RESUMEN
This study investigates in detail the laser-mediated upconversion emission and temperature-sensing capability of (Ca0.99-a Yb0.01Er a )TiO3. Samples were prepared at different concentrations to observe the effect of erbium on upconversion while increasing its concentration and keeping all the other parameters constant. Doping is a widespread technological process which involves incorporating an element called a dopant in a lower ratio to the host lattice to derive hybrid materials with desired properties. The (Ca0.99-a Yb0.01Er a )TiO3 perovskite nanoparticles were synthesized via a sol-gel technique. The frequency upconversion was performed using a 980 nm laser diode excitation source. X-ray diffractometry (XRD) confirmed that the synthesized samples are crystalline in nature and have an orthorhombic structure. The temperature-sensing ability was examined using the fluorescence intensity ratio (FIR) algorithm of two emission bands (2H11/2 â 4I15/2 and 4S3/2 â 4I15/2) of the Er3+ ion. Temperature-dependent upconversion luminescence is observed over a broad temperature range of 298-623 K. The maximum sensor sensitivity obtained is 6.71 × 10-3 K-1 at 110°.
RESUMEN
The superior hydrogen storage properties makes the KSiH3 system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of the reaction restricts the system to absorb and desorb hydrogen reversibly at elevated temperatures even if the thermodynamics suggest its room temperature operation. Several catalysts have already been tested to enhance its kinetic properties. In this work, the efforts were made to reduce the activation energy by using Zr-based catalysts to the KSi/KSiH3 system. The value of activation energy was found to be lowest (i.e., 87 kJ mol-1) for the ZrH2-added KSiH3 system. The mechanism of this improvement was investigated by using X-ray photoelectron spectroscopy (XPS).
RESUMEN
BACKGROUND: The best way to handle an emergency is to be prepared in advance. The purpose of this study was to assess the availability of medical emergency drugs at dental offices and to determine the level of knowledge and preparedness of dentists to manage medical emergencies at their dental offices. MATERIALS AND METHODS: A descriptive cross-sectional study was conducted from January to June 2014 with 250 dental graduates to determine their knowledge and ability in the management of medical emergencies and assess availability of emergency drugs and equipments in dental offices in the Ahmedabad and Udaipur areas of India. The questionnaire consisted of mainly objective questions, requiring a simple yes or no reply. Mann-Whitney test was used for the analysis. A 95% confidence level was used and a P value of less than or equal to 0.05 was considered statistically significant. RESULTS: The results of our study showed that almost all the surveyed dentists (98%) enquired about medical history, but only 12% obtained filled health history proforma from patients regarding the above. Only 38.4% participants recorded the vital signs of patients before commencing any treatment. Also, 7.6% reported about having attended any workshops on emergency training or management programs. Emergency kits were available with only 24% participants and the available kits were assessed for the availability of emergency drugs. Also, 34% were confident about giving intramuscular injection and only 6.6% were sure about giving intravenous injections. The P value was found to be highly statistically significant. CONCLUSION: The results of our study reflect an alarming situation about the capability of dentists to deal with such conditions.