ZnSe nanoparticles (SZNPs), by varying the mass to volume ratio of ZnSe : TEOS i.e. mass to mass ratio of ZnSe : SiO2 ranging from 0.0267 to 0.1071. These SZNPs showed enhanced photodegradation of methylene blue (MB) solution under visible light. Silica coating on ZnSe NPs  reduces the toxicity concerns for its wide use as photocatalyst. XRD of bare ZnSe NPs confirms hexagonal crystal structure, and TEM depicts size range of SZNPs around 7 nm. FTIR and Raman measurements confirm the presence of different chemical and silanol groups attached to bare ZnSe and SZNPs. Optical absorption and photoluminescence (PL) show a red shift due to silica coating on ZnSe NPs compared to bare ZnSe. This is due to silanization of ZnSe, as silica shell reduces the recombination of photon-generated electron and hole pairs. Photocatalytic experiments on methylene blue (MB) by bare and SZNPs have been conducted, optimal SZNPs i.e. 0.0535 sample (mass ratio of ZnSe:SiO2) exhibits enhanced photo-generated free radicals. An increase in photodegradation of SZNPs, i.e. from 35 to 46% has been observed compared to bare counterparts (ZnSe). Stability decreased by only 7% after 4th cycle of reuse, depicting efficacy of the SZNPs photocatalyst in the degradation of MB. A pseudo-first-order reaction kinetics has been observed for photodegradation of MB with highest rate constant of 8.6 × 10-3 min-1 for SZNPs (1.0000:0.0535) sample

TinyML based Deep Learning Model for Activity Detection

Our physical and emotional well-being are directly impacted by our body positions. In addition to promoting a confident, upright image, maintaining good body posture during various activities also ensures that our musculoskeletal system is properly aligned. On the other side, bad posture can result in a number of musculoskeletal conditions, discomfort, and reduced productivity. Accurate systems that can detect posture in real time, activity detection, are required due to the rising use of wearable technology and the growing interest in health and fitness tracking. The goal of this project is to create a TinyML model for wearable activity detection that will allow users to assess their posture and make necessary corrections in order to improve their health and general well-being. The project intends to contribute to the creation of useful posture detection technologies that can be quickly implemented on wearable devices for widespread usage by leveraging machine learning algorithms and wearable sensor data. For reliable posture categorization, the model architecture combines deep neural networks (DNN) and LSTM layers. With the development and implementation of the TinyML model, a significant decrease in the model's power consumption, memory, and latency was achieved without any compromise in the accuracy. This work can be used in the fields of health, wellness, rehabilitation, corporate life, sports and fitness to keep track of calories burned, activity duration, distance traveled, posture analysis, and real-time tracking

Synthesis, characterization and optical properties of CdSe/CdS and CdSe/ZnS core-shell nanoparticles

Controlled organic synthesis method used for the preparation of cadmium selenide (CdSe) quantum dots, which are covered with cadmium sulfide (CdS) and zinc sulfide (ZnS) using TOP mediated has been presented in this paper. The size, shape, internal structure, chemical composition and functional groups of the core-shell nanoparticles were analyzed using X-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive spectra and FTIR. These studies show that the particle size is in 2-10 nm range with hexagonal phase. The optical properties were analyzed through UV-visible spectroscopy, photoluminescence spectroscopy and micro-Raman spectroscopy. Photoluminescence blue shift and broadening of Raman spectrum further confirm the narrow size of particles

Metal Doping in Topological Insulators- A Key for Tunable Generation of Terahertz

The unique surface edge states make topological insulators a primary focus among different applications. In this article, we synthesized a large single crystal of Niobium(Nb)-doped Bi2Se3 topological insulator (TI) with a formula Nb0.25Bi2Se3. The single crystal has characterized by using various techniques such as Powder X-ray Diffractometer (PXRD), DC magnetization measurements, Raman, and Ultrafast transient absorption spectroscopy (TRUS). There are (00l) reflections in the PXRD, and Superconductivity ingrown crystal is evident from clearly visible diamagnetic transition at 2.5K in both FC and ZFC measurements. The Raman spectroscopy is used to find the different vibrational modes in the sample. Further, the sample is excited by a pump of 1.90 eV, and a kinetic decay profile at 1.38 eV is considered for terahertz analysis. The differential decay profile has different vibrations, and these oscillations have analyzed in terms of terahertz. This article not only provides evidence of terahertz generation in Nb-doped sample along with undoped sample but also show that the dopant atom changes the dynamics of charge carriers and thereby the shift in the Terahertz frequency response. In conclusion, a suitable dopant can be used as a processor for the tunability of terahertz frequency in TI.Comment: 16 Pages Text + Figs: Comments/suggestions welcom

Head and trunk kinematics and kinetics in normal and cerebral palsy gait: a systematic review.

Background: Cerebral palsy (CP) is a neuromuscular disability characterised by a persistent disorder of movement and posture due to a non-progressive lesion in a developing brain. In children with CP, gait is compromised in a variety of ways. A number of studies have suggested that there is a higher degree of biomechanical variations including kinematics and kinetics at head and trunk while analysing a CP gait. Since coordinated movements of head and trunk are important to analyse a typical gait, it is important to determine these biomechanical changes among children with CP for altered movements such as decreased head and trunk stability. Studies have also reported a variety of outcome measures for clinical use. However, the results among the studies are not consistent as there is variability for altered biomechanics based on type and level of the disorder which requires further investigation. Although clinically very useful, the data regarding the head and trunk biomechanics in children with CP is limited. In this study, a systematic review was done to determine the head and trunk kinematic and kinetics variations in CP gait compared to TD children of the same age-group. Methodology: Scientific articles were obtained by a search in databases including Science Direct, Cinahl, Springer Link, Sport discuss, Web of Science and Pubmed. Limitations used were AND/OR. Full-text articles from 1999 to 2017 in English were selected. Results: A total of 3029 records were identified that included Science Direct (n=1854), Cinahl (n=176), Springer Link (n=121), Sports Discuss (n=101), Web of Science (n=14) and Pubmed (n=763). After removing the duplicates, 1786 records were obtained. Fifty-one full text articles were selected for the eligibility and 27 were included in the study. Conclusions: In this review study, we conclude that children with CP have a significant difference in head and trunk kinetics and kinematics compared to age-matched TD children