RESUMEN
Using Monte Carlo electronic transport simulations, coupled self-consistently with the Poisson equation for electrostatics, we explore the thermoelectric power factor of nanoengineered materials. These materials consist of alternating highly doped and intrinsic regions on the scale of several nanometers. This structure enables the creation of potential wells and barriers, implementing a mechanism for filtering carrier energy. Our study demonstrates that by carefully designing the nanostructure, we can significantly enhance its thermoelectric power factor compared to the original pristine material. Importantly, these enhancements stem not only from the energy filtering effect that boosts the Seebeck coefficient but also from the utilization of high-energy carriers within the wells and intrinsic barrier regions to maintain relatively high electronic conductivity. These findings can offer guidance for the design and optimization of new-generation thermoelectric materials through improvements in the power factor.
RESUMEN
Thermoelectric (TE) materials can have a strong benefit to harvest thermal energy if they can be applied to large areas without losing their performance over time. One way of achieving large-area films is through hybrid materials, where a blend of TE materials with polymers can be applied as coating. Here, we present the development of all solution-processed TE ink and hybrid films with varying contents of TE Sb2Te3 and Bi2Te3 nanomaterials, along with their characterization. Using (1-methoxy-2-propyl) acetate (MPA) as the solvent and poly (methyl methacrylate) as the durable polymer, large-area homogeneous hybrid TE films have been fabricated. The conductivity and TE power factor improve with nanoparticle volume fraction, peaking around 60-70% solid material fill factor. For larger fill factors, the conductivity drops, possibly because of an increase in the interface resistance through interface defects and reduced connectivity between the platelets in the medium. The use of dodecanethiol (DDT) as an additive in the ink formulation enabled an improvement in the electrical conductivity through modification of interfaces and the compactness of the resultant films, leading to a 4-5 times increase in the power factor for both p- and n-type hybrid TE films, respectively. The observed trends were captured by combining percolation theory with analytical resistive theory, with the above assumption of increasing interface resistance and connectivity with polymer volume reduction. The results obtained on these hybrid films open a new low-cost route to produce and implement TE coatings on a large scale, which can be ideal for driving flexible, large-area energy scavenging technologies such as personal medical devices and the IoT.
RESUMEN
BACKGROUND: Dental education can be a critical wellspring of stress among dental students, and studies have observed higher levels of stress among dental students than in the all-inclusive community. The present study aims to evaluate the perceived stress among dental undergraduate students, the sources of stress, and an association of perceived stress with sociodemographic characteristics and various stressors. MATERIALS AND METHODS: A cross-sectional study was conducted among 380 undergraduate dental students (from 1st year to final year) in a private dental college, Kanpur. A self-administered questionnaire was used to collect data regarding sociodemographic profile, perceived stress using Perceived Stress Scale-14, and academic, psychosocial, and environmental stressors. Data were analyzed using IBM SPSS Statistics-Version 21 (IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0, Armonk, NY, USA: IBM Corp.). RESULTS: The mean perceived stress score was 30.25 ± 1.914. The median perceived stress score was 30. Statistically significant (P < 0.001) values were found for higher age group and year of studying Bachelor of Dental Surgery (BDS) were important sociodemographic determinant of stress. Vastness of academic curricula, frequency of examination (P < 0.05), and fear of failure/poor performance in examinations were important academic determinants of stress. High parental expectations and family problems were important psychosocial stressors. Accommodation away from home was an important predictor of stress (P < 0.001). CONCLUSION: This study revealed that there are various sociodemographic (age and year of study in BDS), academic (curricula, frequency of examination, and performance level) determinants and predictors of stress (type of accommodation), along with psychosocial stressors (parental expectation and family problems). Dental colleges should develop stress management programs to promote gender and social equity and strategies to improve psychological support services. The stress management programs reported either helped to reduce the number of stressors or enhance stress coping skills, using relaxation techniques such as deep breathing, yoga, and stress management programs.
RESUMEN
BACKGROUND: The International Agency for Research on Cancer has predicted that India's incidence of cancer will increase from 1 million in 2012 to more than 1.7 million in 2035. Lack of knowledge about oral cancer among general dental practitioners leads to delay in the diagnosis and treatment of such lesions. The aim of the present study was to investigate the awareness and knowledge of prevention and early diagnosis of oral cancer among dental undergraduate students. MATERIALS AND METHODS: A cross-sectional questionnaire study was conducted. A total of 139 undergraduate students who received teaching on oral diseases including oral cancer in their clinical postings in the department of oral medicine and radiology were included in the study. All the students were subjected to evaluation using structured questionnaires with multiple choices. Data collected were subjected to statistical analysis using the Statistical Package for the Social Sciences (SPSS) software version 18. Chi-square test was done to evaluate the statistical significance. RESULTS: The present study showed that the participants had average awareness and knowledge of oral cancer and its clinical presentations. The awareness and knowledge toward oral cancer protocols revealed a decreasing trend from final-year students to 3rd-year and interns. Nearly 66.2% of the undergraduates felt less well informed regarding oral cancer. All the undergraduates (100%) requested further information about oral cancer. CONCLUSION: The present study concluded that knowledge and awareness of undergraduate dental students with respect to early detection and prevention of oral cancer was satisfactory. It is recommended that the syllabus of dental courses should be expanded to provide knowledge regarding the prevention and early diagnosis of oral cancer.