Unfavorable Atmospheric Conditions Research Articles

Investigation of a new solar-wind energy-based heat pump dryer for food waste drying based on different weather conditions

To date, many studies endeavors have been undertaken regarding the provision of energy necessary for heat pump drying systems utilizing renewable energy resources. Conversely, the contemporary heat pump dryers require both electricity and heat concurrently, whilst the sporadic availability of a particular renewable energy source throughout the day necessitates the utilization of a combination of multiple renewable sources as a prospective remedy to these predicaments. The present research aims to assess the practicability of integrating photovoltaic and thermal collectors with wind turbines for the purpose of meeting the energy demands of a food waste drying system. A study was conducted to evaluate the performance of a dryer with a fixed weight of 100 kg and a moisture removal rate of 71.42 kg/h under varying climatic conditions in the cities of St. Petersburg, Yekaterinburg, Yakutsk and Khabarovsk, Russia. The investigation took into account four key factors, specifically energy, exergy, economy, and environment, over a period of one year. The thermodynamic outcomes derived from economic considerations indicate that an increase in dryer usage leads to a decrease in energy efficiency and a rise in energy expenditure. According to the empirical data, the optimum utilization of the dryer was recorded in Khabarovsk urban center as a consequence of the favorable climatic milieu which facilitated an efficacious moisture extraction rate of 51850.92 kg/year. Conversely, the city of Yakutsk demonstrated the lowest utilization frequency of the dryer, attributable to the unfavorable atmospheric conditions which hindered an effective moisture extraction rate, recording a minimal usage frequency of 27996.64 kg/year. The production of clean electricity and avoidance of natural gas for heating purposes in the cities of Khabarovsk and Yakutsk resulted in the attainment of the most pronounced decreases in carbon dioxide emissions, as indicated by the recorded figures of 47.53 tons and 25.32 tons, respectively. Consequently, following an economic evaluation pertaining to optimal repayment time, based on an interest rate of 0.03 %, the cities of St. Petersburg, Yekaterinburg, Yakutsk and Khabarovsk demonstrate repayment periods of 12.9, 12.6, 18, and 9.6 years, respectively.

A scalable software package for time series reconstruction of remote sensing datasets on the Google Earth Engine platform

ABSTRACT Spatiotemporal residual noise in terrestrial earth observation products, often caused by unfavorable atmospheric conditions, impedes their broad applications. Most users prefer to use gap-filled remote sensing products with time series reconstruction (TSR) algorithms. Applying currently available implementations of TSR to large-volume datasets is time-consuming and challenging for non-professional users with limited computation or storage resources. This study introduces a new open-source software package entitled ‘HANTS-GEE’ that implements a well-known and robust TSR algorithm, i.e. Harmonic ANalysis of Time Series (HANTS), on the Google Earth Engine (GEE) platform for scalable reconstruction of terrestrial earth observation data. Reconstruction tasks can be conducted on user-defined spatiotemporal extents when raw datasets are available on GEE. According to site-based and regional-based case evaluation, the new tool can effectively eliminate cloud contamination in the time series of earth observation data. Compared with traditional PC-based HANTS implementation, the HANTS-GEE provides quite consistent reconstruction results for most terrestrial vegetated sites. The HANTS-GEE can provide scalable reconstruction services with accelerated processing speed and reduced internet data transmission volume, promoting algorithm usage by much broader user communities. To our knowledge, the software package is the first tool to support full-stack TSR processing for popular open-access satellite sensors on cloud platforms.

