External Meteorological Conditions Research Articles

A Finite-Element-Analysis-Based Feasibility Study for Optimizing Pantograph Performance Using Aluminum Metal Matrix Composites

A pantograph is a key component on the tops of trains that allows them to efficiently tap electricity from power lines and propel them. This study investigates the possibility of using metal matrix composites (MMCs), specifically aluminum MMCs, as a material for making pantograph parts regarding the dynamics of the train’s movement and external meteorological conditions. In this study, a computer-aided design (CAD) model is created using PTC Creo design software and moves to detailed finite element analysis (FEA) simulations executed by the ANSYS software suite. These simulations are important in examining how the dynamic performance of pantographs can vary. The incorporation of Al MMC materials into the structure of the pantograph resulted in significant improvements in structural robustness, with equal stress reduced by up to 0.18%. Similarly, aluminum MMC materials reduced the strain energy by 0.063 millijoules. The outcomes not only give a new perspective to the implementation of modern materials but also provide a breakthrough concept to improve efficiency and increase the service life of pantographs. This study marks a significant milestone in the theoretical development of essential train systems, furnishing eminent perspectives toward the tactical development of transportation infrastructure by suggesting new avenues for the smooth incorporation of smart materials in railway transportation, which would contribute to a more sustainable and reliable future.

Seasonal Fluctuations in Hemodynamic Characteristics in Patients with Increased Meteosensitivity: a Survey

INTRODUCTION. Currently, the Russian Federation occupies one of the first places among the developed countries of the world in terms of mortality from cardiovascular diseases, 3–5 times higher than in developed countries. Arterial hypertension, smoking, diabetes mellitus, obesity, and other risk factors contribute to the onset and progression of cardiovascular diseases, and lifestyle modification and reduction in risk factor levels can slow their development. An increase in physical activity along with a decrease in the total calorie content of food is mandatory for reducing body weight. When combining physical exercises with climatotherapy (health path, physical exercises in the open air), it is necessary to take into account external meteorological conditions, as well as increased meteosensitivity of some patients, which are able to neutralize the therapeutic effects achieved by using, for example, health path.
 AIM. To study the frequency and seasonality of the main meteopathic reactions in patients with cardiovascular diseases.
 MATERIALS AND METHODS. We conducted a verbal and communicative examination of 735 patients with a body mass index of 25 kg/m2 and over, who were treated in the health resort complex “Vulan“. The analysis of patients’ answers about arterial pressure increases and complaints about other meteopathic reactions during the year according to self-monitoring data was carried out. Macroclimatic characteristics of the location of the health resort complex were also studied. The study was performed as part of the research work under the state assignment of the Ministry of Health of the Russian Federation, reg. No. 121040200110-0.
 RESULTS. It was revealed that the highest frequency of increased blood pressure recorded by patients is registered in March, October, November and December, the lowest is recorded in May, June and August. At the same time, the frequencies of other meteopathic reactions, such as fear, anxiety, shortness of breath, and others, are evenly distributed throughout the year.
 CONCLUSION. The study evaluated the natural climatic factors of the resort located on the Black Sea coast of the North Caucasus, by the example of the health resort complex “Vulan“ in connection with the search of favorable seasons for the treatment of cardiological patients with increased meteosensitivity. The results obtained allow us to make proposals to supplement the current regulatory documents with the data on the identified favorable periods of health resort treatment for cardiologic patients, expanding the seasonality for referring patients to the resorts of the Black Sea coast of the North Caucasus.

Frequency and severity of meteoropathic reactions in patients with excess body weight associated with cardiovascular diseases

Obesity is a widespread multifactorial, multisystem disease associated with a high incidence of cardiovascular diseases. Dosed physical activity is one of the main therapeutic measures for this category of patients. The combination of physical training with climatotherapy (terrain therapy) accumulates a therapeutic effect. However, it is necessary to take into account the external meteorological conditions and meteotropic reactions that occur in patients, which can neutralize the achieved therapeutic effect. The purpose of the study was to investigate the prevalence of meteoropathic reactions in patients who arrived for resort treatment, their association with comorbidities,and interdependence with the region of permanent residence. In order to determine the severity of meteoropathic reactions and their main manifestations, a cross-sectional study was conducted, involving 735 patients with a body mass index of 25–29.9 kg/m2 or higher who were treated at the Resort Complex «Vulan» in the period from February 1, 2021 to April 1, 2022. As a tool for assessing meteoropathic reactions, a retrospective questionnaire «Meteoropathy» (research work No. A AAA-A18‑118022890045‑6) was used.

