Ambient Air Humidity Research Articles

The effect of relative air humidity on the evaporation timescales of a human sneeze.

The present paper investigates droplet and aerosol emission from the human respiratory function by numerical and experimental methods, which is analyzed at the worst-case scenario, a violent sneeze without a face covering. The research findings develop the understanding of airborne disease transmission relevant to COVID-19, its recent variants, and other airborne pathogens. A human sneeze is studied using a multiphase Computational Fluid Dynamics (CFD) model using detached eddy simulation coupled to the emission of droplets that break up, evaporate, and disperse. The model provides one of the first experimental benchmarks of CFD predictions of a human sneeze event. The experiments optically capture aerosols and droplets and are processed to provide spatiotemporal data to validate the CFD model. Under the context of large random uncertainty, the studies indicate the reasonable correlation of CFD prediction with experimental measurements using velocity profiles and exposure levels, indicating that the model captures the salient details relevant to pathogen dispersion. Second, the CFD model was extended to study the effect of relative humidity with respect to the Wells curve, providing additional insight into the complexities of evaporation and sedimentation characteristics in the context of turbulent and elevated humidity conditions associated with the sneeze. The CFD results indicated correlation with the Wells curve with additional insight into features, leading to non-conservative aspects associated with increased suspension time. These factors are found to be associated with the combination of evaporation and fluid-structure-induced suspension. This effect is studied for various ambient air humidity levels and peaks for lower humidity levels, indicating that the Wells curve may need a buffer in dry climates. Specifically, we find that the increased risk in dry climates may be up to 50% higher than would be predicted using the underlying assumptions in Wells’ model.

Cerium metal oxidation studied by IR reflection-absorption and Raman scattering spectroscopies

Oxidation of cerium metal is a complex process which is strongly affected by the presence of water vapor in the oxidative atmosphere. Here, we explore, by means of infrared reflection-absorption spectroscopy (IRRAS) and Raman scattering spectroscopies, thin oxide films, formed on cerium metal during oxidation, under dry vs ambient (humid) air conditions (∼0.2% and ∼50% relative humidities, respectively) and compare them with a thin film of CeO2 deposited on a Si substrate. Complementary analysis of the thin films using x-ray diffraction and focused ion beam-scanning electron microscopy enables the correlation between their structure and spectroscopic characterizations. The initial oxidation of cerium metal results in the formation of highly sub-stoichiometric CeO2−x . Under dry air conditions, a major fraction of that oxide reacts with oxygen to form CeO∼2, which is spectroscopically detected by Raman scattering F 2g symmetry mode and by IRAAS F 1u symmetry mode, splitted into doubly-degenerate transverse optic and mono-degenerate longitudinally optic (LO) modes. In contrast, under ambient (humid) conditions, the oxide formed is more heterogenous, as the reaction of CeO2−x diverges towards the dominant formation of Ce(OH)3. Prior to the spectral emergence of Ce(OH)3, hydrogen ions incorporate into the highly sub-stoichiometric oxide, as manifested by Ce–H local vibrational mode detected in the Raman spectrum. The spectroscopic response of the thin oxide layer thus formed is more complex; particularly noted is the absence of the LO mode. It is attributed to the high density of microstructural and compositional defects in the oxide layer, which results in a heterogenous dielectric nature of the thin film, far from being representable by a single phase of CeO∼2.

Friction Behavior and Structural Evolution of Hexagonal Boron Nitride: A Relation to Environmental Molecules Containing -OH Functional Group.

