Summertime Research Articles

Implementation of machine learning techniques for the quasi real-time blind and electric lighting optimization in a controlled experimental facility

Machine Learning techniques have been recently investigated as an alternative to the use of physical simulations, aiming to improve the response time of daylight and electric lighting performance-predictions. In this study, daylight and electric lighting predictor models are derived from daylighting RADIANCE simulations, aiming to provide visual comfort to office room occupants, with a reduced use of electric lighting. The aim is to integrate an intelligent control scheme, that, implemented on a small embedded 32-bit computer (Raspberry Pi), interfaces a KNX system for a quasi-real-time optimization of the building parameters. The present research constitutes a step towards the broader goal of achieving a unified approach, in which the daylight and electric lighting predictor models would be integrated in a Model Predictive Control. A verification of the ML performance is carried-out by comparing the model predictions to data obtained in monitoring sessions in autumn, winter and spring 2020-2021, resulting in an average MAPE of 19.3%.

Temporal and spatial changes of macrobenthos communities in south east shores of the Caspian sea

In this research, Sampling of macrobenthos of Mazandaran beaches was performed in 7 stations at two depths of 5 and 10 meters during four seasons in 2020 using a grab with 8 replications in each station. In this study, a total of 10472 individuals were counted, which belonging to 22 species from 13 families. The highest frequency of macrobenthos (648 ± 170.79) was observed in spring and the highest amount of biomass (36.21 ±2.5 gr / m2) was observed in winter. Moreover, the highest prevalence of macrobenthos predominant groups during the sampling period was observed in Bivalves (40%), Crustaceans (36%), Annelids (22%) and Gastropoda (2%), respectively. The results of PERMANOVA analysis showed that the effect of two factors of season and depth impacted the biomass, abundance, species richness, species composition and community structure of macrobenthos significantly. Furthermore, the results showed that with increasing the depth from 5 to 10 meters, macrobenthos abundance increased by 4, 2, 1 and 9 times in spring, summer, autumn and winter, respectively. Moreover, increase in depth from 5 to 10m, the values of biomass and species richness have increased. In according to these results, it can be concluded that biomass and diversity index of macrobenthos communities change considerably in different seasons and depths. Therefore, natural changes of these variables should be considered when using these macrobenthos communities to assess the impact of environmental factors.

A study of Indoor Environment of Large Glazed Office Building in Semi Arid Climate

In recent years the rate of buildings with large glazed facades is rapidly increasing, particularly in office buildings. Where, the creation of a suitable thermal and visual comfort is a significant factor affecting productivity. The use of large glazed facades without adapted shading measure generates thermal and visual discomfort, wich ranges from uncomfortable environment conditions to serious health effects. Specialized work and literature about performance evaluation of large glazed office buildings in relation to their environment are lacking in semi arid climates, characterized by significant intensity of solar radiations in the summer period of the year. This study investigates the impact of large glazing areas on thermal and visual comfort in a sample of naturally ventilated office building located in the semi arid climate of Algeria (36°, 17 N and 7°, 23’ E). A Post Occupancy Evaluation technique (POE), being a mainstream activity in the process of building operation phase is used for this purpose. The main objective is to stress practitioners, specifically architects, to take conscious decisions in an early phase of design process. The study clearly highlighted discomfort in the studied office building. It included unacceptable temperature arising from glazed facade; overheating due to excessive solar gains; insufficient ventilation and poor daylighting. The results indicate that such large fenestration system is not recommended in summer time. However, a judicious choice of the glazing size and type by simulation tools must balance lighting and thermal needs.

COVID-19 Australia: Epidemiology Report 52 Reporting period ending 10 October 2021.

This is the fifty-second epidemiological report for coronavirus disease 2019 (COVID-19), reported in Australia as at 23:59 Australian Eastern Daylight Time [AEDT] 10 October 2021. It includes data on COVID-19 cases diagnosed in Australia and the international situation.

What Are Sheep Doing? Tri-Axial Accelerometer Sensor Data Identify the Diel Activity Pattern of Ewe Lambs on Pasture.