Causes of the Extreme Drought in Late Summer–Autumn 2019 in Eastern China and Its Future Risk

Abstract Eastern China (EC) suffered an extreme drought with long-lasting duration and record-breaking intensity in late summer–autumn 2019. Our diagnosed results show that the central Pacific (CP) El Niño, in tandem with warm sea surface temperature anomalies (SSTAs) over the Kuroshio Extension (KE) region, induces the meridionally elongated cyclonic circulation anomalies stretching from the western North Pacific (WNP) to the Yellow Sea. Its western flank corresponds to overwhelming low-level northerly wind anomalies over EC, which result in deficient moisture and anomalous descent over EC and hence cause the extreme drought in 2019. To investigate the relative contributions of SSTAs over different regions, we performed sensitivity experiments, and analyzed the relationship between extreme drought like what occurred in 2019 (a 2019Drought-like event) and the SSTAs in CMIP6 historical simulations. Modeling evidences reveal that both warm SSTAs over the central equatorial Pacific and the KE region are indispensable for shaping the meridionally elongated cyclone anomaly. Specifically, the cyclone anomaly over the WNP induced by CP El Niño aligns with the cyclone anomaly over the Yellow Sea induced by the warm SSTAs over the KE region, merging into a meridionally stretched cyclone anomaly to the east of EC. Consequently, the northerly anomalies stretch across EC, leading to unfavorable atmospheric conditions and the rainfall deficit there. Projection results show that the occurrence probability of a 2019Drought-like event will increase by 20% (decrease by 40%–50%) under a high (medium-low) emission scenario compared to present-day climate, indicating the nonlinear response of extreme drought to different emission scenarios and the urgency of carbon emission reduction. Significance Statement An extreme drought hit the Eastern China (EC) region in 2019 and caused tremendous losses. This study proposed that both the 2019 CP El Niño and the warm SST anomalies over the Kuroshio Extension (KE) region induce the meridionally elongated circulation anomalies and the resultant extreme drought. We showed that the typical circulation anomalies induced by central Pacific (CP) El Niño cannot totally explain the meridionally elongated circulation anomalies in 2019. Our modeling evidences confirmed the indispensable role of warm SST anomalies over KE region in the 2019 extreme drought’s formation. The projection results show that extreme drought like that in 2019 will occur more (less) frequently under a high (medium-low) emission scenario compared to modern-day level, indicating the urgency of carbon emission reduction.

The Effect of Long-Term Aircraft Parking on Propulsion Units During the Covid-19 Pandemic

Aircraft maintenance is a key factor in air transport. It is essential for any operator to maintain the airworthiness of the aircraft while proceeding according to aviation safety standards. Maintenance involves a number of procedures where it is important that they are performed efficiently and correctly in terms of time. During the Covid-19 pandemic, a large number of aircraft were grounded. Maintenance procedures for these aircraft had to be different than those used during normal operations. In some cases, the insufficient number of qualified maintenance personnel was a major problem. In addition, the large number of aircraft grounded resulted in some of them being parked in locations with unfavorable atmospheric conditions. The objective of this work is to verify the influence of weather conditions on aircraft engines during long-term parking. The experimental verification was conducted using artificially generated atmospheric conditions in the test chamber environment in the presence of salt spray. The aim of this test was to simulate the corrosive effect of the given environment on the selected turbine engine components. The results show what could happen to the turbine engines if certain conditions were not maintained during the long-term aircraft parking at Covid-19. Based on this, the research points to the importance of implementing proper maintenance procedures for long-term aircraft parking. We show how the type of atmosphere in which the aircraft is in for an extended period of time can affect the engines. The results can help identify critical components of turbine engines whose corrosion resistance is inadequate in some cases. As a result, certain maintenance steps can be carried out more efficiently and unnecessary deterioration of engine components due to weathering can be prevented. This can not only increase engine safety and reliability, but also save operators a lot of money.