Sliding contact experiments and first-principles calculations were performed to elucidate the roles of environmental molecules containing -OH functional groups on the friction behavior and structural evolution of hexagonal boron nitride (h-BN). A significant decrease in the friction coefficient (COF) is established by the physisorption and dissociative adsorption of molecules containing -OH functional groups on h-BN, compared with that in a H2 or N2 atmosphere. A key finding is the existence of two friction mechanisms to reconstruct the sliding interface for h-BN crystallites in humid air and carbon contaminant (CH3OH and C2H5OH) atmospheres, which is verified by the friction behavior and morphologies of the wear track. There is a running-in period in the friction process to induce the formation of defects in h-BN in humid air, which facilitates dissociative adsorption of water molecules on h-BN. The formation of nanostructured water at defect sites will promote lamellar slip of h-BN crystal materials for friction reduction. In carbon contaminant environments, both molecules exhibit strong adsorption on the h-BN surface regardless of the presence of defects, thereby weakening the structural damage rate and enhancing the bearing capacity. C2H5OH molecules are more likely to dissociate and bind onto defect sites, endowing h-BN with high in-plane stress to form a coiled structure. h-BN in the annular or tubular form would exhibit a self-protective effect, facilitate incommensurate contact, and reduce the contact area to enhance lubrication. Our work may establish the fundamental basis for future applications of h-BN in new energy vehicles.

Effects Of Environmental Factors And Atmospheric Pollution in the Incidence of Hospital Admissions of Patients With Stroke In São Paulo City By Stroke In São Paulo City

Introduction: Stroke is one of the major causes of morbidity and mortality worldwide, difficult to treat and recover. The risk of developing stroke may be associated with environmental factors. Objective: To analyze the association between ambient temperature, air humidity and atmospheric pollution with the incidence of hospital admissions for stroke in the city of São Paulo in 2016. Methods: This is an ecological study, carried out by secondary data collection in the city of São Paulo in 2016. The definition of Stroke was according to the tenth revision of the International Classification of Diseases in codes: I60, I61, I63 and I64. Results: There was a positive correlation between the incidence of hospital admissions for stroke and in SO2 in air (rho: 0.80, p=0002) in women. In men there was a positive correlation between the number of hospital admission and SO2 concentration (rho: 0.570, p=0.005). Conclusion: We observed a positive correlation between the incidence of stroke and the concentration of the atmospheric pollutant SO2, an important fact for the intervention in the dispersion of pollutants.

Enhancing performance and stability of perovskite solar cells through defect passivation with a polyamide derivative obtained from benzoxazine-isocyanide chemistry

• A phenolic hydroxyl-substituted polyamide derivative PAB serves as an passivating agent. • Hole transport polymer PM6-T10 is used in perovskite solar cells for the first time. • Three kinds of polar groups linked by flexible backbone provide effective passivation. • Devices PAB-0.15 display better device performances than the reference devices PAB-0. Owing to the presence of amounts of defects in organic/inorganic hybrid perovskite, defect passivation is considered as a significant way to improve the efficiency and stability of perovskite solar cells (PVSCs). Herein, for the first time, a phenolic hydroxyl-substituted polyamide derivative (PAB), which was prepared by benzoxazine-isocyanide chemistry (BIC) and simultaneously contained hydroxyl, secondary amine, and carboxyl functional segments, was selected as the precursor additive to passivate perovskite active layer. Different passivation groups attached in the chain of a polymer are vital for the defect passivation of perovskite containing various defects. Hydroxyl and carboxyl can act as Lewis bases to passivate the undercoordinated lead defects, and secondary amine can coordinate with iodide ion. These passivation groups linked by the flexible polymer chains provide effective interaction with trap states on the surfaces and grain boundaries of perovskite, suppressing the trap-assisted non-radiative charge carrier recombination thus. As a result, these positive effects increased the efficiency of PVSCs from 19.45% to 21.13%, and maintained 95% initial efficiency after 32 days in ambient air (humidity around 50%, room temperature). This work opens a viable avenue to develop efficient passivating polymers via benzoxazine-isocyanide chemistry.

The Effect of Retrofitted Refrigerant and Environmental Temperature on the Performance of Air Conditioner: An Experimental Study