Monitoring activity patterns of animals offers the opportunity to assess individual health and welfare in support of precision livestock farming. The purpose of this study was to use a triaxial accelerometer sensor to determine the diel activity of sheep on pasture. Six Perendale ewe lambs, each fitted with a neck collar mounting a triaxial accelerometer, were filmed during targeted periods of sheep activities: grazing, lying, walking, and standing. The corresponding acceleration data were fitted using a Random Forest algorithm to classify activity (=classifier). This classifier was then applied to accelerometer data from an additional 10 ewe lambs to determine their activity budgets. Each of these was fitted with a neck collar mounting an accelerometer as well as two additional accelerometers placed on a head halter and a body harness over the shoulders of the animal. These were monitored continuously for three days. A classification accuracy of 89.6% was achieved for the grazing, walking and resting activities (i.e., a new class combining lying and standing activity). Triaxial accelerometer data showed that sheep spent 64% (95% CI 55% to 74%) of daylight time grazing, with grazing at night reduced to 14% (95% CI 8% to 20%). Similar activity budgets were achieved from the halter mounted sensors, but not those on a body harness. These results are consistent with previous studies directly observing daily activity of pasture-based sheep and can be applied in a variety of contexts to investigate animal health and welfare metrics e.g., to better understand the impact that young sheep can suffer when carrying even modest burdens of parasitic nematodes.

Effect of the Seasonal Adaptability on Carbohydrate-electrolyte Beverage Efforts on Post-exercise Rehydration in Healthy Young Men

Objective To compare the effects of carbohydrate-electrolyte beverage on post-exercise rehydration of healthy young men in different seasons,and to explore the influence of seasonal adaptability on fluid and electrolyte balance.Methods Fifteen healthy men,aged(24.4±0.5)years,completed 2 trails in a random crossover design both in summer and winter.During recovery,they consumed a drink volume equivalent to 100% of their sweat loss with plain boiled water(the water group)or carbohydrate-electrolyte beverage(the beverage group).Recovery was monitored for further 180 minutes by the collection of blood and urine samples.Results The dehydration time in summer was significantly shorter by about 20 minutes than that in winter(t=3.045,P=0.004).In summer,the fluid retention rate of the beverage group was significantly higher than that of the water group at 120 minutes after rehydration [(83.7±2.8)% vs.(73.7±3.7)%,F=5.312,P=0.028],and significantly higher than the water group at 180 minutes [(74.8±3.6)% vs.(66.1±4.3)%,F=4.340,P=0.046].In winter,the fluid retention rate of the beverage group at 180 minutes after rehydration was significantly higher than that of the water group [(74.9±4.7)% vs.(68.0±6.0)%,F=4.128,P=0.048].There was no significantly seasonal difference in the fluid retention effect of carbohydrate-electrolyte beverage at 180 minutes after rehydration.In the beverage group,the changes of blood glucose and serum sodium levels(all P<0.05)in summer were significantly higher than those in winter at 10-180 minutes after rehydration,and the fractional excretion of sodium in summer was significantly higher in summer than in winter at 120 and 180 minutes after rehydration(F120=4.972,P=0.034;F180=8.425,P=0.007);however,there was no significant difference in plasma osmolality(all P> 0.05).For the water group,the plasma osmolality in winter was lower than that in summer,while the degree of dryness and thirst was higher in winter than in summer.Conclusions Seasonal adaptability influenced the hydration status and its regulating factors.People dehydrated faster after exercise in summer than in winter,and the hydration status was relatively stable in winter.However,in summer,the blood glucose and electrolytes responded more rapidly to carbohydrate-electrolyte beverage supply,and the plasma osmolality and subjective perception recovered faster.Therefore,during the 180-minute recovery period,the carbohydrate-electrolyte beverage had a higher rehydration efficiency in a short recovery time in summer although there was no significantly seasonal difference in the fluid retention rate.

