scholarly journals On the effect of water-soluble compounds removal on EC quantification by TOT analysis in aerosol samples

2011 ◽  
Vol 11 (7) ◽  
pp. 19851-19880 ◽  
Author(s):  
A. Piazzalunga ◽  
V. Bernardoni ◽  
P. Fermo ◽  
G. Valli ◽  
R. Vecchi
Keyword(s):  
Hot Spots ◽  
Inorganic Compounds ◽  
Water Soluble ◽  
Maximum Temperature ◽  
Temperature Step ◽  
Urban Background ◽  
Real Samples ◽  
Po Valley ◽  
Lower Temperature ◽  
Heavily Polluted Area

Abstract. In this work, three different thermal protocols were tested on untreated and water-washed aerosol samples to study the influence of soluble organic and inorganic compounds on EC measurements. Moreover, analyses on the water soluble extracts were carried out. The aim was to find out the most suitable protocol to analyse samples collected in a heavily polluted area. Indeed, the tests were performed on real samples collected at an urban background station in the Po Valley, which is one of the main pollution hot-spots in Europe. The main differences among the tested protocols were the maximum temperature of the He step (i.e. 870 °C, 650 °C, and 580 °C) and the duration of the plateaus during the heating procedure. Our measurements evidenced the presence of a significant amount of weakly light-absorbing aerosol evolving during the highest temperature step in He (i.e. 870 °C), which makes lower temperature protocols not suitable for EC determination in samples collected in heavily polluted areas like Milan.

scholarly journals Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

2011 ◽  
Vol 11 (19) ◽  
pp. 10193-10203 ◽  
Author(s):  
A. Piazzalunga ◽  
V. Bernardoni ◽  
P. Fermo ◽  
G. Valli ◽  
R. Vecchi
Keyword(s):  
Hot Spots ◽  
Inorganic Compounds ◽  
Technical Note ◽  
Water Soluble ◽  
Carbonaceous Aerosol ◽  
Maximum Temperature ◽  
Urban Background ◽  
Po Valley ◽  
Lower Temperature ◽  
Heavily Polluted Area

Abstract. In this work, three different thermal protocols were tested on untreated and water-washed aerosol samples to study the influence of soluble organic and inorganic compounds on EC measurements. Moreover, analyses on the water soluble extracts were carried out. The aim was to find out the most suitable protocol to analyse samples collected in a heavily polluted area. Indeed, the tests were performed on real samples collected at an urban background station in the Po Valley, which is one of the main pollution hot-spots in Europe. The main differences among the tested protocols were the maximum temperature of the He step (i.e. 870 °C, 650 °C, and 580 °C) and the duration of the plateaus during the heating procedure. Our measurements evidenced the presence of a significant amount of weakly light-absorbing carbonaceous aerosol evolving during the highest temperature step in He (i.e. 870 °C), which makes lower temperature protocols not suitable for EC determination in samples collected in heavily polluted areas like Milan.

scholarly journals An accelerated and effective synthesis of zinc borate from zinc sulfate using sonochemistry

2020 ◽  
Vol 43 (1) ◽  
pp. 7-14
Author(s):  
Ali Can Ersan ◽  
Azmi Seyhun Kipcak ◽  
Meral Yildirim Ozen ◽  
Nurcan Tugrul
Keyword(s):  
Inorganic Compounds ◽  
Zinc Borate ◽  
High Yield ◽  
X Ray Diffraction ◽  
Ultrasonic Probe ◽  
Minimum Particle Size ◽  
Effective Synthesis ◽  
Ft Ir ◽  
Lower Temperature ◽  
Borate Compound

AbstractRecently, sonochemistry has been used for the synthesis of inorganic compounds, such as zinc borates. In this study using zinc sulphate heptahydrate (ZnSO4·7H2O) and boric acid (H3BO3) as starting materials, a zinc borate compound in the form of Zn3B6O12·3.5H2O was synthesized using an ultrasonic probe. Product’s characterization was carried out with using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. Zinc borate compound’s chemical bond structure was observed with Raman and FTIR. From the XRD results it was seen that Zn3B6O12·3.5H2O can be quickly synthesized upon heating at 80°C and 85°C (55 min) or 90°C (45 min) in very high yield (>90%). The minimum particle size obtained was ~143 μm from the SEM results. Zinc borate compound was synthesized at a lower temperature in less time than other synthesized zinc metal compound in literature.