Exploring the ozone pollution over the western Sichuan Basin, Southwest China: The impact of diurnal change in mountain-plains solenoid

The Sichuan Basin (SCB), to the east of the Tibetan Plateau (TP), experiences severe ozone (O3) pollution. Unfavorable atmospheric diffusion conditions are considered the main causes of heavy air pollution over the basin. However, the meteorological impact of thermally driven mountain-plains solenoid (MPS) between the TP and SCB on O3 pollution has not been reported. Here we show the MPS driving the diurnal O3 changes in the atmospheric boundary layer over the SCB based on surface and high-resolution vertical observations, ERA5 reanalysis data, and the WRF-Chem model. The MPS shifts between upslope and easterly flows along the eastern slope of the TP and SCB during the day and downslope westerly flows to the western SCB at night. The daytime MPS flows drive the westward transport of O3-rich air mass in the atmospheric boundary layer from the polluted SCB and accumulate high O3 levels from the western edge of the SCB to the eastern slope of TP, subsequently aggravating O3 pollution in this region. After sunset, the MPS drainage flows carry air containing elevated O3 eastward downslope along the eastern slope of the TP into the nocturnal residual layer, enhancing the O3 concentrations aloft over the western SCB. The high-level O3 in the residual layer is transported downstream by nocturnal prevailing winds and contributes significantly to the next-day surface O3 buildup in the downwind region through daytime vertical mixing (~30 μg m−3 h−1). The present study reveals a transport mechanism driven by the MPS with coupling diurnal changes in the atmospheric boundary layer, which redistributes O3 over the basin and exacerbates O3 pollution along the western edge of the basin. This study has important implications for understanding meteorological drivers on atmospheric environment underlying the complex terrain.

Overcoming Blade Interference: A Gappy-POD Data Reconstruction Method for Nacelle-Mounted Lidar Measurements

Nacelle-mounted lidar systems suffer data loss due to unfavourable atmospheric conditions such as rain or fog and most importantly the rotation of the blades that obstruct the laser beam from measuring upstream of the turbine. In this paper, we apply Gappy Proper Orthogonal Decomposition (Gappy-POD) to reconstruct incomplete flow fields from nacelle-mounted lidar measurements. For this purpose, two scanning nacelle-based SpinnerLidar simulations are performed inside a Large Eddy Simulation, one measuring the undisturbed wind inflow and the other in the wake of a reference turbine. Data loss of up to 90 % is simulated by artificially removing measurement points. The performance of Gappy-POD in reconstructing the wind fields is evaluated by comparing metrics such as effective wind speeds, vertical shear, yaw misalignment, wake deficit, wake meandering and the turbulent spectra in fixed and rotating frames of reference. We see that Gappy-POD is capable of accurately reconstructing missing data in comparison to normally used spatial interpolation techniques even in cases where 90 % of the data was missing. As a result, the dynamics of the reconstructed wind fields can be investigated based on highly accurate lidar-based wind field retrievals. The methodology can be used as a tool to develop effective wind field reconstruction techniques from sparse data.

Evaluation of Air Pollution Characteristics and Air Quality Improvement Effect in Beijing and Chengdu

In recent years, China's air quality has been improving, and the concentration of atmospheric particulate matter has decreased significantly. In this study, the pollution characteristics and trends of two typical representative cities (Beijing and Chengdu) were analyzed. The geographical locations, pollution emissions, and meteorological diffusion conditions of the two cities were compared, to evaluate the relative contribution of meteorological conditions and pollution reduction regulations in decreasing fine particulate matter (PM2.5) concentrations. The results showed that the number of heavily polluted days and pollution episodes in Beijing and Chengdu decreased significantly from 2013 to 2018, and the concentration of SO2 and PM2.5 decreased substantially. Compared to 2013, SO2 concentration in Beijing and Chengdu has decreased by 77.8% and 70.9%, whereas PM2.5 concentration has decreased by 42.7% and 48.5%, respectively. The largest reduction appeared in winter, when PM2.5 decreased at an annual rate of 13.5 μg ·m-3 for Beijing and 14.1 μg ·m-3 for Chengdu. During the study period, the wind speed in Chengdu was less than that in Beijing, temperature was approximately 3℃ higher, and static wind in winter was more frequent. A significantly lower mixed-layer height, atmospheric capacity index, and ventilation coefficient in Chengdu resulted in more unfavorable atmospheric diffusion conditions. The static and stable weather index and the environmental meteorological index (EMI) also showed that the atmospheric diffusion conditions were better in Beijing than in Chengdu. The EMI of the two cities showed a decreasing trend during the study period, and the decline in EMI in Chengdu was the most significant in 2018, indicating an evident improvement in meteorological conditions. In 2018, emission reductions are estimated to have contributed 33.5% and 24% to the decrease in PM2.5 in Beijing and Chengdu, respectively, and meteorological conditions contributed 7.2% and 11.1% to the reduction in these two cities. In winter, emission reductions respectively contributed 31.7% and 32.5% to reduction in Beijing and Chengdu, while meteorological conditions made a larger contribution.