Enhanced absorption house connection station for low district heating return line temperatures

Since the first publishing of district heat driven heat pumps at AGFW fair in 2014 in Frankfurt am Main, Germany, introducing a concept how to use additionally the district heat return line as low temperature heat source, the topic gains more and more international scientific and public interest. Hydraulic concepts with and without an additional heat exchanger in the district heat supply line are tested at least in China and Germany. In theory, a reduction of temperature in the district heating return line (DH-rl) can be expected in the range of 25 to 30 K in comparison to standardized DH house connection stations (HCS). However, when the same heat pump is used in cooling mode during summer time, DH-rl temperature reduction in heating mode is limited to a range of 15 to 20 K, due to absorption chiller hydraulics and system design.In the first part of this contribution experimental results are presented which show how the expected reduction of 25 to 30 K has been achieved in practice by an adapted heat pump design. In the second part a new hydraulic design and control concept for the district heat supply flow rate will be presented which enables even higher DH glides also for retrofitted heating systems. Operating a house heating system at 65/45 °C with a conventional HCS may lead to a temperature in DH-rl in the range of 48 – 55 °C. With the first concept of an absorption HCS from 2014 a DH return temperature of 30 – 35 °C is possible, whereas, with the new hydraulic concept the return temperature may decrease down to 20 – 30 °C for layout conditions. In comparison to conventional HCS the enhanced absorption HCS allows to save 15 – 40 % of volume flow rate for the same heating capacity, mainly depending on temperature level of district heat and house heating system. By means, the heat losses in DH networks can be reduced and the transport capacity (i.e. the number of potential households to be served) can by increased. Concept and calculated results for the enhanced absorption HCS are presented.

Administrative and legal enforcement of order calculation of time in Ukraine.

The article deals with a topical problem – a general description of the features of administrative-legal support of the calculation of time in Ukraine. In particular, the author emphasizes that the proper provision of public needs in the field of time calculation in Ukraine is entrusted to the executive authorities - the government and its relevant structures. Public administration relations arising from the above needs, based on the content of the subject of administrative law, belong to the scope of this branch of Ukrainian law. It has been noted that the history of the problem shows that during the stay of Ukrainian lands in other countries, the definition of time for Ukrainians, as well as for other European nations, was not stable and still has not become final. Time zone (UTC + 2) was introduced on the territory of the Ukrainian SSR as a component of the USSR on May 2, 1924, and maternity time was introduced on the territory of the Soviet Union on June 20, 1930, after which the time of the third zone (UTC + 3) on the territory of Soviet Ukraine became also year-round. The attention has been paid that from July 1, 1990 on the territory of the USSR the maternity time was abolished and the UTC + 2 time zone was restored, from September 29, 1991 summer time was also abolished. However, by the Resolution of March 6, 1992, the Verkhovna Rada of Ukraine restored the validity of this time. Thus, after the above-mentioned government decisions, Kyiv time became equal to the corresponding zone UTC+2, and during summer time - UTC+3. Another attempt to change the time took place last year, when at the initiative of R.O. Stefanchuk, the bill № 4201 of 09.10.2020 «On the calculation of time in Ukraine» was submitted to the parliament, which provided for the waiver of the seasonal transition of time from 2021. It has been emphasized that at least six factors, namely political, economic, international, physiological, socio-domestic and geographical, should be the basis of government decisions to change the time in the country (including in Ukraine). Peculiarities that characterize the current process of administrative and legal support for changing the procedure for calculating the time mine in our country are: its significant politicization, low level of preparedness, implementation in conditions of significant time lag, lack of proper communication between government and the people, the need for coordination and synchronization with EU, the implementation in the traditional format of legal (administrative-legal) regulation, in which, as a rule, is sufficiently simplified without due regard for the nature and characteristics of certain social relations is their legal regulation. The attention has been paid to the fact that there is a high probability that the 17 EU countries that currently live in the first time zone (GMT + 1) may permanently stay in summer time – GMT+2. According to the legislative initiative of R.O. Stefanchuk, at the same time GMT+2 as a year-round is proposed to be introduced in Ukraine. That is, 17 EU countries will remain in the summer, and we in the winter. As a result, Kyiv time will be equal to Warsaw, Berlin or Paris, which, given the significant actual difference in real time, can bring significant inconvenience to most Ukrainian citizens, and our country has major, including security problems. The author has stated that the administrative-legal support of the calculation of time in Ukraine is characterized by a number of features, the main of which is its actual absence. Instead of providing groups with relevant social needs, our state continues to use an outdated and ineffective format of legal regulation of social relations. This leads to one-sidedness, simplification and haste in the preparation of relevant regulations. Under the conditions of immediate introduction of a more effective scheme of providing administrative legal needs, the issues of time calculation in Ukraine will most likely be solved systematically, comprehensively with proper scientific substantiation, taking into account all specific social needs and significant features that characterize this important component of public life.