scholarly journals Fog scavenging of organic and inorganic aerosol in the Po Valley

2014 ◽  
Vol 14 (4) ◽  
pp. 4787-4826 ◽  
Author(s):  
S. Gilardoni ◽  
P. Massoli ◽  
L. Giulianelli ◽  
M. Rinaldi ◽  
M. Paglione ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Black Carbon ◽  
Functional Group ◽  
Group Composition ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Carbonaceous Aerosol ◽  
Model Description ◽  
Po Valley ◽  
Scavenging Efficiency

Abstract. The interaction of aerosol with atmospheric water affects the processing and wet removal of atmospheric particles. Understanding such interaction is mandatory to improve model description of aerosol lifetime and ageing. We analyzed the aerosol-water interaction at high relative humidity during fog events in the Po Valley, in the framework of the ARPA-ER Supersite project. For the first time in this area, the changes in particle chemical composition caused by fog are discussed along with changes in particle microphysics. During the experiment, 14 fog events were observed. The average mass scavenging efficiency was 70% for nitrate, 68% for ammonium, 61% for sulfate, 50% for organics, and 39% for black carbon. After fog formation, the interstitial aerosol was dominated by particles smaller than 200 nm Dva (vacuum aerodynamic diameter) and enriched in carbonaceous aerosol, mainly black carbon and water insoluble organic aerosol (WIOA). For each fog event, the size segregated scavenging efficiency of nitrate and organic aerosol (OA) was calculated by comparing chemical species size distribution before and after fog formation. For both nitrate and OA, the size segregated scavenging efficiency followed a sigmoidal curve, with values close to zero below 100 nm Dva and close to 1 above 700 nm Dva. OA was able to affect scavenging efficiency of nitrate in particles smaller than 300 nm Dva. A linear correlation between nitrate scavenging and particle hygroscopicity (κ) was observed, indicating that 44–51% of the variability of nitrate scavenging in smaller particles (below 300 nm Dva) was explained by changes in particle chemical composition. The size segregated scavenging curves of OA followed those of nitrate, suggesting that organic scavenging was controlled by mixing with water-soluble species. In particular, functional group composition and OA elemental analysis indicated that more oxidized OA was scavenged more efficiently than less oxidized OA. Nevertheless, the small variability of organic functional group composition during the experiment did not allow us to discriminate the effect of different organic functionalities on OA scavenging.

scholarly journals Evaluation of three new surface irrigation parameterizations in the WRF-ARW v3.8.1 model: the Po Valley (Italy) case study

2020 ◽  
Vol 13 (7) ◽  
pp. 3179-3201
Author(s):  
Arianna Valmassoi ◽  
Jimy Dudhia ◽  
Silvana Di Sabatino ◽  
Francesco Pilla
Keyword(s):  
Potential Evapotranspiration ◽  
Mediterranean Area ◽  
Maximum Temperature ◽  
Surface Irrigation ◽  
Start Time ◽  
Near Surface ◽  
Local Climate ◽  
Po Valley ◽  
Soil Variables ◽  
Water Amount

Abstract. Irrigation is a method of land management that can affect the local climate. Recent literature shows that it affects mostly the near-surface variables and it is associated with an irrigation cooling effect. However, there is no common parameterization that also accounts for a realistic water amount, and this factor could ascribe one cause to the different impacts found in previous studies. This work aims to introduce three new surface irrigation parameterizations within the WRF-ARW model (v3.8.1) that consider different evaporative processes. The parameterizations are tested on one of the regions where global studies disagree on the signal of irrigation: the Mediterranean area and in particular the Po Valley. Three sets of experiments are performed using the same irrigation water amount of 5.7 mm d−1, derived from Eurostat data. Two complementary validations are performed for July 2015: monthly mean, minimum, and maximum temperature with ground stations and potential evapotranspiration with the MODIS product. All tests show that for both mean and maximum temperature, as well as potential evapotranspiration simulated fields approximate observation-based values better when using the irrigation parameterizations. This study addresses the sensitivity of the results to human-decision assumptions of the parameterizations: start time, length, and frequency. The main impact of irrigation on surface variables such as soil moisture is due to the parameterization choice itself affecting evaporation, rather than the timing. Moreover, on average, the atmosphere and soil variables are not very sensitive to the parameterization assumptions for realistic timing and length.