The Role of the Gulf of Mexico Ocean Conditions in the Intensification of Hurricane Michael (2018)

AbstractHurricane Michael formed on October 7, 2018, in the Northwestern Caribbean Sea, and quickly traveled northward through the Gulf of Mexico, making landfall on the Florida panhandle as a devastating Category 5 hurricane only 3 days later. Before landfall, Michael underwent rapid intensification, despite unfavorable atmospheric conditions. Using observations, we characterized the key ocean features encountered by Michael along its track, which are known for favoring hurricane intensification: high sea surface temperatures, upper ocean heat content and low salinity barrier layer conditions. Ocean observations were consistent with suppressed hurricane‐induced upper ocean cooling, which could only be observed by underwater gliders, and showed that Hurricane Michael constantly experienced sea surface temperatures above 28°C. We carried out ocean Observing System Experiments, which demonstrate that the combined assimilation of in situ and satellite ocean observations into a numerical ocean model led to the most realistic representation of the ocean conditions. They also suggest that, when using the Cooper‐Haines (1996) method to assimilate altimetry observations, assimilating temperature observations is necessary to constrain the model upper ocean vertical structure. We also performed coupled hurricane‐ocean simulations to assess the impact of ocean initial conditions on forecasting Michael. These simulations demonstrate that the ocean conditions, in particular the high sea surface temperatures north of 24°N, played a crucial role in the intensification of Michael. Coupled simulations initialized with the most realistic ocean conditions, constrained by field and satellite observations, show a ∼56% error reduction in wind intensity prior to landfall compared to simulations initialized without data assimilation.

Daily, seasonal, and interannual variability of airborne pollen of Araucaria angustifolia growing in the subtropical area of Argentina

Araucaria angustifolia is an anemophilous conifer native to Southern America threatened with extinction, with a noticeable decrease in its distribution area and seed production. To better understand the reproductive dynamics, the aerobiological curves obtained with Hirst methodology were analyzed during 7 years in San Antonio (Misiones, Argentina), including productivity, seasonality, start, end, duration, and peak, along with the role of meteorological/seasonal climate factors. An alternation between 1 year of high pollen values (1685 pollen grains day m−3, on average), followed by 2 years of a progressive reduction (456 pollen grains day m−3, on average) in productivity, was observed. This pattern was negatively related to temperature during the month preceding pollination; August minimum temperature yielded the best fit (correlation coefficient r = − 0.9, p < 0.01). In only 36 days, including October, 90% of the annual pollen was released. The daily pattern showed a curve with higher concentrations between hour 8 and hour 14. The daily maximum at hour 10 suggests pollen inputs from local sources. The eolic transport is limited due to the big size and weight of the grains and the unfavorable atmospheric conditions that prevail in this subtropical forest (high humidity and low wind speed). The average airborne pollen curve showed a peak during the second fortnight of October. Rain induced a noticeable reduction in pollen concentration modifying the shape of the aerobiological curve. Aerobiological analyses provide reliable information for the design of conservation strategies, such as ex situ planting and selective harvesting of seeds.