Effects of Photoperiod, Water temperature, and Exogenous Hormones on Spawning and Plasma gonadal Steroid in Starry Flounder, Platichthys stellatus

The sexual maturation and spawning of teleosts are regulated by the external environment and the endocrine system. When the environmental conditions are artificially adjusted at a fish farm, the maturity and spawning of fish can be controlled. In this study, sexual maturation and spawning of the starry flounder, Platichthys stellatus, were artificially induced by adjusting the water temperature and photoperiod at a fish farm to accelerate the species’ natural spawning period. One experimental group acted as a control and was exposed to a natural photoperiod and natural water temperature (NPNT). In contrast, another experimental group was exposed to an adjusted environment consisting of a regulated photoperiod and temperature (RPRT). Daylight time was reduced by 10 minutes every 3 days from 13 hours to a duration of 8 hours. The water temperature was first reduced by 1oC every day, starting at 22oC and ending at 8oC, and then raised to 10oC until the spawning period. Both experimental groups were treated with gonadotropin-releasing hormone analog (GnRHa) pellets to induce ovulation. The results show that when the water temperature and photoperiod were artificially controlled, ovulation could be induced 97 days earlier than the natural spawning. Plasma testosterone levels of RPRT and NPNT tended to increase and then decrease 1–2 months before spawning, and plasma levels of 17α,20β-dihydroxy-4-pregnen-3-one increased 1–2 months before spawning. The concentration of estradiol-17β (E2) in plasma was not associated with spawning.

Significance of the organic aerosol driven climate feedback in the boreal area

Aerosol particles cool the climate by scattering solar radiation and by acting as cloud condensation nuclei. Higher temperatures resulting from increased greenhouse gas levels have been suggested to lead to increased biogenic secondary organic aerosol and cloud condensation nuclei concentrations creating a negative climate feedback mechanism. Here, we present direct observations on this feedback mechanism utilizing collocated long term aerosol chemical composition measurements and remote sensing observations on aerosol and cloud properties. Summer time organic aerosol loadings showed a clear increase with temperature, with simultaneous increase in cloud condensation nuclei concentration in a boreal forest environment. Remote sensing observations revealed a change in cloud properties with an increase in cloud reflectivity in concert with increasing organic aerosol loadings in the area. The results provide direct observational evidence on the significance of this negative climate feedback mechanism.

Identifying the optimal travel path based on shading effect at pedestrian level in cool and hot climates

As shading affects thermal environments and intentions of outdoor activities, studying shaded areas is necessary to increase pedestrian travel choice. This study provided a new insight by calculating the shading length based on LiDAR data and then identifying the optimal pathway for demonstrating the shading effects at different times in summer and winter. The Kowloon Peninsula of Hong Kong was selected as the study area. Results revealed that streets oriented N-S and NE-SW before and at noon and N-S and E-W after noon are beneficial for strong shading effects in summer, and streets oriented NE-SW and NW-SE during 8:00–10:00 and 14:00–16:00 and streets oriented N-S and NW-SE at 12:00 are suitable for travel with intense solar radiation in winter. The area percentages of overlapping areas of pathways oriented E-W and N-S at different times in summer and winter demonstrated what times pedestrians can choose to go through the overlapping pathways (e.g. pathways oriented E-W during 8:00–10:00 and during 14:00–16:00) or stay in the overlapping open spaces. The more overlapping pathways based on the random points were found at different times in winter than summer. The study reflects when and in which public spaces individuals can walk or perform outdoor activities.

UJI BEBERAPA KONSENTRASI EKSTRAK UMBI GADUNG (Dioscorea hispida Dennst) TERHADAP HAMA KEONG MAS (Pomacea canaliculata L.)