There are several factors that influence the efforts to increase the performance of an air conditioner (AC), one of which is the selection of working fluid, environmental condition, and device components. Refrigerant is the most vital substance which determines the efficiency of the cooling machine. In addition, ambient air temperature and humidity are other important factors that affect the performance of the cooling machine. Therefore, it is extremely crucial to calculate the environmental condition, which is the air temperature, so that the cooling machine can work optimally. Currently, the refrigeration system uses R-22 refrigerant. However, the use of R-22 has a high ODP (ozone depletion potential) value, thus having a risk of damaging the ozone layer. As a safer alternative, the use of hydrocarbon refrigerants, such as R134a and R290, can solve this problem as they do not have any ODP. This study was conducted by retrofitting the synthetic refrigerant in Air Conditioner (AC) 1 HP with various types of hydrocarbon refrigerant. The outside air temperatures used were 30°C, 50°C, 60°C, and 70°C, while the airflow velocity across the condenser also varied, namely 4.8 m/s, 5.8 m. /s, 6 m/s, and 6.6 m/s. From the results of this study, it is known that retrofitting synthetic refrigerants into hydrocarbon refrigerants can increase the coefficient of performance (COP) of the air conditioner. The uses of R134a and R290 hydrocarbon refrigerants increase the COP by 19% and 24.5%, respectively. In addition, lower ambient temperature will reduce the required electrical power. R290 Refrigerant has the best COP value compared to R22 and R134a.

Performance analysis of a novel double stage multifunctional open absorption heat pump system: An industrial moist flue gas heat recovery application

Rising industrial energy consumption and waste heat in moist flue gas exhausts are the key scientific issues. A potential hybrid system with efficient heat recovery technology can fulfill the industrial energy demand for dehumidification, heating and cooling applications by utilizing the waste latent heat. The main objective of this study is to present a multifunctional hybrid system for double stage open absorption cycle to recover the latent heat from the exhaust moist flue gas for heating and to dehumidify the ambient humid air for cooling applications by operating at low-grade heat source. The validated thermodynamic models for energy and exergy analysis are developed for its performance optimization and to conduct a comparison with single stage system. The operating inlet parameters are varied to analyze the performance of both systems. The parametric study results showed that the double stage system can operate for a wider moist gas humidity range such as 0.054–0.2 kg/kg at lower regeneration heat source of 96.3℃ with varying thermal performance of 1.24–2.39 as compared to the single stage system which operates for 0.118–0.2 kg/kg and at 112.3–153.8℃. Furthermore, this hybrid system is capable to provide heating effect of 280.1 kW at thermal performance of 1.73 and 9.85 kW cooling capacity while operating at 113.7℃ heat source temperature. The thermal performance of system is related to the operating pressure in low pressure generator and can be increased 8–11% when pressure is increased from 25 kPa to 35 kPa. However, the cooling capacity is found to be sensitive only to the absorbers and the dew point cooler. The exergy performance results indicate that the exergy efficiency of double stage system is 3–16% higher as compared to single stage with effect of regeneration temperature and varies from 46.2 to 58.63%. Moreover, the highest exergy destruction is found to be in regenerators which accounts for about 49–51% of overall destructed exergy.

The Effect of Different Cover and Flooring Materials on Climatic Comfort in Landscape Design

In this study, it is aimed to understand the effects of structural and vegetative elements that can be used in landscape designs on the temperature factor, which will greatly affect the climatic comfort, by using artificial neural networks. In this context, measurements were carried out in the morning (08:00-09:00), noon (13:00-14:00) and evening (17:00-18:00) of a total of 100 days, 50 days in each of the winter and summer seasons, at 7 randomly selected points in the Akdeniz University Campus. In these measurements, the temperature difference values of 11 cover elements on 7 different floor covering types were measured, and the ambient air temperature, humidity and wind values were also determined. The temperature differences between the areas where the flooring elements are exposed to direct sun and the shadow effect of different plant and cover elements were determined using an infrared laser thermometer. These values were processed with Neural Designer software and possible temperature difference prediction values were created for 57.750 different alternatives with the help of artificial neural network model from 837 sets of data. Evaluation shows that the maximum temperature difference is 15.6°C at noon in the summer months in the red tartan flooring material and Callistemon viminalis cover material. While the artificial neural network model predicts that there will be a high 2-3° C temperature difference for the alternatives, it has made predictions for temperature differences between 0-10°C in winter and 0-16°C in summer months. Although the temperature differences that will occur in the noon hours are distributed over a wide range of values, it seems that the morning and evening forecasts are concentrated between 0-7°C values. Also, it has been determined that the wind and humidity in the environment are more important factors than the ambient temperature in terms of temperature differences.

