Predicting of atmospheric corrosivity and durability of structural materials. Part II. Impact of urban traffic pollution

2021 ◽  
Vol 26 (2) ◽  
pp. 25-33
Author(s):  
Joanna Kobus ◽  
Rafał Lutze

The results of the atmospheric corrosivity assessment in the immediate vicinity of streets of different traffic volume in Warsaw, Krakow and Katowice are derived . On the bases of annual exposures in 2014–2018 years an equation describing the impact of environmental parameters and street traffic volume on corrosion losses of zinc and zinc coating on steel was selected.

2018 ◽  
Vol 231 ◽  
pp. 01012
Author(s):  
Joanna Kobus ◽  
Lech Kwiatkowski ◽  
Rafał Lutze

The work is aimed at determining the corrosivity of atmosphere in the vicinity of roads, taking into account the characteristics of local emission sources, including traffic intensity of vehicles along with climatic and exploitation factors. Determination of the corrosivity of atmosphere was carried out according to the procedures described in PN EN ISO standards. Samples for testing were made of low carbon steel DC05, zinc and hot dip galvanized steel. Samples were assembled at 19 sites in the close vicinity of roads and highways near the measurement points of vehicle traffic intensity. The mass loss of exposed samples was the basis for determination the atmosphere corrosivity at each of 19 test sites. Regarding steel, the corrosivity category of C4 was observed at 8/19 sites. Corrosion losses outside roads are 2-4 times lower and ranged within the categories of C2 and C3. Zinc corrosion losses classified to category C4 occurred at 2/19 stations. In the remaining ones they corresponded to category C3. In areas outside of roads, zinc corrosion losses are about 20-100% lower (C2). The first attempts to model the dependence of operating and environmental parameters on zinc and zinc coating corrosion losses indicate significant correlation between zinc and zinc coating corrosion losses as a function.


2021 ◽  
pp. 1-16
Author(s):  
Lixin Yan ◽  
Tao Zeng ◽  
Yubing Xiong ◽  
Zhenyun Li ◽  
Qingmei Liu

With the development of urbanization, urban traffic has exposed many problems. To study the subway’s influence on urban traffic, this paper collects data on traffic indicators in Nanchang from 2008 to 2018. The research is carried out from three aspects: traffic accessibility, green traffic, and traffic security. First, Grey Relational Analysis is used to select 18 traffic indicators correlated with the subway from 22 traffic indicators. Second, the data is discretized and learned based on Bayesian Networks to construct the structural network of the subway’s influence. Third, to verify the reliability of using GRA and the effectiveness of Bayesian Networks (GRA-BNs), Bayesian Networks with full indicators analysis and other four algorithms (Naive Bayes, Random Decision Forest, Logistic and regression) are employed for comparison. Moreover, the receiver operating characteristic (ROC) area, true positive (TP) rate, false positive (FP) rate, precision, recall, F-measure, and accuracy are utilized for comparing each situation. The result shows that GRA-BNs is the most effective model to study the impact of the subway’s operation on urban traffic. Then, the dependence relations between the subway and each index are analyzed by the conditional probability tables (CPTs). Finally, according to the analysis, some suggestions are put forward.


2021 ◽  
Vol 13 (12) ◽  
pp. 2329
Author(s):  
Elżbieta Macioszek ◽  
Agata Kurek

Continuous, automatic measurements of road traffic volume allow the obtaining of information on daily, weekly or seasonal fluctuations in road traffic volume. They are the basis for calculating the annual average daily traffic volume, obtaining information about the relevant traffic volume, or calculating indicators for converting traffic volume from short-term measurements to average daily traffic volume. The covid-19 pandemic has contributed to extensive social and economic anomalies worldwide. In addition to the health consequences, the impact on travel behavior on the transport network was also sudden, extensive, and unpredictable. Changes in the transport behavior resulted in different values of traffic volume on the road and street network than before. The article presents road traffic volume analysis in the city before and during the restrictions related to covid-19. Selected traffic characteristics were compared for 2019 and 2020. This analysis made it possible to characterize the daily, weekly and annual variability of traffic volume in 2019 and 2020. Moreover, the article attempts to estimate daily traffic patterns at particular stages of the pandemic. These types of patterns were also constructed for the weeks in 2019 corresponding to these stages of the pandemic. Daily traffic volume distributions in 2020 were compared with the corresponding ones in 2019. The obtained results may be useful in terms of planning operational and strategic activities in the field of traffic management in the city and management in subsequent stages of a pandemic or subsequent pandemics.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong Kwan Lim ◽  
Oh Joo Kweon ◽  
Hye Ryoun Kim ◽  
Tae-Hyoung Kim ◽  
Mi-Kyung Lee