scholarly journals The impact of biomass burning and aqueous-phase processing on air quality: a multi-year source apportionment study in the Po Valley, Italy

2019 ◽  
Author(s):  
Marco Paglione ◽  
Stefania Gilardoni ◽  
Matteo Rinaldi ◽  
Stefano Decesari ◽  
Nicola Zanca ◽  
...  
Keyword(s):  
Air Quality ◽  
Source Apportionment ◽  
Biomass Burning ◽  
Organic Aerosol ◽  
Cold Season ◽  
World Health ◽  
Rural Site ◽  
Urban Site ◽  
Urban Background ◽  
Po Valley

Abstract. The Po Valley (Italy) is a well-known air quality hotspot characterized by Particulate Matter (PM) levels well above the limit set by the European Air Quality Directive and by the World Health Organization, especially during the colder season. In the framework of the Emilia-Romagna regional project SUPERSITO, the southern Po Valley submicron aerosol chemical composition was characterized by means of High-Resolution Aerosol Mass Spectroscopy (HR-AMS) with the specific aim of organic aerosol (OA) characterization and source apportionment. Eight intensive observation periods (IOPs) were carried out over four years (from 2011 to 2014) at two different sites (Bologna, BO, urban background and San Pietro Capofiume, SPC, rural background), to characterize the spatial variability and seasonality of the OA sources, with a special focus on the cold season. On the multi-year basis of the study, the AMS observations show that OA accounts for an average 45 ± 8 % (ranging 33–58 %) and 46 ± 7 % (ranging 36–50 %) of the total non-refractory submicron particle mass (PM1-NR) at the urban and at the rural site, respectively. Primary organic aerosol (POA) comprises biomass burning (23 ± 13 % of OA) and fossil fuel (12 ± 7 %) contributions with a marked seasonality in concentration. As expected, the biomass burning contribution to POA is more significant at the rural site (urban/rural concentrations ratio of 0.67), but it is also an important source of POA at the urban site during the cold season, with contributions ranging from 14 to 38 % of the total OA mass. Secondary organic aerosol (SOA) contribute to OA mass to a much larger extent than POA at both sites throughout the year (69 ± 16 % and 83 ± 16 % at urban and rural, respectively), with important implications for public health. Within the secondary fraction of OA, the measurements highlight the importance of biomass burning ageing products during the cold season, even at the urban background site. This biomass burning SOA fraction represents 14–44 % of the total OA mass in the cold season, indicating that in this region a major contribution of combustion sources to PM mass is mediated by environmental conditions and atmospheric reactivity. Among the environmental factors controlling the formation of SOA in the Po Valley, the availability of liquid water in the aerosol was shown to play a key role in the cold season. We estimate that organic fraction originating from aqueous reactions of biomass burning products (bb-aqSOA) represents 21 % (14–28 %) and 25 % (14–35 %) of the total OA mass and 44 % (32–56 %) and 61 % (21–100 %) of the SOA mass at the urban and rural sites, respectively.

scholarly journals Soluble Inorganic Arsenic Species in Atmospheric Submicron Particles in Two Polish Urban Background Sites

2020 ◽  
Vol 12 (3) ◽  
pp. 837
Author(s):  
Katarzyna Nocoń ◽  
Wioletta Rogula-Kozłowska ◽  
Grzegorz Majewski ◽  
Patrycja Rogula-Kopiec
Keyword(s):  
Inductively Coupled Plasma ◽  
High Performance ◽  
Road Traffic ◽  
Winter Season ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Water Soluble ◽  
Submicron Particles ◽  
Traffic Emission ◽  
Urban Background

