Identification of particulate matter is important in assessing an individual’s exposure to potentially harmful particles, such as aeroallergens, toxins, and emissions from combustion sources, which can contribute to cardio-pulmonary diseases. Efficient collection of aerosols is essential for aerosol exposure studies such as analysis of chemical and biological components. We present the design and evaluation of a capillary collector that collects PM2.5 onto the outer surface of a capillary for in-situ spectroscopic analysis. The capillary collector uses a needle-to-ring corona generator to charge particles; the electric field between a cylinder and a wire inserted into the bore of a capillary is used to collect the charged particles. Corona and repelling voltages are optimized for maximum collection of ambient PM2.5 particles and fluorescent polystyrene latex microspheres in the PM2.5 size range, on the capillary. The capillary collection efficiency of ambient PM2.5 at 3 slpm operating flow rate and optimal operating voltages is 63%. Fluorescence spectroscopy is used to quantify the collection of polystyrene latex microspheres. The fluorescence-based capillary collection efficiency is in close agreement with the capillary collection efficiency of ambient PM2.5. The collection and analysis methodology can be used to develop a compact, low-cost sensor for in-situ spectroscopic analysis of aerosols to determine their chemical composition for source apportionment.
The world has been challenged since late 2019 by COVID-19. Higher education institutions have faced various challenges in adapting online education to control the pandemic spread of COVID-19. The present study aims to conduct a survey study through the interview and scrutinizing the literature to find the key challenges. Subsequently, an integrated MCDM framework, including Stepwise Weight Assessment Ratio Analysis (SWARA) and Multiple Objective Optimization based on Ratio Analysis plus Full Multiplicative Form (MULTIMOORA), is developed. The SWARA procedure is applied to the analysis and assesses the challenges to adapt the online education during the COVID-19 outbreak, and the MULTIMOORA approach is utilized to rank the higher education institutions on hesitant fuzzy sets. Further, an illustrative case study is considered to express the proposed idea's feasibility and efficacy in real-world decision-making. Finally, the obtained result is compared with other existing approaches, confirming the proposed framework's strength and steadiness. The identified challenges were systemic, pedagogical, and psychological challenges, while the analysis results found that the pedagogical challenges, including the lack of experience and student engagement, were the main essential challenges to adapting online education in higher education institutions during the COVID-19 outbreak.
An attempt was made to accelerate the flavour development in cheese base with the help of exogenous proteolytic and lipolytic enzymes (1:1 proportion, each at the rate of 0.025% by weight of cheese‐base) and ripening at elevated temperatures (i.e. 20 ± 1 °C) for up to 12 days. To counter the bitterness developed, adjunct cultures were used: viable or attenuated (freeze‐shocked or heat shocked). Study of biochemical characteristics, electrophoretic pattern and sensory evaluation of the product were carried out. An acceptable enzyme‐modified, lightly salted cheese base was obtained using 0.025% each of proteolytic and lipolytic enzymes, along with 5% starter culture and adjuncts followed by ripening up to 12 days. Freeze‐shocked adjunct Lactobacillus helveticus produced enzyme‐modified cheese base with no detectable bitterness. The usage of exogenous enzymes, temperature of ripening, ripening period and interactions amongst these parameters had significant (P < 0.01) influence on all of the biochemical characteristics monitored. 相似文献
Ag/ZnO nano-hetero-junctions were synthesized by an electrochemical route. The optical absorption spectroscopy and photoluminescence studies reveal the reaction mechanism at the junction. Optical absorption spectra indicate presence of well-defined ZnO excitonic feature along with the Ag surface plasmon absorption feature at 400 nm. Moreover, ZnO green photoluminescence appears on junction formation with Ag. Detailed analysis of emission and excitation processes indicate that efficient charge transfer is taking place from ZnO to Ag. Ag is also responsible for creation of levels in the HOMO-LUMO gap of ZnO. This finding may be of relevance so far as p-type doping in ZnO is concerned. 相似文献
The exercising cooperative and interfacial properties of metal oxide and conducting polymer as a sensing material for humidity detection was the focal point of this study. In this piece of work nano sized NiO and its composite with polyaniline has been prepared. The cooperative effects of NiO on stuructural, morphology, humidity sensing behaviour of PANI has been investigated. Prepared materials were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM),UV–VIS spectroscopy and Four probe techniques. The result reveals that the NiO strongly influences on polymer chain, crystallinity, stability, electrical and optical properties of PANI, which improves its viability in technology development. Finally, PANI/NiO was used for electrochemical humidity sensing of a closed atmosphere. The result reveals that 100 times increase in sensitivity of PANI due to the presence of NiO nano particles. Finally, the results indicate that the impact of NiO on PANI makes it promising perspective materials for humidity monitoring of closed chamber with improved sensing parameters over several method and materials. 相似文献
In this study, design and performance analysis is carried out for a 10 kWh metal hydride based hydrogen storage system. The system is equipped with distinctive aluminium hexagonal honeycomb based heat transfer enhancements (HTE) having higher surface area to volume ratio for effective heat transfer combined with low system weight addition. The system performance was studied under different operating conditions. The optimum absorption condition was achieved at 35 bar with water at room temperature as heat transfer fluid where up to 90% absorption was completed in 7200 s. The performance of the reactor was observed to significantly improve upon the addition of the HTE network at a minimal system weight penalty. 相似文献
Sudden cardiac death (SCD) is reported as leading cause of death in patients on chronic hemodialysis. Arrhythmias are proposed to be a major predisposing factor for SCD. However, triggers for potentially lethal arrhythmias are not well understood. Here we describe a case of 72‐year‐old man on chronic hemodialysis via permanent Central venous catheter (CVC) who was admitted for evaluation after unwitnessed fall. Within 10 minutes of his first routine dialysis session in the hospital, he had cardiac‐arrest. He was successfully resuscitated within 3 minutes. The next day, fifteen minutes into the dialysis session, he had bradycardia with telemetry demonstrating long sinus pause and he lost consciousness. After few minutes of Advanced Cardiac Life Support (ACLS) he regained pulse and consciousness. Further review of the chest X‐ray revealed the tip of CVC to be directly touching the distal Superior Vena Cava (SVC) wall. We felt the catheter tip may have migrated after the fall and now is irritating the Sinoatrial node and triggering bradyarrhythmia. Next day, the CVC was exchanged, and the tip was placed higher up in superior vena‐cava. After repositioning, we started him on dialysis under intensive monitoring, and he tolerated well without any arrhythmia. Subsequent dialysis was uneventful. We describe a case of recurrent symptomatic intra‐dialytic bradycardia due to abnormal positioning of CVC that resolved after the repositioning of the catheter. This case in addition to similar case in nondialysis settlings provides additional insights into mechanisms of fatal arrhythmias in hemodialysis patient having CVC. 相似文献