Riau is one of a lowland rice producing provinces. One of the pests that can reduce rice productivity is the golden snail (Pomacea canaliculata L.). The solution for controlling the golden snail (P. canaliculata L.). Pest uses environmentally friendly control techniques, namely botanical pesticides of gadung tubers. This study aims to obtain a concentration of the extract of gadung tuber flour (Dioscorea hispida Dennst) which is effective in controlled the attack of golden snails (P. canaliculata L.) in lowland rice plants. This research was conducted experimentally using completely randomized design (CRD) consisting of five treatments and four replications, in order to obtain 20 experimental units. The treatments consisted of concentrations of gadung tubers extract, namely 0 g.l-1, 25 g.l-1, 50 g.l-1, 75 g.l-1, and 100 g.l-1. Observations included the initial dst time to snail death, lethal time 50 (LT 50), daily total mortality, and behavior changes in behavior. The results showed that the application of 100 g.l concentration of gadung tuber extract treatment caused the highest total mortality of golden snails (P. canaliculata L.) of 74.99%, but it was not effective yet in controlling the golden snail pest because it was not able to kill the golden snail above 80%.

Sunlight Exposure: A Protective Role in the Development of Myopia

The study objective was to assess the correlation of time outdoors in sunlight hours with spherical equivalent refraction (SER) and other variables. This was a cross-sectional study carried out in the Fauji Foundation Hospital, Rawalpindi, between January and April 2019. A total of 110 Individuals were included via convenient sampling, with myopia defined as having at least -0.5 D (SER ≤ -0.5 D). Collection of Questionnaires with interviews regarding eye care behaviour along with auto-refraction was done, followed by calculation of spherical equivalent refraction. Those having high myopia of 6 D or more (SER ≤ - 6 D), hyperopia of 0.5 D or more (SER ≥ +0.5 D), and history significant for ocular trauma and surgeries, were excluded. After data cleaning and their entry, analyses were done using SPSS version 26. The mean age data, available for 105 individuals, was 15.4 ± 3.69 years. Spearman's correlation was used for right SER with time outdoors in summers (r= +0.25, p=0.008) and winters (r= +0.243, p=0.010), indicating an inverse relationship with myopia. Females had more myopic refraction than males, but the independent sample t-test was not significant. Logistic regression was used and a protective effect was found for both summer and winter time outdoors, while education level was associated with myopia. Key Words: Myopia, Spherical equivalent refraction (SER), Sunlight exposure.

Effect of tree species and season on the ability of forest floors to abate environmental noise

The nature of the ground beneath a belt of trees along transport infrastructure can contribute significantly to the associated noise abatement. To get more insight in this topic, repeated measurements were performed, both in winter and summer time, in a common garden of six monoculture broadleaved tree stands (ash, cherry, lime, maple, beech and oak, all of the same age). A two-microphone technique was used to derive the ground surface impedance and soil properties describing the interaction between the forest floor and sound waves. The slit-pore and Zwikker and Kosten (phenomenological) ground impedance model, both in rigid backing configuration, were found to adequately predict the measured short-range level differences. The much higher moisture content of the forest floor during the winter campaign resulted in a strong increase in the deduced surface impedance. A clear overall tree species effect seemed absent, despite large differences in litter degradation rates. Additional measurements after raking away the organic layer allowed concluding that a pronounced forest floor might compensate for an acoustically harder mineral soil beneath. In tree belts aiming at noise reduction, litter should not be removed and care is needed not to compact the mineral soil, especially in case of stands with rapidly decaying litter and a thin organic horizon.