State and development of grain storage engineering and technologies in Ukraine

Topicality. These researches are due to the grain storage problem, the features of maize grain storage in metal silos under the various environmental factors, as well as more efficient using the material and technical facilities, including the grain storages of new generation. Purpose. To establish the types of grain storage facilities that are most appropriate for storing the yield of different crops, to improve metal silos and maize grain storage technologies. Materials and Methods. During experiments on maize grain storage, we used the metal silo equipped with a system of sensors to measure the temperature in different places of grain heap. We studied two models of grain storages, such as a standard construction (control) and an experimental one thermal isolated with a polyurethane layer. During the storage experiment, grain quality was monitored on grain moisture content, dockage, damage and germination. Results. Different types of grain storage facilities storing main volume of grain harvest were characterized; the technical, economic and technological advantages and disadvantages of grain storage were highlighted; directions for further development are outlined. The features of maize grain storage in the metal silos under influence of external meteorological conditions for 60 day were established. Temperature fluctuations were 7.1–13 °С in grain storage with thermal insulation, 4.5–25.9 °С – without insulation. As a result of significant temperature fluctuations, the grain was moistened by 2.2 %, its acidity increased by 1 degree, germination decreased by 7 %. At the stage of preparation for storage, maize grain should be cleaned to purity of 93–97 % by removing grain impurities. An effective method for this is fractional separation of grain. Conclusions. Thermal insulation of metal silos significantly reduces the negative impact of fluctuations in ambient air temperature, stabilizes the storage mode, and ensures high quality maize grain. The stability of grain during storage increases in the case of selection from it a fraction of grain of small, unfilled, with a low 1000 grain weight. Key words: types of grain storage facilities, metal silo, thermal insulation, maize, quality, cleaning grain before storage

Model and Simulation of a Floating Hybrid Wind and Current Turbines Integrated Generator System, Part I: Kinematics and Dynamics

This initial publication is part of a series of publications that will appear soon, which pursue a final objective for the proposal of a fully integrated and controlled hybrid system composed of a floating wind turbine—type “OC3-Hywind”—and two marine current turbines with the aim of increasing the energy generated by the floating installation and, at the same time, use the set of turbines as actuators as part of an integral cooperative control system of the floating hybrid system to ensure the structural stability of the floating hybrid generator system (FHGS) in harsh weather conditions, which is a key issue in this type of floating systems. A specially designed tool to design, analyze, and control this type of FHGSs was developed using Matlab®. In this tool, named Floating Hybrid Generator Systems Simulator (FHYGSYS), several tests were carried out on the structural stability of the system considering the interactive phase of the acting forces. Working in a programming environment like Matlab® allows design freedom and the possibility of evaluating the system with different geometries, aerodynamic airfoils, and external meteorological conditions, and also including or eliminating certain elements, etc. This versatility will be helpful in future studies aimed at evaluating this system and maximizing the production of energy.

Temperature evolution in heated premises and external boundary wall with dynamic control of heating systems