METEOROLOGICAL VARIABLES ASSOCIATED WITH SUBARACHNOID HEMORRHAGE: A SINGLE CENTER STUDY.

Spontaneous subarachnoid hemorrhage (SAH) can occur unexpectedly and independently of the classic risk factors. Several different factors could affect intracranial aneurysm (IA) rupture, such as morphological and hemodynamic factors. The aim of this study was to establish the potential association of meteorological data such as temperature, atmospheric pressure, and humidity, and the onset of clinical symptoms preceding hospital admission of patients with acute SAH due to IA rupture. This retrospective study included 130 consecutive patients admitted for non-traumatic SAH with a determinable onset of SAH symptoms. The effects of meteorological parameters of atmospheric pressure, ambient temperature, and relative air humidity on the day of acute SAH onset and 24 hours prior to the onset of symptoms were recorded and analyzed in each patient. Spearman rank correlation analysis was used to assess the risks of incident SAH on the basis of daily meteorological data. Seasonal incidence of acute SAH showed the peak incidence in winter and a trough in summer, with monthly incidence peak in January and December. The circadian rhythm analysis showed the peak incidence of SAH in the forenoon, followed by the evening. Acute SAH incidence showed moderate positive association with daily atmospheric pressure (p<0.05), while no association was found with ambient temperature and relative air humidity. Our results suggested no significant association of changes in ambient temperature and relative humidity with the risk of SAH. Increases in atmospheric pressure were weakly associated with a higher SAH risk. Additional studies are needed to establish in detail both meteorological and morphological factors important to predict IA rupture and SAH.

ALGORITHMIC SUPPORT FOR DECISION-MAKING ON THE EFFICIENCY OF OPERATION OF ABSORPTION AND REFRIGERATION PLANTS OF AMMONIA PRODUCTION

The features of the hardware and technological design of the AM-1360 series ammonia synthesis units operating in Ukraine are established, the main of which is the use of heat-using ammonia-water absorption and refrigeration units in the secondary condensation complex. The analysis of the functioning of the absorption and refrigeration units has been carried out. A significant dependence of their efficiency on external disturbances, such as temperature and humidity of atmospheric air, has been established. This causes significant fluctuations in the cooling temperature of the circulating gas in the evaporators of absorption-refrigeration units, which significantly affects the efficiency of ammonia production in general. Based on the results of the analysis of the existing information system, implemented on the basis of the TDC-3000 microprocessor complex, recommendations for its improvement were developed, the presence of which makes it possible to abandon daily analyzes and carry out only control ones to check measuring instruments.&#x0D; Algorithmic support has been developed, implemented in the MATLAB package and tested according to the data of industrial operation of absorption and refrigeration units of the ammonia synthesis unit. This allows the operator, in real production conditions, to obtain operational information on the numerical indicators of the efficiency of operation of absorption and refrigeration units, which characterize their operation to the greatest extent (circulation rate, cooling capacity, circulating gas cooling temperature and thermal coefficient) and make a decision on the possibility of reducing the cooling temperature. of circulation gas in evaporators by changing the frequency of circulation of solutions The created algorithmic software in the MATLAB environment allows embedding a client module, the so-called OPC client. The latter provides technology for free programming of access to current data.

Effect of ambient air relative humidity on the triboelectric properties of Polypropylene and Polyvinyl Chloride slabs

The humidity of ambient air has always been known to be a major factor in the triboelectric charging of polymers. A study on the influence of this factor was conducted in a climatic test chamber on square-cut Polypropylene (PP) and Polyvinyl Chloride (PVC) plates of dimensions (110 mm × 110 mm x 4.5 mm) rubbed with Aluminum (Al) samples of dimensions (100 mm × 15 mm x 5 mm). The samples were left at least 12 h in the climatic test chamber at fixed temperature (25 °C) and three different values of air relative humidity (20%, 40% and 80%), then rubbed together in a triboelectric charging test bench. The tribocharged PP and PVC samples were then placed under an electrostatic probe to measure the electric potential generated on the surface of the sample. The results of the experiments show that the sign of the tribocharge reverses when the two polymers are exposed to low or high ambient humidity.