The Lower Vistula and Its Ice Problems

Abstract In many countries of the northern hemisphere during winter period ice forms appear on various water bodies, which results in significant changes of physical, chemical and ecological conditions. These changes are different in rivers, channels, lakes or once-through reservoirs. On the terrain of Poland ice always caused considerable problems affecting intensive inland navigation and other river use. These problems appeared especially on the Vistula River, which in 17th and 18th century was one of the most navigable rivers in Europe. The Vistula is the largest Polish river, which flows from the south in the Carpathian Mountains to the Baltic Sea in the north. It is the second largest river, after Neva, of the Baltic Sea catchment. The length of the Vistula is 1047 km and its catchment amounts to 194 thousand km2. The predominant part of the Vistula river basin (87%) is now on Polish territory and the remaining (13%) catchment is in Belarus, Ukraine and Slovakia. The course of the Vistula can be divided into three distinctly different sections: upper, middle and lower. These river sections have appropriate catchments with their tributaries. There are hydraulic structures on the main river course and on its tributaries which serve navigation, hydroenergy, flood protection, water supply and recreation. All over the Vistula catchment there are frequent floods during spring and summer time resulting from excessive precipitation but in winter caused by ice phenomena. Numerous flow problems appear especially along the lower Vistula course because of ice phenomena and they result very often in severe flood problems. The Vistula has a very variable time and spatial discharge, because of existing climate conditions over its catchment. The aim of the paper is to present hydraulic and hydrologic characteristics of the Lower Vistula river with special emphasis on the management of this river section for navigation, hydroenergy, flood protection and water supply in view of ice phenomena appearing there. Information concerning changes of water characteristics due to various water temperatures are presented as well as on the formation of various forms of ice in flowing water. Numerous ice studies were carried out in Poland and especially on the Lower Vistula section as it was very ice prone and where many ice jams and ice-jam floods occurred. A special hydraulic situation existed at the mouth of the Vistula, which caused important floods in the 18th century and resulted in the construction of a special direct channel to the sea (Przekop Wisły) solving flood problems in this area. Information is presented on changes in open channel flow due to the appearance of ice cover and other ice forms. The paper includes ample information on the run, consequences and studies connected with a very important ice-jam-flood on the upper part of Włocławek reservoir in 1982.

A numerical study of the urban green roof and cool roof strategies’ effects on boundary layer meteorology and ozone air quality in a megacity

Green roof and cool roof are two popular strategies to mitigate urban heat island especially in the summer time. The meteorological effect (cooling on the near surface temperature) of the two mitigation strategies has been proved by lots of studies while the environmental effect (effect on urban air quality) is still largely unknown. In this paper the WRF-Chem model coupled with a single layer urban canopy model is used to simulate three heat wave and heavy ozone pollution episodes in Shanghai, China. Sensitivity experiments of green roof and cool roof are carried out and the results show that both green roof and cool roof can effectively mitigate urban heat island, and their cooling efficiencies are similar even their cooling mechanisms are different. All of them can reduce the lasting time and area of high temperature and extreme hot, but the ozone pollution may become more serious. According to the different ambient wind field and ozone distribution, these three ozone pollution episodes can be divided into two conditions: urban dome and urban plume. The decrease of urban surface temperature can inhibit the turbulent activities and reduce the height of the boundary layer; the concentration of ozone in urban Zone A (below 750 m height) increases, but decreases in urban Zone B (750 m-2km height) for urban dome. By calculating the ozone fluxes at different heights, we find that the urban heat island circulation can transport surface ozone into city, horizontally; while in Zone B, the horizontal divergence transport ozone out of the city, and green roof and cool roof can decrease the temperature difference between urban and suburban, which can inhibit this ozone transportation of urban heat island circulation.

What can we learn from the online learning experiences of medical students in Poland during the SARS-CoV-2 pandemic?

BackgroundIn March 2020, due to the SARS-CoV-2 pandemic, the Polish government ordered the closing of all medical faculties, with an obligatory shift to online learning. This lockdown continued, with a short period of blended learning, over the time of summer 2020. Distance learning had previously been rarely used within Polish medical schools, so such a sudden transfer was a major challenge. The aim of the study was to explore undergraduates’ perception of online teaching provided at Polish medical faculties during the pandemic and to analyze how these experiences may inform future curriculum development.MethodsThe online survey was addressed to undergraduates at Polish medical faculties in November 2020. The questions captured demographics, epidemiological data and students’ perception of various aspects of online teaching. Responses were subjected to thematic analysis and their distribution compared considering demographic parameters .ResultsSix hundred twenty students from thirteen medical faculties responded to the survey. Major benefits from online teaching perceived by respondents included increased convenience, enhanced quality, a sense of comfort and safety. Major complaints were associated with unsatisfactory content, technical issues, difficulties engaging, poor organization and lack of social life. Students claimed that online teaching required more self-directed learning and discipline and 57.9% considered this impact as negative. 44.5% of respondents took part in educational online activities beyond their scheduled classes. For 49.2% online examinations were reported as more stressful and for 24.8% - less stressful than traditional ones. Differences in the opinions on online teaching were found between men and women, students in early and senior years, Polish and non-Polish ones.ConclusionsThe sudden move online inevitably was problematic for students. Their perspective afforded us the opportunity to consider shortcomings of pre-pandemic undergraduate curriculum. Online education requires a more self-directed learning, which was challenging for many students, so further enhancement of more autonomous study skills seems necessary. Distress expressed by students indicates the need for urgent support with mental health issues.