Abstract The study presents a mathematical model for building heating control. The buildings are connected to district heating or to central heating. The task of the heating control is to maintain a preset constant indoor air temperature. Control disturbance is caused by external meteorological conditions, firstly by outdoor air temperature. The control action can be the change in heat transfer capacity of the radiators, whereby the indoor air temperature can be commanded back to the present value to offset the effect of the disturbance. Just the control can be a follower or of predictive type. The expected indoor air temperature can be calculated from the energy balances. These are composed of differential equations, describing dynamic equilibrium of heat transfer through the external walls, as well as heat storage in the walls and indoor air. Type of differential equations is linear, inhomogeneous, of first or second order. Solution of the differential equation results in describing the change in indoor air temperature in time as a function of outdoor air temperature. Further on, the equation determines the function of the necessary heating capacity to keep the indoor air temperature constant. By the model several heating programs can be evaluated. The physical model is shown in Fig. 1. Intermediate variable is the average temperature of the external walls. Heat conduction and convection through the walls is calculated by the difference of the indoor air temperature and of the average wall temperature by using relevant R 1 and R 2 heat resistance factors. The model is adequate when the heat transport within the building sections is neglectable, and the thermodynamic and heat transfer characteristics of the walls are identical. Thereby the model describes the heat balance of representative premises, but the results can be transferred to similar other premises, too.

Lake thermal structure drives interannual variability in summer anoxia dynamics in a eutrophic lake over 37 years

Abstract. The concentration of oxygen is fundamental to lake water quality and ecosystem functioning through its control over habitat availability for organisms, redox reactions, and recycling of organic material. In many eutrophic lakes, oxygen depletion in the bottom layer (hypolimnion) occurs annually during summer stratification. The temporal and spatial extent of summer hypolimnetic anoxia is determined by interactions between the lake and its external drivers (e.g., catchment characteristics, nutrient loads, meteorology) as well as internal feedback mechanisms (e.g., organic matter recycling, phytoplankton blooms). How these drivers interact to control the evolution of lake anoxia over decadal timescales will determine, in part, the future lake water quality. In this study, we used a vertical one-dimensional hydrodynamic–ecological model (GLM-AED2) coupled with a calibrated hydrological catchment model (PIHM-Lake) to simulate the thermal and water quality dynamics of the eutrophic Lake Mendota (USA) over a 37 year period. The calibration and validation of the lake model consisted of a global sensitivity evaluation as well as the application of an optimization algorithm to improve the fit between observed and simulated data. We calculated stability indices (Schmidt stability, Birgean work, stored internal heat), identified spring mixing and summer stratification periods, and quantified the energy required for stratification and mixing. To qualify which external and internal factors were most important in driving the interannual variation in summer anoxia, we applied a random-forest classifier and multiple linear regressions to modeled ecosystem variables (e.g., stratification onset and offset, ice duration, gross primary production). Lake Mendota exhibited prolonged hypolimnetic anoxia each summer, lasting between 50–60 d. The summer heat budget, the timing of thermal stratification, and the gross primary production in the epilimnion prior to summer stratification were the most important predictors of the spatial and temporal extent of summer anoxia periods in Lake Mendota. Interannual variability in anoxia was largely driven by physical factors: earlier onset of thermal stratification in combination with a higher vertical stability strongly affected the duration and spatial extent of summer anoxia. A measured step change upward in summer anoxia in 2010 was unexplained by the GLM-AED2 model. Although the cause remains unknown, possible factors include invasion by the predacious zooplankton Bythotrephes longimanus. As the heat budget depended primarily on external meteorological conditions, the spatial and temporal extent of summer anoxia in Lake Mendota is likely to increase in the near future as a result of projected climate change in the region.

Relationships among local-scale urban morphology, urban ventilation, urban heat island and outdoor thermal comfort under sea breeze influence

Many cities are facing the problem of urban heat island (UHI) and UHI mitigation is becoming crucial in urban planning and design. The reasonable wind-sensitive design may be a feasible approach to UHI mitigation and outdoor thermal comfort improvement, as cool wind (i.e. sea breeze) is a good cooling intervention. Consistent with the precinct ventilation zone scheme, this study experimentally investigated relationships among urban morphology, precinct ventilation performance, UHIs and outdoor thermal comfort in a compact high-rise gridiron precinct in the coastal Sydney, Australia.Results indicate that precinct morphological characteristics had a strong modification effect on precinct ventilation. As a result, under different combination of external meteorological conditions and precinct morphological characteristics, there was no significant difference in precinct ventilation performance (i.e. relative wind velocity ratio). The precinct ventilation performance forced by sea breeze could significantly mitigate UHIs. Meanwhile, the precinct ventilation performance forced by the sea breeze could significantly improve relative humidity which could further significantly improve outdoor thermal comfort. The street orientation was no longer a critical factor affecting precinct ventilation performance, UHIs and outdoor thermal comfort at the precinct scale.Overall, this study preliminarily revealed precinct ventilation performance and its influence on UHIs and outdoor thermal comfort. The cooling and humidifying effects of wind background cannot be ignored in microclimate studies and should be considered for microclimate regulation in urban planning and design.