Experimental evaluation of an earth–to–air heat exchanger and air source heat pump hybrid indoor air conditioning system

Earth-to-air heat exchanger (EAHE) technology is promising for space heating/cooling. However, in most climates, EAHE alone cannot provide indoor thermal comfort. Hybrid systems combining an EAHE and an air-source heat pump (ASHP) can be used for indoor temperature regulation and energy conservation. We performed full-scale experiments to investigate the hybrid system performance for a building located in a typical hot-summer and cold-winter region of China. Variations in EAHE outlet/indoor air temperature, humidity, cooling/heating loads, energy consumption, and coefficient of performance (COP) were investigated. The results demonstrate a maximum reduction of 14.2 °C during summers and maximum gain of 8.2 °C during winters for the EAHE outlet air temperature, when the air-change rate per hour reaches 16.0. Moreover, the EAHE dehumidifies 1.95 g/kg moisture on average in summer, approximately accounting for 36.2 % of the dehumidification capacity of the hybrid system, with more dehumidification capability for high moisture contents. Compared with an independent ASHP for specific ambient air temperature and humidity ranges, the proposed system exhibits an average energy consumption reduction of 50.91 % and 16.78 %, increases COPASHP by 65.42 % and 11.21 %, and increases COPt by 145.37 % and 82.63 % during the summer and winter periods, respectively.

Visible light boosting hydrophobic ZnO/(Sr0.6Bi0.305)2Bi2O7 chemiresistor toward ambient trimethylamine

Though UV illumination has been widely adopted to activate the room temperature response of metal oxide based chemiresistors, photoexcited abundant carriers (low base resistance) induced low response, and UV induced hydrophilicity caused degradation or even poisoning in ambient humid air atmosphere, pose a challenge for real applications. Herein, 15 mol% (optimized ratio) ZnO nanoparticles have been coupled into hydrophobic (Sr0.6Bi0.305)2Bi2O7 (SBO) matrix, hydrophobic ZnO/SBO chemiresistor has been proposed. Visible 455 nm light could not only trigger the gas/oxide interfacial charge exchange, but also substantially reduce the carrier concentration of chemiresistor in comparison with UV 365 nm light, and therefore noticeably boosts trimethylamine (TMA) response at room temperature, including an enlarged sensitivity, extremely low limit of detection (LoD) (10 ppb), good selectivity, reproducibility and long-term stability. More importantly, present hydrophobic ZnO/SBO chemiresistor could be operated under high relative humidity (RH 90%) with a slight decline (17%) of response with respect to dry air background, opening an opportunity for the practical applications of oxide chemiresistors in ambient humid atmosphere.

Theoretical dehumidification capacity of acorn nutshell-based activated carbon under two Asian urban cities’ ambient air condition

• Prepared activated carbon has better dehumidification performance than silica gel under humid ambient air conditions. • Prepared activated carbon can be utilized as desiccant material with a regeneration temperature of lower than 60°C. • The water isotherm shape of prepared activated carbon gives an advantage to the dehumidification performance. Indoor air humidity plays a vital role in determining occupants’ health and industrial product quality. Removing excess humidity by adsorption dehumidification is still facing a challenge in finding a suitable material with high adsorption capacity and low regeneration temperature. In this study, the theoretical dehumidification capacity of prepared acorn nutshell-based activated carbons was calculated and compared with silica gel type RD and RD-2060. The calculation was based on the outdoor air condition in two Asian capital cities: Jakarta and Tokyo. The theoretical study found that prepared activated carbon has better dehumidification performance under Jakarta conditions using regeneration temperatures of less than 60°C. Under Tokyo conditions, activated carbon shows auspicious performance during the summer season. Compared with silica gels, acorn nutshell-based activated carbon has a better dehumidification capacity to process high humidity ambient air with a lower regeneration temperature.

