Simulation of environmental impact of an existing natural gas dehydration plant using a combination of thermodynamic models

A new approach was presented to improve the simulation results of an existing TEG based natural gas dehydration plant, using Aspen Plus software. Furthermore, the environmental impact of the plant was investigated. The plant consists of four main unit operations including an absorber, a flash tank, a stripper and a regenerator

CHANGES IN THE SECONDARY STRUCTURE AND ASSEMBLY OF PROTEINS ON FLUORIDE CERAMIC (CEF3) NANOPARTICLE SURFACES

Fluoride nanoparticles (NPs) are materials utilized in the biomedical field for applications including imaging of the brain. Their interactions with biological systems and molecules are being investigated, but the mechanism underlying these interactions remains unclear. We focused on possible changes in the secondary structure and aggregation state of proteins on the surface of NPs and investigated the principle underlying the changes using the amyloid β peptide (Aβ16−20) based on infrared spectrometry. CeF3 NPs (diameter 80 nm) were synthesized via thermal decomposition. Infrared spectrometry showed that the presence of CeF3 NPs promotes the formation of the β-sheet structure of Aβ16−20. This phenomenon was attributed to the hydrophobic interaction between NPs and Aβ peptides in aqueous environments, which causes the Aβ peptides to approach each other on the NP surface and form ordered hydrogen bonds. Because of the coexisting salts on the secondary structure and assembly of Aβ peptides, the formation of the β-sheet structure of Aβ peptides on the NP surface was suppressed in the presence of NH4 + and NO3 − ions, suggesting the possibility that Aβ peptides were adsorbed and bound to the NP surface. The formation of the β-sheet structure of Aβ peptides was promoted in the presence of NH4 + , whereas it was suppressed in the presence of NO3 − because of the electrostatic interaction between the lysine residue of the Aβ peptide and the ions. Our findings will contribute to comparative studies on the effect of different NPs with different physicochemical properties on the molecular state of proteins

Investigating the energy transition to a coal free residential sector in Kazakhstan using a regionally disaggregated energy systems model

Problems with unsustainable use of energy by households and lack of access to energy infrastructure require effective actions from the policy makers. Energy system models can usefully analyze future residential sector energy pathways "within" the full energy system. However, few energy system models have been developed with disaggregated sub-national regional detail, building type and urban/rural divisions. This paper addresses this key gap. Disaggregating the residential sector by building categories allows improved representation of the range of energy transition options across building categories. We incorporated a novel detailed building stock module into a 16-region TIMES energy systems model for Kazakhstan, using statistical data on the housing stock and building energy audit reports. We then explore the introduction of a coal ban and use scenario analysis to identify the most cost-effective heating technologies for the different regions and different building types. Implications of the residential sector policies to the supply side energy infrastructure were also quantified. The energy transition (from solid fuels to cleaner alternatives) is rarely achievable without Government intervention, therefore scenarios with ban on coal use and clean energy technology subsidies (micro-CHP, heat pumps and solar space heaters) have been investigated in this study. The results indicate that in rural areas networked gas (for detached households) and district heating (for flats) are more economically viable substitutes to coal, even with subsidies offered for clean technologies. In the scenario with the constraint on gas network expansion and clean technology subsidies, there is a wide utilization of heat pumps in detached rural houses. Subsidies for retrofit measures are effective with wide utilization, especially in the areas affected by the coal ban, with up to 76% reduction of the useful energy demand. The total amount of allocated subsidies for clean technologies amounted for up to 32% and 8% of the current state social and health care expenditures. A coal ban in the residential sector is estimated to achieve emissions reductions for PM2.5 and CO of 92% and 95%, respectively (compared to the base year level), even accounting for emissions from the supply side (power plants, heat plants)

Global Air Quality and COVID-19 Pandemic : Do We Breathe Cleaner Air?

The global spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has challenged most countries worldwide. It was quickly recognized that reduced activities (lockdowns) during the Coronavirus Disease of 2019 (COVID-19) pandemic produced major changes in air quality. Our objective was to assess the impacts of COVID-19 lockdowns on groundlevel PM2.5, NO2, and O-3 concentrations on a global scale. We obtained data from 34 countries, 141 cities, and 458 air monitoring stations on 5 continents (few data from Africa). On a global average basis, a 34.0% reduction in NO2 concentration and a 15.0% reduction in PM2.5 were estimated during the strict lockdown period (until April 30, 2020). Global average O-3 concentration increased by 86.0% during this same period. Individual country and continent-wise comparisons have been made between lockdown and business-as-usual periods. Universally, NO2 was the pollutant most affected by the COVID-19 pandemic. These effects were likely because its emissions were from sources that were typically restricted (i.e., surface traffic and non-essential industries) by the lockdowns and its short lifetime in the atmosphere. Our results indicate that lockdown measures and resulting reduced emissions reduced exposure to most harmful pollutants and could provide global-scale health benefits. However, the increased O-3 may have substantially reduced those benefits and more detailed health assessments are required to accurately quantify the health gains. At the same, these restrictions were obtained at substantial economic costs and with other health issues (depression, suicide, spousal abuse, drug overdoses, etc.). Thus, any similar reductions in air pollution would need to be obtained without these extensive economic and other consequences produced by the imposed activity reductions.Peer reviewe