Detection of acoustic wave generated by Baganuur mining explosion

We analyzed all available recorded infrasound data and determined the station detection capability in Mongolia. While in the winter times, we continuously detect acoustic signals from blasts at the Baganuur open-pit mine (150 km from infrasound I34MN station), which we rarely registered during the summer times. A previous study has shown that the noise level increased by 5 dB - 10 dB in the summer, which affected the detection capability of the stations. On the other hand, this could be connected to infrasound propagation model difference between winter and summer times. To verify this phenomenon, we installed a new infrasound IBHM station in a forest area at a distance of 350 km from the Baganuur mine area. When we compared the background noise level of the two stations, the noise level at the temporary station was lower than the permanent one, which allowed us to compare winter and summer time registered infra wave characteristics. With the comparison observed and modeled, apparent velocity suggested that winter and summer time detection difference could be due to the propagation model of infrasound wave itself.

Measuring and modeling moisture environment in underground metro stations during commissioning stage: A case study

Due to the humid underground environment, underground metro stations often have internal condensation issues, especially during the commissioning and initial operation phases, and these issues will have a negative impact on the equipment operation and building life. This study aims to solve the issue by 1) identifying common areas with condensation risks based on on-site measurements and numerical simulation methods, and 2) proposing effective dehumidification solutions for the moisture control of stations. By on-site investigating the characteristics of the station’s moisture environment and numerical assessing the effects of two different dehumidification strategies, it has been found that 1) for Tianjin, during most times in summer, the air temperature of the station in the commissioning phase was maintained relatively stable, but with significantly changing humidity; 2) the relative humidity on the platforms was higher than 80% for almost 30% of the testing time, and the surface of the upper structure of platform doors having a high risk of condensation; 3) the dehumidification effect of industrial dehumidifiers was found to be better than that of increasing exhaust air volume. The authors hope that the research could aid the decision on dehumidification strategies and provide guidance for further moisture control in underground stations. Practical Application This article analyzed the moisture environment of the underground metro stations in the commissioning phase and conducted a numerical approach to assess the condensation risk. Potential dehumidification solutions including increasing the exhaust air volume and using industrial dehumidifiers have been proposed, and their effects have been investigated and compared. The authors hope that this research can aid the decision on dehumidification strategies for facilities maintenance and provide a guidance to further moisture control in underground stations.

Long-term seasonal and temporal changes of hydrogen peroxide from cyanobacterial blooms in fresh waters

In water, hydrogen peroxide (H2O2) is produced through abiotic and biotic reactions with organic matter, including algal cells. The production of H2O2 is influenced by harmful algal cell communities and toxicity. However, only a few studies have been conducted on H2O2 concentrations in natural water. Particularly, the seasonal and temporal patterns of H2O2 concentration suggest that H2O2 generation from aquatic microorganisms could be identified to compare of photochemical production from dissolved organic matter. Study area is a source of raw water and is a large artificial lake located near a metropolitan city. Due to various environmental conditions, harmful algal blooms frequently occur in summer. The purpose of this study was to trace the H2O2 concentration and water quality parameters of study area where algal bloom occurs and what factors directly affect the H2O2 concentration. Experiments were performed on the influencing factors via water samples from study area and lab-scale culture tank. The lake produces an average of 553 nM H2O2, which increases by more than three times (1460 nM) in summer compared the winter. The lake (18.6–23.8 nMh−1) produced more H2O2 than streams (7.4–9.0 nMh−1) during daylight hours. All water sites presented the lowest production rates in dark conditions (1.1–1.5 nMh−1). Daytime environment increased the generation rate more than the nighttime. The trend of H2O2 produced by algal cells was similar to that of the growth of algal cells. The exposure to external substances (heavy metals and antibiotics) increased the incidence by approximately five times; antibiotics were more influential than heavy metals.