IoT based Automation of Public Garden and Botanical Garden

People in urban areas appreciate and enjoy the beauty of nature as carefully manicured grass and flowers in public gardens. Senior citizens find this place best for their social networking, while children enjoy their recreational activities here. Botanical garden generally refers to a place where, variety of flora species are planted and grown for the purpose of scientific study. Maintaining a garden or botanical garden takes lot of maintenance effort along with monitoring various parameters such as moisture and light; ambient factors like temperature and humidity of air are also important factors. The focus of this paper is to demonstrate and implement a cost-effective way to monitor and control soil moisture, ambient air temperature and humidity in such gardens by means of controlling drip irrigation pumps and water sprinklers.

Meteorology in field artillery ballistic calculations

The most important meteorological data are:ambient temperature, precipitation quantity, air humidity, amount and type of clouds, atmospheric pressure, wind direction and speed, visibility, weather phenomena. These coefficients impact the effectiveness of various combat activities, especially those conducted in an open space. Knowledge of future weather conditions is essential for planning the location, calculating times, choice of means, and other aspects relevant to the upcoming operations. Taking weather conditions into account is vital, specifically when it comes to planning combat operations, where the accuracy in cooperation is of paramount importance. Rocket forces and artillery is a particular type of armed forces where weather conditions are critical. The effectiveness of artillery depends on ballistic calculation precision, and so knowledge of atmospheric conditions is fundamental. Atmospheric data are collected from sounding using a single probe attached to a balloon. It is generally known that particular meteorological parameters change in a smooth spatial manner depending on various coefficients. Information about the atmosphere collected by a single probe may be insufficient, due to the possibility of a balloon drifting away from the area of interest, and the calculations are based on data received from its probe. In this paper, I will suggest a method for preparing artillery use meteorologically, which takes into account the distribution of particular meteorological coefficients over a given area.

Design and fabrication of multi-functional equipment to produce gaseous nitrogen/oxygen and water from ambient air

Mother earth provides all the necessary resources for the existence of life. Despite the rich resources of water on our planet, majority of world’s total population experiences water shortage annually. Studies have shown that with the increase of global warming, the average humidity of ambient air is rising annually. Due to the decrease of water table on land, alternative sources of acquiring potable water can be of great utility. Out of the several methods available to tap potable water, this paper aims to achieve an alternate source of receiving fresh water directly from ambient air. This process is completely different from distillation. The ambient air also comprises a majority of Nitrogen, and this N2 is used for the purpose of creating an inert environment in packaging industries and for the purpose of extinguishing fire, a multi-functional equipment has been fabricated in order to extract water, along with pure Nitrogen gas from the residual dry air. A Pressure Swing Adsorption (PSA) system is used to separate the Nitrogen from remaining air molecules based on their relative molecular size. In the current industrial sectors, the valves required to actuate the flow of air in PSA system are controlled by PLC circuits and Cam followers. These electro-mechanical components are overpriced. In this work electronic timers are used to actuate the valve timing, which resulted in economical. The system fabricated is simple in construction and it is easy to replace the Carbon Molecular Sieves (CMS) with Zeolite Molecular Sieves in order to obtain Oxygen gas as the pure product that can be used to help Covid-19 patients using medical grade filters. The system can be scaled up with larger mass of CMS, bigger PSA towers and greater compressor power in order to increase productivity.

(Invited) Ambient Storage and Washing of NCMs: Formation/Removal of Surface Contaminants and NCM Structural Changes upon Heating of Washed/Stored NCMs