AbstractCorona virus disease 2019 (COVID-19) has been declared a global pandemic and is a major public health concern worldwide. In this study, we aimed to determine the role of environmental factors, such as climate and air pollutants, in the transmission of COVID-19 in the Republic of Korea. We collected epidemiological and environmental data from two regions of the Republic of Korea, namely Seoul metropolitan region (SMR) and Daegu-Gyeongbuk region (DGR) from February 2020 to July 2020. The data was then analyzed to identify correlations between each environmental factor with confirmed daily COVID-19 cases. Among the various environmental parameters, the duration of sunshine and ozone level were found to positively correlate with COVID-19 cases in both regions. However, the association of temperature variables with COVID-19 transmission revealed contradictory results when comparing the data from SMR and DGR. Moreover, statistical bias may have arisen due to an extensive epidemiological investigation and altered socio-behaviors that occurred in response to a COVID-19 outbreak. Nevertheless, our results suggest that various environmental factors may play a role in COVID-19 transmission.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1217
Author(s):  
Shun Li ◽  
Caimin Huang ◽  
Jin Chen ◽  
Yu Tang ◽  
Shuxin Bai

Energetic structural materials (ESMs) are an important class of military materials due to their good structural and energy-releasing characteristics. To improve the damage effect of metal–metal ESMs with good mechanical properties, W was added to the 48Al–52Ni composites, and the effect of W on the impact-induced energy release behaviors was investigated. The results showed that the hot-press process and the addition of W did not change the microstructure and surface state of the constituent particles, leading to a stable onset temperature of the Al–Ni intermetallic reaction in (48Al–52Ni)100-xWx composites. Meanwhile, the decrease in the contact area between Al and Ni in the composites with increased W content resulted in the decrease in reaction heat. During the impact process, the intermetallic reaction of W caused by the Al–Ni intermetallic reaction, as well as the oxidation reaction of Al and Ni caused by the brittle fracture along the weak interface, caused the released energy of (48Al–52Ni)40W60 to reach 2.04 kJ/g.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 660
Author(s):  
Dariusz Jędrzejczyk ◽  
Elżbieta Szatkowska

The analyzed topic refers to the wear resistance and friction coefficient changes resulting from heat treatment (HT) of a hot-dip zinc coating deposited on steel. The aim of research was to evaluate the coating behavior during dry friction after HT as a result of microstructure changes and increase the coating hardness. The HT parameters should be determined by taking into consideration, on the one hand, coating wear resistance and, on the other hand, its anticorrosion properties. A hot-dip zinc coating was deposited in industrial conditions (according EN ISO 10684) on disc-shaped samples and the chosen bolts. The achieved results were assessed on the basis of tribological tests (T11 pin-on-disc tester, Schatz®Analyse device, Sindelfingen, Germany), microscopic observations (with the use of optical and scanning microscopy), EDS (point and linear) analysis, and microhardness measurements. It is proved that properly applied HT of a hot-dip zinc coating results in changes in the coating’s microstructure, hardness, friction coefficient, and wear resistance.


Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 180
Author(s):  
Negash Kabtimer Bereded ◽  
Getachew Beneberu Abebe ◽  
Solomon Workneh Fanta ◽  
Manuel Curto ◽  
Herwig Waidbacher ◽  
...  

The gut microbiota of fishes is known to play an essential role in diverse aspects of host biology. The gut microbiota of fish is affected by various environmental parameters, including temperature changes, salinity and diet. Studies of effect of environment on gut microbiota enables to have a further understanding of what comprises a healthy microbiota under different environmental conditions. However, there is insufficient understanding regarding the effects of sampling season and catching site (wild and aquaculture) on the gut microbiota of Nile tilapia. This study characterised gut microbial composition and diversity from samples collected from Lake Tana and the Bahir Dar aquaculture facility centre using 16S rDNA Illumina MiSeq platform sequencing. Firmicutes and Fusobacteria were the most dominant phyla in the Lake Tana samples, while Proteobacteria was the most dominant in the aquaculture samples. The results of differential abundance testing clearly indicated significant differences for Firmicutes, Fusobacteria, Bacteroidetes and Cyanobacteria across sampling months. However, Proteobacteria, Chloroflexi, Fusobacteria and Cyanobacteria were significantly enriched in the comparison of samples from the Lake Tana and aquaculture centre. Significant differences were observed in microbial diversity across sampling months and between wild and captive Nile tilapia. The alpha diversity clearly showed that samples from the aquaculture centre (captive) had a higher diversity than the wild Nile tilapia samples from Lake Tana. The core gut microbiota of all samples of Nile tilapia used in our study comprised Firmicutes, Proteobacteria and Fusobacteria. This study clearly showed the impact of sampling season and catching site (wild and aquaculture) on the diversity and composition of bacterial communities associated with the gut of Nile tilapia. Overall, this is the first study on the effects of sampling season and catching site on the gut microbiota of Nile tilapia in Ethiopia. Future work is recommended to precisely explain the causes of these changes using large representative samples of Nile tilapia from different lakes and aquaculture farms.