Numerical study of the greenhouse solar drying of olive mill wastewater under different conditions

The aim of this work is to develop thermal modeling of the olive mill wastewater drying process in a greenhouse solar dryer. A configuration was thus proposed and simulated using the commercial software COMSOL Multiphysics in order to solve the conservation equations governing our problem. The resulting simulations are used to evaluate the temperature, velocity, and vapor mass fraction distributions after hours of sunshine and to provide a quantification of the drying process. The influence of the greenhouse effect on the drying kinetics is highlighted by comparing to open sun-drying results. The effect of some greenhouse geometric characteristics and external meteorological conditions are studied.

Urban ventilation and its potential for local warming mitigation: A field experiment in an open low-rise gridiron precinct

The reduction of urban ventilation is one of the significant causes of the urban heat island (UHI) phenomenon. Reasonable urban planning and design can guide cooler wind into cities, thereby mitigating UHI phenomenon. However, existing knowledge of the cooling effect of urban ventilation is mainly at the regional or city scale, while the lack of information on ‘realistic’ precinct ventilation limits the use of wind for UHI mitigation. Therefore, this study aims to understand the precinct ventilation and its associated influences on UHI effects and outdoor thermal comfort. In specific, a case study analysis was performed in summer in a precinct of the coastal Sydney, Australia. Results indicate that in the open low-rise gridiron precinct, the precinct ventilation performance (PVP), precinct outdoor thermal environment (POTE) and precinct outdoor thermal comfort (POTC) significantly varied with the combination of external meteorological conditions and precinct morphological characteristics, while the street orientation made insignificant influence to PVP, POTE and POTC. The PVP exhibited its significant potentials for UHII reduction and POTC improvement. The PVP forced by the sea breeze could further enhance relative humidity for UHII reduction and POTC improvement. Overall, this study presents the understanding of PVP and the associated influence on POTE and POTC under realistic and complicated precinct context. It can further facilitate wind-sensitive urban planning and design for local warming mitigation.

Wind-sensitive urban planning and design: Precinct ventilation performance and its potential for local warming mitigation in an open midrise gridiron precinct

Urban heat island (UHI) phenomenon is a severe issue faced by many cities and the reduction of urban ventilation is one of the significant causes. Reasonable urban planning and design can allow cooler wind penetration and thereby UHI mitigation. Upon the local climate zone, the precinct ventilation zone is developed at the local scale with the consideration of wind influence during planning and design. Nevertheless, the precinct ventilation performance (PVP) and its potential influence on precinct outdoor thermal environment (POTE) and precinct outdoor thermal comfort (POTC) have not been well understood. As a result, this study aims to examine PVP and its associated influence on POTE and POTC. This is achieved by a case study within an open midrise gridiron (OMG) precinct in Sydney, Australia during summertime. Result indicates the combinations of the OMG precinct with different external meteorological conditions (EMC) resulted in significant variations in PVP, POTE and POTC. Street orientation in the OMG precinct was not a determinant of PVP, POTE and POTC variations. Compared with the inland wind, sea breeze resulted in weaker UHII within the OMG precinct and more areas underwent cool island effects. Nevertheless, wind could not fully explain the variation of POTE and POTC, while it still had cooling potentials under specific conditions. When the sea breeze prevailed, wind exhibited its cooling potential under the combination of negative UHII and shading as well as that of positive UHII and solar exposure. Forced by the inland wind, precinct ventilation could still have cooling potential under positive UHII and solar exposure combination. Moreover, for cities like Sydney with not high air moisture, moisture increase could result in UHI mitigation and POTC improvement, which was also a way of sea breeze cooling under certain conditions. Afterwards, some implications for local warming mitigation through precinct planning and design have been presented. Overall, this study provides the understandings of the PVP and its associated influence on POTE and POTC within the OMG precinct, and can practically inform urban planners and designers with the wind-sensitive urban planning and design for local warming mitigation.