Cathode active materials (CAMs) based on Ni-rich layered transition metal oxides, like NCMs or NCAs, are commonly subjected to a final washing step in water to remove residual lithium hydroxide and carbonate, which otherwise lead to gelling of the electrode slurry and gassing during cell operation [1,2]. Washing, however, is accompanied by an increase in the pH of the washing solution (the steady-state pH increasing with Ni content), suggesting a Li+/H+ exchange in the near-surface region of the CAM particles, concomitant with the formation LiOH [3,4]. Due to the latter, small amounts of OH-based surface contaminants remain on the surface after washing, while carbonate-based surface contaminants can be removed completely, as shown by XPS [5]. TGA-MS analysis reveals that the incorporation of protons in washed NCMs results in a mass loss at much lower temperatures than in the case of pristine lithiated NCMs; it is accompanied by the release of H2O at ~160 °C and of O2 at ~270 °C, which are ascribed to the formation of spinel- and rocksalt-like surface phases, respectively [3]. These surface processes may be compared to the bulk conversion of layered nickel oxyhydroxide (NiOOH) to the NiO rocksalt phase that initiates at also »160 °C upon the simultaneous release of H2O and O2 [6]. The formation of these oxygen-depleted surface phases can also be confirmed by XPS and soft-XAS [5, 7] and they result in a significant increase of the CAM impedance [3].The Li+/H+ exchange in the near-surface region of layered transition metal oxide CAMs upon washing was also shown to occur upon their storage at humid ambient air [5]. In this case, however, surface contaminants are accumulated on the CAM surface, consisting of LiOH, Li2CO3, and basic nickel carbonates (NiCO3·2Ni(OH)2·xH2O) [8,9,10]. The total amount of these surface contaminants increases with storage time and particularly with Ni content [5], leading to a deterioration of their cycling performance [8,9,10], which we have ascribed to their high reactivity with the electrolyte [10]. Upon heating of NCMs stored at humid air, surface contaminants other than Li2CO3 can be removed up to 450 °C, while the Li+/H+ exchange leads to the formation of oxygen-depleted surface layers within the same temperature range, identical to what was observed for washed NCMs.This presentation will review and summarize the above described phenomena, outlining the differences and the similarities between the NCM surface changes affected by either washing or storage at ambient humid air.

Characteristics of the weather and climatic conditions of the Arctic zone of the Krasnoyarsk Territory by bioclimatic indices

Aim. Assess the health risk of a cold environment by bioclimatic indices characterizing weather and climatic conditions in the Arctic zone of the Krasnoyarsk Territory.Materials and methods. The mean monthly daily ambient temperature, wind speed and relative air humidity were determined. The body cooling conditions integral index (BCCII) and the wind-cold index (WCI) were calculated.Results and their discussion. Using the BCCII from 4 to 6 months a year at Cape Chelyuskin, the critical risk of frostbite in exposed areas of the body determined at Dixon Island from 4 to 5 months a year; in July and August, the indicator values reached the lower border of the “moderate risk”. Using the WCI, an uncomfortable cold environment was determined, respectively, 2 months and 4 months, a very cold — 3 months and 2 months, and an extremely cold — 3 months and 2 months.Conclusion. The advantage of using BCCII rather than WCI is shown, since on its basis the criteria for safe working conditions in an open area are determined. To interpret the value of “no risk” while using WCI, it is necessary to know the period of the year, in which the weather and climatic conditions are assessed as a cold environment.

Cutting Oxygen Production-Related Greenhouse Gas Emissions by Improved Compression Heat Management in a Cryogenic Air Separation Unit.

Oxygen production in cryogenic air separation units is related to a significant carbon footprint and its supply in the medicinal sphere became critical during the recent COVID-19 crisis. An improved unit design was proposed, utilizing a part of waste heat produced during air pre-cooling and intercooling via absorption coolers, to reduce power consumption. Variable ambient air humidity impact on compressed air dryers’ regeneration was also considered. A steady-state process simulation of a model 500 t h−1 inlet cryogenic air separation unit was performed in Aspen Plus® V11. Comparison of a model without and with absorption coolers yielded an achievable reduction in power consumption for air compression and air dryer regeneration by 6 to 9% (23 to 33 GWh year−1) and a favorable simple payback period of 4 to 10 years, both depending on air pressure loss in additional heat exchangers to be installed. The resulting specific oxygen production decrease amounted to EUR 2–4.2 t−1. Emissions of major gaseous pollutants from power production were both calculated by an in-house developed thermal power plant model and adopted from literature. A power consumption cut was translated into the following annual greenhouse gas emission reduction: CO2 16 to 30 kilotons, CO 0.3 to 2.3 tons, SOx 4.7 to 187 tons and NOx 11 to 56 tons, depending on applied fossil fuel-based emission factors. Considering a more renewable energy sources-containing energy mix, annual greenhouse gas emissions decreased by 50 to over 80%, varying for individual pollutants.