This paper presents results of the research on soluble inorganic As(III) and As(V) bound to submicron atmospheric particles (PM1) in two Polish urban background sites (Zabrze and Warsaw). The purpose of the research was to give some insight on the susceptibility to leaching of PM1-bound arsenic species from easily water-soluble compounds, i.e., considered potentially bioavailable based on its daily and seasonal changes. Quantitative analysis for 120 PM1 samples (collected from 24 June 2014 to 8 March 2015) was performed by using a high-performance liquid chromatography in combination with inductively coupled plasma mass spectrometry. The mean seasonal concentrations of dominant soluble As specie—As(V)—ranged from 0.27 ng/m3 in the summer season in Warsaw to 2.41 ng/m3 in the winter season in Zabrze. Its mean mass shares in total As were 44% in Warsaw and 75% in Zabrze in the winter and 18% and 48%, respectively, in the summer. Obtained results indicated fossil fuel combustion as the main source of PM1-bound As(V) and road traffic emission as its minor sources. In opposite to As(V), soluble As(III) was not clearly seasonally variable. In both seasons, its mean concentrations were higher in Zabrze than in Warsaw. As(III) concentrations were not preferentially shaped by an exact emission from road traffic in both cities.

In vitro characterisation of ultrasound-induced heating effects in the mother and fetus: A clinical perspective

Ultrasound ◽  
2020 ◽  
pp. 1742271X2095319
Author(s):  
Stephanie F Smith ◽  
Piero Miloro ◽  
Richard Axell ◽  
Gail ter Haar ◽  
Christoph Lees
Keyword(s):  
Temperature Increase ◽  
Skin Surface ◽  
Maximum Temperature ◽  
Factors Affecting ◽  
Bone Interface ◽  
Heating Effects ◽  
Power Setting ◽  
Lower Temperature

Introduction The quantification of heating effects during exposure to ultrasound is usually based on laboratory experiments in water and is assessed using extrapolated parameters such as the thermal index. In our study, we have measured the temperature increase directly in a simulator of the maternal–fetal environment, the ‘ISUOG Phantom’, using clinically relevant ultrasound scanners, transducers and exposure conditions. Methods The study was carried out using an instrumented phantom designed to represent the pregnant maternal abdomen and which enabled temperature recordings at positions in tissue mimics which represented the skin surface, sub-surface, amniotic fluid and fetal bone interface. We tested four different transducers on a commercial diagnostic scanner. The effects of scan duration, presence of a circulating fluid, pre-set and power were recorded. Results The highest temperature increase was always at the transducer–skin interface, where temperature increases between 1.4°C and 9.5°C were observed; lower temperature rises, between 0.1°C and 1.0°C, were observed deeper in tissue and at the bone interface. Doppler modes generated the highest temperature increases. Most of the heating occurred in the first 3 minutes of exposure, with the presence of a circulating fluid having a limited effect. The power setting affected the maximum temperature increase proportionally, with peak temperature increasing from 4.3°C to 6.7°C when power was increased from 63% to 100%. Conclusions Although this phantom provides a crude mimic of the in vivo conditions, the overall results showed good repeatability and agreement with previously published experiments. All studies showed that the temperature rises observed fell within the recommendations of international regulatory bodies. However, it is important that the operator should be aware of factors affecting the temperature increase.

Optimization of Vortex Promoter Parameters to Enhance Heat Transfer Rate in Electronic Equipment

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Ece Aylı ◽  
Özgür Bayer
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Maximum Temperature ◽  
Transfer Coefficients ◽  
Enhance Heat Transfer ◽  
Distance Ratio ◽  
Heat Transfer Coefficients ◽  
Optimization Study ◽  
Finned Surface ◽  
Lower Temperature

Abstract In this paper, optimization of the location and the geometry of a vortex promoter located above in a finned surface in a channel with eight heat sources is investigated for a Reynolds number of 12,500 < Re < 27,700. Heat transfer rates and the corresponding Nusselt number distributions are studied both experimentally and numerically using different vortex promoter geometries (square, circular, and triangular) in different locations to illustrate the effect of vortex promoter on the fluid flow. Optimization study considered a range of following parameters: blockage ratio of 0.30 < (y/C) < 0.45 and interpromoter distance ratio of 0.2277 < (x/L) < 0.3416. Results show that fins over which rectangular and circular promoters are integrated perform better in enhancing the heat transfer. According to the numerical and experimental results, higher blockage ratios cause significantly higher heat transfer coefficients. According to the observations, as the interpromoter distances increase, shedding gains strength, and more turbulence is created. All vortex promoters enhance heat transfer resulting in lower temperature values on the finned surface for different (y/C) and (x/L) values and Reynolds numbers. The use of promoters enhances the heat transfer, and the decrease in the maximum temperature values is recorded on the finned surface changing between 15% and 27%. The biggest decrease in maximum surface temperature value is 500 K–364 K and observed in circular promoter case with (y/C) = 0.43, (x/L) = 0.3416, and Reynolds numbers of 22,200.

