No abstract

Knowledge on the impact of the exposure to indoor ultrafine particles (UFPs) on the human brain is restricted. Twelve non-atopic, non-smoking, and healthy adults (10 female and 7 male, in average 22 years old) were monitored for brain physiological responses via electroencephalographs (EEGs) during cooking. Frying ground beef meat in sunflower oil using electric stove without ventilation was conducted. UFPs, particulate matter (PM) (PM 1 , PM 2.5 , PM 4 , PM 10), CO 2 , indoor temperature, RH, oil and meat temperatures were monitored continuously throughout the experiments. The UFP peak concentration was recorded to be approximately 2.0 × 10 5 particles/ cm 3. EEGs were recorded before exposure, at end of cooking when PM peak concentrations were observed, and 30 min after the end of the cooking session (post-exposure). Brain electrical activity statistically significantly changed during post-exposure compared to the before exposure, suggesting the translocation of UFPs to the brain, occurring solely in the frontal and temporal lobes of the brain. Study participants older than 25 were more susceptible to UFPs compared to those younger than 25. Also, the brain abnormality was mainly driven by male rather than female study participants. The brain slow-wave band (delta) decreased while the fast-wave band (Beta3) increased similar to the pattern found in the literature for the exposure to smoking fumes and diesel exhaust.

Globally, NO2 and PM2.5 declined while O3 increased during strict lockdown periods.

SUMMARYThis paper presents a comprehensive study of encapsulated phase change materials (PCMs). In order to investigate some synthesis parameters, microencapsulated paraffin with gelatin/gum Arabic wall system was prepared by the complex coacervation method and the performance of these microcapsules was evaluated by optical microscopy and differential scanning calorimetry. Further investigations were carried out on the impact of physical parameters on the melting time by studying the constrained melting transformation of an encapsulated PCM in a spherical shell subjected to a constant temperature media. Results indicate successful production of PCM microcapsules with high melting enthalpy (116 kJ/kg), and the effects of diameter and thermal conductivity on melting time of PCMs were demonstrated.

Highly filled systems, such as dental materials and tires, have some exceptional properties that make them very special for particular scientists and engineers. In this study, the thermal and dynamic properties of highly nanosilica-filled polystyrene were investigated. Thermal study predicts a phase in the filled system, named as adsorbed polymer, that has a different glass transition temperature (T g ) compared with the neat polymer. The adsorbed polymer seems to be responsible for special thermal properties of the highly filled system. The dynamic properties of the filled system are observed to have a similar trend as the thermal behavior at different particle sizes and concentrations, both increasing linearly with the increase of volume fraction of adsorbed polymer. However, at higher volume fractions or for smaller particles, this trend changes and the filler networking mechanism is considered to be the reason for this change. Effect of the filler network is studied through the Han plot and it is found that the contribution of the filler network to the dynamic behavior of the highly filled system increases by reducing the particle size and increasing the particle loading. Beside the particle size and concentration, the effect of filler surface physics on dynamic and thermal behavior of the highly filled system is investigated and it is found that surface modification of the particle surface with nonpolar groups tends to lower T g and volume fraction for the adsorbed phase and lower strength of the filler network. In this work, the samples were prepared using the method of stabilizing suspension in polymer solution. For viscoelastic investigation, the dynamic rheometry in sweep mode was chosen, also for studying the thermal Downloaded from behavior, differential scanning calorimetric tests were performed. In addition, in order to study the structure of filler in low and highly filled samples, atomic force microscopic imaging was employed.

Our knowledge of the effects of exposure to indoor ultrafine particles (sub‐100 nm, #/cm3) on human brain activity is very limited. The effects of cooking ultrafine particles (UFP) on healthy adults were assessed using an electroencephalograph (EEGs) for brain response. Peak ultrafine particle concentrations were approximately 3 × 105 particle/cm3, and the average level was 1.64 × 105 particle/cm3. The average particle number emission rate (S) and the average number decay rate (a+k) for chicken frying in brain experiments were calculated to be 2.82 × 1012 (SD = 1.83 × 1012, R2 = 0.91, p = 0.0013) particles/min, 0.47 (SD = 0.30, R2 = 0.90, p < 0.0001) min−1, respectively. EEGs were recorded before and during cooking (14 min) and 30 min after the cooking sessions. The brain fast‐wave band (beta) decreased during exposure, similar to people with neurodegenerative diseases. It subsequently increased to its pre‐exposure condition for 70% of the study participants after 30 min. The brain slow‐wave band to fast‐wave band ratio (theta/beta ratio) increased during and after exposure, similar to observed behavior in early‐stage Alzheimer's disease (AD) patients. The brain then tended to return to its normal condition within 30 min following the exposure. This study suggests that chronically exposed people to high concentrations of cooking aerosol might progress toward AD.

Tropospheric NO 2 concentrations obtained from the measurements of the Ozone Monitoring Instrument on board the NASA Aura satellite from 2005 to 2016 were studied to identify major NO 2 emission hot spots, trends, and seasonal variations over Kazakhstan. Emission hot spots are observed over the locations of thermal power plants (Ekibastuz) and major urban and industrial regions (Almaty and Shymkent), as well as the capital city (Astana). Some decreasing trends have been observed for NO 2 over Ekibastuz, whereas the regions of Almaty and Shymkent showed increasing trends due to industrial growth. The seasonal pattern of the NO 2 concentration shows a difference between three industrial cities of Almaty, Shymkent, and Ekibastuz versus the rest of Kazakhstan. In these three cities, a NO 2 maximum is found during wintertime, which we attribute to seasonality of emissions associated with electricity production and the longer chemical lifetime of NO 2 in winter. In contrast, in Astana and the rest of Kazakhstan, the NO 2 concentration reaches a maximum in the summer.

Morphology of a nanocomposite, which has indisputable effects on its properties, is determined by its dynamic and thermodynamic conditions. While physical properties of the components of a nanocomposite as well as the interaction between them are the parameters controlling the morphology thermodynamically, their dynamic condition is related to the issues like intensity of mixing and geometry of mixer. In this research, we investigate the mixing process of solution casting method by studying the effects of mixing intensity on the dynamics of the particle structure and hereby its morphology using sedimentation test. In these experiments, mixing is performed at various durations, input energies, and energy types for suspensions containing different particle sizes and concentrations as well as diverse polymer concentrations. We found that increasing mixing time and input energy along with using ultrasonic wave decrease the size of aggregates. Sedimentation test revealed improvements of dispersion and distribution states of suspension by using ultrasonic waves and high shear mixing, respectively. Finally, particle-particle interaction data show increase in the probability of restructuring after mixing with reduction in particle size and increase in particle volume fraction.