SOLUTIONS ENSURING SAFETY DURING TRANSPORT OF STATE VIPS BY MILITARY AIRFCRAFT (part 2)

It should be noted that due to the good of the state (the so-called “national interest”), in the case of transport of VIPs by military aircraft, its acceptable level of risk is lower than in the case of transportation of other passengers. Thus, normative documentation regarding such transport regulates a significantly wider and more extensively indicated range of issues, including the principle of “security above all”, when compared to transportation of other passengers. The regulations contained in the normative documents concerning transportation of state VIPs by military aircraft are to protect them not only from human errors which may have influence on the occurrence of air incidents in the course of such transportation. Normative documents also regulate additional requirements regarding aviation equipment employed to transport state VIPs by military aircraft (to decrease the risk of failure) and an in-depth analysis of environment factors (to decrease the risk related to threats to security of transportation due to unfavourable atmospheric conditions).

Odour Emissions of Municipal Waste Biogas Plants—Impact of Technological Factors, Air Temperature and Humidity

Biogas plants processing municipal waste are an important part of a circular economy (energy generation from biogas and organic fertiliser production for the treatment of selectively collected biowaste). However, the technological processes taking place may be associated with odour nuisance. The paper presents the results of pilot research conducted at six municipal waste biogas plants in Poland. It shows the relations between odour intensity and concentration and the occurring meteorological and ambient conditions (air temperature and relative humidity) and technological factors at biogas plants processing municipal waste. The impact of meteorological and ambient conditions was identified by measuring air temperature and relative humidity and observing their changes. The impact of technological factors was identified by measuring odorant concentration (volatile organic compounds and ammonia) and observing their changes between individual measurement series. At most analysed biogas plants, the influence of technological factors on odour emissions took place and was clearly noted. The elements of biogas installations characterised by the highest concentration of these odorants were indicated. Special attention should be paid to the choice of technological solutions and technical and organisational measures to reduce the impact of unfavourable atmospheric conditions on odour emissions.

C-RAN With Hybrid RF/FSO Fronthaul Links: Joint Optimization of Fronthaul Compression and RF Time Allocation

This paper considers the uplink of a cloud radio access network (C-RAN) comprised of several multi-antenna remote radio units (RUs) which compress the signals that they receive from multiple mobile users (MUs) and forward them to a CU via wireless fronthaul links. To enable reliable high rate fronthaul links, we employ a hybrid radio frequency (RF)/free space optical (FSO) system for fronthauling. Moreover, to strike a balance between complexity and performance, we consider three different quantization schemes at the RUs, namely per-antenna vector quantization (AVQ), per-RU vector quantization (RVQ), and distributed source coding (DSC), two different RF fronthaul transmission modes, namely orthogonal transmission and non-orthogonal transmission, and two different detectors at the CU, namely the linear minimum mean square error detector and the optimal successive interference cancellation detector. For this network architecture, we investigate the joint optimization of the quantization noise covariance matrices at the RUs and the RF time allocation to the multiple-access and fronthaul links for rate region maximization. To this end, we formulate a unified weighted sum rate maximization problem valid for each possible combination of the considered quantization, RF fronthaul transmission, and detection schemes. To handle the non-convexity of the unified problem, we transform it into a bi-convex problem which facilitates the derivation of an efficient suboptimal solution using alternating convex optimization and golden section search. Moreover, by introducing a backoff parameter to reduce the probability of infeasibility, we generalize the proposed optimization framework to account for imperfect channel estimation. Our simulation results show that for each combination of the considered quantization, RF fronthaul transmission, and detection schemes, C-RAN with hybrid RF/FSO fronthauling can achieve a considerable sum rate gain compared to conventional systems employing pure FSO fronthauling, especially under unfavorable atmospheric conditions. In addition, employing a more sophisticated quantization scheme can significantly improve the system performance under adverse atmospheric conditions. In contrast, in clear weather conditions, when the FSO link capacity is high, the simple AVQ scheme performs close to the optimal DSC scheme. Furthermore, our simulation results suggest that the proposed algorithm can be adapted to the quality of the channel estimates by tuning the backoff parameter.