Photovoltaic Array Fault Diagnosis Based on Gaussian Kernel Fuzzy C-Means Clustering Algorithm.

In the fault diagnosis process of a photovoltaic (PV) array, it is difficult to discriminate single faults and compound faults with similar signatures. Furthermore, the data collected in the actual field experiment also contains strong noise, which leads to the decline of diagnostic accuracy. In order to solve these problems, a new eigenvector composed of the normalized PV voltage, the normalized PV current and the fill factor is constructed and proposed to characterize the common faults, such as open circuit, short circuit and compound faults in the PV array. The combination of these three feature characteristics can reduce the interference of external meteorological conditions in the fault identification. In order to obtain the new eigenvectors, a multi-sensory system for fault diagnosis in a PV array, combined with a data-mining solution for the classification of the operational state of the PV array, is needed. The selected sensors are temperature sensors, irradiance sensors, voltage sensors and current sensors. Taking account of the complexity of the fault data in the PV array, the Kernel Fuzzy C-means clustering method is adopted to identify these fault types. Gaussian Kernel Fuzzy C-means clustering method (GKFCM) shows good clustering performance for classifying the complex datasets, thus the classification accuracy can be effectively improved in the recognition process. This algorithm is divided into the training and testing phases. In the training phase, the feature vectors of 8 different fault types are clustered to obtain the training core points. According to the minimum Euclidean Distances between the training core points and new fault data, the new fault datasets can be identified into the corresponding classes in the fault classification stage. This strategy can not only diagnose single faults, but also identify compound fault conditions. Finally, the simulation and field experiment demonstrated that the algorithm can effectively diagnose the 8 common faults in photovoltaic arrays.

A New Security Warning Model about Power Grid

In recent years, lots of power grid blackouts at home and abroad indicates that the meteorological disasters caused by external meteorological conditions has gradually rose to major contradiction of power grid security. Basing on release information of meteorology, lightning monitoring information and power transmission equipment monitoring information, it established a weather warning model about power grid security, combined with real-time security analysis. Firstly, mathematical models of various types of weather conditions and weather risk assessment model grid were built, then actual operating conditions of a certain regional power grid and model results were compared, the comparison result prove the accuracy of the warning model, and provides a strong recommendation for decision-making.

Heterogeneous treatment effects of safe water on infectious disease: Do meteorological factors matter?

Mortality from waterborne infectious diseases remains a serious issue globally. Investigating the efficient laying plan of waterworks to mitigate the risk factors for such diseases has been an important research avenue for industrializing countries. While a growing body of the literature has revealed the mitigating effects of water-purification facilities on diseases, the heterogeneous treatment effects of clean water have been understudied. The present study thus focuses on the treatment effect heterogeneity of piped water with respect to the external meteorological environment of cities in industrializing Japan. To estimate the varying effects, we implement fixed-effects semivarying coefficient models to deal with the unobservable confounding factors, using a nationwide city-level panel dataset between 1922 and 1940. We find evidence that the magnitude of safe water on the reduction in the typhoid death rate is larger in cities with a higher temperature, which is consistent with recent epidemiological evidence. These findings underscore the importance of the variations in the external meteorological conditions of the municipalities that install water-purification facilities in developing countries.