Numerical Solution of Heat Transfer for Single and Multi-Metal Pan

2011 ◽  
Vol 148-149 ◽  
pp. 227-231
Author(s):  
Behnam Nilforooshan Dardashti ◽  
Mohammad Reza Sedighi
Keyword(s):  
Heat Transfer ◽  
Hot Spots ◽  
Single Layer ◽  
Transient Behavior ◽  
Maximum Temperature ◽  
Composite Form ◽  
Grey Cast ◽  
Iron Iron ◽  
Copper Aluminum

The quantity and quality of heat transfer to food are important factors in cookware. They depend on temperature degree and Temperature Distribution (TD) on top surface of pan that is exposed to food. The heat is not uniformly spread over the pan so is appeared hot spots on the cooking surface. Using Multi-Layer Plate (MLP) causes regular TD on the top while bottom heated irregularly. Another significant properties in cookware is that how long it can stores heat and using non-reactive materials is another essentially consideration. In this study the main objective is to find the best structure (single or multi-layer) and the best metals to provide maximum temperature and uniform TD upside surface of pan and also analyzing transient behavior of used materials with goal of improving the thermal quality of pan to economize the energy. To achieve this aim were employed Finite Element Method (FEM). The analysis has been extended for Copper, Aluminum, Titanium, Stainless Steel in composite form and Grey cast iron, Iron, Carbon steel as single layer, we achieved the best TD on Cu/Ti MLP.

scholarly journals Hygroscopic properties of Amazonian biomass burning and European background HULIS and investigation of their effects on surface tension with two models linking H-TDMA to CCNC data

2010 ◽  
Vol 10 (12) ◽  
pp. 5625-5639 ◽  
Author(s):  
E. O. Fors ◽  
J. Rissler ◽  
A. Massling ◽  
B. Svenningsson ◽  
M. O. Andreae ◽  
...  
Keyword(s):  
Surface Tension ◽  
Biomass Burning ◽  
Organic Material ◽  
Inorganic Compounds ◽  
Pure Water ◽  
Condensation Nucleus ◽  
Water Soluble ◽  
Cloud Condensation Nucleus ◽  
Rural Site ◽  
Hygroscopic Properties

Abstract. HUmic-LIke Substances (HULIS) have been identified as major contributors to the organic carbon in atmospheric aerosol. The term "HULIS" is used to describe the organic material found in aerosol particles that resembles the humic organic material in rivers and sea water and in soils. In this study, two sets of filter samples from atmospheric aerosols were collected at different sites. One set of samples was collected at the K-puszta rural site in Hungary, about 80 km SE of Budapest, and a second was collected at a site in Rondônia, Amazonia, Brazil, during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC) biomass burning season experiment. HULIS were extracted from the samples and their hygroscopic properties were studied using a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) at relative humidity (RH) <100%, and a cloud condensation nucleus counter (CCNC) at RH >100%. The H-TDMA measurements were carried out at a dry diameter of 100 nm and for RH ranging from 30 to 98%. At 90% RH the HULIS samples showed diameter growth factors between 1.04 and 1.07, reaching values of 1.4 at 98% RH. The cloud nucleating properties of the two sets of aerosol samples were analysed using two types of thermal static cloud condensation nucleus counters. Two different parameterization models were applied to investigate the potential effect of HULIS surface activity, both yielding similar results. For the K-puszta winter HULIS sample, the surface tension at the point of activation was estimated to be lowered by between 34% (47.7 mN/m) and 31% (50.3 mN/m) for dry sizes between 50 and 120 nm in comparison to pure water. A moderate lowering was also observed for the entire water soluble aerosol sample, including both organic and inorganic compounds, where the surface tension was decreased by between 2% (71.2 mN/m) and 13% (63.3 mN/m).

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