Analysis of effectiveness of the program of joined air traffic controlles and pilotes training

Training of cadets-air traffic controllers and cadets-pilots is an integral part of the training, which allows you to form the skills of quick and correct decision-making in different types of situations. For the air traffic controller, these are exercises to solve conflict situations with aircraft in the area of their responsibility, solving problems in normal flight conditions, in unfavorable atmospheric conditions and in the non-routine situations in flight. For the pilots, solutions to the problems are reduced to the rapid decisionmaking on aircraft control in normal flight conditions, adverse atmospheric conditions and non-routine situations in flight. As you know, the work of air traffic controllers is associated with the work of pilots, but training in educational institutions takes place separately, resulting in gaps in knowledge of the specifics of the adjacent specialty, and, eventually, leads to errors. Optimization of the educational process is currently an urgent task. The program of joint training can act as an optimization tool. The program enables you to collaboratively practice the skills of fast decision-making, clearly to learn the specifics of the related specialties that will allow you to create a complete picture of the air situation. The program of joint training implies the joint operational logic simulator that combines two simulators. For the air traffic controller, this is a separate airspace area in the form of a sector, for the pilot it is the cockpit. Thus, the solution to the problems occurs sequentially from the air traffic controller to the pilot and vice versa, and the controller has the ability to observe the algorithm of the pilot's actions, and the pilot is able to monitor the algorithm of the controller's actions.

Landscape‐dependent time versus energy optimizations in pelicans migrating through a large ecological barrier

Abstract During migration, birds are often forced to cross ecological barriers, facing challenges due to scarcity of resources and suitable habitats. While crossing such barriers, birds are expected to adjust their behaviour to reduce time, energy expenditure and associated risks. We studied the crossing of the Sahara Desert by the Great White Pelican (Pelecanus onocrotalus), a large wetland‐specialist. We focused on decisions made by migrating pelicans along different parts of the southbound autumn migration, their response to local environmental conditions and the implications for time and energy optimizations. We compared the observed pelicans' migration routes with simulated ‘direct‐pass’ (shortest, mostly across the desert) and ‘corridor‐pass’ (along the Nile River) routes, and used GPS, body acceleration and atmospheric modelling to compare flight behaviour along the Nile River versus the desert. The observed route was significantly shorter and faster than the simulated corridor‐pass route and not significantly different from the simulated direct‐pass one. Daily flights over the desert were longer than along the Nile River, with flying time extending to late hours of the day despite unfavourable atmospheric conditions for soaring–gliding flight. Moreover, the pelicans' behavioural response to atmospheric conditions changed according to the landscape over which they flew. Overall, the pelicans showed stronger behavioural adjustments to atmospheric conditions over the desert than along the Nile River. Our findings suggest that migrating pelicans primarily acted as time minimizers while crossing the Sahara Desert, whereas energetic optimization was only considered when it did not substantially compromise time optimization. The pelicans took the almost shortest possible route, only following the Nile River along its south‐oriented parts, and frequently staged overnight in the desert far from water, despite being large, wet‐habitat specialists. Correspondingly, their behavioural response to atmospheric conditions changed according to the landscape over which they were flying, switching between time (over the desert) and energy (over the Nile River) optimization strategies. Our results suggest that the interaction between landscape and atmospheric conditions depict a flexible, yet primarily time‐dominated, migration optimization strategy. A free Plain Language Summary can be found within the Supporting Information of this article.