High-Order Sliding Mode Control of Greenhouse Temperature

<p>This paper deals with the design and implementation of the high order sliding mode controller to control temperature greenhouse. The control objective aims to ensure a favorable microclimate for the culture development and to minimize the production cost. We propose performing regulation for the greenhouse internal temperature based on the second order sliding mode technique known as Super Twisting Algorithm (STA). This technique is able to ensure robustness with respect to bounded external disturbances. A successful feasibility study of the proposed controller is applied to maintien a desired temperature level under an experimental greenhouse. The obtained results show promising performances despite changes of the external meteorological conditions.</p>

Heliogreenhouse Ground Temperature Forecasting Technology Research

Based on the comparison and observations of the internal and external meteorological conditions of the heliogreenhouse, BP neural network, stepwise regression and energy balance principle were used, respectively, to construct the greenhouse air temperature prediction model. The results showed that although the BP neural network- based prediction model had a high forecasting accuracy, due to the comparatively different growth characteristics of cultivated crops, there was a lack of wide adaptability of services; the mechanism of the prediction model constructed by the energy balance principle was strong, but it was difficult to obtain the relevant parameters and had a poor prediction accuracy and a short effective service period; the greenhouse temperature prediction model constructed by the stepwise regression had a comparative advantage over the previous two models and the forecasting effectiveness can be for the next 1-7 days.

Heliogreenhouse Air Temperature Forecasting Technology Research

Based on the comparison and observations of the internal and external meteorological conditions of the heliogreenhouse, BP neural network, stepwise regression and energy balance principle were used, respectively, to construct the greenhouse air temperature prediction model. The results showed that although the BP neural network-based prediction model had a high forecasting accuracy, due to the comparatively different growth characteristics of cultivated crops, there was a lack of wide adaptability of services; the mechanism of the prediction model constructed by the energy balance principle was strong, but it was difficult to obtain the relevant parameters and had a poor prediction accuracy and a short effective service period; the greenhouse temperature prediction model constructed by the stepwise regression had a comparative advantage over the previous two models and the forecasting effectiveness can be for the next 1-7 days.

Greenhouse climate modelling and robust control

This paper deals with the problem of modelling and control of greenhouses inside climate defined by two variables: the temperature and hygrometry. The control objective aims to ensure a favourable inside microclimate for the culture development and to minimize the production cost. Achieving this objective is difficult, due to the complexity of the phenomena involved in the plant growth process: the two variables are correlated and very sensitive to the outside weather and also to many other practical constraints (actuators, moistening cycle …). We propose highly performing regulation for the greenhouse internal state based on H 2 robust control design. It involves a linear control model of the process, obtained by an off-line parametric identification technique. Evaluation of control performance is achieved through a benchmark physical model derived from energy balance for the temperature and water mass balance for the hygrometry. The main steps in deriving this nonlinear model are also outlined. A successful feasibility study of the proposed controller is presented for an experimental greenhouse located at the University of South Toulon-Var (France). Simulation results show promising performances despite the high interaction between the process internal variables and the high impact on these variables of the external meteorological conditions.

Numerical simulation of air flow field in single-sided ventilated buildings

The present paper refers to the numerical prediction of air velocities and temperatures inside single-sided naturally ventilated buildings and more specifically the special case in which air from the external environment is brought into the building through single-directed openings. The work is focused on the physical procedures governing air movement during the single-sided natural ventilation. The study presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature, prevailing in three-dimensional, single-sided ventilated buildings with openings of any geometrical complexity, for given external meteorological conditions. The mathematical model involves the partial differential equations governing flow and heat transfer in large enclosures. Turbulent flow is simulated and buoyancy effects are taken into account. The model is used to assess the environmental conditions in a test cell designed and constructed by the National Observatory of Athens with external conditions corresponding to their measurements. The numerical results are in good agreement with the experimental values of air velocity, temperature and pressure, at various sites inside the test cell.

Computational analysis of thermal comfort: the case of the archaeological museum of Athens

The paper presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature prevailing in three-dimensional buildings of any geometrical complexity, for given external meteorological conditions. The model involves the partial differential equations governing flow and heat transfer, in large enclosures, containing heat sources. Turbulent flow is simulated and buoyancy effects are taken into account. The model allows for such practical aspects of the problems under consideration as blockages, internal heat loads, external weather conditions, the presence of people, etc. The model is used to assess the environmental conditions inside the main Hall of the National Archaeological Museum of Athens (Myceane Hall) with external conditions corresponding to Ministry of Environment, summer and winter days.