Investigating the impact of different sport trainings on particulate matter resuspension in a sport center using well-characterized reference instruments and a low-cost monitor

Abstract The present study investigated the exposure of teenagers, adults, and students to PM1, PM2.5, PM4, PM10, particle number concentration at two sport facilities of Nazarbayev University including Gymnastics Hall and Multi-purpose Hall. Measurements were conducted during variety of sport training sessions including soccer, basketball, volleyball, Mixed Martial Arts (MMA), boxing, table tennis, etc. A low-cost instrument, Dylos was employed to compare its performance against two TSI instruments. In overall, the Dylos showed acceptable peaks when the source of particle resuspension was present. However, no correlation was observed between Dylos data and Dusttrak fine and coarse particle data. The average PM2,5 and PM10 concentrations were found to be below the WHO limits. The number of participants during the training sessions and sports involving balls including basketball, soccer and volleyball were the two factors responsible for the observed increased particle resuspension

Size segregated PM and its chemical composition emitted from heated corn oil

Abstract Characterization of the airborne particulate matter (PM) emitted from cooking components including cooking oil, and additives like salt has not been carefully investigated. This study provides new data on the concentration, composition, and emission rates/fluxes of PM (less than 3.3µm) generated during heating corn oil and corn oil with added table salt. The concept of emission flux was employed to estimate the emission rates in this study. A statistically significant reduction of 47.6% (P<0.05) in the total PM emission rate and emission flux were observed when salt was added to the heated corn oil (5.15×101mgmin−1) compared to the pure oil (9.83×101mgmin−1). The OC emission rate decreased 61.3% (P<0.05) when salt was added to the corn oil (2.35×101mgmin−1) compared to the pure corn oil (5.83×101mgmin−1). With the salt, the total EC emission rate was 6.99×10−1mgmin−1, a 62.7% reduction in EC emission compared to pure corn oil (1.88mgmin−1). These results suggest that table salt can be added to the corn oil prior to frying to reduce exposure to cooking generated PM

Ambient Benzo[a]pyrene&rsquo;s Effect on Kinetic Modulation of Amyloid Beta Peptide Aggregation: A Tentative Association between Ultrafine Particulate Matter and Alzheimer&rsquo;s Disease

Long-time exposure to ambient ultrafine particles is associated with an increased risk of neurodegenerative diseases such as Alzheimer&rsquo;s disease (AD), which is triggered by the aggregation of A&beta; peptide monomers into toxic oligomers. Among different ultrafine air pollutants, polycyclic aromatic hydrocarbons (PAHs) are known to have a negative neural impact; however, the impact mechanism remains obscure. We herein examined the effect of Benzo[a]Pyrene (B[a]P), one of the typical PAHs on A&beta;42 oligomerization using all-atom molecular dynamics simulations. In particular, the simulations were performed using four molecules of A&beta;42 in the presence of 5.00 mM, 12.5 mM, and 50.0 mM of B[a]P. The results revealed strong hydrophobic interactions between A&beta;42 peptides and B[a]P, which in turn resulted in increased interpeptide electrostatic interactions. Furthermore, 5.00 mM of B[a]P accelerated the kinetics of the formation of peptide tetramer by 30%, and stabilized C-terminus in A&beta;42 peptides, suggesting consequent progression of AD in the presence of 5.00 mM B[a]P. In contrast, 12.5 mM and 50.0 mM of B[a]P decreased interpeptide interactions and H-bonding due to the aggregation of numerous B[a]P clusters with the peptides, suppressing oligomerization kinetics of A&beta;42 peptides by 13% and 167%, respectively. While the study elucidates the effect of small environmental hydrophobic molecules on the formation of A&beta; oligomers, the impact of ambient ultrafine particles on AD in the complex composition of the environmental realm requires further systematic delving into the field

IMPACT OF VOLATILE ORGANIC COMPOUNDS ON CHROMIUM CONTAINING ATMOSPHERIC PARTICULATE: INSIGHTS FROM MOLECULAR DYNAMICS SIMULATIONS

The effect of volatile organic compounds (VOCs) on chromium-containing atmospheric particles remains obscured because of difficulties in experimental measurements. Moreover, several ambiguities exist in the literature related to accurate measurements of atmospheric chromium concentration to evaluate its toxicity. We investigated the interaction energies and diffusivity for several VOCs in chromium (III)-containing atmospheric particles using classical molecular dynamics simulations. We analyzed xylene, toluene, ascorbic acid, carbon tetrachloride, styrene, methyl ethyl ketone, naphthalene, and anthracene in Cr(III) solutions, with and without air, to compare their effects on solution chemistry. The interaction energy between Cr(III) and water changed from 48 to 180% for different VOCs, with the highest change with anthracene and the lowest change with naphthalene. The results revealed no direct interactions between Cr(III) particles and the analyzed volatile organic compounds, except ascorbic acid. Interactions of Cr(III) and ascorbic acid differ significantly between the solution phase and the particulate phase. The diffusion of Cr(III) and all the VOCs also were observed in a similar order of magnitude (~ 10−5 cm2/s). The results can further assist in exploring the variation in chromium chemistry and reaction rates in the atmospheric particles in the presence of VOCs