Enhancing the Aesthetics and Transportability of Container-Kiosk in Ghana

Over the years, container-kiosk have been used in Ghana as point of sale joints where various services are carried out. Although the initial intent of these temporary structures are purposely for sales, there has been a pressing need for owners of such structures to use them for both business and as an abode. This is as a result of the high cost of accommodation in our cities and over-crowding in these cities due to rural-urban migration. Aside defeating the primary use of these structures, they have not been designed and fabricated for easy transportability. These temporary structures both deface the environmental aesthetics of our cities and incur high financial burden on owners and the state when being transported or relocated. The objective of this research was to redesign container-kiosk with much emphasis on their beauty and demountability for easy transportability. The research employed the descriptive and studio based research design and used observation and interview to soliciting information from a sample size of 186, drawn from an accessible population size of 372. Explorations were made into the nature of materials used for fabricating these container-kiosks. It was found that mild steel rust faster than galvanize steel and also majority of these container-kiosk owe their rust to the concrete pedestal upon which they are mounted as well as unfavourable atmospheric conditions. Is was again found that much effort had not been made to improve the Aesthetics as well as the ease with which these temporary structure can be demounted, rather artisans copied the form in which ISO shipping containers have been formed. It is therefore recommended that design concepts and findings of this research be considered when constructing Demountable containers.

Physical factors in the hermetic SuperGrainBag® and effect on the larger grain borer [Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)] and aflatoxin production by Aspergillus flavus during the storage of ‘Obatanpa’ maize (Zea mays L.) variety

Controlling invasive pests and aflatoxin production by moulds in stored grains is a global challenge to food security and public health, particularly in Africa. Food storage systems are designed to provide constraints to spoilage organisms by presenting mechanical barrier or unfavourable atmospheric conditions to their growth and productivity. This study examined the physical factors generated in hermetic SuperGrainBags® during the storage of ‘Obatanpa’ variety of maize (Zea mays L.) and the effect on growth of the larger grain borer Prostephanus truncatus (Horn) and aflatoxin contamination by Aspergillus flavus. Cultured P. truncatus or A. flavus was introduced into 1.5 kg of the dried maize and stored in either hermetic SuperGrainBags® or non-hermetic polypropylene bags. The hermetic conditions elicited an increase in the interstitial temperature (ca. 27 °C) but a decrease in the relative humidity (<70%), oxygen concentration (<6.4%) and the grain moisture content (<13.7%), the combined effects of which inhibited growth of the insects and aflatoxin production by the moulds. Total mortality of P. truncatus occurred after 52 d of storage in the SuperGrainBags® while aflatoxins concentration remained within safe limits for human consumption. In contrast, there was proliferous growth of P. truncatus and significant increase in aflatoxin concentration to lethargic levels within the polypropylene bags where temperature, relative humidity and grain moisture increased significantly. Accordingly, grain damage and weight loss percentages were significantly high in the polypropylene bags while that in the SuperGrainBags® were negligible. Altogether, the SuperGrainBags® better preserved the maize grain quality and safeguarded it against health risks than the polypropylene bags.

Early arrival at breeding grounds: Causes, costs and a trade‐off with overwintering latitude

Early arrival at breeding grounds is of prime importance for migrating birds as it is known to enhance breeding success. Adults, males and higher quality individuals typically arrive earlier, and across years, early arrival has been linked to warmer spring temperatures. However, the mechanisms and potential costs of early arrival are not well understood. To deepen the understanding of arrival date differences between individuals and years, we studied them in light of the preceding spring migration behaviour and atmospheric conditions en route. GPS and body acceleration (ACC) data were obtained for 35 adult white storks (Ciconia ciconia) over five years (2012-2016). ACC records were translated to energy expenditure estimates (overall dynamic body acceleration; ODBA) and to behavioural modes, and GPS fixes were coupled with environmental parameters. At the interindividual level (within years), early arrival was attributed primarily to departing earlier for migration and from more northern wintering sites (closer to breeding grounds), rather than to migration speed. In fact, early-departing birds flew slower, experienced weaker thermal uplifts and expended more energy during flight, but still arrived earlier, emphasizing the cost and the significance of early departure. Individuals that wintered further south arrived later at the breeding grounds but did not produce fewer fledglings, presumably due to positive carry-over effects of advantageous wintering conditions (increased precipitation, vegetation productivity and daylight time). Therefore, early arrival increased breeding success only after controlling for wintering latitude. Males arrived slightly ahead of females. Between years, late arrival was linked to colder temperatures en route through two different mechanisms: stronger headwinds causing slower migration and lower thermal uplifts resulting in longer stopovers. This study showed that distinct migratory properties underlie arrival time variation within and between years. It highlighted (a) an overlooked cost of early arrival induced by unfavourable atmospheric conditions during migration, (b) an important fitness trade-off in storks between arrival date and wintering habitat quality and (c) mechanistic explanations for the negative temperature-arrival date correlation in soaring birds. Such understanding of arrival time can facilitate forecasting migrating species responses to climate changes.