2021 ◽  
Vol 13 (6) ◽  
pp. 3585
Author(s):  
Dariusz Masłowski ◽  
Małgorzata Dendera-Gruszka ◽  
Ewa Kulińska

In the current era of urban development, people are already using electric vehicles more and more often for transport purposes, which reduces negative impacts on the environment. However, there are still vehicles in towns and cities that run on ordinary internal combustion engines. Performing optimization measures on the operation of these vehicles improves their performance, which can result in positive sustainable development effects. This article presents measures to reduce the wear and tear of urban vehicles and outlines a decision model to determine which of the vehicle parts described suffer the most frequent wear and tear under urban conditions. The article presents a list of structural elements that are most affected by urban traffic, as well as corrective actions to improve such specialized vehicles. Based on the decision analysis, Rule 1 was eliminated as having the least significant impact on vehicle wear and tear, and the least significant impact on urban safety. On the other hand, the most worn-out elements were found to be gearboxes, clutches, bus levelling electronics, and brake pads and discs. The decision-making model made it possible to identify the factors which have the greatest impact on reducing safety in urban spaces.


Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 74
Author(s):  
Dong-Chang Li ◽  
Chia-Chun Chen ◽  
Shien-Kuei Liaw ◽  
Shofuro Afifah ◽  
Jiun-Yu Sung ◽  
...  

Underwater wireless optical communication (UWOC) has been considered a promising technology for high-speed underwater transmission. Some Gb/s level UWOC systems applying visible light have been demonstrated with a transmission distance of several meters or more. Many of the previous works focus on the advanced technologies to push the systems’ capacity–distance performance. However, practical environmental factors issue such as flow turbulence and temperature variation are seldom studied through specific statistical/theoretical models. In this paper, a UWOC system using a 450 nm blue light laser source was set up using a 1.5-m water tank with mirrors located on both sides for single or multiple reflections corresponding to different transmission distances. The blue laser was modulated by a 1.25 Gbps NRZ-OOK format with PRBS of 7, 24 or 31, respectively, for system performance comparison. The bit error rate (BER) values were measured in 1.5, 3.0 and 6 m, respectively, for system evaluation. At room temperature, the BER value was down to 10 × 10−8 for a 1.25 Gbps data rate in a 6 m transmission. Then, the UWOC transmission system experiment was carried out under several environmental parameters such as temperature, turbulence, artificial seawater by adding salt to simulate practical application in river or sea. When a submerged motor with an output of 1200 L/h was used as a water flow turbulence source, the impact to BER and transmission quality was negligible. For the temperature change issue, the experiment shows that around the original temperature of 25 °C had the best BER as compared to other temperature ranges from 10 to 50 °C. For artificial seawater issues by adding salt to simulate the real seawater environment. The transmission distance was only 3-m instead of 6 m, mainly due to particle scattering and water disturbance. With the motor pump on, the power penalty was 1 dB at 10 × 10−8 BER when compared to the motor pump off.


2016 ◽  
Vol 2 (2) ◽  
pp. 223-246
Author(s):  
Tobias Brinkmann

This article examines the impact of transit migration from the Russian and Austro-Hungarian Empires on Berlin and Hamburg between 1880 and 1914. Both cities experienced massive growth during the last three decades of the nineteenth century, and both served as major points of passage for Eastern Europeans travelling to (and returning from) the United States. The rising migration from Eastern Europe through Central and Western European cities after 1880 coincided with the need to find adequate solutions to accommodate a rapidly growing number of commuters. The article demonstrates that the isolation of transmigrants in Berlin, Hamburg (and New York) during the 1890s was only partly related to containing contagious disease and ‘undesirable’ migrants. Isolating transmigrants was also a pragmatic response to the increasing pressure on the urban traffic infrastructure.


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