Analysis of Performance of Short Tree Logging with Farm Tractor and Logging Trailer

Abstract The paper presents analysis of efficiency of the logging unit comprising Belarus 820 farm tractor and PD80 logging trailer equipped with Ryś-1 crane. Analysis was made based on the working day timing. The unit logged 1- meter long tree pieces (hornbeam, oak, birch) from the area where material for logging was distributed irregularly on the entire felling site. Unfavourable atmospheric conditions were reported during the working day (a thick layer of snow, low temperature, not frozen soil) which could have influenced the unit operation performance. Despite that the performance of the logging unit was comparable to similar logging units described in the literature. Determined coefficient of use of the operating time of the machine K02 was 0.93, coefficient of use of the shift working time K04 − 0.9, coefficient of use of the shift exploitation time K07 − 0.8. Hourly performance in the shift exploitation time was 4.98 m3·h−1, efficiency in the shift working time W02 − 4.80 m3·h−1 and performance in the general shift time W07 − 4.30 m3·h−1.

Air stagnation and its impact on air quality during winter in Sichuan and Chongqing, southwestern China

The Sichuan and Chongqing regions suffer from severe haze weather in winter due to the unfavourable atmospheric diffusion conditions. Reanalysis and precipitation datasets were applied in this study to calculate and distinguish air stagnation events using a developed criterion, and the impacts of the occurrence of air stagnation events on air quality were analysed in combination with the PM2.5 concentration data for the winters of 2013–2016. The highest occurrence frequency of air stagnation events was observed in 2013, and the lowest, 2015. The meteorological conditions during winter in the Sichuan Basin were inclined to form unfavourable atmospheric diffusion conditions, and the occurrence frequency of air stagnation days was up to 76.6% on average during the four winters. The effects of air stagnation events on air quality were most obvious in the western and southern Sichuan Basin. The mean concentrations of PM2.5 during air stagnation days were higher by 41.9% than those during non-air stagnation days. The PM2.5 concentrations were adjusted using the favourable atmospheric diffusion conditions in 2015 as a baseline to quantify the PM2.5 contribution to the improvement of air quality in the other years, which revealed that the level of PM2.5 in the Sichuan and Chongqing regions was declining at a rate of approximately 10.7% overall during the winters of 2013–2016, implying that the air pollutant reduction measures have been highly effective. Furthermore, the occurrence frequency of air stagnation days and events were increased in recent ten years of 2007–2016, with linear slopes of 0.61yr−1 and 0.26yr−1, respectively. The study revealed that the government might face a greater challenge in improving the air quality over winter and should pay more attention to reduction of pollutant emission in areas of Chengdu, Chongqing and cities in the south of the Sichuan Basin.

Simulation of chemical accidents with acetylene in 'Messer Tehnogas' Kraljevo plant by 'ALOHA' software program

Chemical plants are generally associated with potentially high risk of chemical accidents. During chemical accidents hazardous substances jeopardize human lives, destroy material assests and degrade natural environment. The release of flammable and explosive gases or liquids especially poses a significant threat to the environment. This paper introduces the simulation of a chemical accident caused by an uncontrolled acetylene cylinder release in the warehouse of Messer Tehnogas Kraljevo chemical plant. The simulation was performed by ALOHA program package which defines a possible accident development and determines threat and safety zones. The assessment of potential scenarios is based on physico-chemical properties of the substance causing the accident. This paper discusses accident situations occurring under the most unfavorable atmospheric conditions.